Advances in Electrical Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Effect of DC Link Control Strategies on Multiterminal AC-DC Power Flow Sun, 19 Apr 2015 13:21:47 +0000 http://www.hindawi.com/journals/aee/2015/685943/ For power-flow solution of power systems incorporating multiterminal DC (MTDC) network(s), five quantities are required to be solved per converter. On the other hand, only three independent equations comprising two basic converter equations and one DC network equation exist per converter. Thus, for solution, two additional equations are required. These two equations are derived from the control specifications adopted for the DC links. Depending on the application, several combinations of valid control specifications are possible. Each combination of a set of valid control specifications is known as a control strategy. The number of control strategies increases with an increase in the number of the DC terminals or converters. It is observed that the power-flow convergence of integrated AC-MTDC power systems is strongly affected by the control strategy adopted for the DC links. This work investigates the mechanism by which different control strategies affect the power-flow convergence pattern of AC-MTDC power systems. To solve the DC variables in the Newton-Raphson (NR) power-flow model, sequential method is considered in this paper. Numerous case studies carried out on a three-terminal DC network incorporated in the IEEE-300 bus test system validate this. Shagufta Khan and Suman Bhowmick Copyright © 2015 Shagufta Khan and Suman Bhowmick. All rights reserved. Multiobjective Economic Load Dispatch Problem Solved by New PSO Thu, 19 Feb 2015 08:43:27 +0000 http://www.hindawi.com/journals/aee/2015/536040/ Proposed in this paper is a new particle swarm optimization technique for the solution of economic load dispatch as well as environmental emission of the thermal power plant with power balance and generation limit constraints. Economic load dispatch is an online problem to minimize the total generating cost of the thermal power plant and satisfy the equality and inequality constraints. Thermal power plants use fossil fuels for the generation of power; fossil fuel emits many toxic gases which pollute the environment. This paper not only considers the economic load dispatch problem to reduce the total generation cost of the thermal power plant but also deals with environmental emission minimization. In this paper, fuel cost and the environmental emission functions are considered and formulated as a multiobjective economic load dispatch problem. For obtaining the solution of multiobjective economic load dispatch problem a new PSO called moderate random search PSO was used. MRPSO enhances the ability of particles to explore in the search spaces more effectively and increases their convergence rates. The proposed algorithm is tested for the IEEE 30 bus test systems. The results obtained by MRPSO algorithm show that it is effective and efficient. Nagendra Singh and Yogendra Kumar Copyright © 2015 Nagendra Singh and Yogendra Kumar. All rights reserved. Development of Power Electronics Based Test Platform for Characterization and Testing of Magnetocaloric Materials Sat, 31 Jan 2015 12:35:37 +0000 http://www.hindawi.com/journals/aee/2015/670624/ Magnetocaloric effects of various materials are getting more and more interesting for the future, as they can significantly contribute towards improving the efficiency of many energy intensive applications such as refrigeration, heating, and air conditioning. Accurate characterization of magnetocaloric effects, exhibited by various materials, is an important process for further studies and development of the suitable magnetocaloric heating and cooling solutions. The conventional test facilities have plenty of limitations, as they focus only on the thermodynamic side and use magnetic machines with moving bed of magnetocaloric material or magnet. In this work an entirely new approach for characterization of the magnetocaloric materials is presented, with the main focus on a flexible and efficient power electronic based excitation and a completely static test platform. It can generate a periodically varying magnetic field using superposition of an ac and a dc magnetic field. The scale down prototype uses a customized single phase H-bridge inverter with essential protections and an electromagnet load as actuator. The preliminary simulation and experimental results show good agreement and support the usage