Electrical and Electronics Engineering publications abstract of: 01-2018 sorted by title, page: 13

» Non-Model-Based Control of a Wheeled Vehicle Pulling Two Trailers to Provide Early Powered Mobility and Driving Experiences
Abstract:
Non-model-based control of a wheeled vehicle pulling two trailers is proposed. It is a fun train for disabled children consisting of a locomotive and two carriages. The fun train has afforded opportunities for both disabled and able bodied young people to share an activity and has provided early driving experiences for disabled children; it has introduced them to assistive and powered mobility. The train is a nonlinear system and subject to nonholonomic kinematic constraints, so that position and state depend on the path taken to get there. The train is described, and then, a robust control algorithm using proportional–derivative filtered errors is proposed to control the locomotive. The controller was not dependent on an accurate model of the train, because the mass of the vehicle and two carriages changed depending on the number, size, and shape of children and wheelchair seats on the train. The controller was robust and stable in uncertainty. Results are presented to show the effectiveness of the approach, and the suggested control algorithm is shown to be acceptable without knowing the exact plant dynamics.
Autors: David A. Sanders TD VR;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Jan 2018, volume: 26, issue:1, pages: 96 - 104
Publisher: IEEE
 
» Non-Overlapping Subsequence Matching of Stream Synopses
Abstract:
In this paper, we propose SUbsequence Matching framework with cell MERgence (SUMMER) for online subsequence matching between histogram-based stream synopsis structures under the dynamic time warping distance. Given a query synopsis pattern, SUMMER continuously identifies all the matching subsequences for a stream as the bins are generated. To effectively reduce the computation time, we design a Weighted Dynamic Time Warping (WDTW) algorithm, which computes the warping distance directly between two histogram-based synopses. Furthermore, a Stack-based Overlapping Filter Algorithm (SOFA) is provided to remove the overlapping subsequences to avoid the redundant information. Finally, we design an optional refinement module to relax the subsequence range limit and improve the matching accuracy. Our experiments on real datasets show that the proposed method significantly speeds up the pattern matching without compromising the accuracy required when compared with other approaches.
Autors: Su-Chen Lin;Mi-Yen Yeh;Ming-Syan Chen;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jan 2018, volume: 30, issue:1, pages: 101 - 114
Publisher: IEEE
 
» Non-Rigid Contour-Based Registration of Cell Nuclei in 2-D Live Cell Microscopy Images Using a Dynamic Elasticity Model
Abstract:
The analysis of the pure motion of subnuclear structures without influence of the cell nucleus motion and deformation is essential in live cell imaging. In this paper, we propose a 2-D contour-based image registration approach for compensation of nucleus motion and deformation in fluorescence microscopy time-lapse sequences. The proposed approach extends our previous approach, which uses a static elasticity model to register cell images. Compared with that scheme, the new approach employs a dynamic elasticity model for the forward simulation of nucleus motion and deformation based on the motion of its contours. The contour matching process is embedded as a constraint into the system of equations describing the elastic behavior of the nucleus. This results in better performance in terms of the registration accuracy. Our approach was successfully applied to real live cell microscopy image sequences of different types of cells including image data that was specifically designed and acquired for evaluation of cell image registration methods. An experimental comparison with the existing contour-based registration methods and an intensity-based registration method has been performed. We also studied the dependence of the results on the choice of method parameters.
Autors: Dmitry V. Sorokin;Igor Peterlik;Marco Tektonidis;Karl Rohr;Pavel Matula;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2018, volume: 37, issue:1, pages: 173 - 184
Publisher: IEEE
 
» Noncoherent OFDM-IM and Its Performance Analysis
Abstract:
In conventional orthogonal frequency division multiplexing (OFDM) with index modulation (OFDM-IM), the active subcarriers can convey information bits by modulated symbols as well as their indices. To detect modulated symbols, coherent detection is usually considered, which requires the channel state information (CSI) estimation for all subcarriers at a receiver. In OFDM-IM, however, since only a fraction of subcarriers are active, the overhead for pilot transmissions through all subcarriers to allow the receiver to estimate the CSI could be excessive, in particular, under a fast fading environment. To avoid this difficulty, we consider noncoherent OFDM-IM, where only the indices of active subcarriers are used to convey information bits. For a better performance, a transmit diversity scheme is also studied. We derive a closed-form expression for the probability of index error when no transmit diversity is considered under frequency-selective Rayleigh fading. We also derive an upper-bound when the transmit diversity scheme is employed. From the upper-bound, the diversity order is also clearly shown.
Autors: Jinho Choi;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 352 - 360
Publisher: IEEE
 
» Noncooperative Game-Based Distributed Charging Control for Plug-In Electric Vehicles in Distribution Networks
Abstract:
Increasing penetration of plug-in electric vehicles (PEVs) has a substantial impact on the operation of power distribution networks. Given the fast-growing load demands from PEVs and unmatched infrastructure investment in transformer and feeder capacity, the PEV charging is subjected to both spatially and temporally security constraints beyond which the network failure may occur. This paper proposes a game-theory-based distributed charging control method to coordinate large-scale PEVs without compromising the security of the distribution network. Under a noncooperative game framework, a price-driven charging model is designed to minimize the cost of each individual PEV customer while satisfying the network loading constraints. Then, a Newton-type method is developed to find a better Nash equilibrium of the game model at a superlinear convergence rate. Furthermore, an accelerated gradient method is proposed to tackle the subproblem for each user's best response. The update of the user's best response is implemented in a distributed way in order to protect user's privacy. The convergence rate of the proposed algorithms is rigorously proved. The effectiveness and efficiency of the proposed methods are tested on the IEEE 13-bus system.
Autors: Jueyou Li;Chaojie Li;Yan Xu;Zhao Yang Dong;Kit Po Wong;Tingwen Huang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Jan 2018, volume: 14, issue:1, pages: 301 - 310
Publisher: IEEE
 
» Nonlane-Discipline-Based Car-Following Model for Electric Vehicles in Transportation- Cyber-Physical Systems
Abstract:
This paper proposes a new car-following (CF) model incorporating the effects of lateral gap and roadside device communication to capture the characteristics of electric vehicle (EV) traffic stream in transportation-cyber-physical systems. Stability of the proposed CF model is analyzed using the perturbation method. Furthermore, the energy consumption of the EV traffic stream is investigated based on the drive cycles produced by the proposed model. Numerical experiments analyze three scenarios: start, stop, and evolution processes for the scenarios of no lateral gap, lateral gap, and lateral gap with roadside device, respectively. Results demonstrate that: 1) the nonlane-discipline-based model is more responsive than the lane-discipline-based model; 2) the nonlane-discipline-based model for the EV traffic stream consumes more energy in the acceleration phase and recuperates more energy in the deceleration phase compared with the lane-discipline-based model; and 3) the nonlane-discipline-based model with roadside device communication for EV traffic stream consumes more energy in the acceleration phase and recuperates more energy in the deceleration phase than the model without roadside devices.
Autors: Yongfu Li;Li Zhang;Hong Zheng;Xiaozheng He;Srinivas Peeta;Taixiong Zheng;Yinguo Li;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2018, volume: 19, issue:1, pages: 38 - 47
Publisher: IEEE
 
» Nonlinear Dot Plots
Abstract:
Conventional dot plots use a constant dot size and are typically applied to show the frequency distribution of small data sets. Unfortunately, they are not designed for a high dynamic range of frequencies. We address this problem by introducing nonlinear dot plots. Adopting the idea of nonlinear scaling from logarithmic bar charts, our plots allow for dots of varying size so that columns with a large number of samples are reduced in height. For the construction of these diagrams, we introduce an efficient two-way sweep algorithm that leads to a dense and symmetrical layout. We compensate aliasing artifacts at high dot densities by a specifically designed low-pass filtering method. Examples of nonlinear dot plots are compared to conventional dot plots as well as linear and logarithmic histograms. Finally, we include feedback from an expert review.
Autors: Nils Rodrigues;Daniel Weiskopf;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 616 - 625
Publisher: IEEE
 
» Nonlinear Equivalent Magnetic Network of a Linear Permanent Magnet Vernier Machine With End Effect Consideration
Abstract:
A nonlinear equivalent magnetic network (EMN) model is proposed for a linear permanent magnet vernier (LPMV) machine. The meshing method is employed to solve the problem of the modeling of complex flux paths in stator teeth tips. Especially, an end-region model based on the electromagnetic principle is developed to consider the longitudinal end effect of the LPMV machine. The key contribution of this paper is to present a faster and simpler approach to separate the detent force (end force component and cogging force component) than finite-element analysis (FEA). Besides, taking the iron saturation and air-gap flux leakage into account, the proposed model is used to predict the electromagnetic performances of the LPMV machine, such as air-gap flux density, back-electromotive force, cogging force, and thrust force. Finally, through comparisons among the FEA simulations, experimental measurements and EMN analyses, the accuracy and effectiveness of the proposed model are verified.
Autors: Guohai Liu;Ling Ding;Wenxiang Zhao;Qian Chen;Shan Jiang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2018, volume: 54, issue:1, pages: 1 - 9
Publisher: IEEE
 
» Nonlocal Filtering Applied to 3-D Reconstruction of Tomographic SAR Data
Abstract:
In this paper, we introduce two spatially adaptive filtering methods to improve the estimation of the covariance matrix (CM), which is required for the processing of tomographic SAR data. We evaluate their effect on scatterer separation and height estimation. We propose several criteria to evaluate such methods and introduce a spatial simulation procedure allowing generating a tomographic image stack from a 3-D building model, assuming a multitrack airborne configuration and a distributed target model incorporating multidimensional speckle. Inversion of such a model requires the estimation of a CM from the data. Consequently, we propose two nonlocal methods to improve the estimation of the CM. The first one was previously introduced for polarimetric data and uses pixel similarities based on Riemannian distances between CMs. The second one is a new method extending the previous one to similarities between patches. We show the importance of spatial adaptivity in covariance estimation by comparing the 3-D reconstructions obtained with our filters and other methods. Further experiments on simulated and L-band experimental data show the ability of the nonlocal filters to improve the height estimation and scatterer separation in layover areas thanks to their smoothing and edge-preserving properties.
Autors: Olivier D’Hondt;Carlos López-Martínez;Stéphane Guillaso;Olaf Hellwich;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jan 2018, volume: 56, issue:1, pages: 272 - 285
Publisher: IEEE
 
» Nonparametric Prediction Intervals of Wind Power via Linear Programming
Abstract:
This letter proposes a machine learning-based linear programming model that quickly establishes the nonparametric prediction intervals of wind power by integrating extreme learning machine and quantile regression. The proportions of quantiles can be adaptively determined via sensitivity analysis. The proposed method has been proven to be significantly efficient and reliable, with a high application potential in power systems.
Autors: Can Wan;Jianhui Wang;Jin Lin;Yonghua Song;Zhao Yang Dong;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 1074 - 1076
Publisher: IEEE
 
» Nonuniform Line Generator for High-Power RF Applications
Abstract:
Line generators were attractive structures for high-power radio frequency (RF) pulse generation for two decades. Due to some disadvantages, there has been little attention to this type of generator for a relatively long time. In this paper, a nonuniform line generator is used which resolves some of the main shortcomings of conventional line generators. The considered generator can generate RF pulses at higher frequencies with considerably higher repetition rates. Furthermore, the implementation of nonuniform line generators is significantly easier than that of their conventional counterparts. Measurement results for three nonuniform line generators are presented. The possibility of generating ~10 s MW RF powers with ~100 s MHz central frequencies at ~1-kHz repetition rates is discussed. It is shown that the used technique in this paper can be a serious rival to lumped element nonlinear transmission lines (NLTLs).
Autors: Mohammad Samizadeh Nikoo;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2018, volume: 46, issue:1, pages: 64 - 71
Publisher: IEEE
 
» Normalized Scalar Product Approach for Nearshore Bathymetric Estimation From X-Band Radar Images: An Assessment Based on Simulated and Measured Data
Abstract:
This paper investigates the capability of X-band radar systems to estimate nearshore bathymetry fields by considering both simulated and measured radar data. For the first time, a sensitivity analysis is performed to evaluate how sea-state conditions affect bathymetric estimates. For this purpose, sea wave fields generated by means of a numerical model, based on a nonlinear shallow-water equation solver, are used. Starting from the synthetic radar data, which represent the input of the bathymetric estimation algorithm, the bathymetric reconstruction is performed through the normalized scalar product (NSP) estimation strategy, exploiting a spatial partitioning of the radar data. In this way, it is possible to improve the accuracy of the estimates in nearshore areas, where the space-varying behavior of the sea depth and the presence of coastlines or coastal structures typically leads to a spatial inhomogeneity of the wave motion. In this regard, it is shown how the choice of the partitioning settings affects the bathymetric estimates obtained from high-resolution X-band radar images by using the NSP strategy. In addition, an adaptive partitioning strategy that takes into account the wave evolution in nearshore shallow waters is devised. Based on both simulated and measured radar data, the accuracy of the bathymetric estimates achievable through the proposed adaptive partitioning process and that obtained by exploiting the approach using uniform spatial partitioning are compared. The results obtained confirm the robustness of the NSP technique with respect to sea conditions and, moreover, demonstrate that the proposed adaptive partitioning strategy provides more accurate bathymetric estimates than those obtained with the space-invariant partitioning procedure.
Autors: Giovanni Ludeno;Matteo Postacchini;Antonio Natale;Maurizio Brocchini;Claudio Lugni;Francesco Soldovieri;Francesco Serafino;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2018, volume: 43, issue:1, pages: 221 - 237
Publisher: IEEE
 
» Novel Adaptive Multi-Clustering Algorithm-Based Optimal ESS Sizing in Ship Power System Considering Uncertainty
Abstract:
The optimal sizing of an energy storage system (ESS) in a power generation system that incorporates photovoltaic (PV) generation is crucial in a power grid for which the reduction of CO2 emissions is important. This problem is particularly challenging when it relates to the power system of a ship because it involves uncertain meteorological and load data along a navigation route. This paper proposes a novel method for multi-objective minimization of investment/replacement cost, fuel cost, and CO2 emissions, to find the optimal size of the ESS considering life-span of the ESS. The generation of power by PV modules on a ship is affected by temporal and geographical variations of irradiation along the navigation route. In particular, operating load conditions and irradiation are uncertain. This paper proposes a novel algorithm for partitioning high-dimensional uncertain data into tractable clusters solved by deterministic optimization method. Case studies of an all-electric ship along a route from Dalian in China to Aden in Yemen are shown to demonstrate the applicability of the proposed clustering-based stochastic optimization method.
Autors: Chi Yao;Minyou Chen;Ying-Yi Hong;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 307 - 316
Publisher: IEEE
 
