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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 59, Issue 12 - Dec 2010
Volume 59, Issue 11 - Nov 2010
Volume 59, Issue 10 - Oct 2010
Volume 59, Issue 9 - Sep 2010
Volume 59, Issue 8 - Aug 2010
Volume 59, Issue 7 - Jul 2010
Volume 59, Issue 6 - Jun 2010
Volume 59, Issue 5 - May 2010
Volume 59, Issue 4 - Apr 2010
Volume 59, Issue 3 - Mar 2010
Volume 59, Issue 2 - Feb 2010
Volume 59, Issue 1 - Jan 2010
Selecting the target year
Evaluation of Optimal Transfer Capability in Power System Interconnection
Son, Hyun-Il ; Bae, In-Su ; Jeon, Dong-Hoon ; Kim, Jin-O ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 679~685
As the electrical power industry is restructured, the electrical power exchange is becoming extended. One of the key information used to determine how much power can be transferred through the network is known as available transfer capability (ATC). To calculate ATC, traditional deterministic approach is based on the severest case, but the approach has the complexity of procedure. Therefore, novel approach for ATC calculation is proposed using cost-optimization method, well-being method and risk-benefit method in this paper. This paper proposes the optimal transfer capability of HVDC system between mainland and a separated island in Korea through these three methods. These methods will consider production cost, wheeling charge through HVDC system and outage cost with one depth (N-1 contingency).
Quasi-Steady-State Analysis on the Effect of the STATCOM on FRT Performance of Fixed Speed Wind Turbines
Ahn, Seon-Ju ; Hwang, Pyeong-Ik ; Nam, Soon-Ryul ; Kang, Sang-Hee ; Moon, Seung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 686~692
This paper analyzes the effect of the STATCOM on the improvement of the Fault Ride Through (FRT) capability of the fixed speed wind turbines(FSWTs). The steady-state models of the wind farm components, such as induction generator, capacitor bank, and the STATCOM, are developed based on the simplified equivalent circuit. Especially, the STATCOM is modeled as a controllable current source and a method that analytically determines the magnitude of the injection current is developed. For the quasi-steady-state(QSS) analysis, the steady-state model of the generator and STATCOM are merged with the dynamic model of drive train. The QSS simulation with the STATCOM shows that the STATCOM can enhance the FRT performance by improving the
characteristics of the FSWTs.
Analysis for Insulating Degradation Characteristics with Aging Time for Oil-filled Transformers and/or Correlation between using Linear Regression Method
Lee, Seung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 693~699
General transformer's life is known as paper insulation' life. If a transformer is degraded by these aging factors, it is known that electrical, mechanical and chemical characteristics for transformer's oil-paper are changed. When the kraft paper is aged, the cellulose polymer chains break down into shorter lengths. It causes decrease in both tensile strength and degree of polymerization of paper insulation. The paper breakdown is accompanied by an increase in the content of furanic compounds within the dielectric liquid. In this paper it is aimed at analysis on correlation between aging characteristics for insulating diagnosis of thermally aged paper. For investigating the accelerated aging process of oil-paper samples accelerating aging cell was manufactured for estimating variation of paper insulation during 500 hours at
temperature. To derive the results, it was performed analysis such as tensile strength(TS), depolymerization(DP), dielectric strength(DS), relative permittivity, water content(WC) and furan compound(FC) for aged paper. Also for analyzing correlation between insulating degradation characteristics, we used linear regression method. As as results of linear regression analysis, there was a close correlation between TS and DP. WC, FC. But dielectric strength was a weak correlation with aging time.
Impact of Carbon Costs on Wholesale Electricity Market
Kim, Wook ; Park, Jong-Bae ; Lee, Joo-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 700~706
Carbon costs, either in the form of a carbon tax or through permit prices in an emissions trading scheme, would ultimately be reflected in higher electricity prices. This price "pass-through" is very critical to the effective design of new policies to curb the amount of carbon emissions. This paper sets out in a structured way the factors that determine price pass-through and how carbon costs would impact on the electricity market and the existing coal-fired power plants. It is shown that pass-through can vary drastically if the underlying dispatch potential of generators varies significantly across alternative emissions reduction scenarios. It can also vary depending on the availability of competing cleaner forms of generation. Pass-through as a measure of business performance is therefore hard to generalize across different circumstances and should be interpreted carefully.
