Electrical and Electronics Engineering publications abstract of: 01-2018 sorted by title, page: 14

» The 2017 Visualization Technical Achievement Award
Abstract:
The 2017 Visualization Technical Achievement Award goes to Jeffrey Heer in recognition of his work on the design, development, dissemination, and popularization of languages for visualization. The IEEE Visualization & Graphics Technical Committee (VGTC) is pleased to award Jeffrey Heer the 2017 Visualization Technical Achievement Award.
Autors: Jeffrey Heer;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: xxvii - xxviii
Publisher: IEEE
 
» The 24-Core POWER9 Processor With Adaptive Clocking, 25-Gb/s Accelerator Links, and 16-Gb/s PCIe Gen4
Abstract:
The POWER9TM family of chips is fabricated in 14-nm silicon-on-insulator finFET technology using 17 levels of copper interconnect. The 695-mm2 24-core microprocessor features a new core based on an execution slice microarchitecture. The chip contains 8 billion transistors and has 120 MB of eDRAM L3 cache. The processor features an adaptive clock strategy to reduce timing margin needed during power supply droop events by embedding analog voltage-droop monitors that direct a digital phase-locked loop to immediately reduce clock frequency in response to a droop event. The scale-out chip IO subsystem supports up to 300-GB/s accelerator bandwidth using new 25-Gb/s links, 48 lanes of PCIeGen4 totaling 192 GB/s, eight ports of 2667 MT/s DDR4, and 256 GB/s of symmetric multiprocessor (SMP) interconnect. The scale-up chip adds additional SMP bandwidth and replaces the DDR4 memory interface with eight ports of differential memory interfaces with 230 GB/s of bandwidth resulting in 12.9 Tb/s of total off-chip bandwidth.
Autors: Christopher Gonzalez;Michael Floyd;Eric Fluhr;Phillip Restle;Daniel Dreps;Michael Sperling;Rahul Rao;David Hogenmiller;Christos Vezyrtis;Pierce Chuang;Daniel Lewis;Ricardo Escobar;Vinod Ramadurai;Ryan Kruse;Juergen Pille;Ryan Nett;Pawel Owczarczyk;Jo
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jan 2018, volume: 53, issue:1, pages: 91 - 101
Publisher: IEEE
 
» The art of release notes [Resources at work]
Abstract:
Over the years, programmers have developed all sorts of conventions to wrangle the infinitely malleable nature of software. There are rules for how new versions should be numbered; how variables and functions should be named; the use of README files; and so on. Such measures provide consistency, especially for people grappling with software written by others, which can otherwise be a maddeningly obfuscated black box.
Autors: Amy Nordrum;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 21 - 21
Publisher: IEEE
 
» The Clarity of Hindsight: The First-Ever IMS Three Minute Thesis Competition [MTT Society News]
Abstract:
Presents MTTS society events, activities, and news.
Autors: John W. Bandler;Erin M. Kiley;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2018, volume: 19, issue:1, pages: 116 - 123
Publisher: IEEE
 
» The Complexity of Bit Retrieval
Abstract:
Bit retrieval is the problem of reconstructing a periodic binary sequence from its periodic autocorrelation, with applications in cryptography and x-ray crystallography. After defining the problem, with and without noise, we describe and compare various algorithms for solving it. A geometrical constraint satisfaction algorithm, relaxed-reflect-reflect, is currently the best algorithm for noisy bit retrieval.
Autors: Veit Elser;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2018, volume: 64, issue:1, pages: 412 - 428
Publisher: IEEE
 
» The curious incident of the robocar in the night-time
Abstract:
Actual self-driving cars-with no one behind the wheel-will enter commercial service in 2018. You may now exhale. Yes, it's true, but here's the caveat: The service will be severely circumscribed. At most, we’ll see robocars serving as taxis in certain well-mapped suburbs. At least, we’ll see passenger-free robocars that reposition themselves by night so that commuters can have access to them come morning. But that's still what experts call Level 4 autonomy. Here’s the hierarchy: At Level 5, a car can do it all. At Level 4, the car does it all only in certain areas, under certain conditions. At Level 3, drivers must be prepared to take control after a 10-second warning. At Level 2, they must pay attention all the time. Level 1 helps with the braking. Level 0 has power windows.
Autors: Philip E. Ross;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 44 - 45
Publisher: IEEE
 
» The Deep Regression Bayesian Network and Its Applications: Probabilistic Deep Learning for Computer Vision
Abstract:
Deep directed generative models have attracted much attention recently due to their generative modeling nature and powerful data representation ability. In this article, we review different structures of deep directed generative models and the learning and inference algorithms associated with the structures. We focus on a specific structure that consists of layers of Bayesian networks (BNs) due to the property of capturing inherent and rich dependencies among latent variables. The major difficulty of learning and inference with deep directed models with many latent variables is the intractable inference due to the dependencies among the latent variables and the exponential number of latent variable configurations. Current solutions use variational methods, often through an auxiliary network, to approximate the posterior probability inference. In contrast, inference can also be performed directly without using any auxiliary network to maximally preserve the dependencies among the latent variables. Specifically, by exploiting the sparse representation with the latent space, max-max instead of maxsum operation can be used to overcome the exponential number of latent configurations. Furthermore, the max-max operation and augmented coordinate ascent (AugCA) are applied to both supervised and unsupervised learning as well as to various inference. Quantitative evaluations on benchmark data sets of different models are given for both data representation and feature-learning tasks.
Autors: Siqi Nie;Meng Zheng;Qiang Ji;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2018, volume: 35, issue:1, pages: 101 - 111
Publisher: IEEE
 
» The Differential Factor [Editorial]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Cristian Quintero;
Appeared in: IEEE Potentials
Publication date: Jan 2018, volume: 37, issue:1, pages: 3 - 3
Publisher: IEEE
 
» The Effect of EV Aggregators With Time-Varying Delays on the Stability of a Load Frequency Control System
Abstract:
Participation of electric vehicles (EVs) aggregators in frequency regulation service may cause time-varying delays in load frequency control (LFC) systems. These time-varying delays affect the performance and even cause instability of power systems. In this paper, we investigate a single and multiple time-varying delays-dependent stability of an LFC system with participation of EV aggregators. Based on the Lyapunov theory and linear matrix inequality approach, we propose delay-dependent stability criteria for a single and multiple time-varying delays using the Wirtinger-based improved integral inequality. With the stability criteria, we obtain delay margins for LFC with a single and two EV aggregators and investigate the interaction among the delay margins, PI controller gains, and participation ratios of EV aggregators. In addition, we investigate the significance of time-varying delays in fast-response resources by comparing the delay margin obtained in EV aggregator model with that obtained in delayed conventional generators. We discuss an extension to multiarea LFC systems and guidelines on how to improve performance of LFC systems under time-varying delays. We expect that the proposed criteria can help to guide the determination of delay requirements for EV aggregators participating in frequency regulation service.
Autors: Kab Seok Ko;Dan Keun Sung;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 669 - 680
Publisher: IEEE
 
» The Effects of a Transverse Anisotropy Dielectric Rod in Excitation and Amplification Phenomena of Hybrid Electromagnetic Waves in a Cylindrical Metallic Waveguide
Abstract:
In this paper, a novel waveguide made of a hollow long metallic cylindrical column with a transverse anisotropy dielectric rod (TADR) is studied. The dispersion relation of hybrid electromagnetic waves is obtained in this structure, and its diagram variations will be investigated. The effects of dielectric permittivity coefficients of TADR on the dispersion relation of slow waves is studied. The mechanism of wave generation and its amplification phenomena by a thin annular relativistic electron beam are investigated for hybrid modes. Also, the graphs of operating frequency and the graphs of growth rate will be presented for the waves during the electron beam injection. The computations have done for terahertz hybrid waves.
Autors: Saeed Zahedi;Bahram Jazi;Zeinab Rahmani;Shima Kaabomeir;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2018, volume: 46, issue:1, pages: 72 - 83
Publisher: IEEE
 
» The Effects of Coding Schemes on Vibrotactile Biofeedback for Dynamic Balance Training in Parkinson’s Disease and Healthy Elderly Individuals
Abstract:
Coding scheme for earlier versions of vibrotactile biofeedback systems for balance-related applications was primarily binary in nature, either on or off at a given threshold (range of postural tilt), making it unable to convey information about error magnitude. The purpose of this paper was to explore the effects of two coding schemes (binary versus continuous) for vibrotactile biofeedback during dynamic weight-shifting exercises that are common physical therapists’ recommended balance exercises used in clinical settings. Nine individuals with idiopathic Parkinson’s disease and nine healthy elderly individuals participated in this paper. All participants performed dynamic weight-shifting exercises assisted with either the binary or continuous vibrotactile biofeedback delivered using with vibrating actuators (tactors) in either the anterior–posterior or medial–lateral direction. Participants’ limits of stability at pre and post exercises were compared to evaluate the effects of the exercises on their range of motion. The continuous coding scheme produced significantly better performance than the binary scheme when both groups were performing dynamic weight-shifting balance exercises with assistive vibrotactile biofeedback. The results have implications in terms of maximizing the effects of error-driven motor learning and increasing performance on balance rehabilitation training combined with vibrotactile biofeedback.
Autors: Beom-Chan Lee;Alberto Fung;Timothy A. Thrasher;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Jan 2018, volume: 26, issue:1, pages: 153 - 160
Publisher: IEEE
 
» The Effects of N2O Plasma Treatment on the Device Performance of Solution-Processed a-InMgZnO Thin-Film Transistors
Abstract:
In this paper, the effects of N2O plasma treatment (PT) at various temperatures on the performances of InMgZnO (IMZO) thin-film transistors (TFTs) were investigated. As a result, the TFTs with N2O plasma-treated (10 W) IMZO channel layers at 100° for 10 min showed five times higher linear field-effect mobility compared to the untreated IMZO. The N2O PT did not cause any significant changes to the crystal structure, surface roughness of the IMZO thin films. However, an X-ray photoelectron spectroscopy study confirmed that the oxygen-vacancy defect density of the channel layer decreases via the N2O PT with temperature increased, and the reduction of oxygen vacancies leads to a decrease of off-current (IOFF). It was found out that the refractivity of the channel layer increases with PT temperature increased, and the improvement of the film density makes the on-current (ION) higher, resulting in high mobility and high ratio. Our study suggests that moderate N2O PT temperature can be adopted to improve the device performances.
Autors: Jin Cheng;Zhinong Yu;Xuyang Li;Jian Guo;Wei Yan;Jianshe Xue;Wei Xue;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2018, volume: 65, issue:1, pages: 136 - 141
Publisher: IEEE
 
» The Explanatory Visualization Framework: An Active Learning Framework for Teaching Creative Computing Using Explanatory Visualizations
Abstract:
Visualizations are nowadays appearing in popular media and are used everyday in the workplace. This democratisation of visualization challenges educators to develop effective learning strategies, in order to train the next generation of creative visualization specialists. There is high demand for skilled individuals who can analyse a problem, consider alternative designs, develop new visualizations, and be creative and innovative. Our three-stage framework, leads the learner through a series of tasks, each designed to develop different skills necessary for coming up with creative, innovative, effective, and purposeful visualizations. For that, we get the learners to create an explanatory visualization of an algorithm of their choice. By making an algorithm choice, and by following an active-learning and project-based strategy, the learners take ownership of a particular visualization challenge. They become enthusiastic to develop good results and learn different creative skills on their learning journey.
Autors: Jonathan C. Roberts;Panagiotis D. Ritsos;James R. Jackson;Christopher Headleand;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 791 - 801
Publisher: IEEE
 
» The ezPixel lights it up [Resources]
Abstract:
I've been an EE and digital logic designer for over 30 years. For the past 25 years I've been using FPGAs almost exclusively for designs I create for a variety of professional applications. For the uninitiated, FPGAs are field-programmable gate arrays, which essentially means they are reconfigurable hardware chips. My work is enjoyable and satisfying, but recently I’ve wanted to explore fun projects that are quite different from the day job. I also wanted to bring my FPGA skills to the maker movement: FPGAs are rarely used there, largely because working with them is considered difficult compared with the relative simplicity of an Arduino.
Autors: Thomas Burke;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 18 - 19
Publisher: IEEE
 
» The Founder: W.H. Merrill and the Science of Safety [History]
Abstract:
Most people in the electrical industry are very familiar with the company known as Underwriters Laboratories (UL). Today, UL is a global corporation with 170 facilities, 4.5 million ft<sup>2</sup> of laboratory and office space, and 13,000 employees worldwide. The corporation oversees more than 1,500 safety and guidance documents and conducts nearly 100,000 product investigations per year. However, most people are not aware of UL's founder and how the history and origins of this organization are integrally connected with the birth of late 19th-century technology that helped create the world we know today.
Autors: David Dini;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jan 2018, volume: 24, issue:1, pages: 8 - 113
Publisher: IEEE
 
