#### Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 17

» Temperature-Compensated $\beta$ -Multiplier Current Reference Circuit
 Abstract:This brief presents the new simple schematic for the temperature stable current references based on the well-known -multiplier circuit. The proposed reference utilizes only four MOS transistors and two lateral PNP transistors, which are usually available in standard CMOS technologies along with one well resistor. The temperature-compensation technique has a low process dependence and needs no trimming. However, resistor trimming can be used to precisely set the output current value. The circuit implementation of the proposed technique was fabricated in a standard 0.35- CMOS process to source a 16- current. The digital calibration circuit allows setting of the output current in 32 100 nA-steps. The proposed current reference achieves the supply sensitivity of several %/V without the use of the external bandgap voltage reference for the supply regulation. The measured temperature coefficient is 105 ppm/°C over the temperature range from 0 to 110 °C. Autors: Dmitry Osipov;Steffen Paul; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Oct 2017, volume: 64, issue:10, pages: 1162 - 1166 Publisher: IEEE
» Temporal Interaction and Causal Influence in Community-Based Question Answering
» Test of Device Based on Disk Magnetocumulative Generator DMCG480 With Explosive Current Opening Switch
 Abstract:One of the perspective directions in high-energy-density physics is the creation of powerful electro physical facilities capable to form megampere current pulses with short front. This paper presents test results of the device based on five-element disk magnetocumulative generator DMCG480 and an explosive current opening switch. The current pulse of 15 MA with characteristic rise time of was obtained in the equivalent multiwire array load of 17 nH at circuit breaking with the current of 32 MA. Autors: Vasily A. Demidov;Sergey N. Golosov;Alexander S. Boriskin;Sergey A. Kazakov;Olga M. Tatsenko;Yuri V. Vlasov;Alexander P. Romanov;Alexey V. Filippov;Ekaterina A. Bychkova;Alexander N. Moiseenko;Eugeny I. Schetnikov;Sergey V. Kutumov;Natalya R. Kazakov Appeared in: IEEE Transactions on Plasma Science Publication date: Oct 2017, volume: 45, issue:10, pages: 2674 - 2677 Publisher: IEEE
» The Background Noise Environment During the 2013 Target and REverberation eXperiment
 Abstract:This paper presents an analysis of the time- and frequency-domain properties of a multiday series of background noise during the Target and REverberation eXperiment (TREX13) that took place off the coast of Panama City, FL, USA. Background noise was measured at two locations approximately 5 and 6 km south-east of the location of the R/V Sharp where monostatic reverberation was measured. The median spectral density level estimated for a frequency band centered at 2.7 kHz with a bandwidth of 1800 Hz was comparable to the median level at 3.5 kHz averaged over a bandwidth of 100 Hz; both were estimated to be 60 dB re 1 Pa/Hz when averaged during the day or night. In contrast, the level at 4.5 kHz, estimated by averaging over a bandwidth of 100 Hz, increased by 14 dB at night. While the data suggest a degree of consistency in the background environment for the purposes of modeling, when assessing levels in the 80–8000 Hz frequency band, time of day was found to be influential. The median spectral levels presented may be used to assess the influence of background noise at a given time of day. Biological noise likely from fish was revealed to be a significant contributor to background noise at night, and daytime background noise levels were primarily influenced by wind. Autors: Dara M. Farrell;David R. Dall’Osto;Peter H. Dahl; Appeared in: IEEE Journal of Oceanic Engineering Publication date: Oct 2017, volume: 42, issue:4, pages: 1088 - 1093 Publisher: IEEE
» The Barrier-Breach Problem of Barrier Coverage in Wireless Sensor Networks
 Abstract:When there are multiple barriers in a wireless sensor network (WSN), the sleep–wakeup schedule can be used to alternate working barriers to extend the overall network lifetime. However, when one working barrier is being replaced by another, if any intruder comes into the potential-breach-point between these two barriers, the barrier-breach problem may occur. In this letter, the proposed algorithm uses mobile elements to check presence of intruders at potential-breach-points. Compared with the extant algorithms, the proposed algorithm has two major advantages. First, it does not remove crossing barriers, so the overall network lifetime of barrier coverage can be extended. Second, it does not alternate working barriers always based on the order of barrier’s distance to the front side, from near to far, so the sleep–wakeup schedule can be flexibly arranged. Autors: Chien-Fu Cheng;Chen-Wei Wang; Appeared in: IEEE Communications Letters Publication date: Oct 2017, volume: 21, issue:10, pages: 2262 - 2265 Publisher: IEEE
» The Big Picture of the IEEE [The Way Ahead]
 Abstract:Discusses the benefits of becoming a student member of the IEEE. Autors: J. Patrick Donohoe; Appeared in: IEEE Potentials Publication date: Oct 2017, volume: 36, issue:5, pages: 4 - 4 Publisher: IEEE
» The bitcoin mines of China
 Abstract:In the dusty, sunbaked land surrounding Ordos, a city in China's Inner Mongolia, sits one of the world's largest bitcoin mines. Encircled by coal-fired power plants, rare earth mineral extraction sites, and the skeletal remains of abandoned, half-constructed housing complexes, the Bitmain Technologies bitcoin mine is evidence of a new economic boom in the area. Every 10 minutes, a new block of data is added to the Bitcoin blockchain, the accounting ledger that records every transaction made with the currency. And every 10 minutes, a shiny new cache of bitcoins is deposited into the digital pocket of the person whose computer added the most recent block. Miners compete for the right to add new blocks by running a single calculation, the SHA-256 hash function, over and over as fast as they can. This essentially enters them into a lottery with all other miners on the network. The rewards of this lottery now amount to over US $8 million worth of bitcoins every day. Half of this goes to miners in China, who own a majority of the hashing power on the Bitcoin network, according to a new study by University of Cambridge researchers. Their proximity to manufacturers of specialized hardware and their access to cheap land and cheap electricity make Chinese miners the natural beneficiaries of the Bitcoin system, which rewards efficiency and hustle above all else. Autors: Stefen Chow;Morgen E. Peck; Appeared in: IEEE Spectrum Publication date: Oct 2017, volume: 54, issue:10, pages: 46 - 53 Publisher: IEEE » The blossoming of the blockchain  Abstract:WHEN BITCOIN WAS unleashed on the world eight years ago, it filled a specific need, for a digital currency that wasn't under anybody's control. But it wasn't long before people realized the technology behind Bitcoin-the blockchain-could do much more than record monetary transactions. . That realization has lately blossomed into a dazzling and often bewildering array of startup companies, initiatives, corporate alliances, and research projects. Collectively, they're facing a question that will have an enormous impact: What can the blockchain do better than conventional databases? Billions of dollars will hinge on the answer in the next several years. . Can the technology link neighborhood buyers and sellers of rooftop-generated solar electricity? Can it keep track of property titles, academic transcripts, energy market credits, and state licenses for health care providers? Can it check the status of airline flights-and make reparations to weary travelers if their flights are delayed? We'll soon see: All of those proposals have been embodied in blockchain-based agreements called smart contracts, which are being tested right now. Autors: Morgen E. Peck;Samuel K. Moore; Appeared in: IEEE Spectrum Publication date: Oct 2017, volume: 54, issue:10, pages: 24 - 25 Publisher: IEEE » The Coordinated Development Path of Renewable Energy and National Economy in China Considering Risks of Electricity Market and Energy Policy  Abstract:The long-standing over-reliance on fossil fuels brings urgent environmental issues. To reduce emissions and maintain a sustained economic growth, many countries seek for energy revolution. With the help of smart grid technology, renewable energy eventually plays an indispensable role in energy production and consumption. Electricity market mechanisms and energy policies are thus developed rapidly and can pose more risks to national economy. This paper proposes a modified computable general equilibrium (CGE) model for China to evaluate these risks. Based on several economic evaluation indices, the coordinated development path of renewable energy and national economy is put forward. Industrial restructuring is considered in the modified CGE model since it is one of the key economic policies in today's China. Numerical studies are conducted based on real-world data, and sensitivity analysis further illustrates how different factors affect the results. Autors: Yunpeng Xiao;Xifan Wang;Xiuli Wang;Zechen Wu;Wei Liu; Appeared in: IEEE Transactions on Industrial Informatics Publication date: Oct 2017, volume: 13, issue:5, pages: 2566 - 2575 Publisher: IEEE » The dark dialect [Technically Speaking]  Abstract:PART OF THE MYTHOLOGY OF THE EARLY INTERNET was that it was going to make the world a better place by giving voice to the masses and leveling playing fields. Light was the metaphor of choice. For example, Apple cofounder Steve Wozniak once said that "when the Internet ﬁrst came, I thought it was just the beacon of freedom." . You can easily make a case for how much "brighter" the world is now, thanks to ubiquitous connectivity shining a light on misbehavior and malfeasance, but the Internet has a dark side as well. . For example, when you enter a search term into Google and it spits out the results, you might think that the search engine spent those few milliseconds querying the entire Web. Nope, not even close. What Google indexes is a fraction of all the available Web, perhaps just 4 percent of the total, by some estimates. That indexed soupcon is called the surface Web, or sometimes the visible Web. What about the other 96 percent? That nonsearchable content is called the deep Web, dark Web, or sometimes the invisible Web. A related idea is dark social, those online social interactions that are not public and cannot be directly tracked or traced (such as text messages and emails). Autors: Paul Mcfedries;Margaret Atwood; Appeared in: IEEE Spectrum Publication date: Oct 2017, volume: 54, issue:10, pages: 22 - 22 Publisher: IEEE » The Delta-Connected Cascaded H-Bridge Converter Application in Distributed Energy Resources and Fault Ride Through Capability Analysis  Abstract:This paper presents a flexible dc voltage balancing control technique of the modular multilevel cascaded converter with single-delta bridge-cells (MMCC-SDBC) in the distributed energy resources (DERs) system for maintaining the stable operation under different unbalanced conditions. The unbalanced conditions, for example, the different output powers of the DERs in bridge cells, and the unbalanced grid faults are considered in the proposed method. In addition, the comparison of the fault ride through capability between MMCC with single-star bridge-cells and MMCC-SDBC is addressed. The laboratory test results are given to verify the proposed method and the analysis. Autors: Ping-Heng Wu;Yuh-Tyng Chen;Po-Tai Cheng; Appeared in: IEEE Transactions on Industry Applications Publication date: Oct 2017, volume: 53, issue:5, pages: 4665 - 4672 Publisher: IEEE » The Design of Clocked-Comparator-Based Time-Interval Measurement Circuit for Pulse ToF Measurement  Abstract:A clocked-comparator-based time-interval measurement approach is proposed for the measurement of the time-of-flight (ToF) of wave pulses in a threshold-crossing-detection-based pulse ToF range-finding application. As compared to the conventional TDC-based pulse ToF measurement approach, the proposed approach does not require the use of extra channels in the case where multiple echoes can be expected for every wave pulse launched. As compared to the conventional (flash) analog-to-digital converter-based pulse ToF measurement approach, the proposed approach allows for a simpler backend digital processing and does not require the comparators used in the measurement to be skew-less. Meanwhile, the approach leverages on the strength of a clocked comparator circuit, which can be designed with a very wide sampling bandwidth. A clocked-comparator-based time-interval measurement circuit with a ~7-GHz bandwidth was assembled using low cost commercial-of-the-shelf components. The measurements done using the measurement circuit agree to within 10 ps with the same measurements done using a 13-GHz, 40-GSa/s oscilloscope and are precise to within ±15 ps in terms of their range. Autors: Gibran Limi Jaya;Shoushun Chen;Liter Siek; Appeared in: IEEE Sensors Journal Publication date: Oct 2017, volume: 17, issue:20, pages: 6699 - 6706 Publisher: IEEE » The DoF of Two-Way Butterfly Networks  Abstract:This letter studies the two-way butterfly network, a class of two-way four-unicast networks. We first show that bidirectional links do not increase the degrees of freedom for this network, thus giving the first example of a network to the best of our knowledge, where bidirectional links do not increase the degrees of freedom. Furthermore, we show that sufficient caching at the relays or increasing the number of antennas at the relays can double the degrees of freedom for the two-way butterfly network. Autors: Mehdi Ashraphijuo;Vaneet Aggarwal;Xiaodong Wang; Appeared in: IEEE Communications Letters Publication date: Oct 2017, volume: 21, issue:10, pages: 2254 - 2257 Publisher: IEEE » The Effects of Taper-Angle on the Electrical Characteristics of Vertical NAND Flash Memories  Abstract:The effects of taper angle of the string and the number of layers on the electrical characteristics of vertical NAND flash memories are investigated. Simulation results show that the transconductance and the threshold voltage distribution over the position of the cell along the string depend on taper angle and the number of layers. There is a taper angle that minimizes the spread of threshold voltage, and hence, the impact of the random telegraph noise and this angle depends on the number of layers. These results will be helpful in designing the vertical NAND flash memories. Autors: Kee Tae Kim;Sung Woo An;Hyun Soo Jung;Keon-Ho Yoo;Tae Whan Kim; Appeared in: IEEE Electron Device Letters Publication date: Oct 2017, volume: 38, issue:10, pages: 1375 - 1378 Publisher: IEEE » The Entropy Value for ECG of the Sport Horses  Abstract:In this study, we compared the amplitude and the duration of and waves of sport horses before a training program with after a training program. Waves are transformed to the entropies by the same methods of Şengönül et al., “The entropy of the waves and in electrocardiogram and some comments,” Int. J. Math. Model. Comput., vol. 6, pp. 159–173, 2016. We have benefitted from the definition of fuzzy sets and have assigned an entropy for each and waves of sport horses. Then, we have calculated Cesàro entropies for each wave in a particular segment for ten beats. In addition, the graphical representations are obtained for healthy and diseased horses by formalization from the paper “The entropy of the waves and in electrocardiogram and some comments,” by Şengönül et al. Autors: Sevda Atpınar;Zarife Zararsız;Mehmet Şengönül; Appeared in: IEEE Transactions on Fuzzy Systems Publication date: Oct 2017, volume: 25, issue:5, pages: 1168 - 1174 Publisher: IEEE » The Ethereal Nature of Data [MicroBusiness]  Abstract:Explores the etheral nature of documents, both print and data that is stored online via computer and digital systems. Among the old technical files were several stunning vellum assembly drawings of TWTs. Autors: Fred Schindler; Appeared in: IEEE Microwave Magazine