Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 10

» Loss of low-frequency data in on- line frequency response analysis of transformers
Abstract:
Power transformers are a key component of the electricity supply grid. Monitoring and assessment of their condition has always been of great concern [1]. In critical situations, transformer failures can cause irreversible damage and considerable financial loss to the grid stakeholders or even the end-users [2], [3]. In this regard, mechanical defects are considered a major problem in distribution and power transformers [4]. Consequently various diagnostic techniques have been developed to identify transformer mechanical defects and winding deformation.
Autors: Mehdi Bagheri;Svyatoslav Nezhivenko;B. T. Phung;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Sep 2017, volume: 33, issue:5, pages: 32 - 39
Publisher: IEEE
 
» Low Complexity Post-Distorter for Visible Light Communications
Abstract:
In this letter, a visible light communication (VLC) link affected by the light emitting diode (LED) nonlinearity and dispersion due to the IEEE 802.15 PAN channel impulse response is considered. To mitigate severe intersymbol interference and LED nonlinearity, computationally complex classical post-distortion techniques fall short in terms of applicability to massively connected 5G deployments (as in a VLC attocell) due to increased demand on resources and intractability of implementation. To address these issues, this letter proposes a low-complexity reproducing kernel Hilbert space-based post-distorter using a better sparsification technique equipped with an adaptive kernel width optimized by a minimum symbol error rate (MSER) criterion. Use of the proposed MSER metric for kernel width optimization reduces the computational complexity at the receiver, without compromising on the bit error rate. An upper bound on step-size to guarantee convergence of the proposed post-distorter is analytically derived, and the steady-state mean square error is also analyzed theoretically and validated by simulations. Furthermore, analytical upper bounds for bit error rate and steady-state dictionary size are also derived.
Autors: Rangeet Mitra;Vimal Bhatia;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 1977 - 1980
Publisher: IEEE
 
» Low Rank Approximation and Decomposition of Large Matrices Using Error Correcting Codes
Abstract:
Low rank approximation is an important tool used in many applications of signal processing and machine learning. Recently, randomized sketching algorithms were proposed to effectively construct low rank approximations and obtain approximate singular value decompositions of large matrices. Similar ideas were used to solve least squares regression problems. In this paper, we show how matrices from error correcting codes can be used to find such low rank approximations and matrix decompositions, and extend the framework to linear least squares regression problems. The benefits of using these code matrices are the following. First, they are easy to generate and they reduce randomness significantly. Second, code matrices, with mild restrictions, satisfy the subspace embedding property, and have a better chance of preserving the geometry of an large subspace of vectors. Third, for parallel and distributed applications, code matrices have significant advantages over structured random matrices and Gaussian random matrices. Fourth, unlike Fourier or Hadamard transform matrices, which require sampling columns for a rank- approximation, the log factor is not necessary for certain types of code matrices. In particular, optimal Frobenius norm error can be achieved for a rank- approximation with samples. Fifth, fast multiplication is possible with structured code matrices, so fast approximations can be achieved for general dense input matrices. Sixth, for least squares regression problem , the relative error approximation can be achieved with samples, with high probability, when certain code matrices are used.
Autors: Shashanka Ubaru;Arya Mazumdar;Yousef Saad;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5544 - 5558
Publisher: IEEE
 
» Low-Complexity Base Station Selection Scheme in mmWave Cellular Networks
Abstract:
In this paper, we study the performance of next-generation cellular networks in the context of a low-complexity base station (BS) selection scheme. In contrast to existing BS cooperation approaches, where multiple BSs jointly transmit to the user, by using our proposed low-complexity technique, a user communicates with the BS that provides the maximum signal-to-interference-plus-noise-ratio from a set formed according to a pre-selection policy. We consider three pre-selection policies based on: 1) the Euclidean distance; 2) the averaged received power; and 3) a random selection. Moreover, we consider the case where the users have the ability to employ the successive interference cancellation (SIC) scheme. Despite its high computational complexity, SIC can potentially decode and remove strong interfering signals from the aggregate received signal, which can significantly boost the user’s performance. By using stochastic geometry tools, analytical expressions for the coverage performance are derived for each policy, by taking into account spatial randomness and blockage effects. Our proposed technique provides low computational and implementation complexity due to the two-level selection scheme. Furthermore, we show that our proposed scheme does not lose in diversity compared with existing cooperation techniques and that all policies can benefit by the employment of the SIC scheme.
Autors: Christodoulos Skouroumounis;Constantinos Psomas;Ioannis Krikidis;
Appeared in: IEEE Transactions on Communications
Publication date: Sep 2017, volume: 65, issue:9, pages: 4049 - 4064
Publisher: IEEE
 
» Low-Complexity Message-Passing Cooperative Localization in Wireless Sensor Networks
Abstract:
This letter proposes a low-complexity message-passing cooperative localizer for wireless sensor networks with (un-)quantized time-of-arrival (TOA) measurements. The collaborative positioning problem is first converted as a generalized nonlinear mixing problem, and then resolved by our developed extended generalized approximate message passing (EGAMP) algorithm. The EGAMP localizer iterates between Taylor expanding the nonlinear mixing problem as a linear mixing one, and recovering positions by one-step GAMP. It successfully handles the quantization losses of quantized TOAs. Its computational complexity is three orders lower than that of belief propagation localizers. Based on our experimental results, the EGAMP localizer gives the state-of-the-art positioning performances, and is robust to quantization losses.
Autors: Shengchu Wang;Feng Luo;Xiaojun Jing;Lin Zhang;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 2081 - 2084
Publisher: IEEE
 
» Low-Complexity Model Predictive Stator Current Control of DFIG Under Harmonic Grid Voltages
Abstract:
This paper proposes a low-complexity model predictive stator current control (LC-MPSCC) strategy of the doubly fed induction generator (DFIG) under harmonic grid voltage conditions. Sinusoidal stator currents are ensured to be injected into the power grid due to the direct control of the stator currents rather than the rotor currents. No extractions of harmonic voltages or currents are needed in the proposed LC-MPSCC strategy. Conventional resonant regulators that are usually adopted to eliminate the harmonic components in the stator currents are also avoided. Thus, the control system complexity can be decreased. To reduce the iterative computation process in the predictive control strategy, a low-complexity method is designed and only two predictions are needed, which is much smaller than the conventional predictive control that needs seven predictions in a two-level three-phase inverter. The low-complexity method enables higher sampling frequency for better steady performance. Finally, simulation and experimental results on a 1-kW DFIG system are provided to validate the effectiveness of the LC-MPSCC strategy.
Autors: Chenwen Cheng;Heng Nian;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1072 - 1080
Publisher: IEEE
 
» Low-Complexity Semiblind Channel Estimation in Massive MU-MIMO Systems
Abstract:
Massive multi-user multiple-input multiple-output (MU-MIMO) systems are a promising solution for achieving high throughput and robust transmission in next generation mobile communications. Achieving the optimal transceiver design in such systems requires an accurate knowledge of the channel state information. However, in massive MU-MIMO systems, the quality of the channel estimates is often degraded by pilot contamination. In this paper, we propose a low-complexity semiblind channel estimation algorithm to mitigate the ill effects of pilot contamination. In the proposed approach, the received signals are first projected onto the subspace with minimal interference, where the bases of this subspace are determined recursively via a low-complexity modified power method. An initial estimate of the projected channel coefficients is then made based on a small number of pilot symbols. Finally, data symbols are detected and the channel estimation is refined alternatively. Compared with existing channel estimation methods, the proposed algorithm has lower complexity due to the subspace projection and innovation process. An asymptotic analysis reveals that the mean square error of the channel estimates is inversely proportional to the length of the data symbols. Simulation results demonstrate that the proposed algorithm outperforms the existing works and alleviates the pilot contamination effects effectively.
Autors: Chao-Yi Wu;Wan-Jen Huang;Wei-Ho Chung;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 6279 - 6290
Publisher: IEEE
 
» Low-Complexity Soft-Decision Concatenated LDGM-Staircase FEC for High-Bit-Rate Fiber-Optic Communication
Abstract:
A concatenated soft-decision forward error correction (FEC) scheme consisting of an inner low-density generator-matrix (LDGM) code and an outer staircase code is proposed. The soft-decision LDGM code is used for error reduction, while the majority of bit errors are corrected by the low-complexity hard-decision staircase code. Decoding complexity of the concatenated code is quantified by a score based on the number of edges in the LDGM code Tanner graph, the number of decoding iterations, and the number of staircase code decoding operations. The inner LDGM ensemble is designed by solving an optimization problem, which minimizes the product of the average node degree and an estimate of the required number of decoding iterations. A search procedure is used to find the inner and outer code pair with lowest complexity. The design procedure results in a Pareto-frontier characterization of the tradeoff between net coding gain and complexity for the concatenated code. Simulations of code designs at overhead showed that the proposed scheme achieves net coding gains equivalent to existing soft-decision FEC solutions, with up to reduction in complexity.
Autors: Lei M. Zhang;Frank R. Kschischang;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:18, pages: 3991 - 3999
Publisher: IEEE
 
» Low-Gain Integral Control for Multi-Input Multioutput Linear Systems With Input Nonlinearities
Abstract:
We consider the inclusion of a static antiwindup component in a continuous-time low-gain integral controller in feedback with a multi-input multi-output stable linear system subject to an input nonlinearity (from a class of functions that includes componentwise diagonal saturation). We demonstrate that the output of the closed-loop system asymptotically tracks every constant reference vector, which is “feasible” in a natural sense, provided that the integrator gain is sufficiently small. Robustness properties of the proposed control scheme are investigated and three examples are discussed in detail.
Autors: Chris Guiver;Hartmut Logemann;Stuart Townley;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4776 - 4783
Publisher: IEEE
 
» Low-Leakage ESD Power Clamp Design With Adjustable Triggering Voltage for Nanoscale Applications
Abstract:
A low-leakage electrostatic discharge power clamp with adjustable triggering voltage ( is proposed in this paper. By enabling the static detection path using the transient one, the proposed clamp achieves a wide range of adjustable while maintaining low standby leakage current (, which overcomes the flaw of traditional static clamps. Besides, the adjustable with low is attractive for nanoscale applications. Moreover, the proposed clamp achieves enhanced false-triggering immunity over traditional transient clamps. The proposed clamp is successfully verified in a 65-nm CMOS process. Aside from silicon verifications, detailed comparisons with prior arts and practical application concerns are also addressed in this paper.
Autors: Guangyi Lu;Yuan Wang;Yize Wang;Xing Zhang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3569 - 3575
Publisher: IEEE
 
» Low-Loss SOI-LIGBT With Triple Deep-Oxide Trenches
Abstract:
A novel 500-V silicon-on-insulator lateral insulated gate bipolar transistor (SOI-LIGBT) is proposed for the first time in this paper. The device features triple deep-oxide trenches (TDOT) arranged in the drift region. The depths of the trenches near the emitter side ( and near the collector side ( are shallower than that of the trench ( located in the silicon region between and . Compared with a reported SOI-LIGBT with dual deep-oxide trenches (DDOT), the shallow trench near the emitter side ( in the proposed TDOT SOI-LIGBT alleviates the JFET effect between the P-body region and , resulting in a lower on-state voltage drop (. In the off-state, the electric potential sustained by the TDOT is higher than that of the DDOT. At the same breakdown voltage of 560 V, the length of silicon region between and N-buffer region ( is reduced from for the DDOT SOI-LIGBT to for the proposed TDOT SOI-LIGB- , indicating a smaller number of stored carries at the collector side and thereby a faster turn-off in the proposed TDOT SOI-LIGBT. The experiments demonstrate that the proposed TDOT SOI-LIGBT achieves turn-off loss (% lower than the DDOT SOI-LIGBT at the same of 1.53 V.
Autors: Long Zhang;Jing Zhu;Minna Zhao;Siyang Liu;Weifeng Sun;Longxing Shi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3756 - 3761
Publisher: IEEE
 
» Low-Power LDPC-CC Decoding Architecture Based on the Integration of Memory Banks
Abstract:
This brief proposes a low-power low-density parity check convolutional code (LDPC-CC) decoder that is fully compatible with the IEEE 1901 standard. The proposed architecture merges multiple memory banks into one to make it consume much less power than the conventional architecture. Memory operations conducted by all the unit processors are synchronized in the proposed decoder to merge the memory and avoid any possible data hazard. The data hazard happens when a unit processor tries to read a log-likelihood ratio before a different processor updates it, degrading the error-correcting performance. Memory-access patterns appearing in a memory-based LDPC-CC decoder are formulated to determine the size of a sliding window adequate for decoding. Experimental results show that the decoding architecture employing the merged memory and the proper window size reduces the power consumption by up to 40% compared to the conventional architecture that employs multiple memory banks.
Autors: Injae Yoo;In-Cheol Park;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2017, volume: 64, issue:9, pages: 1057 - 1061
Publisher: IEEE
 
» Low-Profile High-Power Optically Addressed Phased Array Antenna
Abstract:
A low-profile optically fed ultra-wideband-connected array (CA) antenna with increased operational power is presented. Introduction of a miniature optical prism into the fiber optic feed enables an efficient 90° coupling to a high-power charge-compensated-modified uni-travelling carrier photodiode connected directly at the feed point of an integrated CA antenna element. This technique significantly reduces the array profile and, herein, is implemented into a 1-D CA antenna array consisting of eight photodiode-coupled active dipole elements. The experimentally verified array achieves effective beamforming and beam steering over a 3-dB bandwidth of 6–17 GHz, as well as a peak effective isotropic radiated power of 27.5 dBm at 13 GHz.
Autors: Dylan D. Ross;Matthew R. Konkol;Shouyuan Shi;Charles E. Harrity;Andrew A. Wright;Christopher A. Schuetz;Dennis W. Prather;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:18, pages: 3894 - 3900
Publisher: IEEE
 