» The garage fab [Resources]
Abstract:
Electronics enthusiasts like being able to make things themselves. In IEEE Spectrum's Hands On column, we've detailed how readers can make their own solder reflow ovens, conductive ink, and synthetic aperture radars. But making DIY integrated circuits seemed impossibly out of reach. After all, building a modern fab is astronomically expensive: For example, in 2017 Intel announced it was investing US $7 billion to complete a facility for making chips with 7-nanometer- scale features. But Sam Zeloof was not deterred. This 17-year-old high school student has started making chips in his garage,albeit with technology that's a few steps back along the curve of Moore's Law. Zeloof says he has been working on his garage fab, located in his home near Flemington, N.J., for about a year. He began thinking about how to make chips as his "way of trying to learn what's going on inside semiconductors and transistors. I started reading old books and old patents because the newer books explain processes that require very expensive equipment."
Autors: Stephen Cass;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 17 - 18
Publisher: IEEE
 
» The Generalized Degrees of Freedom Region of the MIMO Z-Interference Channel With Delayed CSIT
Abstract:
The generalized degrees of freedom (GDoF) region of the multiple-input multiple-output (MIMO) Gaussian Z-interference channel with an arbitrary number of antennas at each node is established under the assumption of delayed channel state information at transmitters (CSIT). The GDoF region is parameterized by , which links the interference-to-noise ratio (INR) to the signal-to-noise ratio (SNR) via . A new outer bound for the GDoF region is established by maximizing a bound on the weighted sum-rate of the two users, which in turn is obtained by using a combination of genie-aided side-information and an extremal inequality. The maximum weighted sum-rate in the high SNR regime is shown to occur when the transmission covariance matrix of the interfering transmitter has full rank. An achievability scheme based on block-Markov encoding and backward decoding is developed which uses interference quantization and digital multicasting to take advantage of the channel statistics of the cross-link, and the scheme is separately shown to be GDoF-optimal in both the weak () and strong () interference regimes. This is the first complete characterization of the GDoF region of any interference network with delayed CSIT, as well as the first such GDoF characterization of a MIMO network with delayed CSIT and arbitrary number of antennas at each node. For all antenna tuples, the GDoF region is shown to be equal to or larger than the degrees of freedom (DoF) region over the entire range of , which leads to a V-shaped maximum sum-- DoF as a function of , with the minimum occurring at . The delayed CSIT GDoF region and the sum-DoF are compared with their counterparts under perfect CSIT, thereby characterizing all antenna tuples and ranges of for which delayed CSIT is sufficient to achieve the perfect CSIT GDoF region (or sum-DoF). It is also shown that treating interference as noise is not, in general, GDoF-optimal for the MIMO Z-IC, even in the weak interference regime.
Autors: Kaniska Mohanty;Mahesh K. Varanasi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2018, volume: 64, issue:1, pages: 531 - 546
Publisher: IEEE
 
» The Good, the Bad, and the Ugly: A Theoretical Framework for the Assessment of Continuous Colormaps
Abstract:
A myriad of design rules for what constitutes a “good” colormap can be found in the literature. Some common rules include order, uniformity, and high discriminative power. However, the meaning of many of these terms is often ambiguous or open to interpretation. At times, different authors may use the same term to describe different concepts or the same rule is described by varying nomenclature. These ambiguities stand in the way of collaborative work, the design of experiments to assess the characteristics of colormaps, and automated colormap generation. In this paper, we review current and historical guidelines for colormap design. We propose a specified taxonomy and provide unambiguous mathematical definitions for the most common design rules.
Autors: Roxana Bujack;Terece L. Turton;Francesca Samsel;Colin Ware;David H. Rogers;James Ahrens;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 923 - 933
Publisher: IEEE
 
» The Hologram in My Hand: How Effective is Interactive Exploration of 3D Visualizations in Immersive Tangible Augmented Reality?
Abstract:
We report on a controlled user study comparing three visualization environments for common 3D exploration. Our environments differ in how they exploit natural human perception and interaction capabilities. We compare an augmented-reality head-mounted display (Microsoft HoloLens), a handheld tablet, and a desktop setup. The novel head-mounted HoloLens display projects stereoscopic images of virtual content into a user's real world and allows for interaction in-situ at the spatial position of the 3D hologram. The tablet is able to interact with 3D content through touch, spatial positioning, and tangible markers, however, 3D content is still presented on a 2D surface. Our hypothesis is that visualization environments that match human perceptual and interaction capabilities better to the task at hand improve understanding of 3D visualizations. To better understand the space of display and interaction modalities in visualization environments, we first propose a classification based on three dimensions: perception, interaction, and the spatial and cognitive proximity of the two. Each technique in our study is located at a different position along these three dimensions. We asked 15 participants to perform four tasks, each task having different levels of difficulty for both spatial perception and degrees of freedom for interaction. Our results show that each of the tested environments is more effective for certain tasks, but that generally the desktop environment is still fastest and most precise in almost all cases.
Autors: Benjamin Bach;Ronell Sicat;Johanna Beyer;Maxime Cordeil;Hanspeter Pfister;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 457 - 467
Publisher: IEEE
 
» The Hope to Live Long and Prosper [Speakers' Corner]
Abstract:
Discusses the importance of attracting young members to the MTT Society and examines the significance of their experiences, education, and future prospects.
Autors: Alfy Riddle;Bryant Baker;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2018, volume: 19, issue:1, pages: 134 - 135
Publisher: IEEE
 
» The IECEx System: How It Impacts the North America Hazardous Locations Industry
Abstract:
The International Electrotechnical Commission (IEC) System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres (referred to as the IECEx System) comprises four separate schemes that provide international services to industries involved with explosive atmosphere (Ex) applications. These services include the certification of Ex equipment, service facilities, and personnel competencies along with the licensing of an IECEx mark. Since its inception in 1999 as an Ex equipment certification scheme, the IECEx system has doubled the number of participating countries and increased the number of approved certification bodies by an order of magnitude (with six from North America).
Autors: Paul T. Kelly;Thorsten Arnhold;Marty Cole;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jan 2018, volume: 24, issue:1, pages: 24 - 31
Publisher: IEEE
 
» The Influence of Load on Risk-Based Small-Disturbance Security Profile of a Power System
Abstract:
This paper establishes a generic severity function that can be used to produce power system security risk profiles. It is illustrated by analyzing the impacts of system load attributes on the small-disturbance rotor angle stability of a power system. The load attributes contributing to the oscillatory modes can be considered as inherent uncertain variables within power systems and include load power variations, load composition, and load model parameters. Uncertainty in the renewable power generation is also incorporated in the probabilistic modelling and risk assessment to demonstrate the flexibility of the approach. A novel approach is proposed to select the severity functions to logically represent small-disturbance security margin. The risk profile of a power system has been presented considering the probability density functions of power system critical modal damping and a selected set of severity functions. The analysis techniques developed are illustrated with a modified version of the 68-bus NETS-NYPS power system with a high amount of renewable power penetration. The relative importance of the load attributes and the impact of these attributes on stability boundaries have been identified at varying risk levels with respect to their contribution to small-disturbance stability.
Autors: Kazi N. Hasan;Robin Preece;Jovica V. Milanović;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 557 - 566
Publisher: IEEE
 
» The Interactive Visualization Gap in Initial Exploratory Data Analysis
Abstract:
Data scientists and other analytic professionals often use interactive visualization in the dissemination phase at the end of a workflow during which findings are communicated to a wider audience. Visualization scientists, however, hold that interactive representation of data can also be used during exploratory analysis itself. Since the use of interactive visualization is optional rather than mandatory, this leaves a “visualization gap” during initial exploratory analysis that is the onus of visualization researchers to fill. In this paper, we explore areas where visualization would be beneficial in applied research by conducting a design study using a novel variation on contextual inquiry conducted with professional data analysts. Based on these interviews and experiments, we propose a set of interactive initial exploratory visualization guidelines which we believe will promote adoption by this type of user.
Autors: Andrea Batch;Niklas Elmqvist;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 278 - 287
Publisher: IEEE
 
» The Manhattan Frame Model—Manhattan World Inference in the Space of Surface Normals
Abstract:
Objects and structures within man-made environments typically exhibit a high degree of organization in the form of orthogonal and parallel planes. Traditional approaches utilize these regularities via the restrictive, and rather local, Manhattan World (MW) assumption which posits that every plane is perpendicular to one of the axes of a single coordinate system. The aforementioned regularities are especially evident in the surface normal distribution of a scene where they manifest as orthogonally-coupled clusters. This motivates the introduction of the Manhattan-Frame (MF) model which captures the notion of an MW in the surface normals space, the unit sphere, and two probabilistic MF models over this space. First, for a single MF we propose novel real-time MAP inference algorithms, evaluate their performance and their use in drift-free rotation estimation. Second, to capture the complexity of real-world scenes at a global scale, we extend the MF model to a probabilistic mixture of Manhattan Frames (MMF). For MMF inference we propose a simple MAP inference algorithm and an adaptive Markov-Chain Monte-Carlo sampling algorithm with Metropolis-Hastings split/merge moves that let us infer the unknown number of mixture components. We demonstrate the versatility of the MMF model and inference algorithm across several scales of man-made environments.
Autors: Julian Straub;Oren Freifeld;Guy Rosman;John J. Leonard;John W. Fisher;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2018, volume: 40, issue:1, pages: 235 - 249
Publisher: IEEE
 
» The Netherlands' carbon dilemma: sequester or recycle? [News]
Abstract:
As soon as the new Dutch government took office in October, it announced an aggressive target—to reduce carbon emissions by 49 percent by 2030. This will ultimately require the Netherlands to sequester 20 million metric tons of carbon dioxide per year-equivalent to the annual emissions produced by 4.5 coal-fired power plants. Sequestering that much CO2 underground will be difficult, whether it's captured directly from the flues of power stations and steel mills or extracted from the air. Currently, the Netherlands sequesters less than 10,000 metric tons of CO2 annually.
Autors: Alexander Hellemans;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 7 - 9
Publisher: IEEE
 
» The Optimal Assignment of Orthogonal Polyphase Sequences in CDMA Systems
Abstract:
In this letter, ternary semi-bent functions and a complex Hadamard matrix are used to construct spreading sequences for code-division multiple-access systems. An efficient assignment of these sequences to a lattice of regular hexagonal cells, which are mutually orthogonal within each cell and the adjacent cells, is achieved and most notably the number of sequences per cell is maximum possible. The large sequence reuse distances, being , and low cross-correlation between non-orthogonal sequences (in non-adjacent cells) make these sequences appealing for practical applications.
Autors: Liupiao Zhang;Yujuan Sun;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 109 - 112
Publisher: IEEE
 
» The Potential of Phosphorene Nanoribbons as Channel Material for Ultrascaled Transistors
Abstract:
Transport properties of realistic phosphorene nanoribbons (PNRs) with edge defects are studied by using statistical atomistic quantum transport simulations. Regarding the impact of nanoribbon width downscaling and increasing of edge defect percentage, we show that PNRs exhibit qualitatively similar behavior of the ON- and OFF-state conductance, and of the ON–OFF conductance ratio as graphene nanoribbons (GNRs). However, we demonstrate that PNRs are superior to GNRs in terms of the absolute values of the conductance parameters, and that PNRs are much more immune to edge defects than their graphene counterparts. This paper identifies PNRs as a more promising channel material than GNRs for the extremely scaled postsilicon transistor technology.
Autors: Mirko Poljak;Tomislav Suligoj;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2018, volume: 65, issue:1, pages: 290 - 294
Publisher: IEEE
 
» The Role of Silicon Substrate on the Leakage Current Through GaN-on-Si Epitaxial Layers
Abstract:
We present an investigation of vertical leakage in GaN-on-Si epitaxial stack through electrical characterization and device simulations. Different structures of increasing complexity have been fabricated and analyzed in order to achieve a complete understanding of the main transport mechanisms. We have clarified the role of the Si substrate through comparison of identical structures built on p-type and n-type Si substrates. We show that in the case of p-Si substrates the leakage current is sustained by carrier generation in the Si depletion region. We also find that experiments on structures grown on n-doped silicon are consistent with considering electron injection from the substrate through the AlN/Si barrier as the main current limiting mechanism. Our insights are supported by device simulations that consistently reproduce the experimental capacitance–voltage and current–voltage characteristics as a function of temperature for all the considered structures.
Autors: Luca Sayadi;Giuseppe Iannaccone;Oliver Häberlen;Gianluca Fiori;Manuel Tomberger;Lauri O. Knuuttila;Gilberto Curatola;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2018, volume: 65, issue:1, pages: 51 - 58
Publisher: IEEE
 
» The Software Architect and DevOps
Abstract:
DevOps practices deal with such things as the velocity of releases, how fast incidents are handled, and the enforcement of organizationally specified security practices. All these are critical for success in today’s environment, and the architect is critical for success in adopting DevOps practices. This instalment of the Pragmatic Architect explains why.
Autors: Len Bass;
Appeared in: IEEE Software
Publication date: Jan 2018, volume: 35, issue:1, pages: 8 - 10
Publisher: IEEE
 