Power Balancing Strategy in the Microgrid During Transient
Seo, Jae-Jin ; Lee, Hak-Ju ; Jung, Won-Wook ; Won, Dong-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 707~714
When problems such as line fault, breakdown of a substation or a generator, etc. arise on the grid, the Microgrid is designed to be separated or isolated from the grid. Most existing DGs(Distributed Generators) in distribution system use rotating machine. However, new DGs such as micro gas turbine, fuel cell, photo voltaic, wind turbine, etc. will be interfaced with the Microgrid through an inverter. So the Microgrid may have very lower inertia than the conventional distribution system. By the way, the rate of change of frequency depends on the inertia of the power system. Moreover, frequency has a strong coupling with active power in power system. Because the frequency of the Microgrid may change rapidly and largely during transient, appropriate and fast control strategy is needed for stable operation of the Microgrid. Therefore, this paper presents a power balancing strategy in Microgrid during transient. Despite of strong power or frequency excursions, power balancing in the Microgrid can be maintained.
Design and Characteristic Analysis of Hybrid-Type Levitation and Propulsion Device for High-Speed Maglev Vehicle
Cho, Han-Wook ; Kim, Chang-Hyun ; Han, Hyung-Suk ; Lee, Jong-Min ; Kim, Bong-Sup ; Kim, Dong-Sung ; Lee, Young-Sin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 715~721
This paper deals with the design and characteristic analysis of electro-magnet/permanent-magnet (EM-PM) hybrid levitation and propulsion device for high-speed magnetically levitated (maglev) vehicle. The machine requires PMs with high coercive force in order to levitate the vehicle by only PMs, and propulsion force is supplied by long-stator linear synchronous motor (LSM). The advantages of this configuration are an increasing levitation airgap length and decreasing total weight of the vehicle, because of the zero-power levitation control. Several design considerations such as machine structure, manufacturing, and control strategy are described. Moreover, the levitation and propulsion device for high-speed maglev vehicle has been designed and analyzed usign the electromagnetic circuit and FE analysis. In order to verify the design scheme and feasibility of maglev application, 3-DOF static force test set is implemented and tested. The obtained experimental data using the static tester shows the validity of the design and analysis approaches.
Inductance Estimation of Permanent Magnet Type Transverse Flux Rotating Motor Using Dynamic-Simulation
Kim, Kwang-Woon ; Kim, Ji-Won ; Jung, Yeon-Ho ; Lee, Ji-Young ; Kang, Do-Hyun ; Chang, Jung-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 722~727
This paper presents Dynamic-Simulation to estimate the inductance of a permanent magnet type transverse flux rotating motor by applying the real-time parameter estimation theory. As transverse flux rotating motor has the complex structure, it can be happen to some errors between real value and designed one with respect to the inductance. To reduce this kinds of errors, the real-time parameter estimation theory was applied to dynamic-simulation. And then, By comparing the estimated inductance and designed one, it is realized that the real-time parameter estimation theory can be applied in the permanent magnet type transverse flux rotating motor.
A Study of the Method for External Noise Shielding using the GIS UHF Sensor Module Applied to the Partial Discharge Signal Sensitivity and Method of Frequency Transforming in the Internal GIS
Lee, Seung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 728~732
GIS(Gas insulated switching gear) is power equipment with excellent dielectric strength and is economy merit in high confidence and stability. Recently, because equipment of GIS was occurring problem of confidence used for a long time, partial discharge on-line diagnosis systems have been importantly recognized. Partial discharge (PD) detection is an effective means for monitoring and evaluation of dielectric condition of gas insulated system (GIS). The ultra-high-frequency (UHF) PD detection technique can detect and locate the PD sources inside GIS by detecting electromagnetic wave emitted from PD source. Therefore, real-time diagnostic system using UHF detection method has been developed for this application is being expanded gradually. However, the signal of partial discharge occurring in SF6 gas is very weak and susceptible to external noises which mainly consist of PD in air. Thus, it is important to distinguish the PD in SF6 gas more sensitively from the external noises. Unfortunately, these external noise signals and the partial discharge signals have very similar characteristics. Therefore, to solve this problem, we need the signal processing method for distinguish partial discharge signals with external noise signals for improvement of SNR(signal to noise ratio) and sensitivity. In this paper, we proposed internal signal processing method for removing external noise signals with built-in pre.amplifier and frequency conversion circuit.
