Electrical and Electronics Engineering publications abstract of: 03-2017 sorted by title, page: 7

» Double-Digit Growth Highlights a Boom in Robotics [Industrial Activities]
Abstract:
With higher sales and positive forecasts for the coming years, 2015 was another successful year for the robotics industry worldwide. This is confirmed by rising sales of both industrial and service robots. By 2019, more than 1.4 million new industrial robots will be installed in factories around the world according to the latest forecast from the International Federation of Robotics. Broken down by sector, around 70% of industrial robots are currently used by the automotive, electrical/electronics, and metalworking industries. In 2015, the number of industrial robot installations in the electronics industry showed the strongest growth, with an increase of 18% (metalworking industry 16%, automotive sector 10%). In a global comparison, the countries of the European Union are especially highly developed in automation in general.
Autors: Martin Hagele;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Mar 2017, volume: 24, issue:1, pages: 12 - 14
Publisher: IEEE
 
» Downlink MU-MIMO With THP Combined With Pre- and Post-processing and Selection of the Processing Vectors for Maximization of Per-Stream SNR
Abstract:
In this paper, we consider a downlink multiuser multiple-input–multiple-output (MU-MIMO) system with multiple antennas at the transmitter and multiple antennas at each user, where the transmitter can send one or more data streams to each user. We propose a non-iterative method by combining Tomlinson–Harashima precoding (THP) with pre- and post-processing and selecting processing vectors based on the maximization of instantaneous signal-to-noise ratio (SNR) of the data stream at the input of the detector of each user. The postprocessing vectors for all users are found to be eigenvectors corresponding to the maximum eigenvalue of a certain matrix involving the channel matrix of the user. The transmitter computes the vectors of the linear processing matrix through an orthonormalization procedure in a single step. The feedback matrix at the transmitter is then obtained from the effective channel matrix and the linear processing matrix. We express the instantaneous SNR of all data streams in terms of eigenvalues of a Wishart matrix, obtained from the channel matrix of the user, and find the diversity order for each data stream. Considering multiple scenarios, we find the outage probability of the instantaneous SNR for all data streams and the cumulative distribution function (cdf) of the sum-rate capacity for all users using the proposed method and compare the results with those of recently proposed methods that provide a closed-form solution and with that of block diagonalization, channel inversion, and THP in scenarios where they are applicable.
Autors: Nanda Kishore Chavali;Kiran Kuchi;V. Umapathi Reddy;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2223 - 2236
Publisher: IEEE
 
» Downscaling Metal—Oxide Thin-Film Transistors to Sub-50 nm in an Exquisite Film-Profile Engineering Approach
Abstract:
We report an exquisite, film-profile-engineering approach for producing nanometer-scale channel-length (L) ZnO thin-film transistors (TFTs). The scheme is based on a unique laminated structure in conjunction with a well-designed etching process for building a slender, suspending bridge that shadows the subsequent deposition of pivotal thin films of ZnO and gate oxide as well as simultaneously defines L of the TFTs. With the approach, we have ingeniously downscaled L of ZnO TFTs to as short as 10 nm. The experimental ZnO TFTs of L = 50 and 30 nm, respectively, exhibit excellent performance in terms of high on/off current ratio of and , superior subthreshold swing of 92 and 95 mV/decade, and small drain induced barrier lowering of 0.1 and 0.29 V/V. Remarkably the nanometer-scale ZnO TFTs possess excellent device uniformity. Furthermore, the precise control over the geometrical sizes for the channel length enables the fabrication of ultrashort ZnO TFTs of L as short as 10 nm with reasonable gate transfer characteristics.
Autors: Rong-Jhe Lyu;Bo-Shiuan Shie;Horng-Chih Lin;Pei-Wen Li;Tiao-Yuan Huang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1069 - 1075
Publisher: IEEE
 
» DRAM-Based Intrinsic Physically Unclonable Functions for System-Level Security and Authentication
Abstract:
A physically unclonable function (PUF) is an irreversible probabilistic function that produces a random bit string. It is simple to implement but hard to predict and emulate. PUFs have been widely proposed as security primitives to provide device identification and authentication. In this paper, we propose a novel dynamic-memory-based PUF [dynamic RAM PUF (DRAM PUF)] for the authentication of electronic hardware systems. The DRAM PUF relies on the fact that the capacitor in the DRAM initializes to random values at startup time. Most PUF designs require custom circuits to convert unique analog characteristics into digital bits, but using our method, no extra circuitry is required to achieve a reliable 128-bit PUF. The results show that the proposed DRAM PUF provides a large number of input patterns (challenges) compared with other memory-based PUF circuits such as static RAM PUFs. Our DRAM PUFs provide highly unique PUFs with a 0.4937 average interdie Hamming distance. We also propose an enrollment algorithm to achieve highly reliable results to generate PUF identifications for system-level security. This algorithm has been validated on real DRAMs with an experimental setup to test different operating conditions.
Autors: Fatemeh Tehranipoor;Nima Karimian;Wei Yan;John A. Chandy;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 1085 - 1097
Publisher: IEEE
 
» Drifts and Environmental Disturbances in Atomic Clock Subsystems: Quantifying Local Oscillator, Control Loop, and Ion Resonance Interactions
Abstract:
Linear ion trap frequency standards are among the most stable continuously operating frequency references and clocks. Depending on the application, they have been operated with a variety of local oscillators (LOs), including quartz ultrastable oscillators, hydrogen-masers, and cryogenic sapphire oscillators. The short-, intermediate-, and long-term stability of the frequency output is a complicated function of the fundamental performances, the time dependence of environmental disturbances, the atomic interrogation algorithm, the implemented control loop, and the environmental sensitivity of the LO and the atomic system components. For applications that require moving these references out of controlled lab spaces and into less stable environments, such as fieldwork or spaceflight, a deeper understanding is needed of how disturbances at different timescales impact the various subsystems of the clock and ultimately the output stability. In this paper, we analyze which perturbations have an impact and to what degree. We also report on a computational model of a control loop, which keeps the microwave source locked to the ion resonance. This model is shown to agree with laboratory measurements of how well the feedback removes various disturbances and also with a useful analytic approach we developed for predicting these impacts.
Autors: Daphna G. Enzer;William A. Diener;David W. Murphy;Shanti R. Rao;Robert L. Tjoelker;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Mar 2017, volume: 64, issue:3, pages: 623 - 633
Publisher: IEEE
 
» Driving Cycle Equivalence and Transformation
Abstract:
There is a strong trend to use driving cycles extensively in vehicle design, particularly for the calibration and tuning of all powertrain systems for control and diagnosis. In such situations, it is essential to capture real driving; therefore, using only a few driving cycles would lead to the risk that a test or a design is tailored to a specific driving cycle. Consequently, there are now widespread activities using techniques from statistics, big data, and mission modeling to address these issues. For all such methods, there is an important final step to calibrate a representative cycle to adhere to fair propulsion requirements on the driven wheels over a cycle. For this, a general methodology has been developed, which is applicable to a wide range of problems involving driving cycle transformations. It is based on a definition of equivalence for driving cycles of, loosely speaking, being similar without being the same. Based on this definition, a set of algorithms is developed to transform a given driving cycle into an equivalent driving cycle or into a cycle with a given equivalence measure. The transformations are effectively handled as a nonlinear program that is solved by using general-purpose optimization techniques. The proposed method is general, and a wide range of constraints can be used.
Autors: Peter Nyberg;Erik Frisk;Lars Nielsen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 1963 - 1974
Publisher: IEEE
 
» Drones Ripe for Pervasive Use
Abstract:
Initial drone research was mostly concerned with improving technical abilities--including battery power and flight accuracy. More recent research investigates how drones can support existing application domains and even create new ones. This special issue looks at some of this more recent research. Instead of looking at the larger drones mostly used during military operations, it focuses on smaller drones, which fly at lower altitudes and thus could play a more significant role in pervasive computing applications.
Autors: Florian Floyd Mueller;Albrecht Schmidt;
Appeared in: IEEE Pervasive Computing
Publication date: Mar 2017, volume: 16, issue:1, pages: 21 - 23
Publisher: IEEE
 
» DSP Applications in Engine Control and Onboard Diagnostics: Enabling greener automobiles
Abstract:
Digital signal processing (DSP) has been playing an increasingly important role in engine control and onboard diagnostics (OBD), a critical area of vehicle powertrain controls, to meet increasingly strict fuel efficiency requirements and emission regulations. This article gives an overview of DSP applications in this field from a practical perspective and identifies fruitful areas for DSP research and development in engine control and OBD. It also provides examples in the areas of engine misfire detection, individual cylinder fuel-air ratio imbalance detection, and engine knock detection.
Autors: Zhijian James Wu;Sanjeev M. Naik;
Appeared in: IEEE Signal Processing Magazine
Publication date: Mar 2017, volume: 34, issue:2, pages: 70 - 81
Publisher: IEEE
 
» Dual Frequency Millimeter-Wave Illumination of a Detector Diode
Abstract:
In this letter, a GaAs beam lead diode is illuminated by two fixed W-band millimeter-wave frequencies to assess the difference frequency response at the X-band. Measured results are compared with an expected mixed frequency response, utilizing a Volterra series expansion solution, which considers the reactive component influences under nonconjugate matching conditions. A nonlinear model is assessed with the solution approach to predict potential performance. A nonconjugate matched condition provides good agreement with less than 2-dB variation across the central slice of the response.
Autors: Robert A. Smith;Zahra A. Pour;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 308 - 310
Publisher: IEEE
 
» Dual-Band and Dual-Circularly Polarized Single-Layer Microstrip Array Based on Multiresonant Modes
Abstract:
A planar dual-band array with orthogonal circular polarizations (CPs) in the two frequency bands is proposed in this communication. The array is implemented on a single-layer substrate and easy to be extended to the design of a larger array. A new antenna element for such an array is exploited by symmetrically loading stubs on the edges of a square patch. In this communication, two pairs of orthogonal modes of the patch, namely, TM10/TM01 and TM30/TM03, are excited simultaneously and used to realize different senses of CP radiation in the two bands. An equivalent transmission-line model of this patch is then developed to describe its working principle and design procedure. To validate its effectiveness, a -element array prototype operating at 2.53 and 3.59 GHz is designed and fabricated. Both the left- and right-hand CPs are obtained simultaneously in the dual bands, and the measured results are found to be in good agreement with the simulated ones. The measured radiation gains in the lower and higher bands are 10.8 and 12.5 dBic, respectively.
Autors: Jin-Dong Zhang;Lei Zhu;Neng-Wu Liu;Wen Wu;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1428 - 1433
Publisher: IEEE
 
» Dual-Band Electronically Beam-Switched Antenna Using Slot Active Frequency Selective Surface
Abstract:
This communication presents an a cylindrical active frequency selective surface (AFSS)-based electronically beam-switching antenna, which can operate at two different frequency bands. The antenna consists of a slot AFSS and an omnidirectional dual-band feed antenna. The p-i-n diodes of the AFSS can be switched on or off to reconfigure the AFSS as transparent or opaque to the incident electromagnetic waves, respectively. Thus, by controlling the dc bias voltages to different columns of p-i-n diodes, the directive beams of the antenna can be swept to cover the whole azimuth plane. To validate the design concept, the transmission coefficients of the active FSS sheet are experimentally examined. An antenna prototype operating at 2.5 and 5.3 GHz frequency bands is also fabricated and measured. Simulation and measurement results of the antenna are presented to verify the design principle. A comparison between this communication and other recent designs is provided. The antenna has advantages of low power, low cost, easy fabrication, and electronic beam switching covering a full 360° angular range.
Autors: Chao Gu;Benito Sanz Izquierdo;Steven Gao;John C. Batchelor;Edward A. Parker;Fan Qin;Gao Wei;Jianzhou Li;Jiadong Xu;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1393 - 1398
Publisher: IEEE
 
» Dual-Band Half-Elliptic Hoof Antenna With Mathieu Function for a Femto-Cell Network
Abstract:
The design of a half-elliptic hoof antenna for a femto-cell network in a multi-input multioutput system is proposed. The proposed half-elliptic hoof antenna incorporates half-elliptic surfaces, and has multiresonance frequencies in its TM modes. The half-elliptic design of the proposed antenna resonates with two main current paths, and the resonant frequency of each mode can be calculated using the Mathieu function. Moreover, an additional resonator is inserted between the half-elliptic patch and a ground to obtain additional resonance frequency and a wider bandwidth on the high band. The proposed antenna covers the frequency bands from 880 to 960 MHz and from 1710 to 2170 MHz for Global System for Mobile Communications (GSM)/Digital Cellular System (DCS)/Personal Communications Service (PCS)/International Mobile Telecommunications (IMT) with a peak gain of 6.8 dBi. To validate the design of the proposed antenna, the analysis of the antenna using the simulated and measured results is presented and discussed.
Autors: DukSoo Kwon;Seung-Tae Khang;Tae-Dong Yeo;In-June Hwang;Dong-Jin Lee;Jong-Won Yu;Wang-Sang Lee;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1047 - 1054
Publisher: IEEE
 
» Dual-Band Microstrip Bandstop Filter With Multiple Transmission Poles Using Coupled Lines
Abstract:
A novel dual-band microstrip bandstop filter with multiple poles using open/shorted coupled lines is proposed in this paper. Nine transmission poles near the two stopbands can be easily realized by conventional coupled lines and transmission lines. The two center frequencies of the dual-band bandstop filter can be adjusted flexibly by only changing the even/odd-mode of the coupled lines. The planar microstrip dual-band bandstop filter ( and mm) with nine transmission poles is designed and fabricated. High selectivity and good in-band performances can be achieved in the proposed filter.
Autors: Wenjie J. Feng;Meiling L. Hong;Wenquan Q. Che;Quan Xue;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 236 - 238
Publisher: IEEE
 