of the power electronic test platform for characterizing magnetocaloric materials. Deepak Elamalayil Soman, Jelena Loncarski, Lisa Gerdin, Petter Eklund, Sandra Eriksson, and Mats Leijon Copyright © 2015 Deepak Elamalayil Soman et al. All rights reserved. I/Q Imbalance Problem in SC-FDMA System with DCT and DFT Basis Functions Thu, 29 Jan 2015 08:01:32 +0000 http://www.hindawi.com/journals/aee/2015/723805/ In-phase/quadrature-phase (I/Q) imbalance is one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. This paper investigates and analyzes the impacts of the I/Q imbalance on the performance of the single-carrier frequency-division multiple access (SC-FDMA) system with different basis functions by computer simulations only. The suitable phase and amplitude of I and Q branches that can be utilized in SC-FDMA system are studied and determined through simulations for different I/Q imbalance scenarios and different subcarrier mapping schemes. Simulation results show that the phase and amplitude of I and Q branches have significant effects on the bit error rate (BER) performance of the SC-FDMA system. F. S. Al-kamali, Hefdhallah Sakran, and N. A. Odhah Copyright © 2015 F. S. Al-kamali et al. All rights reserved. Characterization and Modeling of Received Signal Strength and Charging Time for Wireless Energy Transfer Tue, 20 Jan 2015 08:05:58 +0000 http://www.hindawi.com/journals/aee/2015/621306/ Wireless sensor networks can provide effective means for monitoring and controlling a wide range of applications. Recently, tremendous effort was directed towards devising sensors powered from ambient sources such as heat, wind, and vibration. Wireless energy transfer is another source that has attractive features that make it a promising candidate for supplying power to wireless sensor nodes. This paper is concerned with characterizing and modeling the charging time and received signal strength indicator for wireless energy transfer system. These parameters play a vital role in deciding the geometry of sensor network and the routing protocols to be deployed. The development of communication protocols for wireless-powered wireless sensor networks is also improved with the knowledge of such models. These two quantities were computed from data acquired at various coordinates of the harvester relative to a fixed position of RF energy source. Data was acquired for indoor and outdoor scenarios using the commercially available PowerCast energy harvester and evaluation board. Mathematical models for both indoor and outdoor environments were developed and analyzed. A few guidelines on how to use these models were suggested. Finally, the possibility of harvesting the energy from the ambient RF power to energize wireless sensor nodes was also investigated. Uthman Baroudi, Amin-ud-din Qureshi, and Samir Mekid Copyright © 2015 Uthman Baroudi et al. All rights reserved. A Cancellation-Free Symbolic Sensitivity Technique Based on Network Determinant Expansion Sun, 18 Jan 2015 12:57:01 +0000 http://www.hindawi.com/journals/aee/2015/328517/ The generalization of Bode’s sensitivity analysis technique for all types of the transfer functions and circuit elements is presented in the paper. The proposed formulae for first- and second-order symbolic sensitivity calculation provide the compact size of obtained expression and have the advantages of cancellation-free sum-of-product terms and matrix-free computation. This is achieved by means of the concept of high order summative cofactors and the generalized parameter extraction method. The proposed technique is implemented in symbolic circuit analysis program Cirsym. Illustrative example on symbolic sensitivity circuit analysis and comparison of the presented technique with the transimpedance method and the method based on the modified Coates flow-graph are given. Vladimir Filaretov, Konstantin Gorshkov, and Sergey Kurganov Copyright © 2015 Vladimir Filaretov et al. All rights reserved. Filter Bank Multicarrier Modulation: A Waveform Candidate for 5G and Beyond Sun, 21 Dec 2014 00:10:11 +0000 http://www.hindawi.com/journals/aee/2014/482805/ Recent discussions on viable technologies for 5G emphasize on the need for waveforms with better spectral containment per subcarrier than the celebrated orthogonal frequency division multiplexing (OFDM). Filter bank multicarrier (FBMC) is an alternative technology that can serve this need. Subcarrier waveforms are built based on a prototype filter that is designed with this emphasis in mind. This