Development of Automatic Transferring Motor Driver for a Two-Motors-Driven Electrical Scooter
Chung, Dae-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 733~739
We developed to have an automatic transferring function of a two-motors-driven electrical scooter for women or seniors to use conveniently it since it has been previously to operate it in manual only. The function would be implemented by using master and slave micro-control units(MCU) in the system with the given input and output signals. The simulation and test of the system results show that the transition conditions of either higher accelerating speed and/or higher torque are demonstrated at the worst conditions, which means that the transition points might be set either at the 70% of accelerating speed or from the 100% of load torque. The developed equipment is very useful and has good performance in the real test and would be used for top brand and might be applicable to any other types of green cars.
High-Performance Sensorless-Control of PMSM Using Back-EMF and Reactive Power
Lee, Guen-Bo ; Kwon, Young-Ahn ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 740~742
This paper investigates a high-performance strategy for speed sensorless control of a permanent magnet synchronous motor. Two speed sensorless controls using back-EMF and reactive power are analyzed in this paper, and these two speed estimations are appropriately applied according to the steady and transient states for a high-performance sensorless control. The proposed sensorless control algorithm has a better performance compared to the conventional control algorithms.
Electron Emission Properties of Hetero-Junction Structured Carbon Nanotube Microtips Coated With BN And CN Thin Films
Noh, Young-Rok ; Kim, Jong-Pil ; Park, Jin-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 743~748
Boron nitride (BN) and carbon nitride (CN) films, which have relatively low work functions and commonly exhibit negative electron affinity behaviors, were coated on carbon nanotubes (CNTs) by magnetron sputtering. The CNTs were directly grown on metal-tip (tungsten, approximately 500nm in diameter at the summit part) substrates by inductively coupled plasma-chemical vapor deposition (ICP-CVD). The variations in the morphology and microstructure of CNTs due to coating of the BN and CN films were analyzed by field-emission scanning electron microscopy (FE-SEM). The energy dispersive x-ray (EDX) spectroscopy and Raman spectroscopy were used to identify the existence of the coated layers (CN and BN) on CNTs. The electron-emission properties of the BN-coated and CN-coated CNT-emitters were characterized using a high-vacuum field emission measurement system, in terms of their maximum emission currents (
) at 1kV and turn-on voltage (
) for approaching
. The results showed that the
current was significantly increased and the
voltage were remarkably reduced by the coating of CN or BN films. The measured values of
were as follows;
-500V for the 5nm CN-coated emitter and
-540V for the 2nm BN-coated emitter, respectively, while the
of the as-grown (i.e., uncoated) emitter was
-620V. In addition, the CNT emitters coated with thin CN or BN films also showed much better long-term (up to 25h) stability behaviors in electron emission, as compared with the conventional CNT emitter.
Characterizations of Surface Textured Silicon Substrated by XeF
Kim, Seon-Hoon ; Ki, Hyun-Chul ; Kim, Doo-Gun ; Na, Yong-Beom ; Kim, Nam-Ho ; Kim, Hwe-Jong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 749~753
We investigated the haze and the surface roughness of textured Si substrates etched by
etching system with the etching parameters of
pressure, etching time, and etching cycle. Here the haze was obtained as a function of wavelength from the measured reflectance. The haze of textured Si substrates was strongly affected by the etching parameter of etching cycle. The surface roughness of textured Si substrates was calculated with the haze and the scalar scattering theory at the wavelength of 800 nm. Then, the surface roughness was compared with that measured by atomic force microscope. The surce roughness obtained by two methods was changed with the similar tendency n terms of
A Study on the Fabrication of Dye-Sensitized Solar Cells Consisting of Ti Electrodes by Electron-beam Evaporation Method
Kim, Yun-Gi ; Shim, Choung-Hwan ; Kim, Hyun-Gyu ; Sung, Youl-Moon ; Kim, Dong-Hyun ; Lee, Hae-June ; Park, Chung-Hoo ; Lee, Ho-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 754~758
In general, Dye-sensitized Solar Cells(DSCs) consist of the nanocrystalline titanium dioxide(
) layer which is fabricated on a transparent conductive oxide(TCO) layer such as
glass, a dye adhered to the
, an electrolyte solution and platinum-coated TCO. Among these components, two TCO substrates are estimated to be about 60% of the total cost of the DSCs. Currently novel TCO-less structures have been investigated in order to reduce the cost. In this study, TCO-less DSCs consisting of titanium electrodes were investigated. The titanium electrode is deposited on top of the porous
layer using electron-beam evaporation process. The porosity of the titanium electrode was found out by the SEM analysis and dye adhesion. As a result, when the thickness of the titanium electrode increased, the surface resistance decreased and the conversion efficiency increased relatively.