» The Time-Domain Compensation Theorem and Its Application to Pulsed EM Scattering of Multiport Receiving Antennas
Abstract:
The time-domain (TD) compensation theorem concerning a general -port antenna system is derived with the aid of the reciprocity theorem of the time-convolution type. The compensation theorem describes the impact of a change in the antenna load matrix on receiving-antenna-scattering properties. As such, the obtained results can serve as the basis for tailoring the pulsed echo of loaded scatterers or for understanding the limitations of Thévenin’s and Norton’s antenna equivalent circuits. Illustrative numerical examples concerning both linear and nonlinear antenna loads validate the TD compensation theorem.
Autors: Martin Štumpf;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2018, volume: 66, issue:1, pages: 226 - 232
Publisher: IEEE
 
» The Topology ToolKit
Abstract:
This system paper presents the Topology ToolKit (TTK), a software platform designed for the topological analysis of scalar data in scientific visualization. While topological data analysis has gained in popularity over the last two decades, it has not yet been widely adopted as a standard data analysis tool for end users or developers. TTK aims at addressing this problem by providing a unified, generic, efficient, and robust implementation of key algorithms for the topological analysis of scalar data, including: critical points, integral lines, persistence diagrams, persistence curves, merge trees, contour trees, Morse-Smale complexes, fiber surfaces, continuous scatterplots, Jacobi sets, Reeb spaces, and more. TTK is easily accessible to end users due to a tight integration with ParaView. It is also easily accessible to developers through a variety of bindings (Python, VTK/C++) for fast prototyping or through direct, dependency-free, C++, to ease integration into pre-existing complex systems. While developing TTK, we faced several algorithmic and software engineering challenges, which we document in this paper. In particular, we present an algorithm for the construction of a discrete gradient that complies to the critical points extracted in the piecewise-linear setting. This algorithm guarantees a combinatorial consistency across the topological abstractions supported by TTK, and importantly, a unified implementation of topological data simplification for multi-scale exploration and analysis. We also present a cached triangulation data structure, that supports time efficient and generic traversals, which self-adjusts its memory usage on demand for input simplicial meshes and which implicitly emulates a triangulation for regular grids with no memory overhead. Finally, we describe an original software architecture, which guarantees memory efficient and direct accesses to TTK features, while still allowing for researchers powerful and easy bindings and extensions. T- K is open source (BSD license) and its code. online documentation and video tutorials are available on TTK's website [108].
Autors: Julien Tierny;Guillaume Favelier;Joshua A. Levine;Charles Gueunet;Michael Michaux;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 832 - 842
Publisher: IEEE
 
» The Web as a Software Connector: Integration Resting on Linked Resources
Abstract:
The web, seen as a graph of linked resources shared between microservices, can serve as an integration style. It offers unique characteristics and possibilities regarding dataflow, control flow, and other qualities, compared to file transfer, shared databases, remote procedure calls, and asynchronous messaging. Carrying these insights in your toolbox will make you aware of all the options to consider next time you build loosely coupled integrated systems.
Autors: Cesare Pautasso;Olaf Zimmermann;
Appeared in: IEEE Software
Publication date: Jan 2018, volume: 35, issue:1, pages: 93 - 98
Publisher: IEEE
 
» The Wet-Antenna Effect—A Factor to be Considered in Future Communication Networks
Abstract:
An accurate design of the fading margin in wireless communication networks requires good modeling of the relationship between the rain rate and the attenuation. In this paper, we discuss the effect of the wet antenna (WA) on the fading margin. We claim that this effect is not negligible in commercial -band (i.e., 60–90 GHz) technologies, where the microwave links are relatively short and the sensitivity of the signal to attenuation induced by rain is significant. Consequently, we propose a method for estimating the WA-induced attenuation, so it can be incorporated in the current models. Different from previous studies, our proposed method can be implemented on received signal level measurements, which are standardly produced by commercial microwave links (CMLs) and a single rain gauge. We demonstrate our results using actual measurements taken by 73 GHz CMLs of about 1 km, provided by Ericsson.
Autors: Jonatan Ostrometzky;Roi Raich;Lei Bao;Jonas Hansryd;Hagit Messer;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2018, volume: 66, issue:1, pages: 315 - 322
Publisher: IEEE
 
» Theoretical Performance of Space-Time Adaptive Processing for Ship Detection by High-Frequency Surface Wave Radars
Abstract:
In this paper, we analyze the levels of performance of the (full or reduced versions of) space-time adaptive processing (STAP) algorithms applied to high-frequency surface wave radars (HFSWRs) for marine target detection to verify whether this family outperforms the usual moving target indication (MTI) algorithms. In fact, STAP algorithms have well-known drawbacks (e.g., large amount of secondary data). The propagation and backscattering of radar signals are included in the covariance matrix calculation. Since the propagation and backscattering have to be derived from physical features of the sea (e.g., sea Doppler) and the atmosphere, we also include the difference induced by the waveform (pulsed radar/chirp) in our study. Moreover, since the inverse covariance matrix is used in the target detection algorithms, matrix conditioning is also inspected for practical implementation reasons. We numerically detail the performance (signal noise clutter ratio and conditioning number of the STAP algorithms) with regards to the MTI performance for several configurations of radar and sea state. These results show that the improvements of signal noise clutter ratio are counterbalanced by a raise of the conditioning number, except in the case of eigencanceler approach. The sea-state parameters have few effects on the performance unlike to radar parameters.
Autors: Jean-Marc Le Caillec;Tomasz Górski;Guillaume Sicot;Adam Kawalec;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2018, volume: 43, issue:1, pages: 238 - 257
Publisher: IEEE
 
» Theory and Experiment for Wireless-Powered Sensor Networks: How to Keep Sensors Alive
Abstract:
In this paper, we investigate a multi-node multi-antenna wireless-powered sensor network (WPSN) comprised of one power beacon and multiple sensor nodes. We have implemented a real-life multi-node multi-antenna WPSN testbed that operates in real time. We propose a beam-splitting beamforming technique that enables a power beacon to split microwave energy beams toward multiple nodes for simultaneous charging. We experimentally demonstrate that the beam-splitting beamforming technique achieves the Pareto optimality. For perpetual operation of the sensor nodes, we adapt an energy neutral control algorithm that keeps a sensor node alive by balancing the harvested and consumed power. The joint beam-splitting and energy neutral control algorithm is designed by means of the Lyapunov optimization technique. In our experiments, the proposed algorithm has successfully kept all sensor nodes alive by optimally splitting energy beams toward multiple sensor nodes.
Autors: Kae Won Choi;Phisca Aditya Rosyady;Lorenz Ginting;Arif Abdul Aziz;Dedi Setiawan;Dong In Kim;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 430 - 444
Publisher: IEEE
 
» Theory of Double Ladder Lumped Circuits With Degenerate Band Edge
Abstract:
A conventional periodic LC ladder circuit forms a transmission line that has a regular band edge between a passband and a stopband. Here for the first time, we develop the theory of simple yet unconventional double ladder circuit that exhibits a special degeneracy condition referred to as a degenerate band edge (DBE). The degeneracy occurs when four independent eigenstates coalesce into a single eigenstate at the DBE frequency. In addition to possible practical applications, this circuit may provide insight into DBE behavior that is not clear in more complex systems. We show that double ladder resonators exhibit unusual behavior of the loaded quality factor near the DBE, leading to a stable resonance frequency against load variations. These two properties in the proposed circuit are superior to the analogous properties in single ladder circuits. Our proposed analysis leads to analytic expressions for all circuit quantities thus providing insight into the very complex behavior near degeneracy points in periodic circuits. Interestingly, here we show for the first time That a DBE is obtained with unit cells that are symmetric along the propagation direction. The proposed theory of double ladders presented here has potential applications in filters, couplers, oscillators, and pulse shaping networks.
Autors: Jeff T. Sloan;Mohamed A. K. Othman;Filippo Capolino;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2018, volume: 65, issue:1, pages: 3 - 13
Publisher: IEEE
 
» Theory of Terminated Nonlinear Transmission Lines
Abstract:
Properly terminating a transmission line, in order to transfer the maximum available power to the load, is an important issue. The problem, fully analyzed in linear lines, is still considered as a persisting problem in the area of nonlinear transmission lines (NLTLs). In this paper, an accurate analysis is presented which gives a closed-form formula for the matching efficiency of the NLTLs. Using this analysis, optimal resistive terminating load for the NLTLs was extracted. These results will considerably ease the design of all kinds of the NLTL-based systems, such as high-frequency oscillators and ultrashort pulse generators. This consistent analysis also gives the reflection coefficient for the waves reflecting from the NLTLs load. It is shown that the NLTLs are far different from linear transmission lines in the both cases of matching efficiency and reflection coefficient. The obtained analytical results are verified with experimental measurements and SPICE simulations. Excellent agreements are obtained. It is also shown that the results of the introduced analysis make it possible to design the NLTL-based systems without any trial-and-error efforts.
Autors: Mohammad Samizadeh Nikoo;Seyed Morad-Ali Hashemi;Forouhar Farzaneh;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2018, volume: 66, issue:1, pages: 91 - 99
Publisher: IEEE
 
» Thermal Stability of TiN/Ti/p+-Si0.3Ge0.7 Contact With Ultralow Contact Resistivity
Abstract:
In this letter, the contact properties and thermal stability of TiN/Ti/p+ -Si0.3Ge0.7 contacts are investigated. We demonstrate that the insertion of an ultra-thin Ti interlayer is necessary to reduce the contact resistivity () as compared with a standard TiN/p+-Si0.3Ge0.7 direct contact. However, the Ti interlayer has to be thin enough to avoid degradation of the contact morphology after 500 °C annealing. This letter reveals further that the Ti encroachment into grooved SiGe regions under the contact interface is responsible for the increase seen after this annealing.
Autors: Jian Zhang;Hao Yu;Lin-Lin Wang;Marc Schaekers;D. Mocuta;Naoto Horiguchi;Nadine Collaert;Kristin De Meyer;Yu-Long Jiang;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2018, volume: 39, issue:1, pages: 83 - 86
Publisher: IEEE
 
» This AI hunts poachers
Abstract:
Every year, poachers kill about 27,000 African elephants-an astounding 8 percent of the population. If current trends continue, these magnificent animals could be gone within a decade. The solution, of course, is to stop poachers before they strike, but how to do that has long confounded authorities. In protected areas like wildlife preserves, elephants and other endangered animals may roam far and wide, while rangers can patrol only a small area at any time. "It's a two-part problem," explains Milind Tambe, a computer scientist at the University of Southern California, in Los Angeles. "Can you predict where poaching will happen? And can you [target] your patrols so that they're unpredictable, so that the poachers don't know the rangers are coming?"
Autors: Jean Kumagai;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 54 - 57
Publisher: IEEE
 
» Three-Dimensional CAD Model Matching With Anisotropic Diffusion Maps
Abstract:
In modern manufacturing, retrieval and reuse of the pre-existed three-dimensional (3-D) computer-aided design (CAD) models would greatly save time and cost in the product development cycle. For the 3-D CAD model retrieval, one is confronted with the quality of searching in large databases with models in complex structure and high dimension. This paper proposes a new 3-D model matching approach that reduces the data dimension and matches the models effectively. It is based on diffusion maps which integrate the random walk and anisotropic kernel to extract intrinsic features of models with complex geometries. The high-dimensional data points in diffusion space are projected into low-dimensional space and the low-dimension embedding coordinates are extracted as features. They are then used with the Grovmov Hausdorff distance for model retrieval. These coordinates could capture multiscale spectral properties of the 3-D geometry and have shown good robustness to noise. In the experiments, the proposed algorithm has shown better performance compared to the celebrated eigenmap approach in the 3-D model retrieval from the aspects of precision and recall.
Autors: Xin Lin;Kunpeng Zhu;Qing-Guo Wang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Jan 2018, volume: 14, issue:1, pages: 265 - 274
Publisher: IEEE
 
» Three-Dimensional CMOS Differential Folded Hall Sensor With Bandgap Reference and Readout Circuit
Abstract:
This paper presents a 3-D differential folded Hall sensor (HS) fabricated using standard 0.18- CMOS technology; this HS includes 1-D folded lateral Hall sensor (FLHS) and 2-D folded vertical Hall sensor (FVHS). The proposed 3-D HS is laterally folded to reduce the effective conduction length and to decrease the offset voltage; a p+ guard ring is used to narrow the conducting channel and to improve magnetosensitivity. The magnetosensitivity is improved two-fold and the offset is eliminated using the differential topology. The proposed 1-D FLHS is sensitive to magnetic induction perpendicular to the chip plane BZ through the fast accumulation–slow release mechanism; the proposed 2-D FVHS is responsive to magnetic induction parallel to the chip plane, BX and BY, based on the interaction between the magnetoresistor (MR) and magnetotransistor, where MR is more dominant. Notably, the proposed 3-D HS operates with a small offset voltage of 0.26 mV and without magnetic hysteresis. For 2-D FVHS, at a voltage gain of 89.6 dB, the maximum sensor output is approximately 196.4 mV at the applied magnetic induction of 5 mT and the maximum supply–current–related sensitivity SRI is approximately 5 943 V/ at a current consumption of 6.25 mA for - or -channel. For 1-D FLHS, the maximum at a bias current of 6.25 mA for -channel. The magntosensitivity SRI of 1-D FLHS is approximately 2.35 times that of 2-D FVHS. The designed 1-D FLHS is a comparable to the performance of other publications. However, it experiences a high nonlinearity error in output Hall voltage at a low bias current. By contrast, the proposed 1-D FLHS has a linear performance in output Hall voltage at a high bias current.
Autors: Guo-Ming Sung;Leenendra Chowdary Gunnam;Hsin-Kwang Wang;Wen-Sheng Lin;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2018, volume: 18, issue:2, pages: 517 - 527
Publisher: IEEE
 