Publication date: Oct 2017, volume: 18, issue:6, pages: 20 - 22 Publisher: IEEE » The First IEEE MTT-S Latin America Microwave Conference [Conference Report]  Abstract:Presents information on the First IEEE MTT-S Latin America Microwave Conference. Autors: José E. Rayas-Sánchez;George E. Ponchak; Appeared in: IEEE Microwave Magazine Publication date: Oct 2017, volume: 18, issue:6, pages: 128 - 131 Publisher: IEEE » The History and Benefits of Standardization in Power Distribution Systems [Standards News]  Abstract:The function of electrical power systems is to generate, transmit, and distribute electricity safely and efficiently. An electrical power system can be considered one of the tools for converting and transporting energy. Pipelines transmit gas and water on land, and they can, along with railroads, also transmit oil. However, the only means currently available for transporting energy in the form of electricity is over transmission lines. Standards played an important role in the power industry. Many companies had entered the market in the 1890s, and they all chose their own settings for voltage, frequency, current, and even the symbols used on circuit diagrams. Autors: Daleep Mohla; Appeared in: IEEE Industry Applications Magazine Publication date: Oct 2017, volume: 23, issue:5, pages: 70 - 80 Publisher: IEEE » The Impact of Model-Based Clutter Suppression on Cluttered, Aberrated Wavefronts  Abstract:Recent studies reveal that both phase aberration and reverberation play a major role in degrading ultrasound image quality. We previously developed an algorithm for suppressing clutter, but we have not yet tested it in the context of aberrated wavefronts. In this paper, we evaluate our previously reported algorithm, called aperture domain model image reconstruction (ADMIRE), in the presence of phase aberration and in the presence of multipath scattering and phase aberration. We use simulations to investigate phase aberration corruption and correction in the presence of reverberation. As part of this paper, we observed that ADMIRE leads to suppressed levels of aberration. In order to accurately characterize aberrated signals of interest, we introduced an adaptive component to ADMIRE to account for aberration, referred to as adaptive ADMIRE. We then use ADMIRE, adaptive ADMIRE, and conventional filtering methods to characterize aberration profiles on in vivo liver data. These in vivo results suggest that adaptive ADMIRE could be used to better characterize a wider range of aberrated wavefronts. The aberration profiles’ full-width at half-maximum of ADMIRE, adaptive ADMIRE, and postfiltered data with 0.4- spatial cutoff frequency are 4.0 ± 0.28 mm, 2.8 ± 1.3 mm, and 2.8 ± 0.57 mm, respectively, while the average root-mean square values in the same order are 16 ± 5.4 ns, 20 ± 6.3 ns, and 19 ± 3.9 ns, respectively. Finally, because ADMIRE suppresses aberration, we perform a limited evaluation of image quality using simulations and in vivo data to determine how ADMIRE and adaptive ADMIRE perform with and without aberration correction. Autors: Kazuyuki Dei;Brett Byram; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Oct 2017, volume: 64, issue:10, pages: 1450 - 1464 Publisher: IEEE » The Light Field Attachment: Turning a DSLR into a Light Field Camera Using a Low Budget Camera Ring  Abstract:We propose a concept for a lens attachment that turns a standard DSLR camera and lens into a light field camera. The attachment consists of eight low-resolution, low-quality side cameras arranged around the central high-quality SLR lens. Unlike most existing light field camera architectures, this design provides a high-quality 2D image mode, while simultaneously enabling a new high-quality light field mode with a large camera baseline but little added weight, cost, or bulk compared with the base DSLR camera. From an algorithmic point of view, the high-quality light field mode is made possible by a new light field super-resolution method that first improves the spatial resolution and image quality of the side cameras and then interpolates additional views as needed. At the heart of this process is a super-resolution method that we call iterative Patch- And Depth-based Synthesis (iPADS), which combines patch-based and depth-based synthesis in a novel fashion. Experimental results obtained for both real captured data and synthetic data confirm that our method achieves substantial improvements in super-resolution for side-view images as well as the high-quality and view-coherent rendering of dense and high-resolution light fields. Autors: Yuwang Wang;Yebin Liu;Wolfgang Heidrich;Qionghai Dai; Appeared in: IEEE Transactions on Visualization and Computer Graphics Publication date: Oct 2017, volume: 23, issue:10, pages: 2357 - 2364 Publisher: IEEE » The metrological culture in the context of big data: managing data-driven decision confidence  Abstract:In recent years, data sets are steadily growing in size because of the huge sensing, storage, computation, and transmission capabilities offered at very low cost by current Information Technology systems, which are increasingly driving ubiquitous data acquisition from the empirical world. Moreover, massive amounts of data can be collected very efficiently- sometimes at zero marginal costs—from the internet. The concept of Big Data (BD) epitomizes this phenomenon among the experts and the general public (for an accessible, application-oriented introduction to BD in the broad context of data science, see, e.g., [1]). Autors: Luca Mari;Dario Petri; Appeared in: IEEE Instrumentation & Measurement Magazine Publication date: Oct 2017, volume: 20, issue:5, pages: 4 - 20 Publisher: IEEE » The Metrologist's place is by the machines!  Abstract:Industry 4.0, smart objects, new versions of ISO 9001 and 17025 standards, and so on... massive changes are taking place in companies that, as a result, are learning to be increasingly agile and responsive. It is time for metrology to remodel itself to keep pace. Smart Metrology needs to go beyond the role of ensuring conformity to regulatory standards and traceability to national measurement standards to gain the approval of auditors and focus its energy upon the true essential consideration: the quality of the measurements made within a company! Autors: Jean-Michel Pou; Appeared in: IEEE Instrumentation & Measurement Magazine Publication date: Oct 2017, volume: 20, issue:5, pages: 10 - 29 Publisher: IEEE » The Miniaturization of a Partially 3-D Printed Quadrifilar Helix Antenna  Abstract:In this paper, the design and implementation of a quadrifilar helix antenna are presented where the four arms are 3-D printed. The antenna structure is miniaturized by resorting to a combination of two approaches. The first approach is based on loading the tips of the four helical arms with circular conductive disks. The size and location of these elements directly affect the antenna’s operating frequency. The second miniaturization approach is based on incorporating an FR-4 dielectric material into the vacant space between the four arms of the quadrifilar helix. As a result, the length of the antenna is reduced by a ratio of 43%. The quadrifilar helix antenna is also designed on top of a ground plane with an optimized conical shape and topology. The antenna is partially fabricated using 3-D printing additive technology, where measurements show great agreement with simulated results. Autors: Youssef Tawk;Michel Chahoud;Marwan Fadous;Joseph Costantine;Christos G. Christodoulou; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Oct 2017, volume: 65, issue:10, pages: 5043 - 5051 Publisher: IEEE » The Multidimensional Cramér–Rao–Leibniz Lower Bound for Likelihood Functions With Parameter-Dependent Support  Abstract:One regularity condition for the classical Cramér–Rao lower bound (CRLB) of an unbiased estimator to hold—that the support of the likelihood function (LF) should be independent of the parameter to be estimated—has recently been relaxed to the case of parameter-dependent support as long as the LF is continuous at the boundary of its support. For the case where the LF is not continuous on the boundary of its support, a new modified CRLB—designated the Cramér–Rao–Leibniz lower bound (CRLLB) as it relies on the Leibniz integral rule—has also been presented for the scalar parameter case. The present work derives the multidimensional CRLLB for the case of LF with parameter-dependent support by applying the general Leibniz integral rule to complete the framework of the CRLLB. Autors: Qin Lu;Yaakov Bar-Shalom;Peter Willett;Francesco Palmieri;Fred Daum; Appeared in: IEEE Transactions on Aerospace and Electronic Systems Publication date: Oct 2017, volume: 53, issue:5, pages: 2331 - 2343 Publisher: IEEE » The Optimization for Hyperbolic Positioning of UHF Passive RFID Tags  Abstract:This paper presents a fine-grained positioning method for radio frequency identification (RFID). The proposed method applies hyperbolic positioning to locate ultrahigh frequency passive RFID tags. In our design, finding the tagged object’s location is formulated as an optimization problem. Phase values, collected by the moving antenna, are exploited to achieve the optimal solution. The intuition of hyperbolic positioning lies in that the difference of distances from a target tag to two antennas can be inferred from phases. When integrating hyperbola curves together, optimization method can be performed to achieve the object’s location. Particle swarm optimization is then applied to enhance computational ability. For random phases, polynomial regression is employed to model the relationship between phase values and distances. We implement a prototype of hyperbolic positioning optimization to pinpoint the RFID tag’s location and evaluate its performance in our laboratory environment. Compared with other RFID localization methods, i.e., received signal strength indicator based and phase-based approaches, our design shows greater tolerance to tag diversity and tag orientation.Note to Practitioners—Radio frequency identification (RFID), as a crucial component of the Internet of things, has been widely deployed in many industrial applications ranging from logistics to retail. There are increasing needs for RFID to not only detect whether the tagged object is within the radio range, but also locate the object with high accuracy. Current RFID systems addressing these problems are either expensive or complex to implement. The RFID-based localization method presented in this paper is cost-efficient and computationally inexpensive. We consider using commercial off-the-shelf RFID devices without deployment of the reference tags to locate the target object. The antenna is mounted- on a mobile vehicle to emulate the antenna array. Due to the fact that the target tag lies on the hyperbolic curve with two antennas’ positions as the foci, this paper suggests constructing multiple hyperbolas to determine the target position based on the virtual antenna array. The experimental results demonstrate that the proposed approach is feasible and achieves a median accuracy of 12 cm. Autors: Haishu Ma;Yi Wang;Kesheng Wang;Zongzheng Ma; Appeared in: IEEE Transactions on Automation Science and Engineering Publication date: Oct 2017, volume: 14, issue:4, pages: 1590 - 1600 Publisher: IEEE » The Origin of the High Off-State Current in p-Type Cu2O Thin Film Transistors  Abstract:There is a need for a good quality p-type accumulation-mode thin film transistor (TFT) using a metal oxide semiconducting channel. P-type cuprous oxide (Cu2O) has been proposed as a suitable semiconductor, but such TFTs have suffered from unacceptably high off-state currents. This letter studies the main origin of this high off-state current. Capacitance–voltage characteristics reveal the accumulation of minority carriers (electrons) in the off-state regime (i.e., for a positive gate voltage). The activation energy extracted from the temperature dependence of the drain current as a function of gate voltage shows an abrupt lowering of the activation energy and pinning of the Fermi energy in the off-state region, which is attributed to subgap states at 0.38 eV from the conduction band minimum. This suggests that an electron flow in the off-state causes the high off-state current in p-type Cu2O TFTs and not an inability to deplete the channel of holes. Autors: Sanggil Han;Andrew J. Flewitt; Appeared in: IEEE Electron Device Letters Publication date: Oct 2017, volume: 38, issue:10, pages: 1394 - 1397 Publisher: IEEE » The Regulatory Debate About Energy Storage Systems: State of the Art and Open Issues  Abstract:Energy storage has long bee n lauded as the holy grail of energy technologies. Low-cost energy storage, proponents say, will usher in a new era in power systems, enabling large penetrations of variable renewable energy technologies and reshaping the way electricity networks deliver energy. Autors: Ines Usera;Pablo Rodilla;Scott Burger;Ignacio Herrero;Carlos Batlle; Appeared in: IEEE Power and Energy Magazine Publication date: Oct 2017, volume: 15, issue:5, pages: 42 - 50 Publisher: IEEE » The Role of the Antenna Radiation Pattern in the Performance of a Microwave Tomographic Approach for GPR Imaging  Abstract:Microwave tomography has been exploited as a successful imaging technique for ground penetrating radar (GPR) surveys. However, an “ideal” antenna model (i.e., a filamentary current element) has usually been adopted so far to describe the involved scattering phenomena. In this study, such an assumption is removed, and the effects of a “realistic” antenna are taken into account by means of a customized numerical implementation. Specifically, we provide indications about the reconstruction capabilities expectable when the imaging is performed by using a “directional” wideband transceiver to gather GPR data. Moreover, we discuss to what extent the imaging performance is affected by a priori knowledge of the antenna model. Autors: Davide Comite;Alessandro Galli;Ilaria Catapano;Francesco Soldovieri; Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Publication date: Oct 2017, volume: 10, issue:10, pages: 4337 - 4347 Publisher: IEEE » The Spherical-Actuator-Magnet Manipulator: A Permanent-Magnet Robotic End-Effector  Abstract:A variety of magnetic devices can be manipulated remotely using a single permanent “actuator” magnet positioned in space by a robotic manipulator. This paper describes the spherical-actuator-magnet manipulator (SAMM), which is designed to replace or augment the singularity-prone spherical wrist used by prior permanent-magnet manipulation systems. The SAMM uses three omniwheels to enable holonomic control of the heading of its magnet's dipole and to enable its magnet to be rotated continuously about any axis of rotation. The SAMM performs closed-loop control of its dipole's heading using field measurements obtained from Hall-effect sensors as feedback, combined with modeled dynamics, using an extended Kalman filter. We describe the operation and construction of the SAMM, develop and characterize controllers for the SAMM's spherical magnet, and demonstrate remote actuation of an untethered magnetic device in a lumen using the SAMM. Autors: Samuel E. Wright;Arthur W. Mahoney;Katie M. Popek;Jake J. Abbott; Appeared in: IEEE Transactions on Robotics Publication date: Oct 2017, volume: 33, issue:5, pages: 1013 - 1024 Publisher: IEEE » The story of Invar [Basic Metrology]  Abstract:Material properties are affected by temperature. This can be a major obstacle when, for instance, measuring precise lengths with a metal ruler. If the ruler was calibrated by one laboratory at a reference temperature— say 15°C—but then used at a different temperature in another laboratory, then the calibration certificate might include the value of the ruler's coefficient of thermal expansion, so that a correction could be made for the thermal expansion between the lower and higher temperatures. But what if the second “laboratory” was not a laboratory at all? What if it was an open field and the length to be measured was a 10 km geodesic baseline needed for surveying? This was a serious problem from the late 19th century to the late 20th century. Autors: Richard Davis; Appeared