Wavelet-Based Flashover Prediction Using High-Frequency Components
Song, Young-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 759~761
In order to monitor operating performance of contaminated outdoor insulators, a wavelet-based flashover prediction method is proposed. In most cases, the low-frequency components, namely, fundamental,
harmonic components have been mainly used for the sake of the spectral analysis of the leakage current. However, in this paper, the detail coefficients of wavelet transform representing high-frequency components are used as important information to predict a flashover in the contaminated insulator. Experimental results verify that the proposed method has a superior capability for flashover prediction.
A Study on Characteristics of Light Triggered Thyristor for Pulsed Power Application
Lee, Byung-Ha ; Kim, Jin-Sung ; Kim, Young-Bae ; Cha, Han-Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 762~767
This paper describes characteristic of a light triggered thyristor investigated by experiment to adopt it into a main switch of a pulsed power unit. Triggering principle of the light triggered thyristor are referred with its structure and equivalent circuit. Operational principle and simulation result of a capacitive pulsed power circuit are explained. A variety of triggering conditions of triggering circuit and characteristics on turn-on, turn-off, voltage dividing in series operation, overvoltage protection function of the light triggered thyristor are investigated by experiments. Experimental result of 40 kJ pulsed power unit using the light triggered thyristor is presented.
A Study on an Optimal Design of a Triple-band PIFA using the Evolution Strategy
Ko, Jae-Hyeong ; Kim, Koon-Tae ; Kim, Kyong-Ah ; Kim, Hyeong-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 768~773
In this paper, we study on an optimal design of a triple-band PIFA (Planar Inverted-F Antenna) of 433 MHz, 912 MHz and 2.45 GHz by using evolution strategy. Generally, the resonant frequency of the PIFA is determined by the width and length of a U-type slot used. However the resonant frequencies of the multiple U slots are varied by the mutual effect of the slots. Thus the optimal width and length of U-type slots are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The resonant frequencies of initial model are 439.5 MHz, 981.5 MHz and 2.563 GHz. However, the resonant frequencies of the triple-band PIFA yielded by the optimal design program are 430.5 MHz, 907 MHz and 2.4515 GHz. Measured resonant frequencies are 433.5 MHz, 905.5 MHz and 2.454GHz, which show a good agreement with the simulation results.
The Preliminary EMC Analysis Between the COMS RE and the GEO Launch Vehicles RS
Kim, Eui-Chan ; Lee, Seung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 774~778
In this paper, the preliminary EMC analysis process between the Communication, Ocean and Meteorological Satellite (COMS) and the Geostationary Earth Orbit (GEO) launch vehicles in the frequency range is described. The considered launch vehicles are Arian Ⅴ, Sea Launch, Land Launch, Atlas III&Ⅴ, Delta IV, Proton M/breeze M, Soyuz, H II-Aa. The launch vehicle Radiated Susceptibility (RS) specifications have been compared to COMS satellite Radiated Emission (RE) limits. The COMS Radiated Emission (RE) level is determined by calculating the radiated field equal to the quadratic sum of radiated emissions of each equipment switched "ON" during launch. As a result, The RS requirements of Arian V, Atlas III&V and Delta IV lauchers are compliant with COMS RE limits. The negative margins appear between the others launch vehicle RS (Sea Launch, Land Launch, Proton M/Breeze M, Soyuz and H II-A) and COMS RE. Then, if the launchers that have negative margin were chosen by the customer, The EMC tests should be performed at satellite level in order to demonstrate the compatibility with respect to launch vehicles requirements.
Classification and recognition of electrical tracking signal by means of LabVIEW
Kim, Dae-Bok ; Kim, Jung-Tae ; Oh, Sung-Kwun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 779~787
In this paper, We introduce electrical tracking generated from surface activity associated with flow of leakage current on insulator under wet and contaminated conditions and design electrical tracking pattern recognition system by using LabVIEW. We measure the leaking current of contaminated wire by using LabVIEW software and the NI-c-DAQ 9172 and NI-9239 hardware. As pattern recognition algorithm and optimization algorithm for electrical tracking system, neural networks, Radial Basis Function Neural Networks(RBFNNs) and particle swarm optimization are exploited. The designed electrical tracking recognition system consists of two parts such as the hardware part of electrical tracking generator, the NI-c-DAQ 9172 and NI-9239 hardware and the software part of LabVIEW block diagram, LabVIEW front panel and pattern recognition-related application software. The electrical tracking system decides whether electrical tracking generate or not on electrical wire.
