Electrical and Electronics Engineering publications abstract of: 02-2018 sorted by title, page: 13

» One-Dimensional Mirrored Aperture Synthesis With Rotating Reflector
Abstract:
In this letter, 1-D mirrored aperture synthesis with a rotating reflector (1-D MAS-R) is proposed to improve the spatial resolution and reduce the number of required antennas for passive microwave remote sensing. The principle of the 1-D MAS-R with an antenna array is given, and from the principle, the 1-D MAS-R with only one antenna can also reconstruct the image of the scene. Simulation results demonstrate the validity of the 1-D MAS-R even with only one antenna, and the spatial resolution is improved by increasing the distance between the reflector and the antenna or antenna array.
Autors: Haofeng Dou;Qingxia Li;Liangqi Gui;Ke Chen;Yufang Li;Congcong Huang;Menglin Hu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Feb 2018, volume: 15, issue:2, pages: 197 - 201
Publisher: IEEE
 
» Online Active Learning in Data Stream Regression Using Uncertainty Sampling Based on Evolving Generalized Fuzzy Models
Abstract:
In this paper, we propose three criteria for efficient sample selection in case of data stream regression problems within an online active learning context. The selection becomes important whenever the target values, which guide the update of the regressors as well as the implicit model structures, are costly or time-consuming to measure and also in case when very fast models updates are required to cope with stream mining real-time demands. Reducing the selected samples as much as possible while keeping the predictive accuracy of the models on a high level is, thus, a central challenge. This should be ideally achieved in unsupervised and single-pass manner. Our selection criteria rely on three aspects: 1) the extrapolation degree combined with the model's nonlinearity degree , which is measured in terms of a new specific homogeneity criterion among adjacent local approximators; 2) the uncertainty in model outputs, which can be measured in terms of confidence intervals using so-called adaptive local error bars — we integrate a weighted localization of an incremental noise level estimator and propose formulas for online merging of local error bars; 3) the uncertainty in model parameters, which is estimated by the so-called A-optimality criterion, which relies on the Fisher information matrix. The selection criteria are developed in combination with evolving generalized Takagi–Sugeno (TS) fuzzy models (containing rules in arbitrarily rotated position), as it could be shown in previous publications that these outperform conventional evolving TS models (containing axis-parallel rules). The results based on three high-dimensional real-world streaming problems show that a model update based on only 10%–20% selected samples can still achieve similar ac- umulated model errors over time to the case when performing a full model update on all samples. This can be achieved with a negligible sensitivity on the size of the active learning latency buffer. Random sampling with the same percentages of samples selected, however, achieved much higher error rates. Hence, the intelligence in our sample selection concept leads to an economic balance between model accuracy and measurement as well computational costs for model updates.
Autors: Edwin Lughofer;Mahardhika Pratama;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2018, volume: 26, issue:1, pages: 292 - 309
Publisher: IEEE
 
» Online Built-In Self-Test of High Switching Frequency DC–DC Converters Using Model Reference Based System Identification Techniques
Abstract:
A built-in self-test (BIST) technique that enables tracking of loop parameters of integrated DC–DC converters without affecting the normal mode of operation is presented. A digital pseudo-noise based stimulus and a mixed signal cross-correlation based analysis technique is used to derive on-chip impulse response, with minimum computational requirements in comparison to a digital correlator approach. Using measured impulse response, open-loop phase margin and closed-loop unity-gain frequency are estimated within 5.2% and 4.1% error, respectively, for the load current range of 30 mA to 200 mA. Converter parameters, such as natural frequency, -factor, and center frequency are estimated within 3.6%, 4.7%, and 3.8% error, respectively, over load inductance of 4.7 to 10.3 , and filter capacitance of 200 nF to 400 nF. A 5 MHz switching frequency, 5 V to 8.125 V input voltage range, voltage-mode controlled DC-DC buck converter is designed for the proposed model reference based parametric and non-parametric BIST analysis. The converter output voltage range is 3.3 V to 5 V and supported maximum load current is 450 mA with a peak efficiency of 87.93%. The proposed converter is fabricated on a 0.6 6 layer-metal SOI technology with a die area of 9 mm2. The system identification circuitry occupies 3.8% of the converter area with 530 quiescent current during operation.
Autors: Navankur Beohar;Venkata N. K. Malladi;Debashis Mandal;Sule Ozev;Bertan Bakkaloglu;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2018, volume: 65, issue:2, pages: 818 - 831
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: Feb 2018, volume: 54, issue:1, pages: 712 - 721
Publisher: IEEE
 
» Online Soft-Error Vulnerability Estimation for Memory Arrays and Logic Cores
Abstract:
Radiation-induced soft errors are a major reliability concern in circuits fabricated at advanced technology nodes. Online soft-error vulnerability estimation offers the flexibility of exploiting dynamic fault-tolerant mechanisms for cost-effective reliability enhancement. We propose a generic run-time method with low area and power overhead to predict the soft-error vulnerability of on-chip memory arrays as well as logic cores. The vulnerability prediction is based on signal probabilities (SPs) of a small set of flip-flops, chosen at design time, by studying the correlation between the soft-error vulnerability and the flip-flop SPs for representative workloads. We exploit machine learning to develop a predictive model that can be deployed in the system in software form. Simulation results on two processor designs show that the proposed technique can accurately estimate the soft-error vulnerability of on-chip logic core, such as sequential pipeline logic and functional units as well as memory arrays that constitute the instruction cache, the data cache, and the register file.
Autors: Arunkumar Vijayan;Saman Kiamehr;Mojtaba Ebrahimi;Krishnendu Chakrabarty;Mehdi B. Tahoori;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Feb 2018, volume: 37, issue:2, pages: 499 - 511
Publisher: IEEE
 
» Operating DC Circuit Breakers With MMC
Abstract:
High voltage direct current (HVDC) grids may be protected from dc faults through the application of HVDC circuit breakers. Recent advances in dc circuit breaker technologies may allow faults in the dc grid to be cleared without a permanent loss of power to the connected ac grids. The requirements for the protection have yet to be fully defined; especially where half-bridge modular multilevel converter (MMC) controls are concerned. This paper investigates integrating dc circuit breakers with half-bridge MMC converters, specifically looking to at how to recover from a pole-to-pole fault. The fault response of the converter to a fault is analyzed in depth. This analysis highlights key stages in the converter response to a dc fault, allowing the MMC fault currents to be predicted. This analysis is then verified in PSCAD simulations and the power flow recovery is shown. The converter controls are investigated, improvements made to the power flow recovery, and the need for arm current controllers highlighted.
Autors: Oliver Cwikowski;Alan Wood;Allan Miller;Mike Barnes;Roger Shuttleworth;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 260 - 270
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: Feb 2018, volume: 54, issue:1, pages: 916 - 922
Publisher: IEEE
 
» Operation Modes and Combination Control for Urban Multivoltage-Level DC Grid
Abstract:
With the development of urban economy and the growing integration of renewable energy, there are increasing challenges on the urban power grid. Due to the transmission stress and short-circuit current limitation, the traditional urban power grid cannot satisfy the new requirements. Multivoltage-level dc grid (MDCG) is an alternative approach to the urban power grid upgrade. This paper presents an MDCG topology, which can be used in a future urban power grid. Three operation modes of an urban MDCG are proposed: auto operation mode, power-limited operation mode, and stand-alone operation mode. The auto operation mode is the normal one for urban MDCG. The power-limited operation mode is designed to keep the capability to support urban high voltage ac transmission grid in emergencies. The stand-alone operation mode is used to keep stability in case the dc–dc converter system outage occurs. The combination control of three operation modes is put forward to enhance the reliability of urban MDCG in various operating conditions. The simulation results show that the proposed operation modes and combination control are effective and have good performance.
Autors: Kaiqi Sun;Ke-Jun Li;Zhuo-di Wang;Huadong Sun;Mingqiang Wang;Zhijie Liu;Meiyan Wang;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 360 - 370
Publisher: IEEE
 
» Operation of a Hollow Cathode Neutralizer for Sub-100-W Hall and Ion Thrusters
Abstract:
We explore the operation of the Rafael heaterless hollow cathode (RHHC) at low discharge current levels corresponding to sub-100-W Hall and ion thrusters operation. We present experimental results of the cathode operating at discharge current levels of 0.2–0.5 A and mass flow rates of 0.2 and 0.25 mg/s. For each operational condition, potential measurements near the cathode region, in the cathode plume, and on the anode were conducted. We show that the cathode may operate in a self-sustained mode at discharge current levels down to 0.35 A. We show that the cathode coupling potential increases as the discharge current is decreased and may reach values of 40 V at the lowest discharge current. Accordingly, the cathode coupling power is estimated to account for up to 14 W of the anode power supply power. We show that when the RHHC cathode is coupled with a hypothetical very low-power Hall thruster, the estimated cathode power intake would be 10%–23% of the overall thruster power. Finally, using external cathode body temperature measurements, we assess the radiated power from the cathode surface to be lower than 1 W. Overall, we demonstrate that the RHHC cathode is suitable for operation with very low-power Hall and ion thrusters for discharge power under 100 W.
Autors: Dan R. Lev;Gal Alon;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Feb 2018, volume: 46, issue:2, pages: 311 - 318
Publisher: IEEE
 
» Operational Interpretation of Rényi Information Measures via Composite Hypothesis Testing Against Product and Markov Distributions
Abstract:
We revisit the problem of asymmetric binary hypothesis testing against a composite alternative hypothesis. We introduce a general framework to treat such problems when the alternative hypothesis adheres to certain axioms. In this case, we find the threshold rate, the optimal error and strong converse exponents (at large deviations from the threshold), and the second order asymptotics (at small deviations from the threshold). We apply our results to find the operational interpretations of various Rényi information measures. In case the alternative hypothesis is comprised of bipartite product distributions, we find that the optimal error and strong converse exponents are determined by the variations of Rényi mutual information. In case the alternative hypothesis consists of tripartite distributions satisfying the Markov property, we find that the optimal exponents are determined by the variations of Rényi conditional mutual information. In either case, the relevant notion of Rényi mutual information depends on the precise choice of the alternative hypothesis. As such, this paper also strengthens the view that different definitions of Rényi mutual information, conditional entropy, and conditional mutual information are adequate depending on the context in which the measures are used.
Autors: Marco Tomamichel;Masahito Hayashi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2018, volume: 64, issue:2, pages: 1064 - 1082
Publisher: IEEE
 
» Optical and Mechanical Excitation Thermography for Impact Response in Basalt-Carbon Hybrid Fiber-Reinforced Composite Laminates
Abstract:
In this paper, optical and mechanical excitation thermography was used to investigate basalt-fiber-reinforced polymer, carbon-fiber-reinforced polymer, and basalt-carbon fiber hybrid specimens subjected to impact loading. Interestingly, two different hybrid structures including sandwich-like and intercalated stacking sequence were used. Pulsed phase thermography, principal component thermography, and partial least-squares thermography (PLST) were used to process the thermographic data. X-ray computed tomography was used for validation. In addition, signal-to-noise ratio analysis was used as a means of quantitatively comparing the thermographic results. Of particular interest, the depth information linked to Loadings in PLST was estimated for the first time. Finally, a reference was provided for taking advantage of different hybrids in view of special industrial applications.
Autors: Hai Zhang;Stefano Sfarra;Fabrizio Sarasini;Clemente Ibarra-Castanedo;Stefano Perilli;Henrique Fernandes;Yuxia Duan;Jeroen Peeters;Nicolas P. Avdelidis;Xavier Maldague;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2018, volume: 14, issue:2, pages: 514 - 522
Publisher: IEEE
 
» Optical Feedback Flowmetry: Impact of Particle Concentration on the Signal Processing Method
Abstract:
Optical feedback interferometry (OFI)-based flow-metry enables simple, robust, self-aligned, and low-cost systems to measure the fluid flow velocity with reasonable accuracy. The particle concentration in the fluid causes significant changes in the signal of OFI sensors. While the spectral analysis of the particle induced Doppler shift remains as the most usual approach to determine the flow properties, different processing algorithms have been proposed in order to evaluate the average flow velocity within the measurement volume. In this paper, the validity of the commonly used methods with regards to particle concentrations and flow rates is verified.
Autors: Reza Atashkhooei;Evelio E. Ramírez-Miquet;Raul da Costa Moreira;Adam Quotb;Santiago Royo;Julien Perchoux;
Appeared in: IEEE Sensors Journal
Publication date: Feb 2018, volume: 18, issue:4, pages: 1457 - 1463
Publisher: IEEE
 
» Optical Magnetic Field Sensor Based on Electrogyratory and Electrooptic Compensation in Single Quartz Crystal
Abstract:
An optical magnetic field sensor based on electrogyratory and electrooptic compensation is proposed and experimentally demonstrated. Besides natural birefringence and optical activity, single quartz crystal simultaneously exhibits the magnetooptical Faraday effect, electrooptic Pockels effect, electrogyratory effect, and so on. For the intensity-modulated light sensing signal, the Faraday rotation angle can be compensated by both electrogyratory angle and electrooptic phase retardation. The 50-Hz ac magnetic flux density has been measured within 267 Gs by using a block of single quartz crystal, and typical compensating voltage is about ~ Gs−1. Advantages of the proposed magnetic field sensor mainly include closed-loop optical measurement of magnetic field or current, low compensating voltage, moderate temperature dependence of electrooptic and electrogyratory effects, a solid sensing unit, and low cost.
Autors: Changsheng Li;He Cui;Xuan Zhang;
Appeared in: IEEE Sensors Journal
Publication date: Feb 2018, volume: 18, issue:4, pages: 1427 - 1434
Publisher: IEEE
 
» Optical Mapping of RF Field Profiles in Resonant Microwave Circuits
Abstract:
We demonstrate a technique for mapping the electric field profiles in resonant microwave circuits. Optical pumping of microwave circuits fabricated on semiconductor substrates is shown to result in a modulation of the load power dependent on the local electric field of the microwave signal in the resonant circuit. By reading out the modulation in transmitted signal as a function of the position of the optical excitation, for a range of driving frequencies, we are able to produce 2D images related to the microwave electric fields in our circuits. Images are generated for a range of resonator designs and compared to numerical simulations. The presented technique is analytically modeled for insight to the relationship between electric field and modulation signal.
Autors: Sukrith Dev;Runyu Liu;Jeffery W. Allen;Monica S. Allen;Brett R. Wenner;Daniel Wasserman;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2018, volume: 30, issue:4, pages: 331 - 334
Publisher: IEEE
 
