Electrical and Electronics Engineering publications abstract of: 01-2017 sorted by title, page: 6

» Diversity-Multiplexing Tradeoff in an Interweave Multiuser Cognitive Radio System
Abstract:
In an interweave cognitive radio system, the spectrum sensing performance affects the rate and reliability of data transmission. In wireless communications, the tradeoff between the reliability and data rate can be evaluated by diversity-multiplexing tradeoff (DMT) analysis. In this paper, through the analysis of the error probability at the secondary receiver, we derive the DMT for the multiple-access channel and user-selection schemes in an interweave multiuser cognitive radio system considering the spectrum sensing effect on the rate and reliability. We show that the DMT of the system can be improved by cooperative spectrum sensing. Simulations also approve our analytical results.
Autors: Atefeh Roostaei;Mostafa Derakhtian;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 389 - 399
Publisher: IEEE
 
» DIVERT: A Distributed Vehicular Traffic Re-Routing System for Congestion Avoidance
Abstract:
Centralized solutions for vehicular traffic re-routing to alleviate congestion suffer from two intrinsic problems: scalability, as the central server has to perform intensive computation and communication with the vehicles in real-time; and privacy, as the drivers have to share their location as well as the origins and destinations of their trips with the server. This article proposes DIVERT, a distributed vehicular re-routing system for congestion avoidance. DIVERT offloads a large part of the re-routing computation at the vehicles, and thus, the re-routing process becomes practical in real-time. To take collaborative re-routing decisions, the vehicles exchange messages over vehicular ad hoc networks. DIVERT is a hybrid system because it still uses a server and Internet communication to determine an accurate global view of the traffic. In addition, DIVERT balances the user privacy with the re-routing effectiveness. The simulation results demonstrate that, compared with a centralized system, the proposed hybrid system increases the user privacy by 92 percent on average. In terms of average travel time, DIVERT's performance is slightly less than that of the centralized system, but it still achieves substantial gains compared to the no re-routing case. In addition, DIVERT reduces the CPU and network load on the server by 99.99 and 95 percent, respectively.
Autors: Juan (Susan) Pan;Iulian Sandu Popa;Cristian Borcea;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 58 - 72
Publisher: IEEE
 
» DIY film digitizer [Resources]
Abstract:
My grandfather Leo was a self-taught electrical engineer and IEEE member who designed control systems for tire factories. He was also an avid photographer, and his eight children—and later, his grandchildren— were among his favorite subjects, right up to his death in 1974, when I was 5. Fast‑forward to 2013: During a move, my uncle uncovered a trove of more than 130 reels of Leo’s 8-mm and 16-mm home movies, some dating back to 1939. While commercial conversion services exist, converting so many reels would have been pretty expensive, so my cousin and I set out to preserve them digitally ourselves.
Autors: Joe Herman;
Appeared in: IEEE Spectrum
Publication date: Jan 2017, volume: 54, issue:1, pages: 17 - 18
Publisher: IEEE
 
» DOA Estimation Based on Combined Unitary ESPRIT for Coprime MIMO Radar
Abstract:
Direction of arrival (DOA) estimation for coprime multiple-input multiple-output radar is studied, and a combined unitary estimation of signal parameters via rotational invariance technique (ESPRIT)-based algorithm is proposed. The transmitter and the receiver adopt coprime arrays, which are sparse but still uniform. Therefore, unitary ESPRIT is first used to obtain arbitrary ambiguous DOA estimations based on the rotational invariances of transmit and receive arrays, respectively. After recovering all the other estimations, unique DOA estimation is achieved by finding the coincide results from transmit and receive arrays based on the coprimeness. The proposed algorithm obtains more accurate DOA estimation, achieves higher angle resolution, and identifies more targets than conventional methods. Multiple simulations are conducted to verify the improvement of the proposed algorithm.
Autors: Jianfeng Li;Defu Jiang;Xiaofei Zhang;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 96 - 99
Publisher: IEEE
 
» Doubly Fed Induction Generator System Resonance Active Damping Through Stator Virtual Impedance
Abstract:
The penetration of wind power has been increasing in the past few decades all over the world. Under certain nonideal situations where the wind power generation system is connected to the weak grid, the doubly fed induction generator (DFIG)-based wind power generation system may suffer high-frequency resonance (HFR) due to the impedance interaction between the DFIG system and the weak grid network whose impedance is comparatively large. Thus, it is important to implement an active damping for the HFR in order to ensure a safe and reliable operation of both the DFIG system and the grid-connected converters/loads. This paper analyzes and explains first the HFR phenomenon between the DFIG system and a parallel compensated weak network (series RL + shunt C). Then, on the basis of the DFIG system impedance modeling, an active damping control strategy is introduced by inserting a virtual impedance (positive capacitor or negative inductor) into the stator branch through stator current feedforward control. The effectiveness of the DFIG system active damping control is verified by a 7.5 kW experimental downscaled DFIG system, and simulation results of a commercial 2 MW DFIG system is provided as well.
Autors: Yipeng Song;Xiongfei Wang;Frede Blaabjerg;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 125 - 137
Publisher: IEEE
 
» Downscaling of Land Surface Temperature Using Airborne High-Resolution Data: A Case Study on Aprilia, Italy
Abstract:
A regression-based downscaling of land surface temperature was developed over the heterogeneous urban area of Aprilia, Central Italy, using high resolution (HR) airborne data. Airborne sensors provided thermal and visible–near infrared (VNIR) measurements at 2-m pixel size. Coarse resolution images at 40, 30, and 20 m, upscaled by aggregation from the native airborne data, were sharpened to the finer resolution of 2 m. The main core of the downscaling method is the use of the spectral mixture analysis (SMA) to derive fractional pixel composition as predictors of the regression scheme. The HR VNIR data allow choosing detailed land cover types in the application of SMA, such as bright/dark roofs, and the benefit of this detailed selection is proved. The estimation error of the custom technique improves of about 10%–15% with respect to a classical regression downscaling.
Autors: Stefania Bonafoni;Grazia Tosi;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 107 - 111
Publisher: IEEE
 
» Drawing the Most Power From Low-Cost Single-Well 1-mm2 CMOS Photovoltaic Cells
Abstract:
Photovoltaic (PV) cells can generate 100× more power from light than other transducers can from motion, radiation, and heat. Although custom multijunction nonsilicon and multiwell complementary metal–oxide–semiconductor (CMOS) cells output more power, single-well process technologies cost less. Amorphous cells cost even less but output less power. However, with only a small window of light available, tiny CMOS cells output little. This brief explores and proposes open-terminal single-well CMOS PV cell configurations that output more power than competing low-cost CMOS cells in literature. Measurements with 0.35- single-well CMOS cells show that deeper and lighter doped junctions generate higher power than shallower junctions, and double-junction configurations output even higher power. This is why sunlight on N+ in P substrate and N well in P substrate cells outputs 6 and 98 and on shorted and open-terminal P+ in N well in P substrate structures outputs 132 . Opening the P+ terminal outputs even more power because P+ metal, which blocks light, is no longer necessary.
Autors: Rajiv Damodaran Prabha;Gabriel A. Rincón-Mora;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 46 - 50
Publisher: IEEE
 
» Drive Now, Text Later: Nonintrusive Texting-While-Driving Detection Using Smartphones
Abstract:
Texting-while-driving (T&D) is one of the top dangerous behaviors for drivers. Many interesting systems and mobile phone applications have been designed to help to detect or combat T&D. However, for a T&D detection system to be practical, a key property is its capability to distinguish driver's mobile phone from passengers’. Existing solutions to this problem generally rely on the user's manual input, or utilize specific localization devices to determine whether a mobile phone is at the driver's location. In this paper, we propose a method which is able to detect T&D automatically without using any extra devices. The idea is very simple: when a user is composing messages, the smartphone embedded sensors (i.e., gyroscopes, accelerometers, and GPS) collect the associated information such as touchstrokes, holding orientation and vehicle speed. This information will then be analyzed to see whether there exists some specific T&D patterns. Extensive experiments have been conducted by different persons and in different driving scenarios. The results show that our approach can achieve a good detection accuracy with low false positive rate. Besides being infrastructure-free and with high accuracy, the method does not access the content of messages and therefore is privacy-preserving.
Autors: Xuefeng Liu;Jiannong Cao;Shaojie Tang;Zongjian He;Jiaqi Wen;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 73 - 86
Publisher: IEEE
 
» Driver Topologies for RF Doherty Power Amplifiers
Abstract:
In this letter, class-B, embedded class-B, and Doherty driver topologies are investigated for RF Doherty Power Amplifiers (PAs). The investigation is firstly conducted theoretically and by simulations and then verified by design and implementation of the different topologies at 2.1 GHz using GaN-HEMT transistors. The results show that the highest lineup efficiency can be achieved when using a Doherty driver. Modulated measurements using the same LTE signal and the same digital per-distorter (DPD), show about 2% and 4% higher average lineup efficiency when the Doherty driver is used compared to the class-B and embedded class-B drivers, respectively.
Autors: Paul Saad;Zahra Asghari;Christian Fager;Hossein Mashad Nemati;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 67 - 69
Publisher: IEEE
 
» Driving Toward Accessibility: A Review of Technological Improvements for Electric Machines, Power Electronics, and Batteries for Electric and Hybrid Vehicles
Abstract:
Electric and hybrid vehicles continue to demand a considerable share of the automotive market. This movement has been enabled by the recent technological improvements in the areas of electric motors, power electronics, and energy storage. While many electric vehicles (EVs) are on the market, they are not as cost competitive as conventional vehicles, and affordable cost is necessary for large-scale market penetration. For this to become a reality, continued research is needed to develop new cost-efficient technologies. This article presents the metrics and benchmarks used to gauge the performance of various electric drivetrains. In addition, current state-of-the-art technologies are presented in terms of these metrics as well as the future goals and trends in the industry. With ongoing development, the market for electric and hybrid vehicles will continue to increase.
Autors: Bulent Sarlioglu;Casey T. Morris;Di Han;Silong Li;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jan 2017, volume: 23, issue:1, pages: 14 - 25
Publisher: IEEE
 
» Drone Classification Using Convolutional Neural Networks With Merged Doppler Images
Abstract:
We propose a drone classification method based on convolutional neural network (CNN) and micro-Doppler signature (MDS). The MDS only presents Doppler information in time domain. The frequency domain representation of MDS is called as cadence-velocity diagram (CVD). To analyze the Doppler information of drone in time and frequency domain, we propose a new image by merging MDS and CVD, as merged Doppler image. GoogLeNet, a CNN structure, is utilized for the proposed image data set because of its high performance and optimized computing resources. The image data set is generated by the returned Ku-band frequency modulation continuous wave radar signal. Proposed approach is tested and verified in two different environments, anechoic chamber and outdoor. First, we tested our approach with different numbers of operating motor and aspect angle of a drone. The proposed method improved the accuracy from 89.3% to 94.7%. Second, two types of drone at the 50 and 100 m height are classified and showed 100% accuracy due to distinct difference in the result images.
Autors: Byung Kwan Kim;Hyun-Seong Kang;Seong-Ook Park;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 38 - 42
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: Jan 2017, volume: 16, issue:1, pages: 21 - 23
Publisher: IEEE
 
» Dual Polarized Planar Aperture Antenna on LTCC for 60-GHz Antenna-in-Package Applications
Abstract:
This paper presents a novel dual polarized planar aperture antenna using the low-temperature cofired ceramics technology to realize a novel antenna-in-package for a 60-GHz CMOS differential transceiver chip. Planar aperture antenna technology ensures high gain and wide bandwidth. Differential feeding is adopted to be compatible with the chip. Dual polarization makes the antenna function as a pair of single polarized antennas but occupies much less area. The antenna is ±45° dual polarized, and each polarization acts as either a transmitting (TX) or receiving (RX) antenna. This improves the signal-to-noise ratio of the wireless channel in a point-to-point communication, because the TX/RX polarization of one antenna is naturally copolarized with the RX/TX polarization of the other antenna. A prototype of the proposed antenna is designed, fabricated, and measured, whose size is 12 mm 12 mm mm (). The measurement shows that the −10 dB impedance bandwidth covers the entire 60 GHz unlicensed band (57–64 GHz) for both polarizations. Within the bandwidth, the isolation between the ports of the two polarizations is better than 26 dB, and the gain is higher than 10 dBi with a peak of around 12 dBi for both polarizations.
Autors: Shaowei Liao;Quan Xue;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 63 - 70
Publisher: IEEE
 
» Dual-Band Digital Predistortion Using a Single Transmitter Observation Receiver and Single Training Engine
Abstract:
This paper tackles the hardware complexity of a digital predistortion (DPD) system used to linearize a power amplifier (PA) driven with interband carrier aggregated (CA) signals (i.e., two component carriers with different modulation bandwidths and wide frequency separations). It focuses particularly on reducing the required bandwidth, and number of channels, of the transmitter’s observation receiver (TOR) as well as the specifications of the underlying building blocks (e.g., speed of the analog-to-digital converter). A novel dual-band DPD system using a single TOR was devised. The training of the DPD for each band was carried out in an alternating fashion, using a single training engine following a model-reference adaptive control approach with a recursive least squares algorithm. The proposed approach was experimentally validated by successfully linearizing a 20-W Class F Doherty PA driven with different multistandard CA signals.
Autors: Bilel Fehri;Slim Boumaiza;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 315 - 321
Publisher: IEEE
 