» Low-Temperature Characterization of Cu–Cu:Silica-Based Programmable Metallization Cell
Abstract:
In this letter, low-temperature characterization of Cu–Cu:silica programmable metallization cells (PMC) is presented. Our results show that the PMC device is functional even at 4 K and that the low resistance state is essentially unaffected by temperature whereas the high resistance state increases with decreasing temperature. A direct tunneling model is applied to explain the temperature independent low-resistance state.
Autors: W. Chen;N. Chamele;Y. Gonzalez-Velo;H. J. Barnaby;M. N. Kozicki;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1244 - 1247
Publisher: IEEE
 
» Low-Temperature Solution-Based In2O3 Channel Formation for Thin-Film Transistors Using a Visible Laser-Assisted Combustion Process
Abstract:
This letter reports the low-temperature solution-based fabrication of indium oxide (In2O3) thin-film transistors (TFTs) using a visible laser-assisted urea combustion process. An In2O3 precursor solution containing a small amount of urea absorbed the photon energy from a blue laser and started the combustion of urea to form a crystallized In2O3 phase. Atomic force microscopy and X-ray diffraction showed that both laser radiation and urea combustion together are necessary to convert a dried precursor solution layer to a crystallized In2O3 phase. A TFT fabricated from the 0.2-mol% urea-added solution and laser annealed with a 250-J/cm energy fluence exhibited superior transfer characteristics compared with the TFTs fabricated either without urea addition or with small energy fluence radiation. Based on these results and considering the price of blue laser diodes, this technique can be an economical solution for the fabrication of oxide semiconductor TFTs on flexible substrates with a low melting point.
Autors: Jae-Won Choi;Soo-Yeun Han;Manh-Cuong Nguyen;An Hoang-Thuy Nguyen;Jung Yeon Kim;Sujin Choi;Jonggyu Cheon;Hyungmin Ji;Rino Choi;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1259 - 1262
Publisher: IEEE
 
» Lower Bounds on the Size of Smallest Elementary and Non-Elementary Trapping Sets in Variable-Regular LDPC Codes
Abstract:
Trapping sets are known to be the main cause for the error floor of low-density parity-check (LDPC) codes. They are often classified by their size and the number of unsatisfied check nodes in their subgraph. Trapping sets can be partitioned into two categories of elementary and non-elementary, where the first category are those whose subgraph only contains degree-1 and degree-2 check nodes. Empirical results have shown that often the most harmful trapping sets are elementary. In this letter, we derive a lower bound on the size of the smallest non-elementary trapping sets for a given in variable-regular LDPC codes. The derived lower bound demonstrates that the size of the smallest possible non-elementary trapping set is, in general, larger than that of an elementary trapping set with the same value. This provides a theoretical justification as to why non-elementary trapping sets are often not among the most harmful trapping sets.
Autors: Yoones Hashemi;Amir H. Banihashemi;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 1905 - 1908
Publisher: IEEE
 
» LS-Join: Local Similarity Join on String Collections
Abstract:
String similarity join, as an essential operation in applications including data integration and data cleaning, has attracted significant attention in the research community. Previous studies focus on global similarity join. In this paper, we study local similarity join with edit distance constraints, which finds string pairs from two string collections that have similar substrings. We study two kinds of local similarity join problems: checking local similar pairs and locating local similar pairs. We first consider the case where if two strings are locally similar to each other, they must share a common gram of a certain length. We show how to do efficient local similarity verification based on a matching gram pair. We propose two pruning techniques and an incremental method to further improve the efficiency of finding matching gram pairs. Then, we devise a method to locate the longest similar substring pair for two local similar strings. We conducted a comprehensive experimental study to evaluate the efficiency of these techniques.
Autors: Jiaying Wang;Xiaochun Yang;Bin Wang;Chengfei Liu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 1928 - 1942
Publisher: IEEE
 
» Lung Ultrasound Surface Wave Elastography: A Pilot Clinical Study
Abstract:
A lung ultrasound surface wave elastography (LUSWE) technique is developed to measure superficial lung tissue elastic properties. The purpose of this paper was to translate LUSWE into clinical studies for assessing patients with interstitial lung disease (ILD) and present the pilot data from lung measurements on 10 healthy subjects and 10 patients with ILD. ILD includes multiple lung disorders in which the lung tissue is distorted and stiffened by tissue fibrosis. Chest radiography and computed tomography are the most commonly used techniques for assessing lung disease, but they are associated with radiation and cannot directly measure lung elastic properties. LUSWE provides a noninvasive and nonionizing technique to measure the elastic properties of superficial lung tissue. LUSWE was used to measure regions of both lungs through six intercostal spaces for patients and healthy subjects. The data are presented as wave speed at 100, 150, and 200 Hz at the six intercostal spaces. As an example, the surface wave speeds are, respectively, 1.88 ± 0.11 m/s at 100 Hz, 2.74 ± 0.26 m/s at 150 Hz, and 3.62 ± 0.13 m/s at 200 Hz for a healthy subject in the upper right lung; this is in comparison to measurements from an ILD patient of 3.3 ± 0.37 m/s at 100 Hz, 4.38 ± 0.33 m/s at 150 Hz, and 5.24 ± 0.44 m/s at 200 Hz in the same lung space. Significant differences in wave speed between healthy subjects and ILD patients were found. LUSWE is a safe and noninvasive technique which may be useful for assessing ILD.
Autors: Xiaoming Zhang;Thomas Osborn;Boran Zhou;Duane Meixner;Randall R. Kinnick;Brian Bartholmai;James F. Greenleaf;Sanjay Kalra;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2017, volume: 64, issue:9, pages: 1298 - 1304
Publisher: IEEE
 
» Magnetic Field Analysis in Shell-Like Spherical Induction Machines with Zenithal Traveling Waves
Abstract:
In this paper, a magnetic field analysis is done for spherical shell-like induction machines with a zenithal progressive magnetic traveling wave, using an analytical model in spherical coordinates. These analytical models have major importance in the simulation, project, and preliminary optimization of devices due to its analytical solutions and physical insight. The magnetic field analysis is made for a shell-like induction machine for the study of its electromagnetic and mechanical quantities, as the magnetic field, induced currents, and electromagnetic torque. The developed model is validated, first with a set of generic windings distributions using the results of a commercial finite element analysis (FEA) tool and, second, validated by comparing with the results from the shell-like induction machine prototype. The results obtained from the analytical model are very close to the ones obtained by the FEA tool and from the prototype tests.
Autors: João Filipe Pereira Fernandes;Vitor Maló Machado;Paulo J. Costa Branco;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1081 - 1089
Publisher: IEEE
 
» Magnetic Field Characteristics of Wet Belt Permanent High Gradient Magnetic Separator and Its Full-Scale Purification for Garnet Ore
Abstract:
Purification of non-metallic ores has received considerable attention in the recent decade. In this investigation, the magnetic field characteristics of the innovative plate-type permanent magnet in wet belt permanent high gradient magnetic separator (WBHGMS) were analyzed; then, its full-scale purification of a garnet ore was introduced, and its performance dependences on the key operational parameters, i.e., magnet length, belt rotation speed, and feed particle size, were respectively examined. The separator produced a high-quality non-magnetic product assaying 2.00% Fe at an iron removal rate of 95.00% from the ore assaying 13.10% Fe. It was thus concluded that this WBHGMS separator has provided a promising method for the purification of non-metallic ores.
Autors: Luzheng Chen;Yongming Zheng;Jianwu Zeng;Yongxing Zheng;Jian Liu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 5
Publisher: IEEE
 
» Major Trends Impacting Power Systems [From the Editor's Desk]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Lanny Floyd;
Appeared in: IEEE Industry Applications Magazine
Publication date: Sep 2017, volume: 23, issue:5, pages: 3 - 3
Publisher: IEEE
 
» Making VTM Ever More Exciting [From the Editor]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Klaus David;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Sep 2017, volume: 12, issue:3, pages: 3 - 3
Publisher: IEEE
 
» Managing Temporal Constraints with Preferences: Representation, Reasoning, and Querying
Abstract:
Representing and managing temporal knowledge, in the form of temporal constraints, is a crucial task in many areas, including knowledge representation, planning, and scheduling. The current literature in the area is moving from the treatment of “crisp” temporal constraints to fuzzy or probabilistic constraints, to account for preferences and\or uncertainty. Given a set of temporal constraints, the evaluation of the tightest implied constraints is a fundamental task, which is essential also to provide reliable query-answering facilities. However, while such tasks have been widely addressed for “crisp” temporal constraints, they have not attracted enough attention in the “non-crisp” context yet. We overcome such a limitation, by (i) extending quantitative temporal constraints to cope with preferences, (ii) defining a temporal reasoning algorithm which evaluates the tightest temporal constraints, and (iii) providing suitable query-answering facilities based on it.
Autors: Paolo Terenziani;Antonella Andolina;Luca Piovesan;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 2067 - 2071
Publisher: IEEE
 
» Mandatory Content Access Control for Privacy Protection in Information Centric Networks
Abstract:
Several Information Centric Network (ICN) architectures have been proposed as candidates for the future Internet, aiming to solve several salient problems in the current IP-based Internet architecture such as mobility, content dissemination and multi-path forwarding. In general, security and privacy are considered as essential requirements in ICN. However, existing ICN designs lack built-in privacy protection for content providers (CPs), e.g., any router in an Internet Service Provider in ICN can cache any content, which may result in information leakage. In this paper, we propose Mandatory Content Access Control (MCAC), a distributed information flow control mechanism to enable a content provider to control which network nodes can cache its contents. In MCAC, a CP defines different security labels for different contents, and content routers check these labels to decide if a content object should be cached. To ensure correct enforcement of MCAC, we also propose a design of a trusted architecture by extending existing mainstream router architectures. We evaluate the performance of MCAC in the NS-3 simulator. The simulation results show that enforcing MCAC in routers does not introduce significant overhead in content forwarding.
Autors: Qi Li;Ravi Sandhu;Xinwen Zhang;Mingwei Xu;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Sep 2017, volume: 14, issue:5, pages: 494 - 506
Publisher: IEEE
 
» Manifold Embedding and Semantic Segmentation for Intraoperative Guidance With Hyperspectral Brain Imaging
Abstract:
Recent advances in hyperspectral imaging have made it a promising solution for intra-operative tissue characterization, with the advantages of being non-contact, non-ionizing, and non-invasive. Working with hyperspectral images in vivo, however, is not straightforward as the high dimensionality of the data makes real-time processing challenging. In this paper, a novel dimensionality reduction scheme and a new processing pipeline are introduced to obtain a detailed tumor classification map for intra-operative margin definition during brain surgery. However, existing approaches to dimensionality reduction based on manifold embedding can be time consuming and may not guarantee a consistent result, thus hindering final tissue classification. The proposed framework aims to overcome these problems through a process divided into two steps: dimensionality reduction based on an extension of the T-distributed stochastic neighbor approach is first performed and then a semantic segmentation technique is applied to the embedded results by using a Semantic Texton Forest for tissue classification. Detailed in vivo validation of the proposed method has been performed to demonstrate the potential clinical value of the system.
Autors: Daniele Ravì;Himar Fabelo;Gustavo Marrero Callic;Guang-Zhong Yang;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Sep 2017, volume: 36, issue:9, pages: 1845 - 1857
Publisher: IEEE
 
» Manipulation Over Phase Transformation in Iron Oxide Nanoparticles via Calcination Temperature and Their Effect on Magnetic and Dielectric Properties
Abstract:
Iron oxide nanoparticles (IONPs) have gained technological importance in many fields that broadly includes health, environment, and energy applications. Consequently, the synthesis of IONPs with different phases and morphologies possesses significant interest. Therefore, here we report the facile synthesis of IONPs through the hydrothermal method followed by calcination process at different temperatures (300 °C, 500 °C, and 700 °C) and studied the influence of various phases of IONPs on their magnetic and dielectric properties. The structural studies using X-ray diffraction confirmed that the as-prepared material possesses the Fe3O4 phase, and the increasing calcination temperatures leads to the phase transformation from maghemite (-Fe2O3 to hematite (-Fe2O3 phase. The morphological studies revealed that the as-prepared material possesses flaky morphology with a size around 20 nm, -Fe2O3 to have nanoparticles of sizes around 50 nm, and -Fe2O3 phase with mixed morphology of hexagonal and elongated shaped particles with size ranges from 60–140 nm. The optical properties of synthesized materials revealed that the band gap energy is found to be varied in between 2 and 2.7 eV depending upon the phase of IONPs. The hysteresis behavior of as-prepared and calcined IONPs at 300 °C and 500 °C indicated the soft-ferromagnetic properties of the phases. However, the IONPs prepared at 700° showed the weak-ferromagn- tic property due to the existence of mixed -Fe2O3 phase. All the calcined IONPs showed the soft-ferromagnetic properties with saturation magnetization () that varied in between 47.88 and 0.35 emu/g. The occurrence of the reduced ascribed to the phase transformation of the respective IONPs system. The dielectric studies of IONPs exhibited drastic variations with increasing frequency and with respect to their phase.
Autors: P. Bhavani;N. Ramamanohar Reddy;I. Venkata Subba Reddy;M. Sakar;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 5
Publisher: IEEE
 
» MAS Consensus and Delay Limits Under Delayed Output Feedback
Abstract:
In this technical note, we study the consensus problem for discrete-time multi-agent systems over an undirected, fixed network communication graph, focusing on the robustness of consensus with respect to communication delay. We assume that the agents' input is subject to a constant albeit possibly unknown time delay, and is generated by a distributed dynamic output feedback control protocol. Drawing upon concepts and techniques from robust control, notably those concerning gain margin optimization and analytic interpolation, we derive explicit, closed-form conditions for general linear agents to achieve consensus. Our results display an explicit dependence of the consensus condition on the delay value as well as on the agent's unstable poles and non-minimum phase zeros, showing that delayed communication between agents will generally hinder consensus and impose restrictions on the network topology. We also show that a lower bound on the maximal delay allowable for consensus can be computed by a simple line search method.
Autors: Tian Qi;Li Qiu;Jie Chen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4660 - 4666
Publisher: IEEE
 