» Dual-DC-Port Asymmetrical Multilevel Inverters With Reduced Conversion Stages and Enhanced Conversion Efficiency
Abstract:
A new concept of dual-dc-port asymmetrical multilevel inverter (DP-AMI), which is able to interface a low-voltage dc port, a high-voltage dc port, and an ac port simultaneously using only one topology, is presented in this paper. A systematic method to derive the DP-AMI is proposed. With the proposed DP-AMI, a low-voltage dc source, e.g., photovoltaic (PV) modules or battery, can directly supply power to the ac load within single-stage power conversion. Therefore, in comparison with a traditional two-stage dc/ac power conversion system, the power conversion stages are reduced and the voltage/current stress of the front-end dc/dc converter can be significantly alleviated, which can improve the overall conversion efficiency dramatically. Furthermore, by using the low-voltage dc source as a new voltage level, asymmetrical multiple voltage levels are generated by the proposed DP-AMI, which is beneficial for the reducing switching losses and the size/volume of the output filter. The topology derivation method of the DP-AMIs is presented. The operation principles, modulation schemes, and characteristics of one of the proposed DP-AMIs are analyzed in detail. A 1-kW prototype is built and tested to verify the effectiveness and advantages of the proposed method.
Autors: Hongfei Wu;Lei Zhu;Fan Yang;Tiantian Mu;Hongjuan Ge;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2081 - 2091
Publisher: IEEE
 
» Dual-Electrical-Port Control of Cascaded Doubly-Fed Induction Machine for EV/HEV Applications
Abstract:
This paper presents a dual-electrical-port control scheme for four-quadrant operation of cascaded doubly-fed induction machine (CDFIM), which has conventionally been used as a variable-speed drive or variable-speed constant-frequency generator for limited-speed-range applications. The proposed control method enables the synchronous control of both power winding (PW) and control winding (CW) currents, and as a consequence, not only the control complexity but also the rotor slip frequency and related core losses are significantly reduced in comparison with the previously proposed single-electrical-port control scheme. It is for the first time revealed that the CDFIM drive that indirectly couples PW and CW through induction behavior can be readily controlled like a conventional induction motor to achieve the highest torque density. The torque density–speed region of the CDFIM falls within that of the power machine in singly-fed operation mode, and only a half of that of the power machine in doubly-fed operation mode, which shows the urgent need for torque density enhancement of brushless doubly-fed machines for electric vehicle/hybrid electric vehicle applications. Computer simulations and experiments are implemented to verify the dynamic performance of the proposed control method.
Autors: Peng Han;Ming Cheng;Zhe Chen;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1390 - 1398
Publisher: IEEE
 
» Dual-Mode All-Digital Baseband Receiver With a Feed-Forward and Shared-Memory Architecture for Dual-Standard Over 60 GHz NLOS Channel
Abstract:
In this paper, an 8X-parallelism all-digital baseband receiver is proposed to support SC and OFDM modes for both IEEE 802.15.3c and IEEE 802.11ad standards. The all-digital baseband receiver contains a 4-in-1 synchronization (SYNC), a 512-point radix-23 IFFT/FFT, a phase noise cancellation (PNC), a shared memory (MEM) bank and a frequency-domain equalizer (FDE) with an optimized golay-correlator window-based noise cancellation (OGC-WNC) channel estimation (CE) for non-line-of-sight (NLOS) and line-of-sight (LOS) channels. The hardware sharing is 99% between SC and OFDM modes and the shared memory reduces memory usage by 51%. The measurement results show that the fabricated chip can provide PHY data rate of 9.24 Gb/s with power consumption of 497 mW to meet the requirement of OFDM mode for IEEE 802.15.3c and 802.11ad standards. Besides, the PHY data rate of the fabricated chip reaches 14 Gb/s with power consumption of 698 mW for OFDM mode that is beyond the standard requirement to offer higher PHY data rate over 60 GHz transmission environment.
Autors: Chun-Yi Liu;Meng-Siou Sie;Edmund Wen Jen Leong;Yu-Cheng Yao;Chih-Wei Jen;Wei-Chang Liu;Chih-Feng Wu;Shyh-Jye Jou;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 608 - 618
Publisher: IEEE
 
» Dual-Mode Substrate Integrated Waveguide Filter With Flexible Response
Abstract:
This paper proposes a novel dual-mode substrate integrated waveguide (SIW) filter technique. Based on the conventional dual-mode SIW structure, further investigation is performed. Multiple transmission zeros can be obtained at one side or both sides of the passband for an SIW cavity. Therefore, flexible design and high performance response can be available for dual-mode SIW filter. A dual-mode SIW bandpass filter with quasi-elliptic response and a dual-mode SIW diplexer with asymmetric channel response are simulated, fabricated, and measured to demonstrate and verify the novel property.
Autors: Peng Chu;Wei Hong;Mingguang Tuo;Kai-Lai Zheng;Wen-Wen Yang;Feng Xu;Ke Wu;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Mar 2017, volume: 65, issue:3, pages: 824 - 830
Publisher: IEEE
 
» Dual-Polarized Spatial Modulation Over Correlated Fading Channels
Abstract:
We address multiple-input multiple-output (MIMO) communication employing spatial modulation (SM) with dual-polarized (DP) antennas. The proposed architecture adds the polarization dimension to the conventional SM mappings and offers performances, which are comparable to or under certain conditions even better than those of the uni-polarized systems while occupying half as much space. We consider the generalized spatially correlated Rayleigh and Rician fading channel models and present an average bit-error probability upper bounding framework for the proposed DP SM-MIMO system. The theoretical error analysis is also extended to the case where the channel coefficients are estimated with Gaussian estimation errors. This upper bounding method is also used to determine the conditions in which the dual-polarized SM is better than equivalent systems with uni-polarized antennas. Theoretical derivations are also validated by extensive simulations, both corroborating that SM combined with dual-polarization forms an attractive alternative not only for its improved multiplexing gains and space efficiency but also for performance gains over correlated channels.
Autors: Golara Zafari;Mutlu Koca;Hikmet Sari;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 1336 - 1352
Publisher: IEEE
 
» Dunking the data center
Abstract:
When Sean James, who works on data-center technology for Microsoft, suggested that the company put server farms entirely underwater, his colleagues were a bit dubious. But for James, who had earlier served on board a submarine for the U.S. Navy, submerging whole data centers beneath the waves made perfect sense. . This tactic, he argued, would not only limit the cost of cooling the machines-an enormous expense for many data-center operators-but it could also reduce construction costs, make it easier to power these facilities with renewable energy, and even improve their performance.
Autors: Ben Cutler;Spencer Fowers;Jeffrey Kramer;Eric Peterson;
Appeared in: IEEE Spectrum
Publication date: Mar 2017, volume: 54, issue:3, pages: 26 - 31
Publisher: IEEE
 
» Dynamic Analysis of a Novel Single-Phase Induction Generator Using an Improved Machine Model
Abstract:
The dynamic analysis using an improved transient model of a recently introduced single-phase induction generator suitable for renewable energy conversion is presented in this paper. In this three-phase cage type induction machine based generator topology, one of the three windings is used as the control winding for real and reactive power control and the other two windings are connected in series to form the output winding. Due to larger percentage errors resulting from existing models in comparison to the experimental values, transient model of the generator is improved to take into account the core loss resistance and the nonlinearity of magnetizing reactance in the saturated region. The generator system is simulated in Matlab software to present a numerical comparison of the simulation results obtained from improved and existing models. The transient behavior of the generator is comprehensively studied by considering sudden variations in rotor speed, excitation control voltage, capacitance and load. The simulation results are verified by experiments performed on a laboratory experimental setup.
Autors: Diana Lamabadu;Sumedha Rajakaruna;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 1 - 11
Publisher: IEEE
 
» Dynamic Analysis of Magnetic Disk Drive Actuators According to Temperature Variation
Abstract:
The initial internal temperature of a hard disk drive (HDD) differs according to the operating environment, and the various heat sources from the surrounding environment raise the internal temperature of the HDD after operation starts. Such temperature change ranges from 0 °C to 60 °C in the usual operating environment. This affects the characteristics of a pivot bearing that supports the HDD actuator. This paper predicts how the characteristics of pivot bearings change in relation to temperature and how the dynamic characteristics of actuators change according to the change of bearing characteristics. These changes are also verified through experiments.
Autors: Young-Jin Kim;Dongho Oh;Gangsik Yun;Moon-Soo Kim;Cheol-Soon Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Mar 2017, volume: 53, issue:3, pages: 1 - 5
Publisher: IEEE
 
» Dynamic Characteristic Analysis of Irreversible Demagnetization in SPM- and IPM-Type BLDC Motors
Abstract:
In this study, the dynamic characteristic analysis algorithm is developed for the irreversible demagnetization. The conventional static characteristic analysis of irreversible demagnetization considers only the d-axis magnetic flux components. However, the accuracy of this method is limited in its analysis of the characteristics of the irreversible demagnetization when the motor is rotating. Therefore, we have developed a dynamic characteristic analysis algorithm for irreversible demagnetization. Using the developed algorithm, static and dynamic characteristic analysis of irreversible demagnetization is compared for interior- and surface-type permanent magnets brushless dc motor. Finally, we propose a maximum current limit for motor designs to reduce the impact of irreversible demagnetization.
Autors: Hyung-Kyu Kim;Jin Hur;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 982 - 990
Publisher: IEEE
 
» Dynamic Computation Offloading for Low-Power Wearable Health Monitoring Systems
Abstract:
Objective: The objective of this paper is to describe and evaluate an algorithm to reduce power usage and increase battery lifetime for wearable health-monitoring devices. Methods: We describe a novel dynamic computation offloading scheme for real-time wearable health monitoring devices that adjusts the partitioning of data processing between the wearable device and mobile application as a function of desired classification accuracy. Results: By making the correct offloading decision based on current system parameters, we show that we are able to reduce system power by as much as 20%. Conclusion: We demonstrate that computation offloading can be applied to real-time monitoring systems, and yields significant power savings. Significance: Making correct offloading decisions for health monitoring devices can extend battery life and improve adherence.
Autors: Haik Kalantarian;Costas Sideris;Bobak Mortazavi;Nabil Alshurafa;Majid Sarrafzadeh;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Mar 2017, volume: 64, issue:3, pages: 621 - 628
Publisher: IEEE
 
» Dynamic Equivalents by Modal Decomposition of Tie-Line Active Power Flows
Abstract:
This paper addresses the power system model order reduction proposing an optimal formulation for identifying electromechanical modes present in active power flows. The reduced power system preserves the dynamic and physical characteristics of the studied system. The modal identification is achieved by the digital Taylor–Fourier transform, which decomposes an oscillating signal into monocomponents. Then, these ones are embedded into an objective function with the purpose of estimating the equivalent generators’ parameters. Results demonstrate a reduction in the computational burden and the computing time associated with transient stability studies for the preserved system, retaining its steady-state and dynamic conditions.
Autors: Mario R. Arrieta Paternina;Juan M. Ramirez-Arredondo;José David Lara-Jiménez;Alejandro Zamora-Mendez;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1304 - 1314
Publisher: IEEE
 
» Dynamic Modeling and Analysis of Constant On Time Variable Frequency One-Cycle Control for Switched-Capacitor Converters
Abstract:
A constant on time variable frequency one-cycle control technique (CVFOCC) for switched-capacitor (SC) converters is presented in this paper. It is designed to accomplish the continuous variable conversion ratio and fast dynamical response to reject the external disturbance. A proper regulation can be obtained by controlling the related “off time” of a transistor with the constant “on time” which is less than the time constant of the charge loop. A unique large-signal dynamic capacitor ampere-second balance (CASB) model for SC converters is applied in this research study. It is implemented to instantaneously estimate transient values of the equivalent circuits. The proposed modeling method and analysis have been verified by comparing the modeling expressions with simulation and experiment results for different input voltages, load currents and switching frequencies. The simulation and experiment results show that the external disturbance of a single-stage SC converter could be immediately rejected by the proposed control method. The good line and load regulation are demonstrated. The proposed control method is stable and global. It can work in a wide operation range with a simple control circuit for general SC converters.
Autors: Lei Yang;Bin Wu;Xiaobin Zhang;Keyue Smedley;Guann-Pyng Li;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 630 - 641
Publisher: IEEE
 
» Dynamic Performance Improvement of a Grid-Tied PV System Using a Feed-Forward Control Loop Acting on the NPC Inverter Currents
Abstract:
This paper presents a three-phase grid-connected photovoltaic (PV) system, which is implemented using the neutral-point-clamped (NPC) inverter. A current feed-forward control loop (FFCL) is proposed to improve the PV system dynamic behavior, due to the PV array being constantly subjected to sudden solar irradiance change, which causes voltage oscillations in the dc bus and, hence, interferes in proper PV system operation. As the current FFCL acts to speed up the calculation of the inverter current references, the dynamic response of the currents injected into the grid is improved. As a consequence, the dynamic behavior of the dc-bus voltage is also enhanced, reducing both settling time and overshoot. Besides the injection of active power into the grid, the PV system is also controlled to perform active power-line conditioning, so that load harmonic currents are suppressed, as well as load reactive power is compensated. However, the NPC inverter must be properly designed to guarantee that its power rating will not be exceeded, since both fundamental and nonfundamental current components flow through the grid-tied inverter. Extensive experimental results based on a digital signal processor are presented in order to evaluate the effectiveness, as well as the static and dynamic performance of the PV system.
Autors: Leonardo Bruno Garcia Campanhol;Sérgio Augusto Oliveira da Silva;Azauri Albano de Oliveira;Vinícius Dário Bacon;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2092 - 2101
Publisher: IEEE
 