» Optical Properties of Eu3+-Doped Y2O3 Nanotubes and Nanosheets Synthesized by Hydrothermal Method
Abstract:
Y2O3:Eu3+ nanomaterials were obtained using a low-cost, large-scale, solution-based hydrothermal method followed by a thermal annealing process. The morphology of the Y2O3 :Eu3+ nanomaterials can be controlled by tuning the aging time, aging temperature, and the pH values of the suspension. The optical properties of Y2O3:Eu3+ nanosheets and nanotubes were investigated with the goal of improving the material's functionalities. Synchrotron X-ray diffraction patterns, field emission scanning electron microscopy images, high-resolution transmission electron microscopy images, emission spectra, excitation spectra, and fluorescence decay curves were measured and compared. The results showed that a novel Eu3+ environment exists in Y2O3:Eu3+ nanosheets, which led to rapid decay of emission at 611 nm. The unique properties of Y2O3:Eu 3+ nanosheets could lead to potential applications in white light-emitting diodes (LEDs) based on GaAlN deep UV LEDs.
Autors: Peifen Zhu;William Wang;Hongyang Zhu;Preston Vargas;August Bont;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 10
Publisher: IEEE
 
» Optically Pumped Hybrid Plasmonic-Photonic Waveguide Modulator Using the VO2 Metal-Insulator Phase Transition
Abstract:
The need for ever faster and more efficient computation and communication devices has spurred interest in the field of all-optical modulators. Here a small-size hybrid plasmonic-photonic all-optical waveguide modulator utilizing a subwavelength Au/VO2 nanostructure is proposed as a high-modulation optically actuatable modulator. Using finite-difference-time-domain simulations, a nanoscale (320 nm × 300 nm cross-section) optimized modulator is designed. The modulator design has an extinction ratio as high as 26.85 dB/μm, and a length of only 550 nm.
Autors: J. Kenji Clark;Ya-Lun Ho;Hiroaki Matsui;Jean-Jacques Delaunay;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 9
Publisher: IEEE
 
» Optimal and Suboptimal Velocity Estimators for ArcSAR With Distributed Target
Abstract:
Two new methods of radial velocity estimation for distributed targets in arc-scanning synthetic aperture radar (ArcSAR) systems, namely, the maximum-likelihood estimator (MLE) and the suboptimal method based on the least squares estimation (LSE), are proposed, derived, and analyzed. To this end, we establish that scatterers of the distributed target are uniformly dispersed within the radar resolution cell of dimensions and they move randomly at different velocities. Furthermore, the effect of the antenna pattern is considered to characterize the amplitude of the scattered signal. Thus, from the coherent integration of the scatters at each pulse repetition interval in radar scanning, data sequences are obtained as samples of the composite signal, which follows a multivariate normal distribution. From this, the covariance matrix, upon which the methods are based, is derived. Simulations have been carried out to compare the new methods with existing methods, namely, phase, energy, and correlation, as a function of the signal-to-noise ratio. Finally, the results show that the MLE and LSE methods outperform the conventional methods, providing a gain of more than 10 dB.
Autors: Andrea Carolina Flores Rodriguez;Gustavo Fraidenraich;Tarcísio A. P. Soares;José Cândido S. Santos Filho;Marco A. M. Miranda;Michel Daoud Yacoub;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Feb 2018, volume: 15, issue:2, pages: 252 - 256
Publisher: IEEE
 
» Optimal Decision Making for Big Data Processing at Edge-Cloud Environment: An SDN Perspective
Abstract:
With the evolution of Internet and extensive usage of smart devices for computing and storage, cloud computing has become popular. It provides seamless services such as e-commerce, e-health, e-banking, etc., to the end users. These services are hosted on massive geodistributed data centers (DCs), which may be managed by different service providers. For faster response time, such a data explosion creates the need to expand DCs. So, to ease the load on DCs, some of the applications may be executed on the edge devices near to the proximity of the end users. However, such a multiedge-cloud environment involves huge data migrations across the underlying network infrastructure, which may generate long migration delay and cost. Hence, in this paper, an efficient workload slicing scheme is proposed for handling data-intensive applications in multiedge-cloud environment using software-defined networks (SDN). To handle the inter-DC migrations efficiently, an SDN-based control scheme is presented, which provides energy-aware network traffic flow scheduling. Finally, a multileader multifollower Stackelberg game is proposed to provide cost-effective inter-DC migrations. The efficacy of the proposed scheme is evaluated on Google workload traces using various parameters. The results obtained show the effectiveness of the proposed scheme.
Autors: Gagangeet Singh Aujla;Neeraj Kumar;Albert Y. Zomaya;Rajiv Ranjan;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2018, volume: 14, issue:2, pages: 778 - 789
Publisher: IEEE
 
» Optimal Guaranteed Cost Sliding-Mode Control of Interval Type-2 Fuzzy Time-Delay Systems
Abstract:
This paper is concerned with the optimal guaranteed cost sliding-mode control problem for interval type-2 (IT2) Takagi–Sugeno fuzzy systems with time-varying delays and exogenous disturbances. In the presence of the uncertain parameters hidden in membership functions, an adaptive method is presented to handle the time-varying weight coefficients reflecting the change of the uncertain parameters. A new integral sliding surface is presented based on the system output. By designing a novel adaptive sliding-mode controller, system perturbation or modeling error can be compensated, and the reachability of the sliding surface can be guaranteed with the ultimate uniform boundedness of the closed-loop system. Optimal conditions of an guaranteed cost function and an performance index are established for the resulting time-delay control system. Finally, an inverted pendulum system represented by the IT2 fuzzy model is applied to illustrate the advantages and effectiveness of the proposed control scheme.
Autors: Hongyi Li;Jiahui Wang;Ligang Wu;Hak-Keung Lam;Yabin Gao;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2018, volume: 26, issue:1, pages: 246 - 257
Publisher: IEEE
 
» Optimal Objective-Based Experimental Design for Uncertain Dynamical Gene Networks with Experimental Error
Abstract:
In systems biology, network models are often used to study interactions among cellular components, a salient aim being to develop drugs and therapeutic mechanisms to change the dynamical behavior of the network to avoid undesirable phenotypes. Owing to limited knowledge, model uncertainty is commonplace and network dynamics can be updated in different ways, thereby giving multiple dynamic trajectories, that is, dynamics uncertainty. In this manuscript, we propose an experimental design method that can effectively reduce the dynamics uncertainty and improve performance in an interaction-based network. Both dynamics uncertainty and experimental error are quantified with respect to the modeling objective, herein, therapeutic intervention. The aim of experimental design is to select among a set of candidate experiments the experiment whose outcome, when applied to the network model, maximally reduces the dynamics uncertainty pertinent to the intervention objective.
Autors: Daniel N. Mohsenizadeh;Roozbeh Dehghannasiri;Edward R. Dougherty;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Feb 2018, volume: 15, issue:1, pages: 218 - 230
Publisher: IEEE
 
» Optimal Offering of Demand Response Aggregation Company in Price-Based Energy and Reserve Market Participation
Abstract:
This paper investigates the combined price-based scheduling/participation of generation company (GENCO) and demand response aggregation company (DRACO) in energy and reserve markets. The temporally coupled customer behavior can be better represented using the load profile attributes, when compared to the traditional approach with random willingness assignment. The proposed cost models for energy and reserve offerings consider the effect of load type, load pattern consumption, and availability/flexibility patterns of each type of load with time of use constraints. The load curtailment (LC) cost model accounts for criticality and willingness of the responsive loads via utilization factor and availability factors, respectively. The proposed cost models present a realistic picture of LC cost by eliminating the random willingness factor of the existing LC cost models. Thereafter, various cases of market participation with different reserve payment policies are formulated for combined participation of GENCO and DRACO. In addition, the sensitivity of participation decision of various entities to the seasonal load variation is examined for summer and winter loading profiles. The proposed cost models and scheduling framework is simulated using GENCO with ten thermal units and DRACO with various load types, profiles distributed across different load sectors comprising of commercial, residential, industrial, municipal, and agricultural loads. The combined participation resulted in improved market surplus with reduced GENCO surplus. Also, the energy and reserve market surplus dependence on seasonal load patterns is observed across different test cases and payment policies.
Autors: Srikanth Reddy Konda;Lokesh Kumar Panwar;Bijaya Ketan Panigrahi;Rajesh Kumar;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2018, volume: 14, issue:2, pages: 578 - 587
Publisher: IEEE
 
» Optimal Placement of GIC Blocking Devices Considering Equipment Thermal Limits and Power System Operation Constraints
Abstract:
A practical mitigation of the geomagnetic disturbance (GMD) consequences in power systems is not possible without taking into account the equipment thermal limits and operational constraints. This paper presents such limitations, develops the required equations and characteristics, and proposes a general and comprehensive approach to incorporate these limits in any short-term or long-term geomagnetically induced current (GIC) mitigating solution. As an application, this study formulates the limits in the context of an optimal placement of the GIC blocking devices at the neutral point of the power transformers in the IEEE 118-bus benchmark study system. The proposed optimization problem takes into account synchronous generator real/reactive power capability, acceptable bus voltage magnitudes, transformer hot-spot heating, transmission-line thermal limits, capacitor bank harmonic loading, and synchronous generator rotor heating. This paper shows that the existing standards significantly underestimate the generator rotor heating under the GMD conditions and propose more accurate alternatives. The study results show that considering the equipment thermal limits results in a noticeably different solution when compared with the case of ignoring such limits.
Autors: Afshin Rezaei-Zare;Amir H. Etemadi;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 200 - 208
Publisher: IEEE
 
» Optimal Scheduling, Coordination, and the Value of RFID Technology in Garment Manufacturing Supply Chains
Abstract:
Motivated by industrial practices, we explore in this paper the optimal supply chain scheduling problem in garment manufacturing with the consideration of coordination and radio frequency identification (RFID) technology. We consider the case in which a garment manufacturer receives orders from multiple retailers, and needs to determine the optimal order set to take and the corresponding optimal production schedule. We model the problem as a flowshop scheduling problem, uncover its structural properties, and prove that the problem is NP-hard in the ordinary sense only. We contribute by first developing a practical and effective pseudopolynomial dynamic programming algorithm to find the globally optimal solution in reasonable time; second, proposing an implementable method to achieve win–win supply chain coordination; and third, showing the good performance of RFID technology deployment. We further determine the critical threshold value of the order number with which the total manufacturing capacity must be increased if companies in the supply chain wish to improve their profits.
Autors: Tsan-Ming Choi;Wing-Kwan Yeung;T. C. Edwin Cheng;Xiaohang Yue;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Feb 2018, volume: 65, issue:1, pages: 72 - 84
Publisher: IEEE
 
» Optimization and Analysis of Probabilistic Caching in $N$ -Tier Heterogeneous Networks
Abstract:
In this paper, we study the probabilistic caching for an -tier wireless heterogeneous network (HetNet) using stochastic geometry. A general and tractable expression of the successful delivery probability (SDP) is first derived. We then optimize the caching probabilities for maximizing the SDP in the high signal-to-noise ratio regime. The problem is proved to be convex and solved efficiently. We next establish an interesting connection between -tier HetNets and single-tier networks. Unlike the single-tier network where the optimal performance only depends on the cache size, the optimal performance of -tier HetNets depends also on the base station (BS) densities. The performance upper bound is, however, determined by an equivalent single-tier network. We further show that with uniform caching probabilities regardless of content popularities, to achieve a target SDP, the BS density of a tier can be reduced by increasing the cache size of the tier when the cache size is larger than a threshold; otherwise, the BS density and BS cache size can be increased simultaneously. It is also found analytically that the BS density of a tier is inverse to the BS cache size of the same tier and is linear to BS cache sizes of other tiers.
Autors: Kuikui Li;Chenchen Yang;Zhiyong Chen;Meixia Tao;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 1283 - 1297
Publisher: IEEE
 
» Optimization of Au-Free Ohmic Contact Based on the Gate-First Double-Metal AlGaN/GaN MIS-HEMTs and SBDs Process
Abstract:
The compatibility of Au-free (Ti/Al/Ti/TiN) ohmic contacts in the gate-first double-metal (GFDM) process for AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) and Schottky barrier diodes (SBDs) on the same 150-mm wafer was investigated and discussed for the first time, including contact pretreatments, Al diffusion in dielectric layers, and vias (contact windows between two metal layers) etching conditions. All of these steps are crucial to ohmic contacts as well as overall AlGaN/GaN device fabrication process. With the optimized ohmic contacts steps, not only an extremely low ohmic contact resistance () value of but also an excellent uniformity on the 150-mm wafer was obtained. The performance and uniformity of the MIS-HEMTs and SBDs based on the optimized GFDM process were also discussed.
Autors: Hui Sun;Meihua Liu;Peng Liu;Xinnan Lin;Jianguo Chen;Maojun Wang;Dongmin Chen;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 622 - 628
Publisher: IEEE
 
» Optimization of Fingerprints Reporting Strategy for WLAN Indoor Localization
Abstract:
This paper investigates how to optimize the fingerprints reporting strategy to improve localization accuracy, and how the optimal strategy theory can be utilized to streamline the design of WLAN fingerprinting localization systems. In particular, we first reveal that the fingerprints reporting problem is essentially an NP-Hard size-constrained supermodular maximization problem, and then show the inapplicability of the state-of-the-art approximation algorithms to the problem. We then propose a new algorithm and show that if the number of fingerprints measurements is large enough, then the localization accuracy is at most times worse than the optimal value, with any given constant close to 0. Moreover, we demonstrate how the optimal strategy theory can be utilized to improve accuracy of location estimation by resolving the issue of similar fingerprints for both faraway and close-by locations, with an iterative algorithm developed to cross check fingerprints sampled in different locations, in order to derive the best possible result of localization. Further, we reveal the relationship between accuracy of location estimation and coverage of Wi-Fi signals in indoor spaces when planning deployment of APs. Experiment results are presented to validate our theoretical analysis.
Autors: Xiaohua Tian;Wenxin Li;Yucheng Yang;Zhehui Zhang;Xinbing Wang;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Feb 2018, volume: 17, issue:2, pages: 390 - 403
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: Feb 2018, volume: 54, issue:1, pages: 923 - 933
Publisher: IEEE
 