in: IEEE Instrumentation & Measurement Magazine Publication date: Oct 2017, volume: 20, issue:5, pages: 27 - 29 Publisher: IEEE » The Sum Rate of Vector Gaussian Multiple Description Coding With Tree-Structured Covariance Distortion Constraints  Abstract:A single-letter lower bound on the sum rate of multiple description coding with tree-structured distortion constraints is established by generalizing Ozarow’s celebrated converse argument through the introduction of auxiliary random variables that form a Markov tree. For the quadratic vector Gaussian case, this lower bound is shown to be achievable by an extended El Gamal-Cover scheme, yielding a complete characterization of the minimum sum rate. Autors: Yinfei Xu;Jun Chen;Qiao Wang; Appeared in: IEEE Transactions on Information Theory Publication date: Oct 2017, volume: 63, issue:10, pages: 6547 - 6560 Publisher: IEEE » The Watermark Benchmark for Underwater Acoustic Modulation Schemes  Abstract:Watermark is a freely available benchmark for physical-layer schemes for underwater acoustic communications. It allows researchers to test and compare algorithms for the physical layer under realistic and reproducible conditions. The benchmark is a shell around the validated channel simulator Mime, which is driven by at-sea measurements of the time-varying impulse response. The first release of Watermark is issued with a library of channels measured in Norway (two sites), France, and Hawaii, offering three frequency bands (4–8, 10–18, and 32.5–37.5 kHz), single-hydrophone and array receivers, and play times varying from 33 s to 33 min. Autors: Paul A. van Walree;François-Xavier Socheleau;Roald Otnes;Trond Jenserud; Appeared in: IEEE Journal of Oceanic Engineering Publication date: Oct 2017, volume: 42, issue:4, pages: 1007 - 1018 Publisher: IEEE » Theoretical Analysis of Plasmon-Induced Transparency in MIM Waveguide Bragg Grating Coupled With a Single Subradiant Resonator  Abstract:A plasmon-induced transparency (PIT) spectral response in an ultracompact plasmonic structure composed of a metal–insulator–metal waveguide Bragg grating coupled with an air rectangle cavity is proposed, and the corresponding transmission characteristics are investigated theoretically and numerically. By using the transmission line theory (TLT), a remarkable PIT transmission can be proposed in this structure. Moreover, we study the transmission as a function of the coupling distance between the air cavity and insulator layer, and we also discuss the transmission as a function of the thickness of air cavity. To validate the correctness of the TLT results, we have compared them with the finite-difference time-domain method. Both of them agree well with each other. Thus, our results can offer a new possibility and important theory analysis for the designs of the optical switching devices, sensors, and slow light devices in highly integrated optical circuits. Autors: Xin Luo;Xiang Zhai;Lingling Wang;Qi Lin;Jianping Liu; Appeared in: IEEE Photonics Journal Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8 Publisher: IEEE » Theoretical Analysis of the Dynamic Decode Ordering SIC Receiver for Uplink NOMA Systems  Abstract:Instead of successive interference cancellation (SIC) for uplink non-orthogonal multiple access systems with fixed decoding order based on the statistical channel state information (CSI), we focus on decoding with the dynamic order according to the instantaneous CSI. After modeling the channel fluctuation of all the users with different transmit powers and different path losses, a dynamic SIC receiver is proposed based on the instantaneous received power of different users. The outage probability of the proposed system is theoretically analyzed and the closed-form expressions for a three-user system are derived. Simulations are performed to validate the accuracy of the theoretical results. Autors: Yichen Gao;Bin Xia;Kexin Xiao;Zhiyong Chen;Xiaofan Li;Sha Zhang; Appeared in: IEEE Communications Letters Publication date: Oct 2017, volume: 21, issue:10, pages: 2246 - 2249 Publisher: IEEE » Theoretical and Experimental Comparison Between Phase-Shifted PWM and Level-Shifted PWM in a Modular Multilevel SDBC Inverter for Utility-Scale Photovoltaic Applications  Abstract:This paper discusses and compares phase-shifted pulse-width modulation (PS-PWM) and level-shifted PWM (LS-PWM) in a modular multilevel single-delta bridge-cell (SDBC) inverter for utility-scale grid-tied photovoltaic applications. This three-phase SDBC inverter provides the capability of operating even under power-distribution imbalances not only among three clusters, but also among cascaded bridge cells in each cluster. The main focus of this research lies in analyzing the capability of operation under severe power-distribution imbalances and presenting power-balancing methods based on zero-sequence current injection, which result in an extended power-balancing capability. This paper highlights that LS-PWM is superior to PS-PWM in both power-balancing capability and harmonic performance at the ac side of the SDBC inverter when operating under power-distribution imbalances. Experimental results obtained from a three-phase 10-kW downscaled system show good agreement with those from the theoretical analysis. Autors: Paul Sochor;Hirofumi Akagi; Appeared in: IEEE Transactions on Industry Applications Publication date: Oct 2017, volume: 53, issue:5, pages: 4695 - 4707 Publisher: IEEE » Theoretical and Experimental Investigation of Fiber-Ring Laser Intracavity Photoacoustic Spectroscopy (FLI-PAS) for Acetylene Detection  Abstract:An acetylene (C2H2) sensor was developed based on the fiber-ring laser intracavity photoacoustic spectroscopy (FLI-PAS) by incorporating a photoacoustic cell into the fiber-ring laser cavity to obtain the enhanced photoacoustic signal. A detailed theoretical model was constructed to describe the processes involved in FLI-PAS and to understand the factors affecting the sensor performance. Wavelength modulation spectroscopy with the second harmonic detection was implemented to increase the detection signal-to-noise ratio by using a custom-designed fiber Bragg grating wavelength modulator. We used this FLI-PAS sensor for C2H2 detection at 1531.59 nm. With the modulation amplitude and intracavitary power optimized, our sensor achieved a noise equivalent concentration of 36 ppbv at the 118-s integration time and a linear dynamic range of ∼105 . The limitations of the current FLI-PAS sensor were discussed in detail to explore feasible ways for further improvement in sensitivity and linear dynamic range. Autors: Qiang Wang;Zhen Wang;Wei Ren; Appeared in: Journal of Lightwave Technology Publication date: Oct 2017, volume: 35, issue:20, pages: 4519 - 4525 Publisher: IEEE » Theoretical Performance Limit of the IGBT  Abstract:In this paper, an analytical model of insulated gate bipolar transistor (IGBT) on-state voltage () and turn-off loss () is developed to find the optimum solution (minimum power loss) for a given application. With this model, it is found that IGBT on-state voltage is limited by the fact that holes can only flow from the anode to the cathode. The minimum on-state voltage for a Si IGBT with 110- wide drift region is found out to be around 0.835 V at 100 A/cm2 and room temperature. For a given operating frequency and chip size, a tradeoff between on-state voltage and turn-off loss that gives minimum device power loss can be achieved by manipulating the carrier profile in the drift region with an optimum structure design. This minimum device loss decreases mildly with increasing chip size, i.e., a merely 45% loss reduction when the chip size increases from 0.2 to 5 cm2. These results clearly indicate that the performance of an IGBT is not area sensitive. They are encouraging for device manufacturers who wish to reduce the device chip size to lower cost. However, the constraint comes from the device thermal dissipation capabilities which decrease quickly with decreasing chip size. These results are validated with numerical 2-D device simulations for a large variety of device structures, chip size, and operating frequencies (2 to 200 kHz). State-of-the-art IGBT product performance is compared against the theoretical limit indicating there is still substantial room for improvement at low and high frequencies. Autors: Hengyu Wang;Ming Su;Kuang Sheng; Appeared in: IEEE Transactions on Electron Devices Publication date: Oct 2017, volume: 64, issue:10, pages: 4184 - 4192 Publisher: IEEE » Theory of Exceptional Points of Degeneracy in Uniform Coupled Waveguides and Balance of Gain and Loss  Abstract:We present a transmission line theory of exceptional points of degeneracy (EPD) in coupled-mode guiding structures, i.e., a theory that illustrates the characteristics of coupled electromagnetic modes under a special dispersion degeneracy condition, yet unexplored in the contest of gain and loss. We show that coupled transmission lines (CTLs) at radio frequencies having gain (active devices) and loss (e.g., material, radiation) balance exhibit EPDs. We demonstrate the concept of parity-time ()-symmetry in uniform CTLs that involve symmetric gain and loss and how this condition is associated with a second-order EPD. Furthermore, we also demonstrate that -symmetry is not a necessary condition for realizing EPDs, and indeed, we show that EPD is also obtained with asymmetric distributions of gain and loss in uniform CTLs. We further propose potential applications of the EPDs in designing leaky-wave antennas with the capability of beam and directivity control as well as enhanced sensitivity. Operating near such special degeneracy conditions leads to potential performance enhancement in a variety of microwave and optical resonators, antennas, and devices such as distributed oscillators, including lasers, amplifiers, radiating oscillators, pulse compressors, and -switching sensors. Autors: Mohamed A. K. Othman;Filippo Capolino; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Oct 2017, volume: 65, issue:10, pages: 5289 - 5302 Publisher: IEEE » Theory-Guided Data Science: A New Paradigm for Scientific Discovery from Data  Abstract:Data science models, although successful in a number of commercial domains, have had limited applicability in scientific problems involving complex physical phenomena. Theory-guided data science (TGDS) is an emerging paradigm that aims to leverage the wealth of scientific knowledge for improving the effectiveness of data science models in enabling scientific discovery. The overarching vision of TGDS is to introduce scientific consistency as an essential component for learning generalizable models. Further, by producing scientifically interpretable models, TGDS aims to advance our scientific understanding by discovering novel domain insights. Indeed, the paradigm of TGDS has started to gain prominence in a number of scientific disciplines such as turbulence modeling, material discovery, quantum chemistry, bio-medical science, bio-marker discovery, climate science, and hydrology. In this paper, we formally conceptualize the paradigm of TGDS and present a taxonomy of research themes in TGDS. We describe several approaches for integrating domain knowledge in different research themes using illustrative examples from different disciplines. We also highlight some of the promising avenues of novel research for realizing the full potential of theory-guided data science. Autors: Anuj Karpatne;Gowtham Atluri;James H. Faghmous;Michael Steinbach;Arindam Banerjee;Auroop Ganguly;Shashi Shekhar;Nagiza Samatova;Vipin Kumar; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Oct 2017, volume: 29, issue:10, pages: 2318 - 2331 Publisher: IEEE » Thermal Penetration Depth Analysis and Impact of the BEOL Metals on the Thermal Impedance of SiGe HBTs  Abstract:In this letter, we present a detailed investigation on how dynamic thermal phenomena take place in state-of-the-art SiGe HBTs when excited by sinusoidal power dissipation. To give a better insight into the mechanisms leading to the thermal impedance ( decay, we introduce the concept of thermal penetration depth; then, with the help of 3-D thermal simulations, we illustrate its effect on the spatial distribution of the temperature variations within the transistor structure, according to the frequency of operation. In order to experimentally analyze the impact on a real device, dedicated HBT structures are designed; they consist of multi-finger SiGe HBTs realized in B55 technology from STMicroelectronics, for which modifications are made in the back-end-of-line (BEOL) metallization or in the transistor layout, increasing its deep trench isolation enclosed area. For these transistors, measurements are carried out in the frequency range 10kHz–1GHz; the results show that the metal connections configuration in the BEOL or layout modifications can considerably impact the decay at low frequencies. An identical trend is instead measured above 1–2 MHz, demonstrating that at higher frequencies just the region close to the heat source is concerned by dynamic thermal phenomena. Autors: Rosario D’Esposito;Suresh Balanethiram;Jean-Luc Battaglia;Sébastien Frégonèse;Thomas Zimmer; Appeared in: IEEE Electron Device Letters Publication date: Oct 2017, volume: 38, issue:10, pages: 1457 - 1460 Publisher: IEEE » Thermal Response Time of Media in Heat-Assisted Magnetic Recording  Abstract:Heat-assisted magnetic recording (HAMR) promises to deliver higher storage areal density than the current perpendicular magnetic recording product. A laser is introduced to the HAMR system to heat magnetic media to reduce the media coercivity. The thermal response of the media becomes very critical for the success of the magnetic writing process. The study of thermal response time in HAMR relies on the setup configurations, such as laser spot sizes, the way that laser energy is delivered to media and the media structures. In this paper, the thermal response time of HAMR media under three different heating methods is systematically investigated through experiments and numerical analysis. A lumped model is built to simplify the heat conduction problem to understand the difference in thermal responses under various experimental conditions. Dominant layers are identified under those experimental conditions. The transient thermal response is mainly determined by the dominant layers. Engineering the dominant layers helps the most in optimizing the thermal performance of the media. Our study clearly suggests that for HAMR systems, optimizing the thermal properties of the heat sink layer is the key to reducing variations in the transient thermal process resulting from changes in the linear speed. Autors: Shaomin Xiong;Robert Smith;Na Wang;Dongbo Li;Erhard Schreck;Sripathi Canchi;Qing Dai; Appeared in: IEEE Transactions on Magnetics Publication date: Oct 2017, volume: 53, issue:10, pages: 1 - 6 Publisher: IEEE » Thermal Tuning of High-$T_{c}$Superconducting Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$Terahertz Metamaterial  Abstract:We introduce a class of low-loss subwavelength resonators and report the first demonstration of a high-temperature ( ) superconducting BiSrCaCuO (BSCCO) terahertz (THz) metamaterial. The numerical simulations and analytical calculations are performed to study the electromagnetic response of the subwavelength BSCCO split-ring resonators (SRRs) to the incident photons with energies below the superconducting gap energy. A transition of resonance strength is observed as a dip in resonance frequency for temperatures below BSCCO . To interpret the transmission spectra, resonance switching, and frequency tuning of SRRs, we calculate the temperature dependent complex permittivity and surface impedance of a 200 nm thick unpatterned slightly underdoped BSCCO thin film. We compare the resonance tunability of SRRs made of the extremely disorder superconductor (BSCCO) with metamaterials made of a weakly disorder superconductor YBa2Cu3O7 (YBCO) and show that the resonance quality and frequency tuning are comparable for these two metamaterials. Our results may be useful for THz emitters and detectors developments, for instance, by integration of SRRs with BSCCO THz emitters and microstrip