Electrical and Electronics Engineering publications abstract of: 01-2017 sorted by title, page: 5

» Data Monitoring and Hardware Control for App Android by Bluetooth Communication for Laboratory Teaching in Electrical Engineering Courses
Abstract:
For the formation of a professional in engineering, it is necessary that the knowledge gained in the classroom can be applied in practice. Based on this issue, this paper reports the study and development of a prototype that uses prototyping tools and creating an Android application capable of performing reading analog variables and hardware control via Bluetooth communication to be used in laboratory teaching . The study on the theoretical foundation involves the review of concepts from the application of practical teaching labs to the technology areas related to the project, such as Arduino and Android platforms. The work continues with the prototype development methodology, which are detailed all stages of development of the proposed system, the components that constitute the programming tools used and the final results of the prototype already in operation. Throughout the article, we report the tests to validate the prototype and the results obtained. Finally, we observe them design features and the feasibility of its application in academia.
Autors: Lucas Boaroli;Anderson Diogo Spacek;Cleber Lourenco Izidoro;Joao Mota Neto;Everlise Maestrelli;Oswaldo Hideo Ando Junior;
Appeared in: IEEE Latin America Transactions
Publication date: Jan 2017, volume: 15, issue:1, pages: 31 - 39
Publisher: IEEE
 
» Data Treasure Hunters: Science Expanding to New Frontiers [In the Spotlight]
Abstract:
Autors: Wade Trappe;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 116 - 115
Publisher: IEEE
 
» DC Railway System Emulator for Stray Current and Touch Voltage Prediction
Abstract:
A system to emulate railway dc systems is presented in this paper. The emulator is designed to simulate the behavior of railway systems in terms of stray currents and touch voltages. Power electronics circuits are used as variable resistors to simulate the train motion. The emulator provides a test bed to not only study and analyze the effects of stray currents and touch voltages, but also to evaluate techniques that mitigate these effects before they are physically implemented. The proposed emulator system is verified through simulation studies and hardware experimentations.
Autors: Amr Ibrahem;Ali Elrayyah;Yilmaz Sozer;J. Alexis De Abreu-Garcia;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 439 - 446
Publisher: IEEE
 
» DC Ultrahigh Voltage Insulation Technology for 1 MV Power Supply System for Fusion Application
Abstract:
To realize dc 1 MV power supply system for neutral beam injector in ITER, long-pulse dc ultrahigh-voltage (HV) insulation technologies have been developed. For a dc 1 MV insulating transformer, a composite bushing has been newly developed to overcome the manufacturing difficulty of a conventional condenser bushing (CB). The composite bushing has a small-sized CB and fiber reinforced plastic tube to sustain 1 MV stably inside and outside of the bushing. The mock-up of the insulating transformer has fulfilled the ITER requirement of dc 1.2 MV insulation for 3600 s. An HV bushing to transmit multiple voltages simultaneously has also been developed through a careful experimental study on vacuum insulation characteristics with multiple gaps between large electrodes. It has been found that the voltage holding is dominated not by number of the electrodes but by a total cathode surface area of electrodes. Based on this result, the vacuum insulation inside the HV bushing with five electrostatic screens has been designed to realize a stable vacuum insulation of 1 MV.
Autors: H. Tobari;K. Watanabe;M. Kashiwagi;H. Yamanaka;T. Maejima;Y. Terunuma;A. Kojima;M. Dairaku;M. Hanada;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 162 - 169
Publisher: IEEE
 
» Dead Time Effect on the Double-Loop Control Strategy for a Boost Inverter
Abstract:
The boost inverter topology achieves both boosting and inversion in a single stage. Various controllers have been implemented on boost inverters to obtain stable operation. However, the double-loop control strategy is the most appropriate because it provides good performance under nonlinear loads, abrupt load variations, and transient short-circuit conditions. The double-loop control strategy was introduced with proportional integral (PI) controllers used in each loop. Recently, with the widespread use of proportional resonant (PR) controllers, the PI controllers were replaced with the PR controllers to achieve zero steady-state error for the ac components of the reference. However, during the implementation of the PR controllers, a significant dc offset in the output voltage of the boost inverter was observed. Furthermore, the output voltages of the boost converters showed a clipping effect. In this paper, it is shown that the dc offset and the clipping of the boost converters are attributed to the dead time and parameter mismatch between the boost converters. A new controller is proposed to reduce the dc offset and clipping effect. The improved performance of the proposed controller is demonstrated with experimental results on a boost inverter prototype.
Autors: Otshepeng J. Moraka;Paul S. Barendse;Mohamed Azeem Khan;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 319 - 326
Publisher: IEEE
 
» Decentralized Contingency-Constrained Tie-Line Scheduling for Multi-Area Power Grids
Abstract:
Tie-line scheduling (TS) becomes a practical need for growing interconnection of regional power grids and the increasing integration of renewable energy. In electricity markets without a coordination organization, TS should be handled in a fully decentralized manner, where the impact of contingencies should also be considered for operational reliability. In this paper, the contingency-constrained TS (CCTS) problem is formulated using a two-stage robust optimization (RO) scheme to consider the security criterion. This robust model is decomposed and handled by the alternating direction multiplier method (ADMM) in a fully decentralized way, where the column-and-constraint generation (C&CG) is incorporated to solve the regional robust subproblems. Three computational strategies are also developed to enhance the computation efficiency of the decentralized algorithm. Numerical simulations are given to study the computational performance, the solution quality, and scalability of the proposed method.
Autors: Zhigang Li;Wenchuan Wu;Bo Zeng;Mohammad Shahidehpour;Boming Zhang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 354 - 367
Publisher: IEEE
 
» Decentralized Intraday Generation Scheduling for Multiarea Power Systems via Dynamic Multiplier-Based Lagrangian Relaxation
Abstract:
Due to day-ahead forecast error in load demand and renewable generation, there exists inevitable deviation between real-time operation and day-ahead generation schedules. This paper introduces a decentralized multiarea intraday generation scheduling based on nonlinear ac power flow. This approach allows for a more reliable and economic operation with the ability to accurately constrain power and voltage securities at a multiarea scale. A dynamic multiplier-based algorithm is employed for solving the nonlinear multiarea intraday dispatch model, which is fully decentralized and thus preserves autonomy for each area. The dynamic multiplier-based algorithm presents the advantage of accelerated computation compared to conventional static multiplier. Numerical simulations illustrate the computational performance and practical value of the proposed multiarea intraday generation scheduling framework and dynamic multiplier-based algorithm.
Autors: Xiaowen Lai;Haiwang Zhong;Qing Xia;Chongqing Kang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 454 - 463
Publisher: IEEE
 
» Decentralized Robust Synchronization of Unknown High Order Nonlinear Multi-Agent Systems With Prescribed Transient and Steady State Performance
Abstract:
In this paper, we consider the synchronization control problem for uncertain high-order nonlinear multi-agent systems in a leader-follower scheme, under a directed communication protocol. A robust decentralized control law of minimal complexity is proposed that achieves prescribed, arbitrarily fast and accurate synchronization of the following agents with the leader. The control protocol is decentralized in the sense that the control signal of each agent is calculated based solely on local relative state information from its neighborhood set. Additionally, no information regarding the agents' dynamic model is employed in the design procedure. Moreover, provided that the communication graph is connected and contrary to the related works on multi-agent systems, the controller-imposed transient and steady state performance bounds are fully decoupled from: 1) the underlying graph topology, 2) the control gains selection, and 3) the agents' model uncertainties, and are solely prescribed by certain designer-specified performance functions. Extensive simulation results clarify and verify the approach.
Autors: Charalampos P. Bechlioulis;George A. Rovithakis;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 123 - 134
Publisher: IEEE
 
» Decision Model for Resolving Conflicting Transit Signal Priority Requests
Abstract:
Resolving conflicting transit signal priority (TSP) requests has become an emerging topic in public transportation studies. The main objective of TSP is to reduce schedule deviation and enhance the reliability of bus service, whereas many previous studies have aimed at reducing priority delay. Furthermore, they did not take into account the element of waiting time experienced by passengers at bus stops. Therefore, this paper selects in-bus passenger delay and passenger waiting delay at next bus stops as the indexes to measure the priority level of TSP requests. Here, a decision model is proposed. It favors a bus with long delay and adds in-bus passenger delay and passenger waiting delay at next stops for buses requesting the same TSP actions. A case study is conducted to examine the performance of the proposed model, which was compared with the baseline model (no TSP), the conventional model (Model 1) using the first-in–first-service policy, and a typical optimization model (Model 2) developed in previous studies. Results show that the proposed model significantly outperformed the other three models. Specifically, the proposed model reduced average passenger waiting delay by 20.4%, 16.2%, and 12.2% over the baseline model, Model 1, and Model 2, respectively. The average in-bus passenger delay was reduced by 14.2% over the baseline method, by 10.3% over Model 1, and by 6.6% over Model 2. At the same time, the passenger delay of other vehicles for the proposed model was 8.8% and 4.8% lower than those of Model 1 and Model 2, respectively.
Autors: Zhirui Ye;Mingtao Xu;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2017, volume: 18, issue:1, pages: 59 - 68
Publisher: IEEE
 
» Decoding Upper Limb Movement Attempt From EEG Measurements of the Contralesional Motor Cortex in Chronic Stroke Patients
Abstract:
Goal: Stroke survivors usually require motor rehabilitation therapy as, due to the lesion, they completely or partially loss mobility in the limbs. Brain–computer interface technology offers the possibility of decoding the attempt to move paretic limbs in real time to improve existing motor rehabilitation. However, a major difficulty for the practical application of the BCI to stroke survivors is that the brain rhythms that encode the motor states might be diminished due to the lesion. This study investigates the continuous decoding of natural attempt to move the paralyzed upper limb in stroke survivors from electroencephalographic signals of the unaffected contralesional motor cortex. Results: Experiments were carried out with the aid of six severely affected chronic stroke patients performing/attempting self-selected reaching movements of the unaffected/affected upper limb. The electroencephalographic (EEG) analysis showed significant cortical activation on the uninjured motor cortex when moving the contralateral unaffected arm and in the attempt to move the ipsilateral affected arm. Using this activity, significant continuous decoding of movement was obtained in six out of six participants in movements of the unaffected limb, and in four out of six participants in the attempt to move the affected limb. Conclusion: This study showed that it is possible to construct a decoder of the attempt to move the paretic arm for chronic stroke patients using the EEG activity of the healthy contralesional motor cortex. Significance: This decoding model could provide to stroke survivors with a natural, easy, and intuitive way to achieve control of BCIs or robot-assisted rehabilitation devices.
Autors: Javier M. Antelis;Luis Montesano;Ander Ramos-Murguialday;Niels Birbaumer;Javier Minguez;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 99 - 111
Publisher: IEEE
 
» Decoupling and Performance Enhancement of Hybrid Control for Motion-Copying System
Abstract:
This paper proposes a structure for the decoupling and performance improvement of a hybrid control system. Additionally, the application of this system to a motion-copying system (MCS) is introduced. MCSs are proposed as a means of preserving human-skilled techniques. In the motion-saving phase, a bilateral controller (a type of position/force hybrid control system) is utilized. A decoupling controller is required for bilateral control, for realizing precise force and position reproduction. A conventional hybrid controller for bilateral control systems has been developed, based on a force controller, by using a modal space disturbance observer (DOB). However, deterioration in the system performance during changes in the configuration of the manipulator is observed in force controllers based on workspace DOBs. It is also found that another conventional bilateral controller based on a hybrid matrix generates an interference term in the force control system, if there is a difference between the masses of the master and slave systems. This study shows that an acceleration controller can also realize decoupling control in the modal space. Furthermore, a novel DOB for enhancing the performance of an acceleration controller is proposed. Additionally, it is shown that a saved human motion can be reproduced accurately, while maintaining the high transparency of the bilateral control, by implementing a structure based on a hybrid controller and using the proposed DOB. The validity of the proposal is confirmed through analyses and experiments.
Autors: Yuki Nagatsu;Seiichiro Katsura;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 420 - 431
Publisher: IEEE
 
» Deep Learning With Grouped Features for Spatial Spectral Classification of Hyperspectral Images
Abstract:
This letter presents a novel deep learning algorithm for feature extraction from the hyperspectral images. The proposed method takes advantage of the knowledge that the features of the spatial-spectral data naturally fall into an array of groups with respect to different spectral bands. Aiming to reduce the influence of redundant spectral bands adaptively using unlabeled hyperspectral data, we incorporate the group information in the training algorithm of the deep neural network via a regularized weight-decay process. Experiments over different benchmarks of hyperspectral images show that the proposed method provides competitive solution with the state-of-the-art approaches.
Autors: Xichuan Zhou;Shengli Li;Fang Tang;Kai Qin;Shengdong Hu;Shujun Liu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 97 - 101
Publisher: IEEE
 
» Deep Multitask Learning for Railway Track Inspection
Abstract:
Railroad tracks need to be periodically inspected and monitored to ensure safe transportation. Automated track inspection using computer vision and pattern recognition methods has recently shown the potential to improve safety by allowing for more frequent inspections while reducing human errors. Achieving full automation is still very challenging due to the number of different possible failure modes, as well as the broad range of image variations that can potentially trigger false alarms. In addition, the number of defective components is very small, so not many training examples are available for the machine to learn a robust anomaly detector. In this paper, we show that detection performance can be improved by combining multiple detectors within a multitask learning framework. We show that this approach results in improved accuracy for detecting defects on railway ties and fasteners.
Autors: Xavier Gibert;Vishal M. Patel;Rama Chellappa;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2017, volume: 18, issue:1, pages: 153 - 164
Publisher: IEEE
 
