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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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The Korean Institute of Electrical Engineers
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Volume 11, Issue 4 - Jul 2016
Volume 11, Issue 3 - May 2016
Volume 11, Issue 2 - Mar 2016
Volume 11, Issue 1 - Jan 2016
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A Comparison Study of MIMO Water Wall Model with Linear, MFNN and ESN Models
Moon, Un-Chul ; Lim, Jaewoo ; Lee, Kwang Y. ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 265~273
DOI : 10.5370/JEET.2016.11.2.265
A water wall system is one of the most important components of a boiler in a thermal power plant, and it is a nonlinear Multi-Input and Multi-Output (MIMO) system, with 6 inputs and 3 outputs. Three models are developed and comp for the controller design, including a linear model, a multilayer feed-forward neural network (MFNN) model and an Echo State Network (ESN) model. First, the linear model is developed by linearizing a given nonlinear model and is analyzed as a function of the operating point. Second, the MFNN and the ESN are developed by using training data from the nonlinear model. The three models are validated using Matlab with nonlinear input-output data that was not used during training.
Integrated Voltage and Power Flow Management Considering the Cost of Opera in Active Distribution Networks
Xu, Tao ; Guo, Lingxu ; Wei, Wei ; Wang, Xiaoxue ; Wang, Chengshan ; Lin, Jun ; Li, Tianchu ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 274~284
DOI : 10.5370/JEET.2016.11.2.274
The increasing penetration of distributed energy resources on the distribution networks have brought a number of technical impacts where voltage and thermal variations have been identified as the dominant effects. Active network management in distribution networks aims to integrate distributed energy resources with flexible network management so that distributed energy resources are organized to make better use of existing capacity and infrastructure. This paper propose active solutions which aims to solve the voltage and thermal issues in a distributed manner utilizing a collaborative approach. The proposed algorithms have been fully tested on a distribution network with distributed generation units.
Electricity Pricing Policy Alternatives to Control Rapid Electrification in Korea
Kim, Changseob ; Shin, Jungwoo ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 285~299
DOI : 10.5370/JEET.2016.11.2.285
Although South Korea experienced a rolling blackout in 2011, the possibility of a blackout in South Korea continues to increase due to rapid electrification. This study examines the problems of energy taxation and price distortions as possible reasons for the rapid electrification in South Korea, which is occurring at a faster rate than in Japan, Europe, and other developed countries. Further, we suggest new energy taxation and price systems designed to normalize electricity prices. In order to do so, we consider two possible scenarios: the first imposes a tax on bituminous coal for electricity generation and the second levies a tax to provide compensation for the potential damages from a nuclear accident. Based on these scenarios, we analyze the effects of a new energy system on electricity price and demand. The results show that a new energy system could guarantee the power generation costs and balance the relative prices between energy sources, and could also help prevent rapid electrification. Therefore, the suggested new energy system is expected to be utilized as a basis for energy policy to decrease the speed of electrification, thus preventing a blackout, and to induce the rational consumption of energy in South Korea.
Provision of Two-area Automatic Generation Control by Demand-side Electric Vehicle Battery Swapping Stations
Xie, Pingping ; Shi, Dongyuan ; Li, Yinhong ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 300~308
DOI : 10.5370/JEET.2016.11.2.300
Application of demand-side resources to automatic generation control (AGC) has a great significance for improving the dynamic control performance of power system frequency regulation. This paper investigates the possibility of providing regulation services by demand-side energy storage in electric vehicle battery swapping stations (BSS). An interaction framework, namely station-to-grid (S2G), is presented to integrate BSS energy storage into power grid for giving benefits to frequency regulation. The BSS can be regarded as a lumped battery energy storage station through S2G framework. A supplementary AGC method using demand-side BSS energy storage is developed considering the vehicle user demand of battery swapping. The effects to the AGC performance are evaluated through simulations by using a two-area interconnected power grid model with step and random load disturbance. The results show that the demand-side BSS can significantly suppress the frequency deviation and tie-line power fluctuations.