antennas, the device functionalities such as polarization, emission pattern directivity, and output power could be controlled and improved. Autors: S. Kalhor;M. Ghanaatshoar;T. Kashiwagi;K. Kadowaki;M. J. Kelly;K. Delfanazari; Appeared in: IEEE Photonics Journal Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8 Publisher: IEEE » Thermal-Aware Energy Management of an HPC Data Center via Two-Time-Scale Control  Abstract:This paper presents a two-time-scale control method to optimize the energy consumption of high-performance-computing data centers through dynamic frequency scaling of processors, tasks assignment, and cooling supplement. First, the steady and dynamical models of the data center are built, which reflect the computational interactions and thermal relationship among the components of the data center. Next, the energy minimization problem for processing a parallel task is divided into two parts that correspond to the steady thermal model and the dynamic thermal one. Then, the problem is solved in a two-time-scale manner, i.e., the optimization of task assignment and processing frequency is considered in steady thermal environment, and the optimization of cooling supplement is achieved in dynamic thermal environment. Finally, simulations of a real task trace are carried out, which demonstrate that the proposed method can significantly improve energy efficiency while guaranteeing the thermal constraints of the data center. Autors: Qiu Fang;Jun Wang;Qi Gong;Mengxuan Song; Appeared in: IEEE Transactions on Industrial Informatics Publication date: Oct 2017, volume: 13, issue:5, pages: 2260 - 2269 Publisher: IEEE » Thermoresistive Effect for Advanced Thermal Sensors: Fundamentals, Design Considerations, and Applications  Abstract:Microelectromechanical systems sensors have been intensively developed utilizing various physical concepts, such as piezoresistive, piezoelectric, and thermoresistive effects. Among these sensing concepts, the thermoresistive effect is of interest for a wide range of thermal sensors and devices, thanks to its simplicity in implementation and high sensitivity. The effect of temperature on the electrical resistance of some metals and semiconductors has been thoroughly investigated, leading to the significant growth and successful demonstration of thermal-based sensors, such as temperature sensors, convective accelerometers and gyroscopes, and thermal flow sensors. In this paper, we review the fundamentals of the thermoresistive effect in metals and semiconductors. We also discuss the influence of design and fabrication parameters on the thermoresistive sensitivity. This paper includes several desirable features of thermoresistive sensors and recent developments in these sensors are summarized. This review provides insights into how it is affected by various parameters, and useful guidance for industrial designers in terms of high sensitivity and linearity and fast response. [2017-0022] Autors: Toan Dinh;Hoang-Phuong Phan;Afzaal Qamar;Peter Woodfield;Nam-Trung Nguyen;Dzung Viet Dao; Appeared in: Journal of Microelectromechanical Systems Publication date: Oct 2017, volume: 26, issue:5, pages: 966 - 986 Publisher: IEEE » Thinned Array Design With Minimum Number of Transducers for Multibeam Imaging Sonar  Abstract:A large number of transducers employed in the multibeam imaging sonar array significantly increases the hardware complexity, costs, and computational load. Although a great amount of work has been done to minimize the number of transducers in the array, one can verify that these methods do not provide optimal results when applied to the case of multiple beams. In this paper, a novel thinning method is proposed for multiple-beam conditions where the number of transducers is minimized by an iterative process. Optimal common transducers’ positions are selected by a wind-driven optimization (WDO) algorithm, and transducers’ weights are optimized by convex optimization in order to suppress the peak sidelobe level (PSLL). The performance of the proposed method is evaluated via simulations and experiments. Results show that the method is applicable to the minimization of the number of transducers under hundreds of beam conditions, and consequently reduces the complexity of the imaging sonar system with imaging performance still acceptable. Autors: Weijie Xia;Xue Jin;Fawang Dou; Appeared in: IEEE Journal of Oceanic Engineering Publication date: Oct 2017, volume: 42, issue:4, pages: 892 - 900 Publisher: IEEE » Three advances make magnetic tape more than a memory [News]  Abstract:In the age of flash memory and DNAbased data storage, magnetic tape sounds like an anachronism. But the workhorse storage technology is racing along. Scientists at IBM Research say they can now store 201 gigabits per square inch on a special "sputtered" tape made by Sony Storage Media Solutions. The palm-size cartridge, into which IBM scientists squeezed a kilometer-long ribbon of tape, could hold 330 terabytes of data, or roughly 330 million books' worth. By comparison, the largest solid-state drive, made by Seagate, is twice as big and can store 60 TB, while the largest hard disk can store only 12 TB. IBM's best commercial tape cartridge, which began shipping this year, holds 15 TB. Autors: Prachi Patel; Appeared in: IEEE Spectrum Publication date: Oct 2017, volume: 54, issue:10, pages: 9 - 11 Publisher: IEEE » Three Bands Substrate Integrated Waveguide Cavity Spatial Filter With Different Polarizations  Abstract:A frequency-selective surface on circular substrate integrated waveguide (SIW) cavities with three pass bands is presented. The main performance of the proposed structure is three Ka-bands spatial filtering with different polarized outputs in each passband which is achieved by combining of enhanced Jerusalem and Gangbuster surfaces based upon circular SIW cavities. The horizontal polarized incident waves enter the circular SIW cavities and excite their dominant modes. Then, the excited cavities emit horizontal and vertical polarized waves through the enhanced Jerusalem and Gangbuster slots on the opposite side of cavities. The proposed structure optimization and evaluation are performed by CST Microwave Studio. The compact size and sharp roll-off in stop bands are other advantages of the proposed structure. Autors: M. Sharifian Mazraeh Mollaei;S. H. Sedighy; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Oct 2017, volume: 65, issue:10, pages: 5628 - 5632 Publisher: IEEE » Three-Axis Atomic Magnetometer Employing Longitudinal Field Modulation  Abstract:A three-axis atomic magnetometer employing longitudinal field modulation is demonstrated theoretically and experimentally. The operational condition of this magnetometer is that the longitudinal z-component of the external magnetic field is dominant, which is achieved by applying a bias magnetic field. The longitudinal z-component of the external magnetic field is extracted from the modulation frequency, which tracks the resonance frequency, and the transverse x- and y- components are, respectively, obtained from the quadrature and the in-phase signals of a lock-in amplifier. Through feedback control, the magnitude and direction of an external magnetic field can be measured in real time, and an excellent orthogonality of the three-axis magnetometer response is obtained. By optimizing the parameters of this three-axis magnetometer, a longitudinal field sensitivity of 0.3 and a transverse field sensitivity of 2 are achieved. Autors: Zhichao Ding;Jie Yuan;Guangfeng Lu;Yingying Li;Xingwu Long; Appeared in: IEEE Photonics Journal Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9 Publisher: IEEE » Three-Dimensional Inversion of GREATEM Data: Application to GREATEM Survey Data From Kujukuri Beach, Japan  Abstract:Studies have shown that the grounded electrical-source airborne transient electromagnetics (GREATEM) method is a promising method for investigating resistivity structures in coastal areas, in addition to those in inaccessible areas such as volcanoes, mountains, and deep forest cover. To expand the application field of the GREATEM system, a three-dimensional (3-D) resistivity model that considers large lateral resistivity variations is required. In this paper, we present a frequency-domain 3-D electromagnetic inversion approach that can be applied to time-domain data from GREATEM. In the frequency-domain approach, TEM data are Fourier-transformed using a smooth-spectrum inversion method, and the recovered frequency response is then inverted. To deal with a large number of grids and a wide range of frequencies in airborne datasets, a method for approximating sensitivities is introduced for efficient 3-D inversion. Approximate sensitivities are derived by replacing adjoint secondary electric fields with those computed in the previous iteration. These sensitivities can reduce computation time without significant loss of accuracy. First, we verified both our forward and inversion solutions. Then, we applied this approach to GREATEM survey data from Kujukuri Beach, central Japan. The inverted results of the field data were well fitted with previous study results in the Kujukuri area, suggesting applicability of this inversion approach for constructing 3-D resistivity models from GREATEM field survey data in the future. Autors: Sabry Abdallah;Toru Mogi;Hee Joon Kim; Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Publication date: Oct 2017, volume: 10, issue:10, pages: 4321 - 4327 Publisher: IEEE » Three-Dimensional Printed Fluid-Filled Electrostatic Rotating Machine Designed with Conformal Mapping Methods  Abstract:Recently, fluid-filled electrostatic machines demonstrated specific and volumetric torque densities that hold promise to be competitive with electromagnetic machines in niche applications, e.g., air-cooled, low-speed, and direct-drive machines. These demonstrations of variable capacitance (or elastance, which is the dual of reluctance) machines were nonoptimized from an electrostatics perspective as their geometry was heavily constrained by manufacturability issues. This paper proposes a semi-analytical design method that combines conformal mapping techniques with finite element analysis, leading to more optimal electrostatic machine geometries. Parametric sweeps of key relative dimensions establish best practices/guidelines for design. A fractional horsepower proof of concept machine was designed using the new approach and was built using stereolithographic three-dimensional printing to circumvent manufacturing constraints. The machine is mostly plastic, plated with conductor, and is, therefore, lightweight. This manufacturing approach suggests that a machine can be injected molded or cast in a single step. Measurements of the prototype demonstrate a torque density of 0.31 Nm/L and specific torque density of 0.22 Nm/kg, comparable with similar size NEMA frame fractional horsepower induction motors. Also the Nm/kV2 of the prototype machine is two orders of magnitude greater than prior nonliquid-filled work. Autors: Baoyun Ge;Aditya N. Ghule;Daniel C. Ludois; Appeared in: IEEE Transactions on Industry Applications Publication date: Oct 2017, volume: 53, issue:5, pages: 4348 - 4359 Publisher: IEEE » Three-Operator Proximal Splitting Scheme for 3-D Seismic Data Reconstruction  Abstract:The proximal splitting algorithm, which reduces complex convex optimization problems into a series of smaller subproblems and spreads the projection operator onto a convex set into the proximity operator of a convex function, has recently been introduced in the area of signal processing. Following the splitting framework, we propose a novel three-operator proximal splitting (TOPS) algorithm for 3-D seismic data reconstruction with both singular value decomposition (SVD)-based low-rank constraint and curvelet-domain sparsity constraint. Compared with the well-known forward–backward splitting (FBS) method, our proposed TOPS algorithm can be flexibly employed to recover a signal satisfying double convex constraints simultaneously, such as low-rank constraint and sparsity constraint used in this letter. We have used both synthetic and field data examples to demonstrate the superior performance of the TOPS method over traditional SVD-based low-rank method and curvelet-domain sparsity method based on the FBS framework. Autors: Yufeng Wang;Hui Zhou;Shaohuan Zu;Weijian Mao;Yangkang Chen; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Oct 2017, volume: 14, issue:10, pages: 1830 - 1834 Publisher: IEEE » Time for a 5G Technology Assessment and Road Map? [President's Column]  Abstract:Perhaps what many of us find most exciting are the outlines of next-generation (5G) application spaces that would be feasible if we could unlock the great open spaces in the millimeter-wave (mmW) bands for mobile communications, allowing real-time transfer of not only conventional data but also high-definition video and haptic (tactile and kinesthetic) information on millisecond time scales. Those spaces include applications in augmented reality, which relies on telecommunications to transfer high-definition video to a server where it is processed, augmented, and then sent back to the user in real time. The automotive industry is not just betting on systems that allow cars to negotiate the streets based on sensing the immediate surroundings; they envision globally aware autonomous automobiles that leverage immediate feedback from all the surrounding autonomous systems to maximize throughput and increase speeds, while driving more closely together and more safely than human drivers or their locally aware counterparts. And, of course, the public safety and other sectors are eagerly awaiting advances in communications that will allow robots to transfer not only real-time, high-definition video but haptic feedback as they fight fires, safely perform surgery, and carry out other functions to protect their human counterparts in the field. These applications are expected to create a US$3 trillion per year global market, and the companies and countries that can successfully unlock the mmW spectrum will immediately gain a critical advantage in deployment over their competitors. Autors: Dylan Williams; Appeared in: IEEE Microwave Magazine Publication date: Oct 2017, volume: 18, issue:6, pages: 10 - 14 Publisher: IEEE
» Time Synchronization in WSNs With Random Bounded Communication Delays
 Abstract:Recently, it was pointed out that many popular consensus-based time synchronization algorithms, such as Average TimeSynch (ATS), are all divergent in a network with arbitrarily small random communication delays under any interconnection topology. This note proposes a least-squares estimation-based time synchronization (LSTS for short) algorithm. This algorithm modifies the ATS algorithm in relative drift estimator, low-pass filter, and consensus protocol. By analyzing the mathematic model of the algorithm, it is proved that LSTS ensures asymptotic convergence of the drift estimation and boundedness of the global time synchronization error under random bounded communication delays if the network topology satisfies some connectedness conditions. Autors: Yu-Ping Tian; Appeared in: IEEE Transactions on Automatic Control Publication date: Oct 2017, volume: 62, issue:10, pages: 5445 - 5450 Publisher: IEEE
» Time–Frequency Packing Applied to Cost-Effective IM/DD Transmission Based on Directly Modulated VCSEL