» Novel Design for a Rectenna to Collect Pulse Waves at 2.4 GHz
Abstract:
A novel rectifying circuit topology is proposed for converting electromagnetic pulse waves (PWs), that are collected by a wideband antenna, into dc voltage. The typical incident signal considered in this paper consists of 10-ns pulses modulated around 2.4 GHz with a repetition period of 100 ns. The proposed rectifying circuit topology comprises a double-current architecture with inductances that collect the energy during the pulse delivery as well as an output capacitance that maintains the dc output voltage between the pulses. Experimental results show that the efficiency of the rectifier reaches 64% for a mean available incident power of 4 dBm. Similar performances are achieved when a wideband antenna is combined with the rectifier in order to realize a rectenna. By increasing the repetition period of the incident PWs to 400 ns, the rectifier still operates with an efficiency of 52% for a mean available incident pulse power of −8 dBm. Finally, the proposed PW rectenna is tested for a wireless energy transmission application in a low- cavity. The time reversal technique is applied to focus PWs around the desired rectenna. Results show that the rectenna is still efficient when noisy PW is handled.
Autors: Rony Ibrahim;Damien Voyer;Mohamad El Zoghbi;Julien Huillery;Arnaud Bréard;Christian Vollaire;Bruno Allard;Youssef Zaatar;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2018, volume: 66, issue:1, pages: 357 - 365
Publisher: IEEE
 
» Novel EKF-Based Vision/Inertial System Integration for Improved Navigation
Abstract:
With advances in computing power, stereo vision has become an essential part of navigation applications. However, there may be instances wherein insufficient image data precludes the estimation of navigation parameters. Earlier, a novel vision-based velocity estimation method was developed by the authors, which suffered from the aforementioned drawback. In this paper, the vision-based navigation method has been integrated with a unique low-cost reduced inertial sensor system to bridge the navigation gap using one gyroscope and two accelerometers along with the inputs from wheel speed sensors. The integrated system is based on the extended Kalman filter and was tested on three trajectories with the introduction of vision data gaps. The system showed promising results for autonomous land vehicle applications.
Autors: Tashfeen B. Karamat;Romulo Gonçalves Lins;Sidney N. Givigi;Aboelmagd Noureldin;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2018, volume: 67, issue:1, pages: 116 - 125
Publisher: IEEE
 
» Novel Inductive Wireless Power Transfer Uplink Utilizing Rectifier Third-Order Nonlinearity
Abstract:
This paper proposes a new approach for inductive wireless power transfer (IWPT) tag-to-reader communication. A new technique to achieve transmitter/receiver (Tx/Rx) frequency separation is demonstrated. A two-tone Tx is adopted at the reader, and the third-order intermodulation (IM3) frequency generated by the tag rectifier nonlinearity is used as the Rx carrier, which is modulated by a baseband signal sent by the tag. The uplink signal at the IM3 frequency can be picked up by the reader coil. The IWPT impedance matching networks for both the reader and the tag coil can be reused efficiently, since the IM3 frequency at 5.06 GHz is close to the Tx fundamental frequencies at 4.94 and 5 GHz. Due to the Tx/Rx frequency separation, the Tx-to-Rx leakage at the Rx frequency can be suppressed by external filters to improve the Rx signal-to-noise ratio (SNR). The proposed technique is implemented within a 5-GHz IWPT system, and a tiny CMOS tag with a coil size of only 0.01 mm2 is used. This paper also implements conventional direct and intermediate frequency-based backscattering uplinks for comparison, and the proposed IM3 uplink is able to improve the Rx SNR by more than 20 dB. The achieved uplink data rate (100 kb/s) is also higher than the published work (20 kb/s) that adopted the conventional backscattering method.
Autors: Nai-Chung Kuo;Bo Zhao;Ali M. Niknejad;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2018, volume: 66, issue:1, pages: 319 - 331
Publisher: IEEE
 
» Novel Multi-Step Short-Term Wind Power Prediction Framework Based on Chaotic Time Series Analysis and Singular Spectrum Analysis
Abstract:
Decomposition methods are widely applied as a prestage of wind power prediction (WPP) to reduce the prediction errors caused by the nonstationarity and nonlinearity of wind power time series (TS); however, they cannot address the issues posed by the chaotic behavior of wind power TS. This paper, therefore, proposes a novel decomposition approach to take the chaotic nature of wind power TS into account and to improve WPP accuracy. In this decomposition approach, as a primary step, the wind power TS is separated into several components with different time-frequency characteristics (scales) by means of ensemble empirical mode decomposition. Chaotic TS analysis is then applied to determine which components are chaotic, and then singular spectrum analysis (SSA) is applied thereto. This multi-scale SSA (MSSSA) can maintain the general trend of chaotic components, which become smoother by eliminating extremely rapid changes with low amplitudes, and thus several steps ahead WPP with higher accuracy can be realized. Following the proposed decomposition, a novel short-term WPP method comprised of localized direct and iterative prediction is proposed to perform multi-step prediction for the chaotic and nonchaotic components of MSSSA, respectively. The proposed framework is finally validated using historical data related to overall wind power generation for Alberta (Canada), the Sotavento wind farm (Spain), and Centennial wind farm in Saskatchewan (Canada).
Autors: Nima Safari;C. Y. Chung;G. C. D. Price;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 590 - 601
Publisher: IEEE
 
» Numerical Investigation on the Electrical Characteristics and Electron Energy Transformation of Pulsed Dielectric Barrier Discharge for Ozone Generation
Abstract:
A numerical model consisting of 12 species and 65 reactions is developed and experimentally verified to be valid for the investigation of electrical characteristics and electron energy transformation in oxygen-fed pulsed dielectric barrier discharge (DBD) for ozone generation. The simulation results show that there are two obvious discharges with opposite polarity in one pulse which agrees with many experimental observations. The first discharge is at the rising edge of pulse voltage, and the second discharge is at the falling edge. The former has a much higher current density than that of the latter. Moreover, a higher peak voltage results in an earlier and higher ignition voltage as well as a higher maximum current density. The contrary behavior for rising time is observed, and the ignition and maximum current density are independent of pulsewidth. In addition, the temporal distributions of total input power density, electron power density, and power density of electron consumed by reactions are obtained for the first discharge in DBD for the ozone generation. Only 19.35% of the total input energy within the first discharge is absorbed by electrons when peak voltage, rising time, and pulsewidth are 9 kV, 63.8 ns, and 100 ns, respectively, and 41.09% of electron energy is utilized effectively to form ozone.
Autors: Yafang Zhang;Xin Liang;Jinfeng Li;Linsheng Wei;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2018, volume: 46, issue:1, pages: 103 - 109
Publisher: IEEE
 
» Numerical Study on Mode Transition Characteristics in Atmospheric-Pressure Helium Pulsed Discharges With Pin–Plane Electrode
Abstract:
A 2-D fluid model is developed to study the pulsed discharges with pin–plane electrode in atmospheric pressure. A positive streamer forms at the pin electrode connecting to the applied voltage and then propagates toward to the ground plane electrode (cathode). Simulation results show if the streamer head is close enough to the cathode, in front of the original streamer a new streamer forms, and simultaneously a second positive current peak is observed, suggesting that the discharge mode transforms into glow mode. Otherwise, the discharge operates at corona mode. The characteristics of the two typical discharge modes are analyzed through the spatiotemporal evolution behaviors of conduction current, electron density, electric field, and electron flux. The transition between corona and glow modes depending on the discharge parameters such as applied voltage, curvature radii, and secondary electron emission coefficients are studied in this paper. It should be noted that no matter what discharge mode is, discharge with reversed direction appears at the falling edge of voltage pulse, which is caused by space charges.
Autors: Jiao Zhang;Yanhui Wang;Dezhen Wang;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2018, volume: 46, issue:1, pages: 19 - 24
Publisher: IEEE
 
» Object Proposal Generation With Fully Convolutional Networks
Abstract:
Object proposal generation, as a preprocessing technique, has been widely used in current object detection pipelines to guide the search of objects and avoid exhaustive sliding window search across images. Current object proposals are mostly based on low-level image cues, such as edges and saliency. However, objectness is possibly a high-level semantic concept showing whether one region contains objects. This paper presents a framework utilizing fully convolutional networks (FCNs) to produce object proposal positions and bounding box location refinement with Support Vector Machine (SVM) to further improve proposal localization. Experiments on the PASCAL VOC 2007 show that using high-level semantic object proposals obtained by FCN, the object recall can be improved. An improvement in detection mean average precision is also seen when using our proposals in the Fast R-convolutional neural network framework. In addition, we also demonstrate that our method shows stronger robustness when introduced to image perturbations, e.g., blurring, JPEG compression, and salt and pepper noise. Finally, the generalization capability of our model (trained on the PASCAL VOC 2007) is evaluated and validated by testing on PASCAL VOC 2012 validation set, ILSVRC 2013 validation set, and MS COCO 2014 validation set.
Autors: Zequn Jie;Wen Feng Lu;Siavash Sakhavi;Yunchao Wei;Eng Hock Francis Tay;Shuicheng Yan;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jan 2018, volume: 28, issue:1, pages: 62 - 75
Publisher: IEEE
 
» Object-Based Change Detection for VHR Images Based on Multiscale Uncertainty Analysis
Abstract:
Scale is of great significance in image analysis and interpretation. In order to utilize scale information, multiscale fusion is usually employed to combine change detection (CD) results from different scales. However, CD results from different scales are usually treated independently, which ignores the scale contextual information. To overcome this drawback, this letter introduces a novel object-based change detection (OBCD) technique for unsupervised CD in very high-resolution (VHR) images by incorporating multiscale uncertainty analysis. First, two temporal images are stacked and segmented using a series of optimal segmentation scales ranging from coarse to fine. Second, an initial CD result is obtained by fusing the pixel-based CD result and OBCD result based on Dempter–Shafer (DS) evidence theory. Third, multiscale uncertainty analysis is implemented from coarse scale to fine scale by support vector machine classification. Finally, a CD map is generated by combining all the available information in all the scales. The experimental results employing SPOT5 and GF-1 images demonstrate the effectiveness and superiority of the proposed approach.
Autors: Yongjun Zhang;Daifeng Peng;Xu Huang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2018, volume: 15, issue:1, pages: 13 - 17
Publisher: IEEE
 
» Object-Based Superresolution Land-Cover Mapping From Remotely Sensed Imagery
Abstract:
Superresolution mapping (SRM) is a widely used technique to address the mixed pixel problem in pixel-based classification. Advanced object-based classification will face a similar mixed phenomenon—a mixed object that contains different land-cover classes. Currently, most SRM approaches focus on estimating the spatial location of classes within mixed pixels in pixel-based classification. Little if any consideration has been given to predicting where classes spatially distribute within mixed objects. This paper, therefore, proposes a new object-based SRM strategy (OSRM) to deal with mixed objects in object-based classification. First, it uses the deconvolution technique to estimate the semivariograms at target subpixel scale from the class proportions of irregular objects. Then, an area-to-point kriging method is applied to predict the soft class values of subpixels within each object according to the estimated semivariograms and the class proportions of objects. Finally, a linear optimization model at object level is built to determine the optimal class labels of subpixels within each object. Two synthetic images and a real remote sensing image were used to evaluate the performance of OSRM. The experimental results demonstrated that OSRM generated more land-cover details within mixed objects than did the traditional object-based hard classification and performed better than an existing pixel-based SRM method. Hence, OSRM provides a valuable solution to mixed objects in object-based classification.
Autors: Yuehong Chen;Yong Ge;Gerard B. M. Heuvelink;Ru An;Yu Chen;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jan 2018, volume: 56, issue:1, pages: 328 - 340
Publisher: IEEE
 
» Observation of Whispering-Gallery Modes in a Diamond Microsphere
Abstract:
We demonstrate a Type Ib diamond (nitrogen impurity of >5 ppm) microsphere whispering-gallery mode resonator in the near-infrared wavelengths between 1426.10 nm and 1427.42 nm in the 90° elastic-light-scattering for both transverse magnetic (TM) and transverse electric (TE) polarizations. The highest measured whispering-gallery mode quality-factor is in the order of 104, and the mode spacing is 0.332 nm both for TM and TE polarizations. The coupling of the continuous-wave tunable infrared excitation laser to the diamond microsphere is achieved by a single-mode silica optical-fiber half-coupler. Such a diamond resonator can further be used as stable optical-frequency-comb generating or lasing microcavities by exploiting the nitrogen-vacancy centers present within the diamond.
Autors: Mustafa Mert Bayer;Hüseyin Ozan Çirkinoğlu;Ali Serpengüzel;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:1, pages: 3 - 6
Publisher: IEEE
 
» Off-Body Spatial Diversity Reception Using Circular and Linear Polarization: Measurement and Modeling
Abstract:
A novel circular polarized (CP) spatial diversity reception scheme is proposed to mitigate the human-body-related fading in off-body communication. Compared with the typical linear polarized (LP) diversity receptions, it seems that the proposed scheme can effectively reduce the root mean square delay spread, multi-path component numbers, and their variations over different persons and measured locations. Both the signal-level models of LP and CP diversity receptions which take the polarization misalignment into consideration are mathematically derived with the help of diversity gain and cross polarized discrimination gain factor. The equal-gain-combination signal levels for CP diversity reception are verified to be around 2.1 dB greater than the LP reception, if the polarization mismatch loss is removed. Furthermore, the great signal-level fluctuation caused by the polarization misalignment effect can be mitigated by introducing CP reception when comparing with LP one. The proposed scheme is expected to be useful for designing robust off-body communications.
Autors: Peng-Fei Cui;Wen-Jun Lu;Yu Yu;Bai Xue;Hong-Bo Zhu;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 209 - 212
Publisher: IEEE
 
» Ohmic Contact-Free Mobility Measurement in Ultra-Wide Bandgap AlGaN/AlGaN Devices
Abstract:
We measure the electron density dependence of carrier mobility in ultra-wide bandgap Al0.85Ga0.15N/Al0.7Ga0.3N heterostructures, using only Au/Pt Schottky contact deposition and without the need for Ohmic contacts. With this technique, we measure mobility over a two-dimensional electron gas density range from 1010 to 1013 cm−2 at an AlGaN/AlGaN heterojunction. At room temperature, subthreshold mobility was 4 cm2/Vs and peak mobility 155 cm2/Vs. Peak mobility decreased with temperature as T−0.86 suggesting alloy scattering as the dominant scattering mechanism.
Autors: Peter A. Butler;William M. Waller;Michael J. Uren;Andrew Allerman;Andrew Armstrong;Robert Kaplar;Martin Kuball;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2018, volume: 39, issue:1, pages: 55 - 58
Publisher: IEEE
 