Recognition and Classification of Power Quality Disturbances on the basis of Pattern Linguistic Values
Liu, XiaoSheng ; Liu, Bo ; Xu, DianGuo ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 309~319
DOI : 10.5370/JEET.2016.11.2.309
This paper presents a new recognition and classification method for power quality (PQ) disturbances on the basis of pattern linguistic values. This method solves the difficulty of recognizing disturbances rapidly and accurately by using fuzzy logic. This method uses classification disturbance patterns to define the linguistic values of fuzzy input variables and used the input variables of corresponding disturbance pattern to set membership functions. This method also sets the fuzzy rules by analyzing the distribution regularities of the input variable values. One characteristic of this method is that the linguistic values of fuzzy input variables and the setting of membership functions are not only related to the input variables but also to the character of classification disturbance and the classification results. Furthermore, the number of fuzzy rules is equal to the number of disturbance patterns. By using this method for disturbance classification, the membership function and design of fuzzy rules are directly related to the objective of classification, thus effectively reducing the complexity of the design process and yielding accurate classification results. The classification results of the simulation and measured data verify the feasibility and effectiveness of this method.
Critical Short Circuit Ratio Analysis on DFIG Wind Farm with Vector Power Control and Synchronized Control
Hong, Min ; Xin, Huanhai ; Liu, Weidong ; Xu, Qian ; Zheng, Taiying ; Gan, Deqiang ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 320~328
DOI : 10.5370/JEET.2016.11.2.320
The introduction of renewable energy sources into the AC grid can change and weaken the strength of the grid, which will in turn affect the stability and robustness of the doubly-fed induction generator (DFIG) wind farm. When integrated with weak grids, the DFIG wind turbine with vector power control often suffers from poor performance and robustness, while the DFIG wind turbine with synchronized control provides better stability. This paper investigates the critical short circuit ratios of DFIG wind turbine with vector power control and synchronized control, to analyze the stability boundary of the DFIG wind turbine. Frequency domain methods based on sensitivity and complementary sensitivity of transfer matrix are used to investigate the stability boundary conditions. The critical capacity of DFIG wind farm with conventional vector power control at a certain point of common coupling (PCC) is obtained and is further increased by employing synchronized control properly. The stability boundary is validated by electromagnetic transient simulation of an offshore wind farm connected to a real regional grid.
Optimal Voltage and Reactive Power Scheduling for Saving Electric Charges using Dynamic Programming with a Heuristic Search Approach
Jeong, Ki-Seok ; Chung, Jong-Duk ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 329~337
DOI : 10.5370/JEET.2016.11.2.329
With the increasing deployment of distributed generators in the distribution system, a very large search space is required when dynamic programming (DP) is applied for the optimized dispatch schedules of voltage and reactive power controllers such as on-load tap changers, distributed generators, and shunt capacitors. This study proposes a new optimal voltage and reactive power scheduling method based on dynamic programming with a heuristic searching space reduction approach to reduce the computational burden. This algorithm is designed to determine optimum dispatch schedules based on power system day-ahead scheduling, with new control objectives that consider the reduction of active power losses and maintain the receiving power factor. In this work, to reduce the computational burden, an advanced voltage sensitivity index (AVSI) is adopted to reduce the number of load-flow calculations by estimating bus voltages. Moreover, the accumulated switching operation number up to the current stage is applied prior to the load-flow calculation module. The computational burden can be greatly reduced by using dynamic programming. Case studies were conducted using the IEEE 30-bus test systems and the simulation results indicate that the proposed method is more effective in terms of saving electric charges and improving the voltage profile than loss minimization.
Optimization of Generator Maintenance Scheduling with Consideration on the Equivalent Operation Hours
Han, Sangheon ; Kim, Hyoungtae ; Lee, Sungwoo ; Kim, Wook ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 338~346
DOI : 10.5370/JEET.2016.11.2.338
In order for the optimal solution of generators’ annual maintenance scheduling to be applicable to the actual power system it is crucial to incorporate the constraints related to the equivalent operation hours (EOHs) in the optimization model. However, most of the existing researches on the optimal maintenance scheduling are based on the assumption that the maintenances are to be performed periodically regardless of the operation hours. It is mainly because the computation time to calculate EOHs increases exponentially as the number of generators becomes larger. In this paper an efficient algorithm based on demand grouping method is proposed to calculate the approximate EOHs in an acceptable computation time. The method to calculate the approximate EOHs is incorporated into the optimization model for the maintenance scheduling with consideration on the EOHs of generators. The proposed method is successfully applied to the actual Korean power system and shows significant improvement when compared to the result of the maintenance scheduling algorithm without consideration on EOHs.