» Three-Dimensional VLC Positioning Based on Angle Difference of Arrival With Arbitrary Tilting Angle of Receiver
Abstract:
Existing indoor positioning methods for visible-light communication systems require large database, powerful signal processing units, additional sensors, such as gyroscopes, or the receiver placed toward a certain angle. These assumptions limit the applications of the indoor positioning systems in low-cost scenarios. In this paper, we propose a novel positioning framework based on the angle differences of arrival (ADOA) in 3-D coordinate systems, which can be used in receivers with image sensors or photodiodes. The proposed ADOA positioning does not require the receiver to be placed toward a certain angle and no additional sensor is required. Two positioning algorithms are proposed: one is based on the method of exhaustion (MEX), and the other is based on the least squares method (LSM). The MEX algorithm is analytically proved to be the optimal, while the LSM algorithm has much lower complexity. Both the upper and lower bounds are derived for the average discrepancy between the exact position and the estimated position. These performance bounds can facilitate the design of a light-emitting diode array. Experimental results show that the MEX algorithm can achieve an average error of 3.20 cm with a time cost of 0.36 s, and the LSM algorithm can achieve an average error of 14.66 cm with a time cost of 0.001 s.
Autors: Bingcheng Zhu;Julian Cheng;Yongjin Wang;Jun Yan;Jinyuan Wang;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2018, volume: 36, issue:1, pages: 8 - 22
Publisher: IEEE
 
» Three-Mask Elevated-Metal Metal-Oxide Thin-Film Transistor With Self-Aligned Definition of the Active Island
Abstract:
Bottom-gate thin-film transistors (TFTs) are currently fabricated using either a three-mask back-channel-etched (BCE) or, with an additional mask for the definition of an etch-stop (ES) layer, a four-mask technology. The former offers a lower cost of manufacturing and a higher resolution, while the latter provides better device characteristics in terms of both performance and reliability. Presently reported is a three-mask process for realizing an elevated-metal metal-oxide TFT employing self-aligned patterning of the active island, also inherently incorporating an ES layer. This technology offers a TFT that combines the same protection of the channel, and hence, the good characteristics of an ES TFT, with the lower cost, reduced parasitic overlap capacitance, and smaller device-footprint of a BCE TFT.
Autors: Jiapeng Li;Lei Lu;Zhihe Xia;Hoi Sing Kwok;Man Wong;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2018, volume: 39, issue:1, pages: 35 - 38
Publisher: IEEE
 
» Three-Wave Mixing as the Limit of Nonlinear Dynamics Theory for Nonlinear Transmission Line-Type Metamaterials
Abstract:
Using nonlinear dynamics (NLD) theory, a linear time periodic equivalent circuit of a sinusoidally pumped distributed transmission line-type metamaterial is proposed. For small pump power and sufficient number of unit cells, it is shown that three-wave mixing, coupled with phase matching, can be used to determine the frequencies of the autonomous components and their propagation behavior. The resulting signal and idler waves satisfy the well-known Manley–Rowe relation. However, unlike NLD theory and stability analysis, three-wave mixing can be inaccurate for relatively large input power levels and/or short transmission lines. In particular, the waveform profile and consequently radiation of the autonomous frequencies located inside the light cone cannot be described using three-wave mixing and NLD and/or stability analysis must be applied.
Autors: Sameh Y. Elnaggar;Gregory N. Milford;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2018, volume: 66, issue:1, pages: 481 - 486
Publisher: IEEE
 
» Throughput Optimization in WLAN/Cellular Integrated Network Using Partially Overlapped Channels
Abstract:
The wireless network that integrates a heterogeneous cellular network and a WLAN is referred to as a WLAN/cellular integrated network (WCIN). In a fourth generation WCIN, in order to achieve collision-avoidance between the LTE-A and IEEE 802.11 family, some interference-free mechanisms, such as carrier sense adaptive transmission and listen-before-talk, are proposed. However, the interference-free medium access mechanisms leave some unexploited partially overlapped 802.11ac channels, which result in a waste of spectrum. In this paper, we propose an interference-tolerant medium access method to optimize the WCIN throughput by utilizing those partially overlapped channels (POCs). First, we show the feasibility of enhancing WLAN throughput by utilizing 802.11ac POCs in a WCIN. Second, we mathematically model the partial overlap when an 802.11ac channel is partially overlapping with an LTE-A component carrier. Third, we propose an interference-tolerant medium access mechanism to optimize the WCIN throughput. The interference-tolerant one ensures that the interference to LTE-A users is tolerable in a given WCIN. Finally, we construct a hardware-in-the-loop testbed to evaluate and compare our proposed mechanism with three other state-of-the-art mechanisms. The experimental results show that our approach achieves at most 39% more throughput than one of the state-of-the-art collision-avoidance mechanisms regarding the entire WCIN.
Autors: Jiayue Li;Tracy Yingying Cheng;Xiaohua Jia;Lionel M. Ni;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 157 - 169
Publisher: IEEE
 
» Tight Lower and Upper Bounds on the Minimum Distance of LDPC Codes
Abstract:
In this letter, we obtain lower and upper bounds on the minimum distance of low-density parity-check (LDPC) codes. The bounds are derived by categorizing the non-zero code words of an LDPC code into two categories of elementary and non-elementary. The first category contains code words whose induced subgraph has only degree-2 check nodes. We propose an efficient search algorithm that can find the elementary code words of an LDPC code with weight less than a certain value , exhaustively. We also derive a lower bound on the weight of non-elementary code words. By performing the search with , we either obtain an elementary code word with the smallest weight , or establish the lower bound of on . For the upper bound, we modify our search algorithm to reach elementary codewords of larger weights at the cost of being non-exhaustive. Once such a codeword is found, its weight acts as an upper bound on . We examine a large number of regular and irregular LDPC codes, and demonstrate the efficiency and versatility of our technique in finding lower and upper bounds on, and in many cases the exact value of, . Finding , or establishing search-based - ower or upper bounds, for many of the examined codes are out of the reach of any existing algorithm.
Autors: Yoones Hashemi;Amir H. Banihashemi;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 33 - 36
Publisher: IEEE
 
» Tight Upper Bound Performance of Full-Duplex MIMO-BICM-IDD Systems in the Presence of Residual Self-Interference
Abstract:
In this paper, we derive a tight upper bound on the performance of a coded full-duplex multiple-input multiple-output (MIMO)-based bidirectional transceiver. Iterative detection and decoding (IDD) are proposed to suppress the residual self-interference (SI) remaining after applying different stages of SI cancellation. IDD comprises an adaptive minimum mean-squared error filter with log-likelihood ratio demapping, while the soft decoder by using soft-in soft-out decoding utilizes the maximum a posteriori algorithm. Furthermore, bit-interleaved coded modulation is considered in the presence of additive white Gaussian noise over MIMO frequency non-selective Rayleigh fading channels. Simulation results are presented to demonstrate the bit-error rate (BER) performance as a function of the signal-to-noise ratio showing a close match to the SI-free case for the proposed system. Furthermore, we validate our results by deriving a tight upper bound on the performance of the proposed system using rate-1/2 convolutional codes together with -ary quadrature amplitude modulation, which asymptotically exhibits a close agreement with the simulated BER performance. Moreover, extrinsic information transfer chart analysis is used to investigate the convergence behavior of the proposed IDD receiver and to determine the number of iterations required for this convergence.
Autors: Mohamad A. Ahmed;Charalampos C. Tsimenidis;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 520 - 532
Publisher: IEEE
 
» TILA-S: Timing-Driven Incremental Layer Assignment Avoiding Slew Violations
Abstract:
As very large scale integration technology scales to deep submicrometer and beyond, interconnect delay greatly limits the circuit performance. The traditional 2-D global routing and subsequent net by net assignment of available empty tracks on various layers lacks a global view for timing optimization. To overcome the limitation, this paper presents a timing driven incremental layer assignment tool, to reassign layers among routing segments of critical nets and noncritical nets. Lagrangian relaxation techniques are proposed to iteratively provide consistent layer/via assignments. Modeling via min-cost flow for layer shuffling avoids using integer programming and yet guarantees integer solutions via uni-modular property of the inherent model. In addition, multiprocessing of partitions of the whole chip provides runtime speed up. Furthermore, a slew targeted optimization is presented to reduce the number of violations incrementally through iteration-based Lagrangian relaxation, followed by a post greedy algorithm to fix local violations. Certain parameters introduced in the models provide tradeoff between timing optimization and via count. Experimental results in both ISPD 2008 and industry benchmark suites demonstrate the effectiveness of the proposed incremental algorithms.
Autors: Derong Liu;Bei Yu;Salim Chowdhury;David Z. Pan;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2018, volume: 37, issue:1, pages: 231 - 244
Publisher: IEEE
 
» Time–Frequency Analysis of Seismic Data Using a Three Parameters S Transform
Abstract:
The S transform (ST) is one of the most commonly used time–frequency (TF) analysis algorithms and is commonly used in assisting reservoir characterization and hydrocarbon detection. Unfortunately, the TF spectrum obtained by the ST has a low temporal resolution at low frequencies, which lowers its ability in thin beds and channels detection. In this letter, we propose a three parameters ST (TPST) to optimize the TF resolution flexibly. To demonstrate the validity and effectiveness of the TPST, we first apply it to a synthetic data and a synthetic seismic trace and then to a filed data. Synthetic data examples show that this TPST achieves an optimized TF resolution, compared with the standard ST and modified ST with two parameters. Field data experiments illustrate that the TPST is superior to the ST in highlighting the channel edges. The lateral continuity of the frequency slice produced by the TPST is more continuous than that of the ST.
Autors: Naihao Liu;Jinghuai Gao;Bo Zhang;Fangyu Li;Qian Wang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2018, volume: 15, issue:1, pages: 142 - 146
Publisher: IEEE
 
» Time-to-Digital Converter With Sample-and-Hold and Quantization Noise Scrambling Using Harmonics in Ring Oscillators
Abstract:
A high-resolution, high-bandwidth, and noise-scrambling, time-to-digital converter (TDC) is presented. Its architecture, which exploits harmonics in ring oscillators, provides a sample-and-hold mechanism in the form of relative phase. This storage mechanism is highly insensitive to noise and allows for oversampling between input events, therefore, can be designed for very high bandwidth. It can achieve lower quantization noise with fewer measurements than noise-shaping TDCs. This paper presents the architecture in detail, an in-depth analysis of noise sensitivity of the time storage mechanism, and the results from a prototype implemented in a 28-nm CMOS process.
Autors: Juan Pablo Caram;Jeff Galloway;J. Stevenson Kenney;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2018, volume: 65, issue:1, pages: 74 - 83
Publisher: IEEE
 
» Time-Variant Microwave Absorption by Dielectric Barrier Discharge Plasma in Atmospheric Pressure Helium
Abstract:
A numerical investigation is performed to analyze the transient microwave absorption characteristics of parallel-plate helium dielectric barrier discharge (DBD). Because the plasma has rapid temporal and spatial variation, a time-variant plasma fluid model is used to track the change of plasma variables over time. When an ac voltage of 4.7 kV and an ac frequency of 10 kHz are supplied to the DBD, the plasma operates as cold-collisional plasma under atmospheric pressure. The calculation of the plasma fluid model shows that predominant peaks in electron density and temperature appear twice in a period of , which suggests uniform glow discharge. These variables can be converted to plasma frequency and collision frequency, respectively. Then, the results are reflected in a complex wavenumber of the Maxwell equation to calculate the amount of wave absorption. When a microwave of 10 GHz is launched toward the DBD, the absorption behaves as a function of plasma variables with the maximum at every discharge with an interval of . The time-varying absorption shows good agreement with the existing experimental measurement. The absorption is also studied as a change of gas discharge parameter. The increase in applied voltage bolsters the amount of absorption up to 2 times.
Autors: Yuna Kim;Inkyun Jung;Il-Young Oh;Doo-Soo Kim;Jong-Gwan Yook;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2018, volume: 46, issue:1, pages: 57 - 63
Publisher: IEEE
 