» Massive Machine Type Communication With Data Aggregation and Resource Scheduling
Abstract:
To enable massive machine type communication (mMTC), data aggregation is a promising approach to reduce the congestion caused by a massive number of machine type devices (MTDs). In this paper, we consider a two-phase cellular-based mMTC network, where MTDs transmit to aggregators (i.e., aggregation phase) and the aggregated data is then relayed to base stations (i.e., relaying phase). Due to the limited resources, the aggregators not only aggregate data, but also schedule resources among MTDs. We consider two scheduling schemes: random resource scheduling (RRS) and channel-aware resource scheduling (CRS). By leveraging the stochastic geometry, we present a tractable analytical framework to investigate the signal-to-interference ratio (SIR) for each phase, thereby computing the MTD success probability, the average number of successful MTDs and probability of successful channel utilization, which are the key metrics characterizing the overall mMTC performance. Our numerical results show that, although the CRS outperforms the RRS in terms of SIR at the aggregation phase, the simpler RRS has almost the same performance as the CRS for most of the cases with regards to the overall mMTC performance. Furthermore, the provision of more resources at the aggregation phase is not always beneficial to the mMTC performance.
Autors: Jing Guo;Salman Durrani;Xiangyun Zhou;Halim Yanikomeroglu;
Appeared in: IEEE Transactions on Communications
Publication date: Sep 2017, volume: 65, issue:9, pages: 4012 - 4026
Publisher: IEEE
 
» Massive MIMO Performance With Imperfect Channel Reciprocity and Channel Estimation Error
Abstract:
Channel reciprocity in time-division duplexing (TDD) massive multiple-input multiple-output (MIMO) systems can be exploited to reduce the overhead required for the acquisition of channel state information (CSI). However, perfect reciprocity is unrealistic in practical systems due to random radio-frequency (RF) circuit mismatches in uplink and downlink channels. This can result in a significant degradation in the performance of linear precoding schemes, which are sensitive to the accuracy of the CSI. In this paper, we model and analyse the impact of RF mismatches on the performance of linear precoding in a TDD multi-user massive MIMO system, by taking the channel estimation error into considerations. We use the truncated Gaussian distribution to model the RF mismatch, and derive closed-form expressions of the output signal-to-interference-plus-noise ratio for maximum ratio transmission and zero forcing precoders. We further investigate the asymptotic performance of the derived expressions, to provide valuable insights into the practical system designs, including useful guidelines for the selection of the effective precoding schemes. Simulation results are presented to demonstrate the validity and accuracy of the proposed analytical results.
Autors: De Mi;Mehrdad Dianati;Lei Zhang;Sami Muhaidat;Rahim Tafazolli;
Appeared in: IEEE Transactions on Communications
Publication date: Sep 2017, volume: 65, issue:9, pages: 3734 - 3749
Publisher: IEEE
 
» Matching for Concurrent Harmonic Sensing in an ${M}$ -Phase Mixer-First Receiver
Abstract:
This brief proposes the use of passive mixer-first receiver topology to sense signals at higher LO harmonics. The advantages of such a receiver include sensing of multiple bands concurrently and reduced tuning range requirements in the frequency synthesizer. The single and joint harmonic matching performance of a zero-IF -phase mixer-first receiver is analyzed. It is shown that minimum possible return loss for joint matching occurs when the geometric mean of input impedances at the highest and lowest sensing bands equals the antenna impedance. The noise figure (NF) when sensing higher order LO harmonics is shown to result in only modest degradation, with the loss becoming even less with increasing number of LO phases. As an example, a 12-phase harmonicsensing mixer first receiver is simulated and its performance at first, third, and fifth harmonics is evaluated in terms of input matching and NF.
Autors: Esmail Babakrpur;Won Namgoong;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2017, volume: 64, issue:9, pages: 1017 - 1021
Publisher: IEEE
 
» Maximizing Acceptance in Rejection-Aware Spatial Crowdsourcing
Abstract:
With the rapid development of mobile networks and the widespread usage of mobile devices, spatial crowdsourcing, which refers to assigning location-based tasks to moving workers, has drawn increasing attention. One of the important issues in spatial crowdsourcing is task assignment, which allocates tasks to appropriate workers. However, existing works generally assume that no rejection would happen after the task assignment is completed by the server. Ignorance of such an operation can lead to low system throughput. Thus, in this paper, we take workers’ rejection into consideration and try to maximize workers’ acceptance in order to improve the system throughput. Specifically, we first formally define the problem of maximizing workers’ acceptance in rejection-aware spatial crowdsourcing. Unfortunately, the problem is NP-hard. We propose two exact solutions to obtain the optimal assignment, but they are not efficient enough and not scalable for large inputs. Then, we present four approximation approaches for improving the efficiency. Finally, we show the effectiveness of the proposed pruning strategy for the exact solutions and the superiority of the proposed Greedy algorithm over other approximation methods through extensive experiments.
Autors: Libin Zheng;Lei Chen;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 1943 - 1956
Publisher: IEEE
 
» Maximum Efficiency Point Tracking (MEPT) for Variable Speed Small Hydropower Plant With Neural Network Based Estimation of Turbine Discharge
Abstract:
The paper presents the control system of a small hydropower plant (SHP) working at variable speed operation (VSO). In general, VSO increases the turbine operating discharge and gives higher efficiency over a wide operating range. It is particularly advantageous under conditions different from the original design conditions. Changing of the hydrological conditions requires adjustments to the control system; therefore, the new maximum efficiency point tracking (MEPT) algorithm is proposed. The MEPT algorithm implemented in the load controller employs the gradient method. The water level governor based on the PI controller combined with the adaptive load controller is analyzed. The troublesome measurement of the turbine discharge is replaced by the neural-network-based estimator. The correlation analysis of the system parameters was performed by using principal component analysis. The proposed algorithm was implemented in the programmable logic controller and tested on a real low-head SHP of 150 kW power with two single-regulated propeller turbines.
Autors: Dariusz Borkowski;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1090 - 1098
Publisher: IEEE
 
» Maximum Power Point Tracking Strategy for a New Wind Power System and Its Design Details
Abstract:
This study presents two methods to improve the maximum power point tracking strategy for a new wind power system that consists of a planetary gear, two permanent magnet synchronous machines, and loads. The generator, the electric motor, and the wind turbine are connected to the sun gear, ring gear, and carrier of planetary gear, respectively. With the aid of an electric motor, the system can track the maximum power without the full-power converter for generator because of its special operating principle. Conventional optimum torque (COT) control method with a torque error feed forward branch is proposed to obtain faster response compared with COT control method. Moreover, considering that the actual power cannot reach the theoretical optimum point due to the loss torque of the system, the COT control with torque loss compensation is described. A method is also proposed to estimate loss torque. Finally, the theoretical analysis is verified by simulation and experiment results.
Autors: Zongze Cui;Liwei Song;Shupei Li;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1063 - 1071
Publisher: IEEE
 
» Measurements and Analyses of Electro-Exploding Products Generated by Semiconductor Bridge Igniters
Abstract:
In an effort to investigate the characteristics of electro-exploding products generated by Al/CuO-semiconductor bridge igniters, high-speed camera and spectrum diagnosis systems are employed in this paper. By using the high-speed camera system, the electro-exploding processes are recorded and the results indicate that electro-exploding processes include extrinsic conduction, intrinsic excitation, melting, vaporization, plasma discharging, and Al/CuO combustion. During this process, the spatial dimensions of plasma could reach to 8.7 mm in vertical direction under excitation energy of . Meanwhile, the Al/CuO films are ejected from ceramic housing by plasma shock wave, combust upon plasma and plume. According to the results from the spectrum diagnosis system, it is noted that the temperature maintains 4000–6500 K for .
Autors: Jun Wang;Yong Li;Bin Zhou;Xin Jia;Ruiqi Shen;Liu Wang;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2486 - 2491
Publisher: IEEE
 
» Mechanically Reconfigurable Conformal Array Antenna Fed by Radial Waveguide Divider With Tuning Screws
Abstract:
A conformal array antenna with a reconfigurable radiation pattern in the azimuth plane at Ku band is presented. An eight-faced prism has been set as 3-D antenna structure. The radiating element consists of a rectangular waveguide ended on a slotted cavity. A radial waveguide network (RWGN) fed by a symmetrically placed coaxial probe has been implemented to equally feed each radiating element obtaining an omnidirectional behavior in the azimuth plane. The insertion of several metallic tuning screws (TSs) provides a reconfiguration mechanism of the electric field distribution in the RWGN and modifies the conformal array antenna amplitude feeding. Eight different configurations generating directional radiation patterns can be tuned by means of the insertion of certain TSs. In addition, the symmetrical positioning of them allows performing a main beam scanning every 45° in the azimuth plane. Several prototypes have been manufactured and measured to experimentally validate the antenna performance. A total of 65 different radiation patterns have been experimentally obtained using the proposed TSs, which provides a simple, low-loss, and low-cost reconfigurability mechanism to the presented conformal array antenna.
Autors: P. Sanchez-Olivares;J. L. Masa-Campos;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4886 - 4890
Publisher: IEEE
 
» Media Transmission by Cooperation of Cellular Network and Broadcasting Network
Abstract:
Future media transmission as a consistent target is pursued by both next mobile communication system (5G) and advanced digital terrestrial television system. High data rate and flexibility are major considerations for future media transmission. Broadcasting network facilitates high-efficiency transmission of popular or live video in large area, and while, cellular network tends to provide personalized and localized services with a unicast/multicast model. The broadcast-like scheme emerges in 5G to resolve the high demand for bandwidth. However, it requires high deployment cost and imposes much interference on unicast/multicast services. In this paper, a cooperative structure of cellular network and broadcasting network using cloud radio access network (C-RAN) is proposed. The expenses of constructing hybrid network can be significantly cut down by applying the centralization and virtualization of C-RAN. Besides, technical approaches for 3GPP and ATSC cooperation in physical layer is detailed. Dedicated return channel (DRC) of broadcasting network is proposed to enable seamless interaction between broadcasters and few users in a remote area with high expense of cellular tower deployment. To loosen the real-time physical layer pipes period restriction of DRC system, three alternative periods are investigated to provide more flexibility to broadcasters.
Autors: Yanfeng Wang;Dazhi He;Lianghui Ding;Wenjun Zhang;Wei Li;Yiyan Wu;Ning Liu;Yao Wang;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Sep 2017, volume: 63, issue:3, pages: 571 - 576
Publisher: IEEE
 
» Medical Image Fusion and Denoising with Alternating Sequential Filter and Adaptive Fractional Order Total Variation
Abstract:
Medical image fusion aims at integrating information from multimodality medical images to obtain a more complete and accurate description of the same object, which provides an easy access for image-guided medical diagnostic and treatment. Unfortunately, medical images are often corrupted by noise in acquisition or transmission, and the noise signal is easily mistaken for a useful characterization of the image, making the fusion effect drop significantly. Thus, the existence of noise presents a great challenge for most of traditional image fusion methods. To address this problem, an effective variation model for multimodality medical image fusion and denoising is proposed. First, a multiscale alternating sequential filter is exploited to extract the useful characterizations (e.g., details and edges) from noisy input medical images. Then, a recursive filtering-based weight map is constructed to guide the fusion of main features of input images. Additionally, total variation (TV) constraint is developed by constructing an adaptive fractional order based on the local contrast of fused image, further effectively suppressing noise while avoiding the staircase effect of the TV. The experimental results indicate that the proposed method performs well with both noisy and normal medical images, outperforming conventional methods in terms of fusion quality and noise reduction.
Autors: Wenda Zhao;Huchuan Lu;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2017, volume: 66, issue:9, pages: 2283 - 2294
Publisher: IEEE
 
» Meetings calendar
Abstract:
Provides a listing of future meetings.
Autors: Davide Fabiani;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Sep 2017, volume: 33, issue:5, pages: 60 - 62
Publisher: IEEE
 
» Memory Performance of a Simple Pr0.7Ca0.3MnO3-Based Selectorless RRAM
Abstract:
Enhancement of nonlinearity (NL) in low-resistance state (LRS) currents of resistance random access memory (RRAM) devices is a key challenge for the selectorless RRAM array. The conventional approach is based on adding multiple dielectrics, e.g., tunnel layers to enable NL at the expense of stack simplicity. In this brief, we present a Pr0.7Ca0.3MnO3 (PCMO)-based selectorless RRAM device that exhibits high NL. The presented single oxide layer device (W/PCMO/Pt) enables selectorless RRAM without an extra tunnel barrier layer. The demonstrated device is forming free. It shows a low SET current density (104 A/cm2) and a high NL in LRS current for READ operation (105±5) and for SET operation (44±4) along with a large memory window (160±2) in dc cycling. Further, the device shows very low device-to-device variability along with excellent retention (ten years at 200 °C), good pulsed endurance (no degradation for >104 cycles), and a possible multilevel cell capability. A self-heating-based sharp current increase produces the NL to enable selectorless operation. Thus, a selectorless PCMO-based RRAM based on a novel mechanism is presented and benchmarked against the literature.
Autors: P. Kumbhare;I. Chakraborty;A. Khanna;U. Ganguly;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3967 - 3970
Publisher: IEEE
 