» Dual-Gate Charge Trap Flash Memory for Highly Reliable Triple Level Cell Using Capacitive Coupling Effects
Abstract:
In this letter, the triple level cell (TLC) NAND flash memory with excellent properties was implemented by a thin film charge trap flash memory with a dual-gate structure by using the capacitive coupling effect between the front gate and back gate. As compared with the single-gate (SG) mode operation, a large memory window at low program and erase (P/E) voltages was obtained from the dual-gate (DG) mode operation owing to the capacitive coupled self-amplifying effect. The TLC was implemented by using the DG-mode operation with highly stable eight levels: a large threshold voltage difference >9 V per level was obtained under low operating voltages at <14 V with a fast P/E speed of . In contrast, the conventional SG mode was unfavorable to TLC. Furthermore, the DG mode showed a much smaller charge loss than the SG mode, resulting in stable retention and endurance characteristics at room temperature and high temperature.
Autors: Min-Ju Ahn;Won-Ju Cho;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 36 - 39
Publisher: IEEE
 
» Dual-Tree Complex Wavelet Transform-Based Control Algorithm for Power Quality Improvement in a Distribution System
Abstract:
This paper presents a dual tree-complex wavelet transform-based control algorithm for a distribution static compensator (DSTATCOM) to improve the power quality (PQ) in a distribution system. PQ disturbances like harmonics and starting as well as ending of unbalancing in all phase load currents are also assessed simultaneously. The distorted load current of each phase is decomposed into various frequency levels with this technique to extract respective line frequency component for the estimation of the reference active power component. The deviations of respective sensed load currents from these estimated reference components are used to generate the reference currents for the control of voltage source converter used as DSTATCOM. Simulated performance of DSTATCOM is presented at varying load conditions. The proposed control algorithm is also validated experimentally on a laboratory prototype of DSTATCOM. The total harmonic distortion (THD) of supply current is obtained below 5 percent with unity power factor under different load conditions which is satisfactory as per IEEE-519 standard.
Autors: Raj Kumar;Bhim Singh;D. T. Shahani;Chinmay Jain;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 764 - 772
Publisher: IEEE
 
» Dynamic Dual-Reference Sensing Scheme for Deep Submicrometer STT-MRAM
Abstract:
As process technology downscales, read reliability has become a critical barrier for spin transfer torque magnetic random access memory (STT-MRAM), owing to the increasing process-temperature-voltage (PVT) variations, decreasing critical switching current of magnetic tunnel junction (MTJ) and supply voltage. To deal with the read reliability challenge, we propose herein a dynamic dual-reference sensing (DDRS) scheme. The key features of the proposed DDRS scheme include: (a) two reference signals, generated by two reference cells with the same structures as those of the data cells, are provided to the sensing circuit; (b) the reference signals are adaptively dynamical depending on the content stored in the target data cell; (c) two output signals are obtained to decide the sensing result, adding redundancy for supporting self-error detection (SED) capability. The proposed DDRS scheme can achieve a great improvement in sensing margin (SM) and bit error rate (BER), in comparison with conventional sensing schemes. In addition, no regularity problems exist in the proposed DDRS scheme, as the reference cells maintain exactly the same structures as those of the data cells. Our simulation results show that the proposed DDRS scheme can achieve a increase in average SM, and a ~ 70% reduction in average BER, compared with conventional sensing schemes.
Autors: Wang Kang;Tingting Pang;Weifeng Lv;Weisheng Zhao;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2017, volume: 64, issue:1, pages: 122 - 132
Publisher: IEEE
 
» Dynamic Electrical Source Imaging (DESI) of Seizures and Interictal Epileptic Discharges Without Ensemble Averaging
Abstract:
We propose an algorithm for electrical source imaging of epileptic discharges that takes a data-driven approach to regularizing the dynamics of solutions. The method is based on linear system identification on short time segments, combined with a classical inverse solution approach. Whereas ensemble averaging of segments or epochs discards inter-segment variations by averaging across them, our approach explicitly models them. Indeed, it may even be possible to avoid the need for the time-consuming process of marking epochs containing discharges altogether. We demonstrate that this approach can produce both stable and accurate inverse solutions in experiments using simulated data and real data from epilepsy patients. In an illustrative example, we show that we are able to image propagation using this approach. We show that when applied to imaging seizure data, our approach reproducibly localized frequent seizure activity to within the margins of surgeries that led to patients’ seizure freedom. The same approach could be used in the planning of epilepsy surgeries, as a way to localize potentially epileptogenic tissue that should be resected.
Autors: Burak Erem;Damon E. Hyde;Jurriaan M. Peters;Frank H. Duffy;Simon K. Warfield;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 98 - 110
Publisher: IEEE
 
» Dynamic Games With Asymmetric Information: Common Information Based Perfect Bayesian Equilibria and Sequential Decomposition
Abstract:
We formulate and analyze a general class of stochastic dynamic games with asymmetric information arising in dynamic systems. In such games, multiple strategic agents control the system dynamics and have different information about the system over time. Because of the presence of asymmetric information, each agent needs to form beliefs about other agents' private information. Therefore, the specification of the agents' beliefs along with their strategies is necessary to study the dynamic game. We use Perfect Bayesian equilibrium (PBE) as our solution concept. A PBE consists of a pair of strategy profile and belief system. In a PBE, every agent's strategy should be a best response under the belief system, and the belief system depends on agents' strategy profile when there is signaling among agents. Therefore, the circular dependence between strategy profile and belief system makes it difficult to compute PBE. Using the common information among agents, we introduce a subclass of PBE called common information based perfect Bayesian equilibria (CIB-PBE), and provide a sequential decomposition of the dynamic game. Such decomposition leads to a backward induction algorithm to compute CIB-PBE. We illustrate the sequential decomposition with an example of a multiple access broadcast game. We prove the existence of CIB-PBE for a subclass of dynamic games.
Autors: Yi Ouyang;Hamidreza Tavafoghi;Demosthenis Teneketzis;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 222 - 237
Publisher: IEEE
 
» Dynamic Manga: Animating Still Manga via Camera Movement
Abstract:
We propose a method for animating still manga imagery through camera movements. Given a series of existing manga pages, we start by automatically extracting panels, comic characters, and balloons from the manga pages. Then, we use a data-driven graphical model to infer per-panel motion and emotion states from low-level visual patterns. Finally, by combining domain knowledge of film production and characteristics of manga, we simulate camera movements over the manga pages, yielding an animation. The results augment the still manga contents with animated motion that reveals the mood and tension of the story, while maintaining the original narrative. We have tested our method on manga series of different genres, and demonstrated that our method can generate animations that are more effective in storytelling and pacing, with less human efforts, as compared with prior works. We also show two applications of our method, mobile comic reading, and comic trailer generation.
Autors: Ying Cao;Xufang Pang;Antoni B. Chan;Rynson W. H. Lau;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jan 2017, volume: 19, issue:1, pages: 160 - 172
Publisher: IEEE
 
» Dynamic Rain Attenuation Model for Millimeter Wave Network Analysis
Abstract:
In millimeter wave networks, a received signal level and interference dynamically vary due to rain attenuation. These physical layer variations have influence on upper communication layers, which yield to variable network capabilities to serve traffic demands. Standards and agreements between service providers and users usually specify performance objectives at annual level. In order to make realistic annual level performance analysis of such networks, a new computationally efficient dynamic rain attenuation model is proposed and analyzed. The model reproduces assumed rain statistics at annual level: cumulative distribution function (cdf) of rain intensity, number of rain events in which specified rain intensity threshold is exceeded, rain advection vector intensity, and rain advection vector azimuth. Derivation of model parameter tolerances is based on the experimental results from dense rain gauge network. As an example of model application, annual level cdfs of node-to-node connection capacity in a test network are calculated.
Autors: Miroslav V. Perić;Dragana B. Perić;Branislav M. Todorović;Miroslav V. Popović;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 441 - 450
Publisher: IEEE
 
» Dynamic Spectrum Management: A Complete Complexity Characterization
Abstract:
Consider a multi-user multi-carrier communication system where multiple users share multiple discrete subcarriers. To achieve high spectrum efficiency, the users in the system must choose their transmit power dynamically in response to fast channel fluctuations. Assuming perfect channel state information, two formulations for the spectrum management (power control) problem are considered in this paper: the first is to minimize the total transmission power subject to all users’ transmission data rate constraints, and the second is to maximize the min-rate utility subject to individual power constraints at each user. It is known in the literature that both formulations of the problem are polynomial time solvable when the number of subcarriers is one and strongly NP-hard when the number of subcarriers are greater than or equal to three. However, the complexity characterization of the problem when the number of subcarriers is two has been missing for a long time. This paper answers this long-standing open question: both formulations of the problem are strongly NP-hard when the number of subcarriers is two.
Autors: Ya-Feng Liu;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 392 - 403
Publisher: IEEE
 
» Dynamic Spectrum Sharing for the Coexistence of Smart Utility Networks and WLANs in Smart Grid Communications
Abstract:
A smart utility network (SUN), as defined in the IEEE 802.15.4g standard, is an emerging technology enabling reliable data transmissions in smart grid (SG) neighbourhood area networks. However, a SUN operates on unlicensed bands that are overlapped with most of the channels of wireless local area networks (WLANs). Thus, it is critical to investigate the coexistence issues for SUNs and WLANs in SG. This article aims to propose a dynamic spectrum sharing (DSS) coexistence scheme working with cognitive radio techniques, including the designs of network topology and channel detection/allocation schemes. We also establish Markov chain models based on channel state transitions for the proposed schemes, which are used to analyze network performance from the viewpoint of SUN services. The analytical results show that a channel reservation strategy is critical to ensure satisfactory performance of SUNs.
Autors: Ruofei Ma;Hsiao-Hwa Chen;Weixiao Meng;
Appeared in: IEEE Network
Publication date: Jan 2017, volume: 31, issue:1, pages: 88 - 96
Publisher: IEEE
 
» Dynamic Task Execution Using Active Parameter Identification With the Baxter Research Robot
Abstract:
This paper presents experimental results from the real-time parameter estimation of a system model and subsequent trajectory optimization for a dynamic task using the Baxter Research Robot from Rethink Robotics. An active estimator maximizing Fisher information is used in real time with a closed-loop, nonlinear control technique known as sequential action control. Baxter is tasked with estimating the length of a string connected to a load suspended from the gripper with a load cell providing the single source of feedback to the estimator. Following the active estimation, a trajectory is generated using the trep software package that controls Baxter to dynamically swing a suspended load into a box. Several trials are presented with varying initial estimates showing that the estimation is required to obtain adequate open-loop trajectories to complete the prescribed task. The result of one trial with and without the active estimation is also shown in the accompanying video.
Autors: Andrew D. Wilson;Jarvis A. Schultz;Alex R. Ansari;Todd D. Murphey;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 391 - 397
Publisher: IEEE
 
» E-Including the Illiterate
Abstract:
In present-day society, we communicate over the Internet in several media forms. We put videos and images online, listen to music made by famous bands or by our friends, and read and write a lot of text. Never in the history of mankind have we produced more text than at this present moment, so being able to read and write is an important way of taking part in our society. We tend to forget that, even in our educated communities, not all people can read or write and there exist several degrees of literateness. People with reduced cognitive capacities and those migrating from cultures with a different language, or even a completely different writing system, are excluded from fully taking part in written online communication: they are e-excluded.
Autors: Vincent Vandeghinste;Leen Sevens;Ineke Schuurman;
Appeared in: IEEE Potentials
Publication date: Jan 2017, volume: 36, issue:1, pages: 29 - 33
Publisher: IEEE
 
» EBSCam: Background Subtraction for Ubiquitous Computing
Abstract:
Background subtraction (BS) is a crucial machine vision scheme for detecting moving objects in a scene. With the advent of smart cameras, the embedded implementation of BS finds ever-increasing applications. This paper presents a new BS scheme called efficient BS for smart cameras (EBSCam). EBSCam thresholds the change in the estimated background model, which suppresses variance of the estimates, resulting in competitive performance compared with standard BS schemes. The percentage of wrong classification of EBSCam is lower than those of the Gaussian mixture model (GMM) (10.97%) and the pixel-based adaptive segmenter (PBAS) (4.66%) algorithms in FPGA implementations. Moreover, the memory bandwidth requirement of EBSCam is 6.66%, 41.36%, and 90.48% lower than the state-of-the-art FPGA implementation of GMM, ViBe, and PBAS algorithms, respectively. EBSCam achieves a significant speed up compared with the FPGA implementations of GMM (by 43.3%), ViBe (by 118.6%), and PBAS (by 144.8%) schemes. Similarly, the energy consumption of EBSCam is 80.56% and 99.9% less compared with GMM and PBAS, respectively. In summary, the advantages of EBSCam in accuracy, speed, and energy consumption combined together make it especially suitable for embedded applications.
Autors: Muhammad Umar Karim Khan;Asim Khan;Chong-Min Kyung;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 35 - 47
Publisher: IEEE
 