» Optimization of SiC UMOSFET Structure for Improvement of Breakdown Voltage and ON-Resistance
Abstract:
This paper proposes an optimized structure of 4H-SiC U-shaped accumulation-mode MOSFET (U-ACCUFET), which exhibits lower on-resistance and higher breakdown voltage. In this structure, an n-doped region is added underneath the gate trench, which covers the p+ shielding region. The new appended section spreads out the electrons to the bottom of the p+ shielding region and conducts the electrons in the downward direction. Output on-state characteristic curves (–), on-resistance, transfer characteristic curves (–), threshold voltage (), subthreshold slope, and off-state characteristics of the optimized structure are observed. The proposed device shows on-resistance of 1.55 cm2 at V and V and breakdown voltage of 2624 V at V. The simulation results indicate a superior performance of the optimized U-ACCUFET structure as the on-resistance reduces by 6% and breakdown voltage increases by 7.2% as compared with that of the conventional one. Also, the figure of merit ${V}_{textsf {BR}}^{textsf {2}}/{R}_{ mathrm{scriptscriptstyle ON}}$ is improved by 21.6%.
Autors: Deepshikha Bharti;Aminul Islam;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 615 - 621
Publisher: IEEE
 
» Optimization of Sparse Frequency Diverse Array With Time-Invariant Spatial-Focusing Beampattern
Abstract:
The optimization of the sparse time-modulated optimized frequency offset frequency diverse array (S-TMOFO-FDA) with time-invariant spatial-focusing beampattern is presented. The minimum array with smallest number of elements is obtained through iterative optimization. From numerical results, the S-TMOFO-FDA can provide above 70% reduction in the element amount while displaying superior sidelobe performance than the same aperture-sized full uniform time-modulated logarithmically increasing frequency offset frequency diverse arrays. Furthermore, the scanning performance of the optimized array is also investigated. The S-TMOFO-FDAs of different array length are optimized.
Autors: Yu-Qian Yang;Hao Wang;Hai-Qing Wang;Si-Qi Gu;Da-Long Xu;Shuang-Long Quan;
Appeared in: IEEE Antennas and Wireless Propagation Letters
Publication date: Feb 2018, volume: 17, issue:2, pages: 351 - 354
Publisher: IEEE
 
» Optimization of Superlattice Barrier HgCdTe nBn Infrared Photodetectors Based on an NEGF Approach
Abstract:
Unipolar nBn photodetector structures have recently emerged as a viable alternative to the traditional p-n junction infrared photodiode approach. However, realization of a unipolar nBn detector technology using the mercury–cadmium–telluride (HgCdTe) alloy system is a challenging task because of the lack of a barrier material with a favorable valence band offset. In this paper, advanced quantum mechanical calculations, based on the nonequilibrium Green’s function (NEGF) formalism, are used to demonstrate that it is possible to achieve diffusion-limited dark current performance in HgCdTe nBn detectors by incorporating a type-III HgTe/CdTe superlattice (SL) barrier layer. Optimal design parameters for CdTe layer thickness, HgTe layer thickness, and total number of periods are presented in order to achieve maximum hole current transmission through the barrier layer, and therefore diffusion-limited dark current performance. The NEGF simulation framework herein presented allows greater insight into effects associated with electron and hole wave function propagation in the SL barrier layer as well as the calculation of individual carrier current components. The presented results form a good basis for the fabrication of high-performance SL barrier HgCdTe nBn detectors.
Autors: Nima Dehdashti Akhavan;Gilberto A. Umana-Membreno;Renjie Gu;Jarek Antoszewski;Lorenzo Faraone;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 591 - 598
Publisher: IEEE
 
» Optimization of Temperature, Targets, and Illumination for High Precision Photogrammetric Measurements
Abstract:
The cameras of a close-range photogrammetry system must be calibrated to find their positions and optical properties. This is a crucial step in ensuring the performance of the complete system, especially if micrometric precision over a large field of view and long-term reproducibility is required. The target positions within the images for camera calibration and measurements are perturbed if stability between images is not achieved. This paper aims to evaluate the optimal conditions to guarantee the stability of the target images during measurements and calibration. The effect of temperature on the target positions is estimated to be about 0.1 pixels during a camera warm-up period of 20 min or more. This effect is reduced to about 0.02 pixels after a warm-up period of less than 10 min by developing a controller for the camera’s pixel clock. Additionally, an approximately 22% variation of illumination intensity is found to cause a small, but clearly measurable effect between images. Other aspects studied here are the illumination angle and the target characteristics. A 180° movement of the illumination source with respect to the camera produces a 0.3 pixel change in the target locations when masked retroreflective targets are involved. In contrast, this effect is diminished by a factor of about ten with the use of larger, opaque targets.
Autors: Louise Dauvin;Holger Drass;Leonardo Vanzi;Rolando Dünner;Miguel Torres;Clémentine Béchet;David Boettger;Felipe Rojas;Tzu-Chiang Shen;
Appeared in: IEEE Sensors Journal
Publication date: Feb 2018, volume: 18, issue:4, pages: 1449 - 1456
Publisher: IEEE
 
» Optimized Active Disturbance Rejection Control for DC-DC Buck Converters With Uncertainties Using a Reduced-Order GPI Observer
Abstract:
The output voltage regulation problem of a PWM-based dc-dc buck converter under various sources of uncertainties and disturbances is investigated in this paper via an optimized active disturbance rejection control (ADRC) approach. Aiming to practical implementation, a new reduced-order generalized proportional integral (GPI) observer is first designed to estimate the lumped (possibly time-varying) disturbances within the dc-dc circuit. By integrating the disturbance estimation information raised by the reduced-order GPI observer into the output prediction, an optimized ADRC method is developed to achieve optimized tracking performance even in the presence of disturbances and uncertainties. It is shown that the proposed controller will guarantee the rigorous stability of the closed-loop system, for any bounded uncertainties of the circuit, by appropriately choosing the observer gains and the bandwidth factor. Experimental results illustrate that the proposed control solution is characterized by improved robustness performance against various disturbances and uncertainties compared with traditional ADRC and integral model predictive control (MPC) approaches.
Autors: Jun Yang;Hongyu Cui;Shihua Li;Argyrios Zolotas;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2018, volume: 65, issue:2, pages: 832 - 841
Publisher: IEEE
 
» Optimizing Cluster Size Through Handoff Analysis in User-Centric Cooperative Wireless Networks
Abstract:
User-centric base station (BS) cooperation has been regarded as an effective solution for improving network coverage and throughput in next-generation wireless systems. However, it also introduces more complicated handoff patterns, which may potentially degrade user performance. In this paper, we aim to theoretically quantify the tradeoff between handoff cost and data rate. Two user-centric clustering modes are investigated: number-based cooperation (NBC), which is easier to implement, and distance-based cooperation (DBC), which gives higher data rate performance. In the NBC mode, a user is served by its closest BSs, while in the DBC mode, it is served by all BSs within a given distance. However, due to the randomness of network topology, it is a challenging task to track handoffs and to characterize data rates. To address this issue, we propose a stochastic geometric analysis framework on user mobility, to derive a theoretical expression for the handoff rate experienced by an active user with arbitrary movement trajectory. Then, we characterize the average downlink user data rate under a common non-coherent joint-transmission scheme, which is used to illustrate the tradeoff between handoff rate and data rate in optimizing the cooperative cluster size. We conclude that in the NBC (resp. DBC) mode, the optimal cluster size is asymptotically inversely (resp. inversely) proportional to the square of the user speed and asymptotically inversely (resp. inversely) proportional to the BS intensity. Finally, computer simulation is conducted to validate the correctness and usefulness of our analysis.
Autors: Wei Bao;Ben Liang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 766 - 778
Publisher: IEEE
 
» Optimum Placement of UAV as Relays
Abstract:
Unmanned aerial vehicles (UAVs) as aerial base stations or relays are becoming increasingly important in communications. In this letter, the optimum placement of a relaying UAV for maximum reliability is studied. The total power loss, the overall outage, and the overall bit error rate are derived as reliability measures. The optimum altitude is investigated for both static and mobile UAVs. Numerical results show that different reliability measures have slightly different optimum altitudes and that decode-and-forward is better than amplify-and-forward.
Autors: Yunfei Chen;Wei Feng;Gan Zheng;
Appeared in: IEEE Communications Letters
Publication date: Feb 2018, volume: 22, issue:2, pages: 248 - 251
Publisher: IEEE
 
» Organizational Enablers for NPD Portfolio Selection
Abstract:
Despite substantial research that advocates the “right” portfolio of new product development initiatives for the firm, one important aspect has been overlooked: Creating a portfolio of new product development initiatives is not equivalent to choosing from a menu of initiatives. Rather, these initiatives are defined by and within the organization. Thus, portfolio selection rests upon two challenges: 1) the cross-functional nature of collaborative tasks; and 2) the role of explicit and implicit incentives on innovative outcomes. This paper explores how these factors ultimately determine the initiatives an organization pursues. We abstract a new product development organization as two functional managers who report to senior management and analyze the strategic interactions between all three stakeholders. Senior management decides whether to empower the functional managers to define the initiative and how to reward them contingent on the outcome. We evaluate how the asymmetry of information regarding each function's capability, and the explicit and implicit rewards and penalties imposed on the functional managers affect the upfront resource allocation. We find a profound effect of the information asymmetry: the set of initiatives the firm deems profitable is reduced, thus impeding the organization's potential to innovate. To counter such a shortcoming, senior management may optimally misalign the objectives of the stakeholders.
Autors: Jeremy Hutchison-Krupat;Stylianos Kavadias;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Feb 2018, volume: 65, issue:1, pages: 59 - 71
Publisher: IEEE
 
» Origin of Second-Harmonic Signals in Octave Bandwidth Traveling-Wave Tubes
Abstract:
In a helix traveling-wave tube (TWT) with a bandwidth exceeding one octave, the second harmonic of an input signal near the low end of the band will experience exponential growth. In such a case, we have found that the nonlinear electron orbits in the beam, as opposed to the orbital bunching exhibited in the linear electron orbits, are the main source for second-harmonic generation. This unexpected result is due to the synchronous amplification of the second harmonic. We demonstrate this phenomenon from the solution of the nonlinear equations that we have formulated that govern evolution of the second-harmonic field; these equations may include axial variations of the Pierce parameters. In several test cases, we compare the theory with simulation using the CHRISTINE large signal TWT code. Good agreement between theory and simulation is found.
Autors: Patrick Y. Wong;Y. Y. Lau;David Chernin;Brad W. Hoff;Ronald M. Gilgenbach;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 710 - 715
Publisher: IEEE
 
» Origins of the IEEE Edison Medal
Abstract:
The Edison Medal is one of the most prestigious awards given in the United States and Canada recognizing meritorious accomplishments in the fields of electronics and electrical engineering. The year 2009 marked the 100th anniversary of this medal named in honor of America’s most famous inventor, Thomas Alva Edison. Edison’s work exemplifies the development of large scale industrial research laboratories, the creation of new technology, and the installation of the first complete electrical systems in the 19th century. For more than a century, many important contributors to the development of electronics have received the Edison Medal over its storied history. This article outlines the origins of the Edison Medal and its legacy of honor.1
Autors: David P. Bart;Julia B. Bart;
Appeared in: Proceedings of the IEEE
Publication date: Feb 2018, volume: 106, issue:2, pages: 319 - 328
Publisher: IEEE
 
» Orthogonal Interpolation Method for Order Reduction of a Synchronous Machine Model
Abstract:
This paper introduces an interpolation method based on snapshot approach to reduce the order of a nonlinear model for magnetostatic problems and facilitate the evaluation of the corresponding system of equations. The solution of the reduced model for a set of given inputs is built by interpolating the right singular vectors, obtained from singular value decomposition of snapshots. To validate the efficiency of this method, this reduced model is compared with full-order finite-element model. Furthermore, the proposed method is analyzed with respect to a more conventional model order reduction that is combined with the discrete empirical interpolation method. The orthogonal interpolation method is the most effective method to reduce model of an interior permanent magnet synchronous machine especially in term of computational time.
Autors: Mehrnaz Farzam Far;Floran Martin;Anouar Belahcen;Laurent Montier;Thomas Henneron;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2018, volume: 54, issue:2, pages: 1 - 6
Publisher: IEEE
 
» Oscillatory TMS-EEG-Responses as a Measure of the Cortical Excitability Threshold
Abstract:
Transcranial magnetic stimulation (TMS) is a non-invasive tool to perturb brain activity. In TMS studies, the stimulation intensity (SI) is commonly normalized to the resting motor threshold (rMT) that produces muscle responses in 50% of stimulations applied to the motor cortex (M1). Since rMT is influenced by spinal excitability and coil-to-cortex distance, responses recorded from the cortex, instead of a peripheral muscle, could provide a more accurate marker for cortical excitability. Combining TMS with electroencephalography (EEG) enables the measurement of brain-wide cortical reactivity to TMS. We quantified TMS-induced changes in oscillatory power and the phase of EEG with event-related spectral perturbation (ERSP) and inter-trial coherence (ITC). We studied the SI-dependency of ERSP and ITC responses by stimulating the dominant M1 of ten healthy volunteers using single-pulse TMS with 150 pulses at 60%, 80%, 100%, and 120% of rMT. We found SI-dependent ERSP and ITC responses in M1, most notably with the wide-band (8–70 Hz) early ITC responses averaged 20–60 ms after TMS. With approximately linear SI-dependence, the early ITC response was consistent between SIs (intraclass correlation = 0.78, ). Our results reveal the potential of oscillatory EEG responses, in place of rMT, as a measure of the cortical excitability threshold in M1.
Autors: Jukka Saari;Elisa Kallioniemi;Mika Tarvainen;Petro Julkunen;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Feb 2018, volume: 26, issue:2, pages: 383 - 391
Publisher: IEEE
 