Sensorless Speed Control of Permanent Magnet Synchronous Motor by Unscented Kalman Filter using Various Scaling Parameters
Moon, Cheol ; Kwon, Young Ahn ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 347~352
DOI : 10.5370/JEET.2016.11.2.347
This paper investigates the application, design and implementation of unscented Kalman filter observer using the various scaling parameters for the sensorless speed control of a permanent magnet synchronous motor. The principles of unscented transformation and unscented Kalman filter are examined and their applications are explained. Typically the mapping transformation process is divided into two types, namely the basic unscented transformation and the general unscented transformation by virtue of the scaling parameter value. And resultantly, the number of sampling points, weights, code configuration and computation time are different. But there is no little information on the scaling parameter value or how this value influences the system performance. To analyze the unscented transformation with the various scaling parameters in this study, the experimental results under a wide range of operation condition have been demonstrated.
Practical Methodology of the Integrated Design and Power Control Unit for SHEV with Multiple Power Sources
Lee, Seongjun ; Kim, Jonghoon ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 353~360
DOI : 10.5370/JEET.2016.11.2.353
Series hybrid electric vehicles (SHEVs) having multiple power sources such as an engine- generator (EnGen), a battery, and an ultra-capacitor require a power control unit with high power density and reliable control operation. However, manufacturing using separate individual power converters has the disadvantage of low power density and requires a large number of power and signal cable wires. It is also difficult to implement the optimal power distribution and fault management algorithm because of the communication delay between the units. In order to address these concerns, this approach presents a design methodology and a power control algorithm of an integrated power converter for the SHEVs powered by multiple power sources. In this work, the design methodology of the integrated power control unit (IPCU) is firstly elaborately described, and then efficient and reliable power distribution algorithms are proposed. The design works are verified with product-level and vehicle-level performance experiments on a 10-ton SHEV.
A Design of Optimal Interval between Armatures in Long Distance Transportation PMLSM for End Cogging Force Reduction
Park, Eui-Jong ; Jung, Sang-Yong ; Kim, Yong-Jae ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 361~366
DOI : 10.5370/JEET.2016.11.2.361
Although the permanent magnet linear synchronous motor is a motor useful for transportation systems thanks to its high speed, high acceleration and deceleration, the linear motor generally has armatures installed on the full length of the transport path. It results in the increase in material costs and manufacturing time. As a means to solve this problem a stationary discontinuous armature system is suggested. However, it involves the following two issues. The first issue is it is impossible to control the mover in the section where any armature is not installed as armatures are distributed. The second one is increasing cogging force due to the ends of the armatures. Therefore, this study aims to solve these problems by adjusting intervals between armatures to control the mover anywhere, and to design the interval between armatures optimally to minimize the end cogging force. The suitable distance was deduced. It addressed the problems and showed suitability for long distance transportation PMLSM.
Cell Balancing Method in Flyback Converter without Cell Selection Switch of Multi-Winding Transformer
Kim, Jin-Woong ; Ha, Jung-Ik ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 367~376
DOI : 10.5370/JEET.2016.11.2.367
This paper presents a cell balancing method for a single switch flyback converter with a multi-winding transformer. The conventional method using a flyback converter with a multi-winding transformer is simple and easy to control, but the voltage of each secondary winding coil might be non-uniform because of the unequal effective turn-ratio. In particular, it is difficult to control the non-uniform effect using turn-ratios because secondary coil has a limited number of turns. The non-uniform secondary voltages disturb the cell balancing procedure and induce an unbalance in cell voltages. Individual cell control by adding a switch for each cell can reduce the undesirable effect. However, the circuit becomes bulky, resulting in additional loss. The proposed method here uses the conventional flyback converter with an adjustment made to the output filters of the cells, instead of the additional switch. The magnitude of voltage applied to a particular cell can be reduced or increased according to the adjusted filter and the selected switching frequency. An analysis of the conventional converter configuration and the filter design method reveals the possibility of adequate cell balancing control without any additional switch on the secondary side.
The Equilibrium Design of Radial Magnetic Force for Reduction of Vibration in IPM type BLDC Motor
Lee, Gyeong-Deuk ; Kim, Gyu-Tak ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 377~382
DOI : 10.5370/JEET.2016.11.2.377
In this paper, influence of vibration on cogging torque and Radial Magnetic Force(RMF) imbalance was investigated in the IPM type BLDC motor. Design of cogging torque reduction and the RMF equilibrium was proceed applied to Design of Experiment(DOE). Vibration test results, the RMF imbalance was confirmed that a significant impact of vibration.