» Echo State Networks for Self-Organizing Resource Allocation in LTE-U With Uplink–Downlink Decoupling
Abstract:
Uplink–downlink decoupling in which users can be associated to different base stations in the uplink and downlink of heterogeneous small cell networks (SCNs) has attracted significant attention recently. However, most existing works focus on simple association mechanisms in LTE SCNs that operate only in the licensed band. In contrast, in this paper, the problem of resource allocation with uplink–downlink decoupling is studied for an SCN that incorporates LTE in the unlicensed band. Here, the users can access both licensed and unlicensed bands while being associated to different base stations. This problem is formulated as a noncooperative game that incorporates user association, spectrum allocation, and load balancing. To solve this problem, a distributed algorithm based on the machine learning framework of echo state networks (ESNs) is proposed. This proposed algorithm allows the small base stations to autonomously choose their optimal resource allocation strategies given only limited information on the network’s and users’ states. It is shown that the proposed algorithm converges to a stationary mixed-strategy distribution, which constitutes a mixed strategy Nash equilibrium for their studied game. Simulation results show that the proposed approach yields significant gain, in terms of the sum-rate of the 50th percentile of users, that reaches up to 167% compared with a Q-learning algorithm. The results also show that the ESN significantly provides a considerable reduction of information exchange for the wireless network.
Autors: Mingzhe Chen;Walid Saad;Changchuan Yin;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 3 - 16
Publisher: IEEE
 
» Edge Preserving and Noise Reducing Reconstruction for Magnetic Particle Imaging
Abstract:
Magnetic particle imaging (MPI) is an emerging medical imaging modality which is based on the non-linear response of magnetic nanoparticles to an applied magnetic field. It is an important feature of MPI that even fast dynamic processes can be captured for 3D volumes. The high temporal resolution in turn leads to large amounts of data which have to be handled efficiently. But as the system matrix of MPI is non-sparse, the image reconstruction gets computationally demanding. Therefore, currently only basic image reconstruction methods such as Tikhonov regularization are used. However, Tikhonov regularization is known to oversmooth edges in the reconstructed image and to have only a limited noise reducing effect. In this work, we develop an efficient edge preserving and noise reducing reconstruction method for MPI. As regularization model, we propose to use the nonnegative fused lasso model, and we devise a discretization that is adapted to the acquisition geometry of the preclinical MPI scanner considered in this work. We develop a customized solver based on a generalized forward-backward scheme which is particularly suitable for the dense and not well-structured system matrices in MPI. Already a non-optimized prototype implementation processes a 3D volume within a few seconds so that processing several frames per second seems amenable. We demonstrate the improvement in reconstruction quality over the state-of-the-art method in an experimental medical setup for an in-vitro angioplasty of a stenosis.
Autors: Martin Storath;Christina Brandt;Martin Hofmann;Tobias Knopp;Johannes Salamon;Alexander Weber;Andreas Weinmann;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 74 - 85
Publisher: IEEE
 
» Edge-Aware Label Propagation for Mobile Facial Enhancement on the Cloud
Abstract:
This paper proposes a facial enhancement framework with mask generation for cloud-based mobile applications. We mathematically analyze and unify the mask generation, as well as the state-of-the-art region-aware mask and edit propagation techniques, from a graph-based semisupervised learning perspective. Then we propose a label propagation model with a new edge-aware structure and guided feature for mask generation. The limit analysis of the model leads to a fast algorithm, which reduces the intrinsic computation cost. Then we develop a flexible and efficient cloud-based PaaS system, called FaceMore, for intelligent mobile face enhancement. The flexibility and extendibility of the cloud-based architecture facilitates intelligent facial enhancement applications and the parallel processing effectively improves the efficiency of the algorithm. Qualitative and quantitative evaluations were performed for mask propagation and face enhancement. Comparisons with the previous methods and five representative commercial systems, including PicTreat, Portraiture, Portrait+, Meitu, and Baidu Motu, illustrate the robustness and effectiveness of our method.
Autors: Lingyu Liang;Lianwen Jin;Deng Liu;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jan 2017, volume: 27, issue:1, pages: 125 - 138
Publisher: IEEE
 
» Editor's Note
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: David A. Bader;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 1 - 1
Publisher: IEEE
 
» Editorial
Abstract:
Presents the editorial for this issue of the publication.
Autors: Jian Pei;Xuemin Lin;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jan 2017, volume: 29, issue:1, pages: 1 - 1
Publisher: IEEE
 
» Editorial to the regular issue
Abstract:
This is the 1st issue of the IEEE Latin America Transactions of the year 2017. Volume 15 Issue 1, January 2017
Autors: Mirela Sechi Moretti Annoni Notare;
Appeared in: IEEE Latin America Transactions
Publication date: Jan 2017, volume: 15, issue:1, pages: 3 - 12
Publisher: IEEE
 
» Effect of Active Layer Thickness on Device Performance of Tungsten-Doped InZnO Thin-Film Transistor
Abstract:
Tungsten ( at. %)-doped InZnO thin-film transistors were fabricated as a function of the active layer thickness using an RF sputtering system. To explain the degradation of the device performance in relation to the changes of the active layer thickness, the correlations between the device performance and the physical properties, including the film density, surface/interface roughness, band edge state below the conduction band, refractive index, and composition along the depth direction were investigated. Tungsten-doped indium–zinc oxide (WIZO) TFTs with active layer thickness of 10 nm exhibited the highest field effect mobility of 19.57 cm2/Vs and the lowest threshold voltage shift of 0.62 V. The enhancement of the device performance is strongly correlated with the highest film density and a flat interface roughness of SiO2–WIZO. In addition, interface layer thickness and band edge states below the conduction band were changed with increasing active layer thickness. These remarkable changes in the interface layer thickness and band edge state could be correlated to changes in the device performance.
Autors: Hyun-Woo Park;Kyung Park;Jang-Yeon Kwon;Dukhyun Choi;Kwun-Bum Chung;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 159 - 163
Publisher: IEEE
 
» Effect of Copper Substitution on Fe3O4 Particles Prepared via Coprecipitation and Flux Methods
Abstract:
We investigated the effect of copper substitution on the magnetic and physical properties of Fe3O4 prepared by coprecipitation and flux methods. The coprecipitation compositions were chosen according to the formula (Cux2+Fe1–x2+) Fe23+O4, where varied between 0 and 1. We found that the flux treatment method is ideal for growing large particles of sub-micrometer size. The size of the final particles obtained was in the range of 200–1500 nm, and the size decreased with increasing copper content. Cubic spinel structured CuxFe3–xO4 particles were obtained by conducting hydrogen gas reduction process at 380 °C–530 °C for 1–2 h after flux treatment. From x-ray diffraction patterns, all particles were determined to be cubic spinel without any sign of the tetragonal structure expected from the Jahn–Teller effect. For these cubic spinel particles, saturation magnetization was controlled at 25–86 Am2/kg, and the value decreased linearly with increasing copper content. The coercive force remained almost constant at 13.7–19.1 kA/m, independent of the copper content.
Autors: Hawa Latiff;Mikio Kishimoto;Sonia Sharmin;Eiji Kita;Hideto Yanagihara;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 4
Publisher: IEEE
 
» Effect of Temperature and Stress on Residual Magnetic Signals in Ferromagnetic Structural Steel
Abstract:
Although we know that stress in ferromagnetic steels can induce magnetic signals on the surface, temperature could be another critical factor to impact the signals of the steels used under high temperature conditions. To better understand the mechanism of the residual magnetic signals, a modified Jiles–Atherton (J-A) model based on thermal and mechanical effects was developed. In the experiment, ferromagnetic structural steel Q345B was tested under static tensile stress, and the variation of magnetic signal normal component and its mean value were investigated during the tests. Experimental results showed that the mean value decreased with the increase in temperature, however, increased with the increase in tensile stress. The microstructures were observed at the location of fracture and it was found that the size of inclusions increased with the increase in temperature, which blocked the irreversible movement of magnetic domains and leaded to the decrease of magnetic signals. The experimental results were consistent with the theoretical analysis, which indicated that the variation of effective field calculated based on the modified J-A model was similar to the mean value in the tests.
Autors: Haihong Huang;Zhengchun Qian;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 8
Publisher: IEEE
 
» Effective 3-D Device Electrothermal Simulation Analysis of Influence of Metallization Geometry on Multifinger Power HEMTs Properties
Abstract:
In this brief, obtained results of the electrothermal analysis of multifinger power high-electron mobility transistors (HEMTs) are presented. The analysis of thermal and electrical behavior is supported by effective 3-D electrothermal device simulation method developed for Synopsys TCAD Sentaurus environment using mixed-mode setup. The effects of multifinger HEMT structure metallization layout design are described and studied. Simulation results depict the significant effect of metallization geometry on the electrothermal properties and behavior of the power multifinger HEMTs.
Autors: Aleš Chvála;Juraj Marek;Patrik Príbytný;Alexander Šatka;Martin Donoval;Daniel Donoval;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 333 - 336
Publisher: IEEE
 
» Effects of Intensity Noise in Digital Demodulation for Fiber Laser Sensor
Abstract:
Hydrophone array-based distributed feedback fiber laser (DFB FL) has a small size and large sensitivity; however, it also suffers from intensity noise completely. In this letter, a transfer function for intensity noise propagation through the use of a DFB FL sensor interrogation system is derived, basing on which a symmetric algorithm using coupler is improved. Both experimental and simulation data are provided to validate the model. A noise reduction of 20 dB is achieved.
Autors: Xin Mao;Jun Bin Huang;Hong Can Gu;Bo Tang;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:2, pages: 247 - 250
Publisher: IEEE
 
» Effects of MgxZn1-xO Thickness on the Bandwidth of Metal–Semiconductor–Metal Bandpass Photodetectors
Abstract:
A metal–semiconductor–metal photodetector (PD) whose detection wavelength can be modulated was fabricated using a MgxZn1-xO/ZnO bilayer. By varying the MgxZn1-xO layer thickness (50–400 nm), we modulated the detection wavelength from lowpass to bandpass. For a thin (50 nm) MgxZn1-xO film, most short-wavelength (less than 340 nm) incident photons—more than 69%—passed through the MgxZn1-xO and were absorbed by ZnO, causing a higher photoresponse in the short-wavelength region and thus a low-pass PD. As the thickness of the MgxZn1-xO film increased, the short-wavelength photoresponse was gradually suppressed, and a bandpass PD was achieved. A thicker (400 nm) MgxZn1-xO film absorbed more short-wavelength (less than 340 nm) incident photons, leaving only 5.5% of the incident photons to be absorbed by the ZnO layer underneath. This reduced the short-wavelength photoresponse, yielding a bandpass PD with a detection wavelength of 325–360 nm. Although the short-wavelength (less than 340 nm) incident photons were absorbed by MgxZn1-xO, few photogenerated electron–hole pairs contributed to the photoresponse; instead, they were trapped by the defects in MgxZn1-xO because of its poor crystalline quality.
Autors: Jun-Dar Hwang;Guan-Syun Lin;Sheng-Beng Hwang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 195 - 199
Publisher: IEEE
 
» Effects of Nonuniform Magnetic Fields on the “Magnetic Window” in Blackout Mitigation
Abstract:
The “magnetic window” is considered a promising means to eliminate reentry communications blackout. Nevertheless, a numerical analysis is needed detailing the efficacy of the window under nonuniform magnetic fields generated by a magnet. For this purpose, the electromagnetic wave transmission characteristics are obtained using the hybrid matrix method. A two-Gaussian model for the plasma sheath density is assumed. The sheath is modeled by partitioning into slabs, for which the magnetic field and electron density in each slab are assumed uniform. Various plasma parameter values and magnetic field strengths are used. The numerical results show that, compared with uniform magnetic fields, a wider stopband in the transmission response is formed using nonuniform magnetic fields; the stopband width depends on the range between the maximum and the minimum magnetic field strengths. Therefore, the frequency hoped for in the magnetic window in the left passband using uniform magnetic field may be located in the stopband arising from the nonuniform magnetic field.
Autors: Hui Zhou;Xiaoping Li;Yanming Liu;Bowen Bai;Kai Xie;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 15 - 23
Publisher: IEEE
 
» Efficiency and Stability of Pulse Compression Using SBS in a Fiber With Frequency-Shifted Loopback
Abstract:
Efficient pulse compression using stimulated Brillouin scattering in a fiber is proposed where the pump pulse transmitted through the fiber is immediately loopbacked to the fiber with its frequency downshifted by the amount equal to the Brillouin frequency shift of the fiber. The effect of the steepness of the front edge of the pump pulse on the compression performance and the influence of the spontaneous Brillouin scattering on the stability of the compressed pulses are numerically studied. A preliminary experiment of the proposed scheme is also reported.
Autors: Masayuki Matsumoto;Genya Miyashita;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 3 - 6
Publisher: IEEE
 
