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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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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 57, Issue 12 - Dec 2008
Volume 57, Issue 11 - Nov 2008
Volume 57, Issue 10 - Oct 2008
Volume 57, Issue 9 - Sep 2008
Volume 57, Issue 8 - Aug 2008
Volume 57, Issue 7 - Jul 2008
Volume 57, Issue 6 - Jun 2008
Volume 57, Issue 5 - May 2008
Volume 57, Issue 4 - Apr 2008
Volume 57, Issue 3 - Mar 2008
Volume 57, Issue 2 - Feb 2008
Volume 57, Issue 1 - Jan 2008
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Stability Analysis of Jeju Power System with Wind Turbine Generators and HVDC
Kim, Do-Hyung ; Kim, Jae-Eon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1897~1904
In this paper, the method for effective stability analysis of Jeju power system in 2011 is proposed. The stability analysis of Jeju power system was carried out by using proposed method In case of Jeju power system with wind turbine generators or without wind turbine generators, including CSC HVDC or VSC HVDC. The steady-state stability is validated by SCR and ESCR, PV curve, QV curve. And the transient stability is analyzed by CCT(Critical Clearing Time). VSC HVDC has more advantages than CSV HVDC on the stability. Also, Jeju power system without wind turbine generators has more advantages than Jeju power system with Wind Turbine Generators on the stability.
Reliability Analysis of Catenary of Electric Railway by using FTA
Ku, Bon-Hui ; Cha, Jun-Min ; Kim, Hyung-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1905~1909
As catenary supply electric power directly to the railway system, it is very important to prevent an accident of a catenary for appropriate train operations. This paper analyzed the outage data for British catenary safety analysis report and Korean data to compare the reliability of the railway systems. The analyzed data were applied to Fault Tree Analysis(FTA) algorithm to calculate the reliability indices of a railway system. Failure rate of an electric railway system through FTA were calculated for each element and the entire railway system. The reliability indices can be used to determine the eqipment to be replaced for the entire system reliability improvement.
Spatio-temporal Load Analysis Model for Power Facilities using Meter Reading Data
Shin, Jin-Ho ; Kim, Young-Il ; Yi, Bong-Jae ; Yang, Il-Kwon ; Ryu, Keun-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1910~1915
The load analysis for the distribution system and facilities has relied on measurement equipment. Moreover, load monitoring incurs huge costs in terms of installation and maintenance. This paper presents a new model to analyze wherein facilities load under a feeder every 15 minutes using meter reading data that can be obtained from a power consumer every 15 minute or a month even without setting up any measuring equipment. After the data warehouse is constructed by interfacing the legacy system required for the load calculation, the relationship between the distribution system and the power consumer is established. Once the load pattern is forecasted by applying clustering and classification algorithm of temporal data mining techniques for the power customer who is not involved in Automatic Meter Reading(AMR), a single-line diagram per feeder is created, and power flow calculation is executed. The calculation result is analyzed using various temporal and spatial analysis methods such as Internet Geographic Information System(GIS), single-line diagram, and Online Analytical Processing (OLAP).
Study of Temporal Data Mining for Transformer Load Pattern Analysis
Shin, Jin-Ho ; Yi, Bong-Jae ; Kim, Young-Il ; Lee, Heon-Gyu ; Ryu, Keun-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1916~1921
This paper presents the temporal classification method based on data mining techniques for discovering knowledge from measured load patterns of distribution transformers. Since the power load patterns have time-varying characteristics and very different patterns according to the hour, time, day and week and so on, it gives rise to the uninformative results if only traditional data mining is used. Therefore, we propose a temporal classification rule for analyzing and forecasting transformer load patterns. The main tasks include the load pattern mining framework and the calendar-based expression using temporal association rule and 3-dimensional cube mining to discover load patterns in multiple time granularities.
An Operation Grouping and Its Maximum Allowable Conductor Temperature Considering Facility-conditions of Transmission Lines
Sohn, Hong-Kwan ; Kim, Byung-Geol ; Park, In-Pyo ; An, Sang-Hyun ; Jang, Tae-In ; Choi, Jang-Kee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1922~1928
The thermal rating of a conductor are maximum continuous current capacity and short time emergency current capacity. The overload operation for a faults have an effect on a conductor lifetime. Its time duration and overload level are limited to facility conditions of transmission lines. The short time emergency current capacity in KOREA observe the KEPCO's DESIGN RULE 1210, but its rules are not included to concept of an allowable short time duration. This papers are described to the calculation concept of short time emergency current capacity considering a time duration and an overload level. And we suggested a operation grouping and its maximum conductor temperature considering facility conditions - conductor lifetime, stability of connection points, conductor height above ground and clearance, in the operating and new T/L.