» Oleic Acid Surface Modification in the Preparation of Magnetic Nanoparticles by a Chemically Induced Transition
Abstract:
Using a chemically induced transition method, magnetic nanoparticles of -Fe2O3 coated by FeCl3 6H2O (-Fe2O3/FeCl3 6H2O nanoparticles) can be prepared. Surface modification is performed using oleic acid. By adding oleic acid during the synthesis, FeCl3 6H2O can be replaced to produce nanoparticles of -Fe2O3 coated by a monolayer of oleic acid (-Fe2O3/oleic acid nanoparticles). The amount of oleic acid added is sufficient, with the as-prepared sample single -Fe2O3/oleic acid nanoparticles, whereas the as-prepared sample is a mixture of both -Fe2O3/FeCl3 6H2O and -Fe2O3/oleic acid nanoparticles. By chemical species analysis, the mass fraction of both the -Fe2O3 phase and oleic acid adsorbed can be estimated. These magnetic nanoparticles coated by olei- acid can be considered as effective nanoparticles with an effective density . The reflects the amount of oleic acid chemisorbed on the nanoparticles. A kerosene-based suspension comprising the effective nanoparticles was synthesized. Results for the specific saturation magnetization and density of the suspension confirm the effective particle structure, involving the mass fraction of oleic acid adsorbed and the effective density of the effective particles.
Autors: Xiangshen Meng;Zhenghong He;Jianwei Zhao;Yueqiang Lin;Xiaodong Liu;Decai Li;Jian Li;Xiaoyan Qiu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2018, volume: 54, issue:1, pages: 1 - 7
Publisher: IEEE
 
» On Choosing Training and Testing Data for Supervised Algorithms in Ground-Penetrating Radar Data for Buried Threat Detection
Abstract:
Ground-penetrating radar (GPR) is one of the most popular and successful sensing modalities that have been investigated for landmine and subsurface threat detection. Many of the detection algorithms applied to this task are supervised and therefore require labeled examples of threat and nonthreat data for training. Training data most often consist of 2-D images (or patches) of GPR data, from which features are extracted and provided to the classifier during training and testing. Identifying desirable training and testing locations to extract patches, which we term “keypoints,” is well established in the literature. In contrast, however, a large variety of strategies have been proposed regarding keypoint utilization (e.g., how many of the identified keypoints should be used at threat, or nonthreat, locations). Given a variety of keypoint utilization strategies that are available, it is very unclear: 1) which strategies are best or 2) whether the choice of strategy has a large impact on classifier performance. We address these questions by presenting a taxonomy of existing utilization strategies and then evaluating their effectiveness on a large data set using many different classifiers and features. We analyze the results and propose a new strategy, called PatchSelect, which outperforms other strategies across all experiments.
Autors: Daniël Reichman;Leslie M. Collins;Jordan M. Malof;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jan 2018, volume: 56, issue:1, pages: 497 - 507
Publisher: IEEE
 
» On Codes Achieving Zero Error Capacities in Limited Magnitude Error Channels
Abstract:
Shannon in his 1956 seminal paper introduced the concept of the zero error capacity, , of a noisy channel. This is defined as the least upper bound of rates, at which, it is possible to transmit information with zero probability of error. At present not many codes are known to achieve the zero error capacity. In this paper, some codes which achieve zero error capacities in limited magnitude error channels are described. The code lengths of these zero error capacity achieving codes can be of any finite length , in contrast to the long lengths required for the known regular capacity achieving codes, such as turbo codes, LDPC codes, and polar codes. Both wrap around and non-wrap around limited magnitude error models are considered in this paper. For non-wrap around error model, the exact value of zero error capacities is derived, and optimal non-systematic and systematic codes are designed. The non-systematic codes achieve the zero error capacity with any finite length. The optimal systematic codes achieve the systematic zero error capacity of the channel, which is defined as the zero error capacity with the additional requirements that the communication must be carried out with a systematic code. It is also shown that the rates of the proposed systematic codes are equal to or approximately equal to the zero error capacity of the channel. For the wrap around model bounds are derived for the zero error capacity and in many cases the bounds give the exact value. In addition, optimal wrap around non-systematic and systematic codes are developed which either achieve or are close to achieving the zero error capacity with finite length.
Autors: Bella Bose;Noha Elarief;Luca G. Tallini;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2018, volume: 64, issue:1, pages: 257 - 273
Publisher: IEEE
 
» On Communication Through a Gaussian Channel With an MMSE Disturbance Constraint
Abstract:
This paper considers a Gaussian channel with one transmitter and two receivers. The goal is to maximize the communication rate at the intended/primary receiver subject to a disturbance constraint at the unintended/secondary receiver. The disturbance is measured in terms of the minimum mean square error (MMSE) of the interference that the transmission to the primary receiver inflicts on the secondary receiver. This paper presents a new upper bound for the problem of maximizing the mutual information subject to an MMSE constraint. The new bound holds for vector inputs of any length and recovers a previously known limiting (when the length of the vector input tends to infinity) expression from the work of Bustin et al. The key technical novelty is a new upper bound on the MMSE. This bound allows one to bound the MMSE for all signal-to-noise ratio (SNR) values below a certain SNR at which the MMSE is known (which corresponds to the disturbance constraint). The bound also complements the “single-crossing point property” of the MMSE that upper bounds the MMSE for all SNR values above a certain value at which the MMSE value is known. The MMSE upper bound provides a refined characterization of the phase-transition phenomenon, which manifests, in the limit as the length of the vector input goes to infinity, as a discontinuity of the MMSE for the problem at hand. For vector inputs of size , a matching lower bound, to within an additive gap of order (where is the disturbance constraint), is shown by means of the mixed inputs technique recently introduced by Dytso et al.
Autors: Alex Dytso;Ronit Bustin;Daniela Tuninetti;Natasha Devroye;H. Vincent Poor;Shlomo Shamai Shitz;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2018, volume: 64, issue:1, pages: 513 - 530
Publisher: IEEE
 
» On Expected Neighbor Discovery Time With Prior Information: Modeling, Bounds and Optimization
Abstract:
Neighbor discovery (ND) is an essential prerequisite for any peer-to-peer communication. In general, minimizing the discovery time is the goal for ND schemes. In this paper, we study the average discovery time for directional random ND when nodes have prior information about their set of possible neighbors, which also helps identify the performance limits of random ND schemes. Typically, discovery time analysis is done for assumptions that simplify the network structure, such as uniform neighbor relations for all nodes. However, with prior information the directional transmission probabilities depend on the node and the direction. This complicates the analysis of the expected discovery time. We first provide a closed-form expression for the expected discovery time based on the non-uniform coupon collector problem. Next, we identify directional transmission probabilities of each node that achieve a small discovery time. Due to the mathematical complexity, we provide a lower and an upper bound on the expected discovery time, which allows us to write the problem as a convex optimization problem. Through simulations, we demonstrate the performance gain due to prior knowledge with the proposed methods as compared with when no prior information is available, as well as the impact of uncertainty in the prior knowledge.
Autors: Daoud Burghal;Arash Saber Tehrani;Andreas F. Molisch;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 339 - 351
Publisher: IEEE
 
» On Inertia Distribution, Inter-Area Oscillations and Location of Electronically-Interfaced Resources
Abstract:
This paper explores the relationships between inertia distribution, inter-area oscillations, and location of electronically-interfaced resources that are enabled with either damping or inertia emulation controllers (EIRs). A two-machine system with an EIR is used for analytical derivations. Explicit analytical expressions are found for: (a) the location of the center of inertia (COI), which depends on the H-inertia constant and voltage set-points of the machines, and (b) the residue of the system transfer function, which is convex in terms of the EIR location. These expressions are validated using full-order models for machines, exciters, and governors; the results support the idea of placing EIRs further away from the COI, or equivalently, in areas with low inertia to attain the highest possible oscillation damping. In the case of large-scale systems, an inertia distribution index is proposed which allows estimating the distance from any bus to the COI location. The efficacy of the proposed index is tested in a real system. The system areas with less inertia are proved to be the best places to deploy EIRs. The proposed index does not require computationally expensive calculations as those from modal analysis and it seems promising to better reinforce power system dynamics through EIRs.
Autors: Héctor Pulgar-Painemal;Yajun Wang;Horacio Silva-Saravia;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 995 - 1003
Publisher: IEEE
 
» On Random Dynamic Voltage Scaling for Internet-of-Things: A Game-Theoretic Approach
Abstract:
Security is one of the top considerations in hardware designs for Internet-of-Things (IoT), where embedded cryptosystems are extensively used. Traditionally, random dynamic voltage scaling technology has been shown to be very effective in improving the resistance of cryptosystems against side-channel attacks. However, in this paper we demonstrate that the resistance can be undermined by providing lower off-chip power supply voltage. In order to address this issue, we then further propose to monitor the off-chip power supply voltage, and trigger an alarm to protect valued information once the power supply voltage is lower than the expected voltage (threshold voltage). However, considering both maintenance cost of IoT devices and the environment noise on power supply voltage, we first formulated this problem as a nonzero sum game model, and the attacker and the circuit supplier (defender) are the players of this game. The analysis of the Nash equilibria in this game show interesting guideline to the defender about the choice of threshold voltage, which is based on parameters of cryptosystem including the value of information, denial-of-service cost in IoT, etc.
Autors: Hui Geng;Kevin A. Kwiat;Charles A. Kamhoua;Yiyu Shi;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2018, volume: 37, issue:1, pages: 123 - 132
Publisher: IEEE
 
» On the Achievable Secrecy Diversity of Cooperative Networks With Untrusted Relays
Abstract:
Cooperative relaying is often deployed to enhance the communication reliability (i.e., diversity order) and consequently the end-to-end achievable rate. However, this raises several security concerns when the relays are untrusted, since they may have access to the relayed message. In this paper, we study the achievable secrecy diversity order of cooperative networks with untrusted relays. In particular, we consider a network with an -antenna transmitter (Alice), single-antenna relays, and a single-antenna destination (Bob). We consider the general scenario, where there is no relation between and , and therefore, can be larger than . Alice and Bob are assumed to be far away from each other, and all communication is done through the relays, i.e., there is no direct link. Providing secure communication while enhancing the diversity order has been shown to be very challenging. In fact, it has been shown in the literature that the maximum achievable secrecy diversity order for the adopted system model is one (while using artificial noise jamming). In this paper, we adopt a nonlinear interference alignment scheme that we have proposed recently to transmit the signals from Alice to Bob. We analyze the proposed scheme in terms of the achievable secrecy rate and secrecy diversity order. Assuming Gaussian inputs, we derive an explicit expression for the achievable secrecy rate and show analytically that a secrecy diversity order of up to - an be achieved using the proposed technique. We provide several numerical examples to validate the obtained analytical results and demonstrate the superiority of the proposed technique to its counterparts that exist in the literature.
Autors: Mohaned Chraiti;Ali Ghrayeb;Chadi Assi;Mazen O. Hasna;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2018, volume: 66, issue:1, pages: 39 - 53
Publisher: IEEE
 
» On the Achievable Throughput of Energy-Harvesting Nanonetworks in the Terahertz Band
Abstract:
In this paper, the maximum achievable throughput of electromagnetic nanonetworks in the terahertz (THz) band (0.1–10 THz) is comprehensively investigated. On the one hand, the peculiarities of the THz-band channel are taken into account by capturing the impact of the molecular absorption loss on the signal propagation. On the other hand, a two-state medium access control protocol is utilized to reflect the behavior of energy-harvesting nano-devices with constrained harvesting rate and maximum transmission power . An ad-hoc nanonetwork is considered with identical randomly located nano-devices, and each is capable of utilizing Hz of bandwidth. When the node density of nanonetworks is low, the achievable throughput is , where and refer to the spreading loss coefficient and the molecular absorption loss coefficient. When the node density of nanonetworks is very high, the interference among nano-devices governs the network behavior and the achievable throughput becomes . For both the cases, the upper boundaries of the achievable throughput are analytically derived, and the numerical results are provided. Numerical results illustrate that the molecular ab- orption loss plays the main role when the nanonetwork is sparse, and the interference dominates when the nanonetwork node density is very high.
Autors: Xin-Wei Yao;Chao-Chao Wang;Wan-Liang Wang;Josep Miquel Jornet;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2018, volume: 18, issue:2, pages: 902 - 912
Publisher: IEEE
 
» On the Alternative Vector Potential Formulation of the Sommerfeld Half-Space Problem
Abstract:
We address the non-uniqueness of the vector potential for the Sommerfeld half-space problem with a horizontal Hertzian dipole. In contrast to the classical solution, which utilizes horizontal and vertical components of the vector potential, the formulation presented here employs two horizontal components. In this approach, unlike in the traditional one, the scalar potentials of single-point charges associated with the vertical and horizontal Hertzian dipoles are identical.
Autors: Krzysztof A. Michalski;
Appeared in: IEEE Antennas and Wireless Propagation Letters
Publication date: Jan 2018, volume: 17, issue:1, pages: 54 - 57
Publisher: IEEE
 
» On the Capacity of Wireless Powered Communication Systems Over Rician Fading Channels
Abstract:
In this paper, we consider a point-to-point multi-input multi-output wireless-powered communication system, where the source S is powered by a dedicated power beacon (PB) with multiple antennas. Employing the time splitting protocol, the energy constrained source S first harvests energy through the radio-frequency signals sent by the PB and then uses this energy to transmit information to the destination D. Unlike several prior works, we assume that the energy transfer link is subjected to Rician fading, which is a real fading environment, due to relatively short range power transfer distance and the existence of a strong line of sight path. We present a comprehensive analysis of the achievable ergodic capacity in two scenarios, depending on the availability of channel state information (CSI) at PB, namely, the absence of CSI and partial CSI. For the former case, equal power allocation is used, while for the later one, energy beamforming is used to enhance the energy transfer efficiency. For both the cases, closed-form expressions for the upper and lower bounds of the ergodic capacity are derived. Furthermore, the optimal time split is discussed, and the capacity in the low and high signal-to-noise ratio regimes is studied through simple closed-form expressions. Numerical results and simulations are provided to validate the theoretical analysis. The results show that the Rician factor has a significant impact on the ergodic capacity performance, and this impact strongly depends on the availability of the CSI at the PB.
Autors: Feiran Zhao;Hai Lin;Caijun Zhong;Zoran Hadzi-Velkov;George K. Karagiannidis;Zhaoyang Zhang;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2018, volume: 66, issue:1, pages: 404 - 417
Publisher: IEEE
 