Design Considerations of Resonant Network and Transformer Magnetics for High Frequency LLC Resonant Converter
Park, Hwa-Pyeong ; Ryu, Younggon ; Han, Ki Jin ; Jung, Jee-Hoon ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 383~392
DOI : 10.5370/JEET.2016.11.2.383
This paper proposes the design considerations of resonant network and transformer magnetics for 500 kHz high switching frequency LLC resonant converter. The high power density can be effectively achieved by adopting high switching frequency which allows small size passive components in the converter. The design methodology of magnetizing inductance is derived for zero voltage switching (ZVS) condition, and the design methodology of the transformer and output capacitance is derived to achieve high power density at high operating frequency. Moreover, the structure of transformer is analyzed to obtain the proper inductance value for high switching operation. To verify the proposed design methodology, simulation and experimental results will be presented including temperature of passive and active components, and power conversion efficiency to evaluate dominant power loss. In addition, the validity of magnetics design will be evaluated with operating waveforms of the prototype converter.
A Study on a Carrier Based PWM having Constant Common Mode Voltage and Minimized Switching Frequency in Three-level Inverter
Ahn, Kang-Soon ; Choi, Nam-Sup ; Lee, Eun-Chul ; Kim, Hee-Jun ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 393~404
DOI : 10.5370/JEET.2016.11.2.393
In this paper, a carrier-based pulse with modulation (PWM) strategy for three-phase three-level inverter is dealt with, which can keep the common mode voltage constant with minimized switching frequency. The voltage gain and the switching frequency in overall operating ranges including overmodulation are investigated and the analytic equations are presented. Finally, the leakage current reduction effect is confirmed by carrying out simulation and experiment. It will be pointed out that the leakage current cannot be perfectly eliminated because of the dead time.
Model Predictive Control for Shunt Active Power Filter in Synchronous Reference Frame
Al-Othman, A.K. ; AlSharidah, M.E. ; Ahmed, Nabil A. ; Alajmi, Bader. N. ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 405~415
DOI : 10.5370/JEET.2016.11.2.405
This paper presents a model predictive control for shunt active power filters in synchronous reference frame using space vector pulse-width modulation (SVPWM). The three phase load currents are transformed into synchronous rotating reference frame in order to reduce the order of the control system. The proposed current controller calculates reference current command for harmonic current components in synchronous frame. The fundamental load current components are transformed into dc components revealing only the harmonics. The predictive current controller will add robustness and fast compensation to generate commands to the SVPWM which minimizes switching frequency while maintaining fast harmonic compensation. By using the model predictive control, the optimal switching state to be applied to the next sampling time is selected. The filter current contains only the harmonic components, which are the reference compensating currents. In this method the supply current will be equal to the fundamental component of load current and a part of the current at fundamental frequency for losses of the inverter. Mathematical analysis and the feasibility of the suggested approach are verified through simulation results under steady state and transient conditions for non-linear load. The effectiveness of the proposed controller is confirmed through experimental validation.
Detection of Stator Winding Inter-Turn Short Circuit Faults in Permanent Magnet Synchronous Motors and Automatic Classification of Fault Severity via a Pattern Recognition System
CIRA, Ferhat ; ARKAN, Muslum ; GUMUS, Bilal ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 416~424
DOI : 10.5370/JEET.2016.11.2.416
In this study, automatic detection of stator winding inter-turn short circuit fault (SWISCFs) in surface-mounted permanent magnet synchronous motors (SPMSMs) and automatic classification of fault severity via a pattern recognition system (PRS) are presented. In the case of a stator short circuit fault, performance losses become an important issue for SPMSMs. To detect stator winding short circuit faults automatically and to estimate the severity of the fault, an artificial neural network (ANN)-based PRS was used. It was found that the amplitude of the third harmonic of the current was the most distinctive characteristic for detecting the short circuit fault ratio of the SPMSM. To validate the proposed method, both simulation results and experimental results are presented.