» Deeper and cheaper machine learning [Top Tech 2017]
Abstract:
Last March, Google's computers roundly beat the world-class Go champion Lee Sedol, marking a milestone in artificial intelligence. The winning computer program, created by researchers at Google DeepMind in London, used an artificial neural network that took advantage of what’s known as deep learning, a strategy by which neural networks involving many layers of processing are configured in an automated fashion to solve the problem at hand.
Autors: David Schneider;
Appeared in: IEEE Spectrum
Publication date: Jan 2017, volume: 54, issue:1, pages: 42 - 43
Publisher: IEEE
 
» Defect-Related Degradation of AlGaN-Based UV-B LEDs
Abstract:
This paper describes an extensive analysis of the degradation of (InAlGa)N-based UV-B light-emitting diodes (LEDs) submitted to constant current stress. This paper is based on combined electrical characterization, spectral analysis of the emission, deep-level transient spectroscopy (DLTS) and photocurrent (PC) spectroscopy. The results of this analysis demonstrate that: 1) UV-B LEDs show a gradual degradation when submitted to constant current stress; the decrease in optical power is stronger for low measuring current levels, indicating that degradation is related to the increase in Shockley–Read–Hall (SRH) recombination; 2) the current–voltage characteristics measured before/during stress show an increase in the current below the turn-on voltage, that is ascribed to the increase in trap-assisted tunneling (TAT) components; and 3) DLTS analysis and PC spectroscopy measurements were carried out to identify the properties of the defects responsible for the degradation of the optical and electrical characteristics. The results indicate that stress induces or activates defects centered around 2.5 eV below the conduction band edge. These defects, close to midgap, can explain both the increased SRH recombination and the increase in TAT components detected after stress. Moreover, the DLTS measurements allowed to identify the signature of Mg-related acceptor traps.
Autors: Desiree Monti;Matteo Meneghini;Carlo De Santi;Gaudenzio Meneghesso;Enrico Zanoni;Johannes Glaab;Jens Rass;Sven Einfeldt;Frank Mehnke;Johannes Enslin;Tim Wernicke;Michael Kneissl;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 200 - 205
Publisher: IEEE
 
» Definition of QoE Fairness in Shared Systems
Abstract:
User-centric service and application management focuses on the quality of experience (QoE) as perceived by the end user. Thereby, the goal is to maximize QoE while ensuring fairness among users, e.g., for resource allocation and scheduling in shared systems. Although the literature suggests to consider consequently QoE fairness, there is currently no accepted definition of QoE fairness. The contribution of this letter is the definition of a generic QoE fairness index , which has desirable key properties as well as the rationale behind it. By using examples and a measurement study involving multiple users downloading web content over a bottleneck link, we differentiate the proposed index from QoS fairness and the widely used Jain’s fairness index. Based on results, we argue that neither QoS fairness nor Jain’s fairness index meet all of the desirable QoE-relevant Properties, which are met by . Consequently, the proposed index may be used to compare QoE fairness across systems and applications, thus serving as a benchmark for QoE management mechanisms and system optimization.
Autors: Tobias Hoßfeld;Lea Skorin-Kapov;Poul E. Heegaard;Martin Varela;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 184 - 187
Publisher: IEEE
 
» Degradation Mechanisms of Amorphous InGaZnO Thin-Film Transistors Used in Foldable Displays by Dynamic Mechanical Stress
Abstract:
Foldable displays represent one of the most attractive next-generation display applications. Therefore, it is critical to analyze the effects of mechanical stress on amorphous InGaZnO (a-IGZO) thin-film-transistors (TFTs) in order to apply them to foldable displays. In foldable display applications, the dynamic mechanical stress tests are designed to be carried out using a bending radius of less than 3 mm. In this paper, dynamic mechanical bending stress tests are performed on a-IGZO TFTs using various bending radii and directions in order to examine the instability characteristics of the TFTs. In addition, the degradation mechanisms are investigated using a technology computer-aided design simulation. As a result, we have demonstrated that it is now possible to establish reliable circuit guidelines for using a-IGZO TFTs in foldable display applications.
Autors: Sang Myung Lee;Dongseok Shin;Ilgu Yun;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 170 - 175
Publisher: IEEE
 
» Dehashing: Server-Side Context-Aware Feature Reconstruction for Mobile Visual Search
Abstract:
Due to the prevalence of mobile devices, mobile search becomes a more convenient way than desktop search. Different from the traditional desktop search, mobile visual search needs more consideration for the limited resources on mobile devices (e.g., bandwidth, computing power, and memory consumption). The state-of-the-art approaches show that the bag-of-words (BoW) model is robust for image and video retrieval; however, the large vocabulary tree might not be able to be loaded on the mobile device. We observe that recent works mainly focus on designing compact feature representations on mobile devices for bandwidth-limited network (e.g., 3G) and directly adopt feature matching on remote servers (cloud). However, the compact (binary) representation might fail to retrieve target objects (images and videos). Based on the hashed binary codes, we propose a dehashing process that reconstructs BoW by leveraging the computing power of remote servers. To mitigate the information loss from binary codes, we further utilize contextual information (e.g., GPS) to reconstruct a context-aware BoW for better retrieval results. Experiment results show that the proposed method can achieve competitive retrieval accuracy as BoW while only transmitting few bits from mobile devices.
Autors: Yin-Hsi Kuo;Winston H. Hsu;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jan 2017, volume: 27, issue:1, pages: 139 - 148
Publisher: IEEE
 
» Delay Insensitive Signal-Injection Calibration for Large Antenna Arrays Using Passive Hierarchical Networks
Abstract:
Efficient beamforming of phased-array antennas requires that the phase delay of each channel is accurately known. One technique for achieving this is to distribute a calibration or local-oscillator reference signal through a delay-insensitive signal distribution network. In this paper, we propose using passive hierarchical signal distribution networks to distribute such signals, a method that scales significantly better with the size of the array than existing signal distribution methods. We analyze the impact of impedance variations within the network on the phase accuracy and propose a calibration front-end architecture. This front end also enables the return loss and coupling between antennas to be monitored for diagnostic purposes. We present an implementation of this front end that was applied to a small prototype antenna array, and show that this implementation exhibited low sensitivity to delays within the calibration network, reduced the temperature-dependent phase error of the front ends substantially, and can be used for performing antenna return-loss measurements.
Autors: Johan Borg;Jonny Johansson;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 190 - 195
Publisher: IEEE
 
» Delay Minimization in Real-Time Communications With Joint Buffering and Coding
Abstract:
We present a closed-form expression for the minimal delay that is achievable in a setting that combines a buffer and an erasure code, used to mitigate the packet delay variance. The erasure code is modeled according to the recent information-theoretic results on finite block length codes. Evaluations reveal that accurate knowledge of the network parameters is essential for optimal operation. Moreover, it is shown that, when the network packet delay variance is large, the buffer delay becomes negligible. Therefore, in this case, the delay budget should be spent mainly on the erasure code.
Autors: Jesper H. Sørensen;Petar Popovski;Jan Østergaard;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 52 - 55
Publisher: IEEE
 
» Demagnetization of a Complete Superconducting Radiofrequency Cryomodule: Theory and Practice
Abstract:
A significant advance in magnetic field management in a fully assembled superconducting radiofrequency cryomodule has been achieved and is reported here. Demagnetization of the entire cryomodule after assembly is a crucial step toward the goal of average magnetic flux density less than 0.5 μT at the location of the superconducting radio frequency cavities. An explanation of the physics of demagnetization and experimental results are presented.
Autors: Saravan K. Chandrasekaran;Anthony C. Crawford;
Appeared in: IEEE Transactions on Applied Superconductivity
Publication date: Jan 2017, volume: 27, issue:1, pages: 1 - 6
Publisher: IEEE
 
» Demand Response: Social Welfare Maximization in an Unbundled Energy Market Case Study for the Low-Voltage Networks of a Distribution Network Operator in The Netherlands
Abstract:
With the introduction of smart meters, dynamic pricing, and home energy management systems, residential customers are able to react to changes in electricity prices. In an unbundled market, the energy supplier and the network operator may have conflicting interests with respect to demand response (DR) programs. As customer participation is essential to a well-functioning DR program, it is needed to assess which DR programs offer most customer benefits. Two DR program options are analyzed for low-voltage feeders: a program from the energy supplier based on the electricity price, and a DR program from the network operator based on the loading of the network. Depending on the network topology the benefits can change significantly between the two DR programs. DR from an energy supplier point of view might induce undervoltages which lead to additional network reinforcements, while load shifting from a network point of view can generate higher electricity cost.
Autors: Michiel Nijhuis;Muhammad Babar;Madeleine Gibescu;Sjef Cobben;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 32 - 38
Publisher: IEEE
 
» Demonstration of Counter-Propagating Raman Pump Placed Near Signal-Channel Wavelengths
Abstract:
As optical-fiber capacity is increased by the use of multiple signal bands such as the combined S+C+L bands, signals in the -band may have to co-exist with Raman pumps operating in nearby wavelength slots. We investigate the impact of placing a counter-propagating Raman pump near a 32-Gbd polarization-division-multiplexed 16-ary quadrature-amplitude-modulated signal.
Autors: A. H. Gnauck;R. M. Jopson;P. J. Winzer;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 154 - 157
Publisher: IEEE
 
» Demonstration of Optical FEC Coding Scheme With Convolutional Code Consisting of a Signal Source
Abstract:
In this letter, we experimentally demonstrated an all-optical forward error correction (FEC) coding scheme with the convolutional code using a single signal source to compensate time-dependent noise. The proposed coding scheme was comprised of optical XOR gates, delay lines, and optical wavelength converters, which are based on four-wave mixing in highly non-linear fibers. The temporal waveforms of the optical FEC coding scheme were experimentally achieved for 10 Gb/s return-to-zero differential phase shift keying (RZ-DPSK) signals modulated with , and the obtained idler signals accurately corresponded to the code between any input signals. Under the optimized conditions of operational wavelengths, the proposed scheme theoretically offered 4.0 and 3.5 dB net coding gains for the conditions of BER and BER , respectively, owing to its small power penalties.
Autors: Yohei Aikawa;Hiroyuki Uenohara;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 165 - 168
Publisher: IEEE
 
» Deriving Maximum Light Use Efficiency From Crop Growth Model and Satellite Data to Improve Crop Biomass Estimation
Abstract:
Maximum light use efficiency () is an important parameter in biomass estimation models (e.g., the Production Efficiency Models (PEM)) based on remote sensing data; however, it is usually treated as a constant for a specific plant species, leading to large errors in vegetation productivity estimation. This study evaluates the feasibility of deriving spatially variable crop from satellite remote sensing data. at the plot level was retrieved first by assimilating field measured green leaf area index and biomass into a crop model (the Simple Algorithm for Yield estimate model), and was then correlated with a few Landsat-8 vegetation indices (VIs) to develop regression models. was then mapped using the best regression model from a VI. The influence factors on variability were also assessed. Contrary to a fixed , our results suggest that is affected by environmental stresses, such as leaf nitrogen deficiency. The strong correlation between the plot-level and VIs, particularly the two-band enhanced vegetation index for winter wheat (Triticum aestivum) and the green chlorophyll index for maize (Zea mays) at the milk stage, provided a potential to deri- e from remote sensing observations. To evaluate the quality of derived from remote sensing data, biomass of winter wheat and maize was compared with that estimated using a PEM model with a constant and the derived variable . Significant improvements in biomass estimation accuracy were achieved (by about 15.0% for the normalized root-mean-square error) using the derived variable . This study offers a new way to derive for a specific PEM and to improve the accuracy of biomass estimation using remote sensing.
Autors: Taifeng Dong;Jiangui Liu;Budong Qian;Qi Jing;Holly Croft;Jingming Chen;Jinfei Wang;Ted Huffman;Jiali Shang;Pengfei Chen;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 104 - 117
Publisher: IEEE
 
» Description of an Electrodynamic Self-Bearing Permanent Magnet Machine
Abstract:
This paper aims to give a description of a passively levitated self-bearing permanent magnet motor principle. The windings of a permanent magnet motor are connected in such a way that they are also coupled to the 1 harmonics due to a rotor off-centering. They allow for eddy currents to flow inside a short-circuit path when the rotor is out-centered, and in consequence to generate radial force according to the principle of radial heteropolar electrodynamic bearings. The general principles are described, and a 2-D-FE time-dependent model illustrates those principles on two application cases. The theoretical feasibility of this passively levitated permanent magnet motor is shown on a slotless application case.
Autors: Virginie Kluyskens;Corentin Dumont;Bruno Dehez;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 9
Publisher: IEEE
 
» Design and Analysis of an Axial Flux Magnetically Geared Generator
Abstract:
Axial flux magnetically geared machines offer the potential to achieve exceptional torque densities at high diameters. This paper proposes a topology for an axial flux magnetically geared machine, in which the electric machine is placed in the bore of the axial flux magnetic gear. This new topology offers the advantage of correctly matching the size of the electric machine to its required torque without increasing the volume of the system beyond that of the magnetic gear. A proof-of-concept prototype with a torque density of was designed, fabricated, and tested to evaluate the novel topology. A less conservative alternate design capable of achieving was also simulated to demonstrate the topology's potential for high torque densities, and even higher torque densities can be reached at larger scale designs.
Autors: Matthew Johnson;Matthew C. Gardner;Hamid A. Toliyat;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 97 - 105
Publisher: IEEE
 