» On the Combination of Double Space Time Transmit Diversity With Spatial Modulation
Abstract:
In this paper, we propose a spatially modulated space-time block coding scheme, called DT-SM, by combining the conventional double space time transmit diversity (DSTTD) with spatial modulation. First, we design a set of four basic spatial constellation (SC) codewords and an extended set of 16 SC codewords for four transmit antennas by using computer search based on the rank and determinant criterion. We then present a generalized algorithm to design SC codewords for an arbitrary number of transmit antennas greater than four. Compared with DSTTD, the proposed scheme attains the same transmit diversity order, while offering higher spectral efficiency. Besides, we derive a union bound for the bit error rate (BER) of the proposed DT-SM scheme in a quasi-static Rayleigh fading channel with spatial correlation. In order to achieve the performance of maximum-likelihood (ML) estimation at reduced detection complexity, we develop a sphere decoder based on the conventional Schnorr-Euchner sphere decoder. BER performance and detection complexity of the DT-SM scheme are evaluated by computer simulations. It is shown that the proposed DT-SM outperforms many existing MIMO and SM-based MIMO schemes at reasonable detection complexity, even in correlated MIMO channels.
Autors: Minh-Tuan Le;Tien-Dong Nguyen;Xuan-Nam Tran;Vu-Duc Ngo;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 170 - 181
Publisher: IEEE
 
» On the Complexity of Bounded View Propagation for Conjunctive Queries
Abstract:
The view propagation problem is a class of view update problem in relational databases  [7] , involving deletion and insertion propagations. Given source database , conjunctive query , view generated by query and a deletion (insertion) on view , deletion (insertion) propagation is to find a side effect free update on such that the deletion (insertion) of from (into) will delete (insert) the intentional ones without resulting in the deletion (insertion) of additional tuples from (into) the view. Generally, such a deletion (insertion) is side effect free. The related data management applications include query result explanation, data debugging, and anonymizing datasets, which rely on understanding how interventions in a database affect the output of a query. View propagation is a natural and typical way to define such interventions, which seems to be well-studied. However, in general, the candidate update on a source database is picked up aimlessly in advance, making the updated database to be very distant from the original one no matter whether it is the maximum one. In this paper, we formally define the bounded view propagation problem, where candidate update is bounded as a subset of potential which is a fixed small tuple set of . We study the complexity of this problem for conjunctive queries, and make contributions to the previous results of the problems of side-effect free deletion propagation. Specifically, our bounded view propagation problem decreases computational complexity regardless of conjunctive query structure. We show the fixed potential is actually a dichotomy for both deletion and insertion propagations, and figure out the results on combined complexity which is neglected previously. Based on our results, for view propagation, we map out a complete picture of the computational complexity h
Autors: Dongjing Miao;Zhipeng Cai;Jianzhong Li;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jan 2018, volume: 30, issue:1, pages: 115 - 127
Publisher: IEEE
 
» On the Construction of LDPC Codes Free of Small Trapping Sets by Controlling Cycles
Abstract:
Low-density parity-check (LDPC) codes exhibit excellent error correcting capability. However, small trapping sets in the Tanner graph are harmful to the iterative decoding algorithm. In this letter, we present a method of constructing girth-eight quasi-cyclic LDPC codes with low error floor by removing the small trapping sets from the Tanner graph. To address this issue, we analyze the relationship between eight-cycles and small trapping sets of Tanner graphs based on fully connected base graphs without parallel edges. We find that if some eight-cycles are not found in the Tanner graphs, any elementary trapping set in the range of and is removed naturally. We also derive a lower bound on the permutation size for the construction of such codes. The experimental simulation shows a favorable error rate performance with lower error floor over additive white Gaussian noise channels.
Autors: Xiongfei Tao;Yufei Li;Yonghe Liu;Zuoqi Hu;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 9 - 12
Publisher: IEEE
 
» On the Contribution to the Field of the Nonphysical Characteristic Modes in Infinite Dielectric Circular Cylinders Under Normal Excitation
Abstract:
Here, a detailed analysis of characteristic modes and fields of an infinite dielectric circular cylinder when computed through the Poggio-Miller–Chang-Harrington–Wu-Tsai formulation is carried out. The purpose is to determine their contribution to the total field, inside and outside the dielectric body and under two possible excitations: incident plane wave or electric line source within the cylinder. The study has been done analytically to provide necessary physical insight of the results obtained. New details about the so-called nonphysical modes are provided. It is found that these modes, that can be neglected outside the dielectric body, do have a significant contribution to the inner field when the excitation source is within the dielectric body. It is concluded that the terms physical and nonphysical characteristic modes should be replaced for radiating and nonradiating characteristic modes.
Autors: Tomás Bernabeu-Jiménez;Alejandro Valero-Nogueira;Felipe Vico-Bondia;Ahmed A. Kishk;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2018, volume: 66, issue:1, pages: 505 - 510
Publisher: IEEE
 
» On the Design of a Long Range WSN for Precision Irrigation
Abstract:
This research presents a WSN computer system model applied to precision irrigation, specifically for conditions in which sensor nodes may be located far from the coordinator. The proposed model is based on a tailored hardware and software aiming to extend both sensor nodes and WSN lifetime. The coordinator is aware of its sensor nodes’ available energy and such feature enables estimating the remaining lifetime of each sensor node. The so-called Sensor nOdes’ system for data acqUisition of Long range (SOUL) is the conceptual model for a sensor node hardware and software system design, concerning energy management and messages grouping, improving both sensor nodes and network lifetime. The sensor nodes were employed to monitor soil moisture and thus the SOUL computer system model was validated in field conditions. Sensor nodes lifetime was increased by 5.7 times when compared with a conventional use.
Autors: Ricardo Godoi Vieira;Adilson Marques da Cunha;Linnyer Beatryz Ruiz;Antonio Pires de Camargo;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2018, volume: 18, issue:2, pages: 773 - 780
Publisher: IEEE
 
» On the Development of a Robust Optical Fiber-Based Level Sensor
Abstract:
A novel optical fiber-based probe was used to determine the fluid level in a nitrate salt up to 400 °C. The probe consisted of a single mode optical fiber and heating element running coaxially, both encapsulated in a protective stainless steel sheath. The temperature was determined continuously along the length of the optical fiber with the use of Rayleigh backscatter based optical frequency domain reflectometry. With the heater activated, the convection coefficient of the surrounding medium defined the axial temperature profile of the probe. The gas-fluid interface was determined by fitting a numerically calculated temperature profile with actual optical fiber data by minimizing the sum of square residuals. The probe was successfully tested over a range of 18 cm, revealing an accuracy of ±1.7 mm and a response time as low as 5.3 s.
Autors: Matthew T. Weathered;Mark H. Anderson;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2018, volume: 18, issue:2, pages: 583 - 588
Publisher: IEEE
 
» On the DoF Region for the Asymmetric MIMO Two-Way X Relay Channel
Abstract:
In this paper, we study the degrees of freedom (DoF) region for the multiple-input multiple-output two-way X relay channel with asymmetric antenna setting. In this channel model, there are two groups of source nodes, each group contains two source nodes, every source node in one group exchanges independent messages with every source node in another group via a common relay node, and each node has a different number of antennas. First, we derive an outer bound of the DoF region by using the cut-set theorem and the genie-message approach. Then, we obtain an inner bound of the DoF region by proposing a new transmission scheme that collectively utilizes antenna deactivation, pairwise signal alignment, cyclic signal alignment, and generalized signal alignment techniques. In the case of symmetric data exchange, our inner bound coincides with the outer bound, and thus, our proposed transmission strategy is optimal. We also obtain the optimal sum DoF for the special case, where the source nodes within a same group are equipped with the same number of antennas. This paper provides new insights for the study of more complicated relay networks.
Autors: Kangqi Liu;Xiaojun Yuan;Meixia Tao;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2018, volume: 66, issue:1, pages: 119 - 132
Publisher: IEEE
 
» On the Double-Generalized Gamma Statistics and Their Application to the Performance Analysis of V2V Communications
Abstract:
Important statistical properties of the double-generalized Gamma (dGG) distribution are studied in this paper. The dGG distribution is suitable for modeling non-homogeneous double-scattering radio propagation fading conditions, which can be frequently observed in vehicle-to-vehicle (V2V) communications. In this context, important statistical metrics for the bivariate dGG distribution, such as the joint probability density function, cumulative distribution function, and the moments, are derived for the first time, while simplified expressions for the corresponding marginal statistical metrics are presented. Moreover, the second-order statistics of this distribution are also analytically studied. The derived analytical framework has been employed to analyze the performance of a transmit antenna selection system operating in V2V communication channels modeled by the dGG distribution. In this scenario, the impact of outdated channel state information (CSI) to the system’s performance is investigated in terms of various metrics, including the level crossing rate and the average fade duration. Furthermore, simplified asymptotic closed-form expressions for the outage probability have been derived to examine the achievable diversity and coding gains. Based on our analysis, insightful discussions are provided. It is shown that the diversity gain is independent from the number of transmit antennas when the available CSI becomes outdated.
Autors: Petros S. Bithas;Athanasios G. Kanatas;Daniel Benevides da Costa;Prabhat K. Upadhyay;Ugo Silva Dias;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2018, volume: 66, issue:1, pages: 448 - 460
Publisher: IEEE
 
» On the Generalization of DIRECTFN for Singular Integrals Over Quadrilateral Patches
Abstract:
A set of fully numerical algorithms for evaluating the 4-D singular integrals arising from Galerkin surface integral equation methods over conforming quadrilateral meshes is presented. This paper is an extension of DIRECTFN, which was recently developed for the case of triangular patches, utilizing in the same fashion a series of coordinate transformations together with appropriate integration reorderings, and is applicable to coincident, edge adjacent, or vertex adjacent elements. The resulting formulas consist of sufficiently smooth kernels and exhibit several favorable characteristics when compared with the vast majority of the methods currently available. More specifically, they can be applied—without modifications—to the following challenging cases: 1) weakly and strongly singular kernels; 2) basis and testing functions of arbitrary order; 3) planar and curvilinear patches; 4) problem-specific Green functions (e.g., expressed in spectral integral form); and 5) spectral convergence to machine precision. Finally, we show that the overall performance of the fully numerical schemes can be further improved by a judicious choice of the integration order for each dimension.
Autors: Alexandra A. Tambova;Mikhail S. Litsarev;Georgy Guryev;Athanasios G. Polimeridis;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2018, volume: 66, issue:1, pages: 304 - 314
Publisher: IEEE
 
» On the Hopping Loss in MIMO Decode-and-Forward Cooperative Relaying
Abstract:
Multi-hop relaying is well known to extend the range of wireless communications. However, the end-to-end performance of the multi-hop relaying channel degrades compared to that observed at the first hop. This performance degradation mainly arises due to: 1) half-duplex loss and 2) hopping or relaying loss. In this paper, we analyze the degradation in outage probability and ergodic capacity due to hopping loss in a multiple-input multiple-output (MIMO) dual-hop decode-and-forward relaying network over Rayleigh fading channels. In particular, we characterize analytically the performance degradation by deriving closed-form approximations of ergodic capacity and outage probability in the single-source single-relay single-user, single-source multiple-relay single-user, and single-source single-relay multiple-user topologies. These approximations also provide insights on how to overcome performance degradations due to hopping loss. Moreover, we show that cooperative relaying schemes can recover a significant portion of the hopping loss.
Autors: Ishtiaq Ahmad;Khoa D. Nguyen;Nick Letzepis;André Pollok;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2018, volume: 66, issue:1, pages: 54 - 63
Publisher: IEEE
 
» On the Hybrid TOA/RSS Range Estimation in Wireless Sensor Networks
Abstract:
Distance estimation, which arises in many applications and especially in range-based localization, is addressed for joint received signal strength (RSS) and time of arrival (TOA) data. A statistical characterization of the joint maximum likelihood estimator, which is unavailable in closed-form, is provided together with a full performance assessment in terms of the actual mean squared error (MSE), in order to establish when hybrid estimation is superior compared to RSS-only or TOA-only estimation. Furthermore, a novel closed-form estimator is proposed based on an ad-hoc relaxation of the likelihood function, which removes the need to adopt iterative methods for hybrid TOA/RSS ranging and strikes a better bias-variance tradeoff for improved performance. A thorough theoretical analysis, corroborated by numerical simulations, shows the effectiveness of the proposed approach, which outperforms state-of-the-art solutions.
Autors: Angelo Coluccia;Alessio Fascista;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 361 - 371
Publisher: IEEE
 
» On the Maximum Number of Bent Components of Vectorial Functions
Abstract:
In this paper, we show that the maximum number of bent component functions of a vectorial function is . We also show that it is very easy to construct such functions. However, it is a much more challenging task to find such functions in polynomial form , where has only a few terms. The only known power functions having such a large number of bent components are , where . In this paper, we show that the binomials also have such a large number of bent components, and these binomials are inequivalent to the monomials if . In addition, the functions have differential properties much better than . We also determine the complete Walsh spectrum of our functions when is odd and .
Autors: Alexander Pott;Enes Pasalic;Amela Muratović-Ribić;Samed Bajrić;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2018, volume: 64, issue:1, pages: 403 - 411
Publisher: IEEE
 
» On the Minimization of Glass-to-Glass and Glass-to-Algorithm Delay in Video Communication
Abstract:
Video cameras are increasingly used to provide real-time feedback in automatic control systems, such as autonomous driving and robotics systems. For such highly dynamic applications, the glass-to-glass (G2G) and glass-to-algorithm (G2A) latencies are critical. In this paper, we analyze the latencies in a point-to-point video transmission system and propose novel frame skipping and preemption approaches to reduce the G2G and G2A delays. We implement the proposed approaches in a prototype that shows significantly reduced G2G and G2A latencies as well as reduced transmission bitrate requirements compared with traditional video transmission schemes. In our low-delay video communication prototype, a VGA resolution video is transmitted with average G2G and G2A delays of 21.2 and 11.5 ms, respectively, with off-the-shelf hardware.
Autors: Christoph Bachhuber;Eckehard Steinbach;Martin Freundl;Martin Reisslein;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jan 2018, volume: 20, issue:1, pages: 238 - 252
Publisher: IEEE
 