» Tip Fiber-Optic Intermodal Interferometer for Refractive Index Sensing
Abstract:
We propose an all-fiber-optic multimode interferometer for measuring liquid refractive index. The interferometer was manufactured by using the arc splice technique between standard single-mode fiber and optical microfiber. A maximum refractive index sensitivity of 112 dB/RIU is experimentally demonstrated. In addition, thermal effects exhibit low phase modulation (12 pm/°C) with minimal intensity variations (− dB/°C); as a result, cross sensitivity around RIU/°C and RIU/°C is obtained for intensity and phase modulation. The stability analysis shows minimal wavelength and power variations, 0.01 nm and 0.27 dB respectively, for constant temperature and refractive index. Spatial frequency analysis was explored as an alternative method to measure liquid refractive index avoiding thermal effects.
Autors: Yanelis Lopez-Dieguez;Julian M. Estudillo-Ayala;Daniel Jauregui-Vazquez;Luis A. Herrera-Piad;Juan M. Sierra-Hernandez;Juan C. Hernandez-Garcia;Marco Bienchetti;Jose R. Reyes-Ayona;Roberto Rojas-Laguna;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:1, pages: 15 - 18
Publisher: IEEE
 
» TopoAngler: Interactive Topology-Based Extraction of Fishes
Abstract:
We present TopoAngler, a visualization framework that enables an interactive user-guided segmentation of fishes contained in a micro-CT scan. The inherent noise in the CT scan coupled with the often disconnected (and sometimes broken) skeletal structure of fishes makes an automatic segmentation of the volume impractical. To overcome this, our framework combines techniques from computational topology with an interactive visual interface, enabling the human-in-the-Ioop to effectively extract fishes from the volume. In the first step, the join tree of the input is used to create a hierarchical segmentation of the volume. Through the use of linked views, the visual interface then allows users to interactively explore this hierarchy, and gather parts of individual fishes into a coherent sub-volume, thus reconstructing entire fishes. Our framework was primarily developed for its application to CT scans of fishes, generated as part of the ScanAllFish project, through close collaboration with their lead scientist. However, we expect it to also be applicable in other biological applications where a single dataset contains multiple specimen; a common routine that is now widely followed in laboratories to increase throughput of expensive CT scanners.
Autors: Alexander Bock;Harish Doraiswamy;Adam Summers;Cláudio Silva;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 812 - 821
Publisher: IEEE
 
» Toward Optimal Distributed Node Scheduling in a Multihop Wireless Network Through Local Voting
Abstract:
In a multihop wireless network, it is crucial but challenging to schedule transmissions in an efficient and fair manner. In this paper, a novel distributed node scheduling algorithm, called Local Voting, is proposed. This algorithm tries to semi-equalize the load (defined as the ratio of the queue length over the number of allocated slots) through slot reallocation based on local information exchange. The algorithm stems from the finding that the shortest delivery time or delay is obtained when the load is semi-equalized throughout the network. In addition, we prove that, with Local Voting, the network system converges asymptotically toward the optimal scheduling. Moreover, through extensive simulations, the performance of Local Voting is further investigated in comparison with several representative scheduling algorithms from the literature. Simulation results show that the proposed algorithm achieves better performance than the other distributed algorithms in terms of average delay, maximum delay, and fairness. Despite being distributed, the performance of Local Voting is also found to be very close to a centralized algorithm that is deemed to have the optimal performance.
Autors: Dimitrios J. Vergados;Natalia Amelina;Yuming Jiang;Katina Kralevska;Oleg Granichin;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 400 - 414
Publisher: IEEE
 
» Toward Smart Building Design Automation: Extensible CAD Framework for Indoor Localization Systems Deployment
Abstract:
Over the last years, many smart buildings applications, such as indoor localization or safety systems, have been subject of intense research. Smart environments usually rely on several hardware nodes equipped with sensors, actuators, and communication functionalities. The high level of heterogeneity and the lack of standardization across technologies make design of such environments a very challenging task, as each installation has to be designed manually and performed ad-hoc for the specific building. On the other hand, many different systems show common characteristics, like the strict dependency with the building floor plan, also sharing similar requirements such as a nodes allocation that provides sensing coverage and nodes connectivity. This paper provides a computer-aided design application for the design of smart building systems based on the installation of hardware nodes across the indoor space. The tool provides a site-specific algorithm for cost-effective deployment of wireless localization systems, with the aim to maximize the localization accuracy. Experimental results from real-world environment show that the proposed site-specific model can improve the positioning accuracy of general models from the state-of-the-art. The tool, available open-source, is modular and extensible through plug-ins allowing to model building systems with different requirements.
Autors: Andrea Cirigliano;Roberto Cordone;Alessandro A. Nacci;Marco Domenico Santambrogio;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2018, volume: 37, issue:1, pages: 133 - 145
Publisher: IEEE
 
» Towards a Dependable True Random Number Generator With Self-Repair Capabilities
Abstract:
Many secure-critical systems rely on true random number generators that must guarantee their operational functionality during its intended life. To this end, these generators are subject to intensive online testing in order to discover any flaws in their operation. The dependability of the different blocks that compose the system is crucial to guarantee the security. In this paper, we provide some general guidelines for designers to create more dependable true random number generators. In addition, a case of study where the system dependability has been improved is presented.
Autors: Honorio Martin;Giorgio Di Natale;Luis Entrena;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2018, volume: 65, issue:1, pages: 247 - 256
Publisher: IEEE
 
» Towards a Systematic Combination of Dimension Reduction and Clustering in Visual Analytics
Abstract:
Dimension reduction algorithms and clustering algorithms are both frequently used techniques in visual analytics. Both families of algorithms assist analysts in performing related tasks regarding the similarity of observations and finding groups in datasets. Though initially used independently, recent works have incorporated algorithms from each family into the same visualization systems. However, these algorithmic combinations are often ad hoc or disconnected, working independently and in parallel rather than integrating some degree of interdependence. A number of design decisions must be addressed when employing dimension reduction and clustering algorithms concurrently in a visualization system, including the selection of each algorithm, the order in which they are processed, and how to present and interact with the resulting projection. This paper contributes an overview of combining dimension reduction and clustering into a visualization system, discussing the challenges inherent in developing a visualization system that makes use of both families of algorithms.
Autors: John Wenskovitch;Ian Crandell;Naren Ramakrishnan;Leanna House;Scotland Leman;Chris North;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 131 - 141
Publisher: IEEE
 
» Towards Quality Aware Information Integration in Distributed Sensing Systems
Abstract:
In this paper, we present GDA, a generalized decision aggregation framework that integrates information from distributed sensor nodes for decision making in a resource efficient manner. Different from traditional approaches, our proposed GDA framework is able to not only estimate the reliability of each sensor, but also take advantage of its confidence information, and thus achieves higher decision accuracy. Targeting generalized problem domains, our framework can naturally handle the scenarios where different sensor nodes observe different sets of events whose numbers of possible classes may also be different. GDA also makes no assumption about the availability level of ground truth label information, while being able to take advantage of any if present. For these reasons, our approach can be applied to a much broader spectrum of sensing scenarios. In this paper, we also propose two extensions of the GDA framework, i.e., incremental GDA (I-GDA) and parallel GDA (P-GDA) to deal with streaming and large-scale data. The advantages of our proposed methods are demonstrated through both theoretic analysis and extensive experiments.
Autors: Wenjun Jiang;Chenglin Miao;Lu Su;Qi Li;Shaohan Hu;Shiguang Wang;Jing Gao;Hengchang Liu;Tarek F. Abdelzaher;Jiawei Han;Xue Liu;Yan Gao;Lance Kaplan;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2018, volume: 29, issue:1, pages: 198 - 211
Publisher: IEEE
 
» Tracking and Locking System for Shooter With Sensory Noise Cancellation
Abstract:
In the present global scenario, the dimensions of warfare has changed to such an extent that the soldiers are exposed to multiple threats, the risk of collateral damage to soldiers are now even higher. Since the government wants the loss of life to be minimized, this paper is to ease the soldiers work nature in urban warfare and close combat especially. The system minimizes the risk of soldier life by tracking and following the intruder movement till the gun is triggered. The system is purely an attachable accessory to a primary assault rifle, that a soldier usually has the system mounted on the top of assault rifle, which is fixed on the rail of the gun and the course moment of the gun is synced with the real time response of sensor unit system attached to the helmet of the soldier and map the movement of soldiers head. The sensor unit noise plays an important role on the accuracy of the target locking and firing system. The proposed method has the Kalman filter estimation to remove the noise. The target missing rate has been calculated for various conventional schemes and compared with proposed system. The proposed method performs well on the parameter of success rate on target.
Autors: M. Mohamed Rabik;T. Muthuramalingam;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2018, volume: 18, issue:2, pages: 732 - 735
Publisher: IEEE
 
» Tracking the Damping Contribution of a Power System Component Under Ambient Conditions
Abstract:
This letter presents a method for tracking the damping contribution of a power system component in near real-time based upon oscillation energy dissipation. By transforming the energy flow into the frequency domain, the new derivation demonstrates a new theoretical basis and a wider applicability of using the energy-flow theory to analyze power system damping problems. The concept is demonstrated via a non-linear simulation and an actual-system data set.
Autors: Ruichao Xie;Daniel J. Trudnowski;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 1116 - 1117
Publisher: IEEE
 
» Traffic Light Recognition for Complex Scene With Fusion Detections
Abstract:
Traffic light recognition is one of the important tasks in the studies of intelligent transport system. In this paper, a robust traffic light recognition model based on vision information is introduced for on-vehicle camera applications. Our contribution mainly includes three aspects. First, in order to reduce computational redundancy, the aspect ratio, area, location, and context of traffic lights are utilized as prior information, which establishes a task model for traffic light recognition. Second, in order to improve the accuracy, we propose a series of improved methods based on an aggregate channel feature method, including modifying the channel feature for each types of traffic light and establishing a structure of fusion detectors. Third, we introduce a method of inter-frame information analysis, utilizing detection information of previous frame to modify original proposal regions, which makes the accuracy further improved. In the comparison of other traffic light detection algorithms, our model achieves competitive results on the complex scene VIVA data set. Furthermore, an analysis of small target luminous object detection tasks is given.
Autors: Xi Li;Huimin Ma;Xiang Wang;Xiaoqin Zhang;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2018, volume: 19, issue:1, pages: 199 - 208
Publisher: IEEE
 
» Transceiver Design for MIMO VLC Systems With Integer-Forcing Receivers
Abstract:
In this paper, we investigate the transceiver design for multiple-input multiple-output visible light communication (VLC) systems that employ the integer-forcing (IF) lattice decoding technique. To facilitate the joint design of the transmitter precoder, the integer matrix and the receiver equalizer, we first give a necessary and sufficient condition for the integer matrix to be invertible over 1-D lattice. Based on this condition, we then propose a new method for choosing the integer matrix which achieves better performance than the existing lattice reduction method. Moreover, taking into account two typical constraints in VLC, we optimize transmit and receive matrices using the conditional gradient method or the projected gradient method. Finally, the integer matrix and the transmit and receive matrices are jointly optimized in an iterative manner. Simulation results are provided to demonstrate the performance improvement achieved by the proposed framework.
Autors: Nuo Huang;Xiaodong Wang;Ming Chen;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jan 2018, volume: 36, issue:1, pages: 66 - 77
Publisher: IEEE
 
» Transformation Optics for Full-Wave Calculation of Microwave Applicators With Elements in Translation
Abstract:
The aim of this letter is to propose full-wave calculation of microwave (MW) applicators with elements in translation based on transformation optics. In the proposed 2-D model, the motion region is surrounded by two slabs with time-varying anisotropic homogenous media on the basis of transformation optics: one is to compress the electric field and the other is to stretch the electric field. Thus, the electric field of applicators with elements in translation can be equivalently calculated by full-wave analysis without any remeshing steps. It is helpful to model the heating process of food or biological package transportation on conveyor belts in industrial MW heating accurately and efficiently.
Autors: Yinhong Liao;Wei Xiao;Zhiyan Wu;Haijing Zhou;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2018, volume: 28, issue:1, pages: 4 - 6
Publisher: IEEE
 
» Transient Evolution of Argon Radio Frequency Atmospheric Pressure Discharge After the Very First Breakdown
Abstract:
The very first breakdown in argon radio frequency (RF) atmospheric pressure discharge was realized by pulse modulation with a sufficiently long off-time. The afterward nonsteady temporal stage was monitored with voltage/current probes and a fast camera. Experimental results show that conventionally observed uniform RF atmospheric pressure discharge glows at steady phrase stem from the initial local weak glow through the intermediate stages of filamentation, splitting, branching, expansion, decay, and homogenization. Such a process should also possibly occur after the breakdown of a continuous wave RF atmospheric pressure discharge. During the filamentary stage of the discharge, unusual parallel branching is originated from centers of axial main filaments driven with symmetrical parallel electrodes. Physical mechanisms underlying the transient process are discussed.
Autors: Weigang Huo;Zhenfeng Ding;Yujun Ke;Licheng Tian;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2018, volume: 46, issue:1, pages: 8 - 13
Publisher: IEEE
 