» Efficient 3D Resource Management for Spectrum Aggregation in Cellular Networks
Abstract:
As the mobile communication technologies evolving, spectrum resource has become extremely scarce. Accordingly, spectrum aggregation (SA) is proposed as an emerging solution to efficiently utilize the dispersive resource. To address such a challenging issue, this paper introduces power domain into the conventional SA which only works in the time and frequency domains, and extends the resource block (RB), which is a time-frequency spectrum management unit in LTE standard, to a time-frequency-power spectrum unit termed resource cube. Based on this, a novel radio resource management (RRM) scheme is proposed to manage the spectrum with multiplexing division in time, frequency, and power domains (3D) simultaneously. Through theoretical derivations, we show that under certain simplifications, the proposed 3D RRM could be formulated as a convex objective function with linear constrains, and can be solved with low computational complexity. When compared with the conventional RB-based RRM, the proposed 3D RRM matches the real-time requirement in SA. Furthermore, it is proved that the proposed scheme could achieve better energy efficiency than the RB-based ones.
Autors: Weijia Han;Chuan Huang;Jiandong Li;Xiao Ma;Liang Wang;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2017, volume: 35, issue:1, pages: 106 - 117
Publisher: IEEE
 
» Efficient and Precise Dynamic Initialization of Induction Motors Using Unified Newton–Raphson Power-Flow Approach
Abstract:
An accurate initialization is very important for power-system dynamic simulations. Using conventional power-flow model to initialize induction motors is not straightforward because an unavoidable mismatch between pre-specified reactive powers from power-flow calculation and the ones, actually required by motors. To overcome this problem, this paper presents a unified method for incorporating a nonlinear model of induction motors into Newton–Raphson (NR) power-flow algorithm, allowing precise steady-state solutions of power networks with induction motors to be solved simultaneously. The power-flow results of the extended algorithm are then compared with benchmark results for model verification. The ability of the extended algorithm is also demonstrated using IEEE-30 bus and 118 bus test systems with large groups of induction motor loads. The studied results indicate that the presented algorithm not only gives exact steady-state initialization without existence of the reactive power mismatches but also preserves powerful Newton–Raphson's quadratic convergence characteristics.
Autors: P. Aree;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 464 - 473
Publisher: IEEE
 
» Efficient and Privacy-Preserving Min and $k$ th Min Computations in Mobile Sensing Systems
Abstract:
Protecting the privacy of mobile phone user participants is extremely important for mobile phone sensing applications. In this paper, we study how an aggregator can expeditiously compute the minimum value or the th minimum value of all users’ data without knowing them. We construct two secure protocols using probabilistic coding schemes and a cipher system that allows homomorphic bitwise XOR computations for our problems. Following the standard cryptographic security definition in the semi-honest model, we formally prove our protocols’ security. The protocols proposed by us can support time-series data and need not to assume the aggregator is trusted. Moreover, different from existing protocols that are based on secure arithmetic sum computations, our protocols are based on secure bitwise XOR computations, thus are more efficient.
Autors: Yuan Zhang;Qingjun Chen;Sheng Zhong;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Jan 2017, volume: 14, issue:1, pages: 9 - 21
Publisher: IEEE
 
» Efficient Channel Estimation for Reconfigurable MIMO Antennas: Training Techniques and Performance Analysis
Abstract:
Multifunctional and reconfigurable multiple-input multiple-output (MR-MIMO) antennas are capable of dynamically changing the operation frequencies, polarizations, and radiation patterns, and can remarkably enhance system capabilities. However, in coherent communication systems, using MR-MIMO antennas with a large number of operational modes may incur prohibitive complexity due to the need for channel state estimation for each mode. To address this issue, we derive an explicit relation among the radiation patterns for the antenna modes and the resulting channel gains. We propose a joint channel estimation/prediction scheme where only a subset of all the antenna modes is trained for estimation, and then, the channels associated with the modes that are not trained are predicted using the correlations among the different antenna modes. We propose various training mechanisms with reduced overhead and improved estimation performance, and study the impact of channel estimation error and training overhead on the MR-MIMO system performance. We demonstrate that one can achieve significantly improved data rates and lower error probabilities utilizing the proposed approaches. For instance, under practical settings, we observe about 25% throughput increase or about 3-dB signal-to-noise ratio improvement under the same training overhead with respect to non-reconfigurable antenna systems.
Autors: Israfil Bahceci;Mehedi Hasan;Tolga M. Duman;Bedri A. Cetiner;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 565 - 580
Publisher: IEEE
 
» Efficient Designs of Multiported Memory on FPGA
Abstract:
The utilization of block RAMs (BRAMs) is a critical performance factor for multiported memory designs on field-programmable gate arrays (FPGAs). Not only does the excessive demand on BRAMs block the usage of BRAMs from other parts of a design, but the complex routing between BRAMs and logic also limits the operating frequency. This paper first introduces a brand new perspective and a more efficient way of using a conventional two reads one write (2R1W) memory as a 2R1W/4R memory. By exploiting the 2R1W/4R as the building block, this paper introduces a hierarchical design of 4R1W memory that requires 25% fewer BRAMs than the previous approach of duplicating the 2R1W module. Memories with more read/write ports can be extended from the proposed 2R1W/4R memory and the hierarchical 4R1W memory. Compared with previous xor-based and live value table-based approaches, the proposed designs can, respectively, reduce up to 53% and 69% of BRAM usage for 4R2W memory designs with 8K-depth. For complex multiported designs, the proposed BRAM-efficient approaches can achieve higher clock frequencies by alleviating the complex routing in an FPGA. For 4R3W memory with 8K-depth, the proposed design can save 53% of BRAMs and enhance the operating frequency by 20%.
Autors: Bo-Cheng Charles Lai;Jiun-Liang Lin;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 139 - 150
Publisher: IEEE
 
» Efficient Energy Management for the Internet of Things in Smart Cities
Abstract:
The drastic increase in urbanization over the past few years requires sustainable, efficient, and smart solutions for transportation, governance, environment, quality of life, and so on. The Internet of Things offers many sophisticated and ubiquitous applications for smart cities. The energy demand of IoT applications is increased, while IoT devices continue to grow in both numbers and requirements. Therefore, smart city solutions must have the ability to efficiently utilize energy and handle the associated challenges. Energy management is considered as a key paradigm for the realization of complex energy systems in smart cities. In this article, we present a brief overview of energy management and challenges in smart cities. We then provide a unifying framework for energy-efficient optimization and scheduling of IoT-based smart cities. We also discuss the energy harvesting in smart cities, which is a promising solution for extending the lifetime of low-power devices and its related challenges. We detail two case studies. The first one targets energy-efficient scheduling in smart homes, and the second covers wireless power transfer for IoT devices in smart cities. Simulation results for the case studies demonstrate the tremendous impact of energy- efficient scheduling optimization and wireless power transfer on the performance of IoT in smart cities.
Autors: Waleed Ejaz;Muhammad Naeem;Adnan Shahid;Alagan Anpalagan;Minho Jo;
Appeared in: IEEE Communications Magazine
Publication date: Jan 2017, volume: 55, issue:1, pages: 84 - 91
Publisher: IEEE
 
» Efficient Feasibility Determination With Multiple Performance Measure Constraints
Abstract:
Feasibility determination has emerged as a widely applied problem in simulation optimization. It seeks to provide all the feasible designs from a finite set of design alternatives based on which the final decision can be chosen by the decision maker. In this paper, we consider the feasibility determination problem in presence of multiple performance measure constraints. The optimal solution to maximize the probability of correct feasibility determination is derived under asymptotic approximation. A corresponding sequential selection procedure is designed for implementation. The numerical testing shows that our approach can enhance the simulation efficiency significantly.
Autors: Siyang Gao;Weiwei Chen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 113 - 122
Publisher: IEEE
 
» Efficient Media Streaming with Collaborative Terminals for the Smart City Environment
Abstract:
Among multiple services delivered over future mobile networks, the most demanding (from the required bandwidth point of view) are related to media streaming, which is a key component in smart applications (entertainment, tourism, surveillance, etc.). Such applications have to exploit a considerable amount of data, which is difficult to achieve especially in dense urban environments. In this context, the article presents a new solution for HTTP-compliant adaptive media streaming applicable to future 5G mobile networks, aimed at increasing bandwidth availability through the use of multiple radio access technologies and direct connections between devices if they are in proximity of each other. The proposed solution considers a scenario in which a high-quality media stream is received by multipath transmission through the radio access network. Collaboration of neighboring devices is exploited by using direct device-to-device links. Thus, proxy nodes can be inserted between a given media receiver and an access network. Toward ensuring optimized resource allocation at both levels, base station-to-device and device-to-device, this article introduces the architectural modules required for collaboration streaming inside the radio access network and end user’s device, and proposes enhancements in HTTP-compliant adaptive streaming protocols in order to become suitable for a multipath collaborative scenario.
Autors: Jordi Mongay Batalla;Piotr Krawiec;Constandinos X. Mavromoustakis;George Mastorakis;Naveen Chilamkurti;Daniel Negru;Joachim Bruneau-Queyreix;Eugen Borcoci;
Appeared in: IEEE Communications Magazine
Publication date: Jan 2017, volume: 55, issue:1, pages: 98 - 104
Publisher: IEEE
 
» Efficient Physical-Layer Unknown Tag Identification in Large-scale RFID Systems
Abstract:
Radio frequency identification (RFID) is an automatic identification technology that brings a revolutionary change to quickly identify tagged objects from the collected tag IDs. Considering the misplaced and newly added tags, fast identifying such unknown tags is of paramount importance, especially in large-scale RFID systems. Existing solutions can either identify all unknown tags with low time-efficiency, or identify most unknown tags quickly by sacrificing the identification accuracy. Unlike existing work, this paper proposes a protocol that utilizes physical layer (PHY) information to identify the intact unknown tag set with high efficiency. We exploit the physical signals in collision slots to separate unknown tags from known tags, a new technique to speed up the ID collection. Such new technique was verified in an RFID prototype system using the USRP-based reader and WISP tags. We also evaluated our protocol to show the efficiency of leveraging PHY signals to successfully get all unknown tag IDs without wasted known tag ID transmission. Simulation results show that our protocols outperform prior unknown tag identification protocols. For example, given 1000 unknown tags and 10 000 known tags, our best protocol has 56.8% less time to the state-of-the-art protocol when collecting all unknown tag IDs.
Autors: Feng Zhu;Bin Xiao;Jia Liu;Li-jun Chen;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 283 - 295
Publisher: IEEE
 
» Efficient Sensitivity Analysis for Inequality Queries in Probabilistic Databases
Abstract:
In this paper, we study inequality query (IQ query) processing in tuple independent probabilistic databases, where IQ queries can be categorized into IQ-path, IQ-tree, and IQ-graph queries. We focus on two related issues for IQ queries. One issue is to efficiently compute their probabilities, with the observation that the time complexity of the state-of-the-art algorithm to process IQ-graph queries is high. The other issue is to efficiently perform their sensitivity analysis, which has not been studied before. Here, sensitivity analysis is to identify input tuples that have high influence on the probability of an answer tuple, and the influence of an input tuple is defined as the difference between the output probabilities obtained in two cases, where we assume that the tuple exists in one case and does not exist in the other one. In this paper, we compile the inequality conditions of an IQ query into a compilation tree , which encodes the Shannon expansion order. Moreover, we split into a set of subqueries and each contains only one inequality condition. Using compilation tree and decomposition, we introduce a dynamic programming algorithm called to process an IQ query in time O(|\Phi |) , where is the lineage of . An IQ query can be processed by our if and only if its inequality conditions can be compiled into a compilation tree and the inequality conditions from any node to all of its child nodes must be the same in . We conduct extensive experiments using real and synthetic datasets to demonstrate the efficiency of our algorithm for computing the probabilities and influences of IQ queries.
Autors: Biao Qin;Jeffrey Xu Yu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jan 2017, volume: 29, issue:1, pages: 86 - 99
Publisher: IEEE
 
» Efficient Soft Cancelation Decoder Architectures for Polar Codes
Abstract:
The flooding belief propagation (FO-BP) and the soft-cancelation (SCAN) algorithms are the two most popular soft-output BP algorithms for the decoding of capacity-achieving polar codes. The FO-BP algorithm has high throughput at the cost of performance degradation in high signal-to-noise ratio (SNR) region or with large block length. The SCAN algorithm has much better decoding performance while suffering from long decoding latency and low throughput. In this paper, an improved BP algorithm, named reduced complexity soft-cancelation (RCSC) algorithm, is proposed. Compared with the SCAN algorithm, the number of memory entries required by the RCSC algorithm is reduced by more than 50% in general, while achieving comparable or even better (e.g., when block size ) decoding performance. When block size is large (e.g., ), the proposed RCSC algorithm reduces the required memory entries by more than 23% compared with the state-of-the-art FO-BP algorithm. The numerical results show that the error performance improvement of the RCSC algorithm is more significant when the SNR increases. For a different tradeoff, a reduced latency soft-cancelation (RLSC) algorithm is proposed to reduce the decoding latency and increase the throughput of the RCSC algorithm while slightly sacrificing decoding performance. Finally, the optimized VLSI architectures are presented for the RCSC and RLSC algorithms, respectively. The synthesis results demonstrate the efficiency of the proposed algorithms and architectures.
Autors: Jun Lin;Zhiyuan Yan;Zhongfeng Wang;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 87 - 99
Publisher: IEEE
 