 Abstract:Potential of directly modulated vertical cavity surface emitting lasers (VCSELs), widely employed for low-cost and energy-efficient intradata center transmissions, is here studied for transmissions up to access/metro scenarios. In particular, the manuscript refers to long-wavelength VCSELs for intensity modulation/direct detection (IM/DD) on–off keying transmission over standard single-mode fiber (SSMF). The intent of this paper primarily consists of demonstrating information rate and fiber reach enhancement in potentially uncooled environments or with relaxed thermal management requirements through the use of time–frequency packing (TFP) technique in a VCSEL-based transmission. TFP has been applied here to IM/DD transmission for the first time, although not in a multiple channel system. The digital signal processing unit implementation is clearly simplified with respect to coherent systems (no frequency synchronization and no phase error recovery), where TFP was firstly introduced, as it only takes into account the photo-detected signal intensity, regardless of the phase information. On the other hand, the signal processing is here more complex than in a traditional IM/DD system. Through the use of a commercial C-band 4 G VCSEL, net information rate up to 12.5 and 11.2 Gb/s has been measured for 25 and 45 km of SSMF, respectively, in an unamplified optical link and with power budget equal to 19 and 16 dB, respectively. The transmission is intrinsically polarization independent and wavelength independent and tolerance to temperature increase up to 60 °C has been analyzed together with energy consumption. Autors: Antonio Malacarne;Francesco Fresi;Gianluca Meloni;Tommaso Foggi;Luca Potì; Appeared in: Journal of Lightwave Technology Publication date: Oct 2017, volume: 35, issue:20, pages: 4384 - 4391 Publisher: IEEE
» Time-Domain Arithmetic Logic Unit With Built-In Interconnect
 Abstract:This paper describes a low-power 1-GHz 4-bit time-domain arithmetic logic unit (ALU) targeting hardware accelerator. This ALU relies on the time-domain computation based on digital-to-time converter, digitally controlled oscillator, time-to-digital converter, and successive approximation register analog-to-digital converter. The interconnect bandwidth limitation addressed by the time-domain and voltage-domain encoding to improve the spectrum efficiency by . Encoder and decoders are part of the computation, and that results in 1-GHz operational speed in 65-nm CMOS consuming 17.75 mW only. Compared to the conventional approach, the proposed time-domain computation achieves significantly lower power and latency for similar area and resolution. Autors: Aurangozeb;AKM Delwar Hossain;Can Ni;Quazi Sharar;Masum Hossain; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Oct 2017, volume: 25, issue:10, pages: 2828 - 2841 Publisher: IEEE
» Timer-Based Demodulator for AM Sensor Signals Applied to an Inductive Displacement Sensor
 Abstract:This paper proposes a novel method for demodulating low-frequency amplitude-modulated (AM) signals provided by sensors. The method relies on a digital timer that carries out the demodulation and digitization simultaneously, without requiring a rectifier, a mixer, a low-pass filter, or an analog-to-digital converter. This timer-based demodulator extracts the amplitude of the AM signal by measuring the period of a reference signal that is altered by the AM signal itself. The period measurement undergoes a deviation that carries information about the amplitude of the AM signal. The feasibility and also the limitations, such as the nonlinearity and aliasing effects, of this novel demodulator are proved theoretically and experimentally. The concept is also applied to measure an inductive displacement sensor in a range of ±30 mm. A nonlinearity error of 0.5% full-scale span and a resolution of 9 bits are achieved for an overall measuring time of 100 ms. Autors: Ferran Reverter;Manel Gasulla; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Oct 2017, volume: 66, issue:10, pages: 2780 - 2788 Publisher: IEEE
» Tissue Acoustoelectric Effect Modeling From Solid Mechanics Theory
 Abstract:The acoustoelectric (AE) effect is a basic physical phenomenon, which underlies the changes made in the conductivity of a medium by the application of focused ultrasound. Recently, based on the AE effect, several biomedical imaging techniques have been widely studied, such as ultrasound-modulated electrical impedance tomography and ultrasound current source density imaging. To further investigate the mechanism of the AE effect in tissue and to provide guidance for such techniques, we have modeled the tissue AE effect using the theory of solid mechanics. Both bulk compression and thermal expansion of tissue are considered and discussed. Computation simulation shows that the muscle AE effect result, conductivity change rate, is with 4.3-MPa peak pressure, satisfying the theoretical value. Bulk compression plays the main role for muscle AE effect, while thermal expansion makes almost no contribution to it. In addition, the AE signals of porcine muscle are measured at different focal positions. With the same magnitude order and the same change trend, the experiment result confirms that the simulation result is effective. Both simulation and experimental results validate that tissue AE effect modeling using solid mechanics theory is feasible, which is of significance for the further development of related biomedical imaging techniques. Autors: Xizi Song;Yexian Qin;Yanbin Xu;Pier Ingram;Russell S. Witte;Feng Dong; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Oct 2017, volume: 64, issue:10, pages: 1583 - 1590 Publisher: IEEE
» Topology Analysis of Wireless Power Transfer Systems Manufactured Via Inkjet Printing Technology
 Abstract:The potential of inkjet printing technology (IjP) for the fabrication of coils for biomedical applications in inductively coupled power transfer systems is studied in terms of needed compensations, bifurcation phenomena, and power transfer efficiency. The effect of using coils manufactured with IjP in the secondary side has been analyzed by studying the effect of the increase in internal resistance. The present study makes it possible to select the best topology depending on the load impedance, the coupling coefficient, and coil design. In terms of the compensations needed at the primary side, IjP does not significantly affect the behavior of the system; however, the series-series topology is preferable since the compensating capacitance is independent from the internal resistance. In terms of bifurcation, a more restricted condition is obtained for parallel compensated secondary circuits. There is a decrease on the power transfer efficiency due to the increase of the internal resistance introduced by IjP. However, it is important to select the best topology according to the application since the decrease could be from 63% to only 6%. It is concluded that IjP is a promising fabrication technique for coils for biomedical applications. Autors: Iñaki Ortego-Isasa;Kami Pars Benli;Félix Casado;Juan Ignacio Sancho;Daniel Valderas; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Oct 2017, volume: 64, issue:10, pages: 7749 - 7757 Publisher: IEEE
» Topology and Modulation Scheme of a Three-Level Third-Harmonic Injection Indirect Matrix Converter
 Abstract:The matrix converter is a direct ac-ac power conversion topology. To improve the output waveform quality of the conventional matrix converter and overcome the drawbacks of the neutral-point clamped matrix converters such as the neutral-point voltage balancing issue, the limited control range of the input reactive power and the need for strict synchronization in the modulations of the rectification and inversion stages, a three-level third-harmonic injection indirect matrix converter, and a neutral-point voltage balancing algorithm are proposed. The topology consists of a line-commutated input voltage selector, a three-level inverter and a third-harmonic injection circuit, where the split dc source voltage of the inverter is formed by two input line-line voltages. Furthermore, by adopting the active power filtering technique and utilizing the third-harmonic injection circuit to compensate the neutral-point current, the neutral-point potential is balanced without extra control effort. In addition, except the advantages such as bidirectional power flow, sinusoidal input-output currents, and multilevel output voltages, the synchronization in modulations is eliminated, and the control range of the input reactive power is extended significantly. Finally, the functionality and effectiveness of the proposed methods are verified by simulations and experimental results. Autors: Hui Wang;Mei Su;Yao Sun;Guanguan Zhang;Jian Yang;Weihua Gui;Jianghua Feng; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Oct 2017, volume: 64, issue:10, pages: 7612 - 7622 Publisher: IEEE
» Torque Capability Enhancement of Dual Three-Phase PMSM Drive With Fifth and Seventh Current Harmonics Injection
 Abstract:A method for enhancing torque capability of a dual three-phase permanent magnet synchronous machine (PMSM) based on conventional dual three-phase drive system by injecting the fifth and seventh current harmonics without any hardware re-configuration is proposed in this paper. Compared with the third current harmonic injection, which is commonly used to enhance the torque capability of dual three-phase machine, the two isolated neutral points of each set of single three-phase windings do not need to be reconnected to the middle point of dc-link capacitors or an additional power switching bridge to provide flowing path for zero-sequence current. Further, no additional current sensors are required to obtain the feedback of zero-sequence current to regulate it effectively. For a prototype dual three-phase PMSM, the average torque increases approximately by 9% at the cost of 0.56% increase in the 12th harmonic torque ripple. The effectiveness of the torque capability enhancement is confirmed by experiments. Autors: Yashan Hu;Z. Q. Zhu;Milijana Odavic; Appeared in: IEEE Transactions on Industry Applications Publication date: Oct 2017, volume: 53, issue:5, pages: 4526 - 4535 Publisher: IEEE
» Toward High-Power All-Fiber 2–5 μm Supercontinuum Generation in Chalcogenide Step-Index Fiber
 Abstract:In this  paper, a high-power spectrally flat 2–5 μm supercontinuum (SC) laser is reported in a piece of As2S3 chalcogenide step-index fiber. A fluoride fiber-based SC laser which spans from 2–4.2 μm is used as the pump light. Two pump coupling systems between the fluoride and As2S3 fibers, one based on aspheric lens coupling and the other using all-fiber mechanical splicing are investigated. With the setup of aspheric lens coupling, the obtained SC laser has a 10 dB spectral bandwidth of 3000 nm spanning from 2050 to 5050 nm, corresponding to an average power of 57.6 mW. While with the all-fiber mechanical splicing, the 10 dB spectral bandwidth of the SC laser shrinks slightly, spanning from 2140 to 4980 nm range, but the average output power is further scaled to a record power of 97.1 mW. It is found that the dominant nonlinearities for continuous spectral broadenings in the As2 S3 fiber are self-phase modulation and stimulated Raman scattering in the normal dispersion regime. This paper presents an all-fiber mid-infrared SC laser with spectrum beyond 5 μm for the first time. It also offers a practical solution for robust and reliable high power 2–5 μm broadband fiber laser. Autors: Ke Yin;Bin Zhang;Jinmei Yao;Zhen Cai;Guangchen Liu;Jing Hou; Appeared in: Journal of Lightwave Technology Publication date: Oct 2017, volume: 35, issue:20, pages: 4535 - 4539 Publisher: IEEE
» Toward Near-Ground Localization: Modeling and Applications for TOA Ranging Error
 Abstract:Near-ground localization is a special type of localization scenario that is widely considered in both academic and industry. In this communication, with considering the multipath condition in near-ground environments, we conducted field measurements and proposed an antenna height-dependent time of arrival (TOA) ranging error model. Experiment results show that TOA distance measurement errors accord with Gaussian distribution, and its mean and variance are directly related with antenna height and communication distance. Based on the proposed TOA ranging error model, Cramer–Rao lower bound under typical scenarios have been calculated, and localization performance simulation has been studied. The experiment results indicate that the proposed TOA ranging error model has significant theoretical and practical application values. Autors: Cheng Xu;Jie He;Xiaotong Zhang;Po-Hsuan Tseng;Shihong Duan; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Oct 2017, volume: 65, issue:10, pages: 5658 - 5662 Publisher: IEEE
» Toward Novel Wearable Pyroelectric Temperature Sensor for Medical Applications
 Abstract:Knowledge of an amputees’ residual limb skin temperature is considered to be of particular importance as an indicator of tissue health. Temperature within the prosthetic socket typically varies over the range 25 °C to 35 °C and this warm, confined environment causes sweating which creates favourable conditions for both the growth of bacteria and an increased risk of tissue breakdown. With this in mind a wearable sensor for the real-time measurement of temperature variations at the prosthetic socket/liner interface is under development and a proof of concept prototype is presented. The sensor exploits the large pyroelectric effect present in ferroelectric lead zirconate titanate PbZrx(Ti(1–x))O3 (PZT) and has several inherent advantages over other methods of temperature sensing. The sensing element is a low cost commercially available thick-film PZT device. Mathematical models are developed to describe the sensor immitance and response to temperature change, and both the clamped and unclamped capacitances are investigated over the range 20 °C to 40 °C. Sensor characteristics were found to be dominated by the clamped dielectric constant and operation under short-circuit conditions is found to offer a constant sensor gain over the temperature range of interest. Autors: Alan Davidson;Arjan Buis;Ivan Glesk; Appeared in: IEEE Sensors Journal Publication date: Oct 2017, volume: 17, issue:20, pages: 6682 - 6689 Publisher: IEEE
» Toward Physiology-Aware DASH: Bandwidth-Compliant Prioritized Clinical Multimedia Communication in Ambulances
 Abstract:The ultimate objective of medical cyber-physical systems is to enhance the safety and effectiveness of patient care. To ensure safe and effective care during emergency patient transfer from rural areas to center tertiary hospitals, reliable and real-time communication is essential. Unfortunately, real-time monitoring of patients involves transmission of various clinical multimedia data including videos, medical images, and vital signs, which requires use of mobile network with high-fidelity communication bandwidth. However, the wireless networks along the roads in rural areas range from 4G to 2G to low speed satellite links, which poses a significant challenge to transmit critical patient information. In this paper, we present a bandwidth-compliant criticality-aware system for transmission of massive clinical multimedia data adaptive to varying bandwidths during patient transport. Model-based clinical automata are used to determine the criticality of clinical multimedia data. We borrow concepts from DASH, and propose physiology-aware adaptation techniques to transmit more critical clinical data with higher fidelity in response to changes in disease, clinical states, and bandwidth condition. In collaboration with Carle's ambulance service center, we develop a bandwidth profiler, and use it as proof of concept to support our experiments. Our preliminary evaluation results show that our solutions ensure that most critical patient's clinical data are communicated with higher fidelity. Autors: Mohammad Hosseini;Yu Jiang;Richard R. Berlin;Lui Sha;Houbing Song; Appeared in: IEEE Transactions on Multimedia Publication date: Oct 2017, volume: 19, issue:10, pages: 2307 - 2321 Publisher: IEEE
» Toward QoE-Assured 4K Video-on-Demand Delivery Through Mobile Edge Virtualization With Adaptive Prefetching