» Design and Fabrication of a Conceptual Arterial Ultrasound Phantom Capable of Exhibiting Longitudinal Wall Movement
Abstract:
The longitudinal movement of the arterial wall of large human arteries has shown promise to be an independent indicator of vascular health. Despite growing interest in this movement, its nature, causes, and implications are not fully understood, and existing phantoms have failed to show a pure longitudinal movement that is not secondary to the distension. An often overlooked aspect of the arterial wall is the interaction between the different layers. The longitudinal movement of the innermost layers, the intima and media, can be several hundred micrometers in the direction of flow during early systole. This is markedly larger than that of the adventitia, indicating that sliding occurs between the two layers. This feature was incorporated into a phantom by casting it in two parts. The molds were developed in-house using mainly a 3-D printer, a versatile and easy production method. Additionally, the phantom contains a tapered region. Using the phantom, we were able to demonstrate a pure longitudinal movement; when it was subjected to a pulsatile pressure, the wall displaced 220 (SD 40) radially and 560 (SD 74) longitudinally distal to the tapering. The motion followed the pressure variations. This paper serves as a guide for phantom production, explaining each step of the process.
Autors: Sandra Sjöstrand;Alice Widerström;Åsa Rydén Ahlgren;Magnus Cinthio;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Jan 2017, volume: 64, issue:1, pages: 11 - 18
Publisher: IEEE
 
» Design and Implementation of a Teaching Tool for Introduction to object-oriented programming
Abstract:
Object-oriented programming (OOP) is a programming paradigm in which programs are organized as cooperative collections of object. Learning the object-oriented approach is however difficult for novice students, mostly because the concepts of object, class and inheritance are abstract in nature. The main objective of this article is to present the design and validation of a learning environment for learning the concepts of object-oriented programming. The learning environment is based on Polya's heuristic method for solving problems. The validation process was performed using a pretest and post-test applied to two groups: control and experimental. The results given in the validation demonstrate evidence that experimental group recorded a higher level of consolidation of the concepts of object-oriented programming.
Autors: Adriana Joaquina Olier Quiceno;Adan Alberto Gomez Salgado;Manuel Fernando Caro Pineres;
Appeared in: IEEE Latin America Transactions
Publication date: Jan 2017, volume: 15, issue:1, pages: 97 - 102
Publisher: IEEE
 
» Design and Modeling of a Six-Degree-of-Freedom Magnetically Levitated Positioner Using Square Coils and 1-D Halbach Arrays
Abstract:
This paper presents a novel design of six-degree-of-freedom (6-DOF) magnetically levitated (maglev) positioner, where its translator and stator are implemented by four groups of 1-D Halbach permanent-magnet (PM) arrays and a set of square coils, respectively. By controlling the eight-phase square coil array underneath the Halbach PM arrays, the translator can achieve 6-DOF motion. The merits of the proposed design are mainly threefold. First, this design is potential to deliver unlimited-stroke planar motion with high power efficiency if additional coil switching system is equipped. Second, multiple translators are allowed to operate simultaneously above the same square coil stator. Third, the proposed maglev system is less complex in regard to the commutation law and the phase number of coils. Furthermore, in this paper, an analytical modeling approach is established to accurately predict the Lorentz force generated by the square coil with the 1-D Halbach PM array by considering the corner region, and the proposed modeling approach can be extended easily to apply on other coil designs such as the circular coil, etc. The proposed force model is evaluated experimentally, and the results show that the approach is accurate in both single- and multiple-coil cases. Finally, a prototype of the proposed maglev positioner is fabricated to demonstrate its 6-DOF motion ability. Experimental results show that the root-mean-square error of the implemented maglev prototype is around 50 nm in planar motion, and its velocity can achieve up to 100 mm/s.
Autors: Haiyue Zhu;Tat Joo Teo;Chee Khiang Pang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 440 - 450
Publisher: IEEE
 
» Design and Optimization for Energy-Efficient Cooperative MIMO Transmission in Ad Hoc Networks
Abstract:
The need to reduce energy consumption for lowering operating costs has pushed energy efficiency to become one of the major issues of current research in the field of ad hoc networks. In this paper, a new cooperative strategy of multiple-input–multiple-output (MIMO) based on spatial modulation (SM) for the randomly distributed nodes (CMIMO-SMR) in an ad hoc network is proposed to optimize the whole energy consumption of the network. In this new strategy, the head node and the assistant node are jointly set up using a cooperative technique in each cluster to obtain the diversity. In this strategy, the effect of the amount of nodes on the energy consumption is analyzed. Moreover, the different factors such as number of hops and bit error ratio (BER) for energy savings are investigated in a CMIMO-SMR-based multihop ad hoc network where the optimal number of hops and the BER relationship are derived by taking into account the transmission energy and the circuit energy, as well as the bit-recovery situation. In the simulation, it is demonstrated that CMIMO-SMR is more energy efficient compared with the existing works. Moreover, an adaptive algorithm for choosing the appropriate number of hops to minimize the energy consumption is designed when the end-to-end designated BER is required. The results demonstrate that the minimum energy consumption can be achieved by using the proposed algorithm without compromising the designated BER requirement at the destination.
Autors: Yuyang Peng;Fawaz Al-Hazemi;Heejae Kim;Chan-Hyun Youn;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 710 - 719
Publisher: IEEE
 
» Design and Optimization of Small Inductors on Extra-Thin PCB for Flexible Cooking Surfaces
Abstract:
The following paper describes the design and optimization method for a small inductor in printed circuit board, which is later used in the implementation of a flexible cooking surface prototype. The method combines analytical developments with finite element analysis (FEA) simulations, providing an important decrease of the computational costs. This is followed by the corresponding calculations in order to minimize conduction and proximity losses in the winding by optimizing the copper volume in the winding and the conductor cross-section dimensions. A parametric analysis is carried out to define the induction system that leads to the optimal efficiency, which, moreover, proves extra-thin PCBs as the most suitable solution. A laboratory prototype of a flexible cooking surface was implemented and tested under real working conditions. The empirical characterization produced good results, which are consistent with the simulations. Additionally, the correct thermal behavior of the arrangement and its adaptability to different pot sizes was verified.
Autors: Javier Serrano;Ignacio Lope;Jesús Acero;Claudio Carretero;José Miguel Burdío;Rafael Alonso;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 371 - 379
Publisher: IEEE
 
» Design and Performance Analysis of Nonlinearity Preprocessors in an Impulsive Noise Environment
Abstract:
This paper discusses a practical design of nonlinearity preprocessors to be used in a receiver for mitigating performance degradation in an impulsive noise environment. A simple method is proposed for a blanker and a soft limiter to calculate a blanking and a clipping threshold, respectively. In addition, to evaluate the bit error performance of a receiver with the proposed nonlinearity preprocessors, this paper introduces an approach using a periodic pulse train function and Fourier series. When a nonlinearity preprocessor is used, since the output samples show a truncated probability density function, it is generally difficult to evaluate the bit error performance of a receiver. Analytical and simulation results show that the thresholds computed by the proposed method are near optimal in terms of efficacy function and that the error performance of the proposed nonlinearity preprocessors matches well with that of the ideal design of nonlinearity preprocessors with optimal thresholds.
Autors: Hyungkook Oh;Haewoon Nam;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 364 - 376
Publisher: IEEE
 
» Design and Simulation of Low-Power Logic Gates Based on Nanoscale Side-Contacted FED
Abstract:
A new nanoscale device has been already introduced as a side-contacted field effect diode (S-FED), which is composed of a diode and planar SOI-MOSFET. In this paper, S-FED is optimized in terms of work function, with due attention to the design of logic gates, such as NOT, NAND, NOR, and XOR. Results demonstrate that optimum work function is 4.7 eV in which the highest value of can be achieved. Mixed-mode simulations are used to determine the performance of the proposed logic gates. Also, the proof regarding the mitigation of the total power consumption up to 56% is presented so that not gate based on S-FED improves power delay product by about 30%, compared with the CMOS-based version. A similar fabrication process with the CMOS technology could be asserted as the considerable advantage to pave the way of feasibly realizing the new generation of S-FED-based logic gates.
Autors: Behnam Jafari Touchaei;Negin Manavizadeh;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 306 - 311
Publisher: IEEE
 
» Design and Validation of a Novel MR-Compatible Sensor for Respiratory Motion Modeling and Correction
Abstract:
Goal: A novel magnetic resonance (MR) compatible accelerometer for respiratory motion sensing (MARMOT) is developed as a surrogate of the vendors’ pneumatic belts. We aim to model and correct respiratory motion for free-breathing thoracic-abdominal MR imaging and to simplify patient installation. Methods: MR compatibility of MARMOT sensors was assessed in phantoms and its motion modeling/correction efficacy was demonstrated on 21 subjects at 3 T. Respiration was modeled and predicted from MARMOT sensors and pneumatic belts, based on real-time images and a regression method. The sensor accuracy was validated by comparing motion errors in the liver/kidney. Sensor data were also exploited as inputs for motion-compensated reconstruction of free-breathing cardiac cine MR images. Multiple and single sensor placement strategies were compared. Results: The new sensor is compatible with the MR environment. The average motion modeling and prediction errors with MARMOT sensors and with pneumatic belts were comparable (liver and kidney) and were below 2 mm with all tested configurations (belts, multiple/single MARMOT sensor). Motion corrected cardiac cine images were of improved image quality, as assessed by an entropy metric (p  <  10−6), with all tested configurations. Expert readings revealed multiple MARMOT sensors were the best (p  <  0.03) and the single MARMOT sensor was similar to the belts (nonsignificant in two of the three readers). Conclusion: The proposed sensor can model and predict respiratory motion with sufficient accuracy to allow free-breathing MR imaging strategy. Significance: It provides an alternative sensor solution for the respiratory motion prob- em during MR imaging and may improve the convenience of patient setup.
Autors: Bailiang Chen;Nicolas Weber;Freddy Odille;Claire Large-Dessale;Antoine Delmas;Laurent Bonnemains;Jacques Felblinger;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 123 - 133
Publisher: IEEE
 
» Design Approach for Multiband Horn Antennas Mixing Multimode and Hybrid Mode Operation
Abstract:
The design of a quad-band (18, 28, 38, and 48 GHz) feed horn is presented. Corrugations are used for a good polarization purity at the higher frequencies. At the lower frequency, they act as a smooth wall and the horn profile is tuned to achieve a high aperture efficiency.
Autors: J.-P. Adam;M. Romier;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 358 - 364
Publisher: IEEE
 
» Design Consideration on the Square-Wave Voltage Injection for Sensorless Drive of Interior Permanent-Magnet Machines
Abstract:
Although it is widely known that the saliency-based position-sensorless drive is able to achieve the closed-loop control at zero and low speed, there is little literature addressing the consideration on the selection of injection voltage frequency. This paper evaluates the square-wave injection voltage at different frequencies for the design of an interior permanent-magnet (PM) machine sensorless drive. It is shown that more flux saturation on high-frequency (HF) d-axis inductance occurs than the saturation on q-axis inductance due to the magnetic relaxation. The HF saliency ratio is increased by increasing the injection frequency. The performance of a saliency-based sensorless drive can be enhanced by properly designing the frequency of injection voltage. This paper also includes the experimental comparison between closed-loop encoder-based and closed-loop saliency-based sensorless operation of an interior PM machine drive.
Autors: Shih-Chin Yang;Sheng-Ming Yang;Jing- Hui Hu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 159 - 168
Publisher: IEEE
 
» Design Fiction: Anticipating Adoption
Abstract:
This tutorial highlights the potential of design fiction with Game of Drones, a fictional user trial of an imagined Drone Enforcement System. The authors explore a potential future use of drones for civic enforcement activities and advance a program for developing design fiction as a research method. This method provides a means for exploring the societal, technological, and political nuances of possible futures so researchers can better consider possible adoption pathways for emerging technologies. This tutorial is part of a special issue on drones.
Autors: Paul Coulton;Joseph Lindley;
Appeared in: IEEE Pervasive Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 43 - 47
Publisher: IEEE
 
» Design Methodology of a Printed WPT System for HF-Band Mid-Range Applications Considering Human Safety Regulations
Abstract:
A methodology for the design of printed magnetically coupled resonant wireless power-transfer (WPT) systems is proposed. The design methodology aims at a well-matched system with a maximized power-transfer efficiency for mid-range applications. The system consists of two identical resonant coils driven by high-quality factor loops. The proposed design criteria allows obtaining maximum achievable transfer efficiency and impedance matching at any defined distance without any external matching circuits connected to the driven loops. For validation purposes, a printed WPT system at 10 MHz is fabricated targeting 1-m distance between the transmitting and receiving sides. Its performances in terms of reflection and transmission coefficients, as well as in terms of generated electric and magnetic fields, have been characterized numerically and experimentally. The impact of human body presence on the system has also been investigated observing the splitting in two frequencies of the common resonant frequency of the coils. A dosimetric study has been conducted using a detailed high-resolution anatomical human body model and considering , , and specific absorption rate (SAR) (local and whole body averaged SAR) as exposure metrics. It has been observed that peak exposure levels appear in different tissues depending on the body location. Compliance with the international commission on nonionizing radiation protection (ICNIRP) reference level as well as basic restrictions has been studied followed by computing the maximum allowable input power. It has been found that, with the body located 1 m away from the transmitting coil, the maximum allowable input power satisfying is in the order of MW, whereas it reduces to tens of ki- owatt when considering SAR and . The latter has been noticed to be the most restrictive dosimetric quantity.
Autors: Mohsen Koohestani;Maxim Zhadobov;Mauro Ettorre;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 270 - 279
Publisher: IEEE
 