» Eigenfrequencies and Modal Analysis of Uniaxial, Biaxial, and Gyroelectric Spherical Cavities
Abstract:
The normalized eigenfrequencies in spherical cavities filled with uniaxial, biaxial, and gyroelectric medium are calculated, and the corresponding modal analysis is performed. A discrete eigenfunction approach is employed that permits the direct calculation of the normalized eigenfrequencies. First, a discrete basis that depends on the tensorial permittivity elements is constructed for expansion of the unknown electric field inside the cavity. Then, the boundary condition is applied on the perfect electric conductor at the cavity’s surface, which leads to two infinite sets of homogeneous equations. It is found that the uniaxial/biaxial cavities maintain quasi-TMr, quasi-TEr, as well as hybrid modes, but when the medium becomes gyroelectric, the modes are purely hybrid. The proposed approach is validated against other eigenmode solvers, up to the biaxial anisotropy. The normalized eigenfrequencies of uniaxial, biaxial, and gyroelectric filled cavities are presented and the corresponding eigenmodes are discussed.
Autors: Grigorios P. Zouros;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 20 - 27
Publisher: IEEE
 
» Elder Tracking and Fall Detection System Using Smart Tiles
Abstract:
Fall detection for elderly and patient is a very important service that has the potential of increasing autonomy of elders while minimizing the risks of living alone. It has been an active research topic due to the fact that health care industry has a big demand for products and technology of fall detection systems. Owing to the recent rapid advancement in sensing and wireless communication technologies, fall detection systems have become possible. They allow detecting fall events for the elderly, monitoring them, and consequently providing necessary help whenever needed. This paper describes the ongoing work of detecting falls in independent living senior apartments using force sensors and three-axis accelerometers concealed under intelligent tiles. The force sensors permit detecting elders’ falls, locating, tracking, and recognizing human activities (walking, standing, sitting, lying down, falling, and the transitions between them). However, the detection accuracy on real data contains false alarms coming from falling and lying postures. To solve this issue, we propose the fusion between the force sensor measurements and the accelerometer sensor decisions. As a consequence, the system accuracy is satisfactory, and the results show that the proposed methods are efficient, and they can be easily used in a real elder tracking and fall detection system.
Autors: Mohamad Daher;Ahmad Diab;Maan El Badaoui El Najjar;Mohamad Ali Khalil;François Charpillet;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 469 - 479
Publisher: IEEE
 
» Electric Arc in Low-Voltage Circuit Breakers: Experiments and Simulation
Abstract:
The aim of this paper is to present a further approach for analyzing the air electric arc in low-voltage circuit breakers (LVCBs). In order to achieve that, a new simulation model and experimental tests have been carried out. The simulation model has been designed using ANSYS CFX, a finite-volume method commercial software. This model has been defined as a 3-D geometry, with a high density structured hexahedral mesh, P1 radiation model and hot air characteristics for thermal plasma properties and transport coefficients. The model is applied to simulate the behavior of an LVCB for 50, 100, and 200 A with different numbers of splitter plates in the arc chamber and different locations for the arc ignition. As result, arc elongation and arc voltage increase have been observed when increasing the splitter plates number. Also faster arcs for higher ignition zones and greater expansion and diffusion for higher input currents have been obtained. These simulation results have been verified and validated. The verification process has been accomplished calculating the numerical errors, by means of the grid convergence index and Courant-Friedrichs–Lewis number. Thus, the most accurate mesh densities, time steps, and radiation models have been selected. Finally, the validation process has been achieved performing real experimental tests in the laboratory, proving that the results of the simulation model are close to real scenarios.
Autors: Araitz Iturregi;Bogdan Barbu;Esther Torres;Frank Berger;Inmaculada Zamora;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 113 - 120
Publisher: IEEE
 
» Electric Field Induced Nitride Trapped Charge Lateral Migration in a SONOS Flash Memory
Abstract:
We investigated electric field-induced trapped electron lateral migration in a SONOS flash cell. The threshold voltage shift () and gate-induced drain leakage (GIDL) current were measured to monitor nitride electron movement in retention. We applied different voltages to the gate and the source/drain in retention to vary the vertical and lateral electric fields. Our study shows that: 1) GIDL current can be used to monitor trapped charge lateral migration and 2) nitride charge lateral migration exhibits strong dependence on the lateral electric field. Based on measured temperature and field dependence, a nitride trapped charge emission process via thermally assisted tunneling is proposed for electron lateral migration. The emission rates of thermally assisted tunneling, direct trap-to-band tunneling and Frenkel–Poole emission were compared.
Autors: Yu-Heng Liu;Cheng-Min Jiang;Wei-Chun Chen;Tahui Wang;Wen-Jer Tsai;Tao-Cheng Lu;Kuang-Chao Chen;Chih-Yuan Lu;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 48 - 51
Publisher: IEEE
 
» Electric fields fight deadly brain tumors [News]
Abstract:
Jessica Morris was on a hiking trail in upstate New York last January when she suddenly uttered a line of gibberish and fell to the ground, her body shaking in a full seizure. A few hours later in a hospital she learned that she had glioblastoma, an aggressive brain tumor, and several days after that she was on the operating table having brain surgery. Since then, she’s been fighting for her life.
Autors: Eliza Strickland;
Appeared in: IEEE Spectrum
Publication date: Jan 2017, volume: 54, issue:1, pages: 11 - 13
Publisher: IEEE
 
» Electric Vehicle Charging Station Placement for Urban Public Bus Systems
Abstract:
Due to the low pollution and sustainable properties, using electric buses for public transportation systems has attracted considerable attention, whereas how to recharge the electric buses with long continuous service hours remains an open problem. In this paper, we consider the problem of placing electric vehicle (EV) charging stations at selected bus stops, to minimize the total installation cost of charging stations. Specifically, we study two EV charging station placement cases, with and without considering the limited battery size, which are called ECSP_LB and ECSP problems, respectively. The solution of the ECSP problem achieves the lower bound compared with the solution of the ECSP_LB problem, and the larger the battery size of the EV, the lower the overall cost of the charging station installation. For both cases, we prove that the placement problems under consideration are NP-hard and formulate them into integer linear programming. Specifically, for the ECSP problem we design a linear programming relaxation algorithm to get a suboptimal solution and derive an approximation ratio of the algorithm. Moreover, we derive the condition of the battery size when the ECSP problem can be applied. For the ECSP_LB problem, we show that, for a single bus route, the problem can be optimally solved with a backtracking algorithm, whereas for multiple bus routes we propose two heuristic algorithms, namely, multiple backtracking and greedy algorithms. Finally, simulation results show the effectiveness of the proposed schemes.
Autors: Xiumin Wang;Chau Yuen;Naveed Ul Hassan;Ning An;Weiwei Wu;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2017, volume: 18, issue:1, pages: 128 - 139
Publisher: IEEE
 
» Electrical and Ultraviolet-A Detection Properties of E-Beam Evaporated n-TiO2 Capped p-Si Nanowires Heterojunction Photodiodes
Abstract:
Fabrication and Ultraviolet (UV) detection properties of p-Si Nanowires (NWs)/n-TiO2 thin film based heterojunction photodiodes have been reported in this paper. The highly oriented, uniform and vertically aligned p-type single crystalline silicon nanowire (SiNW) arrays have been synthesized by the two step process of Electroless Metal Deposition and Etching (EMDE) technique. A thin layer (~120nm) of anatase phase titanium dioxide (TiO2) is then deposited on the top of p-SiNWs using Electron-Beam Evaporation (EBE) technique. The surface morphology and crystallinity of p-SiNWs and n-TiO2 capped SiNWs have been characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray diffraction (XRD) techniques. The optical properties of the as-deposited n-TiO2 thin film grown on p-SiNWs were analyzed using the Photoluminescence (PL) measurements. The UV detection properties of the p-SiNWs/n-TiO2 heterojunction was studied by measuring the room temperature current-voltage I  V  characteristics under dark and UV illumination conditions with incident optical power   Popt ≈ 650 μW at wavelength  ≈ 365 nm. The as-fabricated p-SiNWs/n-TiO2 thin film heterojunction photodiode showed an excellent value of Detectivity ~ 8.66×1011 mHz1/2W-1 with the External Quantum Efficiency (EQE) ~ 79.33%, Responsivity ~ 0.234 A/W and Contrast ratio ~ 113.82 at -11 V bias. Other parameters such as Rectification ratio (~ 519.82), Turn-on voltage (~0.732V) and Effective barrier height (~0.7924eV) under dark condition were also calculated. The proposed p-SiNWs)/n-TiO2 thin film hetrojunction can thus be explored for UV-A detection.
Autors: Gopal Rawat;Divya Somvanshi;Yogesh Kumar;Hemant Kumar;Chandan Kumar;Satyabrata Jit;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 49 - 57
Publisher: IEEE
 
» Electrical Thermo-Optic Tuning of Whispering Gallery Mode Microtube Resonator
Abstract:
We demonstrate a very simple electrically assisted technique for broad-range tuning of whispering gallery modes in microtube resonator, which is fabricated by embedding a FeCrAl heating wire with small resistance into a tapered silica microtube. The huge Joule heat generated by the heating wire can be effectively and thermally conducted to the microtube and consequently changes the path of the optical whispering gallery modes due to the thermo-optic effect. Experimental results show that such a device has a tuning range of 0.57 nm with excellent stability under the applied current of 200 mA, fast response (<100 ms), and low power consumption (~0.1 mW). This makes it to have potentials in tunable filters or fast optical switches.
Autors: Dongmei Huang;Wei Huang;Jing Zeng;Ming Deng;Leilei Shi;Tao Zhu;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 169 - 172
Publisher: IEEE
 
» Electrolyte-Gated FETs Based on Oxide Semiconductors: Fabrication and Modeling
Abstract:
High mobility, electrolyte-gated FETs (EGFETs), based on precursor-derived oxide semiconductors, enable the possibility of achieving printed and low voltage (<2 V) operated circuits. These EGFETs can also be realized with displaced-gate geometries. However, the displaced-gate devices are typically slow due to high electrolyte resistance resulting from the large gate–channel distances. Here, we show that a thin insulating (composite solid polymer electrolyte) layer and a top-gate geometry can largely overcome this limitation, a comprehensive comparison between the displaced-gate and the top-gate devices has been provided. In order to facilitate circuit design, we have successfully developed accurate models to predict the behavior of these top-gate EGFETs. The importance of our modeling approach is further enhanced by the fact that appropriate predictive modeling strategies for printed circuits, especially for those that are based on oxide semiconductors, are largely missing. Unlike existing transistor models that do not cover all voltage regimes (below, near, and above threshold), we propose a new modeling methodology that matches very well with the measured data, is continuous and smooth over the entire voltage range, and can be easily incorporated into SPICE simulators.
Autors: Gabriel Cadilha Marques;Suresh Kumar Garlapati;Debaditya Chatterjee;Simone Dehm;Subho Dasgupta;Jasmin Aghassi;Mehdi B. Tahoori;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 279 - 285
Publisher: IEEE
 
» Electronic-Photonic Integrated Circuit for 3D Microimaging
Abstract:
An integrated electronic-photonic phase-locked loop (PLL) modulates the frequency of a tunable laser for use in frequency-modulated continuous-wave (FMCW) lidar 3D imaging. The proposed lidar can perform 180k range measurements per second. The rms depth precision is 8 at distances of ±5 cm from the range baseline. The range window is 1.4 m, with a precision of 4.2 mm at the edges of the window. Optical circuitry, including input light couplers, waveguides, and photodiodes, is realized on a 3 mm 3 mm silicon-photonic chip. The 0.18- CMOS ASIC of the same area comprises the front-end transimpedance amplifier, analog electro-optical PLL, and digital control circuitry consuming 1.7 mA from a 1.8 V supply and 14.1 mA from a 5-V supply. The latter includes 12.5-mA bias current for the distributed Bragg reflector section of the tunable laser. The two chips are integrated using through-silicon-vias implemented in the silicon-photonic chip.
Autors: Behnam Behroozpour;Phillip A. M. Sandborn;Niels Quack;Tae-Joon Seok;Yasuhiro Matsui;Ming C. Wu;Bernhard E. Boser;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jan 2017, volume: 52, issue:1, pages: 161 - 172
Publisher: IEEE
 
» Electrothermal Simulation-Based Comparison of 4H-SiC p-i-n, Schottky, and JBS Diodes Under High Current Density Pulsed Operation
Abstract:
Pulsed power applications are characterized by very high instantaneous power due to the high voltage and current involved. Power diodes used as a closing switch in pulsed power circuits must be able to withstand the high current operation well above the continuous device rating, for a transient duration. Due to the superior electrothermal properties of wide bandgap Silicon Carbide (SiC) material, it is feasible to develop high Blocking Voltage (BV) Schottky and Junction Barrier Schottky (JBS) diodes besides p-i-n rectifiers. In order to evaluate the device performance under high current density pulsed operation, 2-D models of SiC p-i-n, Schottky, and JBS diodes rated for 3.3-kV BV and 100 A/cm2 current density were developed using Silvaco ATLAS TCAD software. The diode structures were simulated electrothermally to study the device behavior and compare the performance under high current density pulsed operation. The power dissipation and the lattice temperature profile of the SiC diodes were analyzed to compare the magnitude of heat loss and formation of thermal hot spot in the diode structure to predict the suitability of the device for pulsed power applications.
Autors: Bejoy N. Pushpakaran;Stephen B. Bayne;Aderinto A. Ogunniyi;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 68 - 75
Publisher: IEEE
 