» Transmission Filters Utilizing Cavity Resonances in Bandgap-Engineered Monomaterials
Abstract:
A monomaterial-based resonator structure is proposed here, which can replace the multilayer-based narrowband transmission filter. This new concept of introducing the effect of multilayered structures of different materials into a single material is based on etching out repeatable structures of two different dimensions on the same material. As the etched-out repeatable structures are of different dimensions, it is possible to obtain periodic layers of two different-effective refractive indices. This type of monomaterial-based optical filters avoids the challenges generally faced while fabricating multilayer structures of different heterogeneous materials having different refractive indices. The dependence of the filter action on the number of bilayers of two different-effective refractive-index materials formed by etching and on the cavity region thicknesses is studied. Although the study is done mainly on lithium niobate on insulator, but it is seen that similar effects occur for materials of varying refractive indices.
Autors: Rajorshi Bandyopadhyay;Rajib Chakraborty;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:2, pages: 189 - 192
Publisher: IEEE
 
» Transmit Optimization for Symbol-Level Spoofing
Abstract:
With recent developments in wireless communication technologies, malicious users can use them to commit crimes or launch terror attacks, thus imposing new threats on public security. To quickly respond to these attacks, authorized parities need to intervene in the malicious communication links over the air. This paper investigates the emerging wireless communication intervention problem at the physical layer. Unlike prior studies using jamming to disrupt or disable the targeted wireless communications, we propose a new physical-layer spoofing approach to change their communicated information. Consider an abstract three-node model over additive white Gaussian noise channels, in which a legitimate spoofer aims to spoof a malicious communication link from a malicious transmitter to a malicious receiver, such that the received message at the receiver is changed from the transmitter’s originally sent message to the one desired by the spoofer. We propose a new symbol-level spoofing scheme, where the spoofer designs the spoofing signal by exploiting the symbol-level relationship between each original constellation point of the transmitter and the desirable one of the spoofer. In particular, the spoofer aims to minimize the average spoofing-symbol-error-rate (SSER), which is defined as the average probability that the symbols decoded by the malicious receiver fail to be changed or spoofed, by designing its spoofing signals over symbols subject to the average transmit power constraint. By considering two cases when the malicious transmitter employs the widely-used binary phase-shift keying and quadrature phase-shift keying modulations, we obtain the respective optimal solutions to the two average SSER minimization problems. Numerical results show that the symbol-level spoofing scheme with optimized transmission achieves a much lower average SSER, as compared with other benchmark schemes.
Autors: Jie Xu;Lingjie Duan;Rui Zhang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2018, volume: 17, issue:1, pages: 41 - 55
Publisher: IEEE
 
» Transparent Ru–Si–O/In–Ga–Zn–O MESFETs on Flexible Polymer Substrates
Abstract:
With the development of novel device applications, e.g., in the field of Internet of Things or point-of-care personalized diagnostic systems, came an increased demand for MESFETs for fast and low-power consumption integrated circuits and active-matrix displays. In this paper, we present fabrication and characterization of transparent Ru–Si–O/In–Ga–Zn–O MESFETs on flexible substrates. The use of transparent conducting oxide, namely, Ru–Si–O, as Schottky gate electrode, allows for processing the devices at room temperature, enabling the utilization of such low-temperature substrates as polyethylene terephthalate foil and paper. It was shown that tuning the device geometry allows realization of transistors providing on-current up to 2 mA, while the highest on-to-off current ratio equals , with off-current below 1 nA, carrier mobility in the channel exceeds 9 cm, and subthreshold swing is below 250 mVdecade.
Autors: Jakub Kaczmarski;Andrzej Taube;Michał A. Borysiewicz;Marcin Myśliwiec;Krzysztof Piskorski;Krystyna Stiller;Eliana Kamińska;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2018, volume: 65, issue:1, pages: 129 - 135
Publisher: IEEE
 
» TreePOD: Sensitivity-Aware Selection of Pareto-Optimal Decision Trees
Abstract:
Balancing accuracy gains with other objectives such as interpretability is a key challenge when building decision trees. However, this process is difficult to automate because it involves know-how about the domain as well as the purpose of the model. This paper presents TreePOD, a new approach for sensitivity-aware model selection along trade-offs. TreePOD is based on exploring a large set of candidate trees generated by sampling the parameters of tree construction algorithms. Based on this set, visualizations of quantitative and qualitative tree aspects provide a comprehensive overview of possible tree characteristics. Along trade-offs between two objectives, TreePOD provides efficient selection guidance by focusing on Pareto-optimal tree candidates. TreePOD also conveys the sensitivities of tree characteristics on variations of selected parameters by extending the tree generation process with a full-factorial sampling. We demonstrate how TreePOD supports a variety of tasks involved in decision tree selection and describe its integration in a holistic workflow for building and selecting decision trees. For evaluation, we illustrate a case study for predicting critical power grid states, and we report qualitative feedback from domain experts in the energy sector. This feedback suggests that TreePOD enables users with and without statistical background a confident and efficient identification of suitable decision trees.
Autors: Thomas Mühlbacher;Lorenz Linhardt;Torsten Möller;Harald Piringer;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 174 - 183
Publisher: IEEE
 
» Trends in Agile Updated: Perspectives from the Practitioners
Abstract:
The Agile Conference is the largest global conference on agile software development, catering particularly to practitioners. This article reports on three keynotes at Agile 2017 and the second year of an IEEE Software conference initiative.
Autors: Rafael Prikladnicki;Casper Lassenius;Jeffrey C. Carver;
Appeared in: IEEE Software
Publication date: Jan 2018, volume: 35, issue:1, pages: 109 - 111
Publisher: IEEE
 
» Triggered Communication in Distributed Adaptive High-Gain EKF
Abstract:
This paper deals with the design of a distributed adaptive high-gain extended Kalman filtering (AHGEKF) approach based on triggering communication for nonlinear systems being composed of several interconnected subsystems. For each subsystem, a local AHGEKF is designed, which receives local measurements, communicates with other filters, and computes local state estimates. In order to reduce the information transmission frequency among the distributed estimators, a communication trigger is designed for each filter. Each filter transmits its current state estimate when its corresponding triggering criterion is satisfied. Sufficient conditions are provided under which the convergence and ultimate boundedness of the estimation error is guaranteed. A simulated chemical process is used to demonstrate the applicability and performance of the proposed approach.
Autors: Mohammad Rashedi;Jinfeng Liu;Biao Huang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Jan 2018, volume: 14, issue:1, pages: 58 - 68
Publisher: IEEE
 
» Triple Collocation to Assess Classification Accuracy Without a Ground Truth in Case of Earthquake Damage Assessment
Abstract:
The assessment of satellite image classifications is usually carried out using a test sample assumed as the ground truth, from which a confusion matrix is derived. There are cases where the reference data, even those coming from a ground survey, are affected by errors and do not represent a reliable truth. In the field of geophysical parameter retrieval, the triple collocation (TC) technique is applied for validating remotely sensed products when the source of test data (e.g., ground data) does not represent a reliable reference. TC is able to retrieve the error variances of three systems observing the same target parameter, assuming that their errors are independent. In this paper, we exploit the same idea to test the classification accuracy in cases where the ground truth is not available. We extend the TC approach to the classification problem for a general number of classes, but we solve it numerically for a two-class problem (i.e., collapsed and noncollapsed buildings). The specific case refers to the detection of L’Aquila 2009 earthquake damage from very high-resolution optical data. The image classification, performed by exploiting an object-based analysis, is compared with those from two different ground surveys carried out after the earthquake by different teams and with different purposes. This paper demonstrates the power of the TC approach for assessing the classification accuracy with no reliable ground truth available, and provides an insight into the problem of assessing damage, from satellite and on ground, in a very critical and unsafe situation, like the one occurring after an earthquake. Moreover, it was found that the remotely sensed product can have an order of accuracy comparable to that of at least one of the ground surveys.
Autors: Nazzareno Pierdicca;Roberta Anniballe;Fabrizio Noto;Christian Bignami;Marco Chini;Antonio Martinelli;Antonio Mannella;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jan 2018, volume: 56, issue:1, pages: 485 - 496
Publisher: IEEE
 
» TSCA: A Temporal-Spatial Real-Time Charging Scheduling Algorithm for On-Demand Architecture in Wireless Rechargeable Sensor Networks
Abstract:
The collaborative charging issue in Wireless Rechargeable Sensor Networks (WRSNs) is a popular research problem. With the help of wireless power transfer technology, electrical energy can be transferred from wireless charging vehicles (WCVs) to sensors, providing a new paradigm to prolong network lifetime. Existing techniques on collaborative charging usually take the periodical and deterministic approach, but neglect influences of non-deterministic factors such as topological changes and node failures, making them unsuitable for large-scale WRSNs. In this paper, we develop a temporal-spatial charging scheduling algorithm, namely TSCA, for the on-demand charging architecture. We aim to minimize the number of dead nodes while maximizing energy efficiency to prolong network lifetime. First, after gathering charging requests, a WCV will compute a feasible movement solution. A basic path planning algorithm is then introduced to adjust the charging order for better efficiency. Furthermore, optimizations are made in a global level. Then, a node deletion algorithm is developed to remove low efficient charging nodes. Lastly, a node insertion algorithm is executed to avoid the death of abandoned nodes. Extensive simulations show that, compared with state-of-the-art charging scheduling algorithms, our scheme can achieve promising performance in charging throughput, charging efficiency, and other performance metrics.
Autors: Chi Lin;Jingzhe Zhou;Chunyang Guo;Houbing Song;Guowei Wu;Mohammad S. Obaidat;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jan 2018, volume: 17, issue:1, pages: 211 - 224
Publisher: IEEE
 
» Tumor Cell Load and Heterogeneity Estimation From Diffusion-Weighted MRI Calibrated With Histological Data: an Example From Lung Cancer
Abstract:
Diffusion-weighted magnetic resonance imaging (DWI) is a key non-invasive imaging technique for cancer diagnosis and tumor treatment assessment, reflecting Brownian movement of water molecules in tissues. Since densely packed cells restrict molecule mobility, tumor tissues produce usually higher signal (a.k.a. less attenuated signal) on isotropic maps compared with normal tissues. However, no general quantitative relation between DWI data and the cell density has been established. In order to link low-resolution clinical cross-sectional data with high-resolution histological information, we developed an image processing and analysis chain, which was used to study the correlation between the diffusion coefficient (D value) estimated from DWI and tumor cellularity from serial histological slides of a resected non-small cell lung cancer tumor. Color deconvolution followed by cell nuclei segmentation was performed on digitized histological images to determine local and cell-type specific 2d (two-dimensional) densities. From these, the 3d cell density was inferred by a model-based sampling technique, which is necessary for the calculation of local and global 3d tumor cell count. Next, DWI sequence information was overlaid with high-resolution CT data and the resected histology using prominent anatomical hallmarks for co-registration of histology tissue blocks and non-invasive imaging modalities’ data. The integration of cell numbers information and DWI data derived from different tumor areas revealed a clear negative correlation between cell density and D value. Importantly, spatial tumor cell density can be calculated based on DWI data. In summary, our results demonstrate that tumor cell count and heterogeneity can be predicted from DWI data, which may open new opportunities for personalized diagnosis and therapy optimization.
Autors: Yi Yin;Oliver Sedlaczek;Benedikt Müller;Arne Warth;Margarita González-Vallinas;Bernd Lahrmann;Niels Grabe;Hans-Ulrich Kauczor;Kai Breuhahn;Irene E. Vignon-Clementel;Dirk Drasdo;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2018, volume: 37, issue:1, pages: 35 - 46
Publisher: IEEE
 
» Tunable Constant-Bandwidth Substrate-Integrated Bandstop Filters
Abstract:
A new method for designing tunable bandstop filters with constant fractional and absolute bandwidths (ABWs) is presented. The constant bandwidth is achieved through a new coupling structure, which is passive and consists only of coupling elements and transmission lines. Its theory of operation is presented, and design principles and tradeoffs are examined in detail. Several prototype filters are fabricated and measured to demonstrate the performance and versatility of this method. An octave-tunable filter with less than 12% fractional bandwidth variation is demonstrated, along with an octave-tunable filter with 12.3% variation in ABW variation, a filter with a 50% tuning range and less than 4% variation in ABW, and a four-pole octave-tunable filter with less than 4% variation in its 10-dB ABW. These results represent state-of-the-art performance when compared to other constant-bandwidth bandstop filters at frequencies higher than those compatible with lumped-element filters.
Autors: Mark D. Hickle;Dimitrios Peroulis;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2018, volume: 66, issue:1, pages: 157 - 169
Publisher: IEEE
 
» Tunable Low-Frequency Noise in Dual-Gate MoS2 Transistors
Abstract:
We have systematically studied the effect of the back-gate voltage on the low-frequency noise properties of the MoS2 transistors from 300 to 20 K in this work. The results show that the performance of the top-gate MoS2 transistor can be effectively tuned by the back-gate voltage . When increases to 20 V, the maximum on-current increases up to 588 / for the 1- channel length device, as well as five times reduction of the low-frequency noise and two times reduction in contact resistance. The Fermi-level modulation by adjusting turns out to be an effective way of improving contact resistance and low-frequency noise for future high-quality MoS2 metal-oxide–semiconductor field-effect transistors.
Autors: Xuefei Li;Tiaoyang Li;Zhenfeng Zhang;Xiong Xiong;Sichao Li;Yanqing Wu;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2018, volume: 39, issue:1, pages: 131 - 134
Publisher: IEEE
 