» Outage Analysis and Power Allocation in Uplink Non-Orthogonal Multiple Access Systems
Abstract:
We propose a tractable expression for the outage probability in single-cell uplink non-orthogonal multiple access (NOMA) systems serving an arbitrary number of users. The expression is obtained by approximating the inter-user interference using a shifted-gamma distributed random variable. We then formulate and propose an efficient iterative algorithm for the outage-constrained min–max power allocation problem for the NOMA system. To give a rigorous comparison, we solve the outage-constrained min–max power allocation problem for the orthogonal multiple access (OMA) counterpart where both the user power allocation and the radio resource division pattern are optimized. Simulations confirm the accuracy of the derived outage probability expression for the NOMA system. Also, we demonstrate that fairness among users in terms of transmission power can be achieved by NOMA. Moreover, NOMA can bring significant power savings to the users as compared with OMA.
Autors: Ye Liu;Mahsa Derakhshani;Sangarapillai Lambotharan;
Appeared in: IEEE Communications Letters
Publication date: Feb 2018, volume: 22, issue:2, pages: 336 - 339
Publisher: IEEE
 
» Outdoor Passive Millimeter-Wave Imaging: Phenomenology and Scene Simulation
Abstract:
A model for scene simulation is presented, which describes quantitatively the recognized phenomenology of passive millimeter-wave (PMW) imaging in land, sea, and air scenarios. The model describes objects in a scene as facets giving them electromagnetic properties from their electrical permittivities. This enables polarimetric effects in scenes to be reproduced. Illumination from the sky and ground is calculated using radiation transport, as are the emissive and absorbing effects of the atmosphere between the objects and the imager. The model includes the effects of image sampling, diffraction effects of finite imager aperture sizes, and system noise. Phenomena in experimentally acquired images in the 94 GHz atmospheric transmission window are quantified from three scenarios. These are a helicopter landing site as viewed by the pilot, a coastal region showing boats, land and buildings viewed from sea level, and an airfield viewed from directly above. These are compared quantitatively to the simulated scenes from these scenarios, finding agreement between the radiation temperatures to within a few degrees kelvin. These discrepancies are accounted for by the uncertainties in the permittivities of materials in the scene. This paper constitutes the partial validation of a scene simulation capability for PMMW imaging in outdoor scenarios.
Autors: Neil A. Salmon;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2018, volume: 66, issue:2, pages: 897 - 908
Publisher: IEEE
 
» Output-Feedback Lyapunov-Based Predictive Control of Stochastic Nonlinear Systems
Abstract:
This paper considers the problem of output-feedback control of stochastic nonlinear systems. A predictive controller is designed for which stability and feasibility (in a probabilistic sense) are guaranteed from an explicitly characterized region of attraction. The controller's performance is characterized by its risk of allowing destabilizing system behavior. Since the controller design relies on certain convergence properties of the state observer, a compatible stochastic high-gain type observer design is also presented. Finally, simulation results illustrating the efficacy of the design are presented.
Autors: Tyler Homer;Prashant Mhaskar;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Feb 2018, volume: 63, issue:2, pages: 571 - 577
Publisher: IEEE
 
» Outsourcer Knowledge Protection, Psychological Contract Schema, and Project Performance: A Vendor's Perspective
Abstract:
Despite the increased research attention directed to the importance of knowledge protection in collaborative business partnerships, such as IT offshore outsourcing, the extant literature offers conflicting views on whether knowledge protection inhibits project performance. Based on the transaction cost theory and the psychological contract theory, this study investigates how outsourcer knowledge protection affects project performance through partnership quality from the view of the vendors. Hypotheses were proposed and examined using data from 180 IT offshore outsourcing projects. This study finds that knowledge protection reduces partnership quality and project performance. Furthermore, a vendor's relational contract schema strengthens the negative effect of outsourcer knowledge protection on partnership quality, while a vendor's transactional contract schema weakens the negative effect. This study extends our understanding regarding the effects of knowledge protection on project performance and has important implications for outsourcing project management.
Autors: Zelong Wei;Zhanhe Du;Yongchuan Bao;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Feb 2018, volume: 65, issue:1, pages: 128 - 140
Publisher: IEEE
 
» Overview of Hall Electric Propulsion in China
Abstract:
Hall thruster is an attractive type of electric propulsion that is being developed to replace the chemical propulsion deployed in many tasks on satellites. The research on Hall thrusters in China has gradually progressed from basic theory to engineering applications, especially with the experience of on-orbit flight tests in low earth and geostationary equatorial orbits. This paper discusses the progress of research on Hall thrusters in China in recent years. This includes the beam focusing, scaling, high specific impulse, long lifetime, and effective magnetic field excitation techniques, as well as the stabilization technique of low-frequency oscillation, along with other types of Hall thrusters, such as cylindrical Hall, double-stage Hall, cusped field, nested-channel Hall, and anode layer Hall thrusters. In conclusion, this paper discusses the programs intended for the future focusing on the development of thrusters, their application prospects, and their use in space applications.
Autors: Ding Yongjie;Li Hong;Wei Liqiu;Hu Yanlin;Shen Yan;Liu Hui;Ning Zhongxi;Mao Wei;Yu Daren;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Feb 2018, volume: 46, issue:2, pages: 263 - 282
Publisher: IEEE
 
» Parallel Continuum Robots: Modeling, Analysis, and Actuation-Based Force Sensing
Abstract:
Parallel continuum robots (PCRs) combine the compactness, simplicity, and compliance of continuum robots with the precision and strength of rigid-link parallel robots. In this paper, we provide a generalized Cosserat-rod-based kinetostatic model framework that accommodates various joint types and problem formulations (e.g., forward and inverse kinematics under loads, and deflection-based and actuation-based force sensing) useful for simulation and control. Linearization of this general model provides the manipulator Jacobian, end-effector compliance, input stiffness, and wrench reflectivity matrices, which allow us to examine the effect of design parameters on dexterity, force application, and force-sensing ability. Using ellipsoids based on the matrices, we provide a set of design simulations and graphically depict the relationships between pose, actuation, and forces. We further provide a nondimensional analysis of the compliance of PCRs. Finally, we experimentally demonstrate and validate actuation-based force sensing on a prototype six-degree-of-freedom PCR, demonstrating 3-D force sensing with a median magnitude and a directional error of 0.23 N (8% of actual load) and 12, respectively.
Autors: Caroline B. Black;John Till;D. Caleb Rucker;
Appeared in: IEEE Transactions on Robotics
Publication date: Feb 2018, volume: 34, issue:1, pages: 29 - 47
Publisher: IEEE
 
» Parallel Electromagnetic Transients Simulation with Shared Memory Architecture Computers
Abstract:
This paper proposes a graph-based matrix level partitioning methodology for parallel electromagnetic transient (EMT) simulation. By partitioning the graph associated with the admittance matrix, an efficient bordered block diagonal matrix form is obtained, which is particularly suitable for parallel implementation. Even without the presence of distributed transmission lines, fully automatic system partitioning and parallelization of the simulation are achieved. The parallelized algorithm is implemented on a shared memory computer and assessed using two scalable test cases. The first involves an underground cable with many distributed parameter cascaded sections. The second is an interconnection of multiple instances of the IEEE 14-bus system, where only lumped transmission-line models are used. The tests show that EMT simulation can be significantly accelerated. The scalability is tested with up to 64 cores.
Autors: Shengtao Fan;Hui Ding;Anuradha Kariyawasam;Aniruddha M. Gole;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 239 - 247
Publisher: IEEE
 
» Parallel Transport Frame for Fiber Shape Sensing
Abstract:
This paper reports a reconstruction method to determine a 3-D space curve from the distributed strain by using the parallel transport frame. Parallel transport frame can efficiently eliminate the singularities and discontinuous point which appear in another existing commonly used reconstruction method Frenet Frame and thus improve the accuracy and stability of the shape sensing. To validate this method, a simulation method based on the rotation minimizing frame is proposed and used. It provides a general procedure to numerically obtain the strain distribution with a certain configuration of the shape sensor and spatial shape. Some typical space curves whose space position is analytically given are reconstructed by two reconstruction methods and the results are compared. The error sources of the reconstruction method are also analyzed.
Autors: Jiwen Cui;Shiyuan Zhao;Chaoqiang Yang;Jiubin Tan;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 12
Publisher: IEEE
 
» Parallelized Kalman Filters for Mitigation of the Excess Phase Noise of Fast Tunable Lasers in Coherent Optical Communication Systems
Abstract:
Numerical and experimental investigations are carried out on the performance of parallelized Kalman filters applied for mitigation of the excess phase noise of fast tunable lasers. Based on the characterization of the phase noise of a sampled grating distributed Bragg reflector (SG-DBR) laser, the proposed carrier phase recovery (CPR) scheme using Kalman filters is introduced. By performing simulations of data transmission with various advanced modulation formats in the presence of the excess phase noise, the Kalman filter based CPR scheme shows its ability to overcome the excess phase noise and this method is suitable for parallel processing. Then the results are further demonstrated by 12.5 Gbaud QPSK and 16-QAM transmission experiments employing the SG-DBR laser. We find that the Kalman filters have better performance than the 2nd-order phase-locked loop in parallel systems due to a better phase noise tolerance. The bit error rate performance is also examined in the whole tuning range (∼30 nm) of the tunable laser, which further proves the feasibility of the proposed scheme.
Autors: Fan Liu;Yi Lin;Yonglin Yu;Liam P. Barry;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 11
Publisher: IEEE
 
» Parallelizing Hardware Tasks on Multicontext FPGA With Efficient Placement and Scheduling Algorithms
Abstract:
Field programmable gate arrays (FPGAs) are often used to accelerate multiple tasks simultaneously, working in a tightly coupled processor-coprocessor architecture. Recently, with the fast development of emerging memory technologies, multicontext FPGAs with high-density memories that support fast dynamic reconfiguration have become feasible. Compared with single-context FPGAs, multicontext FPGAs have a much higher on-chip configuration memory capacity but have not been thoroughly investigated to exploit their capabilities. In this paper, we investigate how to best utilize the capacity advantage of the multicontext FPGAs. We first propose a static placement strategy to place the requested hardware tasks with minimal area on the FPGA. We then optimize the running time of the static placement without sacrificing its solution quality. Along with the static placement, we propose collaborated online placement and scheduling strategies to manage the actual execution and reconfiguration of hardware tasks on a multicontext FPGA. Our experiments show that the static placement algorithm generates high quality placement solutions within a short time. Starting from the static placement solution, our collaborated online placer and scheduler schedules and places simultaneous acceleration tasks and reduces the acceleration task rejection rate significantly compared to a baseline design.
Autors: Hao Liang;Sharad Sinha;Wei Zhang;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Feb 2018, volume: 37, issue:2, pages: 350 - 363
Publisher: IEEE
 
» Parametric Dependencies of Sliding Window Correlation
Abstract:
Objective: In this paper, we explore the dependence of sliding window correlation (SWC) results on different parameters of correlating signals. The SWC is extensively used to explore the dynamics of functional connectivity (FC) networks using resting-state functional MRI (rsfMRI) scans. These scanned signals often contain multiple amplitudes, frequencies, and phases. However, the exact values of these parameters are unknown. Two recent studies explored the relationship of window length and frequencies (minimum/maximum) in the correlating signals. Methods: We extend the findings of these studies by using two deterministic signals with multiple amplitudes, frequencies, and phases. Afterward, we modulate one of the signals to introduce dynamics (nonstationarity) in their relationship. We also explore the relationship of window length and frequency band for real rsfMRI data. Results: For deterministic signals, the spurious fluctuations due to the method itself minimize, and the SWC estimates the stationary correlation when frequencies in the signals have specific relationship. For dynamic relationship also, the undesirable frequencies were removed under specific conditions for the frequencies. For real rsfMRI data, the SWC results varied with frequencies and window length. Conclusion: In the absence of any “ground truth” for different parameters in real rsfMRI signals, the SWC with a constant window size may not be a reliable method to study the dynamics of the FC. Significance: This study reveals the parametric dependencies of the SWC and its limitation as a method to analyze dynamics of FC networks in the absence of any ground truth.
Autors: Sadia Shakil;Jacob C. Billings;Shella D. Keilholz;Chin-Hui Lee;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2018, volume: 65, issue:2, pages: 254 - 263
Publisher: IEEE
 
» Partial-Discharge Measuring Produces Uncertain Results: Important Quality Assesment Updates for Stator Windings
Abstract:
The petrochemical industry considers the offline partial-discharge (PD) measurement an important quality assessment for new medium-voltage motor and generator stator windings. A recent edition of American Petroleum Institute (API) Standard 541 [1] requires an instrument to be compliant with International Electrotechnical Commission (IEC) Standard 60270 [3] for PD measurements on sacrificial stator coils and proposes 100 pC for guidance on acceptance criteria until more data becomes available. Given the industry's faith in PD as an acceptance test based on a representative sample, it warrants closer scrutiny. The characteristic PD distribution pattern produced by each test instrument provides information on the origin of the discharges and, therefore, can be used to determine what type of defect has produced them. This article shows how external factors such as instrument selection, testing environment, and time interval between tests can influence PD test results.
Autors: Saeed Ul Haq;Meredith K.W. Stranges;Barry Wood;
Appeared in: IEEE Industry Applications Magazine
Publication date: Feb 2018, volume: 24, issue:1, pages: 52 - 59
Publisher: IEEE
 
» Particle in a Box: An Experiential Environment for Learning Introductory Quantum Mechanics
Abstract:
Quantum mechanics (QMs) is a foundational subject in many science and engineering fields. It is difficult to teach, however, as it requires a fundamental revision of the assumptions and laws of classical physics and probability. Furthermore, introductory QM courses and texts predominantly focus on the mathematical formulations of the subject and lay less emphasis on its conceptual understanding. Consequently, students struggle to build robust mental models of the concepts. This paper posits that games can provide an effective platform for an experiential and conceptual understanding of introductory QM. Games are particularly suitable for demonstrating QM characteristics because their repetitive nature is conducive to demonstrating probability concepts that form a core part of QM. Games can also immerse students in an engaging environment that motivates them to learn. This paper presents the design and evaluation of a digital game for learning introductory QM concepts. The evaluation of the game indicates an improvement in students’ conceptual understanding of probability. Students also reported an increase in comfort level with key concepts taught in the game.
Autors: Aditya Anupam;Ridhima Gupta;Azad Naeemi;Nassim JafariNaimi;
Appeared in: IEEE Transactions on Education
Publication date: Feb 2018, volume: 61, issue:1, pages: 29 - 37
Publisher: IEEE
 