» Emerging Power Quality Problems and State-of-the-Art Solutions
Abstract:
The papers in this special section are devoted to the topic of solutions for power quality management. Although the power quality problems, such as, reactive and harmonic currents, distortion and fluctuations in the supply voltage, are not new to power system and power electronics researchers, the ever changing landscapes in the power generation and distribution systems have given rise to additional power quality challenges. The growing interest in the smart grid concepts, vehicle to grid operation, inverter based large scale photovoltaic (PV) and wind integration, distributed generators (DGs) as ancillary service provider, multilevel inverters for high power applications and so on is making the power quality aspects more prevalent.
Autors: Vinod Khadkikar;Dianguo Xu;Carlo Cecati;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 761 - 763
Publisher: IEEE
 
» Empirical Minimum Bayes Risk Prediction
Abstract:
When building vision systems that predict structured objects such as image segmentations or human poses, a crucial concern is performance under task-specific evaluation measures (e.g., Jaccard Index or Average Precision). An ongoing research challenge is to optimize predictions so as to maximize performance on such complex measures. In this work, we present a simple meta-algorithm that is surprisingly effective – Empirical Min Bayes Risk. EMBR takes as input a pre-trained model that would normally be the final product and learns three additional parameters so as to optimize performance on the complex instance-level high-order task-specific measure. We demonstrate EMBR in several domains, taking existing state-of-the-art algorithms and improving performance up to 8 percent, simply by learning three extra parameters. Our code is publicly available and the results presented in this paper can be replicated from our code-release.
Autors: Vittal Premachandran;Daniel Tarlow;Alan L. Yuille;Dhruv Batra;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2017, volume: 39, issue:1, pages: 75 - 86
Publisher: IEEE
 
» Employee of the month. Every month [Top Tech 2017]
Abstract:
Sami Haddadin once attached a knife to a robot manipulator and programmed it to impale his arm. No, it wasn’t a daredevil stunt. He was demonstrating how a new force-sensing control scheme he designed was able to detect the contact and instantly stop the robot, as it did.
Autors: Erico Guizzo;
Appeared in: IEEE Spectrum
Publication date: Jan 2017, volume: 54, issue:1, pages: 34 - 35
Publisher: IEEE
 
» EMYNOS: Next Generation Emergency Communication
Abstract:
Current emergency systems and 112 services are based on legacy telecommunication technologies, which cannot cope with IP-based services that European citizens use every day. Some of the related limitations are partial media support, the lack of integration of social media, and the use of an analog modem for providing eCall services with limited data amounts. As most operators have started migrating toward broadband IP-based infrastructures, current emergency systems also need to be upgraded and adapted in order to fulfill regulatory requirements in terms of next generation emergency services. This article presents the EMYNOS project, the goal of which is the design and implementation of a next generation platform capable of accommodating rich-media emergency calls that combine voice, text, and video, thus constituting a powerful tool for coordinating communication among citizens, call centers, and first responders. Additionally, issues such as call routing/redirection to the closest available call center, retrieval of caller location, support for people with disabilities, and integration of social media are detailed.
Autors: Evangelos K. Markakis;Asimakis Lykourgiotis;Ilias Politis;Anastasios Dagiuklas;Yacine Rebahi;Evangelos Pallis;
Appeared in: IEEE Communications Magazine
Publication date: Jan 2017, volume: 55, issue:1, pages: 139 - 145
Publisher: IEEE
 
» Enabling Communication Technologies for Smart Cities
Abstract:
Tremendous advancements in heterogeneous communication technologies have enabled smart cities objects to interact with each other while ensuring network connectivity. However, these communication technologies cannot provide flawless connectivity in smart cities due to the coexistence of thousands of devices, which brings about several problems. In this article, we discuss the enabling communication and networking technologies used in smart cities. The similarities and differences among different communication technologies based on the important parameters are also analyzed. Moreover, a taxonomy is devised by classifying the literature based on future and emerging technologies, modern communication technologies, IEEE wireless technology standards, objectives, network classes, and mode of operations. Furthermore, some reported case studies of different cities (Barcelona, Stratford, Singapore, and Porto) are also presented. Lastly, several research challenges, such as interference management, scalable wireless solutions, interoperability support among heterogeneous wireless networks, mobility management, and high energy consumption that remain to be addressed for enabling unimpaired connectivity in smart cities are discussed as future research directions.
Autors: Ibrar Yaqoob;Ibrahim Abaker Targio Hashem;Yasir Mehmood;Abdullah Gani;Salimah Mokhtar;Sghaier Guizani;
Appeared in: IEEE Communications Magazine
Publication date: Jan 2017, volume: 55, issue:1, pages: 112 - 120
Publisher: IEEE
 
» Enabling High-Level Synthesis Resource Sharing Design Space Exploration in FPGAs Through Automatic Internal Bitwidth Adjustments
Abstract:
High-level synthesis has some distinct advantages over traditional RT-level VLSI design. One key advantage is its ability to generate microarchitectures with unique area versus performance tradeoffs for the same behavioral description by setting different synthesis options. This is typically called design space exploration (DSE). One of the main ways to explore the design space for a particular behavioral description is by varying the amount of resource sharing allowed. For application-specified integrated circuits, increasing the amount of resource sharing normally leads to slower, but smaller designs, while decreasing the amount of resource sharing, leads to faster, but larger designs as the behavioral description can be further parallelized. In the field-programmable gate array (FPGA) case, this is normally not the case as sharing functional units (FUs) requires the insertion of multiplexers, which are very costly in terms of look up tables, while typical FUs, e.g., adders can very efficiently be mapped on the FPGAs’ resources and multipliers can be directly mapped to DSP macros. Hence, for the FPGA case, it traditionally does not make sense to explore the design space by varying the degree of resource sharing. This paper enables the DSE for FPGAs through resource sharing by fixing the bitwidth of selected internal variables and hence limiting the size of some FUs in the design. As it will be shown, the area savings from using smaller FUs, now outweighs the cost of the multiplexers and hence it is possible to achieve smaller microarchitectures. This comes at the expense of introducing potential overflow errors in the design. Experimental results show that our method enables the DSE of FPGAs using resource sharing and measures the error introduced for different types of input data distributions, showing that in some cases the error can be negligible, while in other cases it can be considerable.
Autors: Benjamin Carrion Schafer;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2017, volume: 36, issue:1, pages: 97 - 105
Publisher: IEEE
 
» Enabling IoT Ecosystems through Platform Interoperability
Abstract:
Today, the Internet of Things (IoT) comprises vertically oriented platforms for things. Developers who want to use them need to negotiate access individually and adapt to the platform-specific API and information models. Having to perform these actions for each platform often outweighs the possible gains from adapting applications to multiple platforms. This fragmentation of the IoT and the missing interoperability result in high entry barriers for developers and prevent the emergence of broadly accepted IoT ecosystems. The BIG IoT (Bridging the Interoperability Gap of the IoT) project aims to ignite an IoT ecosystem as part of the European Platforms Initiative. As part of the project, researchers have devised an IoT ecosystem architecture. It employs five interoperability patterns that enable cross-platform interoperability and can help establish successful IoT ecosystems.
Autors: Arne Bröring;Stefan Schmid;Corina-Kim Schindhelm;Abdelmajid Khelil;Sebastian Käbisch;Denis Kramer;Danh Le Phuoc;Jelena Mitic;Darko Anicic;Ernest Teniente;
Appeared in: IEEE Software
Publication date: Jan 2017, volume: 34, issue:1, pages: 54 - 61
Publisher: IEEE
 
» Enabling Low-Latency Applications in Fog-Radio Access Networks
Abstract:
The ultra low-latency operations of communications and computing enable many potential IoT applications, and thus have gained widespread attention recently. Existing mobile devices and telecommunication systems may not be able to provide the highly desired low-latency computing and communications services. To meet the needs of those applications, we introduce the Fog-Radio Access Network (F-RAN) architecture, which brings the efficient computing capability of the cloud to the edge of the network. By distributing computing-intensive tasks to multiple F-RAN nodes, F-RAN has the potential to meet the requirements of those ultra low-latency applications. In this article, we first introduce the F-RAN and its rationale in serving ultra low-latency applications. Then we discuss the need for a service framework for F-RAN to cope with the complex tradeoff among performance, computing cost, and communication cost. Finally, we illustrate the mobile AR service as an exemplary scenario to provide insights for the design of the framework. Examples and numerical results show that ultra low-latency services can be achieved by the F-RAN by properly handling the tradeoff.
Autors: Yuan-Yao Shih;Wei-Ho Chung;Ai-Chun Pang;Te-Chuan Chiu;Hung-Yu Wei;
Appeared in: IEEE Network
Publication date: Jan 2017, volume: 31, issue:1, pages: 52 - 58
Publisher: IEEE
 
» Enabling Mobile and Wireless Technologies for Smart Cities
Abstract:
Autors: Ejaz Ahmed;Muhammad Imran;Mohsen Guizani;Ammar Rayes;Jaime Lloret;Guangjie Han;Wael Guibene;
Appeared in: IEEE Communications Magazine
Publication date: Jan 2017, volume: 55, issue:1, pages: 74 - 75
Publisher: IEEE
 
» Enabling Parallel Simulation of Large-Scale HPC Network Systems
Abstract:
With the increasing complexity of today’s high-performance computing (HPC) architectures, simulation has become an indispensable tool for exploring the design space of HPC systems—in particular, networks. In order to make effective design decisions, simulations of these systems must possess the following properties: (1) have high accuracy and fidelity, (2) produce results in a timely manner, and (3) be able to analyze a broad range of network workloads. Most state-of-the-art HPC network simulation frameworks, however, are constrained in one or more of these areas. In this work, we present a simulation framework for modeling two important classes of networks used in today’s IBM and Cray supercomputers: torus and dragonfly networks. We use the Co-Design of Multi-layer Exascale Storage Architecture (CODES) simulation framework to simulate these network topologies at a flit-level detail using the Rensselaer Optimistic Simulation System (ROSS) for parallel discrete-event simulation. Our simulation framework meets all the requirements of a practical network simulation and can assist network designers in design space exploration. First, it uses validated and detailed flit-level network models to provide an accurate and high-fidelity network simulation. Second, instead of relying on serial time-stepped or traditional conservative discrete-event simulations that limit simulation scalability and efficiency, we use the optimistic event-scheduling capability of ROSS to achieve efficient and scalable HPC network simulations on today’s high-performance cluster systems. Third, our models give network designers a choice in simulating a broad range of network workloads, including HPC application workloads using detailed network traces, an ability that is rarely offered in parallel with high-fidelity network simulations.
Autors: Misbah Mubarak;Christopher D. Carothers;Robert B. Ross;Philip Carns;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 87 - 100
Publisher: IEEE
 
» Encoderless Identification of Two-Mass-Systems Utilizing an Extended Speed Adaptive Observer Structure
Abstract:
This paper describes a novel sensorless identification method for mechanical two-mass-systems and the influence of varying parameters and operation conditions on its performance. The identification procedure is carried out during the encoderless control of the drive system and based on the frequency response measurement of the mechanical setup. An extended speed adaptive observer structure serves as speed estimate for the calculation of the Bode diagram. The extension of the observer structure for speed estimation by a mechanical model allows a reliable identification of various two-inertia-systems within two identification steps. This paper gives an overview of the new identification procedure and the results of investigations toward its robustness and limitations. Varying speed and load conditions as well as different parameterizations of the signal processing method underline the applicability of the presented method.
Autors: Henning Zoubek;Mario Pacas;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 595 - 604
Publisher: IEEE
 
» EndoNet: A Deep Architecture for Recognition Tasks on Laparoscopic Videos
Abstract:
Surgical workflow recognition has numerous potential medical applications, such as the automatic indexing of surgical video databases and the optimization of real-time operating room scheduling, among others. As a result, surgical phase recognition has been studied in the context of several kinds of surgeries, such as cataract, neurological, and laparoscopic surgeries. In the literature, two types of features are typically used to perform this task: visual features and tool usage signals. However, the used visual features are mostly handcrafted. Furthermore, the tool usage signals are usually collected via a manual annotation process or by using additional equipment. In this paper, we propose a novel method for phase recognition that uses a convolutional neural network (CNN) to automatically learn features from cholecystectomy videos and that relies uniquely on visual information. In previous studies, it has been shown that the tool usage signals can provide valuable information in performing the phase recognition task. Thus, we present a novel CNN architecture, called EndoNet, that is designed to carry out the phase recognition and tool presence detection tasks in a multi-task manner. To the best of our knowledge, this is the first work proposing to use a CNN for multiple recognition tasks on laparoscopic videos. Experimental comparisons to other methods show that EndoNet yields state-of-the-art results for both tasks.
Autors: Andru P. Twinanda;Sherif Shehata;Didier Mutter;Jacques Marescaux;Michel de Mathelin;Nicolas Padoy;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 86 - 97
Publisher: IEEE
 