» Design of a 90.9% Locking Range Injection-Locked Frequency Divider With Device Ratio Optimization in 90-nm CMOS
Abstract:
A 12–32 GHz divide-by-2 (D2) injection-locked frequency divider (ILFD) is presented in this paper. First, the device ratio of the injection mixer and cross-coupled pair is optimized to achieve a wide locking range (LR). Then, the inductive peaking and forward-body-bias techniques are applied to the injection mixer to boost its transconductance and to enhance injection efficiency for further extension of the LR. Finally, the harmonic suppression technique is introduced to reduce the output harmonics. Using the aforementioned approaches, we successfully demonstrate a D2 ILFD implemented in the 90-nm low-power CMOS technology with a maximum LR of 90.9% at an injection power of 0 dBm. Even with the injection power as low as −10 dBm, the proposed ILFD maintains an LR of 32.9%. This ILFD consumes 2.4 mW with a supply voltage of 0.6 V in a chip size of 0.45 mm2.
Autors: Jen-Hao Cheng;Jeng-Han Tsai;Tian-Wei Huang;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 187 - 197
Publisher: IEEE
 
» Design of a Broadband Quasi-Optical Mode Converter for $W$ -Band Gyro-TWTs
Abstract:
Mode converters for millimeter waves can reduce the transmission loss, generate the desired mode, and facilitate the application of high-power sources. A W-band broadband quasi-optical mode converter which converts a TE0,1 cylindrical waveguide mode into a linearly polarized Gaussian TEM00 mode has been realized and tested in this paper. The converter is composed of a wavefront transforming mirror, a polarization grating, and a phase correcting system. In order to obtain high conversion efficiency over a wide bandwidth and make the structure of the mode converter much simple and compact, the propagation path of the beam is optimized and a wavefront transforming mirror realized by an ellipsoidal mirror rather than a nonquadratic mirror is introduced. The conversion process in each section is displayed and the working principles are discussed in detail. The mode conversion characteristics are investigated by analyzing the measured radiation field pattern. Results of the measurement agree well with the numerical calculations. The proposed W-band mode converter has a conversion bandwidth of 21% when the mode conversion efficiency is over 95% and the cross polarization is below 1.7%. In addition to high conversion efficiency, low cross-polarization, and broad bandwidth, this converter features easy construction and compact structure.
Autors: Hao Li;Zewei Wu;Jianfan Zeng;Walter Kasparek;Yong Luo;Tianming Li;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 28 - 35
Publisher: IEEE
 
» Design of a Multilayer Graphene-Based Ultrawideband Terahertz Absorber
Abstract:
In this paper, an step by step efficient design procedure for designing a multilayer absorber using graphene thin films is presented. The absorber design is based on scattering parameters of plasmonic waves propagating on the surface of graphene layers. We have provided appropriate interpretations for designing different features of the absorber including graphene pattern and substrate material. We have also presented a multilayer graphene-based ultrawideband terahertz absorber that is designed using the proposed method. Presented absorber has perfect absorption over 2.7 THz and its central frequency is about 3 THz, which is an acceptable fractional bandwidth ultrawideband absorbers.
Autors: Alireza Fardoost;Fatemeh Ghaedi Vanani;As’ad Amirhosseini;Reza Safian;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jan 2017, volume: 16, issue:1, pages: 68 - 74
Publisher: IEEE
 
» Design of a Wideband System for Measuring Dielectric Properties
Abstract:
A dielectric object placed in the near-field region of an antenna produces a scattered field, which alters the input impedance of the antenna. This property can be used to measure the electric parameters of dielectric materials. A wideband system for measuring the dielectric properties in the frequency range from 1.1 to 3.5 GHz is designed and prototyped. The system consists of a wideband directional antenna, a wideband radio frequency circuit, and a data processing unit and has been tested by using different dielectric samples across the frequency band, and good measurement results have been obtained.
Autors: Xiangzhen Wang;Wen Geyi;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2017, volume: 66, issue:1, pages: 69 - 76
Publisher: IEEE
 
» Design of an Adaptive Multiresolution $M$ -Ary DCSK System
Abstract:
Multiresolution -ary differential chaos shift keying (MR--DCSK) system enables unequal-priority transmission via exploiting non-uniformly spaced phase constellations. In this letter, an adaptive MR--DCSK system is proposed by using a new constellation parameter design. Aiming at maximizing the spectral efficiency, the constellation parameter is carefully selected based on signal-to-noise ratio, and then is further optimized by a new search algorithm. Both the analytical and simulation results show that the proposed adaptive MR--DCSK system not only can enhance the spectral efficiency as compared with the adaptive -DCSK system, but can satisfy different bit-error-rate requirements for different bits within a symbol as well.
Autors: Guofa Cai;Yi Fang;Guojun Han;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 60 - 63
Publisher: IEEE
 
» Design of Compact HTS Dual-Band Bandpass Filters Using Dual-Function Feeding Structure With Wide Stop-Band Response
Abstract:
We have developed a compact high-temperature superconducting four-pole dual-band bandpass filter (DBPF) using a dual-function feeding structure with a wide stop-band response. Use of shorted stub-loaded hairpin resonators enabled its achievement. The coupling coefficients are flexibly controlled by using a pair of H-shaped coupling elements between the resonators. A dual-function feeding structure is newly developed for flexibly adjusting the external coupling for the two bands. A tapped-line coupling is used to adjust the external coupling for the first band, and a coupled-line coupling is used to adjust the external coupling for the second one. The DBPF was designed to operate at 0.8 GHz with a 16-MHz (2%) bandwidth for the first band and at 2.0 GHz with a 40-MHz (2%) bandwidth for the second band. A compact (30 mm × 28.25 mm) filter was fabricated using YBa2Cu3 Oy thin film on a CeO2-buffered Al2O3 substrate. The measured results agree well with the simulated ones.
Autors: Naoto Sekiya;
Appeared in: IEEE Transactions on Applied Superconductivity
Publication date: Jan 2017, volume: 27, issue:1, pages: 1 - 4
Publisher: IEEE
 
» Design of Financial Incentive ProgramsPub _newline to Promote Net Zero Energy Buildings
Abstract:
Promoting net zero energy buildings (NZEB) is among the key carbon emissions reduction approaches widely adopted by policymakers in recent years in the U.S. and the EU countries (see work of Marszal ). Due to the relatively higher cost of electricity generation from renewable energy (RE), federal, state, and local governments offer various financial incentive programs to promote NZEB. This paper presents a model-based framework for the policymakers to design suitable incentive programs. The model is a mixed integer program (MIP) that is particularized for wind and solar energy sources. The MIP model finds an optimal design for a NZEB. The optimal design and the cost of NZEB is then used to design incentive programs. The incentive programs considered includes loans, production tax credit, and net metering, among others. A time-of-day pricing is assumed to be in effect. The model is implemented on commercial buildings in Tampa, Florida, U.S.A. For a given region, the framework provides policymakers two reports, 1) a set of optimal portfolios of incentives for different classes of commercial buildings (based on credit rating, expected return on investment (ROI), and building type), 2) for a specified portfolio of incentives, determines which classes of commercial buildings will be willing to invest in RE.
Autors: Alireza Ghalebani;Tapas K. Das;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 75 - 84
Publisher: IEEE
 
» Design of Fixed-Frequency Pulsewidth-Modulation-Based Sliding-Mode Controllers for the Quadratic Boost Converter
Abstract:
The steady-state regulation error in power converters that use the pulsewidth-modulation (PWM)-based sliding-mode (SM) controllers can be alleviated via the use of a double-integral term of the state variables in the sliding surface. However, this not only increases the order of the controller but may also require more variables like two currents in feedback. Ideally, the controller should be of a lower order to reduce the cost and for ease of implementation. The main objective of this brief is to design a fixed-frequency PWM-based SM controller for the quadratic boost converter using a reduced number of state variables. The SM controller used in this brief requires only one current for its implementation while enjoying the advantages offered by both fixed-frequency and double-integral approaches. Apart from this, two SM controllers using the input and output inductor currents of the converter are separately designed to find the most suitable inductor current for the controller design. Such study is especially required for the higher order converters wherein more than one inductor currents are available for feedback purposes. It is shown that the controller using the input inductor current is preferred over the controller using the output inductor current. Some simulation and experimental results are also provided to validate the theoretical conclusions.
Autors: Satyajit Hemant Chincholkar;Chok-You Chan;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 51 - 55
Publisher: IEEE
 
» Design of High-Performance Filtering Balun Based on TE01δ-Mode Dielectric Resonator
Abstract:
This paper presents a fusion design approach of high-performance filtering balun based on the ring-shaped dielectric resonator (DR) for the first time. According to the electromagnetic (EM) field properties of the TE01δ mode of the DR cavity, it can be differentially driven or extracted by reasonably placing the orientations of the feeding probes, which answers for the realization of unbalanced-to-balanced conversion. As a result, the coupling between the resonators can refer to the traditional single-ended design, regardless of the feeding scheme. Based on this, a second-order DR filtering balun is designed by converting a four-port balanced filter to a three-port device. Within the passband, the excellent performance of amplitude balance and phase difference at the balun outputs can be achieved. To improve the stopband rejection by suppressing the spurious responses of the DR cavity, a third-order filtering balun using the hybrid DR and coaxial resonator is designed. It is not rigorously symmetrical, which is different from the traditional designs. The simulated and measured results with good accordance showcase good filter and balun functions at the same time.
Autors: Jian-Xin Chen;Yang Zhan;Wei Qin;Zhi-Hua Bao;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 451 - 458
Publisher: IEEE
 
» Design of low-margin optical networks
Abstract:
We review margins used in optical networks and review a formerly proposed margin taxonomy. For each category of margins, we review techniques that the network designer can use in order to increase the capacity of optical networks, extend their life, and decrease deployment cost (CAPEX) or total cost of ownership over their life duration. Green field (new network deployments) and brown field techniques (used after initial network deployment) are discussed. The technology needed to leverage the margins and achieve the aforementioned gains are also reviewed, along with the associated challenges.
Autors: Yvan Pointurier;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Jan 2017, volume: 9, issue:1, pages: A9 - A17
Publisher: IEEE
 
» Design of Simultaneous Wireless Information and Power Transfer Scheme for Short Reference DCSK Communication Systems
Abstract:
Recently, a short reference differential chaos shift keying system (SR-DCSK) has been proposed to overcome the dominant drawbacks related to low data rate and energy efficiency fondness of conventional DCSK systems. The fact that terminals on a network have a limited battery capacity and are in desperate need to high energy efficiency transmission schemes compels us to tackle these crucial challenges. In this paper, we propose an SR-DCSK system that performs simultaneous wireless information and power transfer (SWIPT). This promising design exploits the saved time gained from the fact that reference signal duration of SR-DCSK scheme occupies less than half of the bit duration to transmit a signal. The aim of this system is to allow receivers to perform without being equipped with any external power supply. Furthermore, at the receiver side, an RF-to-dc conversion is first performed, followed by data recovery without the need to any channel estimator. Closed-form expressions of multiple-input single-output SR-DCSK SWIPT system, such as ergodic rate, harvesting time, energy shortage, and data outage as well as exact and approximate bit error rate probabilities are derived under Rayleigh fading channel and are validated via simulation. Our results show that the proposed solution saves energy without sacrificing the non-coherent fashion of the system or reducing the rate compared to conventional DCSK, while keeping the design simple.
Autors: Georges Kaddoum;Ha-Vu Tran;Long Kong;Micheal Atallah;
Appeared in: IEEE Transactions on Communications
Publication date: Jan 2017, volume: 65, issue:1, pages: 431 - 443
Publisher: IEEE
 
» Detailed Excitation Control Methods for Two-Phase Brushless Exciter of the Wound-Rotor Synchronous Starter/Generator in the Starting Mode
Abstract:
An integrated starter/generator based on the wound-rotor synchronous machine is becoming increasingly popular in modern aircraft due to the advantages of high safety and low cost in maintenance. Constant field current for the main generator of the wound-rotor synchronous starter/generator (WRSSG) can simplify the start control scheme distinctly in the starting mode. In order to achieve constant field current for the main generator, three detailed excitation control methods for the two-phase brushless exciter of the WRSSG in the starting mode were proposed and compared in this paper. And in these excitation control methods, feedback control for the field currents of the two-phase brushless exciter and speed reference control for the excitation frequency and phase sequence were adopted. Simulation and experimental results verified the feasibility and effectiveness of these three excitation control methods.
Autors: Ningfei Jiao;Weiguo Liu;Tao Meng;Jichang Peng;Shuai Mao;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 115 - 123
Publisher: IEEE
 
» Detection Technique for Stator Inter-Turn Faults in BLDC Motors Based on Third-Harmonic Components of Line Currents
Abstract:
Among the methods for detecting stator inter-turn faults, the techniques that use the harmonic characteristics have been researched in induction motors with distributed windings. However, it is questionable that the techniques are available to apply in permanent magnet machines with concentrated windings and different control methods. First of all, this study analyzes the harmonic components of line current in a brushless dc (BLDC) motor, including the issues such as supply imbalance and inherent structural asymmetry, through the developed finite-element analysis and experiment under different operating conditions. As a result, the third harmonic in negative frequency (–3f) is suitable as a fault detector because it is free from those issues. Finally, in BLDC motors with 120° conduction in a six-step operation, the faults can be detected by determining whether or not the third harmonics exist at the incipient state.
Autors: Seung-Tae Lee;Jin Hur;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 143 - 150
Publisher: IEEE
 