» Passive Intermodulation Due to Conductor Surface Roughness
Abstract:
The physical mechanism of the experimentally observed dependence of passive intermodulation (PIM) in printed circuits on conductor surface roughness is studied. It is shown that electrothermal (ET) nonlinearity, arising due to heating of imperfect conductors by high-power carriers in a multicarrier system, is correlated with conductor surface roughness and has a unique signature. Carriers modulate the conductor resistivity, skin depth, and surface impedance which generate PIM products. The detailed analysis demonstrates that ET-PIM depends on the conductor resistivity, shape, and roughness profile and also on the electric and thermal properties of the substrate. Their effects on PIM are illustrated by examples of uniform microstrip lines with different conductor and substrate materials, and periodically perturbed and meandered microstrip lines.
Autors: Paolo Ansuinelli;Alexander G. Schuchinsky;Fabrizio Frezza;Michael B. Steer;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2018, volume: 66, issue:2, pages: 688 - 699
Publisher: IEEE
 
» Passive Noise Shaping in SAR ADC With Improved Efficiency
Abstract:
This brief reports a passive noise-shaping (PNS) scheme for successive approximation register (SAR) analog-to-digital converter (ADC) based on the two-step integration with passive gain and comparator gain techniques. The analysis shows that the proposed method achieves a better noise-shaping (NS) efficiency than prior arts, which enhances the noise attenuation by 14 dB. A design example is provided which further adopts the delta-sampling technique to relieve the conversion efficiency loss due to the oversampling in the NS SAR ADC. The efficiency of the proposed PNS scheme and the performance of the ADC are verified by simulation achieving a 13.2 effective number of bits with a 10-b ADC architecture and eight conversion cycles for a signal bandwidth of 2 MHz sampled at 100 MS/s. The calculated Schreier figure of merit (FoM) and Walden FoM are 176.8 dB and 16 fJ/conv.-step, respectively.
Autors: Yan Song;Chi-Hang Chan;Yan Zhu;Li Geng;Seng-Pan U;Rui Paulo Martins;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2018, volume: 26, issue:2, pages: 416 - 420
Publisher: IEEE
 
» Passive Radar Detection With Noisy Reference Channel Using Principal Subspace Similarity
Abstract:
Traditional passive radar detectors compute cross correlation of the raw data in the reference and surveillance channels. However, there is no optimality guarantee for this detector in the presence of a noisy reference. Here, we develop a new detector that utilizes a test statistic based on the cross correlation of the principal left singular vectors of the reference and surveillance signal-plus-noise matrices. This detector offers better performance by exploiting the inherent low-rank structure when the transmitted signals are a weighted periodic summation of several identical waveforms (amplitude and phase modulation), as is the case with commercial digital illuminators as well as noncooperative radar. We consider a scintillating target. We provide analytical detection performance guarantees establishing signal-to-noise ratio thresholds above which the proposed detection statistic reliably discriminates, in an asymptotic sense, the signal versus no-signal hypothesis. We validate these results using extensive numerical simulations. We demonstrate the “near constant false alarm rate (CFAR)” behavior of the proposed detector with respect to a fixed, SNR-independent threshold and contrast that with the need to adjust the detection threshold in an SNR-dependent manner to maintain CFAR for other detectors found in the literature. Extensions of the proposed detector for settings applicable to orthogonal frequency division multiplexing (OFDM), adaptive radar are discussed.
Autors: Sandeep Gogineni;Pawan Setlur;Muralidhar Rangaswamy;Raj Rao Nadakuditi;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Feb 2018, volume: 54, issue:1, pages: 18 - 36
Publisher: IEEE
 
» Patch Matching for Image Denoising Using Neighborhood-Based Collaborative Filtering
Abstract:
We consider patch matching as a recommendation system problem and introduce a new patch-matching approach using nearest neighbor-based collaborative filtering (NN-CF). Our approach involves recommending similar patches to a query patch with the help of other similar patches in a noisy image or an external database. Using user-oriented and item-oriented formulations of NN-CF, we present two variations of CF-based patch-matching criterion. To demonstrate the superior matches found with our method, we apply the new patch-matching scheme to patch-based image denoising and evaluate its effect on the denoising performance. We test the methods on two data sets with varying background and image complexities and under different levels of noise. The proposed method not only improves robustness to patch matching but also provides a new formulation to seamlessly combine internal and external denoising.
Autors: Shibin Parameswaran;Enming Luo;Truong Q. Nguyen;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Feb 2018, volume: 28, issue:2, pages: 392 - 401
Publisher: IEEE
 
» Path Finding for Maximum Value of Information in Multi-Modal Underwater Wireless Sensor Networks
Abstract:
We consider underwater multi-modal wireless sensor networks (UWSNs) suitable for applications on submarine surveillance and monitoring, where nodes offload data to a mobile autonomous underwater vehicle (AUV) via optical technology, and coordinate using acoustic communication. Sensed data are associated with a value, decaying in time. In this scenario, we address the problem of finding the path of the AUV so that the Value of Information (VoI) of the data delivered to a sink on the surface is maximized. We define a Greedy and Adaptive AUV Path-finding (GAAP) heuristic that drives the AUV to collect data from nodes depending on the VoI of their data. For benchmarking the performance of AUV path-finding heuristics, we define an integer linear programming (ILP) formulation that accurately models the considered scenario, deriving a path that drives the AUV to collect and deliver data with the maximum VoI. In our experiments GAAP consistently delivers more than 80 percent of the theoretical maximum VoI determined by the ILP model. We also compare the performance of GAAP with that of other strategies for driving the AUV among sensing nodes, namely, random paths, TSP-based paths and a “lawn mower”-like strategy. Our results show that GAAP always outperforms every other heuristic in terms of delivered VoI, also obtaining higher energy efficiency.
Autors: Petrika Gjanci;Chiara Petrioli;Stefano Basagni;Cynthia A. Phillips;Ladislau Bölöni;Damla Turgut;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Feb 2018, volume: 17, issue:2, pages: 404 - 418
Publisher: IEEE
 
» Path Planning and Collision Avoidance for a Multi-Arm Space Maneuverable Robot
Abstract:
In this paper, a path planning algorithm for a multi-arm space robot is proposed. The robot is capable of maneuvering on the exterior of a large space station. Based on the maneuver strategy, continuous and smooth trajectories of the manipulator end effectors are first determined via the polynomial interpolation method. Then, the kinematics describing the relation between the end effector and the joint angles as well as the platform are formulated. A Moore–Penrose pseudoinverse solution of the joint trajectories is calculated to describe the motion of the manipulators, particularly, considering the singularity avoidance. In addition, a collision detection algorithm is developed to estimate the security during operation. Constraints are formulated by considering collision avoidance, based on which a collision-free trajectory is optimized through the multiplier-penalty method. The numerical results of a triple-arm space robotic system are given to demonstrate the effectiveness of the proposed algorithms.
Autors: Xiaoyu Chu;Quan Hu;Jingrui Zhang;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Feb 2018, volume: 54, issue:1, pages: 217 - 232
Publisher: IEEE
 
» Performability Analysis of k-to-l-Out-of-n Computing Systems Using Binary Decision Diagrams
Abstract:
Modern computing systems typically utilize a large number of computing nodes to perform coordinated computations in parallel or simultaneously. They can exhibit multiple performance states or levels due to statuses or failures of their consistent nodes. Performability analysis is concerned with assessing the probability that the computing system performs at a particular performance level. In the context of performability analysis, these computing systems can be modeled using k-to-l-out-of-n structures. This paper proposes new analytical methods based on binary decision diagrams (BDD) for the performability analysis of large computing systems with unrepairable computing nodes. A new and efficient BDD algorithm that makes full uses of the special k -to-l-out-of-n structure is first proposed for systems with computing node having identical computing powers. New simplification rules are further proposed to generate compact and canonical BDD models for systems with heterogeneous computing nodes characterized by different computing powers. Ordering heuristic is also explored to further reduce the size of BDD models. Examples are provided to illustrate the proposed BDD-based performability analysis methodology as well as its efficiency in analyzing large-scale computing systems.
Autors: Yuchang Mo;Liudong Xing;Joanne Bechta Dugan;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Feb 2018, volume: 15, issue:1, pages: 126 - 137
Publisher: IEEE
 
» Performability Modeling for RAID Storage Systems by Markov Regenerative Process
Abstract:
This paper presents a performability model for RAID storage systems using Markov regenerative process to compare different RAID architectures. While homogeneous Markov models are extensively used for reliability analysis of RAID storage systems, the memory-less property of the sojourn time assumed in such models is not satisfied in reality, especially in disk rebuild process whose progress is not interrupted even at an event of another disk failure. In this paper, we use Markov regenerative process which allows us to model the generally distributed rebuild times providing a needed extension of the traditional Markov models. The Markov regenerative process is then used to assess the performability of the storage system by assigning reward rates to each state based on the real storage benchmark results. Our numerical study characterizes the performability advantage of RAID6 architecture over RAID10 architecture in terms of sequential read access. Our findings include that the effect of exponential assumption for the rebuild times has practically negligible effect when we focus on data availability. However, the effect this approximation on performability prediction may not be negligible especially when the performance level drastically changes in degraded states. Our MRGP model provides more accurate prediction of performability in such cases.
Autors: Fumio Machida;Ruofan Xia;Kishor S. Trivedi;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Feb 2018, volume: 15, issue:1, pages: 138 - 150
Publisher: IEEE
 
» Performance Analysis of Adaptive Detectors for Point Targets in Subspace Interference and Gaussian Noise
Abstract:
This paper investigates the statistical performance of three adaptive detectors in the presence of subspace interference and Gaussian noise. The interference is deterministic and lies in a known subspace but with unknown coordinates, while the noise is Gaussian distributed with unknown covariance matrix. For performance evaluation, we consider a more general case, namely, the case of subspace signal mismatch, where the actual signal does not completely lie in the presumed signal subspace. We derive the exact statistical distributions of the detectors, and then obtain analytical expressions for probabilities of detection and false alarm. The theoretical study reveals that the interference and signal mismatch affects the detection performance through two angles, which are the angle between the interference subspace and actual signal, and the angle between the actual signal and presumed signal subspace after they are both projected onto the interference-orthogonalized subspace. Numerical examples are provided to verify the theoretical results.
Autors: Weijian Liu;Yong-Liang Wang;Jun Liu;Lei Huang;Chengpeng Hao;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Feb 2018, volume: 54, issue:1, pages: 429 - 441
Publisher: IEEE
 
» Performance Analysis of FDD Massive MIMO Systems Under Channel Aging
Abstract:
In this paper, we study the effect of channel aging on the uplink and downlink performance of an FDD massive MIMO system, as the system dimension increases. Since the training duration scales linearly with the number of transmit dimensions, channel estimates become increasingly outdated in the communication phase, leading to performance degradation. To quantify this degradation, we first derive bounds on the mean squared channel estimation error. We use the bounds to derive deterministic equivalents of the receive SINRs, which yields a lower bound on the achievable uplink and downlink spectral efficiencies. For the uplink, we consider maximal ratio combining and MMSE detectors, while for the downlink, we consider matched filter and regularized zero forcing precoders. We show that the effect of channel aging can be mitigated by optimally choosing the frame duration. It is found that using all the base station antennas can lead to negligibly small achievable rates in high user mobility scenarios. Finally, numerical results are presented to validate the accuracy of our expressions and illustrate the dependence of the performance on the system dimension and channel aging parameters.
Autors: Ribhu Chopra;Chandra R. Murthy;Himal A. Suraweera;Erik G. Larsson;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 1094 - 1108
Publisher: IEEE
 
» Performance Analysis of Near-Optimal Energy Buffer Aided Wireless Powered Communication
Abstract:
In this paper, we consider a wireless powered communication system, where an energy harvesting (EH) node harvests energy from a radio frequency (RF) signal broadcasted by an access point (AP) in the downlink (DL). The node stores the harvested energy in an energy buffer and uses the stored energy to transmit data to the AP in the uplink (UL). We investigate two simple online transmission policies for the EH node, namely a best-effort policy and an on-off policy, which do not require knowledge of the EH profile nor channel knowledge. In particular, for both policies, the EH node transmits in each time slot with a constant desired power if sufficient energy is available in its energy buffer. Otherwise, the node transmits with the maximum possible power in the best-effort policy and remains silent in the on-off policy. For both policies, we use the theory of discrete-time continuous-state Markov chains to analyze the limiting distribution of the stored energy for finite- and infinite-size energy buffers. We provide this limiting distribution in closed form for a Nakagami- fading DL channel and analyze the outage probability for a Nakagami- fading UL channel. All derived analytical results are not limited to EH via RF WPT but are applicable for any independent and identically distributed EH process from e.g. solar and wind energy. Our results reveal that, for low-to-medium outage probabilities, the best-effort policy is superior to the on-off policy and the optimal UL transmit power of the EH node that minimizes the outage probability is always less than the average harvested power. The opposite behaviour is observed for high outage probabilities. Furthermore, we show that the minimum outage probability of the two proposed policies is near-optimal.
Autors: Rania Morsi;Diomidis S. Michalopoulos;Robert Schober;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 863 - 881
Publisher: IEEE
 
» Performance Analysis of Perfectly Matched Layers Applied to Spherical FDTD Grids
Abstract:
A numerical analysis of the performance of the spherical perfectly matched layer (PML) applied to the finite-difference time-domain (FDTD) algorithm implemented in spherical staggered grids is presented in this communication. The spherical PML is derived through a complex transformation (analytical continuation) of the radial coordinate. We evaluate the performance of the spherical PML by simulating fields produced by electric dipoles within the spherical FDTD terminated by a spherical PML and computing the reflection error. The influence of several PML parameters on the reflection error is examined.
Autors: Wentao Bao;Fernando L. Teixeira;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2018, volume: 66, issue:2, pages: 1035 - 1039
Publisher: IEEE
 