» Energy Aware Offloading for Competing Users on a Shared Communication Channel
Abstract:
This paper considers a set of mobile users that employ cloud-based computation offloading. In order to execute jobs in the cloud, the user uploads must occur over a base station channel that is shared by all of the uploading users. Since the job completion times are subject to hard deadline constraints, this restricts the feasible set of jobs that can be processed. The system is modelled as a competitive game in which each user is interested in minimizing its own energy consumption. The game is subject to the real-time constraints imposed by the job execution deadlines, user specific channel bit rates, and the competition over the shared communication channel. The paper shows that for a wide range of parameters, a game where each user independently sets its offloading decisions always has a pure Nash equilibrium, and a Gauss-Seidel-like method for determining this equilibrium is introduced. Results are presented that illustrate that the system always converges to a Nash equilibrium using the Gauss-Seidel method. Data is also presented that show the number of iterations required, and the quality of the solutions. We find that the solutions perform well compared to a lower bound on total energy performance.
Autors: Erfan Meskar;Terence D. Todd;Dongmei Zhao;George Karakostas;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 87 - 96
Publisher: IEEE
 
» Energy Detection Based Spectrum Sensing Over Two-Wave With Diffuse Power Fading Channels
Abstract:
One of the most important factors that affects the performance of energy detection (ED) is the fading channel between the wireless nodes. This paper investigates the performance of ED-based spectrum sensing, for cognitive radio (CR), over two-wave with diffuse power (TWDP) fading channels. The TWDP fading model characterizes a variety of fading channels, including well-known canonical fading distributions, such as Rayleigh and Rician, as well as worse-than-Rayleigh fading conditions modeled by the two-ray fading model. Novel analytic expressions for the average probability of detection over TWDP fading that account for single-user and cooperative spectrum sensing and square law selection diversity reception are derived. These expressions are used to analyze the behavior of ED-based spectrum sensing over moderate, severe, and extreme fading conditions and to investigate the use of cooperation and diversity as a means of mitigating the fading effects. The obtained results indicate that TWDP fading conditions can significantly degrade sensing performance; however, it is shown that detection performance can be improved when cooperation and diversity are employed. The presented outcomes enable identifying the limits of ED-based spectrum sensing and quantifying the tradeoffs between detection performance and energy efficiency for CR systems deployed within confined environments, such as in-vehicular wireless networks.
Autors: Eleftherios Chatziantoniou;Ben Allen;Vladan Velisavljevic;Petros Karadimas;Justin Coon;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 868 - 874
Publisher: IEEE
 
» Energy Efficiency Scaling Law of Massive MIMO Systems
Abstract:
Massive multi-input multi-output (MIMO) can support high spectral efficiency with simple linear transceivers, and is expected to provide high energy efficiency (EE). In this paper, we analyze the scaling laws of EE with respect to the number of antennas at each base station of downlink multi-cell massive MIMO systems under spatially correlated channel, where both transmit and circuit power consumptions, channel estimation errors, and pilot contamination (PC) are taken into account. We obtain the maximal EE for the systems with maximum-ratio transmission and zero-forcing beamforming for given numbers of antennas and users by optimizing the transmit power subject to the minimal data rate requirement and maximal transmit power constraint. The closed-form expressions of approximated EE-maximal transmit power and maximal EE, and their scaling laws with are derived. Our analysis shows that the maximal EE scales with in for the system without PC, and in for the system with PC. The EE-maximal transmit power scales up with in until reaching the maximal transmit power for the system without PC, and in for the system with PC. The analytical results are validated by simulations under a more realistic 3D channel model.
Autors: Wenjia Liu;Shengqian Han;Chenyang Yang;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 107 - 121
Publisher: IEEE
 
» Energy-Aware Cooperative Traffic Offloading via Device-to-Device Cooperations: An Analytical Approach
Abstract:
In this paper, we investigate the cooperative traffic offloading among mobiles devices (MDs) which are interested in receiving a common content from a cellular base station (BS). For offloading traffic, the BS first sends the content to some selected MDs which then broadcast the received data to the other MDs, such that each MD can receive the entire content simultaneously. Due to each MD's limited transmit-power and energy budget, the transmission rate of the content should be properly designed, since it strongly influences whether and how long each MD can perform relaying. Therefore, different from most existing MDs cooperative schemes, we focus on a novel joint optimization of the content transmission rate and each MD's relay-duration, with the objective of minimizing the system cost accounting for the energy consumption and the cellular-link usage. To tackle with the technical challenge due to the coupling effect between the content transmission rate and each MD's relay-duration, we exploit the decomposable property of the joint optimization problem, based on which we characterize different possible cases for achieving the optimal solution. We then derive the optimal solution for each case analytically, and further propose an efficient algorithm for finding the globally optimal solution of the original joint optimization problem. Numerical results are provided to validate the proposed algorithm (including its accuracy and computational efficiency) and demonstrate that the optimal MDs’ cooperative offloading can significantly reduce the system cost compared to some heuristic schemes. Several interesting insights about the cooperative offloading are also obtained.
Autors: Yuan Wu;Jiachao Chen;Li Ping Qian;Jianwei Huang;Xuemin Sherman Shen;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 97 - 114
Publisher: IEEE
 
» Energy-Aware Gateway Placement in Green Wireless Mesh Networks
Abstract:
In this letter, we address the following problem: given a mesh network deployment and gateways to be added, what is the optimal gateway placement with the constraint of energy-minimization for green wireless mesh networks. Unlike previous research, which focuses on throughput optimization, we contribute by developing a mixed-integer linear programming (MILP) formulation, which satisfies the given flow demands while minimizing the global energy consumption of the network. The proposed solution is NP-hard; therefore, we also propose a heuristic-based greedy algorithm to efficiently solve large instances of this problem. To capture interference in the mesh network, we use the physical-interference model but employ a greedy algorithm to reduce the computation time for finding maximal independent sets. We implement both the MILP formulation and the greedy solution along with three other contemporary solutions in the area. Numerical results show that the proposed exact scheme provides the optimal result, while the greedy solution provides a solution within 5% of the optimal solution with just 1% computation time for green wireless mesh networks.
Autors: Usman Ashraf;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 156 - 159
Publisher: IEEE
 
» Energy-Aware Wireless Relay Selection in Load-Coupled OFDMA Cellular Networks
Abstract:
We investigate transmission energy minimization via optimizing wireless relay selection in orthogonal-frequency-division multiple access networks. We take into account the impact of the load of cells on transmission energy. We prove the -hardness of the energy-aware wireless relay selection problem. To tackle computational complexity, a partial optimality condition is derived for providing insights in respect of designing an effective and efficient algorithm. Numerical results show the resulting algorithm achieves high energy performance.
Autors: Lei You;Di Yuan;Nikolaos Pappas;Peter Värbrand;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 144 - 147
Publisher: IEEE
 
» Energy-Efficient Autonomous Solar Water-Pumping System for Permanent-Magnet Synchronous Motors
Abstract:
This paper presents a novel stand-alone solar-powered water-pumping system, especially suited for usage in rural or remote areas. The system is primarily designed to reduce both cost and complexity, while simultaneously guaranteeing optimal utilization of the photovoltaic generator. The use of standard hardware and control architectures ensures ease of installation, service, and maintenance. The proposed solution consists of a water pump driven by a permanent-magnet synchronous motor, controlled by a conventional field oriented control scheme. The photovoltaic array is directly connected to the dc bus of the inverter, with no intermediate power conversion stages. A perturbation based extremum-seeking controller adjusts the motor speed reference to attain the maximum power point operation of the photovoltaic array. Both simulations and experimental results on a full-scale prototype support the effectiveness of the proposed system.
Autors: Riccardo Antonello;Matteo Carraro;Alessandro Costabeber;Fabio Tinazzi;Mauro Zigliotto;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 43 - 51
Publisher: IEEE
 
» Energy-Efficient Bandwidth Aggregation for Delay-Constrained Video Over Heterogeneous Wireless Networks
Abstract:
The spectrum limitation of single wireless networks prompts the bandwidth aggregation of heterogeneous access medium (e.g., LTE and Wi-Fi) to support high-quality real-time video services. Energy consumption of mobile devices is of vital significance to provide user-satisfied multimedia streaming applications. However, it is challenging to develop an energy-efficient bandwidth aggregation scheme with regard to the stringent delay and quality constraints imposed by wireless video transmission. To address the critical problem, this paper presents an Energy-quaLity aware Bandwidth Aggregation (ELBA) scheme. First, we develop an analytical framework to model the delay-constrained energy-quality tradeoff for multipath video transmission over heterogeneous wireless networks. Second, we propose a bandwidth aggregation framework that integrates energy-minimized rate adaptation, delay-constrained unequal protection, and quality-aware packet distribution. The proposed ELBA scheme is able to effectively leverage the wireless channel diversity and video frame priority for enabling energy-minimized quality-guaranteed streaming to multihomed devices within imposed deadline. We conduct the performance evaluation through both experiments over real wireless networks and extensive emulations in Exata platform. Experimental results demonstrate the performance advantages of ELBA over existing bandwidth aggregation schemes in energy conservation, video quality, and end-to-end delay.
Autors: Jiyan Wu;Bo Cheng;Ming Wang;Junliang Chen;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2017, volume: 35, issue:1, pages: 30 - 49
Publisher: IEEE
 
» Energy-Efficient Cooperation in Cognitive Wireless Powered Networks
Abstract:
In this letter, we consider a cooperative sharing model for cognitive wireless powered communication networks (CWPCNs), which leverages the notion of cooperation between primary and secondary systems in cognitive radio networks to accomplish primary transmission early and vacate opportunity for secondary transmission. With the proposed spectrum sharing model, we investigate the optimal design for such a cooperative CWPCN with both amplify-and-forward (AF) and decode-and-forward (DF) protocols to maximize its uplink energy efficiency. The energy efficiency optimization problem is decomposed into two subproblems for uplink scheduling and cooperative power control. We also propose a suboptimal solution to tackle the unavailable information on channel condition between the primary transmitter and secondary users. The numerical results show that the DF protocol outperforms the AF protocol in general and the suboptimal solution is slightly outperformed by the optimal one.
Autors: Sixing Yin;Zhaowei Qu;Zhi Wang;Lihua Li;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 128 - 131
Publisher: IEEE
 
» Energy-Efficient Nonvolatile Reconfigurable Logic Using Spin Hall Effect-Based Lookup Tables
Abstract:
In this paper, we leverage magnetic tunnel junction (MTJ) devices to design an energy-efficient nonvolatile lookup table (LUT), which utilizes a spin Hall effect (SHE) assisted switching approach for MTJ storage cells. SHE–MTJ characteristics are modeled in Verilog-A based on precise physical equations. Functionality of the proposed SHE–MTJ-based LUT is validated using SPICE simulation. Our proposed SHE—MTJ-based LUT (SHE–LUT) is compared with the most energy-efficient MTJ-based LUT circuits. The obtained results show more than 6%, 37%, and 67% improvement over three previous MTJ-based designs in term of read energy consumption. Moreover, the reconfiguration delay and energy of the proposed design is compared with that of the MTJ-based LUTs which utilize the spin transfer torque (STT) switching approach for reconfiguration. The results exhibit that SHE–LUT can operate at 78% higher clock frequency while achieving at least 21% improvement in terms of reconfiguration energy consumption. The operation-specific clocking mechanisms for managing the SHE–LUT operations are introduced along with detailed analyses concerning tradeoffs. Results are extended to design a 6-input fracturable LUT using SHE–MTJs.
Autors: Ramtin Zand;Arman Roohi;Deliang Fan;Ronald F. DeMara;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 32 - 43
Publisher: IEEE
 
» Energy-Efficient Relay Selection of Cooperative HARQ Based on the Number of Transmissions Over Rayleigh Fading Channels
Abstract:
Cooperative hybrid automatic retransmission request (C-HARQ) is a simple and effective method for wireless communication. Since its performance largely depends on the selection of a relevant relay, the design of an appropriate relay selection scheme is very important. Although various works have been performed on this topic, most of them did not take into account both the “not memoryless” and multiple retransmission characteristics of C-HARQ, resulting in the loss of achievable performance. In this paper, we propose a novel cooperative relay selection scheme in a distributed manner called transmission number relaying (TNR) to simultaneously reduce the outage probability and increase the energy efficiency by utilizing the features of C-HARQ. The TNR scheme determines a single relay based on the estimated number of transmissions, which is calculated from the channel condition. Using these numbers instead of just the channel condition improves the outage probability and reduces the total consumed energy. The exact probability of the number of transmissions at each relay and the outage probability are analyzed, and the numerical results show that the proposed scheme significantly improves the outage probability and reduces the total consumed energy. In addition, when the number of available relays is small, the proposed scheme achieves high energy efficiency.
Autors: Jinhwan Kim;Kyungmin Kim;Jaiyong Lee;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 610 - 621
Publisher: IEEE
 