» Tunable Mid-Infrared Nanoscale Graphene-Based Refractive Index Sensor
Abstract:
A nanoscale refractive index sensor comprising of input–output graphene parallel plane waveguides coupled through a resonator is proposed. Operating as a wavelength selective structure in mid-infrared region, the sensor performance is based on the variation of the resonance wavelength of the structure. The simulation results obtained by numerical method of the finite difference time domain reveal linear dependency between the resonance wavelengths and the refractive indices of the material injected into the coupling resonator of the sensor, predictable by the resonance criterion of the resonator. The wavelength resolution of the detection system determines the overall sensor resolution. To utilize voltage dependency of graphene chemical potential, the wavelength range of the performance of the sensor can be tuned appropriately. The proposed sensor can be used as a platform for design of the sensors utilizing in various chemical and biomedical systems.
Autors: Alireza Dolatabady;Somayyeh Asgari;Nosrat Granpayeh;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2018, volume: 18, issue:2, pages: 569 - 574
Publisher: IEEE
 
» Tunable Orbital Angular Momentum Generation Using All-Fiber Fused Coupler
Abstract:
We propose an effective approach to generate tunable orbital angular momentum (OAM) beam based on all-fiber fused coupler consisting of a single mode fiber (SMF) and a two-mode fiber. The fundamental mode in the SMF is directly coupled to the LP11 mode group (TE0,1, , TM0,1) by appropriately phase matching the modes in the fiber coupler. The experimental results demonstrate that the OAM beam is produced by combining and TE0,1 (or and TM0,1) with a /2 phase shift and the OAM topological charge could be tuned from to by adjusting a polarizer set at the output end of fiber.
Autors: Shuzhi Yao;Guobin Ren;Ya Shen;Youchao Jiang;Bofeng Zhu;Shuisheng Jian;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:1, pages: 99 - 102
Publisher: IEEE
 
» Two-Wave Cherenkov Oscillator With Moderately Oversized Slow-Wave Structure
Abstract:
This paper describes a new design of a relativistic Cherenkov oscillator with strong modulation of the e-beam current at the input of two-sectioned slow-wave structure, as well as numerical and experimental results on generation of few gigawatt-level -band pulses with pulse duration of up to 35 ns. Due to special phase shift between two sections and electrodynamic coupling between surface wave and volume mode, the first one is locked at the upper boundary of the passband and the second one gains more transparency. An electron beam can interact simultaneously with two waves with higher power conversion efficiencies, which in simulations amount up to 47% and 30% for high (~4 T) and low (~1 T) guiding magnetic fields, correspondingly. The tests of the geometry optimized in simulations were performed on the base of SINUS-7 high-current electron accelerator in the diode voltage range of 400–850 kV and current from 7 to 16 kA. The repeated and full-pulsewidth generation of about 1.5-GW microwave power is achieved only in the low magnetic field. The pulse shortening and the mode competition took place in the strong magnetic field. The results are considered as preliminary for creation of the efficient relativistic millimeter-wave oscillators at magnetic fields below the cyclotron resonance.
Autors: Vladislav V. Rostov;Alexander V. Gunin;Ruslan V. Tsygankov;Ilya V. Romanchenko;Michael I. Yalandin;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2018, volume: 46, issue:1, pages: 33 - 42
Publisher: IEEE
 
» Two-Way Relay Selection for Millimeter Wave Networks
Abstract:
In this letter, we investigate the potential benefits of deploying two-way amplify-and-forward relays to help bidirectional data exchange between two end users in a millimeter wave network. While the locations of the two end users are fixed, the locations of the potential relays are modeled as a homogeneous Poisson point process. A relay is thus selected to maximize the minimum of the two users’ end-to-end signal-to-noise ratios. For this system, we derive the coverage probability and show that the considered relay selection significantly outperforms the random selection scheme in terms of coverage and spectral efficiency.
Autors: Khagendra Belbase;Chintha Tellambura;Hai Jiang;
Appeared in: IEEE Communications Letters
Publication date: Jan 2018, volume: 22, issue:1, pages: 201 - 204
Publisher: IEEE
 
» Two-Wire Bus Combining Full Duplex Body-Sensor Network and Multilead Biopotential Measurements
Abstract:
Classical approaches to make high-quality measurements of biopotential signals require the use of shielded or multiwire cables connecting the electrodes to a central unit in a star arrangement. As a consequence, increasing the number of leads increases cabling and connector complexity, which is not only limiting the patient comfort but is also anticipated as the main limiting factor to future miniaturization and cost reduction of tomorrow's wearables. We have recently introduced a novel sensing architecture that significantly reduces the cabling complexity by eliminating shielded or multiwire cables and by allowing simple connectors, thanks to a bus arrangement. In this architecture, electrodes are replaced by so-called cooperative sensors that require synchronous operation for systems larger than two sensors. This paper presents a novel full duplex body-sensor network based on a simple two-wire bus that combines biopotential measurements, synchronization, and gathering of data in a single cooperative sensor with a throughput up to 2 Mb/s. When compared to others, the suggested approach is advantageous as it keeps the cabling complexity at its minimum and does not require every sensor to be equipped with wireless communication capabilities. First experimental measurements demonstrated the reliability of the approach for a wearable 12-lead electrocardiogram monitoring system tested in real-life scenario.
Autors: Michaël Rapin;Josias Wacker;Olivier Chételat;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2018, volume: 65, issue:1, pages: 113 - 122
Publisher: IEEE
 
» U.S. supercomputing strikes back
Abstract:
In November of 2012, the semiannual Top500 rankings of the world's supercomputers gave top billing to a machine constructed at the Oak Ridge National Laboratory, in Tennessee. Aptly named Titan, the machine boasted a peak performance of more than 27 x 1015 floating-point operations per second, or 27 petaflops. It was an immense computing resource for researchers in government, industry, and academe, and being at the top of the supercomputing heap, it helped to boost pride within the U.S. high‑performance computing community.
Autors: David Schneider;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 52 - 53
Publisher: IEEE
 
» Ultra-Low-Jitter Fully Tunable Baseband Pulse Generator for UWB Applications
Abstract:
A fully tunable baseband ultra-wideband pulse generator realized with commercial off-the-shelf components is presented. It is made of high-speed logic gates and comparators, and it is compliant with the current-mode logic digital standard. The pulse emitted power and bandwidth are tunable with pulsewidth and amplitude variation, which shows high flexibility. This advantage simplifies the design of the downstream shaping network, as so to be compliant with international regulations. A differential output with very low jitter is demonstrated.
Autors: Marco Garbati;Etienne Perret;Romain Siragusa;Christophe Halopé;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2018, volume: 66, issue:1, pages: 420 - 430
Publisher: IEEE
 
» Ultra-Wideband Lossless Cavity-Backed Vivaldi Antenna
Abstract:
An ultra-wideband, lossless cavity-backed Vivaldi antenna array for flush-mounting applications is proposed. Eigenmode analysis, used to investigate antenna-cavity interaction, has shown that the entire structure may resonate within the band of interest resulting in a significant degradation of antenna performance. A simple approach based on connecting the array’s edge elements in E-plane to the cavity walls is utilized to eliminate the deleterious impact of these cavity resonances. The proposed antenna is a array with three elements in E-plane and four elements in H-plane, fabricated using stacked all-metal printed circuit board technique. Resonant-free behavior with gain better than 5 dBi and VSWR <2 from 1.5 to 7.5 GHz is obtained. High-quality radiation patterns with sidelobe levels lower than 20 dB over the same bandwidth are also demonstrated. Scan performance of the proposed cavity-backed antenna is investigated in two principal planes and is shown to have similar performance compared to its free-standing counterpart.
Autors: Elie G. Tianang;Mohamed A. Elmansouri;Dejan S. Filipovic;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2018, volume: 66, issue:1, pages: 115 - 124
Publisher: IEEE
 
» Ultrafast Measurements and Physical Modeling of NBTI Stress and Recovery in RMG FinFETs Under Diverse DC–AC Experimental Conditions
Abstract:
Threshold voltage shift () due to negative-bias temperature instability (NBTI) in p-FinFETs with replacement metal gate-based high-k metal gate process is measured using an ultrafast method. A comprehensive modeling framework involving uncorrelated contributions from the generation of interface traps (), hole trapping in preexisting (), and generation of new () bulk insulator traps is used to quantify measured data. The model can explain dc stress and recovery data over an extended temperature range (−40 °C to 150 °C), for different stress and recovery biases. It can explain ac stress and recovery data for different bias, temperature, frequency, and duty cycle. The differences in time kinetics and temperature activation of , , and , and their relative dominance at various experimental conditions are shown. End-of-life NBTI for dc and ac stress is estimated by using the model and compared to prediction from conventional analytical methods.
Autors: Narendra Parihar;Uma Sharma;Richard G. Southwick;Miaomiao Wang;James H. Stathis;Souvik Mahapatra;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2018, volume: 65, issue:1, pages: 23 - 30
Publisher: IEEE
 
» Ultrahigh Sensitivity Plasmonic Refractive-Index Sensor for Aqueous Environment
Abstract:
We propose a short-length ultra-high sensitivity plasmonic-integrated optic-refractive-index sensor for aqueous medium. The sensor is based on hybrid coupling between the symmetric and anti-symmetric modes supported by the composite structure consisting of dielectric waveguide and the thin metallic plasmonic waveguide. Periodic coupling between the symmetric and anti-symmetric hybrid modes takes place, and varies with the length of the sensor. The attained numerical results show that for a properly optimized metal and buffer layer thicknesses, a sensitivity of dB/RIU and resolution of RIU can be achieved for aqueous environment, which to our knowledge, are the highest obtained so far.
Autors: Divya Madaan;A. Kapoor;V. K. Sharma;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:2, pages: 149 - 152
Publisher: IEEE
 
» Ultraino: An Open Phased-Array System for Narrowband Airborne Ultrasound Transmission
Abstract:
Modern ultrasonic phased-array controllers are electronic systems capable of delaying the transmitted or received signals of multiple transducers. Configurable transmit–receive array systems, capable of electronic steering and shaping of the beam in near real-time, are available commercially, for example, for medical imaging. However, emerging applications, such as ultrasonic haptics, parametric audio, or ultrasonic levitation, require only a small subset of the capabilities provided by the existing controllers. To meet this need, we present Ultraino, a modular, inexpensive, and open platform that provides hardware, software, and example applications specifically aimed at controlling the transmission of narrowband airborne ultrasound. Our system is composed of software, driver boards, and arrays that enable users to quickly and efficiently perform research in various emerging applications. The software can be used to define array geometries, simulate the acoustic field in real time, and control the connected driver boards. The driver board design is based on an Arduino Mega and can control 64 channels with a square wave of up to 17 Vpp and /5 phase resolution. Multiple boards can be chained together to increase the number of channels. The 40-kHz arrays with flat and spherical geometries are demonstrated for parametric audio generation, acoustic levitation, and haptic feedback.
Autors: Asier Marzo;Tom Corkett;Bruce W. Drinkwater;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Jan 2018, volume: 65, issue:1, pages: 102 - 111
Publisher: IEEE
 
» Ultrasound Detection Using Acoustic Apertures
Abstract:
Ultrasound detection is commonly performed by piezoelectric transducers that are optimized for a specific application. Since the piezoelectric technology is not configurable, transducers designed for one application may not be compatible with other applications. In addition, some designs of ultrasound transducers may be difficult to implement owing to production constraints. In this paper, we propose a simple, low-cost method to reconfigure the geometry of ultrasound transducers. The technique is based on using apertures in thin sheets of acoustic blockers. We experimentally demonstrate this method for an ultrasound transducer with a central frequency of 1 MHz and show that it can emulate detectors of various sizes. An added advantage of this technique is its capability to achieve semi-isotropic detection sensitivity due to diffraction when the aperture size is comparable to the acoustic wavelength even when the angular sensitivity of the transducer is inherently limited.
Autors: Evgeny Hahamovich;Amir Rosenthal;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Jan 2018, volume: 65, issue:1, pages: 120 - 126
Publisher: IEEE
 