» Mesh Interpolated Krylov Recycling Method to Expedite 3-D Full-Wave MoM Solution for Design Variants
Abstract:
Today’s 3-D full-wave electromagnetic (EM) solvers follow the conventional model-mesh-solve workflow to analyze any EM structure. These solvers treat each model independently regardless of any similarity with a previously solved model and, therefore, sacrifice the possibility of accelerating a model solution from information harnessed from a prior solution of a similar model. This is a missed opportunity particularly in the solution of design variants, which involve multiple models with near-identical geometrical features. A Krylov recycling (KR) technique has been proposed in the past for the incremental solution of electrostatic problems. However, the technique is limited by the requirement of an unchanged mesh for the unmodified section of the model, which is difficult to achieve for a conformal mesh of a practical geometry. In this paper, a mesh-interpolated Krylov recycling (MIKR) technique is proposed to expedite the solution of 3-D full-wave surface-volume electric field integral equation-based system by reusing the Krylov subspace from the base design. The mesh interpolation mechanism is proposed to be able to handle mesh changes in the unmodified section of the model. The method is independent of the choice of fast solver compression methodology and the preconditioning strategy, and can be applied in unison with them. Numerical results demonstrate up to speedup in convergence over a cutting-edge preconditioned linear complexity fast solver methodology.
Autors: Gourav Chatterjee;Arkaprovo Das;Sreenivasulu Reddy Vedicherla;Dipanjan Gope;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3159 - 3171
Publisher: IEEE
 
» Method of Providing the High Cyclotron Harmonic Operation Selectivity in a Gyrotron With a Spatially Developed Operating Mode
Abstract:
An electrodynamic method for suppressing low-frequency oscillations at the fundamental cyclotron resonance in a gyrotron at a high cyclotron harmonic is proposed and theoretically investigated. According to simulations, the use of this method in the terahertz gyrotron at the second cyclotron harmonic operating at the spatially developed mode TE63,15 can provide a multiple excess of the starting currents of the parasitic modes over the starting current of the desired oscillations.
Autors: Ilya V. Bandurkin;Mikhail Yu Glyavin;Sergey V. Kuzikov;Petr B. Makhalov;Ivan V. Osharin;Andrey V. Savilov;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3893 - 3897
Publisher: IEEE
 
» Microfiber Coupling Structures for Magnetic Field Sensing With Enhanced Sensitivity
Abstract:
Two kinds of magnetic field sensors based on Sagnac loop and knot resonator configurations with microfiber coupling structures are proposed and investigated experimentally. The designed sensors are made from the microfiber coupler, whose coupling region is coated with magnetic fluid. The as-fabricated sensors have the same sensing/coupling region, but the achieved sensitivities are greatly different, which are 19.4 and 171.8 pm/Oe for the microfiber Sagnac loop and microfiber knot resonator structures, respectively. Comparing with the microfiber Sagnac loop and other similar microfiber knot resonator (or silicon microring) sensing structures, the sensitivity of the as-designed microfiber knot resonator sensing structure is enhanced significantly. The underlying mechanisms are expounded physically in terms of the microscopic formation of the coupling region and the essence of interference for the microfiber knot resonator structure. The designed structures could potentially lead to highly sensitive magnetic field sensors and other new-fashioned magneto-optical photonic devices.
Autors: Shengli Pu;Lianmin Mao;Tianjun Yao;Jinfeng Gu;Mahieddine Lahoubi;Xianglong Zeng;
Appeared in: IEEE Sensors Journal
Publication date: Sep 2017, volume: 17, issue:18, pages: 5857 - 5861
Publisher: IEEE
 
» Microplasma Traveling Wave Terahertz Amplifier
Abstract:
We describe a traveling wave terahertz (0.75–1.1 THz) amplifier that uses a meandering TE01 waveguide coupled to a plasma beam and discuss its design, microfabrication, and cold/hot tests. Motivations for using plasmas instead of electron beams are: 1) thermionic emission required in e-beam generation can be replaced with gas ionization, 2) electrostatic lenses and magnetic focusing structures can be eliminated or reduced in complexity since plasmas can be self-focusing, 3) larger acceleration fields can be used by taking advantage of plasmas’ space-charge electric fields of – V/cm, 4) the plasma pressure can be lowered to yield an electron beam in the limit when the devices’ critical dimensions are smaller than the electron mean-free path, and, hence, 5) higher power amplifications at higher efficiency can be achieved. Cold tests showed that a dielectric coating (50-nm Al2O3) of the gold-coated meandering silicon waveguide improved the maximum terahertz transmission (S21) from −20 to −15 dB. Hot tests showed 12-dB gain at a center frequency of ~0.9 THz over a 1-GHz bandwidth.
Autors: Massood Tabib-Azar;Olutosin Charles Fawole;Shashank S. Pandey;Carlos H. Mastrangelo;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3877 - 3884
Publisher: IEEE
 
» Microscopic and Macroscopic Spatio-Temporal Topic Models for Check-in Data
Abstract:
Twitter, together with other online social networks, such as Facebook, and Gowalla have begun to collect hundreds of millions of check-ins. Check-in data captures the spatial and temporal information of user movements and interests. To model and analyze the spatio-temporal aspect of check-in data and discover temporal topics and regions, we first propose a spatio-temporal topic model, i.e., Upstream Spatio-Temporal Topic Model (USTTM). USTTM can discover temporal topics and regions, i.e., a user’s choice of region and topic is affected by time in this model. We use continuous time to model check-in data, rather than discretized time, avoiding the loss of information through discretization. In addition, USTTM captures the property that user’s interests and activity space will change over time, and users have different region and topic distributions at different times in USTTM. However, both USTTM and other related models capture “microscopic patterns” within a single city, where users share POIs, and cannot discover “macroscopic” patterns in a global area, where users check-in to different POIs. Therefore, we also propose a macroscopic spatio-temporal topic model, MSTTM, employing words of tweets that are shared between cities to learn the topics of user interests. We perform an experimental evaluation on Twitter and Gowalla data sets from New York City and on a Twitter US data set. In our qualitative analysis, we perform experiments with USTTM to discover temporal topics, e.g., how topic “tourist destinations” changes over time, and to demonstrate that MSTTM indeed discovers macroscopic, generic topics. In our quantitative analysis, we evaluate the effectiveness of USTTM in terms of perplexity, accuracy of POI recommendation, and accuracy of user and time prediction. Our results show that the proposed USTTM achieves- better performance than the state-of-the-art models, confirming that it is more natural to model time as an upstream variable affecting the other variables. Finally, the performance of the macroscopic model MSTTM is evaluated on a Twitter US dataset, demonstrating a substantial improvement of POI recommendation accuracy compared to the microscopic models.
Autors: Yu Liu;Martin Ester;Yuqiu Qian;Bo Hu;David W. Cheung;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 1957 - 1970
Publisher: IEEE
 
» Microstrip Array Antenna With 2-D Steerable Focus in Near-Field Region
Abstract:
A microstrip planar array antenna is presented in this paper, which is designed to have near-field focused beams, and it is capable of steering its focus on the designed focal plane. The array is composed of eight series-fed linear arrays, which are able to scan the focus by frequency around 10 GHz in the H-plane, whereas, E-plane focus scan can be achieved by feeding the linear arrays with different phases. The proposed array can be used in near-field scan systems, e.g., microwave imaging system, with a faster scan rate than mechanically scanned antennas and a lower cost than array antennas with full phase control elements. Theoretical analysis is presented in this paper, and is verified by simulations and experiments.
Autors: Peng-Fa Li;Shi-Wei Qu;Shiwen Yang;Zai-Ping Nie;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4607 - 4617
Publisher: IEEE
 
» Microstructure and Magnetic Properties of Sm (CobalFe0.28Cu0.06Zr0.02)7.84 Magnet Prepared by Hydrogen Decrepitation and Mechanical Crushing
Abstract:
Two methods of pre-crushing power, hydrogen decrepitation (HD) and mechanical crushing (MC), were applied to prepare Sm (CobalFe0.28Cu0.06Zr0.02)7.84 magnets. Their microstructures and magnetic properties were investigated. Compared with a conventional MC method, the Sm2O3 content was decreased and the coercivity was enhanced from 8.67 to 24.03 kOe with an HD method. The larger grain size and less grain boundaries defects were obtained in HD magnets. In addition, the HD technology improved effective Sm content of magnets by decreasing oxidation of Sm. The effective Sm content played a significant role on microstructure and magnetic properties changes of the two kinds of magnets. In combinations with the changes of alloy composition and microstructures, the effect of HD technology on effective Sm content was discussed.
Autors: Y. P. Feng;M. Li;Z. Liu;L. Liu;C. X. Wang;R. J. Chen;Z. Q. Tian;Don Lee;A. R. Yan;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 4
Publisher: IEEE
 
» Microwave Applicator for Thermal Treatment of Bituminous Surfaces
Abstract:
A comprehensive study of a microwave applicator for thermal treatment of bituminous surface is presented in this paper. The applicator consists of a customized rectangular waveguide horn surrounded with a hexagonal lattice of cylindrical chokes preventing hazardous leakage of microwave radiation beyond an exposure area. Electromagnetic simulations based on a finite-difference time-domain method are applied in a design process and afterward, the prototype is manufactured with the aid of computerized numerical control machining. Eventually, the applicator is applied for experimental testing of microwave-assisted thermal treatment of the trial bituminous surface, which demonstrates that microwave energy may be a viable alternative to typical thermal bonding techniques used in road construction and maintenance processes if appropriate conditions are met.
Autors: Bartlomiej Salski;Marzena Olszewska-Placha;Tomasz Karpisz;Janusz Rudnicki;Wojciech Gwarek;Maciej Maliszewski;Adam Zofka;Jerzy Skulski;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3419 - 3427
Publisher: IEEE
 
» Microwave Monitoring of Single Cell Monocytes Subjected to Electroporation
Abstract:
This paper presents the monitoring of single cells subjected to electroporation using microwave dielectric spectroscopy. The experimental results showed first a clear distinction between two cell states: viable cells and affected ones by a chemical treatment (Saponin). It also pointed out a high correlation () with biological standard techniques in detecting the two types of electroporation: the reversible and irreversible ones. The developed microfluidic and microwave-based sensor exposes a decrease in the capacitive and conductive contrasts of the investigated single cells treated by irreversible electroporation indicating damages at the cellular level, while cells under reversible electroporation present a similar dielectric response to that of the nontreated cells. This result corresponds to results frequently employed in biological studies. More interestingly, a study of the kinetics of the cell’s damage induction over time, by electroporation, has been experimentally done, which makes microwave dielectric spectroscopy an attractive technique for cell’s electroporation researches.
Autors: Amar Tamra;David Dubuc;Marie-Pierre Rols;Katia Grenier;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3512 - 3518
Publisher: IEEE
 
» Microwave Sensors in Your Life [From the Guest Editors' Desk]
Abstract:
The articles in this special section addresses microwave sensor technology and discusses applications for its use. Radar sensors for military or automotive purposes and airport body scanners are examples that have gained wide interest, and the technology behind these has already been presented several times in the magazine. However, a significant number of microwave sensors used in our daily lives are not so well known to the average person because they are, for example, hidden behind walls or integrated into technical equipment.
Autors: Reinhard Knöchel;Christian Damm;W. Gregory Lyons;
Appeared in: IEEE Microwave Magazine
Publication date: Sep 2017, volume: 18, issue:6, pages: 24 - 25
Publisher: IEEE
 
» Microwave-Induced Thermoacoustic Communications
Abstract:
Wireless communications from an airborne device to an underwater receiver is challenging because the conductivity of water severely dampens the magnitude of electromagnetic waves in the spectrum commonly used for wireless applications. In this paper, microwave-induced thermoacoustic communications (TAC), a hybrid technique for wireless communications, is investigated and experimentally demonstrated to provide a potential solution to this deficiency. TAC is based on the thermoacoustic effect and directly converts electromagnetic energy in air into acoustic energy in water. Experimental demonstration of TAC is reported by successful wireless information transmission from a microwave antenna in air to an acoustic transducer in water. Bench-top TAC experiments are combined with an analytical model to study the influences of pivotal design parameters on the performance of TAC. The experiments and theoretical analysis suggest that TAC might lead to a new paradigm of air-to-underwater wireless communications.
Autors: Xiong Wang;Tao Qin;Yexian Qin;Russell S. Witte;Hao Xin;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3369 - 3378
Publisher: IEEE
 
» Millimeter Wave Communications for Future Mobile Networks
Abstract:
Millimeter wave (mmWave) communications have recently attracted large research interest, since the huge available bandwidth can potentially lead to the rates of multiple gigabit per second per user. Though mmWave can be readily used in stationary scenarios, such as indoor hotspots or backhaul, it is challenging to use mmWave in mobile networks, where the transmitting/receiving nodes may be moving, channels may have a complicated structure, and the coordination among multiple nodes is difficult. To fully exploit the high potential rates of mmWave in mobile networks, lots of technical problems must be addressed. This paper presents a comprehensive survey of mmWave communications for future mobile networks (5G and beyond). We first summarize the recent channel measurement campaigns and modeling results. Then, we discuss in detail recent progresses in multiple input multiple output transceiver design for mmWave communications. After that, we provide an overview of the solution for multiple access and backhauling, followed by the analysis of coverage and connectivity. Finally, the progresses in the standardization and deployment of mmWave for mobile networks are discussed.
Autors: Ming Xiao;Shahid Mumtaz;Yongming Huang;Linglong Dai;Yonghui Li;Michail Matthaiou;George K. Karagiannidis;Emil Björnson;Kai Yang;Chih-Lin I;Amitabha Ghosh;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 1909 - 1935
Publisher: IEEE
 