» Energy-Efficient Sparse Beamforming for Multiuser MIMO Systems With Nonideal Power Amplifiers
Abstract:
In this paper, we consider energy-efficiency (EE) optimization problems with nonideal power amplifier (PA) models, per-antenna power constraints, and minimal spectral efficiency (SE) requirements in block-diagonalization-based multiuser multiple-input–multiple-output (MU-MIMO) systems. In the problem formulation, a joint optimization of the transmit covariance and the active transmit antenna set at the base station is considered. In general, the problem is a mixed-integer fractional programming problem, and it is difficult to solve it globally optimally. By reformulating the original problem as a sparse beamforming design problem and using a successive convex approximation method, we propose an iterative algorithm to solve it locally. In each iteration step, a concave fractional programming is solved, and the solution can be expressed in closed form with the help of the Lagrange dual method. Simulation results are used to verify the performance of our proposed algorithms. We also study the EE–SE tradeoff for the considered system. In fact, the relationship between EE and SE under an ideal PA model is not accurate for realistic systems. We characterize the EE–SE tradeoff under nonideal PA models by solving the EE maximization problems under different SE values. In this way, we can also shed light on the design of the system parameters to optimize the EE–SE curve. We find that with nonideal PA considered, the SE corresponding to the optimal EE will increase, compared with the ideal case. If we design the system parameters according to the optimal SE under an ideal PA model to maximize the EE, both the EE and the SE of the realistic system will decrease. We also find that when the proposed antenna selection algorithm is applied, the achieve region of the EE and the SE is expanded, particularly when the SE is low. In other words, the EE–SE win–win region is- enlarged, and the EE–SE tradeoff is improved.
Autors: Yitian Dong;Yi Huang;Ling Qiu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 134 - 145
Publisher: IEEE
 
» Energy-Efficient Time Synchronization Based on Asynchronous Source Clock Frequency Recovery and Reverse Two-Way Message Exchanges in Wireless Sensor Networks
Abstract:
We consider energy-efficient time synchronization in a wireless sensor network where a head node is equipped with a powerful processor and supplied power from outlet, and sensor nodes are limited in processing and battery-powered. It is this asymmetry that our study focuses on; unlike most existing schemes to save the power of all network nodes, we concentrate on battery-powered sensor nodes in minimizing energy consumption for time synchronization. We present a time synchronization scheme based on asynchronous source clock frequency recovery and reverse two-way message exchanges combined with measurement data report messages, where we minimize the number of message transmissions from sensor nodes while achieving sub-microsecond time synchronization accuracy through propagation delay compensation. We carry out the performance analysis of the estimation of both measurement time and clock frequency with lower bounds for the latter. Simulation results verify that the proposed scheme outperforms the schemes based on conventional two-way message exchanges with and without clock frequency recovery in terms of the accuracy of measurement time estimation and the number of message transmissions and receptions at sensor nodes as an indirect measure of energy efficiency.
Autors: Kyeong Soo Kim;Sanghyuk Lee;Eng Gee Lim;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 347 - 359
Publisher: IEEE
 
» Energy-Harvesting-Aided Spectrum Sensing and Data Transmission in Heterogeneous Cognitive Radio Sensor Network
Abstract:
The incorporation of cognitive radio (CR) and energy harvesting (EH) capabilities in wireless sensor networks enables spectrum and energy-efficient heterogeneous CR sensor networks (HCRSNs). The new networking paradigm of HCRSNs consists of EH-enabled spectrum sensors and battery-powered data sensors. Spectrum sensors can cooperatively scan the licensed spectrum for available channels, whereas data sensors monitor an area of interest and transmit sensed data to the sink over those channels. In this paper, we propose a resource-allocation solution for the HCRSN to achieve the sustainability of spectrum sensors and conserve the energy of data sensors. The proposed solution is achieved by two algorithms that operate in tandem: a spectrum sensor scheduling (SSS) algorithm and a data sensor resource allocation (DSRA) algorithm. The SSS algorithm allocates channels to spectrum sensors such that the average detected available time for the channels is maximized, while the EH dynamics are considered and primary user (PU) transmissions are protected. The DSRA algorithm allocates the transmission time, power, and channels such that the energy consumption of the data sensors is minimized. Extensive simulation results demonstrate that the energy consumption of the data sensors can be significantly reduced, while maintaining the sustainability of the spectrum sensors.
Autors: Deyu Zhang;Zhigang Chen;Ju Ren;Ning Zhang;Mohamad Khattar Awad;Haibo Zhou;Xuemin Sherman Shen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 831 - 843
Publisher: IEEE
 
» ENFIRE: A Spatio-Temporal Fine-Grained Reconfigurable Hardware
Abstract:
Field programmable gate arrays (FPGAs) are well-established as fine-grained reconfigurable computing platforms. However, FPGAs demonstrate poor scalability in advanced technology nodes due to the large negative impact of the elaborate programmable interconnects (PIs). The need for such vast PIs arises from two key factors: 1) fine-grained bit-level data manipulation in the configurable logic blocks and 2) the purely spatial computing model followed in the FPGAs. In this paper, we propose ENFIRE, a novel memory-based spatio-temporal framework designed to provide the flexibility of reconfigurable bit-level information processing while improving scalability and energy efficiency. Dense 2-D memory arrays serve as the main computing elements storing not only the data to be processed but also the functional behavior of the application mapped into lookup tables. Computing elements are spatially distributed, communicating as needed over a hierarchical bus interconnect, while the functions are evaluated temporally inside each computing element. A custom software framework facilitates application mapping to the framework. By leveraging both spatial and temporal computing, ENFIRE significantly reduces the interconnect overhead when compared with FPGA. Simulation results show an improvement of in energy, in energy efficiency, in leakage, and in unified energy efficiency, a metric that considers energy and area together, compared with comparable FPGA implementations.
Autors: Wenchao Qian;Christopher Babecki;Robert Karam;Somnath Paul;Swarup Bhunia;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 177 - 188
Publisher: IEEE
 
» Engineering, Human, and Legal Challenges of Navigation Systems for Personal Mobility
Abstract:
Walking is now promoted as an alternative transport mode to polluting cars and as a successful means to improve health and longevity. Intelligent transport systems navigation services are now directly targeting travelers due to smartphones and their embedded sensors. However, after a decade of research, no universal personal navigation system has been successfully introduced and adopted to improve personal mobility. An analysis of the underlying reasons is conducted, looking at the engineering, human, ethical, and legal challenges. First, contrary to adopting classical mechanization equations linked to solid state physics, location technologies must address complex personal dynamics using connected objects. Second, human factors are often not sufficiently considered while designing new technologies. The needs and abilities of travelers are not systematically addressed from a user-centered perspective. Finally, people want to benefit from location-based services without sharing personal location data to uncontrolled third bodies. Europe is a pioneer in the protection of individuals from personal identification through data processing since location data has been recognized as personal data, but the challenges to enforce the regulation are numerous. The recommendation of “privacy by design and default” is an interesting key to conceive the universal personal navigation solution. Alternative solutions are highlighted, but they definitively require a more interdisciplinary conception.
Autors: Valérie Renaudin;Aurélie Dommes;Michèle Guilbot;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2017, volume: 18, issue:1, pages: 177 - 191
Publisher: IEEE
 
» Engineers with disabilities: inveterate problem solvers [Resources_Careers]
Abstract:
After graduating, mechanical engineer Kurt Driscoll endured more than 100 interviews over 10 months before he was finally hired. A quadriplegic, he encountered some who told him that he couldn’t do the job, while others simply claimed to be “going in a different direction.”
Autors: Theresa Sullivan Barger;
Appeared in: IEEE Spectrum
Publication date: Jan 2017, volume: 54, issue:1, pages: 19 - 19
Publisher: IEEE
 
» Enhanced Frequency Response Strategy for a PMSG-Based Wind Energy Conversion System Using Ultracapacitor in Remote Area Power Supply Systems
Abstract:
Conventional generators in wind–diesel hybrid remote-area power supply (RAPS) systems are likely to be heavily stressed during frequency disturbances due to poor frequency response of power electronic interfaced wind energy conversion systems (WECSs). Hence, it is imperative for the WECS to provide frequency support during frequency excursions. However, existing frequency control strategies are slow and will also impose severe mechanical/electromagnetic stress on WECSs. In this paper, frequency response strategies for the PMSG-based WECS are explored, and an enhanced frequency response strategy is investigated to regulate the RAPS system frequency jointly with the integrated ultracapacitors. The proposed short-term frequency response strategy utilizes a virtual inertial technique along with the supplementary droop control. Suboptimal power-point-tracking is also implemented at the PMSG to improve the active power reserve. The enhanced frequency response strategy can regulate the RAPS system frequency while alleviating high rate-of-change-of-power, and thus stresses on both the conventional generator and PMSG under frequency disturbances. Proposed control strategies are validated by both simulations and experiments.
Autors: Yingjie Tan;Kashem M. Muttaqi;Phil Ciufo;Lasantha Meegahapola;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 549 - 558
Publisher: IEEE
 
» Enhancement of $f_{mathrm {max}}$ to 910 GHz by Adopting Asymmetric Gate Recess and Double-Side-Doped Structure in 75-nm-Gate InAlAs/InGaAs HEMTs
Abstract:
A high maximum frequency of oscillation () of 910 GHz was achieved at InAlAs/InGaAs high-electron mobility transistors (HEMTs) with a relatively long gate length () of 75 nm by adopting an asymmetric gate recess and a double-side-doped structure. The improved significantly by extending the drain-side gate recess length () to 250 nm; meanwhile, the source-side gate-recess length () was kept to 70 nm. The improvement in was due to a decrease in the drain output conductance () and drain-to-gate capacitance () after the extension of . was further suppressed by applying a double-side-doped structure to the InP-based HEMTs. A reduction in resulted in a drastic improvement in even though was a longer value.
Autors: Tsuyoshi Takahashi;Yoichi Kawano;Kozo Makiyama;Shoichi Shiba;Masaru Sato;Yasuhiro Nakasha;Naoki Hara;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 89 - 95
Publisher: IEEE
 
» Ensuring Profitability of Energy Storage
Abstract:
Energy storage (ES) is a pivotal technology for dealing with the challenges caused by the integration of renewable energy sources. It is expected that a decrease in the capital cost of storage will eventually spur the deployment of large amounts of ES. These devices will provide transmission services, such as spatiotemporal energy arbitrage, i.e., storing surplus energy from intermittent renewable sources for later use by loads while reducing the congestion in the transmission network. This paper proposes a bilevel program that determines the optimal location and size of storage devices to perform this spatiotemporal energy arbitrage. This method aims to simultaneously reduce the system-wide operating cost and the cost of investments in ES while ensuring that merchant storage devices collect sufficient profits to fully recover their investment cost. The usefulness of the proposed method is illustrated using a representative case study of the ISO New England system with a prospective wind generation portfolio.
Autors: Yury Dvorkin;Ricardo Fernández-Blanco;Daniel S. Kirschen;Hrvoje Pandžić;Jean-Paul Watson;Cesar A. Silva-Monroy;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 611 - 623
Publisher: IEEE
 
» Entrainment Control of Phase Dynamics
Abstract:
First order phase reduced model is a good approximation of the dynamics of forced nonlinear oscillators near its limit cycle. The phase evolution is determined by the unforced frequency, the forcing term, and the phase response curve (PRC). Such models arise in biological oscillations such as in circadian rhythm, neural signaling, heart beat, etc. This technical note focuses on the phase regulation of the circadian rhythm using light intensity as the input. Though the model is simple, the circle topology of the state space needs to be carefully addressed. The most common entrainment method is to use a periodic input, such as in our daily light-dark cycle. We obtain the complete stable entrainment condition based on the entraiment input and the PRC. Motivated by the jet-lag problem, we also consider the minimum time entrainment control to achieve a specified phase shift. Application of the Pontryagin Minimum Principle leads to an efficient solution strategy for the optimal control, without solving the two-point boundary value problem. The optimal control may be further represented as a feedback control law based on the current and desired phases. Our analysis allows the answer to questions such as: When traveling from New York to Paris, is it faster to use light to shift the phase forward by 6 hours or delay the phase by 18 hours? The answer is somewhat counter-intuitive—delaying by 18 hours requires less time. The general answer depends on the light intensity level and the shape of the PRC. PRCs for human and Drosophila from the literature are used to illustrate the results.
Autors: Wei Qiao;John T. Wen;Agung Julius;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 445 - 450
Publisher: IEEE
 
» Environment Exploration in Sensing Automation for Habitat Monitoring
Abstract:
We present algorithms for environment exploration in the context of a habitat monitoring task, where the goal is to track radio-tagged invasive fish with autonomous surface or ground robots. The first task is navigation around an unknown obstacle using an input from a front-facing sonar. This capability is important for navigation on inland lakes, because plants and shallow shorelines are hard to map in advance. The second task involves energy harvesting for long-term operation. We address the problem of exploring the solar map of the environment which is used for energy-efficient navigation. For both problems, we present online algorithms and examine their performance using competitive analysis. In competitive analysis, the performance of an online algorithm is compared against the optimal offline algorithm. For obstacle avoidance, the offline algorithm knows the shape of the obstacle. For solar exploration, the offline algorithm knows the geometry of the shadow-casting objects. We obtain an competitive ratio for obstacle avoidance and an competitive ratio for solar exploration, where is the number of critical points to observe. The strategies for obstacle avoidance are validated through extensive field experiments, and the strategies for exploration are validated with simulations.
Autors: Patrick A. Plonski;Joshua Vander Hook;Cheng Peng;Narges Noori;Volkan Isler;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 25 - 38
Publisher: IEEE
 

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