» On the Need of Joint Bandwidth and NFV Resource Orchestration: A Realistic 5G Access Network Use Case
Abstract:
5G envisages a “hyper-connected society,” where an enormous number of devices are inter-connected anywhere and at any time. Cloud-enabled radio access networks (RANs) where intelligence is placed in conjunction with the radio heads at the proximity of end users are a promising solution to fulfill the 5G expectations of sub-millisecond latency, huge traffic volumes, and higher data rates. Network functions virtualization (NFV) and software-defined networking (SDN) developments enable end users to access advanced features, such as configurability, automation, scalability, improved resource utilization, and multi tenancy over the cloud-enabled RANs. Management and orchestration techniques are the ultimate factor that determines the effectiveness of the novel SDN/NFV features being introduced. Our focus in this letter is the resource allocation in a realistic cloud-enabled RAN, taking into account the dynamics of ~100,000 persons movement in a crowded event, i.e., a football match. The proposed solution jointly orchestrates NFV and bandwidth resources, as one resource affects the other. Simulation results clearly verify the benefits of the proposed solution over traditional disjoint schemes.
Autors: Jose-Juan Pedreno-Manresa;Pouria Sayyad Khodashenas;Muhammad Shuaib Siddiqui;Pablo Pavon-Marino;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 145 - 148
Publisher: IEEE
 
» On the Optimal Switch Functions for Fast FDTD Monochromatic Lightwave Generation
Abstract:
A smooth and monotone-increasing function is often applied to switch on a monochromatic lightwave source useful for modeling the coherent light interaction with optical and photonic structures by the finite-difference time-domain (FDTD) method. In this letter, the reasoning and guideline of the optimal switch functions for the fast generation of time-harmonic lightwaves in two or three periods were proposed and discussed based on the tradeoff between the higher order smoothness at the two connection points and the smaller average slope in the central segment of switch function in order to suppress the levels of high-frequency components of the impressed source that attribute to the initial transient magnitude deformation and fluctuation. Two candidates for the potentially optimal switch functions that satisfy the criteria are given, and numerical examples with FDTD simulations are presented to verify their superior performances over the conventional Hann function.
Autors: Zhili Lin;Weibin Qiu;Yuntuan Fang;Jixiong Pu;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:1, pages: 115 - 118
Publisher: IEEE
 
» On the Performance of Spatially Correlated Large Antenna Arrays for Millimeter-Wave Frequencies
Abstract:
A spatially correlated large antenna array operating at millimeter-wave (mmWave) frequencies is considered. Based on a Saleh–Valenzuela channel model, closed-form expressions of the 3-D spatial correlation (SC) for wide, narrow, and Von Mises power elevation spectra (PESs) are analytically derived. The effects of the PES on the convergence to massive multiple-input-multiple-output properties are then illustrated by defining and deriving a diagonal dominance metric. Numerically, the effects of antenna element mutual coupling (MC) are shown on the effective SC, eigenvalue structure, and mmWave user rate for different antenna topologies. It is concluded that although MC can significantly reduce SC for side-by-side dipole antenna elements, the change in antenna effective gain (and, therefore, signal-to-noise ratio) caused by MC becomes a dominating effect and ultimately determines the antenna array performance. The user rate of an mmWave system with hybrid beamforming, using an orthogonal matching pursuit (OMP) algorithm, is then shown for different antenna topologies with dipole and cross-polarized (x-pol) antenna elements. It is seen that even for small numbers of radio frequency chains, the OMP algorithm works well relative to the fully digital case for channels with high SC, such as the x-pol antenna array.
Autors: Callum T. Neil;Adrian Garcia-Rodriguez;Peter J. Smith;Pawel A. Dmochowski;Christos Masouros;Mansoor Shafi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2018, volume: 66, issue:1, pages: 132 - 148
Publisher: IEEE
 
» On the Processing of Very High Resolution Spaceborne SAR Data: A Chirp-Modulated Back Projection Approach
Abstract:
A new image formation algorithm is proposed for processing very high resolution spaceborne sliding-spotlight synthetic aperture radar (SAR) data. Because of along-track antenna steering, the Doppler bandwidth of the received SAR data is expanded significantly beyond one pulse repetition frequency interval. Furthermore, the range histories become spatially dependent in both dimensions and cannot be expressed exactly by a hyperbolic model. In our approach, we first reduce the Doppler bandwidth by a novel azimuth dechirp processing method in the range frequency domain. The data are then processed by the standard – algorithm with a fixed effective velocity. Thereafter, the chirp modulation concept is imported to rebuild new data with much shorter apertures. Finally, a standard back-projection algorithm is employed to accumulate the signal pixel by pixel along the newly built aperture. Thus, the balance between processing efficiency and precision can be controlled by adjusting the length of the new apertures. In addition, a more accurate 2-D spectrum derivation is employed to enhance the processing precision, and a novel range-splitting method is presented to accommodate the range dependence of effective velocities. Furthermore, when implementing the back projection, the image grid—the region and granularity level of which are user defined—is placed on the earth’s surface instead of on the slant-range plane, and the routine geometry projection processing thus becomes dispensable.
Autors: Dadi Meng;Chibiao Ding;Donghui Hu;Xiaolan Qiu;Lijia Huang;Bing Han;Jiayin Liu;Ning Xu;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jan 2018, volume: 56, issue:1, pages: 191 - 201
Publisher: IEEE
 
» On the Properties of the Power Systems Nodal Admittance Matrix
Abstract:
This letter provides conditions determining the rank of the nodal admittance matrix, and arbitrary block partitions of it, for connected AC power networks with complex admittances. Furthermore, some implications of these properties concerning Kron reduction and hybrid network parameters are outlined.
Autors: Andreas Martin Kettner;Mario Paolone;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 1130 - 1131
Publisher: IEEE
 
» On the Treatment of Field Quantities and Elemental Continuity in FEM Solutions
Abstract:
As the finite element method (FEM) and the finite volume method (FVM), both traditional and high-order variants, continue their proliferation into various applied engineering disciplines, it is important that the visualization techniques and corresponding data analysis tools that act on the results produced by these methods faithfully represent the underlying data. To state this in another way: the interpretation of data generated by simulation needs to be consistent with the numerical schemes that underpin the specific solver technology. As the verifiable visualization literature has demonstrated: visual artifacts produced by the introduction of either explicit or implicit data transformations, such as data resampling, can sometimes distort or even obfuscate key scientific features in the data. In this paper, we focus on the handling of elemental continuity, which is often only continuous or piecewise discontinuous, when visualizing primary or derived fields from FEM or FVM simulations. We demonstrate that traditional data handling and visualization of these fields introduce visual errors. In addition, we show how the use of the recently proposed line-SIAC filter provides a way of handling elemental continuity issues in an accuracy-conserving manner with the added benefit of casting the data in a smooth context even if the representation is element discontinuous.
Autors: Ashok Jallepalli;Julia Docampo-Sánchez;Jennifer K. Ryan;Robert Haimes;Robert M. Kirby;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 903 - 912
Publisher: IEEE
 
» On Uplink Virtual MIMO with Device Relaying Cooperation Enforcement in 5G Networks
Abstract:
In this paper, a novel protocol is proposed in which mobile terminals (MT) form a virtual Multiple-input Multiple-output (MIMO) uplink by means of device relaying on Device to Device (D2D) tier in 5G Cellular Network. The competitive scenario is considered in which each of the selfish MTs tries to transmit its own data and not relay others’ data in the formed virtual MIMO. The main focus is to design an incentive for MTs to form the virtual MIMO and cooperate in relaying others data. A direct revelation on-line mechanism for the BS is designed, in order to assist forming a stable virtual MIMO. A self-punishment mechanism is also proposed in which MTs autonomously punish malicious MTs that do not cooperate in relaying. We prove that our designed direct revelation on-line mechanism and proposed self-punishment mechanism enforce all-cooperation (all-C) profile as a Nash equilibrium (NE), under uncertainty in the presence of MTs in the formed virtual MIMO. Our simulation results confirm that the proposed protocol, even in the competitive scenario, increases the bit rate and decreases power consumption at the same time. The proposed protocol can improve the energy efficiency up to 35 percent compared to a non-cooperative case, i.e., Single-Input Multiple-Output (SIMO) uplink. Moreover, if the multi-user MIMO transmission is used for the uplink medium access layer, the proposed protocol can improve the energy efficiency up to 42 percent compared to SIMO uplink with multi-user MIMO transmission. Under the proposed OCVM protocol with Shapley value fairness, the price of anarchy reaches to 0.78 in the competitive scenario. In addition, the energy efficiency improvement of our proposed protocol is almost robust to the preferences of MTs. Simulation results show that if BS employs our on-line mechanism and MTs autonomously punish malicious MTs, the malicious MTs cannot gain by defecting from relaying other MTs’ data.
Autors: Mehdi Naderi Soorki;Mohammad Hossein Manshaei;Behrouz Maham;Hossein Saidi;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2018, volume: 17, issue:1, pages: 155 - 168
Publisher: IEEE
 
» On Variability of Renewable Energy and Online Power Allocation
Abstract:
As electric power system operators shift from conventional energy to renewable energy sources, power distribution systems will experience increasing fluctuations in supply. These fluctuations present the need to not only design online decentralized power allocation algorithms, but also characterize how effective they are given fast-changing consumer demand and generation. In this paper, we present an online decentralized dual descent (OD3) power allocation algorithm and determine (in the worst case) how much of observed social welfare can be explained by fluctuations in generation capacity and consumer demand. Convergence properties and performance guarantees of the OD3 algorithm are analyzed by characterizing the difference between the online decision and the optimal decision. We demonstrate validity and accuracy of the theoretical results in the paper through numerical experiments using real power generation data.
Autors: Chinwendu Enyioha;Sindri Magnússon;Kathryn Heal;Na Li;Carlo Fischione;Vahid Tarokh;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 451 - 462
Publisher: IEEE
 
» On-Chip Interconnect Conductor Materials for End-of-Roadmap Technology Nodes
Abstract:
A comprehensive review of challenges and potential solutions associated with the impact of downscaling of integrated circuit (IC) feature sizes on on-chip interconnect materials is presented. The adoption of Moore's Law has led to developments and manufacturing of transistors with nanoscale dimensions, faster switching speeds, lower power consumption, and lower costs in recent generations of IC technology nodes. However, shrinking dimensions of wires connecting transistors have resulted in degradations in both performance and reliability, which in turn limit chip speed and lifetime. Therefore, to sustain the continuous downward scaling, alternative interconnect conductor materials to replace copper (Cu) and tungsten (W) must be explored to meet and overcome these challenges.
Autors: Anshul A. Vyas;Changjian Zhou;Cary Y. Yang;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2018, volume: 17, issue:1, pages: 4 - 10
Publisher: IEEE
 
» On-Chip SOI Delay Line Bank for Optical Buffers and Time Slot Interchangers
Abstract:
We demonstrate integrated silicon-on-insulator (SOI) spiral waveguides with record-high 2.6-ns/mm2 on-chip delay efficiency performing as delay bank stage in variable optical delay buffering and time-slot interchanger applications with 10-Gb/s optical packets. The micro-scale SOI chip comprises three integrated waveguide delay elements of different lengths, providing variable delays of 6.5, 11.3, and 17.2 ns, respectively. Utilizing two semiconductor optical amplifier Mach-Zehnder interferometer wavelength converters and on-chip packet delay, error-free on-chip variable delay buffering from 6.5 to 17.2 ns and successful time-slot interchanging for 10-Gb/s optical packets are presented.
Autors: M. Moralis-Pegios;G. Mourgias-Alexandris;N. Terzenidis;M. Cherchi;M. Harjanne;T. Aalto;A. Miliou;N. Pleros;K. Vyrsokinos;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:1, pages: 31 - 34
Publisher: IEEE
 
» One-Dimensional Nonlinear Model for Producing Chaos
Abstract:
Motivated by the concept of circuit design in digital circuit, this paper proposes a one-dimensional (1D) nonlinear model (1D-NLM) for producing 1D discrete-time chaotic maps. Our previous works have designed four nonlinear operations of generating new chaotic maps. However, they focus only on discussing individual nonlinear operations and their properties, but fail to consider their relationship among these operations. The proposed 1D-NLM includes these existing nonlinear operations, develops two new nonlinear operations, discusses their relationship among different nonlinear operations, and investigates the properties of different combinations of these operations. To show the effectiveness of 1D-NLM in generating new chaotic maps, as examples, we provide four new chaotic maps and study their dynamics properties from following three aspects: equilibrium point, stability, and bifurcation diagram. Performance evaluations are provided using the Lyapunov exponent, Shannon entropy, correlation dimension, and initial state sensitivity. The evaluation results show that these new chaotic maps have more complex chaotic behaviors than existing ones. To demonstrate the performance of 1D-NLM in practical applications, we use a pseudo-random number generator (PRNG) to compare new and existing chaotic maps. The randomness test results indicate that new chaotic map generated by 1D-NLM shows better performance than existing ones in designing PRNG.
Autors: Zhongyun Hua;Yicong Zhou;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2018, volume: 65, issue:1, pages: 235 - 246
Publisher: IEEE
 
» One-Way Electromagnetic Mode Guided by the Mechanism of Total Internal Reflection
Abstract:
One-way electromagnetic mode that is guided by the mechanism of total internal reflection (TIR) can be realized in terahertz regime. In the optical system consisting of a dielectric layer sandwiched between magnetized semiconductor and metal, the one-way TIR mode can be immune to backscattering at imperfections. This mode possesses a broad band when high-order TIR modes are suppressed in the relevant semiconductor bandgap. Furthermore, it is shown that compared with one-way surface magnetoplasmons, the one-way TIR mode can more effectively match with the fundamental mode of conventional optical waveguide.
Autors: Linfang Shen;Jie Xu;Yun You;Kai Yuan;Xiaohua Deng;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:2, pages: 133 - 136
Publisher: IEEE
 
» Online Estimation of Steady-State Load Models Considering Data Anomalies
Abstract:
Several techniques have been developed to estimate the load parameters in power systems. Most of the existing algorithms mainly focus on estimating the parameters for offline studies. With on-going smart grid development, high-resolution data at faster rates are available to allow estimation of load parameters in real time. This paper addresses the challenges in online estimation of the load parameters using phasor measurement unit data. A novel adaptive search-based algorithm to estimate load model parameters is presented here. In this paper, a static load model is used with the Z (constant impedance), I (constant current), and P (constant power) components of the load. Developed estimation algorithms for the ZIP parameter estimation are validated using the IEEE 14-bus system and data provided by the industry collaborators. Simulation results demonstrate the accurate estimation of the ZIP load model using the developed method. Also, various techniques to eliminate anomalies in the input data for accurate estimation of the load parameters have been presented in this paper.
Autors: Tushar;Shikhar Pandey;Anurag K. Srivastava;Penn Markham;Mahendra Patel;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2018, volume: 54, issue:1, pages: 712 - 721
Publisher: IEEE
 