» Dynamic Projection Mapping onto Deforming Non-Rigid Surface Using Deformable Dot Cluster Marker
Abstract:
Dynamic projection mapping for moving objects has attracted much attention in recent years. However, conventional approaches have faced some issues, such as the target objects being limited to rigid objects, and the limited moving speed of the targets. In this paper, we focus on dynamic projection mapping onto rapidly deforming non-rigid surfaces with a speed sufficiently high that a human does not perceive any misalignment between the target object and the projected images. In order to achieve such projection mapping, we need a high-speed technique for tracking non-rigid surfaces, which is still a challenging problem in the field of computer vision. We propose the Deformable Dot Cluster Marker (DDCM), a novel fiducial marker for high-speed tracking of non-rigid surfaces using a high-frame-rate camera. The DDCM has three performance advantages. First, it can be detected even when it is strongly deformed. Second, it realizes robust tracking even in the presence of external and self occlusions. Third, it allows millisecond-order computational speed. Using DDCM and a high-speed projector, we realized dynamic projection mapping onto a deformed sheet of paper and a T-shirt with a speed sufficiently high that the projected images appeared to be printed on the objects.
Autors: Gaku Narita;Yoshihiro Watanabe;Masatoshi Ishikawa;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Mar 2017, volume: 23, issue:3, pages: 1235 - 1248
Publisher: IEEE
 
» Dynamic State Estimation Based Control Strategy for DFIG Wind Turbine Connected to Complex Power Systems
Abstract:
This paper proposes a viable solution to the long-lasting issue of using flux-involved control scheme to regulate the behavior of doubly fed induction generator (DFIG) during faults. Instead of trying to design a complicated method to measure flux, which cannot be directly measured with contemporary technology, the solution utilizes unscented Kalman filter-based dynamic state estimation of DFIG connected to a complex power system to estimate the wanted variables. The decentralized estimation scheme takes into consideration the overall power system network and uses only local noisy PMU measurement data. DFIG control schemes are also investigated to a fair extent where three control methods are discussed with comparison results presented. The improved control scheme displays a better fault recovery response and system compatibility. A number of considerations are taken into account in the design of DFIG control schemes, including reactive power supports and dc-link current compensation.
Autors: Shenglong Yu;Tyrone Fernando;Kianoush Emami;Herbert Ho-Ching Iu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1272 - 1281
Publisher: IEEE
 
» Dynamically Reconfigurable Independent Cellular Switching Circuits for Managing Battery Modules
Abstract:
In battery packs, batteries need to be serially connected to obtain high voltage, connected in parallel to acquire high current, and the defected batteries need to be bypassed. In this study, dynamically reconfigurable, independent cellular switching circuits have been proposed in order to connect the batteries in desired configuration. Each cell comprises a battery, a serial switch, a bypass switch, a parallel switch, and triggering switches. The batteries within the pack can be connected in different configurations according to their operation mode such as all in serial, all in parallel, all bypassed, or hybrid (serial–parallel–bypass). The novel aspect of the proposed circuit is that only intracellular battery energy is utilized in order to trigger the switches that are controlled with a very simple circuit. Each cell is independent and completely modular. Moreover, a single mosfet is sufficient instead of two mosfets which is connected in serial in order to control the current. The complexity of the circuit has been reduced to three mosfets for each cell and its efficiency has been increased. The operation of the proposed circuit has been tested with a prototype that includes twelve batteries and its advantages have been confirmed.
Autors: Goksel Gunlu;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 194 - 201
Publisher: IEEE
 
» E-HIPA: An Energy-Efficient Framework for High-Precision Multi-Target-Adaptive Device-Free Localization
Abstract:
Device-free localization (DFL), which does not require any devices to be attached to target(s), has become an appealing technology for many applications, such as intrusion detection and elderly monitoring. To achieve high localization accuracy, most recent DFL methods rely on collecting a large number of received signal strength (RSS) changes distorted by target(s). Consequently, the incurred high energy consumption renders them infeasible for resource-constraint networks, such as wireless sensor networks. This paper introduces an e nergy-efficient framework for high-precision multi-target-a daptive device-free localization (E-HIPA). Compared with the existing methods, E-HIPA demands fewer transceivers, applies the compressive sensing (CS) theory to guarantee high localization accuracy with less RSS change measurements. The motivation behind the proposed E-HIPA is the sparse nature of multi-target locations in the spatial domain. Before taking advantage of this intrinsic sparseness, we theoretically prove the validity of the proposed CS-based framework problem formulation. Based on the formulation, the proposed E-HIPA primarily includes an adaptive orthogonal matching pursuit (AOMP) algorithm, by which it is capable of recovering the precise location vector with high probability, even for a more practical scenario with unknown target number. Experimental results via real testbed demonstrate that, compared with the previous state-of-the-art solutions, i.e., RTI, SCPL, and RASS approaches, E-HIPA reduces the energy consumption by up to 69 percent with meter-level localization accuracy.
Autors: Ju Wang;Dingyi Fang;Zhe Yang;Hongbo Jiang;Xiaojiang Chen;Tianzhang Xing;Lin Cai;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Mar 2017, volume: 16, issue:3, pages: 716 - 729
Publisher: IEEE
 
» ECG Signal Analysis Using DCT-Based DOST and PSO Optimized SVM
Abstract:
Signal processing techniques are an obvious choice for real-time analysis of electrocardiography (ECG) signals. However, classical signal processing techniques are unable to deal with the nonstationary nature of the ECG signal. In this context, this paper presents a new approach, i.e., discrete orthogonal stockwell transform using discrete cosine transform for efficient representation of the ECG signal in time–frequency space. These time–frequency features are further reduced in lower dimensional space using principal component analysis, representing the morphological characteristics of the ECG signal. In addition, the dynamic features (i.e., RR-interval information) are computed and concatenated to the morphological features to constitute the final feature set, which is utilized to classify the ECG signals using support vector machine (SVM). In order to improve the classification performance, particle swarm optimization technique is employed for gradually tuning the learning parameters of the SVM classifier. In this paper, ECG data exhibiting 16 classes of the most frequently occurring arrhythmic events are taken from the benchmark MIT-BIH arrhythmia database for the validation of the proposed methodology. The experimental results yielded an improved overall accuracy, sensitivity (Sp), and positive predictivity (Pp) of 98.82% in comparison with the existing approaches available in the literature.
Autors: Sandeep Raj;Kailash Chandra Ray;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 470 - 478
Publisher: IEEE
 
» Echo State Network for Fast Channel Prediction in Ricean Fading Scenarios
Abstract:
A fast channel prediction scheme is proposed for Ricean fading scenarios. By employing an echo state network (ESN), the scheme is able to obtain smaller prediction error than previous designs. Simulation results show that the ESN prediction method has lower normalized mean squared error than the traditional autoregressive, discrete wavelet transform, and support vector machine prediction approaches. The symbol error rate gap between the perfect and predicted channel state information is small.
Autors: Yisheng Zhao;Hui Gao;Norman C. Beaulieu;Zhonghui Chen;Hong Ji;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 672 - 675
Publisher: IEEE
 
» EcoTrec—A Novel VANET-Based Approach to Reducing Vehicle Emissions
Abstract:
There are interdependent increases in vehicle numbers, vehicular traffic congestion, and carbon emissions that cause major problems worldwide. These problems include direct negative influences on people's health, adverse economic effects, negative social impacts, local environmental damage, and risk of catastrophic global climate change. There is a drastic need to develop ways to reduce these emissions and EcoTrec, presented in this paper, is one of these innovative approaches. EcoTrec is a vehicular ad hoc network-based vehicle routing solution designed to reduce vehicle carbon emissions without significantly affecting the travel times of vehicles. The vehicles exchange messages related to traffic and road conditions, such as average speed on the road, road gradient, and surface condition. This information is used to build a fuel efficiency model of the routes, based on which the vehicles are recommended to take more efficient routes. By routing vehicles more efficiently, the greenhouse emissions are reduced while also maintaining low traffic congestion levels. This paper presents results of extensive simulations, which show how EcoTrec outperforms other state-of-the-art solutions with different number of vehicles, vehicle penetration, and compliance rates, and when considering different real world road maps from Dublin and Koln.
Autors: Ronan Doolan;Gabriel-Miro Muntean;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Mar 2017, volume: 18, issue:3, pages: 608 - 620
Publisher: IEEE
 
» Edge and Cloud Pricing for the Sharing Economy
Abstract:
Edge devices and cloud services form crucial parts of the Internet of Things technology stack, where both are integrated into smart cities' ecosystems. However, while the latter usually include pricing plans in their offerings, the former generally don't consider economic aspects of their cooperation. In this article, the authors introduce a framework that leverages pricing aspects as first-class citizens, enabling the sharing economy vision for edge devices applied to the smart city scenario.
Autors: José María García;Pablo Fernández;Antonio Ruiz-Cortés;Schahram Dustdar;Miguel Toro;
Appeared in: IEEE Internet Computing
Publication date: Mar 2017, volume: 21, issue:2, pages: 78 - 84
Publisher: IEEE
 
» Edge Coloring and Stopping Sets Analysis in Product Codes With MDS Components
Abstract:
We consider non-binary product codes with MDS components and their iterative row-column algebraic decoding on the erasure channel. Both independent and block erasures are considered in this paper. A compact graph representation is introduced on which we define double-diversity edge colorings via the rootcheck concept. An upper bound of the number of decoding iterations is given as a function of the graph size and the color palette size . Then, we propose a differential evolution edge coloring algorithm that produces colorings with a large population of minimal rootcheck order symbols. The complexity of this algorithm per iteration is , for a given differential evolution parameter , where itself is small with respect to the huge cardinality of the coloring ensemble. Stopping sets of a product code are defined in the context of MDS components and a relationship is established with the graph representation. A full characterization of these stopping sets is given up to a size , where is the minimum Hamming distance of the MDS component code. The performance of MDS-based product codes with and without double-diversity coloring is analyzed in presence of both the block and the independent erasures. In the latter case, ML and iterative decoding are proven to coincide at small channel erasure probability. Furthermore, numerical results show excellent performance in presence of unequal erasure probability due to double-diversity colorings.
Autors: Fanny Jardel;Joseph Jean Boutros;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1439 - 1462
Publisher: IEEE
 
» Editor's Note
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Leila De Floriani;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Mar 2017, volume: 23, issue:3, pages: 1163 - 1164
Publisher: IEEE
 
» Editorial
Abstract:
Writing is a part of our profession, and many of us are not only writers but also editors. I use the term "editors" for educators or researchers for whom editing others' work has become common practice. We are not professional editors per se who have established careers in the skill, such as editors for magazines and newspapers, but as supervisors and committee members, we do in fact edit works such as research proposals, papers, theses, and reports in addition to reviewing. What I would like to share here with readers is how to help reduce some of the editorial burden. I am not trying to correct anyone's writing; I wish to simply raise concern about the misuse of units, notations, and significant figures in measurement and reporting and improper citations. Although style and form are taught in schools and colleges, accompanied by standards that outline guidelines, mistakes are often ignored or even overlooked.
Autors: Shesha Jayaram;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Mar 2017, volume: 33, issue:2, pages: 4 - 5
Publisher: IEEE
 
» Editorial Control Systems and the Quest for Autonomy
Abstract:
Autors: P. Antsaklis;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1013 - 1016
Publisher: IEEE
 
» Editorial Special Section on Multiscale Cancer Modeling
Abstract:
The papers in this special section focus on the use of multiscale modeling in the field of cancer research. Cancer is a complex, heterogeneous disease, characterized by many interaction processes on, and across, multiple scales in time and space that act in concert to drive cancer formation, progression, invasion, and metastasis. These processes range from molecular reactions to cell-cell interactions, to tumor growth and invasion on the tissue-scale, and even to larger scales, such as the physiology, pathophysiology, and population scales. In addition, many cancer properties (including, e.g., size, cell density, extracellular ligands, cellular receptors, mutation type(s), phenotypic distribution, vasculature status, blood vessel permeability, and treatment prognosis) are dynamic and patient-dependent, changing and evolving with both time and treatments. For example, cell death rate may change over time due to chemotherapy. All these dynamically changing cancer properties make development of effective cancer therapies extremely difficult. Computational modeling has the potential to predict complex behaviors of cancer, elucidate regulatory mechanisms, and help inform experimental design. Everyone would agree that computer simulations are usually more cost-effective, efficient, and tractable, relative to laboratory experiments.
Autors: Z. Wang;P. K. Maini;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Mar 2017, volume: 64, issue:3, pages: 501 - 503
Publisher: IEEE
 
» Editorial to the regular issue
Abstract:
This is the 3st issue of the IEEE Latin America Transactions of the year 2017. Volume 15 Issue 3, March 2017
Autors: Mirela Sechi Moretti Annoni Notare;
Appeared in: IEEE Latin America Transactions
Publication date: Mar 2017, volume: 15, issue:3, pages: 383 - 392
Publisher: IEEE
 
» Editorial Year-in-Review
Abstract:
The Editorial Board of IEEE Electron Device Letters strives to make our journal the preferred venue for researchers to rapidly publish their original and most significant contributions to the field of integrated-circuit (IC) devices and technology. We rely on a large number of volunteer expert reviewers to evaluate submitted manuscripts and provide constructive feedback to the authors in a timely manner, to maintain the high quality of the manuscript review process.
Autors: Tsu-Jae King Liu;
Appeared in: IEEE Electron Device Letters
Publication date: Mar 2017, volume: 38, issue:3, pages: 297 - 297
Publisher: IEEE
 