Torque Ripple Minimization of PMSM Using Parameter Optimization Based Iterative Learning Control
Xia, Changliang ; Deng, Weitao ; Shi, Tingna ; Yan, Yan ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 425~436
DOI : 10.5370/JEET.2016.11.2.425
In this paper, a parameter optimization based iterative learning control strategy is presented for permanent magnet synchronous motor control. This paper analyzes the mechanism of iterative learning control suppressing PMSM torque ripple and discusses the impact of controller parameters on steady-state and dynamic performance of the system. Based on the analysis, an optimization problem is constructed, and the expression of the optimal controller parameter is obtained to adjust the controller parameter online. Experimental research is carried out on a 5.2kW PMSM. The results show that the parameter optimization based iterative learning control proposed in this paper achieves lower torque ripple during steady-state operation and short regulating time of dynamic response, thus satisfying the demands for both steady state and dynamic performance of the speed regulating system.
Partial Discharge Process and Characteristics of Oil-Paper Insulation under Pulsating DC Voltage
Bao, Lianwei ; Li, Jian ; Zhang, Jing ; Jiang, Tianyan ; Li, Xudong ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 436~444
DOI : 10.5370/JEET.2016.11.2.436
Oil-paper insulation of valve-side windings in converter transformers withstand electrical stresses combining with AC, DC and strong harmonic components. This paper presents the physical mechanisms and experimental researches on partial discharge (PD) of oil-paper insulation at pulsating DC voltage. Theoretical analysis showed that the phase-resolved distributions of PDs generated from different insulated models varied as the increase of the applied voltages following a certain rule. Four artificial insulation defect models were designed to generate PD signals at pulsating DC voltages. Theoretical statements and experimental results show that the PD pulses first appear at the maximum value of the applied pulsating DC voltage, and the resolved PD phase distribution became wider as the applied voltage increased. The PD phase-resolved distributions generated from the different discharge models are also different in the phase-resolved distributions and development progress. It implies that the theoretical analysis is suitable for interpretation of PD at pulsating DC voltage.
Discharge Characteristics in Soils Subjected to Lightning Impulse Voltages
Kim, Seung Min ; Yoo, Yang-Woo ; Lee, Bok-Hee ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 446~454
DOI : 10.5370/JEET.2016.11.2.446
In this paper, we present experimental results of the soil discharge characteristics as a function of moisture content when a 1.2/50-㎲ lightning impulse voltage is applied. For this study, laboratory experiments were carried out based on factors affecting the transient behavior in soils. The electrical breakdown voltages in soils were measured for a 0-6% range of moisture content for sand and a 0 - 4% range of moisture content for gravel. A test cell with semi-spherical electrodes buried face-to-face in the middle of a cylindrical container was used. The distance separating the electrodes is 100 mm. As a result, the time-lag to breakdown in soils decreases as the amplitude of applied voltage increases. The time-lag to initiation of ionization streamer is decreased, with an increase in the moisture content. However, the formative time-lag is rarely changed. The behavior of soil discharges depend not only on the type of soil and its moisture content but also on the amplitude of the impulse voltage. When the test voltage is applied repeatedly, electrical breakdown occurs along different discrete paths, leading radially away from the injected electrode. i.e., the fact that the ionization streamers propagate in different paths from shot to shot was observed.
Analysis of Electron Transport Coefficients in Binary Mixtures of TEOS Gas with Kr, Xe, He and Ne Gases for Using in Plasma Assisted Thin-film Deposition
Tuan, Do Anh ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 455~462
DOI : 10.5370/JEET.2016.11.2.455
The electron transport coefficients in not only pure atoms and molecules but also in the binary gas mixtures are necessary, especially on understanding quantitatively plasma phenomena and ionized gases. Electron transport coefficients (electron drift velocity, density-normalized longitudinal diffusion coefficient, and density-normalized effective ionization coefficient) in binary mixtures of TEOS gas with buffer gases such as Kr, Xe, He, and Ne gases, therefore, was analyzed and calculated by a two-term approximation of the Boltzmann equation in the E/N range (ratio of the electric field E to the neutral number density N) of 0.1 - 1000 Td (1 Td = 10
). These binary gas mixtures can be considered to use as the silicon sources in many industrial applications depending on mixture ratio and particular application of gas, especially on plasma assisted thin-film deposition.