» Millimeter Wave Communications With OAM-SM Scheme for Future Mobile Networks
Abstract:
The orbital angular momentum (OAM) technique provides a new degree of freedom for information transmissions in millimeter wave communications. Considering the spatial distribution characteristics of OAM beams, a new OAM spatial modulation (OAM-SM) millimeter wave communication system is first proposed for future mobile networks. Furthermore, the capacity, average bit error probability, and energy efficiency of OAM-SM millimeter wave communication systems are analytically derived for performance analysis. Compared with the OAM-based multi-input multi-output (MIMO) millimeter wave communication systems, the maximum energy efficiency of OAM-SM millimeter wave communication systems is improved by 227.2%. Moreover, numerical results indicate that the proposed OAM-SM millimeter wave communication systems are more robust to path-loss attenuations than the conventional MIMO millimeter wave communication systems, which makes it suitable for long-range transmissions. Therefore, OAM-SM millimeter wave communication systems provide a great growth space for future mobile networks.
Autors: Xiaohu Ge;Ran Zi;Xusheng Xiong;Qiang Li;Liang Wang;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 2163 - 2177
Publisher: IEEE
 
» Millimeter-Wave Channel Measurements and Analysis for Statistical Spatial Channel Model in In-Building and Urban Environments at 28 GHz
Abstract:
The millimeter-wave (mm-wave) band will be a key component of fifth-generation (5G) wireless communication systems. This paper presents radio propagation measurements and analysis investigating the wideband directional channel characteristics of the mm-wave transmission for in-building and urban cellular communication systems in the 28-GHz band. Based on the measurements, we analyze and model the spatio-temporal channel characteristics such as multipath delay, angular statistics, and path loss. In particular we investigate the clustering of the multipath components, and investigate both the intra-cluster and inter-cluster distributions. Based on these investigations, we present a complete channel model suitable for system simulations in the in-building and urban environments.
Autors: Junghoon Ko;Yeon-Jea Cho;Sooyoung Hur;Taehwan Kim;Jeongho Park;Andreas F. Molisch;Katsuyuki Haneda;Michael Peter;Dong-Jo Park;Dong-Ho Cho;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 5853 - 5868
Publisher: IEEE
 
» Millimeter-Wave V2V Communications: Distributed Association and Beam Alignment
Abstract:
Recently, millimeter-wave (mmWave) bands have been postulated as a means to accommodate the foreseen extreme bandwidth demands in vehicular communications, which result from the dissemination of sensory data to nearby vehicles for enhanced environmental awareness and improved safety level. However, the literature is particularly scarce in regards to principled resource allocation schemes that deal with the challenging radio conditions posed by the high mobility of vehicular scenarios. In this paper, we propose a novel framework that blends together matching theory and swarm intelligence to dynamically and efficiently pair vehicles and optimize both transmission and reception beamwidths. This is done by jointly considering channel state information and queue state information when establishing vehicle-to-vehicle (V2V) links. To validate the proposed framework, simulation results are presented and discussed, where the throughput performance as well as the latency/reliability tradeoffs of the proposed approach are assessed and compared with several baseline approaches recently proposed in the literature. The results obtained in this paper show performance gains of 25% in reliability and delay for ultra-dense vehicular scenarios with 50% more active V2V links than the baselines. These results shed light on the operational limits and practical feasibility of mmWave bands, as a viable radio access solution for future high-rate V2V communications.
Autors: Cristina Perfecto;Javier Del Ser;Mehdi Bennis;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 2148 - 2162
Publisher: IEEE
 
» MIMO Terminal Performance Evaluation With a Novel Wireless Cable Method
Abstract:
Conventional conductive method, where antennas on the device under test (DUT) are disconnected from antenna ports and replaced with radio frequency (RF) coaxial cables, has been dominantly utilized in industry to evaluate multiple-input multiple-output capable terminals. However, direct RF cable connection introduces many practical problems and a radiated method to replace cable connection is highly desirable. Existing wireless cable method relies on the knowledge of a transfer matrix between the channel emulator (CE) output ports and DUT antenna ports, and also requires an anechoic chamber, which might be impractical and expensive. In this paper, a novel wireless cable method is proposed and experimentally validated. By recording the average power (i.e., reference signal received power in the long-term evolution) per DUT antenna port and selecting optimal complex weights at the CE output ports, a wireless cable connection can be achieved. The proposed method can be executed in a small RF shielded anechoic box and offers low system cost, high measurement reliability, and repeatability.
Autors: Wei Fan;Pekka Kyösti;Lassi Hentilä;Gert Frølund Pedersen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4803 - 4814
Publisher: IEEE
 
» Miniaturized Dipolar Patch Antenna With Narrow Meandered Slotline for UHF Tag
Abstract:
A compact dipolar patch, which has a dimension of , is designed for mounting on metal. The proposed antenna consists of a dipolar patch which is split by a narrow meandered slot into two halves. The narrow meandered slot is highly reactive and it is instrumental for scaling down the tag resonant frequency. Most importantly, the narrow slot does not affect the radiation characteristics of the patch resonator much, making the resonant frequency lower. In the design, the patches are stub-shorted to ground, where two inductive thin stubs are used for frequency adjustment. A simple equivalent circuit has been derived for studying the tag impedance characteristics. The proposed tag antenna can be read from beyond 4.5 m (at effective isotropic radiated power of 4 W) on metal. It can also be read from at least 2 m when used for dielectrics with in the range of 1–12.
Autors: Fwee-Leong Bong;Eng-Hock Lim;Fook-Loong Lo;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4435 - 4442
Publisher: IEEE
 
» Minimax Robust Hypothesis Testing
Abstract:
Minimax robust hypothesis testing is studied for the cases where the collected data samples are corrupted by outliers and are mismodeled due to modeling errors. For the former case, Huber’s clipped likelihood ratio test is introduced and analyzed. For the latter case, first, a robust hypothesis testing scheme based on the Kullback–Leibler divergence is designed. This approach generalizes a previous work by Levy. Second, Dabak and Johnson’s asymptotically robust test is introduced, and other possible designs based on -divergences are investigated. All proposed and analyzed robust tests are extended to fixed sample size and sequential probability ratio tests. Simulations are provided to exemplify and evaluate the theoretical derivations.
Autors: Gökhan Gül;Abdelhak M. Zoubir;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5572 - 5587
Publisher: IEEE
 
» Minimum Backups for Stream Processing With Recovery Latency Guarantees
Abstract:
The stream processing model continuously processes online data in an on-pass fashion that can be more vulnerable to failures than other big-data processing schemes. Existing fault-tolerant (FT) approaches have been presented to enhance the reliability of stream processing systems. However, the fundamental tradeoff between recovery latency and FT overhead is still unclear, so these scheme cannot provide recovery latency guarantees. This paper introduces the FT Configuration (FTC) problem and presents a solution for guaranteed recovery latency with minimum backups. A failure effect model is presented to describe the relationship between recovery latency and FTC (the amount and locations of backups). With this model, we design an algorithm to compute FTCs for different types of stream topologies according to recovery latency requirements. Extensive experiments are conducted to verify the correctness and effectiveness of our approach. We prove that our algorithm guarantees recovery latencies for all directed acyclic graph (DAG) stream topologies. For line(s) and tree topologies, our algorithm solves the FTC problem with a time complexity of . For a general DAG topology, a heuristic function is used to generate FTCs. This causes fewer than 10% more backups on average compared to the optimal solution with a time complexity of .
Autors: Hongliang Li;Jie Wu;Zhen Jiang;Xiang Li;Xiaohui Wei;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2017, volume: 66, issue:3, pages: 783 - 794
Publisher: IEEE
 
» Mining Competitors from Large Unstructured Datasets
Abstract:
In any competitive business, success is based on the ability to make an item more appealing to customers than the competition. A number of questions arise in the context of this task: how do we formalize and quantify the competitiveness between two items? Who are the main competitors of a given item? What are the features of an item that most affect its competitiveness? Despite the impact and relevance of this problem to many domains, only a limited amount of work has been devoted toward an effective solution. In this paper, we present a formal definition of the competitiveness between two items, based on the market segments that they can both cover. Our evaluation of competitiveness utilizes customer reviews, an abundant source of information that is available in a wide range of domains. We present efficient methods for evaluating competitiveness in large review datasets and address the natural problem of finding the top-k competitors of a given item. Finally, we evaluate the quality of our results and the scalability of our approach using multiple datasets from different domains.
Autors: George Valkanas;Theodoros Lappas;Dimitrios Gunopulos;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 1971 - 1984
Publisher: IEEE
 
» Mixed Channel Traffic Grooming for IP Over EON with SBPP-Based Cross-Layer Protection
Abstract:
We consider mixed channel traffic grooming in a shared backup path protected IP over elastic optical network (EON) and develop an auxiliary graph-based heuristic algorithm to share common optical channels between working and protection IP traffic flows. We compare integrated protection (i.e., cross-layer protection capacity sharing) with nonintegrated protection (i.e., overlay protection) to show how cross-layer sharing improves capacity utilization. Using simulations, network performance is evaluated in terms of the maximum number of frequency slots (FSs) used, the spare capacity redundancy, and the number of transponders required for a static traffic demand. For a dynamic traffic demand, the bandwidth blocking probability (BBP) is also obtained. It is found that the proposed mixed channel traffic grooming scheme can reduce both the BBP and the number of transponders required while improving the spectral efficiency compared to a system using dedicated channel traffic grooming. Integrated protection is also found to be more efficient than overlay protection under comparable conditions. We also observe that only a limited number of transponders per node and a limited number of FSs per transponder are sufficient to achieve good performance for an IP over EON with mixed channel traffic grooming and cross-layer spare capacity sharing.
Autors: Fengxian Tang;Weidong Shao;Lian Xiang;Sanjay K. Bose;Gangxiang Shen;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:18, pages: 3836 - 3848
Publisher: IEEE
 
» Mixed Nonprobabilistic Reliability-Based Optimization Method for Heat Transfer System With Fuzzy and Interval Parameters
Abstract:
By combining the nonprobabilistic reliability theory with optimization design approach, this paper proposes a mixed reliability-based optimization method for the heat transfer system design with both fuzzy and interval parameters in material property, external load, and boundary condition. Fuzzy variables are used to represent subjective uncertainties associated with expert opinions; whereas, interval variables are adopted to quantify objective uncertainties with limited information. Based on the level-cut strategy, the mixed uncertain problem is transformed into a pure interval problem first. Then, a modified reliability analysis method using an interval ranking strategy and integral operation is presented to precisely assess the system safety possibility. Subsequently, a mixed reliability-based optimization model with fuzzy and interval parameters is established, which is a nested optimization problem with huge computational cost. A subinterval perturbation method is eventually presented for temperature field prediction, which can replace the inner loop optimization and improve the computational efficiency. A transient heat conduction example about a three-layer thermal structure verifies the superiority of the proposed model and method for mixed reliability analysis and optimization in practical engineering.
Autors: Chong Wang;Zhiping Qiu;Menghui Xu;Yunlong Li;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2017, volume: 66, issue:3, pages: 630 - 640
Publisher: IEEE
 
» Mobile Energy Storage Scheduling and Operation in Active Distribution Systems
Abstract:
A mobile (transportable) energy storage system (MESS) can provide various services in distribution systems including load leveling, peak shaving, reactive power support, renewable energy integration, and transmission deferral. Unlike stationary energy storage units, an MESS can move between different buses by a truck to provide different local services within the distribution feeder. This paper proposes a day-ahead energy management system (EMS) for an MESS that aims to minimize the cost of the power imported from the grid. The MESS does not only shift renewable energy power to load peak-hours but also can provide localized reactive power support. Given the day-ahead predictions, the EMS decided the optimal MESS stations in the feeder and the operating power. Next, a particle swarm optimization-based algorithm is developed to tune the moving time of the MESS according to a transit delay model. The applicability of the proposed scheduling and operation algorithms is tested on a typical 41-bus radial feeder.
Autors: Hussein Hassan Abdeltawab;Yasser Abdel-Rady I. Mohamed;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 6828 - 6840
Publisher: IEEE
 
» Mobile Flywheel Energy Storage Systems: Determining Rolling Element Bearing Loads to Expand Possibilities
Abstract:
Efficient energy storage is the key to modern hybrid or zero emission vehicles and low carbon mobility in general. Compared to conventional storage technologies like batteries, flywheel energy storage systems (FESSs) offer various theoretical advantages, such as high cycle life, no capacity fade over time, temperature independence, easy determination of state of charge, and complete recyclability. However, the special operating conditions of FESSs-such as vacuum, high rotational speeds, and high gyroscopic reactions, etc.-make bearing design a complex and crucial endeavor. This article describes methods of determining loads for rolling element bearings in automotive FESSs. An overview of FESS technology is given, followed by the discussion of an analytic, numeric, and empiric approach, including a detailed comparison of the different methods. Furthermore, the concept of a test bench investigating flywheel behavior in a resilient mount is described, and its results regarding the design of an FESS-tovehicle mount are discussed in depth.
Autors: Armin Buchroithner;Andreas Brandstatter;Manes Recheis;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Sep 2017, volume: 12, issue:3, pages: 83 - 94
Publisher: IEEE
 
» Mobile-Edge Computing Versus Centralized Cloud Computing Over a Converged FiWi Access Network
Abstract:
The advent of Internet of Things and 5G applications renders the need for integration of both centralized cloud computing and emerging mobile-edge computing (MEC) with existing network infrastructures to enhance storage, processing, and caching capabilities in not only centralized but also distributed fashions for supporting both delay-tolerant and mission-critical applications. This paper investigates performance gains of centralized cloud and MEC enabled integrated fiber-wireless (FiWi) access networks. A novel unified resource management scheme incorporating both centralized cloud and MEC computation offloading activities into the underlying FiWi dynamic bandwidth allocation process is proposed. Both MEC and cloud traffic are scheduled outside the transmission slot of FiWi traffic by leveraging time division multiple access. An analytical framework is developed to model packet delay, response time efficiency, gain-offload overhead ratio, and communication-to-computation ratio for both cloud and broadband access traffic. In addition, given the importance of reliability in optical backhaul and MEC, this paper develops a probabilistic survivability analysis model to assess the impact of both fiber cuts and MEC server failures. The obtained results demonstrate the feasibility of implementing conventional cloud and MEC in FiWi access networks, without affecting network performance of broadband access traffic.
Autors: Bhaskar Prasad Rimal;Dung Pham Van;Martin Maier;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Sep 2017, volume: 14, issue:3, pages: 498 - 513
Publisher: IEEE
 