» Editorial: A Message from the Editorial Team and an Introduction to the January-March 2017 Issue
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Peter Brusilovsky;Mike Sharples;
Appeared in: IEEE Transactions on Learning Technologies
Publication date: Mar 2017, volume: 10, issue:1, pages: 1 - 2
Publisher: IEEE
 
» Editorial: Special Section on Harnessing Flexible Transmission Assets for Power System Optimization
Abstract:
The role of power flow control is increasing in importance due to variable resources and the difficulty of siting new transmission. While HVDC, flexible AC transmission systems, and transmission switching are utilized today, their capabilities have been incorporated into existing operations decision support tools, such as energy management systems, only to a very limited extent. As a result, such flexible transmission assets are underutilized. This special section of the IEEE Transactions on Power Systems is focused on software development, modeling, and algorithms that address practical challenges on real-world test cases in order to achieve near-term industry adoption.
Autors: Kory W. Hedman;Patrick Panciatici;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1595 - 1596
Publisher: IEEE
 
» Effect of Different Carbon Doping Techniques on the Dynamic Properties of GaN-on-Si Buffers
Abstract:
The effect of different carbon doping techniques on the dynamic behavior of GaN-on-Si buffer was investigated. Intentional doping using a hydrocarbon precursor was compared with the more common autodoping technique. Breakdown and dynamic behavior of processed devices indicate that extrinsic carbon doping delivers better dynamic properties for the same blocking voltage capabilities. Modeling and simulations have revealed that charge transport across the GaN buffer is the main limiting factor during the buffer discharge process.
Autors: H. Yacoub;C. Mauder;S. Leone;M. Eickelkamp;D. Fahle;M. Heuken;H. Kalisch;A. Vescan;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 991 - 997
Publisher: IEEE
 
» Effect of Microstructure and Anisotropy of Copper on Reliability in Nanoscale Interconnects
Abstract:
The mechanical behavior of copper is highly anisotropic. Although it is a face centered cubic crystal, the elastic constants vary considerably for different crystallographic orientations. Typically, the copper metal conductor lines in integrated circuits are polycrystalline in nature. In this paper, we utilize Voronoi tessellation to model the polycrystalline microstructure for the copper metal lines in test structures and then assign textured orientation to each grain and assign corresponding anisotropic elastic constants based on the assigned orientation. By subjecting the test structure through a thermal stress, we observe over 10x variation in normal stresses along the grain boundaries depending on the orientation, dimensions, surroundings, and location of the grains. This may introduce new weak points within the metal interconnects where normal stresses can be very high depending on the orientation of the grains leading to delamination and accumulation sites for vacancies. Hence, inclusion of microstructures and corresponding anisotropic properties for copper grains is critical to conduct a realistic study of both stress voiding and electromigration phenomena, especially at smaller nodes where the anisotropic effects are significant. Further, a comparison between stress levels in test structures with SiCOH and SiO2 as the inter level dielectric was conducted.
Autors: Adarsh Basavalingappa;James R. Lloyd;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 69 - 79
Publisher: IEEE
 
» Effect of Power Control on Performance of Users in an Interference-Limited Network With Unsaturated Traffic
Abstract:
As the base of quality-of-service (QoS) guarantee and system optimizing, performance analysis is very important for interference-limited networks. The performance of a user is closely related to its service rate. However, in interference-limited networks, the transmissions of users interfere with each other, and the power control and unsaturated traffic make the interference relationship among users more complicated. Hence, the service rates of users are correlated with each other and are difficult to derive. According to the relation between the queue length and the service rate, we propose an - dimensional Markov chain, which models queue states of users, to study the performance of an interference-limited system. By calculating the conditional service rate, which is only related to the channel quality given the power policy, the transition matrix is derived. By using the transition matrix, we solve the Markov chain and obtain the stationary probability of the queue length of each user, which enables the calculations of other performance metrics, i.e., delay and packet overflow probability, and so on. Furthermore, to reduce the computational complexity, we decompose the proposed - dimensional Markov chain. Then, based on the decomposition, we propose an iterative algorithm. The comparisons between simulation results and analytical results under different scenarios verify that our method can provide good estimations of each user's performance. The results derived by our method can determine the condition under which the power control algorithm for the saturated system is suitable in unsaturated networks and in which the new power policy is needed.
Autors: Min Sheng;Wanguo Jiao;Xijun Wang;Guoqing Liu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2740 - 2755
Publisher: IEEE
 
» Effect of the Contact Geometry on Nanoscale and Subnanoscale Friction Behaviors
Abstract:
Stick-slip motion is the most well-known phenomenon in nanotribology. Maier et al. previously studied the dependence of slip time on contact geometry. In their paper, they were able to identify the intermediate state during slip motion. However, detailed study of this intermediate state is difficult due to the fast dynamics. The advantage of molecular dynamics (MD) simulation is that it can provide detailed information and direct visualization of the tribological phenomena on a time scale of a few nanoseconds. In this paper, we investigate the detailed mechanism of stick-slip motion in nanoscale. MD simulation precisely mimics friction force microscopy experiments. In MD simulations, a crystalline Si tip slides on a graphene surface, and the tip size is varied. The simulation results provide evidence of the intermediate state during slip motion and reveal the hierarchical structure of the stick-slip motion in nanoscale. Detailed relations among stick-slip motion, contact geometry, and energy state are also analyzed.
Autors: Hong Min Yoon;Joon Sang Lee;
Appeared in: IEEE Transactions on Magnetics
Publication date: Mar 2017, volume: 53, issue:3, pages: 1 - 5
Publisher: IEEE
 
» Effective Capacity of a Novel Spectrum-Band Selection Scheme in Spectrum-Sharing Networks
Abstract:
In this paper, a spectrum-band selection scheme is developed for secondary users (SUs) in underlay spectrum-sharing networks to balance the performance between SUs and primary users (PUs) while guaranteeing PUs' priority. With the developed scheme, among multiple candidate spectrum bands, a given secondary transmitter (ST) is scheduled to access the spectrum band with minimum ratio of the ST–PU channel power gain to the SU link channel power gain. To evaluate this scheme, the SU's performance is investigated concerning its service delay. Under the constraint on average interference from the ST to PUs, the ST's optimal power allocation is obtained in a closed form to achieve the maximum effective capacity (EC) over SU links. Illustrative numerical results and asymptotic discussions substantiate the validity of our derivations and, moreover, demonstrate that, for the case of stringent delay requirements but loose average interference constraint, the band-selection scheme developed in this paper achieves better performance than both the selection of the band with maximum SU link channel power gain and that with minimum ST–PU channel power gain.
Autors: Yuli Yang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2838 - 2843
Publisher: IEEE
 
» Effects Observed in the Characterization of Soft Magnetic Composite for High Frequency, High Flux Density Applications
Abstract:
This paper forms part of a broader study on the design optimization of a high speed switched reluctance motor for automotive traction applications. Due to the high speed operation and resulting high electrical frequency, it is of extreme importance that the different loss components of this motor are accurately calculated. In this study, several effects are observed that influence the accurate measurement of the core loss data used in the calculation of the iron loss in the motor design. It is shown that especially at high frequency and flux density, the loss measurement can be significantly influenced by effects such as temperature, winding AC loss, flux density saturation, and flux waveform shape. The proposed fundamental frequency of the case study motor is 4 kHz, and flux density values of up to 2 T can be obtained under certain load conditions.
Autors: Johannes H. J. Potgieter;Francisco J. Márquez-Fernández;Alexander G. Fraser;Malcolm D. McCulloch;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2486 - 2493
Publisher: IEEE
 
» Effects of a Dyad's Cultural Intelligence on Global Virtual Collaboration
Abstract:
Research problem: The purpose of this study is to examine the effects of the cultural intelligence of a dyad (a team of two persons) on its global virtual collaboration processes and outcomes. Research question: Does a dyad's cultural intelligence have an effect on global virtual collaboration processes and outcomes? If yes, which effects does that cultural intelligence have? Literature review: We review literature on the management of cultural diversity in global virtual collaboration and cultural intelligence. The literature suggests that cultural diversity in global virtual teams is mainly managed with rigid approaches, which are ineffective in many situations. Leveraging cultural intelligence has the potential to improve global virtual collaboration. However, its effects at the team level or in a virtual setting are not yet clear. Methodology: We used a collaboration simulation with 70 participants recruited from two public universities in China and Germany to study the effects of cultural intelligence. Quantitative and qualitative data were collected through questionnaires, voice recorders, and computer logs. Bale's interaction process analysis was used to code the voice recordings, and ordinary least-squares regression was used to test the hypotheses. Results and conclusions: The results indicate that cultural intelligence has an effect on global virtual collaboration; the lower cultural intelligence and the higher cultural intelligence in a dyad exert different effects on global virtual collaboration. Specifically, the lower cultural intelligence significantly influences the frequency of collaborative behaviors, which further influence group satisfaction. In contrast, the higher cultural intelligence significantly influences the deliverable quality. The findings advance the understanding of the effects of cultural intelligence at a dyad level - nd on proximal behavioral outcomes. The study has practical implications for global virtual collaboration practitioners and collaborative virtual environment designers. The study is limited by using student subjects and a self-report measure of cultural intelligence, as well as by examining global virtual teams in their simplest form. Future studies are suggested to examine contingency factors on the relationships between cultural intelligence and global virtual collaboration processes and outcomes.
Autors: Ye Li;Pei-Luen Patrick Rau;Hui Li;Alexander Maedche;
Appeared in: IEEE Transactions on Professional Communication
Publication date: Mar 2017, volume: 60, issue:1, pages: 56 - 75
Publisher: IEEE
 
» Effects of a Hypersonic Plasma Sheath on the Performances of Dipole Antenna and Horn Antenna
Abstract:
This paper discusses the influences of plasma sheath on antennas during hypersonic flights. The practical plasma sheath around an RAM-C vehicle when flying at 25.91 Ma at the altitude of 71 km is evaluated with the fluid analysis method, both dipole antenna and horn antenna are located at the stagnation region and aft body region, respectively, and the antenna performances are compared with those when the plasma sheath does not exist. Numerical results show that when the antennas are located at the stagnation region covered by plasma sheath, for dipole antenna, the gain decreases 7.3 dB and the frequency shifts to higher band by 9.88%, while for the horn antenna, the gain can decrease 4.01 dB and the return loss gets worse. However, when the antennas are located at the aft body region, the antenna performances show hardly any changes no matter the plasma sheath exists or not. The conclusion obtained may provide useful insights for designing antennas on hypersonic vehicles.
Autors: Jie Mei;Yong-Jun Xie;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Mar 2017, volume: 45, issue:3, pages: 364 - 371
Publisher: IEEE
 
» Effects of Arm Swing on Particle Trajectories in HDD Using the CFD Dynamic Mesh Method
Abstract:
Previous works investigated particle trajectories in hard disk drives (HDDs) with the actuator arm and the head gimbals assembly at a fixed position. Actually, internal fluid field characteristics of HDDs can be greatly changed by the arm swing during track-seeking operations, which can affect particle trajectories and trapping status. In this paper, using the dynamic mesh method in a 2.5 in HDD for the first time considers the arm swing in the computational fluid dynamics (CFD) simulation. Al2O3 particle trajectories in this HDD are studied by the CFD solver FLUENT with user-defined functions. The trapping criterion for Al2O3 particles is used as a boundary condition for colliding surfaces. Simulation results reveal that the particle undergoes a larger number of collisions with the disk surface for the average seek time of 12 ms than for the average seek time of 6 ms. In addition, the faster the arm swings, the larger the number of particles that gather near the arm, and the shorter time it will take for particles to be trapped. Moreover, particle-surface collisions can successively take place many times in the helium flow. Furthermore, the particles are trapped slower in the helium-filled drive than in the air-filled drive.
Autors: Guoqing Zhang;Tianqi Zhai;Hui Li;Shengnan Shen;Shijing Wu;Jingshi Zhang;Sheng Liu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Mar 2017, volume: 53, issue:3, pages: 1 - 6
Publisher: IEEE
 
» Effects of Grip-Force, Contact, and Acceleration Feedback on a Teleoperated Pick-and-Place Task
Abstract:
The multifaceted human sense of touch is fundamental to direct manipulation, but technical challenges prevent most teleoperation systems from providing even a single modality of haptic feedback, such as force feedback. This paper postulates that ungrounded grip-force, fingertip-contact-and-pressure, and high-frequency acceleration haptic feedback will improve human performance of a teleoperated pick-and-place task. Thirty subjects used a teleoperation system consisting of a haptic device worn on the subject's right hand, a remote PR2 humanoid robot, and a Vicon motion capture system to move an object to a target location. Each subject completed the pick-and-place task 10 times under each of the eight haptic conditions obtained by turning on and off grip-force feedback, contact feedback, and acceleration feedback. To understand how object stiffness affects the utility of the feedback, half of the subjects completed the task with a flexible plastic cup, and the others used a rigid plastic block. The results indicate that the addition of grip-force feedback with gain switching enables subjects to hold both the flexible and rigid objects more stably, and it also allowed subjects who manipulated the rigid block to hold the object more delicately and to better control the motion of the remote robot's hand. Contact feedback improved the ability of subjects who manipulated the flexible cup to move the robot's arm in space, but it deteriorated this ability for subjects who manipulated the rigid block. Contact feedback also caused subjects to hold the flexible cup less stably, but the rigid block more securely. Finally, adding acceleration feedback slightly improved the subject's performance when setting the object down, as originally hypothesized; interestingly, it also allowed subjects to feel vibrations produced by the robot's motion, causing them to be more careful - hen completing the task. This study supports the utility of grip-force and high-frequency acceleration feedback in teleoperation systems and motivates further improvements to fingertip-contact-and-pressure feedback.
Autors: Rebecca P. Khurshid;Naomi T. Fitter;Elizabeth A. Fedalei;Katherine J. Kuchenbecker;
Appeared in: IEEE Transactions on Haptics
Publication date: Mar 2017, volume: 10, issue:1, pages: 40 - 53
Publisher: IEEE
 