» Performance of SWIPT for AF MIMO Relay Systems With Direct Link
Abstract:
A simultaneous wireless information and power transfer scheme for amplify-and-forward relay systems with a direct source–receiver link is investigated. According to the minimum-mean-square-error criterion, we formulate a joint beamforming problem under an energy harvesting constraint at the receiver plus transmitting power constraints at source and relay. Using an iterative algorithm, the non-convex problem is decoupled into two subproblems. A successive convex approximation method with iterative algorithm is designed for obtaining the local optimum. Assuming that , we propose a simplified measure using singular value decomposition and generalized singular value decomposition techniques. Numerical results for the number of iterations and bit error rate are carried out to evaluate the performance of the three different schemes.
Autors: Zhigang Wen;Wenxia Guo;N. C. Beaulieu;Xiaoqing Liu;Wenjun Xu;
Appeared in: IEEE Communications Letters
Publication date: Feb 2018, volume: 22, issue:2, pages: 340 - 343
Publisher: IEEE
 
» Performance Study for SWIPT Cooperative Communication Systems in Shadowed Nakagami Fading Channels
Abstract:
In this paper, we investigate the performance of simultaneous wireless information and power transfer cooperative amplify-and-forward communication systems in shadowed Nakagami- fading channels. Both coherent and non-coherent modulations, namely, binary phase-shift keying (BPSK) and binary differential phase-shift keying (BDPSK) are considered. We propose closed-form expressions of the moment generating function and the probability density function for the received signal-to-noise ratio of the cooperative link. Based on this, we further derive the average bit-error-rate and the outage probability expressions for the systems with both BPSK and BDPSK modulations. All of these expressions are given in closed-form except one in single integral that can be easily evaluated using numerical integration methods. Numerical results are used to confirm the validity of the proposed analytical results. It is shown that the performance of the systems is more susceptible to the fading parameter than to the shadowing level and does not change much with the power splitting ratio.
Autors: Yizhi Feng;Victor C. M. Leung;Fei Ji;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 1199 - 1211
Publisher: IEEE
 
» Perimeter and Area Components in the ${I}$ – ${V}$ Curves of 4H-SiC Vertical p+-i-n Diode With Al+ Ion-Implanted Emitters
Abstract:
This paper describes the separation between the area and the perimeter current density components of 4H-SiC vertical p+-i-n diode with a circular Al+ implanted emitter of different diameters in the range 150– and for temperatures of measurement in the range 30–290 °C. It is shown that before the diode series resistances become dominant, the forward current is given by the sum of an area plus a perimeter component, both of exponential trend with ideality factor 2; while toward high voltages, an area component with exponential trend and ideality factor 1 adds to the previous components. Moreover, this paper shows that forward area and perimeter current density components can be used for a straightforward identification of the parameters controlling the current transport, provided that they can be fit by the p-n junction equations in the frame of the abrupt junction approximation. Finally, this paper shows that the area reverse current density can be used for the identification of the electrically active defects in the drift layer.
Autors: Roberta Nipoti;Maurizio Puzzanghera;Giovanna Sozzi;Roberto Menozzi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 629 - 635
Publisher: IEEE
 
» Person Re-Identification by Camera Correlation Aware Feature Augmentation
Abstract:
The challenge of person re-identification (re-id) is to match individual images of the same person captured by different non-overlapping camera views against significant and unknown cross-view feature distortion. While a large number of distance metric/subspace learning models have been developed for re-id, the cross-view transformations they learned are view-generic and thus potentially less effective in quantifying the feature distortion inherent to each camera view. Learning view-specific feature transformations for re-id (i.e., view-specific re-id), an under-studied approach, becomes an alternative resort for this problem. In this work, we formulate a novel view-specific person re-identification framework from the feature augmentation point of view, called Camera coR relation Aware Feature augmenTation (CRAFT). Specifically, CRAFT performs cross-view adaptation by automatically measuring camera correlation from cross-view visual data distribution and adaptively conducting feature augmentation to transform the original features into a new adaptive space. Through our augmentation framework, view-generic learning algorithms can be readily generalized to learn and optimize view-specific sub-models whilst simultaneously modelling view-generic discrimination information. Therefore, our framework not only inherits the strength of view-generic model learning but also provides an effective way to take into account view specific characteristics. Our CRAFT framework can be extended to jointly learn view-specific feature transformations for person re-id across a large network with more than two cameras, a largely under-investigated but realistic re-id setting. Additionally, we present a domain-generic deep person appearance representation which is designed particularly to be towards view invariant for facilitating cross-view adaptation by CRAFT. We conducted extensively comparative experiments to validate the- superiority and advantages of our proposed framework over state-of-the-art competitors on contemporary challenging person re-id datasets.
Autors: Ying-Cong Chen;Xiatian Zhu;Wei-Shi Zheng;Jian-Huang Lai;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Feb 2018, volume: 40, issue:2, pages: 392 - 408
Publisher: IEEE
 
» PERSON—Personalized Expert Recommendation System for Optimized Nutrition
Abstract:
The rise of personalized diets is due to the emergence of nutrigenetics and genetic tests services. However, the recommendation system is far from mature to provide personalized food suggestion to consumers for daily usage. The main barrier of connecting genetic information to personalized diets is the complexity of data and the scalability of the applied systems. Aiming to cross such barriers and provide direct applications, a personalized expert recommendation system for optimized nutrition is introduced in this paper, which performs direct to consumer personalized grocery product filtering and recommendation. Deep learning neural network model is applied to achieve automatic product categorization. The ability of scaling with unknown new data is achieved through the generalized representation of word embedding. Furthermore, the categorized products are filtered with a model based on individual genetic data with associated phenotypic information and a case study with databases from three different sources is carried out to confirm the system.
Autors: Chih-Han Chen;Maria Karvela;Mohammadreza Sohbati;Thaksin Shinawatra;Christofer Toumazou;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2018, volume: 12, issue:1, pages: 151 - 160
Publisher: IEEE
 
» PES Connections: Being Relevant to the Global Working Professional [Leader's Corner]
Abstract:
Advertisement, IEEE.
Autors: Saifur Rahman;
Appeared in: IEEE Power and Energy Magazine
Publication date: Feb 2018, volume: 16, issue:1, pages: 10 - 12
Publisher: IEEE
 
» Petri Net Siphon Analysis and Graph Theoretic Measures for Identifying Combination Therapies in Cancer
Abstract:
Epidermal Growth Factor Receptor (EGFR) signaling to the Ras-MAPK pathway is implicated in the development and progression of cancer and is a major focus of targeted combination therapies. Physiochemical models have been used for identifying and testing the signal-inhibiting potential of targeted therapies; however, their application to larger multi-pathway networks is limited by the availability of experimentally-determined rate and concentration parameters. An alternate strategy for identifying and evaluating drug-targetable nodes is proposed. A physiochemical model of EGFR-Ras-MAPK signaling is implemented and calibrated to experimental data. Essential topological features of the model are converted into a Petri net and nodes that behave as siphons—a structural property of Petri nets—are identified. Siphons represent potential drug-targets since they are unrecoverable if their values fall below a threshold. Centrality measures are then used to prioritize siphons identified as candidate drug-targets. Single and multiple drug-target combinations are identified which correspond to clinically relevant drug targets and exhibit inhibition synergy in physiochemical simulations of EGF-induced EGFR-Ras-MAPK signaling. Taken together, these studies suggest that siphons and centrality analyses are a promising computational strategy to identify and rank drug-targetable nodes in larger networks as they do not require knowledge of the dynamics of the system, but rely solely on topology.
Autors: Behnam Behinaein;Karen Rudie;Waheed Sangrar;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Feb 2018, volume: 15, issue:1, pages: 231 - 243
Publisher: IEEE
 
» Phase Noise Influence in a Dual-Frequency Laser Phase-Shift Range Finder
Abstract:
The influence of phase noise in a dual-frequency laser phase-shift range finder is theoretically and experimentally investigated. The proposed range finder is based on the use of a coherent dual-frequency laser and direct detection of the backscattered laser. The effects of laser phase noise and noise from an acousto-optic frequency shifter (AOFS) on the dual-frequency laser phase-shift range finder are analyzed. Expressions of the power spectral density and the phase noise of the dual-frequency laser beat note are deduced. In addition, we find that noise from the AOFS has a considerable impact on beat note noise conversion. The theoretical results can be used to estimate the influence of laser phase noise, noise induced by the AOFS and delay length in the dual-frequency laser range finder. An experiment involving the dual-frequency laser range finder is performed on outdoor targets at a distance of 200 m, and the phase jitter observed in the experiment is in good agreement with the model of beat note phase noise.
Autors: Hongzhi Yang;Changming Zhao;Haiyang Zhang;Suhui Yang;Xinyuan Zheng;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 10
Publisher: IEEE
 
» Phase Retrieval for Digital Holographic Microscopy With Defocused Holograms
Abstract:
A new phase retrieval technique in digital holographic microscopy (DHM) with three defocused holograms is proposed. Given the defocusing distance, the phase distributions of tested specimen can be reconstructed with a simple algebraic equation. We have deduced this equation in detail. To avoid the manual operation, the defocused holograms can be flexibly and precisely obtained by introducing an electronically tunable lens based 4f system. This method is suitable for an on-axis hologram as well as the off-axis one but avoids the requirements for not only the iterative process, complex spectrum selection in off-axis DHM or additional phase-shifting devices in on-axis DHM but also the assumption of tested specimen or previous knowledge of the system. A series of simulations and the experimental results of the microlens array and water drop demonstrate the feasibility and effectiveness of the proposed method.
Autors: Dingnan Deng;Weijuan Qu;Wenqi He;Yu Wu;Xiaoli Liu;Xiang Peng;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 9
Publisher: IEEE
 
» Phase Retrieval Utilizing Particle Swarm Optimization
Abstract:
Phase retrieval is an important tool for image recovery techniques based on Fourier spectrum. Different iterative algorithms have been developed to retrieve phase information. However, due to the nonconvex feature of the phase optimization problem, it remains a challenge to globally obtain the optimal phase information. In this work, we proposed an iterative algorithm to retrieve the global optimal phase information by adopting particle swarm optimization technique to the hybrid input–output scheme. By escaping the local minima using stochastic perturbations and information exchange among particles’ local solutions, the proposed scheme increases the possibility of reaching the global minimum in phase retrieval optimization. In the numerical simulations, the images reconstructed by the proposed scheme have an averaged mean-square error of 0.0055, which is, respectively, 43.88% and 36.78% smaller than those of the images reconstructed by hybrid input–output and guided hybrid input–output schemes. The feasibility of the proposed scheme was demonstrated by the results from actual experiments, which showed an agreement with the simulation. The proposed scheme is statistically capable of obtaining accurate phase information, and, therefore, can be applied to Fourier spectrum based image recovery techniques.
Autors: Li-Jing Li;Teng-Fei Liu;Ming-Jie Sun;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 9
Publisher: IEEE
 
» Phase-Stabilized W-Band Planar Imaging System for Near-to-Far-Field Projection Based on Photonic Sensors
Abstract:
This letter presents a highly stabilized planar near-field imaging system for millimeter-wave antenna characterization based on dual electrooptic sensors. The issue of system instability, which often occurs in millimeter-wave sensing, is effectively eliminated by employing error correction techniques with field-calibrated probes. This technique compensates for the phase vibration of a radio frequency source by using an additional reference probe. Detailed stabilization techniques for the phase drift are discussed. A probe is also field-calibrated on the W-band so as to provide electric field imaging with the absolute value. W-band horn antenna characterization at 95 GHz is conducted, and the absolute field distribution is compared using the proposed system and a conventional electrical near-field system. A simulation is also conducted. The radiation far-field pattern and gain, calculated from the near-field measurements, are in good agreement with each other according to a comparison of these outcomes. Moreover, a back-projection algorithm with a far electric field as input is utilized to reconstruct the aperture fields of a horn antenna. Finally, a comparison between the measured and reconstructed near-field data with different distances between the probe and the horn antenna is made.
Autors: Young-Pyo Hong;Dong-Joon Lee;No-Weon Kang;Hyunji Koo;
Appeared in: IEEE Antennas and Wireless Propagation Letters
Publication date: Feb 2018, volume: 17, issue:2, pages: 315 - 318
Publisher: IEEE
 
» Photonic Microwave Frequency Measurement Based on Frequency-Configurable Pilot Tones
Abstract:
A photonic technique for microwave frequency measurement with flexible range and high resolution is proposed based on frequency-configurable pilot tones. The method extracts the remote unknown microwave frequency by measuring electrical power at two known pilot frequencies, avoiding dual-channel photodetection and broadband microwave power measurement over the whole interested frequency range. Moreover, it enables flexible measurement range by configuring two pilot frequencies. A proof-of-concept experiment is successfully demonstrated with the frequency range of 6–18.9 GHz and the resolution of 0.1 GHz.
Autors: Heng Wang;Shangjian Zhang;Xinhai Zou;Zhiyao Zhang;Yali Zhang;Yong Liu;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2018, volume: 30, issue:4, pages: 363 - 366
Publisher: IEEE
 
» Physics Model-Based Scatter Correction in Multi-Source Interior Computed Tomography
Abstract:
Multi-source interior computed tomography (CT) has a great potential to provide ultra-fast and organ-oriented imaging at low radiation dose. However, X-ray cross scattering from multiple simultaneously activated X-ray imaging chains compromises imaging quality. Previously, we published two hardware-based scatter correction methods for multi-source interior CT. Here, we propose a software-based scatter correction method, with the benefit of no need for hardware modifications. The new method is based on a physics model and an iterative framework. The physics model was derived analytically, and was used to calculate X-ray scattering signals in both forward direction and cross directions in multi-source interior CT. The physics model was integrated to an iterative scatter correction framework to reduce scatter artifacts. The method was applied to phantom data from both Monte Carlo simulations and physical experimentation that were designed to emulate the image acquisition in a multi-source interior CT architecture recently proposed by our team. The proposed scatter correction method reduced scatter artifacts significantly, even with only one iteration. Within a few iterations, the reconstructed images fast converged toward the “scatter-free” reference images. After applying the scatter correction method, the maximum CT number error at the region-of-interests (ROIs) was reduced to 46 HU in numerical phantom dataset and 48 HU in physical phantom dataset respectively, and the contrast-noise-ratio at those ROIs increased by up to 44.3% and up to 19.7%, respectively. The proposed physics model-based iterative scatter correction method could be useful for scatter correction in dual-source or multi-source CT.
Autors: Hao Gong;Bin Li;Xun Jia;Guohua Cao;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2018, volume: 37, issue:2, pages: 349 - 360
Publisher: IEEE
 