D-CRLH Based Band Rejection Filter using a Concavo-Convex Coupled CPW Transmission Line
Seo, Soo-Duk ; Cho, Hak-Rae ; Yang, Doo-Yeong ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 463~469
DOI : 10.5370/JEET.2016.11.2.463
In this paper, the use of a dual composite right/left-handed coplanar waveguide (CPW) transmission line is proposed for the design of a band rejection filter. The notch property of the filter is achieved by combining the convex signal line with the shorted concave meander line, and the equivalent circuit model is extracted from the geometry of the unit cell for organizing the band rejection property. Then the equivalent parameters of the unit cell are analyzed to identify those behaviors. And the dispersion characteristics and energy distributions are simulated. In the end, the band rejection filter is manufactured by cascading two proposed unit cells. We show that the measurement result for the resonant frequency demonstrates good agreement with the simulation result and the band rejection filter provides a rejection performance of 17.5 dB at the stopband frequency ranging from 869 MHz to 894 MHz.
The Energy Saving for Separately Excited DC Motor Drive via Model Based Method
Udomsuk, Sasiya ; Areerak, Kongpol ; Areerak, Kongpan ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 470~479
DOI : 10.5370/JEET.2016.11.2.470
The model based method for energy saving of the separately excited DC motor drive system is proposed in the paper. The accurate power loss model is necessary for this method. Therefore, the adaptive tabu search algorithm is applied to identify the parameters in the power loss model. The field current values for minimum power losses at any load torques and speeds are calculated by the proposed method. The rule based controller is used to control the field current and speed of the motor. The experimental results confirm that the model based method can successfully provide the energy saving for separately excited DC motor drive. The maximum value of the energy saving is 48.61% compared with the conventional drive method.
Interferer Aware Multiple Access Protocol for Power-Line Communication Networks
Yoon, Sung-Guk ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 480~489
DOI : 10.5370/JEET.2016.11.2.480
Hidden station problem can occur in power-line communication (PLC) networks. A simple solution to the problem has been proposed to use request-to-send (RTS)/clear-to-send (CTS) exchange, but this approach cannot solve the hidden station problem perfectly. This paper revisits the problem for PLC networks and designs a protocol to solve it. We first analyze the throughput performance degradation when the hidden station problem occurs in PLC networks. Then, we propose an interferer aware multiple access (IAMA) protocol to enhance throughput and fairness performances, which uses unique characteristics of PLC networks. Using the RTS/CTS exchange adaptively, the IAMA protocol protects receiving stations from being interfered with neighboring networks. Through extensive simulations, we show that our proposed protocol outperforms conventional random access protocols in terms of throughput and fairness.
Paper Machine Industrial Analysis on Moisture Control Using BF-PSO Algorithm and Real Time Implementation Setup through Embedded Controller
Senthil Kumar, M. ; Mahadevan, K. ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 490~498
DOI : 10.5370/JEET.2016.11.2.490
Proportional Integral Derivative (PID) controller tuning is an area of interest for researchers in many areas of science and engineering. This paper presents a new algorithm for PID controller tuning based on a combination of bacteria foraging and particle swarm optimization. BFO algorithm has recently emerged as a very powerful technique for real parameter optimization. To overcome delay in an optimization, combine the features of BFOA and PSO for tuning the PID controller. This new algorithm is proposed to combine both the algorithms to get better optimization values. The real time prototype model of paper machine is designed and controlled by using PIC microcontroller embedded with the programming in C language.
Medical Image Compression using Adaptive Subband Threshold
Vidhya, K ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 499~507
DOI : 10.5370/JEET.2016.11.2.499
Medical imaging techniques such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT) and Ultrasound (US) produce a large amount of digital medical images. Hence, compression of digital images becomes essential and is very much desired in medical applications to solve both storage and transmission problems. But at the same time, an efficient image compression scheme that reduces the size of medical images without sacrificing diagnostic information is required. This paper proposes a novel threshold-based medical image compression algorithm to reduce the size of the medical image without degradation in the diagnostic information. This algorithm discusses a novel type of thresholding to maximize Compression Ratio (CR) without sacrificing diagnostic information. The compression algorithm is designed to get image with high optimum compression efficiency and also with high fidelity, especially for Peak Signal to Noise Ratio (PSNR) greater than or equal to 36 dB. This value of PSNR is chosen because it has been suggested by previous researchers that medical images, if have PSNR from 30 dB to 50 dB, will retain diagnostic information. The compression algorithm utilizes one-level wavelet decomposition with threshold-based coefficient selection.