Delay-dependent and Parameter-dependent Robust Stability for Discrete-time Delayed Uncertain Singular Systems
Kim, Jong-Hae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 788~792
The problem of delay-dependent and parameter-dependent robust stability condition for discrete-time uncertain singular systems with polytopic uncertainty and interval time-varying delay is considered. A new robust stability condition based on parameter-dependent Lyapunov function is derived in terms of LMI (linear matrix inequality). Moreover, the proposed robust stability condition is a general condition for both singular and non-singular systems. A numerical example is presented to demonstrate the effectiveness of the proposed method.
A Method of Selecting Filter Coefficient for Robust Data to Clock Equalizer in Optical Disc Drive
Yeom, Dong-Hae ; Kim, Jin-Kyu ; Joo, Young-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 793~796
The equalizer compensates a signal distorted by transmission lines and amplifying stages, so the signal can have uniform characteristics over all frequency range. The equalizer in ODD(Optical Disc Drive) improves the stability of the extracted clock from a received signal and the readability of an inserted disc by suppressing noise and ISI(Inter-Symbol Inference). The length of marks-spaces and track pitch on discs becomes shorter as the recording density of an optical media is higher, which causes noise and ISI. And, the sensitivity about the fluctuation of physical systems is higher as the optical devices become more complicate. This paper proposes a method to select the coefficient of built-in equalizer of ODD in order to maintain the quality of signals against noise and ISI caused by system fluctuation.
Nonlinear Controller Design of Active Magnetic Bearing Systems Based on Polytopic Quasi-LPV Models
Lee, Dong-Hwan ; Park, Jin-Bae ; Jeong, Hyun-Suk ; Joo, Young-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 797~802
In this paper, a systematic procedure to design a nonlinear controller for nonlinear active magnetic bearing (AMB) systems is presented. To do this, we effectively convert the AMB system into a polytopic quasi-linear parameter varying (LPV) system, which is a representation of nonlinear state-space models and is described by the convex combination of a set of precisely known vertices. Unlike the existing quasi-LPV systems, the nonlinear weighting functions, which construct the polytopic quasi-LPV model of the AMB system by connecting the vertices, include not only state variables but also the input ones. This allows us to treat the input nonlinearity effectively. By means of the derived polytopic quasi-LPV model and linear matrix inequality (LMI) conditions, nonlinear controller that stabilizes the AMB system is obtained. The effectiveness of the proposed controller design methodology is finally demonstrated through numerical simulations.
Smooth Path Planning Method for Autonomous Mobile Robots Using Cardinal Spline
Yoon, Hee-Sang ; Park, Tae-Hyoung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 803~808
We propose a smooth path planning method for autonomous mobile robots. Due to nonholonomic constraints by obstacle avoidance, the smooth path planning is a complicated one. We generate smooth path that is considered orientation of robot under nonholonomic constraints. The proposed smooth planning method consists of two steps. Firstly, the initial path composed of straight lines is obtained from V-graph by Dijkstra's algorithm. Then the initial path is transformed by changing the curve. We apply the cardinal spline into the stage of curve generation. Simulation results show a performance of proposed smooth path planning method.
Development of Conversion Tools from V2 to V3 based on caAdapter
Um, Ki-Sung ; Kim, Hwa-Sun ; Hong, Hae-Sook ; Cho, Hune ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 809~813
Although the goals of HL7 Version 2(V2) and Version 3(V3) are identical, the concepts of the implementation and technological basis are different; this makes their versions inconvertible. This problem interrupts technological innovation advanced from V2 to V3 and has been raised as a new type of barrier in the field of medical information system. This study intends to develop software to convert V2 to V3 which can be utilized in the actual medical environment. Since it is practically difficult to develop the whole tools that automatically change total V2 messages into V3 messages, this article has designed, implemented, and tested the software that allows mapping between V2 and V3 which function as tools. In order to test this program, it has used ADT^A03 of five V2 messages to generate V3 messages. It is expected that the result of this research will be one of the new methods allowing conversion between V2 and V3.