A Study on Calculation of Line- To-Ground Fault Current Split Factor to Earth in Overhead Transmission Lines
Choi, Jong-Kee ; Lee, Won-Kyo ; Choi, In-Hyuk ; Lee, Sang-Yun ; Hwang, Kab-Cheol ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1929~1932
In case of a line-to-ground fault at transmission lines, a portion of fault current will flow into the earth through the footings of the faulted tower causing electrical potential rise nearby the faulted tower footings. In this situation, any buried pipelines or structures nearby the faulted tower can be exposed to the electrical stress by earth potential rise. Although many research works has been conducted on this phenomena, there has been no clear answer of the required separation distance between tower footings and neary buried pipeline because of its dependancy on the soil electrical charactersics of the concerned area and the faulted system.
The International Standard Trends of MV Power Cable Installation Test and its Application on Korean Standard
Lee, Jae-Bong ; Jung, Yeon-Ha ; Song, Il-Keun ; Cho, Soung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1933~1937
XLPE insulated power cables are introduced in Korea in 1980s. The cable installation test has been carried out according to the Korean Technical Reference of Electrical Facilities. But recent research results shows DC Hipot test cannot detect the serious defects in XLPE insulated cables. VLF test is recommended as a installation test of XLPE insulated cables by CENELEC and IEEE standards in 1996 and 2001 respectively. We suggest to apply VLF test as an installation test for XLPE insulated MV cables in Korea.
A study on the Distribution Estimation of Residental Refrigerators using Bass Diffusion Model and Economic Analysis Corresponding to Enhancement of Energy Efficiency
Baek, Jung-Myoung ; Won, Jong-Ryul ; Lee, Byung-Ha ; Kim, Jung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1938~1945
Due to rapid economic growth, the usage of residential cooling electrical appliances such as air conditioners and refrigerators has increased dramatically for the last decades. In other to reduce its energy consumption, the authorities have applied energy efficiency standards for principal appliances, including refrigerator. This paper estimates the distribution of refrigerators using the Bass Diffusion Model and then performs economic analysis corresponding to enhancement of energy efficiency more correctly than existing methods.
Power Quality Analysis of Wind Farms interconnected in Jeju System during HVDC Overhaul
Chae, Woo-Kyu ; Yoon, Gi-Gab ; Cho, Seong-Soo ; Jung, Won-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1946~1953
Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected to three wind farms. It will be difficult to control of Jeju power system if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms have an effect on Jeju system during the HVDC overhaul last May. We concentrated on the power quality like frequency, voltage variation, voltage harmonics, current harmonics, flicker. We can found that the frequency of Jeju system is very unstable during overhaul, so the frequency of Jeju system can be variated easily by wind farm's rapid output power variation. There are some benefits and weak points in power quality between two wind farms because each wind farm is consist of different wind turbines.
A Method to Determine the Droop Constant of DGs Considering the Configuration and Active Power Control Mode
Ahn, Seon-Ju ; Park, Jin-Woo ; Chung, Il-Yop ; Moon, Seung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1954~1961
Microgrid usually consists of a cluster of distributed generators(DGs), energy storage systems and loads, and can operate in the grid-connected mode and the islanded mode. This paper presents detailed descriptions of two different options for controlling the active power of DGs in the microgrid. One is regulating the power injected by the unit to a desired amount(Unit output power control) and the other is to regulate the flow of active power in the feeder where the unit is installed to a constant(Feeder flow control). Frequency-droop characteristics are used to achieve good active power sharing when the microgrid operates in the islanded mode. The change in the frequency and the active power output of DGs are investigated according to the control mode and the configuration of DGs when the microgrid is disconnected from the main grid. From the analysis, this paper proposes a method to determine the droop constant of DGs operating in the feeder flow control mode. Simulation results using the PSCAD/EMTDC are presented to validate the approach, which shows good performance as opposed to the conventional one.