» Efficiency Evaluation of Fully Integrated On-Board EV Battery Chargers With Nine-Phase Machines
Abstract:
A fully integrated on-board battery charger for future electric vehicles (EVs) has been recently introduced. It reutilizes all the propulsion components of an EV in charging/vehicle-to-grid (V2G) modes, it does not require any additional components or hardware reconfiguration, and charging/V2G modes are realized with zero electromagnetic torque production. Both fast (three-phase) and slow (single-phase) chargings are possible, with unity power factor operation at the grid side. The solution is based on the use of a triple three-phase machine and a nine-phase inverter/rectifier. This paper reports on the results of efficiency evaluation for the said system. Testing is performed using both a nine-phase induction machine and a nine-phase permanent magnet machine for a range of operating conditions in charging/V2G modes, with both three-phase and single-phase grid connection. Additionally, the impact of converter interleaving on the losses and efficiency is also studied. Losses are separated for different subsystems, thus providing an insight into the importance of optimization of different EV power train components from the efficiency point of view. Promising efficiencies, in the order of 90%, are achieved although none of the system components have been optimized.
Autors: Nandor Bodo;Emil Levi;Ivan Subotic;Jordi Espina;Lee Empringham;C. Mark Johnson;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 257 - 266
Publisher: IEEE
 
» Efficient 3-D Reconstruction in Ultrasound Elastography via a Sparse Iteration Based on Markov Random Fields
Abstract:
Percutaneous needle-based liver ablation procedures are becoming increasingly common for the treatment of small isolated tumors in hepatocellular carcinoma patients who are not candidates for surgery. Rapid 3-D visualization of liver ablations has potential clinical value, because it can enable interventional radiologists to plan and execute needle-based ablation procedures with real time feedback. Ensuring the right volume of tissue is ablated is desirable to avoid recurrence of tumors from residual untreated cancerous cells. Shear wave velocity (SWV) measurements can be used as a surrogate for tissue stiffness to distinguish stiffer ablated regions from softer untreated tissue. This paper extends the previously reported sheaf reconstruction method to generate complete 3-D visualizations of SWVs without resorting to an approximate intermediate step of reconstructing transverse planes. The noisy data are modeled using a Markov random field, and a computationally tractable reconstruction algorithm that can handle grids with millions of points is developed. Results from simulated ellipsoidal inclusion data show that this algorithm outperforms standard nearest neighbor interpolation by an order of magnitude in mean squared reconstruction error. Results from the phantom experiments show that it also provides a higher contrast-to-noise ratio by almost 2 dB and better signal-to-noise ratio in the stiff inclusion by over 2 dB compared with nearest neighbor interpolation and has lower computational complexity than linear and spline interpolation.
Autors: Atul Ingle;Tomy Varghese;William A. Sethares;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Mar 2017, volume: 64, issue:3, pages: 491 - 499
Publisher: IEEE
 
» Efficient Distance-Aware Influence Maximization in Geo-Social Networks
Abstract:
Given a social network and a positive integer , the influence maximization problem aims to identify a set of nodes in that can maximize the influence spread under a certain propagation model. As the proliferation of geo-social networks, location-aware promotion is becoming more necessary in real applications. In this paper, we study the distance-aware influence maximization (DAIM) problem, which advocates the importance of the distance between users and the promoted location. Unlike the traditional influence maximization problem, DAIM treats users differently based on their distances from the promoted location. In this situation, the nodes selected are different when the promoted location varies. In order to handle the large number of queries and meet the online requirement, we develop two novel index-based approaches, MIA-DA and RIS-DA, by utilizing the information over some pre-sampled query locations. MIA-DA is a heuristic method which adopts the maximum influence arborescence (MIA) model to approximate the influence calculation. In addition, different pruning strategies as well as a priority-based algorithm are proposed to significantly reduce the searching space. To i- prove the effectiveness, in RIS-DA, we extend the reverse influence sampling (RIS) model and come up with an unbiased estimator for the DAIM problem. Through carefully analyzing the sample size needed for indexing, RIS-DA is able to return a approximate solution with at least probability for any given query. Finally, we demonstrate the efficiency and effectiveness of proposed methods over real geo-social networks.
Autors: Xiaoyang Wang;Ying Zhang;Wenjie Zhang;Xuemin Lin;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Mar 2017, volume: 29, issue:3, pages: 599 - 612
Publisher: IEEE
 
» Efficient Metric Indexing for Similarity Search and Similarity Joins
Abstract:
Spatial queries including similarity search and similarity joins are useful in many areas, such as multimedia retrieval, data integration, and so on. However, they are not supported well by commercial DBMSs. This may be due to the complex data types involved and the needs for flexible similarity criteria seen in real applications. In this paper, we propose a versatile and efficient disk-based index for metric data, the S pace-filling curve and Pivot-based B-tree (SPB-tree). This index leverages the B-tree, and uses space-filling curve to cluster data into compact regions, thus achieving storage efficiency. It utilizes a small set of so-called pivots to reduce significantly the number of distance computations when using the index. Further, it makes use of a separate random access file to support a broad range of data. By design, it is easy to integrate the SPB-tree into an existing DBMS. We present efficient algorithms for processing similarity search and similarity joins, as well as corresponding cost models based on SPB-trees. Extensive experiments using both real and synthetic data show that, compared with state-of-the-art competitors, the SPB-tree has much lower construction cost, smaller storage size, and supports more efficient similarity search and similarity joins with high accuracy cost models.
Autors: Lu Chen;Yunjun Gao;Xinhan Li;Christian S. Jensen;Gang Chen;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Mar 2017, volume: 29, issue:3, pages: 556 - 571
Publisher: IEEE
 
» Efficient Programmable Pulse Shaping for $X$ -Band GaN MMIC Radar Power Amplifiers
Abstract:
This paper presents a supply modulated -band 12-W peak power transmitter that maintains an average efficiency greater than 50% for various shapes of amplitude-modulated pulses. The main power amplifier is a two-stage GaN-on-SiC MMIC with a peak efficiency of 65%, while the pulse envelope modulator is a 95% efficient hybrid 3-b power DAC implemented with GaN-on-Si transistor switches. Envelope shaping of a pulsed waveform results in improved spectral confinement of greater than 15 dB for the first sideband compared with constant-envelope pulses, with over 20 points improvement in total efficiency. The combination of supply modulation and digital predistortion is shown to result in high composite (total) efficiency of over 55%, with simultaneous high dynamic range and with flexible digitally programmable pulse shaping.
Autors: Corrado Florian;Tommaso Cappello;Daniel Niessen;Rudi Paolo Paganelli;Scott Schafer;Zoya Popović;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Mar 2017, volume: 65, issue:3, pages: 881 - 891
Publisher: IEEE
 
» Efficient Real-Time Distributed Video Coding by Parallel Progressive Side Information Regeneration
Abstract:
Distributed video coding (DVC) provides a different compression paradigm that consists of lightweight encoder and complex decoder. This compression paradigm shed a light for nowadays mobile devices which equipped with limited battery and computing resources while the corresponding multimedia service is backed up by cloud computing infrastructures. After years of developing, the coding performance and the decoding speed of DVC are still facing serious challenges, for example, DVC’s rate-distortion (RD) performance is far behind the traditional prediction based video codec (e.g., H.264) and the required decoding complexity handicaps its value in practical usage. In order to meet these challenges, we propose an efficient real-time DVC framework with progressive side information regeneration by taking GPGPU-based parallel computing into account. The proposed system can resolve one of the achilles’ heels, i.e., the large group of picture scenario, of DVC codec with good RD performance and much improved decoding speed. The Bjontegaard Delta peak signal-to-noise ratio improvement of our system is up to 2.87 dB as compared with DISCOVER codec, which is also comparable with that of the state-of-the-art optical flow-based DVC codecs. The average decoding speed goes up to 22.44 frames per second (FPS) and even up to 76.35 FPS for Hall sequence. To the best of our knowledge, this is the first DVC codec which tackles the RD performance and the decoding speed issues simultaneously.
Autors: Yun-Chung Shen;Han-Ping Cheng;Ji-Ciao Luo;Yu-Hsun Lin;Ja-Ling Wu;
Appeared in: IEEE Sensors Journal
Publication date: Mar 2017, volume: 17, issue:6, pages: 1872 - 1883
Publisher: IEEE
 
» Efficient Simulation of Nonlinear Transmission Lines via Model-Order Reduction
Abstract:
A new method is introduced for simulation of nonlinear transmission lines based on model-order reduction using the proper-orthogonal decomposition technique. An algorithm is presented for estimating the optimum order of the resulting reduced nonlinear macromodel ensuring its efficiency and accuracy. In contrast to previous publications, the order-estimation algorithm is integrated with the reduction technique leading to significant reduction in the computational cost associated with the generation of the reduced model.
Autors: Behzad Nouri;Michel S. Nakhla;Ramachandra Achar;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Mar 2017, volume: 65, issue:3, pages: 673 - 683
Publisher: IEEE
 
» Efficient Strategies for Estimating the Spatial Coherence of Backscatter
Abstract:
The spatial coherence of ultrasound backscatter has been proposed to reduce clutter in medical imaging, to measure the anisotropy of the scattering source, and to improve the detection of blood flow. These techniques rely on correlation estimates that are obtained using computationally expensive strategies. In this paper, we assess the existing spatial coherence estimation methods and propose three computationally efficient modifications: a reduced kernel, a downsampled receive aperture, and the use of an ensemble correlation coefficient. The proposed methods are implemented in simulation and in vivo studies. Reducing the kernel to a single sample improved computational throughput and improved axial resolution. Downsampling the receive aperture was found to have negligible effect on estimator variance, and improved computational throughput by an order of magnitude for a downsample factor of 4. The ensemble correlation estimator demonstrated lower variance than the currently used average correlation. Combining the three methods, the throughput was improved 105-fold in simulation with a downsample factor of 4- and 20-fold in vivo with a downsample factor of 2.
Autors: Dongwoon Hyun;Anna Lisa C. Crowley;Jeremy J. Dahl;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Mar 2017, volume: 64, issue:3, pages: 500 - 513
Publisher: IEEE
 
» Efficient Subculture Process for Adherent Cells by Selective Collection Using Cultivation Substrate Vibration
Abstract:
Cell detachment and reseeding are typical operations in cell culturing, often using trypsin exposure and pipetting, even though this process is known to damage the cells. Reducing the number of detachment and reseeding steps might consequently improve the overall quality of the culture, but to date this has not been an option. This study proposes the use of resonant vibration in the cell cultivation substrate to selectively release adherent calf chondrocyte cells: Some were released from the substrate and collected while others were left upon the substrate to grow to confluence as a subculture—without requiring reseeding. An out-of-plane vibration mode with a single nodal circle was used in the custom culture substrate. At a maximum vibration amplitude of 0.6 µm, 84.9% of the cells adhering to the substrate were released after 3 min exposure, leaving a sufficient number of cells for passage and long-term cell culture, with the greatest cell concentration along the nodal circle where the vibration was relatively quiescent. The 72-h proliferation of the unreleased cells was 20% greater in number than cells handled using the traditional method of trypsin-EDTA (0.050%) release, pipette collection, and reseeding. Due to the vibration, it was possible to reduce the trypsin-EDTA used for selective release to only 0.025%, and in doing so the cell number after 72 h of proliferation was 42% greater in number than the traditional technique.
Autors: Yuta Kurashina;Kenjiro Takemura;James Friend;Shogo Miyata;Jun Komotori;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Mar 2017, volume: 64, issue:3, pages: 580 - 587
Publisher: IEEE
 
» Efficient Wideband Spectrum sensing Based on Compressive Sensing and Multiband Signal Covariance
Abstract:
This paper a novel and efficient wideband sensing algorithm based on compression and reconstruction of the covariance matrix of the signal from the covariance matrix of the acquired samples is proposed, it allows users to sense the cognitive spectrum without a priori knowledge of signal characteristics in the radio environment. Simulation results show that the proposed method allows estimating the spectral covariance matrix of signal and from it can perform efficiently the spectrum sensing, improving performance sensing according to the detection probability, false alarm and probability of failure detection, compared with spectrum sensing algorithms based on wideband energy detection, which works at rates above or equal to the Nyquist sampling rate.
Autors: Evelio Astaiza;Hector Fabio Bermudez;Wilmar Yesid Campo;
Appeared in: IEEE Latin America Transactions
Publication date: Mar 2017, volume: 15, issue:3, pages: 393 - 399
Publisher: IEEE
 
» Efficiently Attentive Event-Triggered Systems With Limited Bandwidth
Abstract:
Event-triggered systems sample and transmit data when a state dependent criterion is violated. Many event-triggered systems are efficiently attentive, i.e., longer inter-sampling intervals are achieved as the system gets closer to its equilibrium. This property allows event-triggered systems to use fewer communication resources since control systems are usually operated around their equilibria. Efficient attentiveness, however, is not a necessary property of all event-triggered systems. To ensure efficient attentiveness, this technical note proposes an approach to design event triggers and quantization maps for nonlinear systems with transmission delays. We present sufficient conditions to guarantee input-to-state stability (ISS) of the resulting systems without exhibiting Zeno behavior.
Autors: Lichun Li;Xiaofeng Wang;Michael D. Lemmon;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1491 - 1497
Publisher: IEEE
 