» Mobility-Aware and Congestion-Relieved Dedicated Path Planning for Group-Based Emergency Guiding Based on Internet of Things Technologies
Abstract:
This paper proposes a group-based framework with dedicated path planning for emergency guiding based on Internet of Things (IoT) technologies. The proposed framework can model the spatiotemporal mobility of indoor people to determine and relieve the congestion of corridors and exits. A dedicated path can be determined to provide the shortest evacuation time for each group of nearby people. The corridor and exit capacities, corridor lengths, clustering motion of a group, concurrent moving of different groups, and up-to-date distribution of group people are considered together to accurately estimate the evacuation time for each group. Based on the estimated evacuation time, evacuation load can be evenly distributed among corridors and exits to alleviate the congestion of all corridors and exits for minimizing total evacuation time. The performance of the proposed framework is evaluated by conducting mathematical analysis and computer simulations, which outperforms existing schemes and can achieve the shortest evacuation time for group-based emergency guiding. In addition, an Android-based prototype with indoor IoT localization technologies is implemented to verify the feasibility of our framework.
Autors: Lien-Wu Chen;Jhen-Jhou Chung;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Sep 2017, volume: 18, issue:9, pages: 2453 - 2466
Publisher: IEEE
 
» Model Mis-Specification Analyses of Weibull and Gamma Models Based on One-Shot Device Test Data
Abstract:
Model mis-specification is of great importance in reliability assessment. Different choices of probability models for fitting data may result in substantially different inferential results on some lifetime characteristics of interest. Gamma and Weibull models have been used extensively for modeling lifetime data. Hence, accelerated life models have been developed recently for one-shot device test data under both these models for making inference on mean lifetime as well as the reliability at use level. However, model mis-specification analyses between these two models have not been studied in this context. Here, we examine the effect of model mis-specification between gamma and Weibull models on the likelihood estimation and the inference on the mean lifetime and the reliability at some mission times based on one-shot device test data. Moreover, a distance-based test statistic and the Akaike information criterion as specification tests are studied for the purpose of model validation. A simulation study is carried out to evaluate the bias and coverage probabilities of confidence intervals under model mis-specification. The obtained results reveal that the effect of model mis-specification is negligible only when the sample size is small and when the accelerated and use levels are close, and that the use of specification test is quite important for an accurate reliability assessment.
Autors: Man Ho Ling;Narayanaswamy Balakrishnan;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2017, volume: 66, issue:3, pages: 641 - 650
Publisher: IEEE
 
» Model Uncertainty in Accelerated Degradation Testing Analysis
Abstract:
In accelerated degradation testing (ADT), test data from higher than normal stress conditions are used to find stochastic models of degradation, e.g., Wiener process, Gamma process, and inverse Gaussian process models. In general, the selection of the degradation model is made with reference to one specific product and no consideration is given to model uncertainty. In this paper, we address this issue and apply the Bayesian model averaging (BMA) method to constant stress ADT. For illustration, stress relaxation ADT data are analyzed. We also make a simulation study to compare the credibility intervals for single model and BMA. The results show that degradation model uncertainty has significant effects on the quantile lifetime at the use conditions, especially for extreme quantiles. The BMA can well capture this uncertainty and compute compromise credibility intervals with the highest coverage probability at each quantile.
Autors: Le Liu;Xiao-Yang Li;Enrico Zio;Rui Kang;Tong-Min Jiang;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2017, volume: 66, issue:3, pages: 603 - 615
Publisher: IEEE
 
» Model Validation of PWM DC–DC Converters
Abstract:
This paper presents hybrid automaton modeling, comparative model validation, and formal verification of stability through reachability analysis of pulse width modulation (PWM) dc–dc converters. Conformance degree provides a measure of closeness between the proposed hybrid automata models and experimental data. Nondeterminism due to variations in circuit parameters is modeled using interval matrices. In direct contrast to the unsound and computationally-intensive Monte Carlo simulation, reachability analysis is introduced to overapproximate the set of reachable states and ensure stable operation of PWM dc–dc converters. Using a 200 W experimental prototype of a buck converter, hybrid automata models of open-loop, and hysteresis-controlled converters are first validated against experimental data using their conformance degrees. Next, converter stability is formally verified through reachability analysis and informally validated using Monte Carlo simulations and experimental results.
Autors: Omar Ali Beg;Houssam Abbas;Taylor T. Johnson;Ali Davoudi;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7049 - 7059
Publisher: IEEE
 
» Modeling and Analysis of Lateral Propagation of Surface Acoustic Waves Including Coupling Between Different Waves
Abstract:
This paper discusses lateral propagation of surface acoustic waves (SAWs) in periodic grating structures when two types of SAWs exist simultaneously and are coupled. The thin plate model proposed by the authors is extended to include the coupling between two different SAW modes. First, lateral SAW propagation in an infinitely long periodic grating is modeled and discussed. Then, the model is applied to the Al-grating/42° YX-LiTaO3 (42-LT) substrate structure, and it is shown that the slowness curve shape changes from concave to convex with the Al grating thickness. The transverse responses are also analyzed on an infinitely long interdigital transducer on the structure, and good agreement is achieved between the present and the finite-element method analyses. Finally, SAW resonators are fabricated on the Cu grating/42-LT substrate structure, and it is experimentally verified that the slowness curve shape of the shear horizontal SAW changes with the Cu thickness.
Autors: Benfeng Zhang;Tao Han;Gongbin Tang;Qiaozhen Zhang;Tatsuya Omori;Ken-ya Hashimoto;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2017, volume: 64, issue:9, pages: 1354 - 1360
Publisher: IEEE
 
» Modeling and Characterization of Downwind Tower Shadow Effects Using a Wind Turbine Emulator
Abstract:
This paper presents the modeling and characterization of the tower shadow effects using a wind turbine emulator in a laboratory environment. In particular, the downwind wind turbines are considered here as their tower shadow effects are more significant compared to the upwind counterpart. Simulation and experimental results have shown that the wind speed deficit due to this nonideal effect is significant. In addition, the tower shadow effects occur typically two to three times per revolution, depending on the number of blades. The modeling of the tower shadow profiles for tubular and four-leg tower configurations is presented. Typically, these towers are used in small wind turbine applications. The tower shadow profiles are emulated experimentally using a wind turbine emulator with its characteristics being explained. The limitations of emulating the tower shadow effects using a wind turbine emulator are demonstrated through the frequency response test performed in this study. In this study, the wind turbine emulator is connected to an isolated grid which is formed by three single-phase inverters. Finally, this paper concludes with a sensitivity analysis of the power oscillations for different widths and magnitudes of the tower shadow profile.
Autors: Leong Kit Gan;Jonathan K. H. Shek;Markus A. Mueller;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7087 - 7097
Publisher: IEEE
 
» Modeling and Control of Stochastic Systems With Poorly Known Dynamics
Abstract:
This paper is concerned with controlling poorly known systems, for which only a simplified and rough model is available for control design. There are many systems that cannot be reasonably probed for the sake of identification, yet they are important for areas such as economy, populations, or medicine. The ideas are developed around an alternative way to account for the bare modeling in a stochastic-based setting, and to heighten the control features for such a modified model. The mathematical framework for the optimal control reveals important features such as the raising of a precautionary feedback policy of “keep the action unchanged” (inaction for short), on a certain state-space region. This feature is not seen in the robust approach, but has been pointed out and permeates part of the economics literature. The control problem relies on the viscosity solution for the Hamilton–Jacobi–Bellman equation, and the value of the problem is shown to be convex. When specialized to the quadratic problem with discounted cost, the exact solution inside the inaction region is given by a Lyapunov type of equation, and asymptotically, for large state values, by a Riccati-like equation. This scenario bridges to the stochastic stability analysis for the controlled model. The single control input is developed in full, part analytically, part numerically, for the scalar case, and an approximation is tested for the multidimensional case. The advantage of the precautionary policy is substantial in some situations.
Autors: João B. R. do Val;Rafael F. Souto;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4467 - 4482
Publisher: IEEE
 
» Modeling and Resonance Control of Modular Three-Level Shunt Active Power Filter
Abstract:
Compared with the conventional central shunt active power filter (SAPF), modular designed SAPF can track the harmonics more precisely and quickly with a compact and expandable structure, which makes it a better solution for harmonic mitigation. But there are very few paper discussed about the modeling and parallel resonance issues of modular SAPF parallel system. This paper provides a modeling of three-level SAPF, aiming to guide the modular design and research the parallel resonance control method. First, a simplified modular three-level SAPF modeling is proposed based on averaging impedance modeling and small signal linearization techniques. Then, the coupling issues between modules are researched, and a self-adaptive active damping method is proposed to suppress the system resonance. Based on the modeling results, an improved three-level SAPF module topology is proposed to construct the modular system. The theoretical analysis and experimental results verify that the module topology improvement together with the damping strategy can promise the compensating bandwidth, reliability, and fast, precise harmonics tracking ability.
Autors: Ling Feng;Yong Wang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7478 - 7486
Publisher: IEEE
 
» Modeling and Stability Analysis of DC-Link Voltage Control in Multi-VSCs With Integrated to Weak Grid
Abstract:
This paper contributes to giving physical insights into stability of DC-link voltage control in multi-wind turbines integrated to weak grid. Wind farm stability operation will suffer from integrating to weak AC grid, due to strong coupling between the wind turbines control and grid dynamics. Multi-VSCs model is presented for DC-link voltage control stability analysis with effect of coupling among VSCs and grid strength. Based on the model, self-impact components and interaction-impact components are presented to study interactions among VSCs. Impacts of VSCs interactions on stability of DC-link voltage control are studied by investigating self-impact and interaction-impact components variations with considering grid strength, operating point and control loop bandwidth. It is found that interactions between VSC1 and VSC2 become more serious with decline of grid strength, decaying stability of VSCs. Theoretical analysis is verified with simulation of two parallel wind turbines connected to weak grid.
Autors: Yunhui Huang;Dong Wang;Lei Shang;Guorong Zhu;Haiyan Tang;Yan Li;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1127 - 1138
Publisher: IEEE
 
» Modeling Electrode Place Discrimination in Cochlear Implant Stimulation
Abstract:
Objective: By modeling the cochlear implant (CI) electrode-to-nerve interface and quantifying electrode discriminability in the model, we address the questions of how many individual channels can be distinguished by CI recipients and the extent to which performance might be improved by inserting electrodes deeper into the cochlea. Method: We adapt an artificial neural network to model electrode discrimination as well as a commonly used psychophysical measure (four-interval forced-choice) in CI stimulation and predict how well the locations of the stimulating electrodes can be inferred from simulated auditory nerve spiking patterns. Results: We show that a longer electrode leads to better electrode place discrimination in our model. For a simulated four-interval forced-choice procedure, correct classification rates significantly reduce with decreasing distance between the test electrodes and the reference electrodes, and higher correct classification rates may be achieved by the basal electrodes than apical electrodes. Conclusion: Our results suggest that enhanced electrode discriminability results from a longer CI electrode array, and the locations where the errors occur along the electrode array are not only affected by the distance between electrodes but also the twirling angle between electrodes. Significance: Our models and simulations provide theoretical insights into several important clinically relevant problems that will inform future designs of CI electrode arrays and stimulation strategies.
Autors: Xiao Gao;David B. Grayden;Mark D. McDonnell;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Sep 2017, volume: 64, issue:9, pages: 2219 - 2229
Publisher: IEEE
 
» Modeling Information Diffusion over Social Networks for Temporal Dynamic Prediction
Abstract:
Modeling the process of information diffusion is a challenging problem. Although numerous attempts have been made in order to solve this problem, very few studies are actually able to simulate and predict temporal dynamics of the diffusion process. In this paper, we propose a novel information diffusion model, namely GT model, which treats the nodes of a network as intelligent and rational agents and then calculates their corresponding payoffs, given different choices to make strategic decisions. By introducing time-related payoffs based on the diffusion data, the proposed GT model can be used to predict whether or not the user's behaviors will occur in a specific time interval. The user’s payoff can be divided into two parts: social payoff from the user’s social contacts and preference payoff from the user’s idiosyncratic preference. We here exploit the global influence of the user and the social influence between any two users to accurately calculate the social payoff. In addition, we develop a new method of presenting social influence that can fully capture the temporal dynamics of social influence. Experimental results from two different datasets, Sina Weibo and Flickr demonstrate the rationality and effectiveness of the proposed prediction method with different evaluation metrics.
Autors: Dong Li;Shengping Zhang;Xin Sun;Huiyu Zhou;Sheng Li;Xuelong Li;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 1985 - 1997
Publisher: IEEE
 