Golf Green Slope Estimation Using a Cross Laser Structured Light System and an Accelerometer
Pham, Duy Duong ; Dang, Quoc Khanh ; Suh, Young Soo ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 508~518
DOI : 10.5370/JEET.2016.11.2.508
In this paper, we propose a method combining an accelerometer with a cross structured light system to estimate the golf green slope. The cross-line laser provides two laser planes whose functions are computed with respect to the camera coordinate frame using a least square optimization. By capturing the projections of the cross-line laser on the golf slope in a static pose using a camera, two 3D curves’ functions are approximated as high order polynomials corresponding to the camera coordinate frame. Curves’ functions are then expressed in the world coordinate frame utilizing a rotation matrix that is estimated based on the accelerometer’s output. The curves provide some important information of the green such as the height and the slope’s angle. The curves estimation accuracy is verified via some experiments which use OptiTrack camera system as a ground-truth reference.
Fast Quadtree Based Normalized Cross Correlation Method for Fractal Video Compression using FFT
Chaudhari, R.E. ; Dhok, S.B. ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 519~528
DOI : 10.5370/JEET.2016.11.2.519
In order to achieve fast computational speed with good visual quality of output video, we propose a frequency domain based new fractal video compression scheme. Normalized cross correlation is used to find the structural self similar domain block for the input range block. To increase the searching speed, cross correlation is implemented in the frequency domain using FFT with one computational operation for all the domain blocks instead of individual block wise calculations. The encoding time is further minimized by applying rotation and reflection DFT properties to the IFFT of zero padded range blocks. The energy of overlap small size domain blocks is pre-computed for the entire reference frame and retaining the energies of the overlapped search window portion of previous adjacent block. Quadtree decompositions are obtained by using domain block motion compensated prediction error as a threshold to control the further partitions of the block. It provides a better level of adaption to the scene contents than fixed block size approach. The result shows that, on average, the proposed method can raise the encoding speed by 48.8 % and 90 % higher than NHEXS and CPM/NCIM algorithms respectively. The compression ratio and PSNR of the proposed method is increased by 15.41 and 0.89 dB higher than that of NHEXS on average. For low bit rate videos, the proposed algorithm achieve the high compression ratio above 120 with more than 31 dB PSNR.
A Novel Approach for Blind Estimation of Reverberation Time using Gamma Distribution Model
Hamza, Amad ; Jan, Tariqullah ; Jehangir, Asiya ; Shah, Waqar ; Zafar, Haseeb ; Asif, M. ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 529~536
DOI : 10.5370/JEET.2016.11.2.529
In this paper we proposed an unsupervised algorithm to estimate the reverberation time (RT) directly from the reverberant speech signal. For estimation process we use maximum likelihood estimation (MLE) which is a very well-known and state of the art method for estimation in the field of signal processing. All existing RT estimation methods are based on the decay rate distribution. The decay rate can be obtained either from the energy envelop decay curve analysis of noise source when it is switch off or from decay curve of impulse response of an enclosure. The analysis of a pre-existing method of reverberation time estimation is the foundation of the proposed method. In one of the state of the art method, the reverberation decay is modeled as a Laplacian distribution. In this paper, the proposed method models the reverberation decay as a Gamma distribution along with the unification of an effective technique for spotting free decay in reverberant speech. Maximum likelihood estimation technique is then used to estimate the RT from the free decays. The method was motivated by our observation that the RT of a reverberant signal when falls in specific range, then the decay rate of the signal follows Gamma distribution. Experiments are carried out on different reverberant speech signal to measure the accuracy of the suggested method. The experimental results reveal that the proposed method performs better and the accuracy is high in comparison to the state of the art method.
An AP Selection Criteria for Enhanced Indoor Positioning using IEEE 802.11 RSSI Measurements and AP Configuration Information
Hwang, Jun Gyu ; Lee, Kwang Eog ; Park, Joon Goo ;
Journal of Electrical Engineering and Technology, volume 11, issue 2, 2016, Pages 537~542
DOI : 10.5370/JEET.2016.11.2.537
The demand for LBS (Location Based Services) is increasing in the development of communication and mobile technologies. Positioning technology is a core technology for LBS, because LBS is based on a position of each device or user. But positioning technology especially for indoor environments is getting a lot of attention. Indoor positioning errors usually occur seriously in indoor environments where APs (Access Points) are set in a very concentrated and complex arrangement. In order to reduce indoor positioning errors, we adopt DOP (Dilution of Precision) which reflects an APs configuration information. In this paper, we propose an enhanced indoor positioning method using IEEE 802.11 RSSI measurements and AP configuration information.