Power Transmission Mechanism and Data Communication of the Dosimeter using Contactless Powerless Transmission
Lee, Seung-Min ; Chung, Sung-In ; Lee, Heung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 814~819
This study proposes the antenna circuit design for the transmitting wireless power, the development of the RF non-contact type Dosimeter. That is, the study designed the optimization and numerical analysis of the antenna circuit for the antenna design of 13.56MHz over the frequency bands for transmitting wireless power. We studied the needed items in the existing RF type Dosimeter with battery to implement the wireless power non-contact Dosimeter within the battery. We compared to the real measurement value as calculating the value of the inductance and capacitance through the numerical analysis for the antenna LC resonance using the theory of the electromagnetic induction method. This method to drive low power is designed to simplify the circuit and to improve the efficiency of the rectifier. We convince our research contributes not only to understand the simplified circuit and miniaturization, but also to help the design and application technology of the wireless power transmit system which is received power supply with wireless.
QoS aware Multi-class scheduler in WiMAX System
Lee, Ju-Hyeon ; Park, Hyung-Kun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 820~822
Mobile WiMAX system provides various classes of traffic such as real-time and non-realtime services. These services have different QoS requirements and the QoS aware scheduling has been an important issue. Although many of scheduling algorithms for various services in OFDMA system have been proposed, it is needed to be modified to be applied to Mobile WiMAX system. Since Mobile WiMAX supports five kinds of service classes, it is important to take QoS characteristics of each class into consideration. In this paper, we propose an efficient packet scheduling algorithm to support QoS of each class. Proposed scheme selects a service class first considering QoS Characteristics of each class and choose an appropriate user in the selected class. Simulation results show that the proposed algorithm has better performance than the other algorithm.
A Study of Osteoporosis Prediction using Morphological Measuring of Proximal Femoral Part and Trabecular Characteristics Based on Femoral Radiographic Image
Kim, Sung-Min ; Roh, Seung-Gyu ; Ro, Yong-Man ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 823~830
This study was designed to examine the morphological measurement and characteristics of trabecullae based on femoral radiographic image for prediction of osteoporosis. Study subjects were 34 females (average age of 62.1 years) and 6 males (average age of 60.1 years), they were categorized into normal group and osteoporosis group in accordance with the T-score value. Measurement of the bone density of femoral bone was measured with DEXA(Dual Energy X-ray absorptiometry). ROI(Region of interests) was selected on femoral neck and trochanter. Characteristics of trabecullae was analyzed by using the skeletonization analysis of trabecular image. Morphological measurement was analyzed through femoral radiographic image in order to examine the correlation with osteoporosis. The result demonstrated statistically significant correlation between neck cortical thickness, shaft width, shaft cortical thickness, periphery, mean gray level and trabeculae area with BMD average (T-score) of femoral part. The results show that morphological measurement and characteristics of trabecullae based on femoral radiographic images for osteoporosis prediction could be effective.
A Study on Development of a Hearing Impairment Simulator considering Frequency Selectivity and Asymmetrical Auditory Filter of the Hearing Impaired
Joo, Sang-Ick ; Kang, Hyun-Deok ; Song, Young-Rok ; Lee, Sang-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 4, 2010, Pages 831~840
In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity and asymmetrical auditory filter of the hearing impaired, and we verified the reduced frequency selectivity and asymmetrical auditory filter affected in speech perception through experiments. The reduced frequency selectivity has made embodied by spectral smearing using LPC(linear prediction coding). The shapes of auditory filter are asymmetrical different with each center frequency. Hearing impaired person which has hearing loss was differently changed with that of normal hearing people and it has different value for speech of quality through auditory filter. The experiments confirmed subjective test and objective test. The subjective experiments are composed of 4 kinds of tests: pure tone test, SRT(speech reception threshold) test, and WRS(word recognition score) test without spectral smearing, and WRS test with spectral smearing. The experiment of the hearing impairment simulator was performed from 9 subjects who have normal ears. The amount of spectral smearing was controlled by LPC order. The asymmetrical auditory filter of proposed hearing impairment simulator was simulated and then some tests to estimate the filter's performance objectively were performed. The objective experiment as simulated auditory filter's performance evaluation method used PESQ(perceptual evaluation of speech quality) and LLR(log likelihood ratio) for speech through auditory filter. The processed speech was evaluated objective speech quality and distortion using PESQ and LLR value. When hearing loss processed, PESQ and LLR value have big difference according to asymmetrical auditory filter in hearing impairment simulator.