paper presents a broad review of the research work done in the wireless laboratory of the University of Utah in the past 15 years. It also relates this research to the works done by other researchers. The theoretical basis based on which FBMC waveforms are constructed is discussed. Also, various methods of designing effective prototype filters are presented. For completeness, polyphase structures that are used for computationally efficient implementation of FBMC systems are introduced and their complexity is contrasted with that of OFDM. The problems of channel equalization as well as synchronization and tracking methods in FBMC systems are given a special consideration and a few outstanding research problems are identified. Moreover, this paper brings up a number of appealing features of FBMC waveforms that make them an ideal choice in the emerging areas of multiuser and massive MIMO networks. Behrouz Farhang-Boroujeny Copyright © 2014 Behrouz Farhang-Boroujeny. All rights reserved. Caching Eliminates the Wireless Bottleneck in Video Aware Wireless Networks Sun, 30 Nov 2014 11:38:20 +0000 http://www.hindawi.com/journals/aee/2014/261390/ Wireless video is the main driver for rapid growth in cellular data traffic. Traditional methods for network capacity increase are very costly and do not exploit the unique features of video, especially asynchronous content reuse. In this paper we give an overview of our work that proposed and detailed a new transmission paradigm exploiting content reuse and the widespread availability of low-cost storage. Our network structure uses caching in helper stations (femtocaching) and/or devices, combined with highly spectrally efficient short-range communications to deliver video files. For femtocaching, we develop optimum storage schemes and dynamic streaming policies that optimize video quality. For caching on devices, combined with device-to-device (D2D) communications, we show that communications within clusters of mobile stations should be used; the cluster size can be adjusted to optimize the tradeoff between frequency reuse and the probability that a device finds a desired file cached by another device in the same cluster. In many situations the network throughput increases linearly with the number of users, and the tradeoff between throughput and outage is better than in traditional base-station centric systems. Simulation results with realistic numbers of users and channel conditions show that network throughput can be increased by two orders of magnitude compared to conventional schemes. Andreas F. Molisch, Giuseppe Caire, David Ott, Jeffrey R. Foerster, Dilip Bethanabhotla, and Mingyue Ji Copyright © 2014 Andreas F. Molisch et al. All rights reserved. Performance of Various Metaheuristic Techniques for Economic Dispatch Problem with Valve Point Loading Effects and Multiple Fueling Options Thu, 27 Nov 2014 13:25:11 +0000 http://www.hindawi.com/journals/aee/2014/765053/ The paper presents the metaheuristic approaches based on pattern search and simulated annealing hybridized with sequential quadratic programming, a powerful nonlinear adaptive technique for estimation of the finest combination of generated power in a given system at lowest operating cost while sustaining the operating condition of system efficiently. The fuel cost is minimized by satisfying the nonlinear operating conditions of thermal units mainly based on generation capacity constraints, generator ramp limit, power balance constraints, and valve point loading effect and by keeping in view the prohibited operating zones, respectively. About the optimization, a comparative study is made for pattern search (PS) and simulated annealing (SA), as a viable global search technique and sequential quadratic programming, an efficient local optimizer and their hybrid versions. The applicability, stability, and reliability of the designed approaches are validated through comprehensive statistical analysis based on Monte Carlo simulations. Ijaz Ahmed, Ali Rauf Rao, Alaf Shah, Engr Alamzeb, and Junaid Ali Khan Copyright © 2014 Ijaz Ahmed et al. All rights reserved. Active Fault Tolerant Control Based on Bond Graph Approach Mon, 10 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/aee/2014/216153/ This paper proposes a structural fault recoverability analysis using the bond graph (BG) approach. Indeed, this tool enables structural analysis for diagnosis and fault tolerant control (FTC). For the FTC, we propose an approach based on the inverse control using the