» Online Multi-Object Tracking Using Hierarchical Constraints for Complex Scenarios
Abstract:
Online multi-object tracking (MOT) in an intelligent vehicle platform aims at locating the surrounding objects in real time, which remains far from being solved in complex scenarios, due to various motion patterns of tracked objects and severe occlusions caused by cluttered background or other objects. In this paper, we establish a unified online MOT framework for complex scenarios that employs a hierarchical model to improve the solution of data association, termed hierarchical MOT (HMOT). Incorporating the multiple Gaussians uncertainty theory into the individual motion model for each target followed by imposing interaction constraint to re-associate the tracklets with lower confidence leads our algorithm to achieve accurate multi-object tracking. With such a model, individual objects are not only more precisely associated across frames, but also dynamically constrained with each other in a global manner. Experiments on challenging data sets verify the performance of the proposed HMOT approach over the other state-of-the-art MOT methods.
Autors: Junying Liu;Xianbin Cao;Yan Li;Baochang Zhang;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2018, volume: 19, issue:1, pages: 151 - 161
Publisher: IEEE
 
» Online Tool Wear Monitoring Via Hidden Semi-Markov Model With Dependent Durations
Abstract:
The tool wear monitoring (TWM) system that could estimate tool wear conditions and predict remaining useful life (RUL) is important to meet the high precision requirement and improve productivity in automated machining. Due to its good properties in representing nonstationary and complex physical process, hidden semi-Markov Model (HSMM) is adapted to model the progressive tool wear in this paper. In order to describe the time-variant transition probability of tool wear states and the state duration dependency, the HSMM is improved by learning the duration parameters and RUL distribution database. The Forward algorithm is utilized for online tool wear estimation and remaining life prognosis, and an online implementation approach is developed to reduce computational cost. Experimental results show that the approach is effective and the proposed method of duration dependency modeling leads to more accurate TWM in high speed milling.
Autors: Kunpeng Zhu;Tongshun Liu;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Jan 2018, volume: 14, issue:1, pages: 69 - 78
Publisher: IEEE
 
» Open vs. Closed Shapes: New Perceptual Categories?
Abstract:
Effective communication using visualization relies in part on the use of viable encoding strategies. For example, a viewer's ability to rapidly and accurately discern between two or more categorical variables in a chart or figure is contingent upon the distinctiveness of the encodings applied to each variable. Research in perception suggests that color is a more salient visual feature when compared to shape and although that finding is supported by visualization studies, characteristics of shape also yield meaningful differences in distinctiveness. We propose that open or closed shapes (that is, whether shapes are composed of line segments that are bounded across a region of space or not) represent a salient characteristic that influences perceptual processing. Three experiments were performed to test the reliability of the open/closed category; the first two from the perspective of attentional allocation, and the third experiment in the context of multi-class scatterplot displays. In the first, a flanker paradigm was used to test whether perceptual load and open/closed feature category would modulate the effect of the flanker on target processing. Results showed an influence of both variables. The second experiment used a Same/Different reaction time task to replicate and extend those findings. Results from both show that responses are faster and more accurate when closed rather than open shapes are processed as targets, and there is more processing interference when two competing shapes come from the same rather than different open or closed feature categories. The third experiment employed three commonly used visual analytic tasks - perception of average value, numerosity, and linear relationships with both single and dual displays of open and closed symbols. Our findings show that for numerosity and trend judgments, in particular, that different symbols from the same open or closed feature category cause more perceptual interferen- e when they are presented together in a plot than symbols from different categories. Moreover, the extent of the interference appears to depend upon whether the participant is focused on processing open or closed symbols.
Autors: David Burlinson;Kalpathi Subramanian;Paula Goolkasian;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 574 - 583
Publisher: IEEE
 
» OpenSARShip: A Dataset Dedicated to Sentinel-1 Ship Interpretation
Abstract:
With the rapid growth of Sentinel-1 synthetic aperture radar (SAR) data, how to exploit Sentinel-1 imagery and achieve effective and robust marine surveillance are crucial problems. In this paper, we present the OpenSARShip, a dataset dedicated to Sentinel-1 ship interpretation. The OpenSARShip, providing 11 346 SAR ship chips integrated with automatic identification system messages, owes five essential properties: specificality, large scale, diversity, reliability, and public availability. These properties make sure that the OpenSARShip achieves its objectives. The first is to provide researchers a benchmark dataset to develop applicable and adaptive ship interpretation algorithms and push the performance ceilings of data analysis. The other is to provide a dataset for performing application-oriented quality assessment for Sentinel-1 imagery, which can boost their applications in a targeting way. The construction and the organization of the OpenSARShip are discussed, which show the inside of the dataset and ensure the essential properties. The elaborate geometric and scattering analyses, the benchmark for classification, and the imagery applicability assessment by using the OpenSARShip all demonstrate the applicability and potential of the dataset.
Autors: Lanqing Huang;Bin Liu;Boying Li;Weiwei Guo;Wenhao Yu;Zenghui Zhang;Wenxian Yu;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2018, volume: 11, issue:1, pages: 195 - 208
Publisher: IEEE
 
» Operation and Starting of PAM Motors Using Vacuum Contactors
Abstract:
Pole amplitude modulation (PAM) motor is a single-winding two speed motor used for induced draft fans. Its cost is much less than that of an adjustable speed drive motor. This paper is prompted by a rigorous study that was undertaken to replace an existing oil filled, leaky, transfer-switch type, two-speed motor starter, with an adjunct of tens of hard wired timers in a utility installation. The paper describes the fundamental operation of a PAM motor, different torque speed and thermal withstand characteristics at two speeds, and design of an alternate starter using conventional vacuum contactors with modern multifunction microprocessor relays to provide effective protection during normal two-speed operation and starting.
Autors: J. C. Das;Kevin Lancaster;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2018, volume: 54, issue:1, pages: 916 - 922
Publisher: IEEE
 
» Opportunistic Relaying and Random Linear Network Coding for Secure and Reliable Communication
Abstract:
Opportunistic relaying has the potential to achieve full diversity gain, while random linear network coding (RLNC) can reduce latency and energy consumption. In recent years, there has been a growing interest in the integration of both schemes into wireless networks in order to reap their benefits, while considering security concerns. This paper considers a multi-relay network, where relay nodes employ RLNC to encode confidential data and transmit coded packets to a destination in the presence of an eavesdropper. Four relay selection protocols are studied covering a range of network capabilities, such as the availability of the eavesdropper’s channel state information or the possibility to pair the selected relay with a node that intentionally generates interference. For each case, expressions for the probability that a coded packet will not be recovered by a receiver, which can be either the destination or the eavesdropper, are derived. Based on those expressions, a framework is developed that characterizes the probability of the eavesdropper intercepting a sufficient number of coded packets and partially or fully recovering the confidential data. Simulation results confirm the validity and accuracy of the theoretical framework and unveil the security-reliability trade-offs attained by each RLNC-enabled relay selection protocol.
Autors: Amjad Saeed Khan;Ioannis Chatzigeorgiou;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 223 - 234
Publisher: IEEE
 
» Optical Modulation and Antialiasing Methods for Experimental Verification of Sensor Signal Integrity
Abstract:
In this paper, the use of laser modulation for characterizing the sensitivity of infrared sensors and autonomously adjusting frame rates are discussed. Lasers modulated at frequencies near the frame rate of the sensor under test demonstrated a more significant effect than modulation frequencies further from the frame rate. A method to quantify the effectiveness of a particular laser modulation frequency was developed. Experimental runs with and without laser tracking are compared in order to demonstrate how the laser affects the tracking algorithms of the sensor. The effect of the relationship between the modulation frequency and the frame rate on the sensor’s accuracy is also determined. An algorithm was developed to improve a sensor’s ability to detect signals modulated at its frame rate. The paper concludes with discussions on applications of these results to commonly available sensor systems.
Autors: Frances Bodrucki;Andrew Hill;Justin Davis;John Cordell;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2018, volume: 67, issue:1, pages: 101 - 106
Publisher: IEEE
 
» Optical Sectioning Tomographic Reconstruction of Three-Dimensional Flame Temperature Distribution Using Single Light Field Camera
Abstract:
The temperature measurement has great significance for the combustion diagnostics and the study of flame characteristics. In this paper, an optical sectioning tomographic (OST) technique for 3-D flame temperature measurement combined with light field imaging is proposed. First, the fundamental principle of light field OST is introduced in detail. Then, to determine the refocused depth, the point spread functions of the light field camera, and the relationship between the radiation intensity of flame and image gray value, the calibration works are carried out. Furthermore, the images of different sections of flame are acquired by the digital refocusing technology, and then the high-precision and real-time radiation intensity distribution of each section can be reconstructed using a tomographic reconstruction algorithm. Finally, in combination with the relationship between the image gray value and radiation intensity of flame, the 3-D flame temperature distribution can be calculated. The flame experiments of a candle and a single biomass particle in a fluidized bed under oxy-combustion conditions are performed to evaluate the light field OST system. Results show that the reconstructed results are in good agreement with the temperature distribution of the combustion flame. Compared with the traditional optical sectioning tomographic techniques, the light field OST has the advantages of simplicity of measurement system and fast response, and being suitable for 3-D temperature measurement of turbulent flame.
Autors: Wenchao Zhao;Biao Zhang;Chuanlong Xu;Lunbo Duan;Shimin Wang;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2018, volume: 18, issue:2, pages: 528 - 539
Publisher: IEEE
 
» Optical Wireless MIMO Experiments in an Industrial Environment
Abstract:
This paper reports on a field trial in a robotic manufacturing cell. Channel measurements and transmission experiments were conducted, assisting the development of a light-emitting diode-based optical wireless communication (OWC) system tailored for the needs of industrial wireless applications. These are moderate data rates, reliability, and low latency. Since dedicated radio spectrum is hardly available, the usage of light is an interesting alternative. Due to its spatial confinement, OWC links provide enhanced security and are difficult to jam from outside a building—a particularly interesting property for industrial applications. We performed broadband distributed multiple-input multiple-output (MIMO) channel measurements in a manufacturing cell. Results confirm that the signal-to-noise ratio is sufficient if a line-of-sight (LOS) is available and bandwidth is limited to a few megahertz. However, small movements and rotations may lead to sudden fades of 10–20 dB, when an LOS is blocked. To improve reliability, antenna diversity concepts are applied. Results show that for reliable communication, MIMO diversity schemes are indispensable as it increases the probability of a free LOS significantly. Based on these insights, we suggest an OWC design tailored to industrial wireless applications.
Autors: Pablo Wilke Berenguer;Dominic Schulz;Jonas Hilt;Peter Hellwig;Gerhard Kleinpeter;Johannes K. Fischer;Volker Jungnickel;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2018, volume: 36, issue:1, pages: 185 - 193
Publisher: IEEE
 
» Optimal Code Partitioning Over Time and Hierarchical Cloudlets
Abstract:
This letter proposes a task scheduling scheme designed for code partitioning over time and the hierarchical cloudlets in a mobile edge network. To this end, we define the so called energy-time cost parameters to optimally schedule tasks over time and hierarchical cloudlet locations. Accordingly, we investigate two different optimization scenarios. In particular, the first scenario aims at finding the optimal task scheduling for given radio parameters. In the second scenario, we carry out the optimization of both the task scheduling and the mobile device’s transmission power. More importantly, we show that by adopting the proposed code partitioning scheme in this letter, the transmission power optimization problem becomes a disjoint problem from the task scheduling problem.
Autors: Abbas Kiani;Nirwan Ansari;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 181 - 184
Publisher: IEEE
 
» Optimal Combining for Optical Wireless Systems With Amplification: The $chi ^{2}$ Noise Regime
Abstract:
We present novel analytical results on the optimal combiner (OC) for pre-amplified optical wireless receivers under chi-squared noise. The results show that the OC architecture that minimizes the average bit-error rate (BER) is determined by the level of the signal-spontaneous beating noise. Moreover, the OC provides increased gain to the diversity branches with the higher energies, up to the point where the beating noise becomes detrimental to the BER. The performance of the OC is simulated for practical receiver arrangements and it is shown that it performs better than the maximal-ratio and equal-gain combiners. The performance improvement amounts to an energy gain of less than 1 dB for implementations that utilize narrow optical filters and a modest number of diversity branches.
Autors: Konstantinos Yiannopoulos;Nikos C. Sagias;Anthony C. Boucouvalas;Kostas Peppas;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:1, pages: 119 - 122
Publisher: IEEE
 
» Optimal Cross-Layer-Based Asymmetric Resource Allocation for Multidestination Relay Systems
Abstract:
A cross-layer based asymmetric resource allocation strategy for multi-destination relay systems in cellular downlink is proposed in this paper. Existing cross-layer schemes on relay networks are based on symmetric resource allocation (RA) where the transmit duration is assumed to be symmetric between base station to relay station (RS) and RS to mobile station links. This may not be realistic and hence our proposed model considers an asymmetric RA (ARA) in which the transmit durations are asymmetric. Very little work has been done in asymmetric resource allocation and many have failed to consider the queue stability and quality of service (QoS) requirements. Packet length ratio is also ignored in many of these works. In this paper, maximum delay threshold, minimum data rate requirement and zero overflow are considered as QoS requirements. This paper evolves an optimal cross-layer based ARA taking into account the above-mentioned factors. Simulation results are also verified in a cellular testbed which shows that the proposed ARA serves the edge users satisfactorily. Cellular parameters, such as blocking ratio, operating expenditure, electromagnetic pollution index, and QoS assurance, are evaluated and compared.
Autors: L. Senthilkumar;M. Meenakshi;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 250 - 265
Publisher: IEEE
 
» Optimal Energy Management and Velocity Control of Hybrid Electric Vehicles
Abstract:
An assessment study of a novel approach is presented that combines discrete state-space Dynamic Programming and Pontryagin's Maximum Principle for online optimal control of hybrid electric vehicles (HEV). In addition to electric energy storage, engine state and gear, kinetic energy, and travel time are considered states in this paper. After presenting the corresponding model using a parallel HEV as an example, a benchmark method with Dynamic Programming is introduced which is used to show the solution quality of the novel approach. It is illustrated that the proposed method yields a close-to-optimal solution by solving the optimal control problem over one hundred thousand times faster than the benchmark method. Finally, a potential online usage is assessed by comparing solution quality and calculation time with regard to the quantization of the state space.
Autors: Stephan Uebel;Nikolce Murgovski;Conny Tempelhahn;Bernard Bäker;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2018, volume: 67, issue:1, pages: 327 - 337
Publisher: IEEE
 