 Abstract:Internet video streaming applications have been demanding more bandwidth and higher video quality, especially with the advent of virtual reality and augmented reality appli-cations. While adaptive strea ming protocols like MPEG-DASH (dynamic adaptive streaming over HTTP) allows video quality to be flexibly adapted, e.g., degraded when mobile network condition deteriorates, this is not an option if the application itself requires guaranteed 4K quality at all time. On the other hand, conventional end-to-end transmission control protocol (TCP) has been struggling in supporting 4K video delivery across long-distance Internet paths containing both fixed and mobile network segments with heterogeneous characteristics. In this paper, we present a novel and practically feasible system architecture named MVP (mobile edge virtualization with adaptive prefetching), which enables content providers to embed their content intelligence as a virtual network function into the mobile network operator's infrastructure edge. Based on this architecture, we present a context-aware adaptive video prefetching scheme in order to achieve quality of experience (QoE)-assured 4K video on demand (VoD) delivery across the global Internet. Through experiments based on a real LTE-A network infrastructure, we demonstrate that our proposed scheme is able to achieve QoE-assured 4K VoD streaming, especially when the video source is located remotely in the public Internet, in which case none of the state-of-the-art solutions is able to support such an objective at global Internet scale. Autors: Chang Ge;Ning Wang;Gerry Foster;Mick Wilson; Appeared in: IEEE Transactions on Multimedia Publication date: Oct 2017, volume: 19, issue:10, pages: 2222 - 2237 Publisher: IEEE
» Toward Seamless Multiview Scene Analysis From Satellite to Street Level
 Abstract:In this paper, we discuss and review how combined multiview imagery from satellite to street level can benefit scene analysis. Numerous works exist that merge information from remote sensing and images acquired from the ground for tasks such as object detection, robots guidance, or scene understanding. What makes the combination of overhead and street-level images challenging are the strongly varying viewpoints, the different scales of the images, their illuminations and sensor modality, and time of acquisition. Direct (dense) matching of images on a per-pixel basis is thus often impossible, and one has to resort to alternative strategies that will be discussed in this paper. For such purpose, we review recent works that attempt to combine images taken from the ground and overhead views for purposes like scene registration, reconstruction, or classification. After the theoretical review, we present three recent methods to showcase the interest and potential impact of such fusion on real applications (change detection, image orientation, and tree cataloging), whose logic can then be reused to extend the use of ground-based images in remote sensing and vice versa. Through this review, we advocate that cross fertilization between remote sensing, computer vision, and machine learning is very valuable to make the best of geographic data available from Earth observation sensors and ground imagery. Despite its challenges, we believe that integrating these complementary data sources will lead to major breakthroughs in Big GeoData. It will open new perspectives for this exciting and emerging field. Autors: Sébastien Lefèvre;Devis Tuia;Jan Dirk Wegner;Timothée Produit;Ahmed Samy Nassaar; Appeared in: Proceedings of the IEEE Publication date: Oct 2017, volume: 105, issue:10, pages: 1884 - 1899 Publisher: IEEE
» Toward Socially Aware Robot Navigation in Dynamic and Crowded Environments: A Proactive Social Motion Model
» Toward Synchronization in Networks With Nonlinear Dynamics: A Submodular Optimization Framework
 Abstract:Synchronization underlies phenomena including memory and perception in the brain, coordinated motion of animal flocks, and stability of the power grid. These synchronization phenomena are often modeled through networks of phase-coupled oscillating nodes. Heterogeneity in the node dynamics, however, may prevent such networks from achieving the required level of synchronization. In order to guarantee synchronization, external inputs can be used to pin a subset of nodes to a reference frequency, while the remaining nodes are steered toward synchronization via local coupling. In this paper, we present a submodular optimization framework for selecting a set of nodes to act as external inputs in order to achieve synchronization from a desired set of initial states. We derive threshold-based sufficient conditions for synchronization, and then prove that these conditions are equivalent to constraints on monotone submodular functions over partition matroids. Based on this connection, we map the sufficient conditions for synchronization to constraints on submodular functions, leading to efficient algorithms with provable optimality bounds for selecting input nodes. We illustrate our approach via numerical studies of synchronization in power systems. Autors: Andrew Clark;Basel Alomair;Linda Bushnell;Radha Poovendran; Appeared in: IEEE Transactions on Automatic Control Publication date: Oct 2017, volume: 62, issue:10, pages: 5055 - 5068 Publisher: IEEE
» Toward the Development of Secure Underwater Acoustic Networks
 Abstract:Underwater acoustic networks (UANs) have been recognized as an enabling technology for various applications in the maritime domain. The wireless nature of the acoustic medium makes UANs vulnerable to various malicious attacks, yet, limited consideration has been given to security challenges. In this paper, we outline a hybrid architecture that incorporates aspects of physical layer security, software defined networking, node cooperation, cross-layering, context-awareness, and cognition. The proposed architecture envisions strategies at the node as well as at the network level that adapt to environmental changes, the status of the network and the possible array of attacks. Several examples of attacks and countermeasures are discussed while deployment and functionality issues of the proposed architecture are taken into consideration. This work is not intended to represent a whatsoever proven solution but mainly to suggest future research directions to the scientific community working in the area of UANs. Autors: Chhagan Lal;Roberto Petroccia;Konstantinos Pelekanakis;Mauro Conti;João Alves; Appeared in: IEEE Journal of Oceanic Engineering Publication date: Oct 2017, volume: 42, issue:4, pages: 1075 - 1087 Publisher: IEEE
» Towards Optimal Connectivity on Multi-Layered Networks
 Abstract:Networks are prevalent in many high impact domains. Moreover, cross-domain interactions are frequently observed in many applications, which naturally form the dependencies between different networks. Such kind of highly coupled network systems are referred to as multi-layered networks, and have been used to characterize various complex systems, including critical infrastructure networks, cyber-physical systems, collaboration platforms, biological systems, and many more. Different from single-layered networks where the functionality of their nodes is mainly affected by within-layer connections, multi-layered networks are more vulnerable to disturbance as the impact can be amplified through cross-layer dependencies, leading to the cascade failure to the entire system. To manipulate the connectivity in multi-layered networks, some recent methods have been proposed based on two-layered networks with specific types of connectivity measures. In this paper, we address the above challenges in multiple dimensions. First, we propose a family of connectivity measures (SubLine) that unifies a wide range of classic network connectivity measures. Third, we reveal that the connectivity measures in the SubLine family enjoy diminishing returns property, which guarantees a near-optimal solution with linear complexity for the connectivity optimization problem. Finally, we evaluate our proposed algorithm on real data sets to demonstrate its effectiveness and efficiency. Autors: Chen Chen;Jingrui He;Nadya Bliss;Hanghang Tong; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Oct 2017, volume: 29, issue:10, pages: 2332 - 2346 Publisher: IEEE
» Track-Before-Detect Strategies for Radar Detection in G0-Distributed Clutter
 Abstract:This paper considers target detection via dynamic-programming based track-before-detect (DP-TBD) for radar systems. The clutter is modeled usingenlr G0 distribution, which is usually used to model clutter received from high-resolution radars and radars working at small grazing angles. Two target models, namely, Swerling 0 and 1 models, are considered to capture the radar cross section changes over time. DP-TBD techniques that integrate amplitude suffer from significant performance loss in this case due to the high likelihood of target-like outliers. In this paper, the log-likelihood ratio (LLR) is used in the integration process of DP-TBD, taking the place of amplitude, to enhance radar detection performance. The expressions for the LLR for the above target models are derived first. However, neither of them has a closed-form solution. In order to reduce the complexity of evaluating the LLR, efficient but accurate approximation methods are proposed. Then the approximated LLR is used in the integration process of DP-TBD. Simulations are used to examine the efficiency of the approximation methods as well as the performances of different DP-TBD strategies. Autors: Wei Yi;Haichao Jiang;Thia Kirubarajan;Lingjiang Kong;Xiaobo Yang; Appeared in: IEEE Transactions on Aerospace and Electronic Systems Publication date: Oct 2017, volume: 53, issue:5, pages: 2516 - 2533 Publisher: IEEE
» Transient and Stable Profiles During Anisotropic Wet Etching of Quartz
 Abstract:This paper presents a comprehensive analysis of the transient (short-term) and stable (long-term) cross-sectional profiles of elongated trenches formed by anisotropic wet etching on Z-cut quartz. Because all quartz planes parallel (and near-parallel) to the [0001] direction display very low (and dissimilar) etch rates, dramatically different profiles are observed depending on the particular mask alignment of the trench edges with respect to the substrate. Nevertheless, the profiles can be easily predicted by identifying the location of a few key orientations for each trench profile. This is done by measuring the etch rate distribution on a hemispherical specimen of quartz and locating the local maxima of the (signed) curvature of the etch rate for all planes parallel to the trench edges. We show that this generalizes the traditional method based on locating the local minima of the etch rate. Furthermore, our approach enables capturing accurately the etch front by applying the traditional Wulff–Jaccodine construction on just a few key orientations, thus greatly simplifying the use of that method and highlighting the simplicity and importance of the proposed key orientations. A maximum positive curvature recognition method is developed based on applying the moving average filter to the calculation of the first, second, and third order derivatives of the etch rate. This allows quick locating of all orientations that will appear on the short-term and long-term profiles, even for the complete etch rate distribution, thus helping the design of desired profiles with vertical (or nearly vertical) side walls. Furthermore, the proposed maximum positive curvature recognition method accurately explains the formation of complex facets on square cavities, as well as on the top, middle, and bottom regions of micro-needle arrays etched on quartz Z-cuts. [2017-0025] Autors: Yan Xing;Miguel A. Gosálvez;Hui Zhang;Yuan Li;Xiaoli Qiu; Appeared in: Journal of Microelectromechanical Systems Publication date: Oct 2017, volume: 26, issue:5, pages: 1063 - 1072 Publisher: IEEE
» Transients of Modal-Power Distribution in Multimode Solid-Core W-Type Photonic Crystal Fibers
 Abstract:Spatial transients of the modal power distribution are reported for a varied configuration of air holes in the inner cladding of multimode solid-core photonic crystal fibers. Such inner cladding forms an intermediate fiber layer seen in W-type fibers with the layer's own effective refractive index due to the distinct size and/or spacing of air holes in it. We show how the modal distribution transients along the fiber depend on the number of rings in the inner cladding containing the distinct arrangement of air holes, and on the size and spacing of such holes in addition to the type of launch condition (excitation). Autors: Milan S. Kovačević;Ljubica Kuzmanović;Ana Simović;Svetislav Savović;Alexandar Djordjevich; Appeared in: Journal of Lightwave Technology Publication date: Oct 2017, volume: 35, issue:20, pages: 4352 - 4357 Publisher: IEEE
» Transmission Rate Optimization of Full-Duplex Relay Systems Powered by Wireless Energy Transfer
 Abstract:We consider a system where a source node communicates with a destination node with the assistance of a wireless energy-powered full-duplex relay node. The relay node splits its received signal into two components for energy harvesting and information decoding, respectively, and forwards the decoded information using a portion of the harvested energy. To maximize the end-to-end transmission rate, the power splitting factor and energy consumption proportion are jointly optimized for the relay with a single transmit antenna in the presence of self-interference. Furthermore, for the relay with multiple transmit antennas, a suboptimal relay beamformer is first designed and the power splitting factor and energy consumption proportion are then jointly optimized. Finally, the asymptotic transmission rate is analyzed with a large number of transmit antennas. Simulation results are provided to demonstrate that the proposed schemes offer significant rate gain compared with some typical reference schemes, irrespective of the residual self-interference level. Especially, by employing a large number of source or relay transmit antennas, the wireless energy-powered relay system is capable of cutting its energy consumption significantly. Autors: Long Zhao;Xiaodong Wang;Taneli Riihonen; Appeared in: IEEE Transactions on Wireless Communications Publication date: Oct 2017, volume: 16, issue:10, pages: 6438 - 6450 Publisher: IEEE
 Abstract:In this paper, the problem of the waveform design for colocated multiple-input multiple-output (MIMO) radars is considered in two parts. In the first part, we design transmit waveform in order to approximate the desired beampattern with low number of samples in the transmitter. Unlike the traditional waveform design methods, in our solution, waveforms are designed for a specific number of samples. Also, the constant envelope constraint that is an important practical constraint is considered. In the second part, we jointly design the transmit waveform and receive filter by a sequential algorithm, considering a priori information of target and interference angle locations. We have evaluated the performance of the proposed algorithms via numerical simulations and shown that the proposed algorithm in the first part is able to approximate the desired beampattern with low number of samples. Also, our method in the second part achieves better signal-to-interference-plus-noise ratio performance compared with the existing active sensing array methods (e.g., phased-array and correlated MIMO radars). Autors: Sadjad Imani;Mohammad Mahdi Nayebi;Seyed Ali Ghorashi; Appeared in: IEEE Transactions on Aerospace and Electronic Systems Publication date: Oct 2017, volume: 53, issue:5, pages: 2178 - 2186 Publisher: IEEE
» Transmitter Linearization Adaptable to Power-Varying Operation
 Abstract:This paper presents the design of a power-scalable digital predistorter (DPD) for transmitter architectures. The target is to accomplish the joint compensation of impairments due to the I/Q modulator and nonlinearities associated with the power amplifier, and procure a maintained linearization performance in a range of average working operation levels. The identification method for the linearizer parameters enriches the standard least-squares procedure with a synergistic integration with sparsity-based model pruning strategies. The method has been tested with a general complex-valued Volterra model applied to the linearization of two communications transmitters operating at 3.6 GHz. The linearizers designed for the two transmitters effectively provide the joint compensation of the nonlinear behavior. In addition to their good performance in terms of adjacent channel power ratio, the DPDs exhibit a wide range of power-varying adaptation. Autors: Carlos Crespo-Cadenas;María J. Madero-Ayora;Javier Reina-Tosina;Juan A. Becerra-González; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Oct 2017, volume: 65, issue:10, pages: 3624 - 3632 Publisher: IEEE