» Modeling of DFIG-Based WTs for Small-Signal Stability Analysis in DVC Timescale in Power Electronized Power Systems
Abstract:
This paper presents a dynamic modeling methodology of a DFIG-based wind turbine (WT) for small-signal stability analysis in DC-link voltage control (DVC) timescale in power electronized power systems. The DVC timescale (around 100 ms) is determined by DVC, terminal voltage control, active power control, and phase-locked loop in DFIG WT. Motion equation concept is introduced and extended to describe DFIG WT external characteristics in the concerned timescale. The relation between the active/reactive power imbalances and phase/magnitude dynamics of defined synthetic internal voltage (inner potential) vector are developed. The model in DVC timescale is similar to synchronous generator rotor motion equation that is in electromechanical timescale (around 1 s) and familiar to power engineers. With the developed model, characteristics of equivalent inertia, damping and synchronizing coefficients of DFIG WT in DVC timescale can be understood, and the dynamic interactions among multiple DFIG WTs, as well as between DFIG WT and other grid-connected devices in DVC timescale can be fully interpreted. Comparisons of eigenvalues show that the proposed model can hold the main behaviors of concern. Applications on the stability analyses of DFIG WT interconnected with VSC-HVDC system and two-DFIG WT system are taken as examples to validate the feasibility of the proposed model.
Autors: Jiabing Hu;Hao Yuan;Xiaoming Yuan;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1151 - 1165
Publisher: IEEE
 
» Modeling of Grid-Connected VSCs for Power System Small-Signal Stability Analysis in DC-Link Voltage Control Timescale
Abstract:
With the increasing use of voltage source converters (VSCs) in power electronics dominated power systems, oscillation phenomena in DC-link voltage control (DVC) timescale (around 10 Hz) among multiple VSCs have occurred. Several studies have tried to analyze these oscillation problems, but all associated with the single VSC situation. To consider the dynamic interactions between VSCs in DVC timescale, especially in the weak grid condition, this paper presents a small-signal model to understand VSC external characteristics based on motion equation concept also featured in synchronous generator (SG). Comparisons of time-domain simulation responses and eigenvalues show that the proposed model can hold the main behaviors of concern. The form of the model is very similar to the rotor motion equation in SG, with which power engineers have been very familiar. In addition, by establishing the relationship between the unbalanced powers and state variables of internal voltage (viz., VSC output voltage), the modeling idea introduced in this paper can be applied to other power electronic devices.
Autors: Hao Yuan;Xiaoming Yuan;Jiabing Hu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3981 - 3991
Publisher: IEEE
 
» Modeling of Magnetoelectric Effects in Magnetostrictive/Piezoelectric Laminated Composites Using the Energy Method
Abstract:
The current models of the resonant magnetoelectric (ME) effect are based on Newton’s equation of motion and some given conditions which are various in published papers. Even some results are in conflict with Gauss’s law in magnetics. This paper provides the energy method to model ME effects. The energy method is based on linear constitutive equations and the principle of minimum energy. By constructing and solving the constraint problem of the variational principle, more reasonable conditions are deduced for simplifying Newton’s motion equation. The induced additional fields of externally applied fields are considered during the process of deducing by Gauss’s law for electricity or magnetism. The coefficients of direct/converse ME effects are obtained and compared with the models in the previous papers. The proposed model avoids conflict with Gauss’s law and provides another insight into understanding the resonant and static ME effects.
Autors: Jianzhong Li;Yumei Wen;Ping Li;Jin Yang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 6
Publisher: IEEE
 
» Modified Trust Region Algorithm for Dispersion Optimization of Photonic Crystal Fibers
Abstract:
In this paper, a modified derivative-free surrogate-based trust region optimization algorithm is proposed for optimizing the dispersion properties of photonic crystal fibers (PCFs) for the first time to the best of our knowledge. The modal analysis of the PCF is made using the full vectorial finite difference method with perfect matched layer boundary condition. The numerical results are compared with another trust region algorithm and other metaheuristic techniques to show the strength of the reported technique. Further, the modified algorithm is also used to achieve a nearly ultra-flattened zero dispersion over a wide range of wavelengths from 1.45 μm to 1.6 μm using an index guiding soft glass PCF selectively infiltrated with a nematic liquid crystal. In order to show the strength of the reported algorithm, a highly negative flat dispersion compensation PCF is also designed over wavelength range from 1.4 μm to 1.6 μm. Such a design has a negative dispersion of -155 ± 0.5 ps/Km·nm over the studied wavelength range. The trust region algorithms show a strong potential as an efficient tool for the design and optimization of different photonic devices. Further, these algorithms can be used as powerful techniques for solving the inverse problems.
Autors: Mohamed Farhat O. Hameed;Abdel-karim S. O. Hassan;Ahmed E. Elqenawy;Salah S. A. Obayya;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3810 - 3818
Publisher: IEEE
 
» MODIS Aqua Optical Throughput Degradation Impact on Relative Spectral Response and Calibration of Ocean Color Products
Abstract:
Since Moderate Resolution Imaging Spectroradiometer Aqua’s launch in 2002, the radiometric system gains of the reflective solar bands have been degrading, indicating changes in the system’s optical throughput. To estimate the optical throughput degradation, the electronic gain changes were estimated and removed from the measured system gain. The derived optical throughput degradation shows a rate that is much faster in the shorter wavelengths than the longer wavelengths. The wavelength-dependent optical throughput degradation modulated the relative spectral response (RSR) of the bands. In addition, the optical degradation is also scan angle-dependent due to large changes in response versus the scan angle over time. We estimated the modulated RSR as a function of time and scan angles and its impacts on sensor radiometric calibration for the ocean science. Our results show that the calibration bias could be up to 1.8% for band 8 (412 nm) due to its larger out-of-band response. For the other ocean bands, the calibration biases are much smaller with magnitudes at least one order smaller.
Autors: Shihyan Lee;Gerhard Meister;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Sep 2017, volume: 55, issue:9, pages: 5214 - 5219
Publisher: IEEE
 
» Modulation Technique for Single-Phase Transformerless Photovoltaic Inverters With Reactive Power Capability
Abstract:
This paper underpins the principles for generating reactive power in single-phase transformerless photovoltaic (PV) inverters. Two mainstream and widely adopted PV inverters are explored, i.e., H5 and HERIC. With conventional modulation techniques, reactive power cannot be realized in H5 and HERIC due to the absence of freewheeling path in negative power region. Based on the study, modulation techniques are proposed to provide bidirectional current path during freewheeling period. With proposed modulation technique, reactive power control is achieved in H5 and HERIC inverters, without any modification on the converter structures. The performances of the proposed modulation techniques are studied via MATLAB simulation and further validated with experimental results.
Autors: Tan Kheng Suan Freddy;June-Hee Lee;Hyun-Cheol Moon;Kyo-Beum Lee;Nasrudin Abd Rahim;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 6989 - 6999
Publisher: IEEE
 
» Monitoring and Mitigation of Ionospheric Anomalies for GNSS-Based Safety Critical Systems: A review of up-to-date signal processing techniques
Abstract:
The ionosphere has been the most challenging source of error to mitigate within the community of global navigation satellite system (GNSS)-based safety-critical systems. Users of those systems should be assured that the difference between an unknown true position and a system-derived position estimate is bounded with an extremely high degree of confidence. One of the major concerns for meeting this requirement, known as integrity, is ionosphere-induced error or discontinuity of GNSS signals significant enough to threaten the safety of users. The potentially hazardous ionospheric anomalies of interest in this article are ionospheric spatial decorrelation and ionospheric scintillation under disturbed conditions. As the demand of safety-critical navigation applications increases with the rapid growth of the autonomous vehicle sector, ionospheric monitoring and mitigation techniques become more important to support such systems.
Autors: Jiyun Lee;Y.T. Jade Morton;Jinsil Lee;Hee-Seung Moon;Jiwon Seo;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 96 - 110
Publisher: IEEE
 
» Monitoring of Corrosion-Induced Degradation in Prestressed Concrete Structure Using Embedded Piezoceramic-Based Transducers
Abstract:
Corrosion-induced cracking in prestressed concrete elements has been one of the most dominant factors that can cause the deterioration of concrete structures. Since most of the corrosion-induced cracks in their early age are invisible, qualitative and quantitative estimation of the corrosion-induced damage is not applicable before surface cracks can be observed. In this paper, the authors present a stress wave-based active sensing approach using embedded piezoceramic-based transducers to monitor the corrosion-induced degradation in prestressed concrete structures. Two concrete beams each mounted with two corrosion tanks were fabricated; one beam was embedded with a pretensioned strand and the other one with an untensioned strand. Two different corrosion rates were also considered in the accelerated corrosion process to verify the reliability and sensitivity of the approach. The characteristics of the propagating stress wave between a pair of embedded piezoceramic-based transducers were highly influenced by the concrete condition on the wave path. The received signals were analyzed in time domain, frequency domain, and through the wavelet packet-based energy index. Experimental results show that the received signal energy slightly increases in the initial corrosion stage due to the internal expansion pressure caused by the corrosion products. Subsequently, with the occurrence and the development of the corrosion-induced cracks, the energy of the received signal decreases as the corrosion damage develops. When the corrosion process almost completes, the energy of the received signal becomes stable. The experimental results show that the developed piezoceramic-based active sensing approach can monitor the corrosion-induced degradation and estimate the progress of the corrosion process in real time, and has potentials to provide early warning of the initial corrosion occurrence for prestressed concrete structures.
Autors: Tianyong Jiang;Qingzhao Kong;Zhong Peng;Lei Wang;Lizhao Dai;Qian Feng;Linsheng Huo;Gangbing Song;
Appeared in: IEEE Sensors Journal
Publication date: Sep 2017, volume: 17, issue:18, pages: 5823 - 5830
Publisher: IEEE
 
» Monolithic Add–Drop Multiplexers in Fused Silica Fabricated by Femtosecond Laser Direct Writing
Abstract:
The fabrication of optical add-drop multiplexers in fused silica is demonstrated, for the first time to our knowledge, using the femtosecond laser direct writing technique. To achieve this, a Mach-Zehnder interferometer configuration was used for the signal routing by the implementation of 3-dB directional couplers, along with Bragg grating waveguides for wavelength selectivity. The fabrication of all individual devices required was optimized. The behavior of the fabricated add-drop multiplexer was characterized at around 1550 nm, where a 3-dB bandwidth of 0.19 ± 0.01 nm was obtained along with an intrachannel and adjacent interchannel crosstalk of -30 and -20 dB at Δλ = ± 0.75 nm, respectively. This study shows that such complex devices can be manufactured by femtosecond laser direct writing, with future improvements being discussed.
Autors: Vítor A. Amorim;João M. Maia;D. Alexandre;P. V. S. Marques;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3615 - 3621
Publisher: IEEE
 
» Monolithic Three-Dimensional 65-nm CMOS-Nanoelectromechanical Reconfigurable Logic for Sub-1.2-V Operation
Abstract:
Monolithic three-dimensional (M3D) CMOS-nanoelectromechanical (CMOS-NEM) reconfigurable logic (RL) circuits are experimentally demonstrated. This is the first experimental demonstration of 65-nm M3D CMOS-NEM RL circuits satisfying the 1.2-V supply voltage () requirement of the 65-nm technology node. The fabrication process is identical to the conventional 65-nm CMOS baseline process, in which copper NEM memory switches are formed by a dual damascene process.
Autors: Hyug Su Kwon;Seung Kyu Kim;Woo Young Choi;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1317 - 1320
Publisher: IEEE
 
» Motivating Network Deployment: Vehicular Communications
Abstract:
Many new and promising vehicular communications applications are currently being developed. However, sufficient network resources to support these applications, in terms of equipped vehicles, base stations, and other infrastructure, are simply not yet available and are progressing slowly. In this article, we examine the strengths and uses of dedicated short-range communications (DSRC) and cellular vehicular networks. We then explore strategies, beyond government mandates and subsidies, to encourage vehicular network deployment.
Autors: Tom Glenn McGiffen;Sven Beiker;Arogyaswami Paulraj;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Sep 2017, volume: 12, issue:3, pages: 22 - 33
Publisher: IEEE
 
» Movable Noncontact RF Current Measurement on a PCB Trace
Abstract:
This paper develops a movable noncontact probing method of a radio frequency current on a printed trace based on the electromagnetic induction. The current measurement method is validated by comparing a series of reconstructed periodic and pulse currents with those as known input signals on a microstrip line. According to our measurement, the transfer impedance from the current under measurement to the probe has a linear frequency range from 10 MHz to 2.2 GHz. The reconstruction measurement can be achieved even for a random periodic noise with a duration of 1 ns and a single pulse with a rise time of 2 ns. Owing to the flexible relocation of the probe, the measurement accuracy due to the errors of spatial displacement and the probe placement angle is investigated in detail. It is shown that the dynamic parameters of reconstructed current, such as fall time and rise time, are insensitive to the spatial errors, and instead the amplitudes of both periodic and pulse currents are highly sensitive, especially to a horizontal displacement.
Autors: Haimi Qiu;Wenxiao Fang;Yunfei En;Yun Huang;Yuan Liu;Ping Lai;Yiqiang Chen;Chunlei Shi;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2017, volume: 66, issue:9, pages: 2464 - 2473
Publisher: IEEE
 
» MoveIt!: Autonomous Underwater Free-Floating Manipulation
Abstract:
Today, autonomous underwater vehicles (AUVs) are mostly used for survey missions, but many existing applications require manipulation capabilities, such as the maintenance of permanent observatories, submerged oil wells, cabled sensor networks, and pipes; the deployment and recovery of benthic stations; or the search and recovery of black boxes. Currently, these tasks require the use of work-class remotely operated vehicles (ROVs) deployed from vessels equipped with dynamic positioning, leaving such solutions expensive to adopt. To face these challenges during the last 25 years, scientists have researched the idea of increasing the autonomy of underwater intervention systems.
Autors: Dina Youakim;Pere Ridao;Narcis Palomeras;Francesco Spadafora;David Ribas;Maurizio Muzzupappa;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2017, volume: 24, issue:3, pages: 41 - 51
Publisher: IEEE
 