» Ultrathin-Barrier AlGaN/GaN Heterostructure: A Recess-Free Technology for Manufacturing High-Performance GaN-on-Si Power Devices
Abstract:
(Al)GaN recess-free normally OFF technology is developed for fabrication of high-yield lateral GaN-based power devices. The recess-free process is achieved by an ultrathin-barrier (UTB) AlGaN/GaN heterostructure that features a natural pinched-off 2-D electron gas channel. The top–down manufacturing technique overcomes the challenges in etching of AlGaN barrier with well-controlled depth and uniformity, which is especially attractive for fabrication of normally OFF GaN-based high-electron-mobility transistors (HEMTs) and metal–insulator–semiconductor HEMTs (MIS-HEMTs) on large-size Si substrate. With SiNx passivation grown by low-pressure chemical-vapor deposition, on-resistance of the UTB-AlGaN/GaN-based power devices can be significantly reduced. High-uniformity low-hysteresis normally OFF HEMTs and Al2O3/AlGaN/GaN MIS-HEMTs are successfully demonstrated on the UTB AlGaN/GaN-on-Si platform. It is also a compelling technology platform for manufacturing high-performance GaN-based lateral power diodes, and normally OFF p-(Al)GaN heterojunction field-effect transistors.
Autors: Sen Huang;Xinyu Liu;Xinhua Wang;Xuanwu Kang;Jinhan Zhang;Jie Fan;Jingyuan Shi;Ke Wei;Yingkui Zheng;Hongwei Gao;Qian Sun;Maojun Wang;Bo Shen;Kevin J. Chen;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2018, volume: 65, issue:1, pages: 207 - 214
Publisher: IEEE
 
» Unbiased Charged Circular CMUT Microphone: Lumped-Element Modeling and Performance
Abstract:
An energy-consistent lumped-element equivalent circuit model for charged circular capacitive micromachined ultrasonic transducer (CMUT) cell is derived and presented. It is analytically shown and experimentally verified that a series dc voltage source at the electrical terminals is sufficient to model the charging in CMUT. A model-based method for determining this potential from impedance measurements at low bias voltages is presented. The model is validated experimentally using an airborne CMUT, which resonates at 103 kHz. Impedance measurements, reception measurements at resonance and off-resonance, and the transient response of the CMUT are compared with the model predictions.
Autors: Hayrettin Köymen;Abdullah Atalar;Saadettin Güler;Itır Köymen;A. Sinan Taşdelen;Aslı Ünlügedik;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Jan 2018, volume: 65, issue:1, pages: 60 - 71
Publisher: IEEE
 
» Uncertain Power Flow Analysis Based on Evidence Theory and Affine Arithmetic
Abstract:
A novel uncertain power flow analysis method is proposed in this letter. It utilizes evidence theory to fuse probabilistic, possibilistic, and interval uncertainties. Besides, the extended affine arithmetic is applied to handle variable dependencies existed in power flow. The final analysis results are represented as probability boxes (p-boxes). The comparisons with Monte Carlo simulation are given to demonstrate the validity of the proposed method.
Autors: Jinqing Luo;Libao Shi;Yixin Ni;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2018, volume: 33, issue:1, pages: 1113 - 1115
Publisher: IEEE
 
» Uncertainty Visualization Using Copula-Based Analysis in Mixed Distribution Models
Abstract:
Distributions are often used to model uncertainty in many scientific datasets. To preserve the correlation among the spatially sampled grid locations in the dataset, various standard multivariate distribution models have been proposed in visualization literature. These models treat each grid location as a univariate random variable which models the uncertainty at that location. Standard multivariate distributions (both parametric and nonparametric) assume that all the univariate marginals are of the same type/family of distribution. But in reality, different grid locations show different statistical behavior which may not be modeled best by the same type of distribution. In this paper, we propose a new multivariate uncertainty modeling strategy to address the needs of uncertainty modeling in scientific datasets. Our proposed method is based on a statistically sound multivariate technique called Copula, which makes it possible to separate the process of estimating the univariate marginals and the process of modeling dependency, unlike the standard multivariate distributions. The modeling flexibility offered by our proposed method makes it possible to design distribution fields which can have different types of distribution (Gaussian, Histogram, KDE etc.) at the grid locations, while maintaining the correlation structure at the same time. Depending on the results of various standard statistical tests, we can choose an optimal distribution representation at each location, resulting in a more cost efficient modeling without significantly sacrificing on the analysis quality. To demonstrate the efficacy of our proposed modeling strategy, we extract and visualize uncertain features like isocontours and vortices in various real world datasets. We also study various modeling criterion to help users in the task of univariate model selection.
Autors: Subhashis Hazarika;Ayan Biswas;Han-Wei Shen;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 934 - 943
Publisher: IEEE
 
» Under the Covers of IEEE Software
Abstract:
Ecosystems that thrive are those whose members contribute more than they take away. Judging by the growth of its offerings and volunteers, IEEE Software is clearly such a case: over the past year, more than 1,500 people have contributed to it as authors, reviewers, editors, podcast hosts and guests, advisors, curators, and many other roles. Here, Editor in Chief Diomidis Spinellis discusses what makes Software tick and how can you participate in its community of volunteers.
Autors: Diomidis Spinellis;
Appeared in: IEEE Software
Publication date: Jan 2018, volume: 35, issue:1, pages: 4 - 7
Publisher: IEEE
 
» Undersea data monster
Abstract:
When a new undersea communications cable becomes operational late this year, it will break the record for a key metric: data rate times distance. In a single second, its six fiber-optic pairs, stretching roughly 13,000 kilometers (8,000 miles) between Hong Kong and Los Angeles, will be able to send some 144 terabits in both directions. That's as much data as you’d find in several hundred Blu-ray discs. The cable's main purpose is to connect Facebook and Google data centers in East Asia with those in the United States.
Autors: Jeff Hecht;
Appeared in: IEEE Spectrum
Publication date: Jan 2018, volume: 55, issue:1, pages: 36 - 39
Publisher: IEEE
 
» Understanding a Sequence of Sequences: Visual Exploration of Categorical States in Lake Sediment Cores
Abstract:
This design study focuses on the analysis of a time sequence of categorical sequences. Such data is relevant for the geoscientific research field of landscape and climate development. It results from microscopic analysis of lake sediment cores. The goal is to gain hypotheses about landscape evolution and climate conditions in the past. To this end, geoscientists identify which categorical sequences are similar in the sense that they indicate similar conditions. Categorical sequences are similar if they have similar meaning (semantic similarity) and appear in similar time periods (temporal similarity). For data sets with many different categorical sequences, the task to identify similar sequences becomes a challenge. Our contribution is a tailored visual analysis concept that effectively supports the analytical process. Our visual interface comprises coupled visualizations of semantics and temporal context for the exploration and assessment of the similarity of categorical sequences. Integrated automatic methods reduce the analytical effort substantially. They (1) extract unique sequences in the data and (2) rank sequences by a similarity measure during the search for similar sequences. We evaluated our concept by demonstrations of our prototype to a larger audience and hands-on analysis sessions for two different lakes. According to geoscientists, our approach fills an important methodological gap in the application domain.
Autors: Andrea Unger;Nadine Dräger;Mike Sips;Dirk J. Lehmann;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 66 - 76
Publisher: IEEE
 
» Understanding the Relationship Between Interactive Optimisation and Visual Analytics in the Context of Prostate Brachytherapy
Abstract:
The fields of operations research and computer science have long sought to find automatic solver techniques that can find high-quality solutions to difficult real-world optimisation problems. The traditional workflow is to exactly model the problem and then enter this model into a general-purpose “black-box” solver. In practice, however, many problems cannot be solved completely automatically, but require a “human-in-the-loop” to iteratively refine the model and give hints to the solver. In this paper, we explore the parallels between this interactive optimisation workflow and the visual analytics sense-making loop. We assert that interactive optimisation is essentially a visual analytics task and propose a problem-solving loop analogous to the sense-making loop. We explore these ideas through an in-depth analysis of a use-case in prostate brachytherapy, an application where interactive optimisation may be able to provide significant assistance to practitioners in creating prostate cancer treatment plans customised to each patient's tumour characteristics. However, current brachytherapy treatment planning is usually a careful, mostly manual process involving multiple professionals. We developed a prototype interactive optimisation tool for brachytherapy that goes beyond current practice in supporting focal therapy - targeting tumour cells directly rather than simply seeking coverage of the whole prostate gland. We conducted semi-structured interviews, in two stages, with seven radiation oncology professionals in order to establish whether they would prefer to use interactive optimisation for treatment planning and whether such a tool could improve their trust in the novel focal therapy approach and in machine generated solutions to the problem.
Autors: Jie Liu;Tim Dwyer;Kim Marriott;Jeremy Millar;Annette Haworth;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Jan 2018, volume: 24, issue:1, pages: 319 - 329
Publisher: IEEE
 
» Uniform-Field Over-Mode Waveguide for Spatial Power-Combining Applications
Abstract:
A new and effective millimeter-wave waveguide packaging technique suitable for 1-D spatial power-combining applications is presented. The transition structure using narrow corporate channels preserves the uniform field distribution when expanding the -plane width of a standard waveguide to several wavelengths. A Q-band test module, containing back-to-back transitions for an increased width from 2.84 to 52 mm, shows an average insertion loss of 0.34 dB in the 40–50-GHz range. The radiation patterns from an open-end module, cut in half from the original test module, confirm uniform field distribution across the over-mode guide aperture.
Autors: C. Yi;H. Lee;K. J. Lee;J. H. Joo;J. B. Kwon;M. Kim;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2018, volume: 28, issue:1, pages: 10 - 12
Publisher: IEEE
 
» Unipolar Modulation for a BLDC Motor With Simultaneously Switching of Two Transistors With Closed Loop Control for Four-Quadrant Operation
Abstract:
The paper describes a method of unipolar modulation that permits easy transition from motor to generator operation mode of a brush-less direct-current (BLDC) machine. This method is characterized by simultaneous switching of both transistors, which yields an increased frequency of current ripple component, when in a typical unipolar modulation only one transistor is switched. A BLDC motor control system is also presented, which reflects the idea of a logic rectifier for the determination of an equivalent dc value. The described modulation methods and control systems constitute a coherent conception of digital control for the BLDC motor operation.
Autors: Marcin Baszynski;Stanislaw Pirog;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Jan 2018, volume: 14, issue:1, pages: 146 - 155
Publisher: IEEE
 
» Unitary Polynomial Propagator Solving Maxwell’s Equations Allowing Arbitrarily Large Time Steps
Abstract:
A novel fully explicit vectorial time-domain algorithm for the analysis of photonic devices capable of solving Maxwell’s equations with arbitrarily large time steps is presented. Furthermore, the time-domain propagation algorithm ensures energy conservation and stability. For this purpose, a unitary time-domain propagation scheme is defined by a suitable polynomial expansion of the propagator.
Autors: Hendrik Kleene;Dirk Schulz;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2018, volume: 30, issue:2, pages: 193 - 196
Publisher: IEEE
 
» Universal Custom Complex Magnetic Spring Design Methodology
Abstract:
A design methodology is presented for creating custom complex magnetic springs through the design of force-displacement curves. This methodology results in a magnet configuration, which will produce a desired force-displacement relationship. Initially, the problem is formulated and solved as a system of linear equations. Then, given the limited likelihood of a single solution being feasibly manufactured, key parameters of the solution are extracted and varied to create a family of solutions. Finally, these solutions are refined using numerical optimization. Given the properties of magnets, this methodology can create any well-defined function of force versus displacement and is model-independent. To demonstrate this flexibility, a number of example magnetic springs are designed; one of which, designed for use in a jumping–gliding robot’s shape memory alloy actuated clutch, is manufactured and experimentally characterized. Due to the scaling of magnetic forces, the displacement region which these magnetic springs are most applicable is that of millimeters and below. However, this region is well situated for miniature robots and smart material actuators, where a tailored magnetic spring, designed to compliment a component, can enhance its performance while adding new functionality. The methodology is also expendable to variable interactions and multi-dimensional magnetic field design.
Autors: Matthew A. Woodward;Metin Sitti;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2018, volume: 54, issue:1, pages: 1 - 13
Publisher: IEEE
 
» Unsupervised Classification of PolSAR Data Using a Scattering Similarity Measure Derived From a Geodesic Distance
Abstract:
In this letter, we propose a novel technique for obtaining scattering components from polarimetric synthetic aperture radar (PolSAR) data using the geodesic distance on the unit sphere. This geodesic distance is obtained between an elementary target and the observed Kennaugh matrix, and it is further utilized to compute a similarity measure between scattering mechanisms. The normalized similarity measure for each elementary target is then modulated with the total scattering power (Span). This measure is used to categorize pixels into three categories, i.e., odd-bounce, double-bounce, and volume, depending on which of the above scattering mechanisms dominate. Then the maximum likelihood classifier of Lee et al. based on the complex Wishart distribution is iteratively used for each category. Dominant scattering mechanisms are thus preserved in this classification scheme. We show results for L-band AIRSAR and ALOS-2 data sets acquired over San Francisco and Mumbai, respectively. The scattering mechanisms are better preserved using the proposed methodology than the unsupervised classification results using the Freeman–Durden scattering powers on an orientation angle corrected PolSAR image. Furthermore: 1) the scattering similarity is a completely nonnegative quantity unlike the negative powers that might occur in double-bounce and odd-bounce scattering component under Freeman–Durden decomposition and 2) the methodology can be extended to more canonical targets as well as for bistatic scattering.
Autors: Debanshu Ratha;Avik Bhattacharya;Alejandro C. Frery;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2018, volume: 15, issue:1, pages: 151 - 155
Publisher: IEEE
 

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