» Ehren Helmet Pflugfelder
Abstract:
Technical communicators, engineers, and designers in the automotive industry, as well as researchers with expertise and interest in this book. It provides provides a framework for better understanding and explaining the ecological, economic, and political stakes invested in contemporary culture’s use and valuation of automobiles. The book constructs an ANT-inspired framework for rethinking automobility. In the manner of similar projects, such as Thinking with Bruno Latour in Rhetoric and Composition that establish ANT as a primary mode of analysis, the book achieves its purpose of recovering terms from ancient rhetoric—techne, kinesis, energeia, hyle, logistikos, metis, tyche, and kairos—for the purpose of demonstrating how they always, already accommodated analysis of human and nonhuman agents involved in activities, such as transportation use and design. For this reason, the book could serve as useful reading in courses on professional communication as it pertains to transportation or ANT, and as food for thought for automobile industry professionals.
Autors: Aimee Kendall Roundtree;Ehren Helmet Pflugfelder;
Appeared in: IEEE Transactions on Professional Communication
Publication date: Mar 2017, volume: 60, issue:1, pages: 112 - 114
Publisher: IEEE
 
» Electromagnetic Analysis and Steady-State Performance of Double-Sided Flat Linear Motor Using Soft Magnetic Composite
Abstract:
The applicability of a soft magnetic composite (SMC) material to a new double-sided buried-type interior permanent-magnet flat linear brushless motor (IPM-FLBM) with slot-phase shift is presented through the steady-state performance improvement in this paper. The IPM-FLBM using a conventional electrical solid steel is used as a base model prototype for the performance comparison. The analytic models for armature resistance, inductances of series-connected asymmetric dual three-phase windings, no-load flux linkages, and back electromotive forces (back EMFs) are investigated to derive a closed-form equation for the thrust force. The magnetic field capability due to the design parameter changes of the new SMC prototype is analyzed using two simplified nonlinear magnetic equivalent circuit (MEC) models, comparing with the base model prototype. The iron and copper losses of the SMC prototype also are investigated in terms of the thermal limitation. The steady-state performance enhanced by the reduced air-gap size is experimentally validated through the comparison of the static thrust force with that of the base model prototype.
Autors: Young-shin Kwon;Won-jong Kim;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2178 - 2187
Publisher: IEEE
 
» Electromagnetic Force Acquisition Distributed in Electric Motor to Reduce Vibration
Abstract:
A target of this study is the instantaneous electromagnetic force acquisition in the stator side to reduce the vibration. In this paper, the electromagnetic force is acquired from the displacement measured by the strain gauge. By using the switched reluctance motor which has salient poles, the displacements on both the stator and the rotor are measured. Additionally, the frequency characteristics of the sensor and waveforms at driving condition are measured and discussed. The measured results are compared with the simulation results. Thus, the effectiveness of the proposed method is examined. The proposed method is effective to acquire the instantaneous torque and radial electromagnetic force, this study enable to vibration and torque ripple reduction.
Autors: Toru Ito;Kan Akatsu;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1001 - 1008
Publisher: IEEE
 
» Eliminating Driving Distractions: Human-Computer Interaction with Built-In Applications
Abstract:
This article proposes a novel smart car demonstration platform, with a focus on the intuitive paradigm of human?computer interaction (HCI). The main objective here is to circumvent driver distraction when manipulating built-in car-appropriate applications (apps) for future smart car development. Two major development directions for a smart car's HCI are investigated and discussed in detail: 1) an in-vehicle user interface, which focuses on utilizing the user interface of a transparent windshield display to keep the driver's head up and eyes focused on the roadway, and 2) an in-vehicle interaction design, which emphasizes an intuitive interaction framework to minimize distractions while driving. This article addresses the major difficulties of each direction and discusses related challenges and solutions to achieve safety and comfort during smart car operation.
Autors: Bo-Hao Chen;Shih-Chia Huang;Wei-Ho Tsai;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Mar 2017, volume: 12, issue:1, pages: 20 - 29
Publisher: IEEE
 
» Embedded Control System for Smart Walking Assistance Device
Abstract:
This paper presents the design and implementation of a unique control system for a smart hoist, a therapeutic device that is used in rehabilitation of walking. The control system features a unique human–machine interface that allows the human to intuitively control the system just by moving or rotating its body. The paper contains an overview of the complete system, including the design and implementation of custom sensors, dc servo motor controllers, communication interfaces and embedded-system based central control system. The prototype of the complete system was tested by conducting a 6-runs experiment on 11 subjects and results are showing that the proposed control system interface is indeed intuitive and simple to adopt by the user.
Autors: Matevž Bošnak;Igor Škrjanc;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Mar 2017, volume: 25, issue:3, pages: 205 - 214
Publisher: IEEE
 
» Embedding LTE-U within Wi-Fi Bands for Spectrum Efficiency Improvement
Abstract:
Driven by growing spectrum shortage, LTE in unlicensed spectrum (LTE-U) has recently been proposed as a new paradigm to deliver better performance and experience for mobile users by extending the LTE protocol to unlicensed spectrum. In this article, we first present a comprehensive overview of the LTE-U technology, and discuss the practical challenges it faces. We summarize the existing LTE-U operation modes and analyze several means for LTE-U coexistence with Wi-Fi medium access control protocols. We further propose a novel hyper access point (HAP) that integrates the functionalities of LTE small cell base station and commercial Wi-Fi AP for deployment by cellular network operators. Our proposed LTE-U access embedding within the Wi-Fi protocol is non-disruptive to unlicensed Wi-Fi nodes and demonstrates performance benefits as a seamless and novel LTE and Wi-Fi coexistence technology in unlicensed band. We provide results to demonstrate the performance advantages of this novel LTE-U proposal.
Autors: Qimei Chen;Guanding Yu;Hesham M. Elmaghraby;Jyri Hamalainen;Zhi Ding;
Appeared in: IEEE Network
Publication date: Mar 2017, volume: 31, issue:2, pages: 72 - 79
Publisher: IEEE
 
» Emerging Power Quality Challenges Due to Integration of Renewable Energy Sources
Abstract:
Renewable energy becomes a key contributor to our modern society, but their integration to power grid poses significant technical challenges. Power quality is an important aspect of renewable energy integration. The major power quality concerns are: 1) Voltage and frequency fluctuations, which are caused by noncontrollable variability of renewable energy resources. The intermittent nature of renewable energy resources due to ever-changing weather conditions leads to voltage and frequency fluctuations at the interconnected power grid. 2) Harmonics, which are introduced by power electronic devices utilized in renewable energy generation. When penetration level of renewable energy is high, the influence of harmonics could be significant. In this paper, an extensive literature review is conducted on emerging power quality challenges due to renewable energy integration. This paper consists of two sections: 1) Power quality problem definition. Wind turbines and solar photovoltaic systems and their power quality issues are summarized. 2) Existing approaches to improve power quality. Various methods are reviewed, and the control-technology-based power quality improvement is the major focus of this paper. The future research directions for emerging power quality challenges for renewable energy integration are recommended.
Autors: Xiaodong Liang;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 855 - 866
Publisher: IEEE
 
» Enabling Mobile and Wireless Technologies for Smart Cities: Part 2
Abstract:
Autors: Ejaz Ahmed ;Muhammad Imran ;Mohsen Guizani ;Ammar Rayes ;Jaime Lloret ;Guangjie Han ;Wael Guibene ;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 12 - 13
Publisher: IEEE
 
» Enabling Technologies toward Fully LTE-Compatible Full-Duplex Radio
Abstract:
Full-duplex radio has potential to double spectral efficiency by simultaneously transmitting and receiving signals in the same frequency band, but at the expense of additional hardware and power consumption for self-interference cancellation. Hence, the deployment of a full-duplex cellular network can be realized by employing full-duplex functionality only at an eNodeB, which is supposed to have sufficient computation and power resources, and by scheduling pairs of half-duplex UEs that are in either downlink or uplink. By doing so, fast and smooth full-duplex deployment is possible while minimally affecting the legacy UEs and the rest of the network entities. In this article, we provide technical challenges and solutions for an LTE-compatible full-duplex cellular network, featuring wideband and wide dynamic range support for RF self-interference cancellation, and robust and efficient self-interference channel estimation for digital self-interference cancellation. Based on a realistic LTE-based cellular model, our full-duplex radio design is evaluated through system-level simulations and real-world testbed experiments. Simulation results show that a significant throughput gain can be achieved by the full-duplex technique despite the existence of physical limiting factors such as path loss, fading, and other-cell interference. Testbed measurements reveal that at a bandwidth of 20 MHz, self-interference cancellation up to 37 dB is achieved in the RF domain, and most of the residual self-interference is further cancelled down to the noise floor in the subsequent digital domain.
Autors: Gosan Noh;Hanho Wang;Changyong Shin;Seunghyeon Kim;Youngil Jeon;Hyunchol Shin;Jinup Kim;Ilgyu Kim;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 188 - 195
Publisher: IEEE
 
» Enclosure Transform for Interest Point Detection From Speckle Imagery
Abstract:
We present a fast enclosure transform (ET) to localize complex objects of interest from speckle imagery. This approach explores the spatial confinement on regional features from a sparse image feature representation. Unrelated, broken ridge features surrounding an object are organized collaboratively, giving rise to the enclosureness of the object. Three enclosure likelihood measures are constructed, consisting of the enclosure force, potential energy, and encloser count. In the transform domain, the local maxima manifest the locations of objects of interest, for which only the intrinsic dimension is known a priori. The discrete ET algorithm is computationally efficient, being on the order of using measuring distances across an image of ridge pixels. It involves easy and few parameter settings. We demonstrate and assess the performance of ET on the automatic detection of the prostate locations from supra-pubic ultrasound images. ET yields superior results in terms of positive detection rate, accuracy and coverage.
Autors: Yongjian Yu;Jue Wang;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Mar 2017, volume: 36, issue:3, pages: 769 - 780
Publisher: IEEE
 
» Energy Efficiency in Industrial Environments: Overview and Research Agenda
Abstract:
Energy efficiency has been the subject of discussion throughout the world, not only for optimization of process costs, but also by some crises identified in the energy matrix. On this context, a research agenda for energy efficiency can take assist effect in finding solutions to reduce energy consumption (or smart consumption) in industrial environments. Therefore, the main objective of this paper was to create a research agenda for energy efficiency in industrial environments, using, for this, systematic review of the literature as a fundamental methodology in the search for material that could enhance our understanding of the subject under study, identifying relevant texts to it. Once selected a portfolio of reading, it was possible to outline a statistical look around the literature, proposing indicators for analysis, as authors, countries, institutions, journals, keywords and topics and the development of the research agenda with major authors, themes and magazines. A research agenda on energy efficiency can be the start point for the studies of management practices focused on efficient use of energy. In this study, however, was limited to work only eitgh databases, given the importance in the engineering area.
Autors: Francielle Cristina Fenerich;Sergio E. Gouvea da Costa;Edson Pinheiro de Lima;
Appeared in: IEEE Latin America Transactions
Publication date: Mar 2017, volume: 15, issue:3, pages: 415 - 422
Publisher: IEEE
 
» Energy Efficiency of Uplink Massive MIMO Systems With Successive Interference Cancellation
Abstract:
The energy efficiency (EE) of an uplink massive multiple-input multiple-output system depends strongly on the number of antennas at base stations (BSs) and the receiver architecture. The existing research has focused on linear receivers, such as those based on zero forcing (ZF) or linear minimum mean squared error detectors. In this letter, we investigate the EE when nonlinear successive-interference cancellation (SIC) receivers are employed at the BSs and provide an asymptotic analysis of the total transmit power with ZF-SIC. We show that to achieve the same spectrum efficiency, the SIC receivers require fewer antennas at BSs, but only moderate increase of the receiver complexity. As a result, the EE with the SIC receivers can be significantly higher than that with linear receivers, as demonstrated by the numerical results.
Autors: Tianle Liu;Jun Tong;Qinghua Guo;Jiangtao Xi;Yanguang Yu;Zhitao Xiao;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 668 - 671
Publisher: IEEE
 
» Energy Efficiency Optimization for MIMO Distributed Antenna Systems
Abstract:
In this paper, we propose a transmit covariance optimization method to maximize the energy efficiency (EE) for a single-user distributed antenna system, where both the remote access units (RAUs) and the user are equipped with multiple antennas. Unlike previous related work, both the rate requirement and the RAU selection are taken into consideration. Here, the total circuit power consumption is related to the number of active RAUs. Given this setup, we first propose an optimal transmit covariance optimization method to solve the EE optimization problem under a fixed set of active RAUs. More specifically, we split this problem into three subproblems, namely, the rate maximization problem, the EE maximization problem without rate constraint, and the power minimization problem, and each subproblem can be efficiently solved. Then, a novel distance-based RAU selection method is proposed to determine the optimal set of active RAUs. Simulation results show that the performance of the proposed RAU selection is almost identical to the optimal exhaustive search method with significantly reduced computational complexity, and the performance of the proposed algorithm significantly outperforms the existing EE optimization methods.
Autors: Hong Ren;Nan Liu;Cunhua Pan;Chunlong He;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2276 - 2288
Publisher: IEEE
 