inverse BG. The fault tolerant control method is also compared with another approach. Finally, simulation results are presented to show the performance of the proposed approach. Manel Allous and Nadia Zanzouri Copyright © 2014 Manel Allous and Nadia Zanzouri. All rights reserved. Proton Irradiations on SJ HV Power MOSFETs to Realize Fast Diode Devices Mon, 03 Nov 2014 10:21:42 +0000 http://www.hindawi.com/journals/aee/2014/423803/ This paper studies the effects of proton irradiations on Super Junction High Voltage power MOSFETs to realize transistors with fast diode. Experiments were performed on a sample of 600 V power MOSFETs and achieved results were compared to standard irradiated devices by electrons. Ignazio Bertuglia, Giuseppe Consentino, and Michele Laudani Copyright © 2014 Ignazio Bertuglia et al. All rights reserved. Nonconvex Economic Dispatch Using Particle Swarm Optimization with Time Varying Operators Sun, 12 Oct 2014 07:15:45 +0000 http://www.hindawi.com/journals/aee/2014/301615/ This paper presents a particle swarm optimization (PSO) to solve hard combinatorial constrained optimization problems such as nonconvex and discontinuous economic dispatch (ED) problem of large thermal power plants. Several measures have been suggested in the control equation of the classical PSO by modifying its operators for better exploration and exploitation. The inertia operator of the PSO is modulated by introducing a new truncated sinusoidal function. The cognitive and social behaviors are dynamically controlled by suggesting new exponential constriction functions. The overall methodology effectively regulates the velocity of particles during their flight and results in substantial improvement in the classical PSO. The effectiveness of the proposed method has been tested for economic load dispatch of three standard test systems considering various operational constraints like valve-point loading effect, prohibited operating zones (POZs), network power loss, and so forth. The application results show that the proposed PSO method is very promising. Vinay Kumar Jadoun, Nikhil Gupta, K. R. Niazi, and Anil Swarnkar Copyright © 2014 Vinay Kumar Jadoun et al. All rights reserved. Peak Voltage Measurements Using Standard Sphere Gap Method Wed, 08 Oct 2014 13:00:28 +0000 http://www.hindawi.com/journals/aee/2014/980913/ The paper presents a measurement system of peak value of high voltage (H.V.) using 150 mm diameter sphere gap, disposed in vertical position. Experimental breakdown results have been compared with standard values at atmospheric reference conditions STC (20°C, 101.3 kPa, or 760 mmHg). The main experimental and theoretical characteristics are presented. Constantin Ungureanu and Lăcrămioara Mihaela Nemțoi Copyright © 2014 Constantin Ungureanu and Lăcrămioara Mihaela Nemțoi. All rights reserved. QPSO versus BSA for Failure Correction of Linear Array of Mutually Coupled Parallel Dipole Antennas with Fixed Side Lobe Level and VSWR Sun, 28 Sep 2014 11:19:41 +0000 http://www.hindawi.com/journals/aee/2014/858290/ Evolutionary algorithms play an important role in synthesizing linear array antenna. In this paper, the authors have compared quantum particle swarm optimization (QPSO) and backtracking search algorithms (BSA) in failure correction of linear antenna arrays constructed using half wavelength uniformly spaced dipoles. The QPSO algorithm is a combination of classical PSO and quantum mechanics principles to enhance the performance of PSO and BSA is considered as a modernized PSO using historical populations. These two algorithms are applied to obtain the voltage excitations of the nondefective elements in the failed antenna array such that the necessary objectives, namely, the minimization of parameters like side lobe level (SLL) and voltage standing wave ratio (VSWR), are achieved leading to their values matching closely the desired parameter values. The results of both algorithms are compared in terms of parameters used in the objective function along their statistical parameters. Moreover, in order to reduce the processing time, inverse fast Fourier transform (IFFT) is used to obtain the array factor. In this paper, an example is presented for the application of the above two algorithms for a linear array of 30 parallel half wavelength dipole antennas failed with 4 elements and they clearly show the effectiveness of both the QPSO and BSA algorithms in terms of optimized parameters, statistical values, and processing time. R. Muralidharan, Vallavaraj