» Deterministic Networked Control of Discrete Event Systems With Nondeterministic Communication Delays
Abstract:
We continue to investigate the impacts of communication delays on networked control of discrete event systems (DES). Our previous results show that nondeterministic communication delays result in nondeterminism in the languages generated by the controlled system, which makes the networked control problems more complex. In this paper we investigate the language nondeterminism. We define delay observability and delay controllability. If the language to be synthesized is delay observable and delay controllable, we can synthesize a networked supervisor to control the DES such that the language generated by the controlled system is deterministic, that is, we can synthesize a “deterministic” state-estimate-based networked supervisor. We derive algorithms to check delay controllability and delay observability. If the language to be synthesized is not delay observable and/or delay controllable, we can find its infimal delay controllable and delay observable superlanguage and maximal delay controllable and delay observable sublanguages. We develop algorithms to find these superlanguages and sublanguages. All the algorithms proposed in the paper are of polynomial computational complexity.
Autors: Shaolong Shu;Feng Lin;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 190 - 205
Publisher: IEEE
 
» Deterministic Pilot Design for Sparse Channel Estimation in MISO/Multi-User OFDM Systems
Abstract:
We study the pilot design problem for sparse channel estimation in OFDM systems where multiple channels are estimated at a single antenna receiver. Such design is applicable to downlink of massive-MIMO systems and also to scenarios where multiple users transmit to a base station at the same carrier frequency. In our design, we deviate from the conventional orthogonal pilot arrangements by assigning the same pilot subcarriers to all transmitters. In the proposed setting, the achieved improvement in spectral efficiency (by reducing pilot overhead) may come at the expense of a more challenging channel estimation block at the receiver. To address this challenge and distinguish between different signals that are arriving at the receiver at the same subcarrier, we propose to select pilot subcarriers through minimizing the coherence of the associated Fourier submatrix, as well as properly assigning different pilot values (complex numbers) to each individual transmitter. We demonstrate that if the channels are sparse enough in time domain, there are simple sparse recovery techniques to simultaneously estimate all the channels, although all transmitters share the same pilot subcarriers. Simulation results demonstrate that the proposed design outperforms existing methods in terms of both mean-square channel estimation error and bit error rate.
Autors: Roozbeh Mohammadian;Arash Amini;Babak Hossein Khalaj;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 129 - 140
Publisher: IEEE
 
» Development and Dynamic Characterization of a Mixed Mode Magnetorheological Elastomer Isolator
Abstract:
Magnetorheological elastomers (MREs) are a kind of smart material, whose mechanical properties are controllable with applied magnetic field. Moreover, there is a greater magnetorheological effect for MREs at small strain amplitude, which has attracted more attention in the field of microvibration control. In this paper, an MRE isolator with shear-compression mixed mode was developed to suppress the high-frequency and microamplitude vibration of a precision-fabrication platform. To evaluate and characterize the dynamic behavior of the MRE isolator, experiments were conducted under harmonic load and different magnetic fields, respectively. Experiments showed that the resonance frequency of the MRE isolation system shifted from 45.82 (0 A) to 82.55 Hz (1.5 A). Meanwhile, the relative change in equivalent stiffness and damping was 175% and 216%, respectively, and the relative change in isolator force was 190% from 0 to 1.5 A. The proposed mixed mode MRE isolator effectively isolated vibration at high frequency for microamplitude.
Autors: Jie Fu;Peidong Li;Guanyao Liao;Junjie Lai;Miao Yu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 4
Publisher: IEEE
 
» Development and Experimental Validation of a Non-Linear, All-Elastomer In-Plane Capacitive Pressure Sensor Model
Abstract:
A large deformation mechanics model is applied to predict capacitance changes in an all-elastomer capacitive tactile sensor, and the predictive model is experimentally validated. The compressive model predicts a non-linear relationship between the contact normal force and resulting capacitance change due to changes in electrode gap and electrode layer thickness. Broad parametric studies demonstrate that higher sensitivities can be achieved with lower modulus materials and smaller electrode gaps. Sensors are fabricated using a reusable silicon mold and experimental results are compared to predictions from the capacitance model. Capacitance-force model predictions yielded by the calibrated capacitance analytical model are shown to be in remarkable agreement with experimental measurements. A fringe effects term included in the capacitance model highlights the limitations of the parallel plate model especially for sensors with large electrode layer gaps.
Autors: Kourosh M. Kalayeh;Alexi Charalambides;Sarah Bergbreiter;Panos G. Charalambides;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 274 - 285
Publisher: IEEE
 
» Development of an automotive scanner for educational application
Abstract:
This paper deals with the strategy for development of an automotive scanner software for educational application, supplying the gaps created by the shortcomings of automotive electronics embedded systems diagnosis scanners market with respect to use in the classroom. The application of electronic diagnostic devices has become essential in view of the rapid development and growth of electronic embedded systems in automobiles, combined with increasing specialization necessary for professionals working in the maintenance segment and automotive repair. Using a low cost cable interface controller and application protocols established by the Society of Automotive Engineers (SAE), a Java PC application was developed. It allows the teacher to perform fault simulations without the need to modify parts or systems in the vehicle that is being used in class, ensuring greater productivity and safety in their classes.
Autors: Julio Camara Chaves;Valeria da Silva Loureiro;Tadeu Cerqueira Abreu;
Appeared in: IEEE Latin America Transactions
Publication date: Jan 2017, volume: 15, issue:1, pages: 40 - 47
Publisher: IEEE
 
» Development of Gasoline Direct Injector Using Giant Magnetostrictive Materials
Abstract:
This paper presents a conceptual design and control of a novel gasoline direct injector (GDI) using giant magnetostricitve material, Terfenol-D, as an actuation component. Electromagnetic and fluid analyses are accomplished to investigate the influence of some parameters, such as nozzle length, pressure of input fuel, and cone angle of injector's needle. Experimental results obtained from fabricated GDI show good agreement with the numerical results provided by the 3-D finite-element analysis. Furthermore, the fabricated GDI is controlled by fuzzy and PID controllers. It was shown that fuzzy controllers provide faster response with less accuracy compared to the PID controller. Consequently, there is a tradeoff between fast response and steady-state error for selecting the propoer controller.
Autors: Mojtaba Ghodsi;Nasser Hosseinzadeh;Abdullah Özer;Hamid Rajabzadeh Dizaj;Yousef Hojjat;Nader Garjasi Varzeghani;Mohammad Reza Sheykholeslami;Soheil Talebian;Mohammad Hadi Ghodsi;Amer Al-Yahmadi;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 521 - 529
Publisher: IEEE
 
» Device-to-Device Communication Underlaying a Finite Cellular Network Region
Abstract:
Underlay in-band device-to-device (D2D) communication can improve the spectrum efficiency of cellular networks. However, the coexistence of D2D and cellular users causes inter-cell and intra-cell interference. The former can be effectively managed through inter-cell interference coordination and, therefore, is not considered in this paper. Instead, we focus on the intra-cell interference and propose a D2D mode selection scheme to manage it inside a finite cellular network region. The potential D2D users are controlled by the base station (BS) to operate in D2D mode based on the average interference generated to the BS. Using stochastic geometry, we study the outage probability experienced at the BS and a D2D receiver, and spectrum reuse ratio, which quantifies the average fraction of successfully transmitting D2D users. The analysis shows that the outage probability at the D2D receiver varies for different locations. In addition, without impairing the performance at the BS, if the path-loss exponent on the cellular link is slightly lower than that on the D2D link, the spectrum reuse ratio can have negligible decrease, while the D2D users’ average number of successful transmissions increases with increasing D2D node density. This indicates that an increasing level of D2D communication can be beneficial in future networks.
Autors: Jing Guo;Salman Durrani;Xiangyun Zhou;Halim Yanikomeroglu;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 332 - 347
Publisher: IEEE
 
» Diamond Schottky Barrier Diodes With NO2 Exposed Surface and RF-DC Conversion Toward High Power Rectenna
Abstract:
A novel diamond Schottky barrier diode (SBD) with H-terminated surface exposed to NO2 gas is fabricated toward high power rectifying antenna (rectenna). The double NO2 exposures are introduced to provide high concentration of 2-D hole gas at the diamond surface. Experimentally, our SBDs have shown to give good rectifier properties with the high current density of 24 A/cm at a forward voltage of −2 V. A dual diode rectifier circuit using two diamond SBDs was designed with diode model constructed from experimental – curves. Values of circuit components such as dc block capacitance and load resistance were selected to achieve larger output voltage. Experimentally RF to dc conversion is demonstrated, where RF input voltage with 10 MHz and the amplitude of 9 V was converted into a dc output voltage as large as 4.2 V.
Autors: Toshiyuki Oishi;Naoto Kawano;Satoshi Masuya;Makoto Kasu;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 87 - 90
Publisher: IEEE
 
» Dielectric Response of Corn Leaves to Water Stress
Abstract:
Radar backscatter from a vegetated surface is sensitive to direct backscatter from the canopy and two-way attenuation of the signal as it travels through the canopy. Both mechanisms are affected by the dielectric properties of the individual elements of the canopy, which are primarily a function of water content. Leaf water content of corn can change considerably during the day and in response to water stress, and model simulations suggested that this significantly affects radar backscatter. Understanding the influence of water stress on leaf dielectric properties will give insight into how the plant water status changes in response to water stress and how radar can be used to detect vegetation water stress. We used a microstrip line resonator to monitor the changes in its resonant frequency at corn leaves, due to variations in dielectric properties. This letter presents the in vivo resonant frequency measurements during field experiments with and without water stress, to understand the dielectric response due to stress. The resonant frequency of the leaf around the main leaf of the stressed plant showed increasing diurnal differences. The dielectric response of the unstressed plant remained stable. This letter shows the clear statistically significant effect of water stress on variations in resonant frequency at individual leaves.
Autors: Tim Van Emmerik;Susan C. Steele-Dunne;Jasmeet Judge;Nick Van De Giesen;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 8 - 12
Publisher: IEEE
 
» Differential Chaos Shift Keying: A Robust Modulation Scheme for Power-Line Communications
Abstract:
The past few years have witnessed a tremendous development in power-line communications (PLCs) for the realization of smart grids. Since power lines were not originally intended for conveying high-frequency signals, any communication over these lines would be exposed to severe adversarial factors, such as interference, impulsive, and phase noise. This elucidates the importance of employing robust modulation techniques and motivates research in this direction. Indeed, the aim of this brief is to propose a differential chaos shift keying (DCSK) modulation scheme as a potential candidate for smart grid communication networks. This DCSK class of noncoherent modulation is very robust against linear and nonlinear channel distortions. More importantly, the demodulation process can be carried out without any channel estimator at the receiver side. In this work, we analyze the bit error rate performance of DCSK over multipath PLC channels in which phase, background, and impulsive noise are present. A simulator is developed to verify the performance of the proposed DCSK against direct sequence code division multiple access and direct sequence differential phase shift keying. The results presented in this work prove the advantages of this low-cost noncoherent modulation technique for PLC systems over its rivals.
Autors: Georges Kaddoum;Navid Tadayon;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 31 - 35
Publisher: IEEE
 
» Differential Lines for Common-Mode Suppression Based in Hybrid Microstrip/CPW Technology
Abstract:
A symmetrical pair of differential microstrip lines implemented in hybrid microstrip/coplanar waveguide (CPW) technology is proposed. Transmission-line models are used to analyze differential- and common-mode responses, allowing efficient design with minimal optimization effort. The structure behaves as a conventional transmission line pair under differential-mode excitation, whereas asymmetrical coupled transmission line theory has to be applied to characterize common-mode operation. The common mode is strongly suppressed thanks to the introduction of a controllable transmission zero. A two-stage version of the structure is used to increase the common-mode rejection bandwidth. All the electrical parameters of the transmission lines have been obtained using an in-house fast quasi-TEM code. The good agreement between transmission-line models, full-wave simulations and measurements confirms the benefits of the structure and the design procedure.
Autors: Jesús Martel;Armando Fernández-Prieto;Aintzane Lujambio;Francisco Medina;Francisco Mesa;Rafael R. Boix;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 13 - 15
Publisher: IEEE
 
» Differential Orthogonal Space-Time Block Coding Modulation for Time-Variant Underwater Acoustic Channels
Abstract:
Reliable underwater acoustic (UWA) communications are challenging since the channels are well known to be doubly selective in both time and frequency domains. The doubly-selective fading UWA channels, however, also provide double diversity gains. In addition, multiple transducers and/or hydrophones are often deployed, providing space diversity to combat channel fading. To exploit all these diversities, a differential multiple-input–multiple-output (MIMO) scheme for doubly-selective fading channels is presented in this paper. The proposed differential orthogonal space-time block coding (DOSTBC) approach adopts the basis expansion model (BEM) to capture the channel variation in time domain. Both analytical and simulated results show that the proposed BEM–DOSTBC approach is reliable by collecting 3-D diversity: space, multipath, and Doppler. The proposed approach was tested during the RACE08 sea experiment and its reliability was confirmed by the experiment results.
Autors: Fengzhong Qu;Zhenduo Wang;Liuqing Yang;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 188 - 198
Publisher: IEEE
 