» Energy Efficient Algorithms for Real-Time Traffic Over Fading Wireless Channels
Abstract:
This paper studies the problem of using minimum power to provide satisfactory performance for real-time applications over unreliable and fading wireless channels. We demonstrate that this problem can be formulated as a linear programming problem. However, this formulation involves exponentially many constraints, and many parameters are either unavailable or difficult to compute, which makes it infeasible to employ standard techniques to solve the linear programming problem. Instead, we propose a simple online algorithm for this problem. We prove that our algorithm provides satisfactory performance to all real-time applications, and the total power consumption can be made arbitrarily close to the theoretical lower bound. Furthermore, our algorithm has very low complexity and does not require knowledge of many parameters in the linear programming problem, including the distributions of channel qualities. We further extend our algorithm to address systems where real-time applications and non-real-time ones coexist. We demonstrate that our algorithm achieves both low total power consumption and high utility for each non-real-time client while satisfying the performance requirements of real-time clients. Simulation results further provide some insights in setting important parameters of our algorithms, and demonstrate that our algorithm indeed achieves a significant reduction in power consumption.
Autors: Shuai Zuo;Han Deng;I-Hong Hou;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1881 - 1892
Publisher: IEEE
 
» Energy Efficient and Accurate Monitoring of Large-Scale Diffusive Objects in Internet of Things
Abstract:
Based on distributed sensing via energy-constrained sensor devices, the key of large-scale and shape-dynamic object monitoring is how to reduce communication costs, which is the highest related factor to energy consumption. For achieving this goal, we propose a novel detection mechanism based on the convex hull algorithm that has a strong aspect for reducing the number of (geographic) sensing points to be transmitted to base stations for figuring out a large-scale object. As the convex hull only could recognize convex shapes, we develop methods to not only detect shape loss being a convex but recovery original boundary. That is, our mechanism could take both low communication cost and high detection reliability of large-scale objects.
Autors: Seungmin Oh;Jeongcheol Lee;Soochang Park;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 612 - 615
Publisher: IEEE
 
» Energy Efficient D2D Communications in Dynamic TDD Systems
Abstract:
Device-to-device (D2D) communication is a promising technology for improving the performance of proximity-based services. This paper demonstrates how the integration of D2D communication in cellular systems operating under dynamic time division duplex (TDD) can improve energy efficiency. We perform joint optimization of mode selection, uplink/downlink transmission period, and power allocation to minimize the transmission energy consumption while satisfying a traffic requirement. Solutions are developed for two scenarios: with and without interference among D2D communications. Both formulations are expressed as mixed-integer nonlinear programming problems, which are NP-hard in general. We exploit problem structure to develop efficient solutions for both scenarios. For the interference-free case, we design algorithms that find the optimal solution in polynomial time. When considering interference, we propose a customized solver based on branch-and-bound that reduces the search complexity by taking advantage of the problem-specific proprieties. We complement this solver by a more practical heuristic algorithm. Simulation results demonstrate that D2D communications in dynamic TDD systems can yield significant energy savings and improved spectral efficiency compared with the traditional cellular communication. Furthermore, we give analytical characterizations of the receiver locations relative to a given transmitter where D2D communication is optimal. These regions can be surprisingly large and not necessarily circular.
Autors: Demia Della Penda;Liqun Fu;Mikael Johansson;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 1260 - 1273
Publisher: IEEE
 
» Energy Harvesting-Based D2D-Assisted Machine-Type Communications
Abstract:
Supporting massive numbers of machine-type communication (MTC) devices poses several challenges for future 5G networks, including network control, scheduling, and powering these devices. A potential solution is to offload MTC traffic onto device-to-device (D2D) communication links to better manage radio resources and reduce MTC devices’ energy consumption. However, this approach requires D2D users to use their own limited energy to relay MTC traffic, which may be undesirable. This motivates us to exploit recent advancements in RF energy harvesting for powering D2D relay transmissions. In this paper, we consider a D2D communication as an underlay to the cellular network, where D2D users access a fraction of the spectrum occupied by cellular users. This underlay model presents a fundamental trade-off: to protect cellular users, the spectrum available to D2D users needs to be reduced, which limits the number of D2D transmissions, but increases the amount of time that D2D users can spend harvesting energy to support MTC traffic. We study this trade-off by characterizing the spectral efficiency of MTC, D2D, and cellular users using stochastic geometry. The optimal spectrum partition factor is characterized to achieve fairness and balance in the network, while increasing the average MTC spectral efficiency.
Autors: Rachad Atat;Lingjia Liu;Nicholas Mastronarde;Yang Yi;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 1289 - 1302
Publisher: IEEE
 
» Energy Management in Multi-Microgrid Systems—Development and Assessment
Abstract:
The optimal management of energy generation/consumption in modern distribution systems has gained attention in the smart grid era. This paper presents optimized and coordinated strategies for performing and assessing energy management in multi-microgrid systems. The energy management process is formulated for multi-microgrid systems that simultaneously incorporate several energy generation/consumption units, including different types of distributed generators (DGs), energy storage units, electric vehicles (EVs), and demand response. Due to the probabilistic nature of some loads (e.g., EVs) and generators (e.g., wind turbine and photovoltaic (PV) modules), a novel probabilistic index is defined to measure the success of energy management scenarios in terms of cost minimization. Moreover, by using the new index, common types of energy controllers, such as DGs, storage units, EVs and demand side management are implemented simultaneously and individually, in a system, and the effect of each addition on the defined index and on operational costs is investigated. Finally, the robustness of the process to the load and generation prediction errors is investigated.
Autors: Seyed Ali Arefifar;Martin Ordonez;Yasser Abdel-Rady I. Mohamed;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 910 - 922
Publisher: IEEE
 
» Energy Storage Modeling for Distribution Planning
Abstract:
Storage is being proposed to solve many issues on the electric power grid, especially those issues related to renewable generation such as wind and solar generation. Some North American state and provincial regulators are requiring large amounts of storage to be installed to support anticipated needs of the power grid. Much of that new storage is expected to be connected to distribution feeders. Distribution planners lack tools and methods to assess storage impact on distribution system capacity, reliability, and power quality. Planners are accustomed to static power flow calculations, but accurate analysis of storage requires sequential-time simulation. This paper describes modeling storage for various types of simulations on distribution systems for different time frames typically involved. The basic impact on capacity and voltage regulation can generally be evaluated in simulations with 15-min to 1-h intervals. Evaluations of smoothing of renewable generation variations may require simulations with time step sizes of 1 min or less. Evaluations of such things as frequency control of microgrids and performance during transient disturbances will require dynamics analysis in intervals ranging from seconds down to microseconds. This paper is a summary of recent Electric Power Research Institute research in modeling energy storage for planning studies.
Autors: Roger C. Dugan;Jason A. Taylor;Davis Montenegro;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 954 - 962
Publisher: IEEE
 
» Energy-Efficient Localization and Tracking of Mobile Devices in Wireless Sensor Networks
Abstract:
Wireless sensor networks (WSNs) are effective for locating and tracking people and objects in various industrial environments. Since energy consumption is critical to prolonging the lifespan of WSNs, we propose an energy-efficient LOcalization and Tracking (eLOT) system, using low-cost and portable hardware to enable highly accurate tracking of targets. Various fingerprint based approaches for localization and tracking are implemented in eLOT. To achieve high energy efficiency, a network-level scheme coordinating collision and interference is proposed. On the other hand, based on the location information, mobile devices in eLOT can quickly associate with the specific channel in a given area, while saving energy by avoiding unnecessary transmission. Finally, a platform based on TI CC2530 and the Linux operating system is built to demonstrate the effectiveness of our proposed scheme in terms of localization accuracy and energy efficiency.
Autors: Kan Zheng;Huijian Wang;Hang Li;Wei Xiang;Lei Lei;Jian Qiao;Xuemin Sherman Shen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2714 - 2726
Publisher: IEEE
 
» Energy-Efficient Power Delivery System Paradigms for Many-Core Processors
Abstract:
The design of power delivery system plays a crucial role in guaranteeing the proper functionality of many-core processor systems. The power loss suffered on power delivery has become a salient part of total power consumption, and the energy efficiency of a highly dynamic system has been significantly challenged. Being able to achieve a fast response time and multiple voltage domain control, on-chip voltage regulators (VRs) have become popular choices to enable fine-grain power management, which also enlarge the design space of power delivery systems. This paper analytically studies different power delivery system paradigms and power management schemes in terms of energy efficiency, area overhead, and power pin occupation. The analysis shows that compared to the conventional paradigm with off-chip VRs, hybrid paradigms with both on-chip and off-chip VRs are able to maintain high efficiency in a larger range of workloads, though they suffer from low efficiency at light workload. Employed with the quantized power management scheme, the hybrid paradigm can improve the system energy efficiency at light workload by a maximum of 136% compared to the traditional load balanced scheme. Besides this, the in-package (iP) hybrid paradigm further shows its advantage in reducing the physical overheads. The results reveal that at 120 W workload, it occupies only a 10.94% total footprint area or 39.07% power pins of that of the off-chip paradigm. We conclude that the iP hybrid paradigm achieves the best tradeoffs between efficiency, physical overhead, and realization of fine-grain power management.
Autors: Haoran Li;Xuan Wang;Jiang Xu;Zhe Wang;Rafael K. V. Maeda;Zhehui Wang;Peng Yang;Luan H. K. Duong;Zhifei Wang;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Mar 2017, volume: 36, issue:3, pages: 449 - 462
Publisher: IEEE
 
» Energy-Efficient Resource Allocation for Mobile-Edge Computation Offloading
Abstract:
Mobile-edge computation offloading (MECO) off-loads intensive mobile computation to clouds located at the edges of cellular networks. Thereby, MECO is envisioned as a promising technique for prolonging the battery lives and enhancing the computation capacities of mobiles. In this paper, we study resource allocation for a multiuser MECO system based on time-division multiple access (TDMA) and orthogonal frequency-division multiple access (OFDMA). First, for the TDMA MECO system with infinite or finite cloud computation capacity, the optimal resource allocation is formulated as a convex optimization problem for minimizing the weighted sum mobile energy consumption under the constraint on computation latency. The optimal policy is proved to have a threshold-based structure with respect to a derived offloading priority function, which yields priorities for users according to their channel gains and local computing energy consumption. As a result, users with priorities above and below a given threshold perform complete and minimum offloading, respectively. Moreover, for the cloud with finite capacity, a sub-optimal resource-allocation algorithm is proposed to reduce the computation complexity for computing the threshold. Next, we consider the OFDMA MECO system, for which the optimal resource allocation is formulated as a mixed-integer problem. To solve this challenging problem and characterize its policy structure, a low-complexity sub-optimal algorithm is proposed by transforming the OFDMA problem to its TDMA counterpart. The corresponding resource allocation is derived by defining an average offloading priority function and shown to have close-to-optimal performance in simulation.
Autors: Changsheng You;Kaibin Huang;Hyukjin Chae;Byoung-Hoon Kim;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1397 - 1411
Publisher: IEEE
 
» Energy-Efficient Resource Allocation in D2D Underlaid Cellular Uplinks
Abstract:
In this letter, we study the joint channel allocation and power control problem to maximize the energy efficiency (EE) of device-to-device (D2D) links in a D2D underlaid cellular network. Due to the location dispersion of D2D pairs and short-distance D2D transmission, it should be preferred that multiple D2D pairs can simultaneously share the resource with cellular users (CUs). To address the nonconvexity of the EE maximization problem, we divide the original problem into two subproblems and propose an iterative algorithm with low complexity to solve it. Simulation results show that the proposed algorithm converges rapidly and the EE of D2D links can be significantly improved compared with existing methods especially for an increasing number of CUs.
Autors: Hao Xu;Wei Xu;Zhaohui Yang;Yijin Pan;Jianfeng Shi;Ming Chen;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 560 - 563
Publisher: IEEE
 
» Energy-Efficient Scheduling for mmWave Backhauling of Small Cells in Heterogeneous Cellular Networks
Abstract:
Heterogeneous cellular networks (HCNs) are emerging as a promising candidate for the fifth-generation (5G) mobile network. With base stations (BSs) of small cells densely deployed, the cost-effective, flexible, and green backhaul solution has become one of the most urgent and critical challenges. With vast amounts of spectrum available, wireless backhaul in the millimeter-wave (mmWave) band is able to provide transmission rates of several gigabits per second. The mmWave backhaul utilizes beamforming to achieve directional transmission, and concurrent transmissions under low interlink interference can be enabled to improve network capacity. To achieve an energy-efficient solution for mmWave backhauling, we first formulate the problem of minimizing the energy consumption via concurrent transmission scheduling and power control into a mixed integer nonlinear program (MINLP). Then, we develop an energy-efficient and practical mmWave backhauling scheme, which consists of the maximum independent set (MIS)-based scheduling algorithm and the power control algorithm. We also theoretically analyze the conditions that our scheme reduces energy consumption, as well as the choice of the interference threshold. Through extensive simulations under various traffic patterns and system parameters, we demonstrate the superior performance of our scheme in terms of energy efficiency and analyze the choice of the interference threshold under different traffic loads, BS distributions, and the maximum transmission power.
Autors: Yong Niu;Chuhan Gao;Yong Li;Li Su;Depeng Jin;Yun Zhu;Dapeng Oliver Wu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2674 - 2687
Publisher: IEEE
 