» Optimal Joint Energy and Secondary Regulation Reserve Hourly Scheduling of Variable Speed Pumped Storage Hydropower Plants
Abstract:
This paper presents a mixed integer linear programming model for the hourly energy and secondary regulation reserve scheduling of a price-taker and closed-loop variable speed pumped-storage hydropower plant, considering the energy losses due to the use of electronic frequency converters. The plant participates in the day-ahead energy market and in the secondary regulation service of the Iberian electric power system. The model is utilised to compare the income of the plant with and without considering the variable speed technology, with synchronous or asynchronous machines, with and without bypassing the frequency converter in generating mode, and with and without perfect information of the electric power system data. Numerical testing results demonstrate that the operation with the variable speed technology could help notably to enlarge the income of the power plant and that the secondary regulation reserve market might be the main source of revenue for the power plant.
Autors: Manuel Chazarra;Juan Ignacio Pérez-Díaz;Javier García-González;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 103 - 115
Publisher: IEEE
 
» Optimal Operation Control for Multiple BESSs of a Large-Scale Customer Under Time-Based Pricing
Abstract:
This paper presents an online optimal operation framework for multiple battery energy storage systems (BESSs) of a large-scale customer under time-based pricing. Many publications have been reported on optimal battery operation techniques but most of them were analyzed in a simulation environment or a specifically designed test bed. However, this paper focuses on implementing the proposed scheme into actual multiple battery storage units and investigating the performance during long-term field operation. The operation framework consists of two levels: optimal scheduling and real-time dispatch. The optimal scheduling is calculated every hour, using a model predictive control based nonlinear optimization model, to minimize the daily electricity usage cost while regulating the peak. The real-time dispatch determines final commands to multiple battery systems by monitoring the system state and checking for any violations of the operation constraints. The two-level control scheme was designed to handle uncertainty in forecast load and estimated state-of-charge levels of batteries. The operation method was applied into the energy management system supervising one lithium-polymer BESS and two lead-acid BESSs of an industrial site. Comprehensive field operation results prove the reliability and effectiveness of the optimal operation framework.
Autors: Seul-Ki Kim;Jong-Yul Kim;Kyeong-Hee Cho;Gilsung Byeon;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 803 - 816
Publisher: IEEE
 
» Optimal Power Control for Transmitting Correlated Sources With Energy Harvesting Constraints
Abstract:
We investigate the weighted-sum distortion minimization problem in transmitting two correlated Gaussian sources over Gaussian channels using two energy harvesting nodes. To this end, we develop off-line and online power control policies to optimize the transmit power of the two nodes. In the off-line case, we cast the problem as a convex optimization and investigate the structure of the optimal solution. We also develop a generalized waterfilling-based power allocation algorithm to obtain the optimal solution efficiently. For the online case, we quantify the distortion of the system using a cost function and show that the expected cost equals the expected weighted-sum distortion. Based on Banach’s fixed point theorem, we further propose a geometrically converging algorithm to find the minimum cost via simple iterations. Simulation results show that our online power control outperforms the greedy power control where each node uses all the available energy in each slot and also performs close to that of the proposed off-line power control. Moreover, the performance of our off-line power control almost coincides with the performance limit of the system.
Autors: Yunquan Dong;Zhi Chen;Jian Wang;Byonghyo Shim;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 461 - 476
Publisher: IEEE
 
» Optimal Reactive Power Flow of Interconnected Power System Based on Static Equivalent Method Using Border PMU Measurements
Abstract:
A new static equivalent method using border PMU measurements is proposed to effectively retain various voltage and reactive power support characteristics of external network without real-time synchronous information of the entire external system. Based on the proposed method, a set of equivalent criteria is developed to determine whether the simplest and the most widely used PV/PQ equivalence is still appropriate. Based on the proposed equivalent method and criteria, we establish a new equivalent optimal reactive power flow model, which can achieve high calculation accuracy for interconnected power systems. The simulation results of the IEEE 39-bus system and an actual 661-bus system demonstrate the accuracy and effectiveness of the proposed method, criteria, and model.
Autors: Juan Yu;Wei Dai;Wenyuan Li;Xuan Liu;Juelin Liu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 421 - 429
Publisher: IEEE
 
» Optimal Reception Delay in Diffusion-Based Molecular Communication
Abstract:
This letter proposes a simple and novel method for mitigating inter-symbol interference (ISI) in molecular communication via diffusion (MCvD). In MCvD applications, the messenger molecules released from the transmitter need some time to reach the receiver. Therefore, the molecules absorbed at the beginning of a transmission interval can only belong to the previous transmissions. Therefore, if a receiver shifts its absorption interval, ISI can be potentially reduced. We find the optimal delay time that the receiver shifts its absorption interval both numerically and analytically to minimize the ISI in the channel. We demonstrate the improved performance of the proposed shift- method in molecular communication over conventional concentration shift keying modulation. The major benefits of the proposed method are its simplicity and applicability to many other schemes in the literature.
Autors: Bayram Cevdet Akdeniz;Ali Emre Pusane;Tuna Tugcu;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 57 - 60
Publisher: IEEE
 
» Optimal Segmentation of High-Resolution Remote Sensing Image by Combining Superpixels With the Minimum Spanning Tree
Abstract:
Image segmentation is the foundation of object-based image analysis, and many researchers have sought optimal segmentation results. The initial image oversegmentation and the optimal segmentation scale are two vital factors in high spatial resolution remote sensing image segmentation. With respect to these two issues, a novel image segmentation method combining superpixels with a minimum spanning tree is proposed in this paper. First, the image is oversegmented using a simple linear iterative clustering algorithm to obtain superpixels. Then, the superpixels are clustered by regionalization with a dynamically constrained agglomerative clustering and partitioning (REDCAP) algorithm using the initial number of segments, and the local variance (LV) and the rate of LV change (ROC-LV) indicator diagrams corresponding to the number of segments are obtained. The suitable number of image segments is determined according to the LV and ROC-LV indicator diagrams corresponding to the number of segments. Finally, the superpixels are reclustered using the REDCAP algorithm based on the suitable number of image segments to obtain the image segmentation result. Through two sets of experiments, the proposed method is compared with two other segmentation algorithms. The experimental results show that the proposed method outperforms the others and obtains good image segmentation results.
Autors: Mi Wang;Zhipeng Dong;Yufeng Cheng;Deren Li;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jan 2018, volume: 56, issue:1, pages: 228 - 238
Publisher: IEEE
 
» Optimal Sensor Placement for Monitoring of Spatial Networks
Abstract:
The problem of optimal placement of sensors for monitoring a spatial network (e.g., a road network with moving ground targets or intruders) is considered in this paper. In particular, the optimization of locations of a set of sensors (that can each obtain measurements in a local region around the sensor location) is considered so as to maximize an overall sensor coverage metric defined over the spatial network. The sensor coverage optimality metric for spatial network coverage is based on a novel formulation of a sensor influence wave based on a spatiotemporal model of the measurement reach of a set of sensors given a spatial network topology, a probabilistic model of target movements on the network, and spatial weight maps that model the relative importance/utility of different locations in the spatial region. The sensor placement optimization is based on an iterative genetic algorithm for the optimization of a scalar metric computed from the spatial integration of the sensor influence wave. The efficacy of the proposed approach is demonstrated through simulation studies for several road network geometries.

Note to Practitioners—This paper considers the problem of finding optimal locations for sensors for monitoring a spatial network for moving targets (e.g., a road network with moving ground targets or intruders). Sensor-based monitoring of a spatial region is relevant in a variety of applications (including, in general, such diverse application areas as traffic monitoring in transportation applications, intruder monitoring, surveillance, power systems monitoring, structural health monitoring, etc). This paper offers two primary novel aspects: an optimality metric formulation for target monitoring effectiveness on spatial networks and an iterative genetic algorithm-based method for optimization of the sensor placement configuration. The proposed approach enables addressing of multiple spatial criteria within a unified fra- ework, including the probabilistic characterizations of spatial target movements over the network and the models of relative importance/utility of different locations/areas in the spatial region.

Autors: Prashanth Krishnamurthy;Farshad Khorrami;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2018, volume: 15, issue:1, pages: 33 - 44
Publisher: IEEE
 
» Optimal Synchronization of Heterogeneous Nonlinear Systems With Unknown Dynamics
Abstract:
Optimal output synchronization of multi-agent leader–follower systems with unknown nonlinear dynamics is considered. The agents are assumed heterogeneous so that the dynamics may be nonidentical. A distributed observer is designed to estimate the leader state for each agent. A discounted performance function is defined for each agent, and an augmented Hamilton–Jacobi–Bellman (HJB) equation is derived to find its minimal value. The HJB solution depends on the trajectories of the local state and the distributed observer state. A control protocol based on the HJB solution assures that the synchronization error goes to zero locally asymptotically fast for all agents. The proposed approach has two main advantages compared to standard output synchronization methods. First, it is optimal in the sense that it not only makes the steady-state synchronization error zero, but also minimizes the transient error. Second, it does not require the explicit solution to the output regulator equations, though the HJB solutions implicitly provide optimal solutions to them. Finally, a reinforcement learning technique is used to learn the optimal control protocol for each agent without requiring any knowledge of the agents or the leader dynamics. Simulation studies on a notional multi-agent system validate the proposed approach.
Autors: Hamidreza Modares;Frank L. Lewis;Wei Kang;Ali Davoudi;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2018, volume: 63, issue:1, pages: 117 - 131
Publisher: IEEE
 
» Optimal Wind Farm Allocation in Multi-Area Power Systems Using Distributionally Robust Optimization Approach
Abstract:
This paper presents a distributionally robust planning model to determine the optimal allocation of wind farms in a multi-area power system, so that the expected energy not served (EENS) is minimized under uncertain wind power and generator forced outages. Unlike conventional stochastic programming approaches that rely on detailed information of the exact probability distribution, the proposed method attempts to minimize the expectation term over a collection of distributions characterized by accessible statistical measures, so it is more practical in cases where the detailed distribution data is unavailable. This planning model is formulated as a two-stage problem, where the wind power capacity allocation decisions are determined in the first stage, before the observation of uncertainty outcomes, and operation decisions are made in the second stage under specific uncertainty realizations. In this paper, the second-stage decisions are approximated by linear decision rule functions, so that the distributionally robust model can be reformulated into a tractable second-order cone programming problem. Case studies based on a five-area system are conducted to demonstrate the effectiveness of the proposed method
Autors: Fahad Alismail;Peng Xiong;Chanan Singh;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 536 - 544
Publisher: IEEE
 
» Optimization for Maximizing Sum Secrecy Rate in MU-MISO SWIPT Systems
Abstract:
In this paper, we consider the sum secrecy rate maximization problem in multiuser multiple-input single-output (MU-MISO) systems in the presence of multiple energy harvesters (EHs) which also have potential to wire-tap the information users (IUs). To facilitate delivering secure information to the IUs and increase the total harvested energy by the EHs simultaneously, we optimize the transmit beamforming vectors to direct the information signals toward the IUs and artificial noise (AN) toward the EHs. We assume that each EH relies on itself to decode the information signal intended for an individual IU. Therefore, the corresponding problem is to maximize the worst-case sum secrecy rate under transmit power and energy harvesting constraints. The problem is optimally solved by transforming it into a convex iterative program using a change of variables, semi-definite relaxation (SDR), and linearization of quadratic terms. We prove that rank-one optimal solutions for the IUs beamforming covariance matrices can be obtained from the optimal relaxed unconstrained solution. Also, we provide three suboptimal solutions based on null space projection and power control of the beamforming vectors for the low and high harvested energy constrained regions. A special case of cooperative EHs in which the EHs can collaboratively cancel the signal of all IUs except the one they intend to eavesdrop is also investigated, and the optimal solution is derived in a comparable way as in noncooperative EHs case. Our simulation results reveal an understanding of how the tradeoff between the AN and information signal can jointly improve both the sum secrecy rate and the total harvested energy. We also show that, within the low total harvested energy region, the suboptimal solution in which the AN is projected in the null space of the IUs channels outperforms the suboptimal solution which ignores AN alignment at the IUs, and vice versa over the high total harvested energy region; and- the suboptimal solution that combines both of them achieves close to optimal performance.
Autors: Mahmoud Alageli;Aissa Ikhlef;Jonathon Chambers;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2018, volume: 67, issue:1, pages: 537 - 553
Publisher: IEEE
 
» Optimization of Coil Element Configurations for a Matrix Gradient Coil
Abstract:
Recently, matrix gradient coils (also termed multi-coils or multi-coil arrays) were introduced for imaging and B0 shimming with 24, 48, and even 84 coil elements. However, in imaging applications, providing one amplifier per coil element is not always feasible due to high cost and technical complexity. In this simulation study, we show that an 84-channel matrix gradient coil (head insert for brain imaging) is able to create a wide variety of field shapes even if the number of amplifiers is reduced. An optimization algorithm was implemented that obtains groups of coil elements, such that a desired target field can be created by driving each group with an amplifier. This limits the number of amplifiers to the number of coil element groups. Simulated annealing is used due to the NP-hard combinatorial nature of the given problem. A spherical harmonic basis set up to the full third order within a sphere of 20-cm diameter in the center of the coil was investigated as target fields. We show that the median normalized least squares error for all target fields is below approximately 5% for 12 or more amplifiers. At the same time, the dissipated power stays within reasonable limits. With a relatively small set of amplifiers, switches can be used to sequentially generate spherical harmonics up to third order. The costs associated with a matrix gradient coil can be lowered, which increases the practical utility of matrix gradient coils.
Autors: Stefan Kroboth;Kelvin J. Layton;Feng Jia;Sebastian Littin;Huijun Yu;Jürgen Hennig;Maxim Zaitsev;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2018, volume: 37, issue:1, pages: 284 - 292
Publisher: IEEE
 
» Optimization of Error-Bounded Lossy Compression for Hard-to-Compress HPC Data
Abstract:
Since today's scientific applications are producing vast amounts of data, compressing them before storage/transmission is critical. Results of existing compressors show two types of HPC data sets: highly compressible and hard to compress. In this work, we carefully design and optimize the error-bounded lossy compression for hard-to-compress scientific data. We propose an optimized algorithm that can adaptively partition the HPC data into best-fit consecutive segments each having mutually close data values, such that the compression condition can be optimized. Another significant contribution is the optimization of shifting offset such that the XOR-leading-zero length between two consecutive unpredictable data points can be maximized. We finally devise an adaptive method to select the best-fit compressor at runtime for maximizing the compression factor. We evaluate our solution using 13 benchmarks based on real-world scientific problems, and we compare it with 9 other state-of-the-art compressors. Experiments show that our compressor can always guarantee the compression errors within the user-specified error bounds. Most importantly, our optimization can improve the compression factor effectively, by up to 49 percent for hard-to-compress data sets with similar compression/decompression time cost.
Autors: Sheng Di;Franck Cappello;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2018, volume: 29, issue:1, pages: 129 - 143
Publisher: IEEE
 