Athinarayanan, G. K. Mahanti, and Ananya Mahanti Copyright © 2014 R. Muralidharan et al. All rights reserved. Parameter Estimation of Turbo Code Encoder Thu, 18 Sep 2014 09:10:16 +0000 http://www.hindawi.com/journals/aee/2014/282108/ The problem of reconstruction of a channel code consists of finding out its design parameters solely based on its output. This paper investigates the problem of reconstruction of parallel turbo codes. Reconstruction of a turbo code has been addressed in the literature assuming that some of the parameters of the turbo encoder, such as the number of input and output bits of the constituent encoders and puncturing pattern, are known. However in practical noncooperative situations, these parameters are unknown and should be estimated before applying reconstruction process. Considering such practical situations, this paper proposes a novel method to estimate the above-mentioned code parameters. The proposed algorithm increases the efficiency of the reconstruction process significantly by judiciously reducing the size of search space based on an analysis of the observed channel code output. Moreover, simulation results show that the proposed algorithm is highly robust against channel errors when it is fed with noisy observations. Mehdi Teimouri and Ahmadreza Hedayat Copyright © 2014 Mehdi Teimouri and Ahmadreza Hedayat. All rights reserved. Musical Rhythms Affect Heart Rate Variability: Algorithm and Models Wed, 17 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/aee/2014/851796/ There were a lot of psychological music experiments and models but there were few psychological rhythm experiments and models. There were a lot of physiological music experiments but there were few physiological music models. There were few physiological rhythm experiments but there was no physiological rhythm model. We proposed a physiological rhythm model to fill this gap. Twenty-two participants, 4 drum loops as stimuli, and electrocardiogram (ECG) were employed in this work. We designed an algorithm to map tempo, complexity, and energy into two heart rate variability (HRV) measures, the standard deviation of normal-to-normal heartbeats (SDNN) and the ratio of low- and high-frequency powers (LF/HF); these two measures form the physiological valence/arousal plane. There were four major findings. Initially, simple and loud rhythms enhanced arousal. Secondly, the removal of fast and loud rhythms decreased arousal. Thirdly, fast rhythms increased valence. Finally, the removal of fast and quiet rhythms increased valence. Our work extended the psychological model to the physiological model and deepened the musical model into the rhythmic model. Moreover, this model could be the rules of automatic music generating systems. Hui-Min Wang and Sheng-Chieh Huang Copyright © 2014 Hui-Min Wang and Sheng-Chieh Huang. All rights reserved. Pulse Edge-Only Signaling Method Comparison for Wireline Interconnects Sun, 14 Sep 2014 10:50:09 +0000 http://www.hindawi.com/journals/aee/2014/938460/ Typical high-speed electrical transmission lines use a variety of precoding and equalization techniques to counter the frequency-dependent channel loss and environmental conditions such as ISI. In this paper, we suggest a relatively narrow-band signaling method that is resilient to the effects of ISI and crosstalk and can be implemented with existing technology. Alternative modulation schemes are analyzed in terms of effectiveness, performance, and cost. In particular, line-encoded and on-off keyed modulation methods are evaluated in simulations of transmission lines to gauge effectiveness in high-speed conditions with limiting ISI. Dmitriy Garmatyuk, Kyle Kauffman, and Andrew Martwick Copyright © 2014 Dmitriy Garmatyuk et al. All rights reserved. Robust Adaptive Fault-Tolerant Tracking Control of Three-Phase Induction Motor Thu, 04 Sep 2014 00:00:00 +0000 http://www.hindawi.com/journals/aee/2014/915072/ This paper deals with the problem of induction motor tracking control against actuator faults and external disturbances using the linear matrix inequalities (LMIs) method and the adaptive method. A direct adaptive fault-tolerant tracking controller design method is developed based on Lyapunov stability theory and a constructive algorithm based on linear matrix inequalities for online tuning of adaptive and state feedback gains to stabilize the closed-loop system in order to reduce the fault effect with disturbance attenuation. Simulation results reveal the merits of proposed