» Transport of Liposome Encapsulated Drugs in Voxelized Computational Model of Human Brain Tumors
 Abstract:There are many obstacles in the transport of chemotherapeutic drugs to tumor cells that lead to irregular and non-uniform uptake of drugs inside tumors. The study of these transport problems will help with accurate prediction of drug transport and optimizing treatment strategy. To this end, liposome mediated drug delivery has emerged as an excellent anticancer therapy due to its ability to deliver drugs at site of action and reducing the chances of side effects to the healthy tissues. In this paper, a computational fluid dynamics (CFD) model based on realistic vasculature of human brain tumor is presented. This model utilizes dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) data to account for heterogeneity in tumor vasculature. Porosity of the interstitial space inside the tumor and normal tissue is determined voxel-wise by processing the DCE-MRI images by general tracer kinetic model (GTKM). The CFD model is applied to predict transport of two different types of liposomes (stealth and conventional) in tumors. The amount of accumulated liposomes is compared with accumulated free drug (doxorubicin) in the interstitial space. Simulation results indicate that stealth liposomes accumulate more and remain for longer periods of time in tumors as compared with conventional liposomes and free drug. The present model provides us a qualitative and quantitative examination on the transport and deposition of liposomes as well as free drugs in actual human brain tumors. Autors: A. Bhandari;A. Bansal;A. Singh;N. Sinha; Appeared in: IEEE Transactions on NanoBioscience Publication date: Oct 2017, volume: 16, issue:7, pages: 634 - 644 Publisher: IEEE
» Trap-Tolerant Device Geometry for InAs/Si pTFETs
 Abstract:The influence of channel quantization and interface traps on the performance of InAs/Si pTFETs is analyzed, and a device geometry is predicted which is least sensitive to trap-assisted tunneling (TAT). The good agreement between simulated and measured transfer characteristics validates the reliability of the simulation setup. Simulations show that TAT degrades the sub-threshold swing (SS) of the tunnel field effect transistor (TFET) and that channel quantization reduces its ON-current. The same simulation setup is used to find the device geometry which is least susceptible to interface traps. Scaling down the nanowire diameter below 20 nm inhibits TAT at the oxide/InAs interface. Furthermore, aligning the gate edge with the InAs/Si hetero-junction reduces the degradation of the SS caused by TAT at the hetero-interface. In this way, a gate-aligned InAs/Si nanowire TFET with diameter ~20 nm can deliver sub-thermal sub-threshold swing even in the unavoidable presence of oxide- and hetero-interface traps. Autors: Saurabh Sant;Andreas Schenk; Appeared in: IEEE Electron Device Letters Publication date: Oct 2017, volume: 38, issue:10, pages: 1363 - 1366 Publisher: IEEE
» Trends in Data Locality Abstractions for HPC Systems
 Abstract:The cost of data movement has always been an important concern in high performance computing (HPC) systems. It has now become the dominant factor in terms of both energy consumption and performance. Support for expression of data locality has been explored in the past, but those efforts have had only modest success in being adopted in HPC applications for various reasons. them However, with the increasing complexity of the memory hierarchy and higher parallelism in emerging HPC systems, locality management has acquired a new urgency. Developers can no longer limit themselves to low-level solutions and ignore the potential for productivity and performance portability obtained by using locality abstractions. Fortunately, the trend emerging in recent literature on the topic alleviates many of the concerns that got in the way of their adoption by application developers. Data locality abstractions are available in the forms of libraries, data structures, languages and runtime systems; a common theme is increasing productivity without sacrificing performance. This paper examines these trends and identifies commonalities that can combine various locality concepts to develop a comprehensive approach to expressing and managing data locality on future large-scale high-performance computing systems. Autors: Didem Unat;Anshu Dubey;Torsten Hoefler;John Shalf;Mark Abraham;Mauro Bianco;Bradford L. Chamberlain;Romain Cledat;H. Carter Edwards;Hal Finkel;Karl Fuerlinger;Frank Hannig;Emmanuel Jeannot;Amir Kamil;Jeff Keasler;Paul H J Kelly;Vitus Leung;Hatem Ltai Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Oct 2017, volume: 28, issue:10, pages: 3007 - 3020 Publisher: IEEE
» Triple-Mode Ceramic Cavity Filters With Wide Spurious-Free Performance
 Abstract:A triple-mode silver-plated ceramic cavity filter with wide spurious-free response is presented. It uses single mode ceramic slabs as interfacing resonators with the cube to give wide spurious-free performance up to 4 GHz for an 1800-MHz base station filter. Three square apertures at the slab-cube interface give simple and flexible control of transmission zero placement while maintaining low insertion loss. The parallel nature of the slab-to-cube coupling allows a simple cuboid structure without chamfers or intermode coupling elements. A seven-pole filter in the DCS-1800 transmit band is built using a slab-slab-cube-slab-slab structure and measured. Along with wide spurious-free performance, the filter achieves around 1 dB of band edge insertion loss with more than 50 dB of attenuation, 20 MHz from the band edges, and from an 11-cm3 package. The near band performance shows all of the seven poles in the return loss. The insertion loss is 1.1 dB on the low side (1805 MHz), 1.0 dB on the high side (1880 MHz), and 0.6 dB at the band center. The wideband response shows more than 40 dB of attenuation up to the frequency 3.7 GHz. Autors: David R. Hendry;Amin M. Abbosh; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Oct 2017, volume: 65, issue:10, pages: 3780 - 3788 Publisher: IEEE
» Triple-Mode, Hybrid-Storage, Energy Harvesting Power Management Unit: Achieving High Efficiency Against Harvesting and Load Power Variabilities
 Abstract:This paper presents a triple-mode, hybrid storage, energy-harvesting power management unit (EH PMU) that interfaces a photovoltaic cell, a regulated load, and a rechargeable battery. The objective is to maximize the end-to-end conversion efficiency of the EH PMU against temporal mismatch and variabilities of harvesting and load power. To minimize the involvement (charging or discharging) of a battery in the voltage conversion process, the proposed hybrid energy storage employs both battery and capacitor, which increases transient energy buffering capability and reduces the overall power conversion loss. Measurement results with 65-nm test chips show that the proposed EH PMU can achieve up to 2.2 higher end-to-end conversion efficiency than the conventional dual-mode architectures under testing cases emulating realistic load and harvesting power variabilities. We also devised a framework for the system design to guide capacitor sizing, buffering voltage range selection, and end-to-end efficiency tradeoffs. Autors: Jiangyi Li;Jae-sun Seo;Ioannis Kymissis;Mingoo Seok; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Oct 2017, volume: 52, issue:10, pages: 2550 - 2562 Publisher: IEEE
» Tristate Memory Cells Using Double-Peaked Fin-Array III–V Tunnel Diodes Monolithically Grown on (001) Silicon Substrates
 Abstract:We demonstrate functional tristate memory cells using multipeaked GaAs/InGaAs fin-array tunnel diodes grown on exact (001) Si substrates. On-chip connection of single-peaked tunnel diode arrays produces I–V characteristics with multiple negative-differential resistance regions. We designed and fabricated two types of tristate memory cells. In one design, a double-peaked tunnel diode was used as the drive, and a reverse-biased single-peaked tunnel diode was used as the load. In the other design, the tristate memory cell was realized by the series connection of two forward-biased single-peaked tunnel diodes. Autors: Yu Han;Qiang Li;Kei May Lau; Appeared in: IEEE Transactions on Electron Devices Publication date: Oct 2017, volume: 64, issue:10, pages: 4078 - 4083 Publisher: IEEE
» Truncated Predictor Control of Lipschitz Nonlinear Systems With Time-Varying Input Delay
 Abstract:This note deals with control design for Lipschitz nonlinear systems with time-varying input delay. Based on a truncated prediction of the system state over the delay period, both a state and an output feedback control law are constructed. Within the framework of Lyapunov-Krasovskii functionals, a set of conditions are identified under which the closed-loop system under either the state feedback or the output feedback law is globally asymptotically stable at the origin. A numerical example is included to demonstrate the effectiveness of the proposed designs. Autors: Zongyu Zuo;Zongli Lin;Zhengtao Ding; Appeared in: IEEE Transactions on Automatic Control Publication date: Oct 2017, volume: 62, issue:10, pages: 5324 - 5330 Publisher: IEEE
» TSV-Based 3-D ICs: Design Methods and Tools
 Abstract:Vertically integrated circuits (3-D ICs) may revitalize Moore’s law scaling which has slowed down in recent years. 3-D stacking is an emerging technology that stacks multiple dies vertically to achieve higher transistor density independent of device scaling. They provide high-density vertical interconnects, which can reduce interconnect power and delay. Moreover, 3-D ICs can integrate disparate circuit technologies into a single chip, thereby unlocking new system-on-chip architectures that do not exist in 2-D technology. While 3-D integration could bring new architectural opportunities and significant performance enhancement, new thermal, power delivery, signal integrity and reliability challenges emerge as power consumption grows, and device density increases. Moreover, the significant expansion of CPU design space in 3-D requires new architectural models and methodologies for design space exploration (DSE). New design tools and methods are required to address these 3-D-specific challenges. This keynote paper focuses on the state of the art, ongoing advances and future challenges of 3-D IC design tools and methods. The primary focus of this paper is TSV-based 3-D ICs, although we also discuss recent advances in monolithic 3-D ICs. The objective of this paper is to provide a unified perspective on the fundamental opportunities and challenges posed by 3-D ICs especially from the context of design tools and methods. We also discuss the methodology of co-design to address more complicated and interdependent design problems in 3-D IC, and conclude with a discussion of the remaining challenges and open problems that must be overcome to make 3-D IC technology commercially viable. Autors: Tiantao Lu;Caleb Serafy;Zhiyuan Yang;Sandeep Kumar Samal;Sung Kyu Lim;Ankur Srivastava; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Oct 2017, volume: 36, issue:10, pages: 1593 - 1619 Publisher: IEEE
» Tunable and Broadband Microwave Frequency Comb Generation Using Optically Injected Semiconductor Laser Nonlinear Dynamics
 Abstract:Based on an optically injected semiconductor laser (OISL) operating at period-one (P1) nonlinear dynamical state, tunable and ultrabroadband microwave frequency combs (MFCs) are generated experimentally through further current-modulating the OISL. First, by introducing an injection light with an injection power of mW, whose wavelength is identical to the central wavelength of a free-running distributed feedback semiconductor laser, the OISL can be driven into P1 state with a fundamental frequency of GHz. Next, further modulating the OISL with a modulation frequency of GHz and a modulation power of = 22.0 dBm, an MFC with a bandwidth of 59.4 GHz within a 10 dB amplitude variation is experimentally obtained, and the single sideband phase noise at offset frequency 10 kHz for all comb lines contained within the bandwidth is below −95.0 dBc/Hz. Finally, through varying the modulation frequency, the MFCs with different comb spacing can be obtained, and the influences of relevant operation parameters on the performances of the generated MFCs have been analyzed. Autors: Yue-Nan Li;Li Fan;Guang-Qiong Xia;Zheng-Mao Wu; Appeared in: IEEE Photonics Journal Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 7 Publisher: IEEE
» Tunable Gold Nanorods Q-Switcher for Pulsed Er-Doped Fiber Laser
 Abstract:We prepared the gold nanorods (GNRs) via seed-mediated growth method, and fabricated the fiber-compatible saturable absorption device with it. We found that the nonlinear absorption behavior of the fiber-compatible GNRs saturable absorber can be tuned by introducing an external modulation laser. With the modulating power varying from 0 to 100 mW, the modulation depth of the saturable absorber could be tuned from 22.85% to 17.91%. Based on the all-optical modulation method with GNRs, the pulse width and repetition rate tunable Q-switched pulses can be delivered from an erbium-doped fiber laser. Autors: Guobao Jiang;Yu Jin;Lili Miao;Lin Du;Zhe Kang;Bin Huang;Chujun Zhao;Shuangchun Wen; Appeared in: IEEE Photonics Journal Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9 Publisher: IEEE
» TurboQuad: A Novel Leg–Wheel Transformable Robot With Smooth and Fast Behavioral Transitions
 Abstract:This report is on the design, control strategy, implementation, and performance evaluation of a novel leg–wheel transformable robot called TurboQuad, which can perform fast gait/mode coordination and transitions in wheeled mode, in legged trotting, and in legged walking while in motion. This functionality was achieved by including two novel setups in the robot that were not included in its predecessor, Quattroped. First, a new leg–wheel mechanism was used, in which the leg/wheel operation and its in situ transition can be driven by the same set of motors, so the actuation system and power can be utilized efficiently. Second, a bio-inspired control strategy was applied based on the central pattern generator and coupled oscillator networks, in which the gait/mode generation, coordination, and transitions can be integrally controlled. The robot was empirically built and its performances in the described three gaits/modes as well as the transitions among them were experimentally evaluated and will be discussed in this paper. Autors: Wei-Hsi Chen;Hung-Sheng Lin;Yun-Meng Lin;Pei-Chun Lin; Appeared in: IEEE Transactions on Robotics Publication date: Oct 2017, volume: 33, issue:5, pages: 1025 - 1040 Publisher: IEEE
» Two New Families of Two-Weight Codes
 Abstract:We construct two new infinite families of trace codes of dimension , over the ring , with , when is an odd prime. They have the algebraic structure of abelian codes. Their Lee weight distribution is computed by using Gauss sums. By Gray mapping, we obtain two infinite families of linear -ary codes of respective lengths and . When is singly even, the first family gives five-weight codes. When is odd and , the first family yields -ary two-weight codes, which are shown to be optimal by application of the Griesmer bound. The second family consists of two-weight codes that are shown to be optimal, by the Griesmer bound, whenever and , or and . Applications to secret sharing schemes are given. Autors: Minjia Shi;Yue Guan;Patrick Solé; Appeared in: IEEE Transactions on Information Theory Publication date: Oct 2017, volume: 63, issue:10, pages: 6240 - 6246 Publisher: IEEE
» Two-Dimensional Reverse-Time Migration Applied to GPR With a 3-D-to-2-D Data Conversion