» Differentially Private Distributed Constrained Optimization
Abstract:
Many resource allocation problems can be formulated as an optimization problem whose constraints contain sensitive information about participating users. This paper concerns a class of resource allocation problems whose objective function depends on the aggregate allocation (i.e., the sum of individual allocations); in particular, we investigate distributed algorithmic solutions that preserve the privacy of participating users. Without privacy considerations, existing distributed algorithms normally consist of a central entity computing and broadcasting certain public coordination signals to participating users. However, the coordination signals often depend on user information, so that an adversary who has access to the coordination signals can potentially decode information on individual users and put user privacy at risk. We present a distributed optimization algorithm that preserves differential privacy, which is a strong notion that guarantees user privacy regardless of any auxiliary information an adversary may have. The algorithm achieves privacy by perturbing the public signals with additive noise, whose magnitude is determined by the sensitivity of the projection operation onto user-specified constraints. By viewing the differentially private algorithm as an implementation of stochastic gradient descent, we are able to derive a bound for the suboptimality of the algorithm. We illustrate the implementation of our algorithm via a case study of electric vehicle charging. Specifically, we derive the sensitivity and present numerical simulations for the algorithm. Through numerical simulations, we are able to investigate various aspects of the algorithm when being used in practice, including the choice of step size, number of iterations, and the trade-off between privacy level and suboptimality.
Autors: Shuo Han;Ufuk Topcu;George J. Pappas;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 50 - 64
Publisher: IEEE
 
» Differentiating Tree and Shrub LAI in a Mixed Forest With ICESat/GLAS Spaceborne LiDAR
Abstract:
Leaf area index (LAI) is an important descriptor of many biological and physical processes of vegetation. However, the challenges associated with differentiating tree and shrub LAI (tsLAI) have hindered research in mixed forests. Being the first spaceborne LiDAR system, geoscience laser altimeter system (GLAS) has demonstrated its advantage in collecting extensive forest structure information. In this study, we aimed to estimate tsLAI in a mixed forest with GLAS. The refined Levenberg–Marquardt algorithm for Gaussian decomposition was implemented to decompose GLAS data into ground and multiple vegetation signals, within which it is hypothesized that each vegetation signal corresponds to a particular height layer. Subsequently, the height of each layer was extracted through the decomposed GLAS signals, and a height threshold method to distinguish trees from shrubs was developed. Then, a tsLAI-specific ratio defined as ground-to-total energy return of the GLAS signal was calculated, and tsLAI was predicted by a linear regression model established from field measurements and the ratio. Finally, a study site in Ejina, China, where the dominant species are Populus euphratica (tree) and Tamarix ramosissima (shrub) was used to calibrate and validate the methods. Compared with the field measurement LAI, GLAS-predicted LAI presented a high agreement in which R2 , RMSE, and %RMSE of trees were determined to be 0.797, 0.087, and 19.176, respectively. In contrast, R2 , RMSE, and %RMSE of shrubs were found to be 0.676, 0.081, and 21.825, respectively. Overall, our study provided a feasible and effective approach for estimating tsLAI with GLAS over a flat region.
Autors: Jinyan Tian;Le Wang;Xiaojuan Li;Chen Shi;Huili Gong;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 87 - 94
Publisher: IEEE
 
» Diffuse Vacuum Arc on the Nonthermionic Lead Cathode
Abstract:
Experimental study of the diffuse vacuum arc discharge on the nonthermionic lead cathode is presented. At the working cathode temperatures of 1.2–1.6-kK current–voltage characteristic of the discharge, cathode heat operation regime and its erosion rate were measured. Using probe methods, electron temperature (0.3–1.2 eV) and heavy particles (atoms and ions) mean charge (0.17–0.28 e) were determined in after-anode plasma. Evaluated current densities on the cathode are in agreement with a hypothesis on the ion mechanism of charge transfer on its surface. Parameters of the obtained discharge have been compared with the characteristics of the earlier investigated diffuse vacuum arcs on nonthermionic chromium and on thermionic gadolinium cathodes. The obtained data might be useful when creating plasma sources for verifying the plasma separation method of the spent nuclear fuel using the nonradioactive substances.
Autors: Ravil Kh. Amirov;Andrey V. Gavrikov;Gennadii D. Liziakin;Vladimir P. Polistchook Polishchuk;Igor S. Samoylov;Valentin P. Smirnov;Ravil A. Usmanov;Nazar A. Vorona;Ivan M. Yartsev;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jan 2017, volume: 45, issue:1, pages: 140 - 147
Publisher: IEEE
 
» Digital Noninverting-Buck–Boost Converter With Enhanced Duty-Cycle-Overlap Control
Abstract:
The nonideal effects of the comparator and dead time in a synchronous controlled dc-dc converter adversely affect the stability of a four-switch noninverting-buck–boost (NIBB) converter. The pulse-skipping phenomenon occurs in the mode-transition region near the boundary between the step-down and step-up regions, and this phenomenon leads to an unstable output voltage and an unpredictable output voltage ripple. However, these two results may damage the entire power system and application system. This brief proposes an enhanced duty-cycle-overlap control technique for a digitally controlled NIBB converter. The proposed technique offers two duty cycle limitations for various conditions in the mode-transition region and ensures the stability of the digital controller and output voltage. Moreover, this technique involves combining the duty cycles of both step-down and step-up modes for deriving an accurate value of the output voltage. The experimental results derived from a digital controller implemented through a field-programmable-gate-array-based platform revealed that the output voltage of the NIBB converter was stable throughout the transition region. The observed input voltage of the converter, provided by a Li-ion battery, was 2.5–4.5 V, and the output voltage was typically 3.3 V, which is suitable for communication systems, audio systems, and I/O pad power supplies. The switching frequency was 1 MHz, and the maximum load current was 500 mA.
Autors: Yi-Yang Tsai;Yu-Shin Tsai;Chien-Wu Tsai;Chien-Hung Tsai;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 41 - 45
Publisher: IEEE
 
» Digital Predistortion for Joint Mitigation of I/Q Imbalance and MIMO Power Amplifier Distortion
Abstract:
This paper analyzes the joint effects of in-phase and quadrature (I/Q) imbalance and power amplifier (PA) distortion for RF multiple input multiple output (MIMO) transmitters in the presence of crosstalk. This paper proposes candidate models for the digital predistortion of static I/Q imbalanced sources exciting a dynamic MIMO Volterra system. The proposed models are enhanced using a novel technique based on subsample resolution to account for dynamic I/Q imbalance distortions. Finally, the computational complexity of the proposed models is analyzed for implementation suitability in digital platforms. It is shown that the error spectrum for the proposed models in subsample resolution reaches the noise floor of the measurements. The proposed models achieve a normalized mean squared error of −50 dB and an adjacent channel power ratio of −57 dB for signal bandwidths upto 65 MHz and crosstalk levels ranging to −10 dB. These results demonstrate the effectiveness of the proposed techniques in the joint mitigation of I/Q imbalance and PA distortion with crosstalk for a typical MIMO telecommunication setup.
Autors: Zain Ahmed Khan;Efrain Zenteno;Peter Händel;Magnus Isaksson;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jan 2017, volume: 65, issue:1, pages: 322 - 333
Publisher: IEEE
 
» Direct Control of the Inverter Impedance to Achieve Controllable Harmonic Sharing in the Islanded Microgrid
Abstract:
Harmonic current sharing is an important aspect of islanded microgrid due to the presence of nonlinear loads. The existing harmonic current sharing strategies suggest a tradeoff between voltage quality and harmonic sharing effectiveness. In this paper, a novel control strategy is proposed to achieve current harmonic sharing by directly controlling the inherent impedance of the inverter. The proposed technique achieves harmonic sharing, in a distributed generation (DG)-based islanded microgrid, without using any communication infrastructure. This paper also proposes a droop technique to distribute the harmonics generated by the nonlinear load as per the kVA ratings of different DG units in the system. The proposed concept of variable inverter impedance and its application in an islanded microgrid is validated using experimental studies.
Autors: Preetha Sreekumar;Vinod Khadkikar;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 827 - 837
Publisher: IEEE
 
» Direct Integration 3-D FDTD Method for Single-Species Cold Magnetized Plasma
Abstract:
Finite-difference equations for 3-D single-species cold magnetized plasma EM propagation are systematically generated using a new, algorithmic approach for generating finite-difference time-domain (FDTD) updates. This new approach is then generalized to handle systems with complex dispersion of arbitrarily high-order. It is shown how this results in the second-order accurate algorithms with numerical dispersion relations that can always be cast in the form of continuum dispersion counterparts via simple substitutions, avoiding laborious analysis. This allowed here the first reporting of a numerical Appleton–Hartree equation. The problem of field collocation is handled by the repetition of the Yee algorithm so that all field variables are defined at the corners of a new cubic computational cell. This cell offers new properties, such as full-vector control of the solution at each node. A new technique for deriving the stability condition is introduced to FDTD and shows that the new method has retained the same stability criterion of free-space propagation. Several simulation results are presented, one of which reveals a previously unreported problem, common to some gyrotropic methods—the tendency for spurious fields to arise at source locations. It is shown how this spuriousness, which has contaminated the results of a previous report, may be removed.
Autors: Eric Gamliel;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 295 - 308
Publisher: IEEE
 
» Direct Modulation of a Laser Using 112-Gb/s 16-QAM Nyquist Subcarrier Modulation
Abstract:
A 112-Gb/s single-carrier, single-polarization short reach transmission system using a high bandwidth 1310 nm directly modulated laser is demonstrated. Spectrally efficient signal generation is achieved by using: 1) half-cycle Nyquist subcarrier modulation with 16-ary quadrature-amplitude-modulation; 2) pre-compensation for the frequency response of the end-to-end system; and 3) and a Volterra nonlinear equalizer to post-compensate for the nonlinear modulation dynamics of the laser. Digital signal processing techniques for signal recovery enable transmission over 20 km of standard single mode fiber with a bit error ratio below the 7% overhead hard-decision forward error correction coding threshold of at a received optical power of −5.25 dBm.
Autors: Yuliang Gao;John C. Cartledge;Aazar S. Kashi;Scott S.-H. Yam;Yasuhiro Matsui;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 35 - 38
Publisher: IEEE
 
» Direct Parametric Reconstruction With Joint Motion Estimation/Correction for Dynamic Brain PET Data
Abstract:
Direct reconstruction of parametric images from raw photon counts has been shown to improve the quantitative analysis of dynamic positron emission tomography (PET) data. However it suffers from subject motion which is inevitable during the typical acquisition time of 1–2 hours. In this work we propose a framework to jointly estimate subject head motion and reconstruct the motion-corrected parametric images directly from raw PET data, so that the effects of distorted tissue-to-voxel mapping due to subject motion can be reduced in reconstructing the parametric images with motion-compensated attenuation correction and spatially aligned temporal PET data. The proposed approach is formulated within the maximum likelihood framework, and efficient solutions are derived for estimating subject motion and kinetic parameters from raw PET photon count data. Results from evaluations on simulated [11C]raclopride data using the Zubal brain phantom and real clinical [18F]florbetapir data of a patient with Alzheimer’s disease show that the proposed joint direct parametric reconstruction motion correction approach can improve the accuracy of quantifying dynamic PET data with large subject motion.
Autors: Jieqing Jiao;Alexandre Bousse;Kris Thielemans;Ninon Burgos;Philip S. J. Weston;Jonathan M. Schott;David Atkinson;Simon R. Arridge;Brian F. Hutton;Pawel Markiewicz;Sébastien Ourselin;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 203 - 213
Publisher: IEEE
 
» Direction-of-Arrival Estimation and Sensor Array Error Calibration Based on Blind Signal Separation
Abstract:
We consider estimating the direction-of-arrival (DOA) in the presence of sensor array error. In the proposed method, a blind signal separation method, the joint approximation and diagonalization of eigenmatrices algorithm, is implemented to separate the signal vector and the mixing matrix consisting of the array manifold matrix and the sensor array error matrix. Based on a new mixing matrix and the reconstruction of the array output vector of each individual signal, we propose a novel DOA estimation and sensor array error calibration procedure. This method is independent of array phase errors and performs well against difference of SNR of signals. Numerical simulations verify the effectiveness of the proposed method.
Autors: Jianfei Liu;Xiongbin Wu;William J. Emery;Lan Zhang;Chuan Li;Ketao Ma;
Appeared in: IEEE Signal Processing Letters
Publication date: Jan 2017, volume: 24, issue:1, pages: 7 - 11
Publisher: IEEE
 
» Directional Full-Duplex RF Booster for 2450 MHz ISM Band
Abstract:
A directional repeater system with simple architecture composed of wideband receive and transmit antennas, a high gain low-power amplifier, and a bandpass filter is proposed for the 2450-MHz ISM band. The repeater system does not require down-conversion and up-conversion with frequency translation and does not rely on any operational protocol to manage users. As a result, the repeater (RF booster) can support all users, channels, modulation themes, and devices simultaneously. Close to 70 dB of isolation between the Tx and Rx antennas over the entire band (~100 MHz) is achieved for a compact structure with lateral dimensions of 8 cm 12 cm and thickness of 1 cm. The isolation between the Tx and Rx antennas is achieved using polarization mismatch between orthogonal double-stack patch antennas and a novel two-element Rx antenna whose elements are appropriately located with respect to the Tx antenna to cancel the signal leakage from the Tx antenna to the Rx antennas. Two types of repeaters, one utilizing only the ground plane and polarization mismatch, and the second using the two-element Rx antenna in addition to polarization mismatch, are fabricated and tested in different environments. It is shown that more than 30 dB improvement in coverage can be achieved.
Autors: Mani Kashanianfard;Kamal Sarabandi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 134 - 141
Publisher: IEEE
 