» Physics-Based Compact TDDB Models for Low- $k$ BEOL Copper Interconnects With Time-Varying Voltage Stressing
Abstract:
Time-dependent dielectric breakdown (TDDB) is one of the important failure mechanisms for copper (Cu) interconnects. This problem becomes more severe as the pitch between wires is shrinking and low- dielectric materials (low electrical and mechanical strength) are used. Many TDDB models have been proposed based on different physics kinetics in the past. Recently, a physics-based TDDB model, which is based on the breakdown concept of electric path generation, has been proposed and has shown advantage over widely accepted existing electrostatic field-based TDDB assessment. However, determination of the time-to-failure from this model includes time-consuming finite-element method (FEM). In this paper, we try to mitigate this problem by developing fast time to failure evaluation method based on the closed form solution of the ion diffusion partial differential equations. We show that the location of the minimum concentration can be determined by the dominant terms with sufficient accuracy and the time to failure can also be computed with a few dominant terms. On top of this, we also consider the time-varying stressing voltages, which is commonly seen in practical VLSI chips. We propose to develop the equivalent dc stressing voltage, which is parameterized in terms of amplitude, duty cycle, and period for periodic stressing voltage waveforms using regression-based method. We further validate the proposed analytic TDDB concentration and time to failure formula, and the equivalent dc stressing voltage compact model against the results of an FEM analysis using COMSOL. Numerical results further show that the new compact TDDB model can lead to three orders of magnitude speedup with less than 1% error against the existing FEM results.
Autors: Shaoyi Peng;Han Zhou;Taeyoung Kim;Hai-Bao Chen;Sheldon X.-D. Tan;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2018, volume: 26, issue:2, pages: 239 - 248
Publisher: IEEE
 
» Piecewise Variable Parameter Loss Model of Laminated Steel and Its Application in Fine Analysis of Iron Loss of Inverter-Fed Induction Motors
Abstract:
Due to the coaction of supply harmonics and the harmonics resulting from the motor structures, the mechanism and distribution characteristics of iron losses become more complicated in inverter-fed induction motors. Therefore, accurate prediction and fine analysis of iron loss are very important at the design stage of high-efficiency inverter-fed induction motors. In order to predict the iron losses accurately, this paper proposes a piecewise iron loss model whose parameters vary with the magnitude and frequency of flux density, and two additional flux density terms are introduced to the classical iron loss model considering the nonlinearity of magnetic material and harmonic fields. With this model, the iron losses are calculated for an inverter-fed 5.5 kW induction motor. The results reveal the distribution characteristics of hysteresis and eddy current losses in stator and rotor cores, and the characteristics of additional iron loss caused by harmonic fields. By the comparison of predicted and measured no-load iron loss under different supply voltages and switching frequencies, the proposed model and the analysis results are validated.
Autors: Zhao Haisen;Zhang Dongdong;Wang Yilong;Zhan Yang;Xu Guorui;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 832 - 840
Publisher: IEEE
 
» Piezoelectric Membrane Actuators for Micropump Applications Using PVDF-TrFE
Abstract:
This paper presents the design, fabrication, and performance evaluation of a biocompatible piezoelectric membrane actuator (PMA) using polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE). Electrode structure optimization was verified by a finite element method simulation software. Fabrication was done utilizing only standard microfabrication techniques. 1--thick membrane and 1.5--thick actuator layers were formed by spin coating using PVDF-TrFE. The surface roughness of the fabricated film was measured as 7.9 nm using a tabletop atomic force microscope (AFM) and remnant polarization at 200 V was measured as 5.38 /cm2. Deflection measurements were performed with an Al coated tipless AFM probe using a precision nano displacement system, which consists of a ferroelectric tester, a table top AFM, and a computer. A 432 nm displacement was obtained at 9 V under non-resonant conditions from a PMA with 2250 diameter. Since all moving structures were fabricated from a polymer material, high displacements could be obtained without fracture. The results demonstrated that the proposed PMA can be a good candidate for membrane type micropumps, especially to be used in biomedical applications, where low driving voltage and biocompatibility are required. [2017-0128]
Autors: Yagmur Akin Yildirim;Alperen Toprak;Onur Tigli;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Feb 2018, volume: 27, issue:1, pages: 86 - 94
Publisher: IEEE
 
» Piezoelectric Rainfall Energy Harvester Performance by an Advanced Arduino-Based Measuring System
Abstract:
This paper presents the performances of rainfall energy harvesting through the use of a piezoelectric transducer and an Arduino-based measuring system. Different studies agree on the possibility of generating electricity from rainfall, but to date, a study on measuring the quantity of energy produced during rainfall is still missing. The present study begins with results obtained from laboratory researchers using piezoelectric transducers and oscilloscopes, finalized to measure the energy produced from a single raindrop, and concludes with an ad hoc Arduino-based measuring system, aimed to measure the actual amount of electrical energy produced by a piezoelectric transducer that is exposed to rainfall of variable durations.
Autors: Gianluca Acciari;Massimo Caruso;Rosario Miceli;Luca Riggi;Pietro Romano;Giuseppe Schettino;Fabio Viola;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 458 - 468
Publisher: IEEE
 
» Placement Delivery Array Design Through Strong Edge Coloring of Bipartite Graphs
Abstract:
The technique of coded caching proposed by Madddah-Ali and Niesen is a promising approach to alleviate the load of networks during peak-traffic times. Recently, placement delivery array (PDA) was presented to characterize both the placement and delivery phase in a single array for the centralized coded caching algorithm. In this letter, we reinterpret PDA from a new perspective, i.e., the strong edge coloring of bipartite graph (bigraph). We prove that, a PDA is equivalent to a strong edge colored bigraph. Thus, we can construct a class of PDAs from existing structures in bigraphs. The class subsumes the scheme proposed by Maddah-Ali et al. and a more general class of PDAs proposed by Shangguan et al. as special cases.
Autors: Qifa Yan;Xiaohu Tang;Qingchun Chen;Minquan Cheng;
Appeared in: IEEE Communications Letters
Publication date: Feb 2018, volume: 22, issue:2, pages: 236 - 239
Publisher: IEEE
 
» Planar Multifrequency Wideband Bandpass Filters With Constant and Frequency Mappings
Abstract:
A new planar filter design technique with constant and frequency mappings has been proposed for multifrequency wideband bandpass filters (BPFs). The constant mapping treats components in the circuit (e.g., frequency invariant admittances, capacitors, and ideal inverters) as frequency dependent. It is consistent with practical planar circuits and caters to a wide frequency range. Following the classic single-to-multiband transformation, a new frequency mapping function is proposed by incorporating this constant mapping idea. With these two mapping functions, a direct relation between the circuit and its microstrip counterpart is established. Therefore, the multifrequency wideband BPF is readily designed from a lowpassing circuit to the transmission line circuit. A ladder-type Chebyshev filter and a trisection filter with the general Chebyshev response have been designed as examples. The first one is a dual-band case exhibiting a wide bandwidth for each passband. The second filter is a triple-band one showing a large frequency ratio between the first and third passband. Both examples experimentally validate the proposed constant and frequency mapping technique.
Autors: Runqi Zhang;Dimitrios Peroulis;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2018, volume: 66, issue:2, pages: 935 - 942
Publisher: IEEE
 
» Planar Multiple-Antiparallel Square Transmitter for Position-Insensitive Wireless Power Transfer
Abstract:
In this letter, a new kind of transmitter for uniform magnetic field distribution over relatively long-distance wireless charging plane is proposed. The transmitting coil is composed of multiple series square windings. Each winding consists of a set of concentric square loops. The spiral directions of two adjacent windings are opposite. The theoretical analysis shows, compared with conventional unidirectional square spiral coil, the proposed multiple-antiparallel square spiral coil can effectively enhance the height of the charging plane with uniform magnetic field. Furthermore, two planar wireless power transfer (WPT) systems adopting the proposed and conventional square transmitters are set up. The charging height is 5 cm. The ratio between the charging height and the transmitter's side length is 0.25. The experimental results show that, owing to the better uniform magnetic field produced by the proposed transmitter, the maximum transfer efficiency without coil misalignment is 91.4%. The reduced efficiency is less than 3% regardless of the location of the receiver. Additionally, the load power significantly maintains stability compared with the case of the conventional coil. As a result, the proposed coil can be a good candidate for practical planar WPT applications.
Autors: Shengming Wang;Zhaoyang Hu;CanCan Rong;Conghui Lu;Junfeng Chen;Minghai Liu;
Appeared in: IEEE Antennas and Wireless Propagation Letters
Publication date: Feb 2018, volume: 17, issue:2, pages: 188 - 192
Publisher: IEEE
 
» Plasmonic Magnetic Sensor Based on Graphene Mounted on a Magneto-Optic Grating
Abstract:
In this paper, we propose a magnetic sensor utilizing the non-reciprocal propagation of surface plasmons (SPs) on a graphene layer mounted on a magneto-optic grating. An incident electromagnetic wave upon the graphene layer can be absorbed and, under certain conditions, coupled to the SPs along the layer. The sensor structure is assumed to be parallel to the applied magnetic field, the parameter which should be sensed and measured. Contrary to the case with no magnetic field bias and due to magneto-optic characteristics of the grating substrate, wave absorbance for each incident mode can be realized in two different frequencies with non-reciprocal behavior. The frequency difference between these distinct modes depends on the applied magnetic field. This idea can provide a proper approach to sense and measure the magnitude of the applied magnetic field. The performance of the proposed structure is studied analytically and confirmed by numerical simulations. The sensor can be utilized extensively in various systems employing the magnetic field capabilities such as medical diagnostic devices and physicists’ experimental setups.
Autors: Alireza Dolatabady;Nosrat Granpayeh;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2018, volume: 54, issue:2, pages: 1 - 5
Publisher: IEEE
 
» Plasmonic Refractive Index Sensor Employing Niobium Nanofilm on Photonic Crystal Fiber
Abstract:
This letter presents a numerical investigation of a highly sensitive refractive index sensor based on surface plasmon resonance. An ultrathin niobium nanofilm is proposed as a new plasmonic material, which outperforms existing plasmonic materials. This nanofilm is employed on a photonic crystal fiber for the first time resulting sensing over a wide range of refractive indices. Finite-element method-based numerical analysis shows that maximum amplitude sensitivity of 1560 RIU and wavelength sensitivity of 8000 nm/RIU can be obtained for an analyte index of 1.40. A thin aluminum oxide (Al2O3) film is deposited on the outer layer of niobium film to enhance the coupling strength and in order to tune the resonance wavelength. Moreover, the effects of varying thickness of niobium nanofilm and Al2O3 film on sensing performance are also discussed. The proposed niobium nanofilm based sensor can be potentially implemented in biochemical and organic chemical sensing.
Autors: Md. Rabiul Hasan;Sanjida Akter;Kawsar Ahmed;Derek Abbott;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2018, volume: 30, issue:4, pages: 315 - 318
Publisher: IEEE
 
» Plasmonic Stripes in Aqueous Environment Co-Integrated With Si3N4 Photonics
Abstract:
We demonstrate the design, fabrication, and the experimental characterization of gold-based plasmonic stripes butt-coupled with low-pressure-chemical-vapor-deposition (LPCVD)-based Si3N4 waveguides for the excitation of surface-plasmon-polariton (SPP) modes in aqueous environment. Plasmonic gold stripes, in aqueous environment, with cross-sectional dimensions of 100 nm × 7 μm were interfaced with 360 nm × 800 nm Si3N4 waveguides cladded with low-temperature-oxide, exploiting linear photonic tapers with appropriate vertical (VO) and longitudinal (LO) offsets between the plasmonic and photonic waveguide facets. An interface insertion loss of 2.3 ± 0.3 dB and a plasmonic propagation length ( ) of 75 μ m have been experimentally measured at 1.55 μm for a VO of 400 nm and an LO of 500 nm, with simulation results suggesting high tolerance to VO and LO misalignment errors. The proposed integration approach enables seamless co-integration of plasmonic stripes, in aqueous environment, with a low-loss and low-cost LPCVD-based Si3N4 waveguide platform, revealing its strong potential for future employment in biochemical sensing applications.
Autors: George Dabos;Dimitra Ketzaki;Athanasios Manolis;Laurent Markey;Jean Claude Weeber;Alain Dereux;Anna Lena Giesecke;Caroline Porschatis;Bartos Chmielak;Dimitris Tsiokos;Nikos Pleros;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 8
Publisher: IEEE
 
» Playout Continuity Driven Framework for HTTP Adaptive Streaming Over LTE Networks
Abstract:
HyperText Transfer Protocol (HTTP) adaptive streaming (HAS) has undoubtedly become the most cost-effective solution in delivering video contents over the IP networks. While many works have been proposed to improve the performance of HAS, the HAS in the cellular networks is still a challenging problem due to the limited radio resource and the dramatically increasing need for the mobile video service. Specifically, the main problem comes from the incongruous behaviors between rate adaptation and resource allocation. The centralized scheme is a good choice to solve this problem, which determines rate adaptation of all the clients at the base station. However, the existing schemes still have three main weaknesses: 1) poor performance in playout continuity; 2) synchrony in requesting; and 3) low efficiency of radio resource. In this paper, a playout continuity driven framework (PCDF) is proposed to tackle all these drawbacks. First of all, an optimization problem is formulated to optimize the multiclient HAS over long-term evolution network. Then, a PCDF is proposed to solve the problem, which consists of three main features. First, a requesting set is defined to make clients request in a partially synchronous manner, which can not only eliminate the drawback of synchrony but also take advantage of the centralized manner. Second, we propose a two-step resource allocation scheme, of which the two steps work in different temporal scales and cooperate to improve the efficiency of radio resource. Third, with the requesting set and resource allocation, the original optimization problem can be simplified, while it is still NP hard. To solve the problem, we propose a dynamic programming approach, with which the optimal solution can be obtained in polynomial time. Moreover, a greedy algorithm is proposed to decrease the complexity. The experimental results of PCDF demonstrate that the proposed framework can both effectively shorten the playout interrupti- n duration and improve the frame quality in various circumstances.
Autors: Yuchen Chen;Guizhong Liu;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Feb 2018, volume: 28, issue:2, pages: 468 - 482
Publisher: IEEE
 