robust adaptive fault-tolerant tracking control scheme on an induction motor subjected to actuator faults. Hossein Tohidi and Koksal Erenturk Copyright © 2014 Hossein Tohidi and Koksal Erenturk. All rights reserved. Multimodel Robust Control for Hydraulic Turbine Mon, 25 Aug 2014 09:36:41 +0000 http://www.hindawi.com/journals/aee/2014/512628/ The paper deals with the multimodel and robust control system design and their combination based on structure. Controller design will be done in the frequency domain with nominal performance specified by phase margin. Hydraulic turbine model is analyzed as system with unstructured uncertainty, and robust stability condition is included in controller design. Multimodel and robust control approaches are presented in detail on hydraulic turbine model. Control design approaches are compared and used for derivation of new approaches which combine advantages of both. Jakub Osuský and Stanislav Števo Copyright © 2014 Jakub Osuský and Stanislav Števo. All rights reserved. The Design of Frequency Filters of Iterative Feedback Tuning Using Particle Swarm Optimization Mon, 25 Aug 2014 06:11:38 +0000 http://www.hindawi.com/journals/aee/2014/465127/ Iterative feedback tuning (IFT) is a data-based tuning approach that minimizes a quadratic performance index using some closed-loop experimental data. A control weighting coefficient, known as lambda, and two frequency filters are the most important parameters which can significantly improve the performance of the method. One of the major problems in IFT is tuning these parameters. This paper presents a new approach to tune frequency filters using particle swarm optimization (PSO). At the end, the performance of the proposed method is evaluated by two case study simulations. Arman Sharifi Copyright © 2014 Arman Sharifi. All rights reserved. Towards the Smart Grid: Substation Automation Architecture and Technologies Wed, 20 Aug 2014 00:00:00 +0000 http://www.hindawi.com/journals/aee/2014/896296/ This paper deals with Industrial Control Systems (ICS) of the electrical sector and especially on the Smart Grid. This sector has been particularly active at establishing new standards to improve interoperability between all sector players, driven by the liberalization of the market and the introduction of distributed generation of energy. The paper provides a state-of-the-art analysis on architectures, technologies, communication protocols, applications, and information standards mainly focusing on substation automation in the transmission and distribution domain. The analysis shows that there is tremendous effort from the Smart Grid key stakeholders to improve interoperability across the different components managing an electrical grid, from field processes to market exchanges, allowing the information flowing more and more freely across applications and domains and creating opportunity for new applications that are not any more constraint to a single domain. A. Leonardi, K. Mathioudakis, A. Wiesmaier, and F. Zeiger Copyright © 2014 A. Leonardi et al. All rights reserved. Single Active Element Based Voltage-Mode Multifunction Filter Mon, 18 Aug 2014 00:00:00 +0000 http://www.hindawi.com/journals/aee/2014/514019/ The paper presents a new voltage-mode multifunction filter. The proposed filter employs single modified fully differential second generation current conveyor (FDCCII), two grounded capacitors, and three resistors. The proposed circuit enjoys the employment of two grounded capacitors (attractive for absorbing shunt parasitic capacitance and ideal for IC implementation). The proposed circuit provides all five generic filter responses (low pass (LP), high pass (HP), band pass (BP), notch (NH), and all pass (AP) filter responses) simultaneously with single input. The novel proposed filter has low active and passive sensitivities. A number of time domain and frequency domain simulation results depicted through PSPICE using 0.18 µm TSMC process parameters are included to validate the theory. The proposed circuit is expected to enhance the existing knowledge on the subject. Jitendra Mohan, Bhartendu Chaturvedi, and Sudhanshu Maheshwari Copyright © 2014 Jitendra Mohan et al. All rights reserved. Multiobjective Genetic Algorithms Program for the Optimization of an OTA for Front-End Electronics Wed, 13 Aug 2014 07:08:25 +0000 http://www.hindawi.com/journals/aee/2014/374741/ The design of an interface to a specific sensor induces costs and design time mainly related to the analog part. So to