» Directional Kernel Density Estimation for Classification of Breast Tissue Spectra
Abstract:
In Breast Conserving Therapy, surgeons measure the thickness of healthy tissue surrounding an excised tumor (surgical margin) via post-operative histological or visual assessment tests that, for lack of enough standardization and reliability, have recurrence rates in the order of 33%. Spectroscopic interrogation of these margins is possible during surgery, but algorithms are needed for parametric or dimension reduction processing. One methodology for tumor discrimination based on dimensionality reduction and nonparametric estimation—in particular, Directional Kernel Density Estimation—is proposed and tested on spectral image data from breast samples. Once a hyperspectral image of the tumor has been captured, a surgeon assists by establishing Regions of Interest where tissues are qualitatively differentiable. After proper normalization, Directional KDE is used to estimate the likelihood of every pixel in the image belonging to each specified tissue class. This information is enough to yield, in almost real time and with 98% accuracy, results that coincide with those provided by histological H&E validation performed after the surgery.
Autors: Arturo Pardo;Eusebio Real;Venkat Krishnaswamy;José Miguel López-Higuera;Brian W. Pogue;Olga M. Conde;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 64 - 73
Publisher: IEEE
 
» Dirichlet Process Gaussian Mixture Models for Real-Time Monitoring and Their Application to Chemical Mechanical Planarization
Abstract:
The goal of this work is to use sensor data for online detection and identification of process anomalies (faults). In pursuit of this goal, we propose Dirichlet process Gaussian mixture (DPGM) models. The proposed DPGM models have two novel outcomes: 1) DP-based statistical process control (SPC) chart for anomaly detection and 2) unsupervised recurrent hierarchical DP clustering model for identification of specific process anomalies. The presented DPGM models are validated using numerical simulation studies as well as wireless vibration signals acquired from an experimental semiconductor chemical mechanical planarization (CMP) test bed. Through these numerically simulated and experimental sensor data, we test the hypotheses that DPGM models have significantly lower detection delays compared with SPC charts in terms of the average run length (ARL1) and higher defect identification accuracies (F-score) than popular clustering techniques, such as mean shift. For instance, the DP-based SPC chart detects pad wear anomaly in CMP within 50 ms, as opposed to over 140 ms with conventional control charts. Likewise, DPGM models are able to classify different anomalies in CMP.
Autors: Jia Peter Liu;Omer F. Beyca;Prahalad K. Rao;Zhenyu James Kong;Satish T. S. Bukkapatnam;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 208 - 221
Publisher: IEEE
 
» Disclosure of Double Exchange Bias Effect in Chromium (III) Oxide Nanoparticles
Abstract:
In the last decade, the renewed interest in antiferromagnetic (AF) magnetoelectric (ME) materials has been driven by the challenging multifunctionality of spintronic devices. One of the most ambitious goals is to build exchange-biased ferromagnetic/AF junctions with electric field-controlled properties. In this context, the understanding of the modifications that size reduction induces in the magnetic properties of a material being both AF and ME holds the key to control the magnetic coupling at the interface. Here, we show that the spin arrangement in chromium (III) oxide core/shell nanoparticles changes significantly as a function of the radial distance from the nanoparticle center. While the nanoparticle core retains an AF structure, magnetic moments located on a thin surface shell are in a disordered spin-glass (SG)-like state. In addition, canted spins develop at the boundary of the ME AF core. These spins, which mediate a moderate AF/SG exchange coupling at low temperature, are exchange coupled to the AF core, thus giving rise to a lower yet more robust exchange bias effect, which persists up to the Néel temperature of the AF core.
Autors: Natalia Rinaldi-Montes;Pedro Gorria;Antonio B. Fuertes;David Martínez-Blanco;Luca Olivi;Inés Puente-Orench;Javier Alonso;Manh-Huong Phan;Hariharan Srikanth;Xavi Marti;Jesús A. Blanco;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 4
Publisher: IEEE
 
» Discovering New Worlds: A review of signal processing methods for detecting exoplanets from astronomical radial velocity data [Applications Corner]
Abstract:
Exoplanets, short for extra solar planets, are planets outside our solar system. They are objects with masses fewer than around 15 Jupiter-masses that orbit stars other than the sun. They are small enough so they cannot burn deuterium in their cores, yet large enough that they are not so-called dwarf planets like Pluto.
Autors: Muhammad Salman Khan;James Jenkins;Nestor Becerra Yoma;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 104 - 115
Publisher: IEEE
 
» Discretization-Based and Look-Ahead Algorithms for the Dubins Traveling Salesperson Problem
Abstract:
A new class of discretization-based look-ahead algorithms (DLAAs) for the Dubins traveling salesperson problem (DTSP) is presented that compares favorably with the existing algorithms from the literature. The discretization level and the length of the look-ahead horizon are the two parameters that uniquely determine a DLAA, and depending on the application in hand, their values can be easily modified to strike a balance between the execution time and the length of the resulting admissible tour. The time complexity of a DLAA is the sum of two terms, one linear in the number of targets (cities) and one that corresponds to the specification of an initial order for the targets. For instances of the DTSP with densely distributed targets, an algorithm that relies on clustering and leads to shorter tours than the DLAA is also presented.
Autors: Izack Cohen;Chen Epstein;Pantelis Isaiah;Saar Kuzi;Tal Shima;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 383 - 390
Publisher: IEEE
 
» Discriminative and Efficient Label Propagation on Complementary Graphs for Multi-Object Tracking
Abstract:
Given a set of detections, detected at each time instant independently, we investigate how to associate them across time. This is done by propagating labels on a set of graphs, each graph capturing how either the spatio-temporal or the appearance cues promote the assignment of identical or distinct labels to a pair of detections. The graph construction is motivated by a locally linear embedding of the detection features. Interestingly, the neighborhood of a node in appearance graph is defined to include all the nodes for which the appearance feature is available (even if they are temporally distant). This gives our framework the uncommon ability to exploit the appearance features that are available only sporadically. Once the graphs have been defined, multi-object tracking is formulated as the problem of finding a label assignment that is consistent with the constraints captured each graph, which results into a difference of convex (DC) program. We propose to decompose the global objective function into node-wise sub-problems. This not only allows a computationally efficient solution, but also supports an incremental and scalable construction of the graph, thereby making the framework applicable to large graphs and practical tracking scenarios. Moreover, it opens the possibility of parallel implementation.
Autors: Amit Kumar K.C.;Laurent Jacques;Christophe De Vleeschouwer;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2017, volume: 39, issue:1, pages: 61 - 74
Publisher: IEEE
 
» Dissecting GPU Memory Hierarchy Through Microbenchmarking
Abstract:
Memory access efficiency is a key factor in fully utilizing the computational power of graphics processing units (GPUs). However, many details of the GPU memory hierarchy are not released by GPU vendors. In this paper, we propose a novel fine-grained microbenchmarking approach and apply it to three generations of NVIDIA GPUs, namely Fermi, Kepler, and Maxwell, to expose the previously unknown characteristics of their memory hierarchies. Specifically, we investigate the structures of different GPU cache systems, such as the data cache, the texture cache and the translation look-aside buffer (TLB). We also investigate the throughput and access latency of GPU global memory and shared memory. Our microbenchmark results offer a better understanding of the mysterious GPU memory hierarchy, which will facilitate the software optimization and modelling of GPU architectures. To the best of our knowledge, this is the first study to reveal the cache properties of Kepler and Maxwell GPUs, and the superiority of Maxwell in shared memory performance under bank conflict.
Autors: Xinxin Mei;Xiaowen Chu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jan 2017, volume: 28, issue:1, pages: 72 - 86
Publisher: IEEE
 
» Dissipativity for a Class of Stochastic Nonlinear Systems With State-Dependent Switching
Abstract:
Dissipativity of stochastic nonlinear systems with state-dependent switching is investigated in this brief. Switching instants are introduced reasonably, based on the evolution of the state trajectory, which are proved to be stopping times. They are the key to apply Itô’s formula and Dynkin’s formula in stochastic systems. Based on these stopping times, some sufficient conditions on dissipativity of switched stochastic systems are provided. Furthermore, the criteria on global asymptotic stability and input-to-state stability in probability are presented by using a common Lyapunov function technique and multiple Lyapunov functions techniques, respectively. Finally, a numerical example is given to illustrate the validity of our results.
Autors: Dianfeng Zhang;Xi-Ming Sun;Zhaojing Wu;Wei Wang;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 86 - 90
Publisher: IEEE
 
» Distance-Based Cycle-Free Persistent Formation: Global Convergence and Experimental Test With a Group of Quadcopters
Abstract:
In this paper, distributed formation control for multi-agent systems is considered. The proposed control laws are designed to globally obtain and keep the desired formation in a two-dimensional space. It is assumed that the local frames of the agents are not aligned with each other and each agent does not know the orientation of others’ coordinate frames. Further, the agent measures only relative positions of neighbors with respect to the local reference frame. Therefore, the control of the system is completely decentralized and the global convergence is achieved without the global reference frame. The stability and convergence of the system are analyzed mathematically and the experiment using quadcopters is performed to verify the results of the theoretical analysis. In addition, the ambiguity problem and time-varying velocity case are also handled and discussed.
Autors: Sung-Mo Kang;Myoung-Chul Park;Hyo-Sung Ahn;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 380 - 389
Publisher: IEEE
 
» Distinguishing Heavy-Metal Stress Levels in Rice Using Synthetic Spectral Index Responses to Physiological Function Variations
Abstract:
Accurately assessing the heavy-metal contamination in crops is crucial to food security. This study provides a method to distinguish heavy-metal stress levels in rice using the variations of two physiological functions as discrimination indices, which are obtained by assimilation of remotely sensed data with a crop growth model. Two stress indices, which correspond to daily total assimilation and dry-matter conversion coefficient were incorporated into the World Food Study (WOFOST) crop growth model and calculated by assimilating the model with leaf area index (LAI), which was derived from time-series HJ1-CCD data. The stress levels are not constant with rice growth; thus, to improve the reliability, the two stress indices were obtained at both the first and the latter half periods of rice growth. To compare the stress indices of different stress levels, a synthetic stress index was established by combining the two indices; then, three types of stress index discriminant spaces based on the synthetic index of different growth periods were constructed, in which the two-dimensional discriminant space based on two growth periods showed the highest accuracy, with a misjudgment rate of 4.5%. When the discrimination rules were applied at a regional scale, the average correct discrimination rate was 95.0%.
Autors: Ming Jin;Xiangnan Liu;Ling Wu;Meiling Liu;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 75 - 86
Publisher: IEEE
 
» Distortion Magnetic Field Compensation of Geomagnetic Vector Measurement System Using a 3-D Helmholtz Coil
Abstract:
The magnetic interferential fields, such as soft-iron and hard-iron interferences, will seriously affect the accuracy of geomagnetic vector measurement system, and thus should be compensated. In this letter, a new compensation method using a 3-D Helmholtz coil is proposed. As a first step, the geomagnetic vector measurement system is exposed to different directions and the magnitudes of magnetic field generated by a 3-D Helmholtz coil to construct the equations of error model, and soft-iron parameters can be estimated by solving linear equations. Then, hard-iron parameters are estimated by changing the fixation direction of the three-axis magnetometer. Finally, all the estimated parameters are used for compensating distortion magnetic fields. In order to verify the effectiveness of the proposed method, the experiment is conducted, and the results demonstrate that the proposed method contributes to the accuracy improvement of geomagnetic vector measurement system.
Autors: Zhongyan Liu;Qi Zhang;Mengchun Pan;Qingxiao Shan;Yunling Geng;Feng Guan;Dixiang Chen;Wugang Tian;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 48 - 51
Publisher: IEEE
 
» Distributed Channel Access for Device-to-Device Communications: A Hypergraph-Based Learning Solution
Abstract:
In this letter, we propose a learning solution for distributed channel access in device-to-device communications based on a hypergraph interference model. We first define a new interference metric for a hypergraph model, and then formulate this distributed channel access problem as a local altruistic game, which is proved to be an exact potential game admitting at least one pure strategy Nash equilibrium (PNE). A distributed learning algorithm is designed to quickly achieve the optimal PNE, which can minimize the defined networks’ interference metric. Simulation results show that the proposed algorithm outperforms the existing schemes and significantly improves the spectrum efficiency.
Autors: Youming Sun;Qihui Wu;Yuhua Xu;Yuli Zhang;Fenggang Sun;Jinlong Wang;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 180 - 183
Publisher: IEEE
 
» Distributed Energy-Efficient Cross-Layer Optimization for Multihop MIMO Cognitive Radio Networks With Primary User Rate Protection
Abstract:
Due to the unique physical-layer characteristics associated with multiple-input multiple-output (MIMO) and cognitive radio (CR), the network performance is tightly coupled with mechanisms at the physical, link, network, and transport layers. In this paper, we consider an energy-efficient cross-layer optimization problem in multihop MIMO CR networks (CRNs) and provide a new formulation to balance the weighted network utility and the weighted power consumption of secondary users (SUs), with the minimum transmission rate constraint of primary users (PUs) and the SU power consumption constraint. However, this formulation is highly challenging due to the nonconvexity of the PU rate constraint. We propose a solution that features a linearization-based alternative optimization method and a heuristic primal recovery method. We further develop a distributed algorithm to jointly optimize the covariance matrix of the transmitted signal vector at each SU node, bandwidth allocation at each SU link, rate control at each session source, and multihop/multipath routing. Extensive simulation results demonstrate that the performance of the proposed distributed algorithm is very close to that of the centralized algorithm, and the proposed formulation provides an efficient way to save power consumption significantly, while achieving the network utility very close to that achieved with full power consumption.
Autors: Weiqiang Xu;Wenchu Yuan;Qingjiang Shi;Xiaodong Wang;Yake Zhang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 785 - 797
Publisher: IEEE
 