» Optimization of MV Distribution System Designs
Abstract:
This paper will present a new approach that is advantageous to medium-voltage (MV) distribution design configurations for large industrial and power distribution system configurations [specifically main-tie-main (MTM)] for large industrial and power station installations. Sixty years of traditional low-cost design approaches (typical MTM and operated with open tiebreaker) are re-evaluated to demonstrate that traditional low capital cost design may miss improvement opportunities. Those opportunities can be major capital expenditure reduction, power quality improvement, MV motor soft starter deletion, and improved system stability to name a few. Many designers may not have considered the component interrelationships and/or their tradeoffs when in an integrated system. The designer and/or user should consider the advantages of higher short-circuit capacity (SCC) systems by integrating fault current limiters and MV switchgear. Utilizing higher SCC systems permits power system designer optimization opportunities not possible before using conventional design methods. This paper will provide documentation of substantial savings of capital investment and energy under higher SCC conditions. The savings in one system component will offset another's increased cost. An obvious benefit of stiffer systems is ease of direct-on-line starting of large motor-driven compressor trains. The future need for motor soft starters minimizing system impact will be challenged. This paper may change fundamental system design methodology for system designers by removing several performance tradeoffs. This paper, in its original version, was previously presented at the 2010 IEEE/IAS/Petroleum Chemical Industry Conference. It was expanded with new sections for the 2017 IEEE/Industry Applications Society (IAS)/Pulp, Paper Forestry Industries Conference to include pre-emptive prefault adjustable power quality and multisourced networked power systems.
Autors: Raymond Catlett;Samy Faried;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2018, volume: 54, issue:1, pages: 923 - 933
Publisher: IEEE
 
» Optimization-Based Contact Fault Alleviation in Deep Brain Stimulation Leads
Abstract:
Deep brain stimulation (DBS) is a neurosurgical treatment in, e.g., Parkinson’s Disease. Electrical stimulation in DBS is delivered to a certain target through electrodes implanted into the brain. Recent developments aiming at better stimulation target coverage and lesser side effects have led to an increase in the number of contacts in a DBS lead as well as higher hardware complexity. This paper proposes an optimization-based approach to alleviation of the fault impact on the resulting therapeutical effect in field steering DBS. Faulty contacts could be an issue given recent trends of increasing number of contacts in DBS leads. Hence, a fault detection/alleviation scheme, such as the one proposed in this paper, is necessary ensure resilience in the chronic stimulation. Two alternatives are considered and compared with the stimulation prior to the fault: one using higher amplitudes on the remaining contacts and another with alleviating contacts in the neighborhood of the faulty one. Satisfactory compensation for a faulty contact can be achieved in both ways. However, to designate alleviating contacts, a model-based optimization procedure is necessary. Results suggest that stimulating with more contacts yields configurations that are more robust to contact faults, though with reduced selectivity.
Autors: Ruben Cubo;Mattias Åström;Alexander Medvedev;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Jan 2018, volume: 26, issue:1, pages: 69 - 76
Publisher: IEEE
 
» Optimized FPGA Implementation of Model Predictive Control for Embedded Systems Using High-Level Synthesis Tool
Abstract:
Model predictive control (MPC) is an optimization-based strategy for high-performance control that is attracting increasing interest. While MPC requires the online solution of an optimization problem, its ability to handle multivariable systems and constraints makes it a very powerful control strategy specially for MPC of embedded systems, which have an ever increasing amount of sensing and computation capabilities. We argue that the implementation of MPC on field programmable gate arrays (FPGAs) using automatic tools is nowadays possible, achieving cost-effective successful applications on fast or resource-constrained systems. The main burden for the implementation of MPC on FPGAs is the challenging design of the necessary algorithms. We outline an approach to achieve a software-supported optimized implementation of MPC on FPGAs using high-level synthesis tools and automatic code generation. The proposed strategy exploits the arithmetic operations necessaries to solve optimization problems to tailor an FPGA design, which allows a tradeoff between energy, memory requirements, cost, and achievable speed. We show the capabilities and the simplicity of use of the proposed methodology on two different examples and illustrate its advantages over a microcontroller implementation.
Autors: Sergio Lucia;Denis Navarro;Óscar Lucía;Pablo Zometa;Rolf Findeisen;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Jan 2018, volume: 14, issue:1, pages: 137 - 145
Publisher: IEEE
 
» Optimized Reconfigurable Fast Convolution-Based Transmultiplexers for Flexible Radio Access
Abstract:
Multirate fast-convolution (FC) processing can be used for realizing low-complexity filter banks (FBs) and transmultiplexers (TMUXs). The main advantage of the FC-based realizations when compared with the polyphase FBs is the increased configurability, that is, the number of subchannels, their bandwidths, and the center frequencies can be adjusted independently. In general, FC-based FBs are linear periodically shift-variant systems. In this brief, novel matrix representations for the FC synthesis and analysis FBs are first derived. These representations give all the shift-variant impulse responses of the FC-based FBs. Then the TMUX optimization criteria are expressed using these representations. Two examples are included to demonstrate the performance of the optimized designs as well as to illustrate the flexibility of the resulting FC-based TMUXs.
Autors: Juha Yli-Kaakinen;Markku Renfors;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2018, volume: 65, issue:1, pages: 130 - 134
Publisher: IEEE
 
» Optimizing FIPP- ${p}$ -Cycle Protection Design to Realize Availability-Aware Elastic Optical Networks
Abstract:
This letter tries to optimize the availability-aware service provisioning (AaSP) with failure-independent path-protecting pre-configured cycles (FIPP--cycles) in elastic optical networks (EONs). We propose a novel AaSP-FIPP scheme by leveraging bandwidth-squeezed restoration, develop a mathematical model to analyze the service availability of the scheme, and design a topology partitioning method to improve its scalability.
Autors: Xiaoliang Chen;Muqing Zhou;Shilin Zhu;Sheng Kang;Lu Sun;Zuqing Zhu;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 65 - 68
Publisher: IEEE
 
» Optimizing the Bit Transmission Power for Link Layer Energy Efficiency Under Imperfect CSI
Abstract:
In this paper, we study the issue of selecting the transmission power (energy per symbol) to minimize the expected energy required to successfully deliver a link-layer packet to the destination node in a wireless link performing the automatic repeat request. We consider the system that has a slow-fading channel and employs a minimum mean square error-based channel estimation scheme for a pilot symbol-assisted modulation. We derive a closed-form expression for the packet error probability (PkEP) in the presence of channel estimation error, and we use this expression for minimizing the PkEP in allocating the transmission energy among the pilot and data symbols. We also derive the expected energy required to successfully deliver a link-layer packet as a function of the transmission power and present an optimization method based on the properties of this function.
Autors: Ali Zarei Ghanavati;Daniel C. Lee;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 29 - 40
Publisher: IEEE
 
» Optimum Radio Resource Management in Carrier Aggregation Based LTE-Advanced Systems
Abstract:
Carrier aggregation (CA) functionality introduces new challenges for radio resource management (RRM) function of network. In this paper, an optimum and efficient RRM algorithm is proposed for Long Term Evolution-Advanced with reduced complexity and compared with the state-of-the-art (SOTA) solutions. The proposed algorithm optimally assigns component carriers, resource blocks, and modulation and coding scheme values to users, based on their channel state information and CA capabilities. Most of the SOTA solutions are based on approximate approaches that have much inferior performance compared to the performance of our proposed optimal solution. Furthermore, performance of the proposed solution has been evaluated using system-level simulations, and results show clearly that the proposed algorithm outperforms the SOTA algorithms in terms of fairness throughput and average cell throughput.
Autors: Soheil Rostami;Kamran Arshad;Predrag Rapajic;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2018, volume: 67, issue:1, pages: 580 - 589
Publisher: IEEE
 
» Optimum Transmitter Current Distribution for Dynamic Wireless Power Transfer With Segmented Array
Abstract:
The misalignment problem is a major challenge in dynamic wireless power transfer systems with a segmented transmitter (Tx) array. Tx coils farther away from receiver (Rx) experience higher currents as compared to Tx coils nearer to Rx coil leading to higher losses and lower performances. This paper reports theoretical optimum current distribution among Tx coils for any Rx position. A current amplitude modulation scheme is analyzed with the analogy of N-Cartesian coordinate equivalent of spherical coordinates. Efficiency and transferred power are evaluated for the proposed current distribution, and further optimization is performed with respect to load resistance, operating frequency, and the number of simultaneously powered Tx coils. The maximum performances that can be obtained with the optimized design conditions have been derived as well. The analysis is validated using numerical and experimental results.
Autors: Prasad Kumara Sampath Jayathurathnage;A. Alphones;D. Mahinda Vilathgamuwa;Andrew Ong;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2018, volume: 66, issue:1, pages: 346 - 356
Publisher: IEEE
 
» Orko: Facilitating Multimodal Interaction for Visual Exploration and Analysis of Networks
Abstract:
Data visualization systems have predominantly been developed for WIMP-based direct manipulation interfaces. Only recently have other forms of interaction begun to appear, such as natural language or touch-based interaction, though usually operating only independently. Prior evaluations of natural language interfaces for visualization have indicated potential value in combining direct manipulation and natural language as complementary interaction techniques. We hypothesize that truly multimodal interfaces for visualization, those providing users with freedom of expression via both natural language and touch-based direct manipulation input, may provide an effective and engaging user experience. Unfortunately, however, little work has been done in exploring such multimodal visualization interfaces. To address this gap, we have created an architecture and a prototype visualization system called Orko that facilitates both natural language and direct manipulation input. Specifically, Orko focuses on the domain of network visualization, one that has largely relied on WIMP-based interfaces and direct manipulation interaction, and has little or no prior research exploring natural language interaction. We report results from an initial evaluation study of Orko, and use our observations to discuss opportunities and challenges for future work in multimodal network visualization interfaces.
Autors: Arjun Srinivasan;John Stasko;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 511 - 521
Publisher: IEEE
 
» Orthogonal Fluxgate Gradiometer With Multiple Coil Pairs
Abstract:
In this paper, we study the possibility to exploit the noise correlation in a fundamental mode orthogonal fluxgate used as a gradiometer in order to maximize the noise suppression. We study the correlation of the noise along a single core fluxgate using two short coils at a variable distance, and we derive how it drops as the distance increases. Furthermore, we observed this phenomenon with the central point of the coils located at different parts of the wire, obtaining a similar behavior. This implies that the noise propagates in the core in a similar fashion, and—most important—that any mechanism taking advantage of the noise correlation to suppress noise can be replicated along the whole length of the core. We have also investigated the dependence of the noise correlation on the ac component of the excitation current, finding out that in the range where the 1/f noise of the magnetometer does not significantly change larger excitation current increases the correlation thus must be preferred as it allows better noise suppression when used as a gradiometer. Next, we verified that the noise suppression mechanism based on correlation does in fact return lower noise at higher correlation verifying that it matches with the expected values. Finally, we proposed a new configuration of the gradiometer where instead of two long coils we use multiple short coils at close distance calculating that the maximum length of such coils in order to take advantage of this configuration. We also explain that the response of such configuration of the gradiometer to the homogeneous field is zero even if the single coils are not symmetric with the respect of the center of the core if the pairs of coils are all symmetric.
Autors: M. Butta;M. Janosek;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2018, volume: 54, issue:1, pages: 1 - 5
Publisher: IEEE
 
» Outage Analysis of a SIMO FSO System Over an Arbitrarily Correlated $mathcal {M}$ -Distributed Channel
Abstract:
In this letter, we present the outage performance analysis of a single-input multiple-output free-space optical system with selection combining over an arbitrarily correlated Málaga -distributed channel. A novel and generalized analytical expression for the joint probability density function of the received signal-to-noise ratio, using Green’s matrix approximation, is derived in the form of power series. The proposed expression is valid for an arbitrary correlation model and can be mapped to most of the other existing distributions characterizing different atmospheric turbulence conditions. Moreover, mapping of correlated -distribution to correlated Gamma–Gamma and distributions is illustrated with the help of derived analytical results; correctness of the mapped distributions is verified by simulation.
Autors: Richa Priyadarshani;Manav R. Bhatnagar;Zabih Ghassemlooy;Stanislav Zvanovec;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:2, pages: 141 - 144
Publisher: IEEE
 
» Outage Probability Analysis of Non-Orthogonal Multiple Access in Cloud Radio Access Networks
Abstract:
To improve system capacity and spectral efficiency, as well as support more connections in cloud radio access networks (C-RANs), the application of non-orthogonal multiple access (NOMA), a promising technique in the physical layer, is considered in this letter. The stochastic geometry is used to obtain the outage probability of NOMA-based downlink C-RAN, in which the remote radio heads are uniformly distributed and serve two paired users simultaneously. A closed-form approximation for the outage probability is derived, and Monte Carlo simulations are provided to validate the accuracy of the theoretical analysis. Compared with conventional multiple access techniques, both the obtained analytical and simulation results demonstrate that the proposed NOMA scheme can offer better spectral efficiency and user fairness in C-RANs.
Autors: Xiang Gu;Xiaodong Ji;Zhiguo Ding;Wenbin Wu;Mugen Peng;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 149 - 152
Publisher: IEEE
 
» p-i-p-i-n Separate Absorption and Multiplication Ultraviolet Avalanche Photodiodes
Abstract:
Front-illuminated GaN-based separate absorption and multiplication (SAM) ultraviolet (UV) avalanche photodiodes (APDs) with various photon detection areas are demonstrated grown by metalorganic chemical vapor deposition on bulk GaN native substrates with low dislocation density. By adopting a front-illuminated UV-APD structure with a thin AlGaN window layer, no additional etching of the substrate for the reduction of strong UV absorption is required. The epitaxial layer structure of the p-i-p-i-n SAM UV-APDs consists of a Mg-doped -Al0.05Ga0.95N window layer to minimize UV absorption at the top surface region and a Mg-graded -GaN charge layer to serve as a field-termination layer. The onset point of the breakdown voltage () is around 73 V for all SAM-APDs with different mesa areas ranging from 1963 to 10, which is a lower than the typical p-i-n UV-APDs with the similar thickness of undoped layer, where the photon absorption and multiplication processes take place simultaneously. Under UV-light illumination at nm, the SAM-APDs exhibit high avalanche gains greater than at a reverse bias of V
Autors: Mi-Hee Ji;Jeomoh Kim;Theeradetch Detchprohm;Yuanzheng Zhu;Shyh-Chiang Shen;Russell D. Dupuis;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:2, pages: 181 - 184
Publisher: IEEE
 

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