reduce these costs, it should have been standardized like digital electronics. The aim of the present work is the elaboration of a method based on multiobjectives genetic algorithms (MOGAs) to allow automated synthesis of analog and mixed systems. This proposed methodology is used to find the optimal dimensional transistor parameters (length and width) in order to obtain operational amplifier performances for analog and mixed CMOS-(complementary metal oxide semiconductor-) based circuit applications. Six performances are considered in this study, direct current (DC) gain, unity-gain bandwidth (GBW), phase margin (PM), power consumption (P), area (A), and slew rate (SR). We used the Matlab optimization toolbox to implement the program. Also, by using variables obtained from genetic algorithms, the operational transconductance amplifier (OTA) is simulated by using Cadence Virtuoso Spectre circuit simulator in standard TSMC (Taiwan Semiconductor Manufacturing Company) RF 0.18 μm CMOS technology. A good agreement is observed between the program optimization and electric simulation. Abdelghani Dendouga, Slimane Oussalah, Damien Thienpont, and Abdenour Lounis Copyright © 2014 Abdelghani Dendouga et al. All rights reserved. Performance Analysis of a Shunt Compensator Controlled Using Modified Synchronous Reference Theory Thu, 07 Aug 2014 11:36:17 +0000 http://www.hindawi.com/journals/aee/2014/392187/ This paper deals with the control of distribution energy resource (DER) connected to a grid connected system feeding nonlinear loads. The DER is controlled to provide power quality improvement capabilities, namely, power factor correction, harmonic reduction, and load balancing. The developed controller is based on modification of synchronous reference theory. It possesses unique features such as filtration and fundamental voltage extraction from the polluted grid voltages to eliminate harmonics and unbalance. Additionally, the control is implemented over the square of DC link voltage. The distributed generation source is realized as a voltage source converter. Both simulation and experimental results prove the effectiveness of control algorithm with nonlinear loads. The control algorithm works well for power factor correction, harmonic reduction, and operation under unbalanced load condition. The dynamics of the system under load change and load unbalancing are well depicted. Alka Singh Copyright © 2014 Alka Singh. All rights reserved. Design of Tunable Monopole Arm Planar Spiral Antenna for Cognitive Radio Thu, 24 Jul 2014 14:03:58 +0000 http://www.hindawi.com/journals/aee/2014/593194/ This paper presents a spiral antenna design operating in the frequency range of 1–15 GHz having both selective notch bands and wideband response. The main feed arm of spiral antenna is configured as rectangular monopole of width quarter wavelength to achieve impedance matching with standard 50 Ω excitation. Frequency tuning in the design is achieved by placing varactor diode at an appropriate position along the spiral arms and in the ground plane. The design offers a peak gain of 3.4 dB (simulated) and 3 dB (measured). The unique frequency response of antenna makes its suitable to be used for front-end system of cognitive radio for sensing the spectrum in various modes. Rahul Yadav Copyright © 2014 Rahul Yadav. All rights reserved. Assessment of Electrical Load in Water Distribution Systems Using Representative Load Profiles-Based Method Mon, 21 Jul 2014 07:00:46 +0000 http://www.hindawi.com/journals/aee/2014/865621/ The problem of optimal management of a water distribution system includes the determination of the operation regime for each hydrophore station. The optimal operation of a water distribution system means a maximum attention to assess the demands of the water, with minimum electrical energy consumption. The analysis of load profiles corresponding to a water distribution system can be the first step that water companies must make to assess the electrical energy consumption. This paper presents a new method to assess the electrical load in water distribution systems, taking into account the time-dependent evolution of loads from the hydrophore stations. The proposed method is tested on a real urban water distribution system, showing its effectiveness in obtaining the electrical energy consumption with a relatively low computational burden. Gheorghe Grigoras Copyright © 2014 Gheorghe Grigoras. All rights reserved. Row-Based Dual Assignment, for a Level Converter Free CSA