» Pokemon GO: Where VR and AR Have Gone Since Its Inception
Abstract:
Augmented reality (AR), virtual reality (VR), and mixed reality (MR) are the technologies of the future. At the same time, they remain a bit of a mystery to many people.
Autors: Melina Druga;
Appeared in: IEEE Potentials
Publication date: Feb 2018, volume: 37, issue:1, pages: 23 - 26
Publisher: IEEE
 
» Polarization Beam Splitter Based on MMI Coupler With SWG Birefringence Engineering on SOI
Abstract:
We demonstrate a novel polarization beam splitter (PBS) based on a subwavelength grating (SWG) multimode interference (MMI) coupler for the silicon-on-insulator platform. The birefringence of the MMI coupler is engineered using SWG, which leads to a compact design footprint, with a device length of less than . Our PBS has simulated extinction ratios (ERs) better than 20 dB for both polarizations over the wavelength range from 1530 to 1625 nm that covers the entire - and -bands. The fabricated device achieves the measured ERs larger than 20 dB at the wavelength of 1550 nm for both polarizations, and the insertion losses of 1.9 and 2.5 dB for the transverse electric (TE) and transverse magnetic (TM) polarizations, respectively, at 1550 nm. In addition, the measured ERs are larger than 14.5 dB for the TE polarization and 11.7 dB for the TM polarization over an 84-nm spectral range covering the entire -band.
Autors: Luhua Xu;Yun Wang;Amar Kumar;David Patel;Eslam El-Fiky;Zhenping Xing;Rui Li;David V. Plant;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2018, volume: 30, issue:4, pages: 403 - 406
Publisher: IEEE
 
» Positive and Negative Label Propagations
Abstract:
This paper extends the state-of-the-art label propagation (LP) framework in the propagation of negative labels. More specifically, the state-of-the-art LP methods propagate information of the form “the sample should be assigned the label .” The proposed method extends the state-of-the-art framework by considering additional information of the form “the sample should not be assigned the label .” A theoretical analysis is presented in order to include negative LP in the problem formulation. Moreover, a method for selecting the negative labels in cases when they are not inherent from the data structure is presented. Furthermore, the incorporation of negative label information in two multigraph LP methods is presented. Finally, a discussion on the proposed algorithm extension to out of sample data, as well as scalability issues, is presented. Experimental results in various scenarios showed that the incorporation of negative label information increases, in all cases, the classification accuracy of the state of the art.
Autors: Olga Zoidi;Anastasios Tefas;Nikos Nikolaidis;Ioannis Pitas;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Feb 2018, volume: 28, issue:2, pages: 342 - 355
Publisher: IEEE
 
» Post-CCA and Reinforcement Learning Based Bandwidth Adaptation in 802.11ac Networks
Abstract:
The new 802.11ac standard aims at achieving Gbps data throughput for individual users by exploiting enhanced physical-layer features, such as higher modulation levels, Multiple Input Multiple Output (MIMO), and wider bandwidths. However, the heterogeneity of bandwidth in a network can cause asymmetric interferences in which certain transmissions cannot be sensed by some other nodes. As a result, the conventional Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may not work well in 802.11ac networks. We call this the Hidden Channel (HC) problem, which is shown to be real via experiments with USRP and WARP boards. To solve this problem, we propose bandwidth adaptation based on post-CCA, which is a clear channel assessment (CCA) procedure performed after completing a transmission. Post-CCA in wireless networks helps mimic the CSMA with Collision Detection (CSMA/CD) mechanism in the wired Ethernet, thus enhancing channel assessment capability. Using post-CCA, we propose Post-CCA based Bandwidth Adaptation (PoBA) that alters bandwidth and channel configuration dynamically by applying a reinforcement learning mechanism. Post-CCA and PoBA do not require any hardware modification and are also compliant with the 802.11 standards. PoBA is shown via simulation to increase network-wide throughput, channel utilization and fairness, and also lower packet error probability.
Autors: Seowoo Jang;Kang G. Shin;Saewoong Bahk;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Feb 2018, volume: 17, issue:2, pages: 419 - 432
Publisher: IEEE
 
» Power Capacitor Temperature Measurement System Using FBG Sensors and Its Validation
Abstract:
It is difficult to accurately measure internal temperature of power capacitor. To accurately measure internal and external temperatures of an operating capacitor, a capacitor temperature measurement system based on fiber Bragg grating (FBG) temperature sensors is developed. First, technical parameters of the sensors and the optical sensing interrogator are determined according to the practical situations. Second, the sensors are calibrated using a highly accurate thermostatic bath, and their reproducibility is checked. Third, in combination with ENLIGHT software, the temperature measurement system based on FBG sensors is set up. Finally, three BAM6.56-556-1W high-voltage film capacitors are manufactured, and the FBG sensors are put into a high-voltage film capacitor and placed on its shell, the temperature distribution of the capacitor in the thermal stability test is measured. The corresponding temperature field model of the capacitor under the same conditions is created and solved in Fluent. The simulation results are consistent with the measured results, which validates the temperature measurement system. This paper fixes the problem of internal temperature measurement for high-voltage film capacitor which can be taken as a reference to online monitoring of power capacitor temperature.
Autors: Zijian Wang;Zhiniu Xu;Lijuan Zhao;Saifei Han;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Feb 2018, volume: 67, issue:2, pages: 449 - 458
Publisher: IEEE
 
» Power Control by GDoF Duality of Treating Interference as Noise
Abstract:
In this letter, we revisit the duality of treating interference as noise from the generalized degrees-of-freedom (GDoF) perspective. Specifically, in a general -user interference channel, where interference is treated as Gaussian noise, we demonstrate, for any given GDoF tuple and its power allocation, how to derive a power allocation that yields a dominant GDoF tuple in its reciprocal channel. This finding naturally leads to a fast iterative GDoF-duality-based power control algorithm. Numerical results show that the proposed algorithm achieves competitive sum-rate performance with sophisticated signal-to-interference-plus-noise ratio-based power control scheme.
Autors: Chunhua Geng;Syed A. Jafar;
Appeared in: IEEE Communications Letters
Publication date: Feb 2018, volume: 22, issue:2, pages: 244 - 247
Publisher: IEEE
 
» Power Control for Multi-Cell Networks With Non-Orthogonal Multiple Access
Abstract:
In this paper, we investigate the problems of sum power minimization and sum rate maximization for multi-cell networks with non-orthogonal multiple access. Considering the sum power minimization, we obtain closed-form solutions to the optimal power allocation strategy and then successfully transform the original problem to a linear one with a much smaller size, which can be optimally solved by using the standard interference function. To solve the nonconvex sum rate maximization problem, we first prove that the power allocation problem for a single cell is a convex problem. By analyzing the Karush–Kuhn–Tucker conditions, the optimal power allocation for users in a single cell is derived in closed form. Based on the optimal solution in each cell, a distributed algorithm is accordingly proposed to acquire efficient solutions. Numerical results verify our theoretical findings showing the superiority of our solutions compared with the orthogonal frequency division multiple access and broadcast channel.
Autors: Zhaohui Yang;Cunhua Pan;Wei Xu;Yijin Pan;Ming Chen;Maged Elkashlan;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 927 - 942
Publisher: IEEE
 
» Power Loading in Peak Limited Intensity Modulation Direct Detection Mode Group Division Multiplexing
Abstract:
The exponential growth of network traffic within data centers and high-performance computing generates a growing volume of fiber cabling. This raises the need for spectrally efficient communication scheme, which allows easy integration of optics and electronics. In this paper, we suggest a mode group division multiplexing scheme based upon intensity-modulated silicon photonics (SiP) Mach–Zehnder modulators (MZMs) coupled to standard graded-index multi-mode fiber directly detected using multi-segment concentric photo-detector. In addition, we have theoretically derived the bit and power loading of such a system in a closed-loop multiple-input multiple-output (MIMO) formation using convex optimization with two possible types of architectures: the vertical Bell Labs layered space-time architecture (V-BLAST) with minimum mean square error and successive interference cancellation (MMSE-SIC); and singular value decomposition (SVD). Our optimization problem maximizes the system's capacity under peak amplitude, power consumption, and BER constraints. Simulation results have shown the superiority of a V-BLAST MMSE-SIC over the SVD architecture in terms of total spectral efficiency for a 4 × 4 MIMO short reach low driving voltage conventional SiP-based MZM system.
Autors: Nir Sheffi;Dan Sadot;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 24
Publisher: IEEE
 
» Power Quality Improvement of Grid-Connected DC Microgrids Using Repetitive Learning-Based PLL Under Abnormal Grid Conditions
Abstract:
This paper proposes a repetitive learning-based phase locked loop (RLPLL) to improve power quality of the grid-connected dc microgrids under distorted grid voltage in a weak grid. The harmonic component present in grid current in a high impedance network amplifies the distortion in voltage, which often leads to instability. Since the behavior of the conventional synchronous reference frame PLL (SRF-PLL) varies, owing to the proportional-integral gains constrained to harmonic rejection bandwidth ultimately leading to a sluggish response. However, RLPLL accommodates this limitation with a comparable dynamic performance and enhanced harmonic attenuation properties. This has been achieved by using a Lyapunov-based approach for harmonic estimation, which facilitates the periodicity and boundedness of the harmonic component to obtain an adaptive learning-based update. To deal with the computational burden, this paper also provides a low-computing alternative model of the proposed strategy. The dynamic response of RLPLL along with a comparative analysis with SRF-PLL is governed by many events directly affecting the dc voltage, which is critical for the operation of dc microgrids. Its performance is validated under different scenarios in a 1-kVA field programmable gate array-based experimental setup.
Autors: Subham Sahoo;Surya Prakash;Sukumar Mishra;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 82 - 90
Publisher: IEEE
 
» Power Quality Investigation in Ceramic Insulator
Abstract:
This paper presents a new method for the detection of high-voltage flashover using the power quality parameters in the insulator testing industries at a remote location from the test rig. In ceramic insulator industries, it is mandatory to test each insulator at manufacturing stage for high-voltage power frequency flashover/withstand test. The flashover is visually detected by the operator in insulator industries. Therefore, an operator has to be physically present close to the testing rig for the detection of flashover, which is very dangerous for the life. The proposed “high-voltage flashover detector” detects the flashover in insulators without using any quantity required to be measured from the high-voltage side of the test rig. The proposed scheme provides an improved flashover detection system, which detects the flashover without its visual inspection. The flashover phenomenon is reliably detected at some distant location from the test rig using power quality parameters of the system. The detailed power quality analysis of high-voltage ceramic insulator industries during power frequency flashover test and lightning impulse test based on experimental investigation is also reported here. Initially, a prototype of the new method for detection of high-voltage flashover is designed and implemented for flashover detection in insulator industries and in test laboratories. This scheme may also be extended to detect the fault on hot line with required modifications.
Autors: Ujjwal Kumar Kalla;Rakhi Suthar;Kunal Sharma;Bhim Singh;Jaiwin Ghotia;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 121 - 134
Publisher: IEEE
 
» Power to the People?: What It Means to the Changing Energy Landscape [In My View]
Abstract:
Is it true that the shift to cleaner, more sustainable forms of energy is “empowering” energy consumers, putting them at the center of the new, greener energy system of the future? Is power really seeping away from the giant energy behemoths of the past to the nimble, green-energy prosumers and cooperatives of the future? In the face of today's energy landscape, still dominated by relatively few large, centrally structured energy utilities and system operators, these claims may seem overblown. But the energy landscape is changing, and this has major implications for energy research: the transition to a decentralized, lowcarbon energy system powered mainly by renewables-which has only just begun-really does open new horizons for energy consumers and energy citizens alike (an important distinction to which I will return). As they come to grips with these changes, energy researchers must not lose sight of the profoundly disempowering effects of energy poverty and a lack of alternatives for carbon-intensive regions, which can prolong the inevitable exit from the dirty fossil fuels of the past.
Autors: Gerd Schonwalder;
Appeared in: IEEE Power and Energy Magazine
Publication date: Feb 2018, volume: 16, issue:1, pages: 76 - 72
Publisher: IEEE
 
» Power-Aware Optimized RRH to BBU Allocation in C-RAN
Abstract:
Wireless networks have faced increasing demand to cope with the exponential growth of data. Conventional architectures have hindered the evolution of network scalability. However, the introduction of cloud technology has brought tremendous flexible and scalable on demand resources. Thus, cloud radio access networks (C-RANs) have been introduced as a new trend in wireless technologies. Despite the novel advancements that C-RAN offers, remote radio head (RRH)-to-base band unit (BBU) resource allocation can cause significant downgrade in efficiency, particularly the allocation of computational resources in the BBU pool to densely deployed small cells. This causes an increase in power consumption and wasted resources. Consequently, an efficient resource allocation method is vital for achieving efficient resource consumption. In this paper, the optimal allocation of computational resources between RRHs and BBUs is modeled. This is dependent on having an optimal physical resource allocation for users to determine the required computational resources. For this purpose, an optimization problem that models the assignment of resources at these two levels is formulated. A decomposition model is adopted to solve the problem by formulating two binary integer programming subproblems; one for each level. Furthermore, two low complexity heuristic algorithms are developed to solve each subproblem. Results show that the computational resource requirements and the power consumption of BBUs and the physical machines decrease as the channel quality worsens. Moreover, the developed heuristic solution achieves a close to optimal performance while having a lower complexity. Finally, both models achieve high resource utilization, cementing the efficiency of the proposed solutions.
Autors: Emad Aqeeli;Abdallah Moubayed;Abdallah Shami;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 1311 - 1322
Publisher: IEEE
 

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