» Energy-Efficient TCAM Search Engine Design Using Priority-Decision in Memory Technology
Abstract:
Ternary content-addressable memory (TCAM)-based search engines generally need a priority encoder (PE) to select the highest priority match entry for resolving the multiple match problem due to the don’t care (X) features of TCAM. In contemporary network security, TCAM-based search engines are widely used in regular expression matching across multiple packets to protect against attacks, such as by viruses and spam. However, the use of PE results in increased energy consumption for pattern updates and search operations. Instead of using PEs to determine the match, our solution is a three-phase search operation that utilizes the length information of the matched patterns to decide the longest pattern match data. This paper proposes a promising memory technology called priority-decision in memory (PDM), which eliminates the need for PEs and removes restrictions on ordering, implying that patterns can be stored in an arbitrary order without sorting their lengths. Moreover, we present a sequential input-state (SIS) scheme to disable the mass of redundant search operations in state segments on the basis of an analysis distribution of hex signatures in a virus database. Experimental results demonstrate that the PDM-based technology can improve update energy consumption of nonvolatile TCAM (nvTCAM) search engines by 36%–67%, because most of the energy in these search engines is used to reorder. By adopting the SIS-based method to avoid unnecessary search operations in a TCAM array, the search energy reduction is around 64% of nvTCAM search engines.
Autors: Hsiang-Jen Tsai;Keng-Hao Yang;Yin-Chi Peng;Chien-Chen Lin;Ya-Han Tsao;Meng-Fan Chang;Tien-Fu Chen;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 962 - 973
Publisher: IEEE
 
» Energy-Efficient Transmission Design in Non-orthogonal Multiple Access
Abstract:
Non-orthogonal multiple access (NOMA) is considered as a promising technology for improving the spectral efficiency in fifth-generation systems. In this correspondence, we study the benefit of NOMA in enhancing energy efficiency (EE) for a multiuser downlink transmission, wherein the EE is defined as the ratio of the achievable sum rate of the users to the total power consumption. Our goal is to maximize EE subject to a minimum required data rate for each user, which leads to a nonconvex fractional programming problem. To solve it, we first establish the feasible range of the transmitting power that is able to support each user's data rate requirement. Then, we propose an EE-optimal power allocation strategy that maximizes EE. Our numerical results show that NOMA has superior EE performance in comparison with conventional orthogonal multiple access.
Autors: Yi Zhang;Hui-Ming Wang;Tong-Xing Zheng;Qian Yang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2852 - 2857
Publisher: IEEE
 
» Energy-Efficient VLSI Realization of Binary64 Division With Redundant Number Systems
Abstract:
VLSI realizations of digit-recurrence binary division usually use redundant representation of partial remainders and quotient digits. The former allows for fast carry-free computation of the next partial remainder, and the latter leads to less number of the required divisor multiples. In studying the previous relevant works, we have noted that the binary carry-save (CS) number system is prevalent in the representation of partial remainders, and redundant high radix representation of quotient digits is popular in order to reduce the cycle count. In this paper, we explore a design space containing four division architectures. These are based on binary CS or radix-16 signed digit (SD) representations of partial remainders. On the other hand, they use full or partial precomputation of divisor multiples. The latter uses smaller multiplexer at the cost two extra adders, where one of the operands is constant within all cycles. The quotient digits are represented by radix-16 [−9, 9] SDs. Our synthesis-based evaluation of VLSI realizations of the best previous relevant work and the four proposed designs show reduced power and energy figures in the proposed designs at the cost of more silicon area and delay measures. However, our energy-delay product is 26%–35% less than that of the reference work.
Autors: Saba Amanollahi;Ghassem Jaberipur;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 954 - 961
Publisher: IEEE
 
» Engage Others or Leave it to the Source? On Optimal Message Replication in DTNs Under Imperfect Cooperation
Abstract:
The message replication strategy, namely the way message copies are generated and diffused (a.k.a. sprayed) in the network, is a fundamental, yet not thoroughly explored, component of all multi-copy message forwarding schemes in opportunistic networks. Whereas almost all related protocols rely to some extent on the assistance of intermediate nodes for relaying message copies towards their destination, the generation of new message copies may either involve them or be carried out exclusively by the message source. This paper first formulates and solves analytical models for the performance of the two most popular message spraying strategies under imperfect node cooperation and homogeneous exponentially distributed pairwise node inter-contact times. Numerical results suggest that as the node cooperation decreases source replication consistently outperforms binary replication, i.e., the optimal variant of intermediate node-assisted replication under nominal conditions of full node cooperation. The analytical conclusions are also verified for more realistic node mobility patterns through trace-driven experimentation. We then formulate the ideal selection of replication mode as a finite-horizon Continuous Time Markov Decision Process with restricted decision epochs and solve it for the optimal spraying policy. The optimal policy coincides with the binary-(source-) spraying in the presence of few (resp. many) misbehaving nodes. To better approximate it at intermediate levels of misbehavior intensity, we introduce and analyze a simple static spraying policy permitting source-destination space-time paths of up to three hops. Our work deepens the understanding of a core operation embedded in a broad range of multi-copy DTN forwarding protocols. At the same time, it advocates a more thorough approach to the design and evaluation of DTN for- arding that accounts for beyond-nominal conditions.
Autors: Merkourios Karaliopoulos;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Mar 2017, volume: 16, issue:3, pages: 730 - 743
Publisher: IEEE
 
» Engineering Students' Perceptions of Graduate Attributes: Perspectives From Two Educational Paths
Abstract:
This study aimed to provide insights on the perceptions of engineering students from two educational paths in Singapore of desired graduate attributes by employers. Research questions: (1) Do graduates from the polytechnic and junior college paths have similar perceptions with regard to the ranking of desirable graduate attributes? (2) If not, in what ways are their perceptions different? Literature review: A review of literature on employers' ranking of desirable graduate attributes revealed mismatches in employers' and graduates' rankings. There has not been any published study on student awareness of employability skills in Singapore in particular. Hence, this study investigated the perceptions of final-year engineering students from two different educational paths of their ranking of graduate attributes. Methodology: The students were asked to rank eight attributes and explain their ranking from an employer's perspective. Results: The findings show that communication, teamwork, and problem-solving were ranked the top three desirable attributes by both groups of students. However, polytechnic students seem to reflect greater familiarity and confidence in tackling workplace requirements compared to junior college students. The implications of the findings are presented.
Autors: Chien-Ching Lee;Soo-Fun Chin;
Appeared in: IEEE Transactions on Professional Communication
Publication date: Mar 2017, volume: 60, issue:1, pages: 42 - 55
Publisher: IEEE
 
» Enhanced C-RAN Using D2D Network
Abstract:
With the surge in smartphone sensing, wireless networking, and mobile social networking techniques, mobile crowdsensing (MCS) has become a promising paradigm for 5G networks. An MCS system's service quality heavily depends on the platform, which brings the users under a common cloud with very low delay. Therefore, MCS needs a new platform that brings the best not only from the user's perspective, but also from the operator's perspective. In this article, we propose a novel architecture for MCS by combining two technologies, those being C-RAN and D2D. C-RAN is a promising enabling technology that can at the same time cope with the ever increasing mobile traffic demand and reduce the surging costs experienced by service operators. In spite of the many advantages offered by C-RAN, one of the main concerns for operators is its associated fronthaul delay. To handle such delay, we come across this D2D solution in C-RAN networks. D2D is adopted as an effective candidate for very low delay between links and has already provided evidence of its potential for novel business opportunities. This article shows, together with standardization aspects, how combining C-RAN and D2D technologies can help to solve the delay issue and fulfill most of the targets specified for 5G networks in terms of delay, capacity, energy efficiency, mobility, and cost.
Autors: Kazi Mohammed Saidul Huq;Shahid Mumtaz;Jonathan Rodriguez;Paulo Marques;Bismark Okyere;Valerio Frascolla;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 100 - 107
Publisher: IEEE
 
» Enhanced Carrier Collection in Silver Nanoparticle Embedded Zinc Oxide Nanorod Top Electrodes for Thin-Film Photovoltaic Devices
Abstract:
Cu(In, Ga)Se2 solar cells are the representative of high efficient thin-film solar cell with energy conversion efficiency of over 22%. However, nowadays, top electrodes of solar cells gradually become the performance limitation for optimized devices. The Al-doped ZnO thin film is widely used as a transparent top electrode in Cu(In, Ga)Se2, but there are still some techniques and electrical property issues. In this letter, we establish a ZnO/Ag/ZnO:Al multilayer top electrode, composed of ZnO nanorod arrays, Ag nanoparticles, and ZnO:Al thin films. Such multilayer top electrode was applied on Cu(In, Ga)Se2 thin-film solar cells and the devices yield a higher efficiency from 6.79% to 8.52%. Importantly, we also propose that the enhanced electronic carrier concentration in such ZnO/Ag/ZnO:Al top electrode aids the performance of solar cells. Therefore, well-designed ZnO-based top electrodes offer the opportunity to remove the bottleneck of improving the solar cell efficiency.
Autors: Xuan Huang;Wenzhi Chen;Jia Feng;Qiang Xu;Wei Chen;Xin Cui;Bea-Heng Tseng;Daqin Yun;Qijin Cheng;Chao Chen;Jie Liu;Yangyang Fu;Fengyan Zhang;
Appeared in: IEEE Electron Device Letters
Publication date: Mar 2017, volume: 38, issue:3, pages: 349 - 352
Publisher: IEEE
 
» Enhanced Deployment Algorithms for Heterogeneous Directional Mobile Sensors in a Bounded Monitoring Area
Abstract:
Good deployment of sensors empowers the network with effective monitoring ability. Different from omnidirectional sensors, the coverage region of a directional sensor is determined by not only the sensing radius (distance), but also its sensing orientation and spread angle. Heterogeneous sensing distances and spread angles are likely to exist among directional sensors, to which we refer as heterogeneous directional sensors. In this paper, we target on a bounded monitoring area and deal with heterogeneous directional sensors equipped with locomotion and rotation facilities to enable the sensors self-deployment. Two Enhanced Deployment A lgorithms, EDA-I and EDA-II, are proposed to achieve high sensing coverage ratio in the monitored field. EDA-I leverages the concept of virtual forces (for sensors movements) and virtual boundary torques (for sensors rotations), whereas EDA-II combines Voronoi diagram directed movements and boundary torques guided rotations. EDA-I computations can be centralized or distributed that differ in required energy and execution time, whereas EDA-II only allows centralized calculations. Our EDA-II outperforms EDA-I in centralized operations, while EDA-I can be adapted into a distributed deployment algorithm without requiring global information and still achieves comparably good coverage performance to its centralized version. To the best of our knowledge, this is perhaps the first work to employ movements followed by rotations for sensors self-deployment. Performance results demonstrate that our enhanced deployment mechanisms are capable of providing desirable surveillance level, while consuming moderate moving and rotating energy under reasonable execution time.
Autors: Ting-Yu Lin;Hendro Agus Santoso;Kun-Ru Wu;Gui-Liu Wang;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Mar 2017, volume: 16, issue:3, pages: 744 - 758
Publisher: IEEE
 
» Enhanced Pumped Hydro Storage Utilization Using Policy Functions
Abstract:
While there are growing interests in using pumped hydro storage to facilitate the integration of renewable resources, the flexibility of storage is not being fully utilized by existing energy and market management systems. Today, one common approach to operate pumped hydro storage is to determine schedules for a future time horizon based on a look-ahead operational planning stage, with limited adjustment in real-time. However, as renewable penetration levels increase, such approaches do not fully utilize the flexibility of pumped hydro storage. In this paper, a policy function approach is proposed to enhance the utilization of pumped hydro storage in real-time operations. The performance of the approach is evaluated and compared with other benchmark approaches using the IEEE RTS 24-bus system. The result shows that the policy function approach is effective in utilizing the flexibility of pumped hydro storage and has minimal added computational complexity to the existing dispatch process.
Autors: Nan Li;Kory W. Hedman;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1089 - 1102
Publisher: IEEE
 
» Enhanced Temperature Monitoring System for Sinter in a Rotatory Cooler
Abstract:
Temperature monitoring of moving material is a complex procedure that provides relevant information about thermal behavior. Temperature monitoring requires accurate tracking of moving material to calculate its temperature so temperature curves can be calculated. This paper proposes a temperature monitoring system for sinter material, with multiple potential applications in a number of different areas. First, a calibration procedure that translates images to real world units is developed. Calibration enables the calculation of images without perspective projection that provide reliable geometric information. Moreover, with these transformed images, the model used to estimate movement is greatly simplified. Second, a tracking procedure consisting of feature detection, feature matching, and model estimation is applied to the rectified images. Finally, multiple temperature decay curves are calculated simultaneously, providing relevant information about cooling behavior. Features extracted from these curves can be used to detect abnormal cooling behaviors, and to control and regulate the sintering process. Tests of the proposed system indicate excellent performance in terms of calibration accuracy, temperature measurement, description of the cooling patterns, and detection of abnormal conditions.
Autors: Rubén Usamentiaga;Daniel F. Garcia;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1589 - 1597
Publisher: IEEE
 
» Enhanced Time-Modulated Arrays for Harmonic Beamforming
Abstract:
One of the primary features of time-modulated arrays (TMAs) is their ability to adapt their harmonic patterns to exploit the angular diversity of multipath wireless channels. In such a case, the TMA excitations must provide an adequate level of harmonic windowing in order to safeguard both the antenna efficiency and the signal-to-noise ratio at reception. In this work, we propose to time-modulate the array excitations with periodic sum-of-weighted-cosine (SWC) pulses rather than with the periodic rectangular pulses corresponding to the on–off switches of conventional TMAs. We show that how the larger flexibility of the SWC pulses allows for a more versatile design of the TMA harmonic radiation patterns without penalizing the array gain for each exploited harmonic.
Autors: Roberto Maneiro-Catoira;Julio C. Brégains;José A. García-Naya;Luis Castedo;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Mar 2017, volume: 11, issue:2, pages: 259 - 270
Publisher: IEEE
 

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