 Abstract:Reverse-time migration (RTM) has shown its advantages over other conventional migration algorithms for ground-penetrating radar (GPR) imaging. RTM is preferred to be implemented in the computationally attractive 2-D domain, whereas a real measurement can only be conducted in a 3-D domain. Thus, we propose an asymptotic 3-D-to-2-D data conversion filter in the frequency domain for preprocessing of the recorded data for 2-D RTM. The accuracy of the data conversion filter is verified by two numerical tests on a homogeneous and a layered model. Then, we evaluate the effectiveness of the data conversion filter on the imaging result of 2-D RTM, which is applied to simulated multioffset GPR data from a buried pipe model. With the filter, subsurface image by the 2-D RTM matches better with the 3-D RTM result especially in the aspect of phase congruency. Therefore, we conclude that this data conversion filter is necessary for 2-D RTM. We also conducted a laboratory experiment on a volcanic ash pit using a multiinput–multioutput GPR system, which is adopted on the Chang-E 5 lunar exploration lander and works in a stationary mode. The 3-D-to-2-D data conversion filter is applied to the measured multioffset GPR data before the 2-D RTM. The imaging results demonstrate that three marble slabs buried at different depths up to 2 m are clearly imaged. Autors: Hai Liu;Zhijun Long;Bo Tian;Feng Han;Guangyou Fang;Qing Huo Liu; Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Publication date: Oct 2017, volume: 10, issue:10, pages: 4313 - 4320 Publisher: IEEE
» Two-Side State-Aided Bit-Flipping Decoding of Generalized Low Density Parity Check Codes
 Abstract:A modified bit-flipping (BF) decoding algorithm is proposed for hard-decoding of generalized low- density parity-check codes over binary channels. This approach introduces an extra bit between the variable nodes and constraint nodes representing the decision reliability of each node. The local decoding failure is also analyzed to provide a reasonable treatment for the most of its causes. The approach is not in the direction of constructing codes with minimum trapping sets, but to reduce their effect in the decoder at a cost of little increase in the resources. The algorithm, which is called two-side state-aided BF, is shown by simulations to outperform previous BF algorithms in terms of error performance. Autors: Sherif Elsanadily;Ashraf Mahran;Osama Elghandour; Appeared in: IEEE Communications Letters Publication date: Oct 2017, volume: 21, issue:10, pages: 2122 - 2125 Publisher: IEEE
» Two-Stage Focusing Algorithm for Highly Squinted Synthetic Aperture Radar Imaging
 Abstract:Highly squinted synthetic aperture radar (SAR) data focusing is a challenging problem with difficulty to correct the severe range-azimuth coupling and motion errors. Squint minimization processing with the range-walk correction is widely adapted to simplify the decoupling processing, while it destructs the azimuth-shift invariance of conventional SAR transfer function. In this paper, a two-stage focusing algorithm (TSFA) is proposed to generate a focused imagery for the highly squinted airborne SAR. In the proposed algorithm, conventional range cell migration correction and azimuth matched filtering are performed and a fine focusing stage is established to correct the azimuth variance. In the fine focusing procedure, the coarse-focused image is divided into azimuth blocks to accommodate the correction of azimuth-variant residual range migration and phase terms. Moreover, precise motion compensation is embedded into the TSFA procedure to form an accurate airborne SAR imagery, which may be called the extended TSFA. In order to balance the processing precision and computational load, optimal selection of block size is investigated in detail. Both simulated and real measured airborne SAR data sets are used to validate the proposed approaches. Autors: Lei Zhang;Guanyong Wang;Zhijun Qiao;Hongxian Wang;Ligang Sun; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Oct 2017, volume: 55, issue:10, pages: 5547 - 5562 Publisher: IEEE
» Two-Stage Reranking for Remote Sensing Image Retrieval
 Abstract:Image reranking is a popular postprocessing method for remote sensing image retrieval (RSIR), which aims at enhancing the initial retrieval performance. In general, it takes either users’ opinions or the relationships between images into consideration to find an optimal reranked list based on the initial retrieved results. In this paper, we present a reranking method for improving RSIR, which is named two-stage reranking (TSR). Suppose the -nearest neighbors of a query RS image have been obtained by the initial retrieval. The first step of our TSR is to edit these neighbors using the editing scheme. A handful of informative and representative RS images are selected by the active learning algorithm, and their binary labels are provided by the users relative to the query image. Then, a binary classifier is trained using the selected RS images and their labels to classify the rest of the neighbors. Finally, both classification results and rank information in the initial retrieval results are considered to decide which neighbor should be excluded. In the next step, the remaining RS images are reranked by the proposed reranking scheme, i.e., multisimilarity fusion reranking. Both the user’s experience and image relationships are taken into account in TSR to ensure the performance of the reranking. The efficiency and the robustness of our method are validated by experiments conducted on two different types of RS images. Compared with the existing visual reranking approaches, our method achieves improved performance. Autors: Xu Tang;Licheng Jiao;William J. Emery;Fang Liu;Dan Zhang; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Oct 2017, volume: 55, issue:10, pages: 5798 - 5817 Publisher: IEEE
 Abstract:In this paper, we consider a surveillance radar equipped with an electronically scanned antenna and study the performance of a two-step sequential detection procedure, where, for each resolution cell, a second observation is taken if a reliable decision cannot be made after the first one. At the design stage, we optimize the available degrees of freedom (namely, dwell time and detection thresholds) so as to maximize the detection rate (DR), defined as the average number of detections from a target per unit of time, under a constraint on the false alarm rate (FAR), which is the average number of false alarms per unit of time from the inspected area. This is motived by the fact that DR and FAR, beside of being per se meaningful figures of merit for parameter tuning, allow a fair performance comparison among detection strategies with different scanning policies. Examples are presented to illustrate the effects of this design philosophy under the two relevant situations of a slowly fluctuating and a fast-fluctuating target response, also in the presence of clutter. Autors: Emanuele Grossi;Marco Lops;Luca Venturino; Appeared in: IEEE Transactions on Aerospace and Electronic Systems Publication date: Oct 2017, volume: 53, issue:5, pages: 2199 - 2213 Publisher: IEEE
» UEP Constructions of Quasi-Cyclic Low-Density Parity-Check Codes via Masking
 Abstract:In this paper, the algebraic constructions of quasi-cyclic low-density parity-check (QC-LDPC) codes with the unequal error protection (UEP) property are considered. A criterion for constructing such codes via the masking technique is proposed, based on which explicit conditions on the base parity-check matrices and masking matrices to achieve UEP are provided. We also give three specific constructions of UEP QC-LDPC codes. Furthermore, a sufficient condition to ensure strict UEP is presented. Simulation results demonstrate the superiority of our constructed codes over time-sharing schemes. The constructed codes also have competitive error performance against randomly constructed equal-error-protection LDPC codes and irregular UEP LDPC codes designed based on the degree distribution. Autors: Chi-Jen Wu;Chung-Hsuan Wang;Chi-chao Chao; Appeared in: IEEE Transactions on Information Theory Publication date: Oct 2017, volume: 63, issue:10, pages: 6271 - 6294 Publisher: IEEE
» Ultra-Wideband Low-Loss Switch Design in High-Resistivity Trap-Rich SOI With Enhanced Channel Mobility
 Abstract:In this paper, the stress memorization technique (SMT) effects upon ultra-wideband RF switch performance are investigated for the first time. Low insertion loss (IL), high isolation, ultra-wideband (dc to 50 GHz) single-pole double-throw (SPDT), and single-pole four-throw (SP4T) switches designed with commercial 0.13- high-resistivity (HR) trap-rich SOI technology with/without SMT are presented and investigated. 2.5 V nMOS transistor () with low from GF 130RFSOI PDK is used. It is found that channel mobility of switch transistor is improved by SMT and thus switch performance can be further improved. Moreover, the impact of transistor channel length, which has dominant effects on both IL and isolation of the switches, under different gate bias on switch performance are also studied and verified experimentally. Low measured IL of less than 2.1 dB and good isolation of better than 27 dB from dc to 50 GHz are obtained for the SPDT switch. For SP4T switch, the measured IL of less than 2.6 dB and isolation of better than 27 dB are achieved from dc to 35 GHz. The active chip areas of designed SPDT and SP4T switches are compact with size of only and , respectively. Autors: Bo Yu;Kaixue Ma;Fanyi Meng;Kiat Seng Yeo;Parthasarathy Shyam;Shaoqiang Zhang;Purakh Raj Verma; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Oct 2017, volume: 65, issue:10, pages: 3937 - 3949 Publisher: IEEE
» Ultra-Wideband Microstrip Line-to-Microstrip Line Transition in Multilayer LCP Substrate at Millimeter-Wave Frequencies
 Abstract:In this letter, an ultrawideband microstrip line (MSL)-to-MSL transition in multilayer liquid crystal polymer (LCP) substrate is presented for millimeter-wave applications. The proposed transition consists of three circuit layers and three LCP layers. The MSLs’ signal lines are in the top circuit layer, while their grounds are distributed in the inner and bottom layers, respectively, and are connected using through vias. Full-wave simulation reveals an insertion loss of less than 1.1 dB for the proposed transition from dc to 110 GHz. To experimentally demonstrate this design, its back-to-back transition was fabricated and characterized. The measured insertion loss and reflection of the back-to-back transition are less than 2.5 and −13 dB below 110 GHz, respectively, showing a good agreement with the simulated data. Autors: Yifei Zhang;Fuquan Wang;Shouyuan Shi;Richard D. Martin;Peng Yao;Dennis W. Prather; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Oct 2017, volume: 27, issue:10, pages: 873 - 875 Publisher: IEEE
» Ultracompact ESD Protection With BIMOS-Merged Dual Back-to-Back SCR in Hybrid Bulk 28-nm FD-SOI Advanced CMOS Technology
 Abstract:The main purpose of this paper is to introduce an ultracompact device for electrostatic discharge (ESD) protection based on a bipolar metal oxide silicon (BIMOS) transistor merged with a dual back-to-back silicon-controlled rectifier (SCR) for bulk and for ultrathin body box fully depleted (FD)-silicon on insulator (SOI) advanced CMOS technologies in the hybrid bulk thanks to process co-integration. It is well known that ESD protection is a challenge for IC in advanced CMOS technology. In this paper, an optimized solution is described through the concept, design, 3-D technology computer aided design (TCAD) simulation, and silicon characterization in 28-nm FD-SOI in hybrid bulk. Measurements are done thanks to transmission line pulsed (TLP), very fast TLP and dc behavior. Moreover, the overvoltage is investigated through very fast transient characterization system measurements. It demonstrates a promising candidate to protect against ESD event and to develop new ESD network dedicated to system on chip. Autors: Philippe Galy;Johan Bourgeat;Nicolas Guitard;Jean-Daniel Lise;David Marin-Cudraz;Charles-Alexandre Legrand; Appeared in: IEEE Transactions on Electron Devices Publication date: Oct 2017, volume: 64, issue:10, pages: 3991 - 3997 Publisher: IEEE
» Ultrahigh Purcell Factor, Improved Sensitivity, and Enhanced Optical Force in Dielectric Bowtie Whispering-Gallery-Mode Resonators
 Abstract:We propose and theoretically investigate an all-dielectric bowtie whispering-gallery-mode (WGM) resonator which consists of two tip-to-tip coupled semiconductor nanorings with triangular cross section separated by low refractive index material gap. Mode splitting of symmetric WGM and antisymmetric WGM is observed and analyzed. Due to extremely field enhancements by the “slot” and “tip” effects, strong localization of light in the gap of symmetric WGMs leads to ultrasmall modal volume of . This value is two orders of magnitude smaller than that in toroidal microresonator which is the typical WGM microcavity with tight mode confinement. Importantly, large amount of light confined in the gap in bowtie WGM resonator not only suppresses the radiation loss (radiation-loss-related quality factor is above ), but also makes it as an ideal platform for Purcell effect enhancement, ultrasensitive sensing, and optical trapping of nanoparticles. Calculation results show that Purcell factor can reach to at room temperature when assuming quantum dots or atoms placed in the gap. Refractive index sensitivity is improved to 700 nm/RIU as compared with conventional slot waveguide with rectangular cross section. The optical gradient force is greatly enhanced and allows efficient trapping of single nanoscale particle with diameter of 5 nm even at a relatively large gap of 100 nm. Autors: Qijing Lu;Xiaogang Chen;Hongqin Yang;Xiang Wu;Shusen Xie; Appeared in: IEEE Photonics Journal Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10 Publisher: IEEE
» Ultrahigh Suppression Broadband Polarization Splitter Based on an Asymmetrical Directional Coupler
 Abstract:Polarization-beam-splitters with both broadband operation window and high extinction ratio are highly desirable in optical communication systems. In this paper, a compact noncascaded-directional-couplers PBS with an ultrahigh extinction ratio and low excess loss is proposed. The PBS utilizes an asymmetrical directional coupling structure consisted of a TE-pass-polarizer waveguide and a TE- and TM-pass waveguide. The simulation results show that the extinction ratio is up to 35.41 dB and the excess loss is only 0.11 dB around the central wavelength 1550 nm for both polarizations (TE and TM). Meanwhile, when the extinction ratio is 30, 25, and 20 dB, the corresponding bandwidth is 72, 145, and 188 nm, respectively. Also, the EL is 1 and 0.5 dB in a bandwidth of ∼73 and ∼48 nm, respectively. A fabrication tolerance of ±10 nm for the waveguide width is also achieved. Autors: Can Liu;Lianshan Yan;Anlin Yi;Hengyun Jiang;Yan Pan;Lin Jiang;Xia Feng;Wei Pan;Bin Luo; Appeared in: IEEE Photonics Journal Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9 Publisher: IEEE
» Ultrahigh-Density 256-Channel Neural Sensing Microsystem Using TSV-Embedded Neural Probes
 Abstract:Highly integrated neural sensing microsystems are crucial to capture accurate signals for brain function investigations. In this paper, a 256-channel neural sensing microsystem with a sensing area of 5 × 5 mm 2 is presented based on 2.5-D through-silicon-via (TSV) integration. This microsystem composes of dissolvable μ-needles, TSV-embedded μ-probes, 256-channel neural amplifiers, 11-bit area-power-efficient successive approximation register analog-to-digital converters, and serializers. This microsystem can detect 256 electrocorticography and local field potential signals within a small area of 5 mm × 5 mm. The neural amplifier realizes 57.8 dB gain with only 9.8 μW per channel. The overall power of this microsystem is only 3.79 mW for 256-channel neural sensing. A smaller microsystem with dimension of 6 mm × 4 mm has been also implanted into rat brain for somatosensory evoked potentials (SSEPs) recording by using contralateral and ipsilateral electrical stimuli with intensity from 0.2 to 1.0 mA, and successfully observed different SSEPs from left somatosensory cortex of a rat. Autors: Yu-Chieh Huang;Po-Tsang Huang;Shang-Lin Wu;Yu-Chen Hu;Yan-Huei You;Jr-Ming Chen;Yan-Yu Huang;Hsiao-Chun Chang;Yen-Han Lin;Jeng-Ren Duann;Tzai-Wen Chiu;Wei Hwang;Kuan-Neng Chen;Ching-Te Chuang;Jin-Chern Chiou; Appeared in: IEEE Transactions on Biomedical Circuits and Systems Publication date: Oct 2017, volume: 11, issue:5, pages: 1013 - 1025 Publisher: IEEE

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