» Distributed Energy-Saving Cellular Network Management Using Message-Passing
Abstract:
This paper presents a distributed energy-saving management strategy for green cellular networks. During off-peak periods, an energy-saving operation is activated. A subset of base stations (BSs) in the network enters an energy-saving state, i.e., switched-off mode, while satisfying traffic demands without discontinuity of user services. To this end, the remaining operating BSs should compensate for the coverage holes by taking over the responsibility of user service. Such a scenario can be formulated into a combinatorial optimization that maximizes the overall energy savings of the network. To address this computationally demanding task, we develop a distributed algorithm that provides an efficient solution by using a state-of-the-art technique based on a message-passing framework. The simulation results confirm considerable energy-saving gains over previously existing techniques and prove the viability for this strategy for self-organizing green cellular networks.
Autors: Sang Hyun Lee;Illsoo Sohn;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 635 - 644
Publisher: IEEE
 
» Distributed Evaluation and Convergence of Self-Appraisals in Social Networks
Abstract:
We consider in this paper a networked system of opinion dynamics in continuous time, where the agents are able to evaluate their self-appraisals in a distributed way. In the model we formulate, the underlying network topology is described by a rooted digraph. For each ordered pair of agents , we assign a function of self-appraisal to agent , which measures the level of importance of agent to agent . Thus, by communicating only with her neighbors, each agent is able to calculate the difference between her level of importance to others and others' level of importance to her. The dynamical system of self-appraisals is then designed to drive these differences to zero. We show that for almost all initial conditions, the trajectory generated by this dynamical system asymptotically converges to an equilibrium point which is exponentially stable.
Autors: Xudong Chen;Ji Liu;Mohamed-Ali Belabbas;Zhi Xu;Tamer Başar;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 291 - 304
Publisher: IEEE
 
» Distributed Frequency Control Through MTDC Transmission Systems
Abstract:
In this paper, we propose distributed dynamic controllers for sharing both frequency containment and restoration reserves of asynchronous ac systems connected through a multi-terminal HVDC (MTDC) grid. The communication structure of the controller is distributed in the sense that only local and neighboring state information is needed, rather than the complete state. We derive sufficient stability conditions, which guarantee that the ac frequencies converge to the nominal frequency. Simultaneously, a global quadratic power generation cost function is minimized. The proposed controller also regulates the voltages of the MTDC grid, asymptotically minimizing a quadratic cost function of the deviations from the nominal dc voltages. The results are valid for distributed cable models of the HVDC grid (e.g., -links), as well as ac systems of arbitrary number of synchronous machines, each modeled by the swing equation. We also propose a decentralized communication-free version of the controller. The proposed controllers are tested on a high-order dynamic model of a power system consisting of asynchronous ac grids, modeled as IEEE 14 bus networks, connected through a six-terminal HVDC grid. The performance of the controller is successfully evaluated through simulation.
Autors: Martin Andreasson;Roger Wiget;Dimos V. Dimarogonas;Karl H. Johansson;Göran Andersson;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 250 - 260
Publisher: IEEE
 
» Distributed Generation Control Method for Active Power Sharing and Self-Frequency Recovery in an Islanded Microgrid
Abstract:
This paper describes a control method for distributed generation (DG) units to implement active power sharing and frequency recovery simultaneously in an islanded microgrid. Conventional active power–frequency (P f) droop control is used for the DG controller, and the frequency deviation is recovered by the DG itself via self-frequency recovery control, without requiring secondary frequency control. Because the electrical distance (impedance) from each DG unit to a point where the load demand changes differs among DG units, the instantaneous frequency deviations may differ between DG units. These differences are fed into the integrators of the self-frequency recovery control and may result in errors in active power sharing. To solve this problem and share active power more accurately, a compensation control method is developed for active power sharing, which considers the droop coefficients of each of the DG units. Simulation results show that the proposed control method is effective.
Autors: Yun-Su Kim;Eung-Sang Kim;Seung-Il Moon;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 544 - 551
Publisher: IEEE
 
» Distributed Linear Constellation Precoding With BICM/BICM-ID in Two-Way Relaying Communications
Abstract:
This paper investigates distributed linear constellation precoding (DLCP) for two-way relaying communication systems in conjunction with the techniques of bit-interleaved coded modulation (BICM) and BICM with iterative decoding (BICM-ID). First, a decoding strategy for the relay node that is based on quaternary code representation is developed. Then, the union bounds (for the case of BICM) and error-free feedback bounds (for the case of BICM-ID) on the quaternary digit error probability and bit error probability under network coding in the multiple-access (MA) phase are obtained. Based on the obtained bounds, the impact of DLCP on the error performance is analyzed by considering three error types in the MA phase. It is shown that type-3 errors need to be carefully taken into account in the design of a DLCP scheme. By developing a performance metric related to type-3 errors, the design parameter of DLCP is optimized when BICM is used, whereas it is shown that DLCP is not needed when BICM-ID is used. Extensive simulation results are provided to corroborate the analysis and demonstrate the performance superiority of the proposed decoding strategy over the one that directly decodes the exclusive-OR (xor) code. For the case of BICM, the performance advantage achieved by properly designing DLCP is also illustrated.
Autors: Hongzhong Yan;Ha H. Nguyen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 481 - 493
Publisher: IEEE
 
» Distributed MIMO Broadcasting: Reverse Compute-and-Forward and Signal-Space Alignment
Abstract:
We study a downlink distributed MIMO system where a central unit (CU) broadcasts messages to users through distributed BSs. The CU is connected to the BSs via independent rate-constrained fronthaul (FH) links. The distributed BSs collectively serve the users through the air. We propose a new network coding based distributed MIMO broadcasting scheme, using reverse compute-and-forward and signal-space alignment. At the CU, a network coding generator matrix is employed for pre network coding of the users’ messages. The network coded messages are forwarded to the BSs, where the FH rate-constraint determines the actual number of network-coded messages forwarded to the BSs. At the BSs, linear precoding matrices are designed to create a number of bins, each containing a bunch of spatial streams with aligned signal-spaces. At each user, post physical-layer network coding is employed to compute linear combinations over the NC messages with respect to the bins, which reverses the prenetwork coding and recovers the desired messages. We derive an achievable rate of the proposed scheme based on the existence of NC generator matrix, signal-space alignment precoding matrices, and nested lattice codes. Improved rate and degrees of freedom over existing interference alignment and compress-and-forward schemes are shown. Numerical results demonstrate the performance improvement, e.g., by as much as 70% increase in throughput over benchmark schemes.
Autors: Tao Yang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 581 - 593
Publisher: IEEE
 
» Distributed MIMO Multicast With Protected Receivers: A Scalable Algorithm for Joint Beamforming and Nullforming
Abstract:
We consider the problem of multicasting a common message signal from a distributed array of wireless transceivers by beamforming to a set of beam targets, while simultaneously protecting a set of null targets by nullforming to them. We describe a distributed algorithm in which each transmitter iteratively adapts its complex transmit weight using common aggregate feedback messages broadcast by the targets, and the local knowledge of only its own channel gains to the targets. This knowledge can be obtained using reciprocity without any explicit feedback. The algorithm minimizes the mean square error between the complex signal amplitudes at the targets and their desired values. We prove convergence of the algorithm, present geometric interpretations, characterize initializations that lead to minimum total transmit power, and prescribe designs for such initializations. We show that the convergence speed is nondecreasing in the number of transmitters if a step size parameter is kept constant. For Rayleigh fading channels, as goes to infinity: 1) convergence can be made arbitrarily fast and 2) beams and nulls can be achieved with vanishing total transmit power even with noise, both with probability one. These results add up to some remarkable scalability properties: the feedback overhead does not grow with the number of transmitters, and with high probability, the algorithm can be configured to converge arbitrarily fast and use vanishingly small total transmit power.
Autors: Amy Kumar;Raghuraman Mudumbai;Soura Dasgupta;Upamanyu Madhow;D. Richard Brown;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 512 - 525
Publisher: IEEE
 
» Distributed Multicast Tree Construction in Wireless Sensor Networks
Abstract:
Multicast tree is a key structure for data dissemination from one source to multiple receivers in wireless networks. Minimum length multica modeled as the Steiner tree problem, and is proven to be NP-hard. In this paper, we explore how to efficiently generate minimum length multi wireless sensor networks (WSNs), where only limited knowledge of network topology is available at each node. We design and analyze a simple algorithm, which we call toward source tree (TST), to build multicast trees in WSNs. We show three metrics of TST algorithm, i.e., running and energy efficiency. We prove that its running time is , the best among all existing solutions to our best knowledge. We prove that TST tree length is in the same order as Steiner tree, which give a theoretical upper bound and use simulations to show the ratio be only 1.114 when nodes are uniformly distributed. We evaluate energy efficiency in terms of message complexity and the number of forwarding prove that they are both order-optimal. We give an efficient way to construct multicast tree in support of transmission of voluminous data.
Autors: Hongyu Gong;Luoyi Fu;Xinzhe Fu;Lutian Zhao;Kainan Wang;Xinbing Wang;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 280 - 296
Publisher: IEEE
 
» Distributed Optimal Control of Reactive Power and Voltage in Islanded Microgrids
Abstract:
This paper presents a distributed optimal control strategy for islanded microgrids, which allows performing reactive power sharing and voltage regulation without using a communication system. To perform the twofold objectives, a small signal model is first developed to reconstruct the system input–output relationship, which is evaluated through sensitivity analysis. A state estimator is then constructed to observe reactive power distribution and system voltages by local measurement. An optimal regulator is developed to perform both reactive power sharing and system voltage restoration. And the dynamic performance of the optimal controller is analyzed, from which the guideline for choosing controller parameters is formulated. The results obtained from sensitivity analysis, simulations, and experiments show that the proposed approach provides the expected reliability and flexibility for optimizing the reactive power sharing and system voltages restoration.
Autors: Yanbo Wang;Xiongfei Wang;Zhe Chen;Frede Blaabjerg;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jan 2017, volume: 53, issue:1, pages: 340 - 349
Publisher: IEEE
 
» Distributed Optimization for Resilient Transmission of Confidential Information in Interference Channels
Abstract:
In this paper, resilient transmission in a multicell multiple-input multiple-output (MIMO) interference wiretap channel model is studied. Each base station (BS) transmits confidential messages to its intended legitimate user with multiple antennas in the presence of eavesdroppers that can overhear the transmission. We study the problem of finding the optimal transmit covariance matrices at the BSs to maximize the secrecy sum rate, which is typically nonconvex and intractable to obtain a globally optimal solution. A distributed iterative optimization algorithm based on a novel decomposition framework across all users is proposed. The decomposition framework preserves the convexity of the objective function and linearizes the nonconvex part. At each iteration, the BSs simultaneously solve a sequence of problems that are decoupled convex approximations of the original secrecy sum-rate function. Moreover, the complexity of the algorithm is analyzed. Numerical results are presented to validate the effectiveness of the proposed distributed algorithm.
Autors: Zhiyu Zhang;Kah Chan Teh;Kwok Hung Li;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jan 2017, volume: 66, issue:1, pages: 494 - 501
Publisher: IEEE
 
» Distributed Robust Bilinear State Estimation for Power Systems with Nonlinear Measurements
Abstract:
This paper proposes a fully distributed robust bilinear state-estimation (D-RBSE) method that is applicable to multi-area power systems with nonlinear measurements. We extend the recently introduced bilinear formulation of state estimation problems to a robust model. A distributed bilinear state-estimation procedure is developed. In both linear stages, the state estimation problem in each area is solved locally, with minimal data exchange with its neighbors. The intermediate nonlinear transformation can be performed by all areas in parallel without any need of inter-regional communication. This algorithm does not require a central coordinator and can compress bad measurements by introducing a robust state estimation model. Numerical tests on IEEE 14-bus, 118-bus benchmark systems, and a 1062-bus system demonstrate the validity of the method.
Autors: Weiye Zheng;Wenchuan Wu;Antonio Gomez-Exposito;Boming Zhang;Ye Guo;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 499 - 509
Publisher: IEEE
 
» Distributed Structure: Joint Expurgation for the Multiple-Access Channel
Abstract:
In this paper, we obtain an improved lower bound on the error exponent of the memoryless multiple-access channel via the use of linear codes, thus demonstrating that structure can be beneficial even when capacity may be achieved via random codes. We show that if the multiple-access channel is additive over a finite field, then any error probability, and hence any error exponent, achievable by a linear code for the associated single-user channel, is also achievable for the multiple-access channel. In particular, linear codes allow to attain joint expurgation, and hence, attain the single-user expurgated exponent of the single-user channel, whenever the latter is achieved by a uniform distribution. Thus, for additive channels, at low rates, where expurgation is needed, our approach strictly improves performance over previous results, where expurgation was used for at most one of the users. Even when the multiple-access channel is not additive, it may be transformed into such a channel. While the transformation is information-lossy, we show that the distributed structure gain in some “nearly additive” cases outweighs the loss. Finally, we apply a similar approach to the Gaussian multiple-access channel. While we believe that due to the power constraints, it is impossible to attain the single-user error exponent, we do obtain an improvement over the best known achievable error exponent, given by Gallager, for certain parameters. This is accomplished using a nested lattice triplet with judiciously chosen parameters.
Autors: Eli Haim;Yuval Kochman;Uri Erez;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 5 - 20
Publisher: IEEE
 

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