Design and Its Near-Threshold Operation Tue, 15 Jul 2014 12:11:07 +0000 http://www.hindawi.com/journals/aee/2014/814975/ Subthreshold circuit designs are very much popular for some of the ultra-low power applications, where the minimum energy consumption is the primary concern. But, due to the weak driving current, these circuits generally suffer from huge performance degradation. Therefore, in this paper, we primarily targeted analyzing the performance of a near-threshold circuit (NTC), which retains the excellent energy efficiency of the subthreshold design, while improving the performance to a certain extent. A modified row-based dual 4-operand carry save adder (CSA) design has been reported in the present work using 45 nm technology. Moreover, to find out the effectiveness of the near-threshold operation of the 4-operand CSA design, it has been compared with the other design styles. From the simulation results, obtained for the frequency of 20 MHz, we found that the proposed scheme of CSA design consumes Watt of average power (), which is almost 90.9% lesser than that of the conventional CSA design, whereas, looking at the perspective of maximum delay at output, the proposed scheme of CSA design provides a fair 44.37% improvement, compared to that of the subthreshold CSA design. Dipankar Saha, Aanan Chatterjee, Sayan Chatterjee, and C. K. Sarkar Copyright © 2014 Dipankar Saha et al. All rights reserved. A Blind Blur Detection Scheme Using Statistical Features of Phase Congruency and Gradient Magnitude Tue, 15 Jul 2014 07:09:25 +0000 http://www.hindawi.com/journals/aee/2014/521027/ The growing uses of camera-based barcode readers have recently gained a lot of attention. This has boosted interest in no-reference blur detection algorithms. Blur is an undesirable phenomenon which appears as one of the most frequent causes of image degradation. In this paper we present a new no-reference blur detection scheme that is based on the statistical features of phase congruency and gradient magnitude maps. Blur detection is achieved by approximating the functional relationship between these features using a feed forward neural network. Simulation results show that the proposed scheme gives robust blur detection scheme. Shamik Tiwari, V. P. Shukla, S. R. Biradar, and A. K. Singh Copyright © 2014 Shamik Tiwari et al. All rights reserved. Fast Transforms in Image Processing: Compression, Restoration, and Resampling Sun, 06 Jul 2014 11:25:54 +0000 http://www.hindawi.com/journals/aee/2014/276241/ Transform image processing methods are methods that work in domains of image transforms, such as Discrete Fourier, Discrete Cosine, Wavelet, and alike. They proved to be very efficient in image compression, in image restoration, in image resampling, and in geometrical transformations and can be traced back to early 1970s. The paper reviews these methods, with emphasis on their comparison and relationships, from the very first steps of transform image compression methods to adaptive and local adaptive filters for image restoration and up to “compressive sensing” methods that gained popularity in last few years. References are made to both first publications of the corresponding results and more recent and more easily available ones. The review has a tutorial character and purpose. Leonid P. Yaroslavsky Copyright © 2014 Leonid P. Yaroslavsky. All rights reserved. Modelling and Simulation of Static Excitation System in Synchronous Machine Operation and Investigation of Shaft Voltage Thu, 03 Jul 2014 09:16:21 +0000 http://www.hindawi.com/journals/aee/2014/727295/ Static excitation system (SES) has been implemented in a specially designed synchronous machine installed in a testing laboratory. This is a large capacity single machine operated in dual mode (i.e., motor or generator) with the help of static sources. It is well known that bearings of the rotating machines are vulnerable to the effects of the shaft voltages caused by the static sources. Shaft voltage is the prime concern for this special machine too due to SES. To find out the exact cause of the shaft voltage, SES of this machine has been modelled with Power Systems software. Various waveforms drawn from the model are validated through computer simulations and actual laboratory tests. Sources of shaft voltages are also analysed thereafter with the FFT analysis of the rotor voltage and current waveforms. Arun Kumar Datta, Manisha Dubey, and Shailendra Jain Copyright © 2014 Arun Kumar Datta et al. All rights reserved.