» Multi-Instance Classification by Max-Margin Training of Cardinality-Based Markov Networks
Abstract:
We propose a probabilistic graphical framework for multi-instance learning (MIL) based on Markov networks. This framework can deal with different levels of labeling ambiguity (i.e., the portion of positive instances in a bag) in weakly supervised data by parameterizing cardinality potential functions. Consequently, it can be used to encode different cardinality-based multi-instance assumptions, ranging from the standard MIL assumption to more general assumptions. In addition, this framework can be efficiently used for both binary and multiclass classification. To this end, an efficient inference algorithm and a discriminative latent max-margin learning algorithm are introduced to train and test the proposed multi-instance Markov network models. We evaluate the performance of the proposed framework on binary and multi-class MIL benchmark datasets as well as two challenging computer vision tasks: cyclist helmet recognition and human group activity recognition. Experimental results verify that encoding the degree of ambiguity in data can improve classification performance.
Autors: Hossein Hajimirsadeghi;Greg Mori;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Sep 2017, volume: 39, issue:9, pages: 1839 - 1852
Publisher: IEEE
 
» Multi-Layer Precoding: A Potential Solution for Full-Dimensional Massive MIMO Systems
Abstract:
Massive MIMO systems achieve high sum spectral efficiency by simultaneously serving large numbers of users. In time division duplexing systems, however, the reuse of uplink training pilots among cells results in channel estimation errors, which causes downlink inter-cell interference. Handling this interference is challenging due to the large channel dimensionality and the high complexity associated with implementing large precoding/combining matrices. In this paper, we propose multi-layer precoding to enable efficient and low-complexity operation in full-dimensional massive MIMO, where a large number of antennas are used in two dimensions. In multi-layer precoding, the precoding matrix of each base station is written as a product of a number of precoding matrices. Multi-layer precoding: 1) leverages the directional characteristics of large-scale MIMO channels to manage inter-cell interference with low channel knowledge requirements and 2) allows for an efficient implementation using hybrid analog/digital architectures. We present and analyze a specific multi-layer precoding design for full-dimensional massive MIMO systems. The asymptotic optimality of the proposed design is then proved for some special yet important channels. Numerical simulations verify the analytical results and illustrate the potential gains of multi-layer precoding compared with other multi-cell precoding solutions.
Autors: Ahmed Alkhateeb;Geert Leus;Robert W. Heath;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 5810 - 5824
Publisher: IEEE
 
» Multi-Purpose Fully Differential 61- and 122-GHz Radar Transceivers for Scalable MIMO Sensor Platforms
Abstract:
This paper describes a multi-purpose radar system suitable for applications with different requirements on dynamic range, resolution, and miniaturization degree. It utilizes a scalable sensor platform that includes a wideband 30.5-GHz voltage-controlled oscillator (VCO) as well as 61- and 122-GHz transceivers (TRXs) in a silicon-germanium BiCMOS technology. The proposed architecture enables the cascading of multiple TRXs and allows the implementation of MIMO radar systems in two different frequency bands by using a single VCO. The higher transmit output power of 11.5 dBm as well as receive gain of 24 dB make the 61-GHz TRX suitable for applications requiring a high dynamic range. The lower wavelength allows the integration of on-chip antennas in the 122-GHz TRX and enables, thus, a high miniaturization degree. The higher LO scaling factor makes the 122-GHz TRX also more attractive for high-resolution applications. A sweep bandwidth of 2.5 GHz generated by the VCO is scaled up to 10 GHz and results in a range resolution of 3 cm. The proposed TRXs are equipped with binary phase shift keying modulators as well as an I/Q receiver and can be utilized to build a flexible software-defined radar platform for range and distant-selective vibration sensors utilizing frequency-modulated continuous wave as well as pseudo-random noise radar techniques.
Autors: Herman Jalli Ng;Maciej Kucharski;Wael Ahmad;Dietmar Kissinger;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2017, volume: 52, issue:9, pages: 2242 - 2255
Publisher: IEEE
 
» Multi-Resolution Codebook and Adaptive Beamforming Sequence Design for Millimeter Wave Beam Alignment
Abstract:
Millimeter wave (mm-wave) communication is expected to be widely deployed in fifth generation (5G) wireless networks due to the substantial bandwidth available for licensed and unlicensed use at mm-wave frequencies. To overcome the higher path loss observed at mm-wave bands, most prior work focused on the design of directional beamforming using analog and/or hybrid beamforming techniques in large-scale multiple-input multiple-output systems. Obtaining potential gains from highly directional beamforming in practical systems hinges on sufficient levels of channel estimation accuracy, where the problem of channel estimation becomes more challenging due to the substantial training overhead needed to sound all directions using a high-resolution narrow beam. In this paper, we consider the design of multi-resolution beamforming sequences to enable the system to quickly search out the dominant channel direction for single-path channels. The resulting design generates a multilevel beamforming sequence that strikes a balance between minimizing the training overhead and maximizing beamforming gain, where a subset of multilevel beamforming vectors is chosen adaptively to maximize the average data rate within a constrained time. We propose an efficient method to design a hierarchical multi-resolution codebook utilizing a Butler matrix, i.e., a generalized discrete Fourier transform matrix. Numerical results show the effectiveness of the proposed algorithm.
Autors: Song Noh;Michael D. Zoltowski;David J. Love;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2017, volume: 16, issue:9, pages: 5689 - 5701
Publisher: IEEE
 
» Multi-Task Rank Learning for Image Quality Assessment
Abstract:
In practice, images are distorted by more than one distortion. For image quality assessment (IQA), existing machine learning (ML)-based methods generally establish a unified model for all the distortion types, or each model is trained independently for each distortion type, which is therefore distortion aware. In distortion-aware methods, the common features among different distortions are not exploited. In addition, there are fewer training samples for each model training task, which may result in overfitting. To address these problems, we propose a multi-task learning framework to train multiple IQA models together, where each model is for each distortion type; however, all the training samples are associated with each model training task. Thus, the common features among different distortion types and the said underlying relatedness among all the learning tasks are exploited, which would benefit the generalization ability of trained models and prevent overfitting possibly. In addition, pairwise image quality ranking instead of image quality rating is optimized in our learning task, which is fundamentally departed from traditional ML-based IQA methods toward better performance. The experimental results confirm that the proposed multi-task rank-learning-based IQA metric is prominent against all state-of-the-art nonreference IQA approaches.
Autors: Long Xu;Jia Li;Weisi Lin;Yongbing Zhang;Lin Ma;Yuming Fang;Yihua Yan;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Sep 2017, volume: 27, issue:9, pages: 1833 - 1843
Publisher: IEEE
 
» Multi-View Surveillance Video Summarization via Joint Embedding and Sparse Optimization
Abstract:
Most traditional video summarization methods are designed to generate effective summaries for single-view videos, and thus, they cannot fully exploit the complicated intra- and inter-view correlations in summarizing multi-view videos in a camera network. In this paper, with the aim of summarizing multi-view videos, we introduce a novel unsupervised framework via joint embedding and sparse representative selection. The objective function is twofold. The first is to capture the multi-view correlations via an embedding, which helps in extracting a diverse set of representatives. The second is to use a -norm to model the sparsity while selecting representative shots for the summary. We propose to jointly optimize both of the objectives, such that embedding can not only characterize the correlations, but also indicate the requirements of sparse representative selection. We present an efficient alternating algorithm based on half-quadratic minimization to solve the proposed non-smooth and non-convex objective with convergence analysis. A key advantage of the proposed approach with respect to the state-of-the-art is that it can summarize multi-view videos without assuming any prior correspondences/alignment between them, e.g., uncalibrated camera networks. Rigorous experiments on several multi-view datasets demonstrate that our approach clearly outperforms the state-of-the-art methods.
Autors: Rameswar Panda;Amit K. Roy-Chowdhury;
Appeared in: IEEE Transactions on Multimedia
Publication date: Sep 2017, volume: 19, issue:9, pages: 2010 - 2021
Publisher: IEEE
 
» Multi-View Unsupervised Feature Selection with Adaptive Similarity and View Weight
Abstract:
With the advent of multi-view data, multi-view learning has become an important research direction in both machine learning and data mining. Considering the difficulty of obtaining labeled data in many real applications, we focus on the multi-view unsupervised feature selection problem. Traditional approaches all characterize the similarity by fixed and pre-defined graph Laplacian in each view separately and ignore the underlying common structures across different views. In this paper, we propose an algorithm named Multi-view Unsupervised Feature Selection with Adaptive Similarity and View Weight (ASVW) to overcome the above mentioned problems. Specifically, by leveraging the learning mechanism to characterize the common structures adaptively, we formulate the objective function by a common graph Laplacian across different views, together with the sparse -norm constraint designed for feature selection. We develop an efficient algorithm to address the non-smooth minimization problem and prove that the algorithm will converge. To validate the effectiveness of ASVW, comparisons are made with some benchmark methods on real-world datasets. We also evaluate our method in the real sports action recognition task. The experimental results demonstrate the effectiveness of our proposed algorithm.
Autors: Chenping Hou;Feiping Nie;Hong Tao;Dongyun Yi;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Sep 2017, volume: 29, issue:9, pages: 1998 - 2011
Publisher: IEEE
 
» Multibroker-Based Service Provisioning in Multidomain SD-EONs: Why and How Should the Brokers Cooperate With Each Other?
Abstract:
It is known that software-defined elastic optical networks (SD-EONs) facilitate optical networking that provides better network programmability, more powerful manageability, and more flexible service provisioning capability. Moreover, the hierarchical architecture of multibroker-based multidomain SD-EONs cannot only improve the network scalability but also maintain the autonomy of each administrative domain. In this paper, we study why and how the brokers should cooperate with each other to provision interdomain lightpaths in multibroker-based multidomain SD-EONs. We first formulate a cooperative market in which the brokers negotiate about their market shares (i.e., the opportunities to provision interdomain lightpaths) and seek for a mutual agreement with Nash bargaining [1]. Then, we design a mathematical model to describe the market as well as the brokers' behaviors in it. An effective algorithm is derived from the model to solve the Nash bargaining problem for allocating lightpath requests among the brokers. The proposed algorithm also addresses the resource collision during request provisioning and can achieve collision-free request allocation. Extensive simulations verify the effectiveness of our proposal.
Autors: Lu Sun;Xiaoliang Chen;Zuqing Zhu;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3722 - 3733
Publisher: IEEE
 
» Multifrequency Experimental Analysis (10 to 77 GHz) on the Asphalt Reflectivity and RCS of FOD Targets
Abstract:
In this letter, a multifrequency experimental analysis is conducted for the estimation of the asphalt reflectivity and for the measurement of the radar cross section of some typical foreign object debris (FOD). The analysis is made with experimental data with a frequency between 10 and 77 GHz, acquired with a vector network analyzer and with-ingegneria dei sistemi 77-GHz radar prototype for FOD Detection. Experimental data acquired in a real operative scenario (runway of Taranto/Grottaglie airport) is also presented. The results show the possibility to detect an FOD target on an airport runway.
Autors: Gaetano Mollo;Rosario Di Napoli;Giuseppe Naviglio;Carmine Di Chiara;Egidio Capasso;Giovanni Alli;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1441 - 1443
Publisher: IEEE
 
» Multifrequency Transformer With Arbitrary Frequency and Real Impedance Transform Ratio
Abstract:
In this letter, the modified small reflection theory is further extended to the design of a multifrequency transformer with an arbitrary frequency and real impedance transform ratio, by mapping small reflection coefficients between - and -section transformers. Due to the introduced mapping, the dominated equation of the -section transformer is reduced to that of the -section transformer without introducing an additional matching frequency among the desired frequency ratio range. For verification, a penta-frequency transformer is implemented and measured. The measured results agree closely with the calculated and simulated results.
Autors: Liang Liu;Ronghong Jin;Xianling Liang;Haijun Fan;Wenzhi Wang;Junping Geng;Fuwen Liu;Yifeng Chen;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2017, volume: 27, issue:9, pages: 785 - 787
Publisher: IEEE
 
» Multimode Adaptable Microwave Radar Sensor Based on Leaky-Wave Antennas
Abstract:
New research and recent developments in active defense systems represent a promising way to protect military vehicles by detecting and subsequently eliminating threatening missiles with appropriate active counter-measures. Operating these defense systems requires a number of sensors, usually microwave, which must, above all, identify and track the target while generating signals to determine the correct counter-measure reaction. This paper shows that such multifunction and multimode sensors can be designed and implemented using leaky-wave antennas (LWAs). Connected radar circuits often employ a wideband modulation, so an analysis of the influence of the LWAs used on such a modulation is also included. A multimode adaptable pseudonoise radar equipped with LWAs was tested using bullets and live, armed cumulative missiles. The results confirm the functionality of the solutions presented.
Autors: Premysl Hudec;Petr Panek;Vojtech Jenik;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3464 - 3473
Publisher: IEEE
 
» Multipartite Entangled States, Symmetric Matrices, and Error-Correcting Codes
Abstract:
A pure quantum state is called -uniform if all its reductions to -qudit are maximally mixed. We investigate the general constructions of -uniform pure quantum states of subsystems with levels. We provide one construction via symmetric matrices and the second one through the classical error-correcting codes. There are three main results arising from our constructions. First, we show that for any given even , there always exists an -uniform -qudit quantum state of level for sufficiently large prime . Second, both constructions show that there exist -uniform -qudit pure quantum states such that is proportional to , i.e., although the construction from symmetric matrices in general outperforms the one by error-correcting codes. Third, our symmetric matrix construction provides a positive answer to the open question on whether - here exists a 3-uniform -qudit pure quantum state for all . In fact, we can further prove that, for every , there exists a constant such that there exists a -uniform -qudit quantum state for all . In addition, by using the concatenation of algebraic geometry codes, we give an explicit construction of -uniform quantum state when tends to infinity.
Autors: Keqin Feng;Lingfei Jin;Chaoping Xing;Chen Yuan;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5618 - 5627
Publisher: IEEE
 

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