A Study on the Core Noise Reduction Techniques of Power Transformers
Kweon, Dong-Jin ; Koo, Kyo-Sun ; Cho, Ik-Choon ; Kim, Yoo-Hyun ; Kim, Yung-Sig ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1962~1969
According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint is increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an encloser to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation of the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. In this paper, we investigated core noise reduction techniques to develope a low noise transformer. The techniques to reduce core noise of the transformer are application of high permeability grain oriented silicon sheets, decrease of magnetic flux density of core, application of 6step-lap core stacking method, improvement of core binding method(binding addition, band fixing) and application of rubber damper in oder to reduce transmission of core vibration, etc.
Estimation of the Magnetic Field and the Critical Current of HTS BSCCO Pancake Windings
Koo, Myung-Hwan ; Kang, Myung-Hun ; Lee, Hee-Joon ; Cha, Guee-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1970~1975
Critical current of the superconducting machines is limited by the magnetic field. When the magnetic field is not uniform, it is difficult to estimate the magnetic field and the critical current. This paper proposed a method for the estimation of the magnetic field and the critical current of the HTS pancake windings which can be used to generate the high field magnet. A parameter which was needed to calculate the critical current of a BSCCO magnet with 10 pancake windings was obtained by the experiment. Test which was carried out by using single pancake winding and magnet consisting of 10 pancake windings shows the proposed method can be an effective method for the estimation of the critical current of pancake windings.
The Characteristic Analysis of SRM Dirven by Single-pulse Mode Considering the Voltage Ripple of DC Linke
Lee, Sung-Gu ; Jung, Dae-Sung ; Lee, Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1976~1980
This paper deals the characteristic analysis of Switched Reluctance Motor(SRM) driven by single-pulse mode considering dc link voltage ripple. Two dimensional time-stepped Finite Element Method(FEM) is used to analyze the characteristic of SRM driven by single-pulse mode with dc link voltage ripple. The analysis results is verified by experimental test.
Acoustic Resonance Reduction Technique in HID-lamps by the FM Driving Signal for the Inverter
Park, Chong-Yun ; Choe, Hyueon-Hui ; Lim, Ki-Seung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1981~1987
This paper proposed one of various acoustic resonance reduction technique for three kinds of ceramic lamps (CDM-150, HCI-150, CMH-150). To reduce the acoustic resonance in the HID lamps, the researched results showed that the frequency modulated signal with the triangle waveform is very effective in order to drive th LCC type half-bridge inverter for HID lamp. Experimental results proved that the acoustic resonance could be rejected, if the adequate switching frequency band is selected and the driving signal frequency is modulated with a triangle waveform.
Performance Simulation Results for Photovoltaic Module Modeling
So, Jung-Hun ; Yu, Byung-Gyu ; Hwang, Hye-Mi ; Yu, Gwon-Jong ; Choi, Ju-Yeop ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1988~1993
Photovoltaic (PV) modules operate over a large range of conditions but manufacturer's information is not sufficient to determine their overall performance. Designers need a reliable tool to predict energy production from a photovoltaic module under all conditions in order to make a sound decision. The modeling method of photovoltaic (PV) module are useful to perform detailed analysis of PV system performance for changing meteorological conditions, verify actual rated power of PV system sizing and determine the optimal design of PV system and components. This paper indicates a modeling approach of PV module performance in terms of meteorological conditions and identifies validity of PV modules modeling by comparing measured with simulated value.
Operation of Photovoltaic Generation System with Battery and Electrolyzer
Gang, Gi-Hyeok ; Kim, Yun-Seong ; Loc, Nguyen Khanh ; Won, Dong-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 1994~2000
The output power of photovoltaic(PV) generation system is strongly affected by weather conditions. To make up for the defect of solar energy, energy storages such as battery and electrolyzer are usually integrated with photovoltaic cell. This paper focuses on the way to store energy surplus with battery and electrolyzer and to provide energy with battery. Photovoltaic generation system is modeled with PV cell, DC/DC converter, DC/AC inverter, battery and electrolyzer. The operation algorithm to regulate PV output power with battery and electrolyzer is suggested. The simulation results show that battery and electrolyzer effectively cooperate with each other to compensate the fluctuation of PV generation system.
A Design of a Simulation Apparatus for the Control of the Personal Rapid Transit(PRT) Vehicles
Lee, Jun-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2001~2005
This paper presents a design of a simulation apparatus to evaluate an operational control algorithm for the PRT system. PRT systems require very short headways to increase the line capacity and a very reliable vehicle control algorithm for avoidance of the impact between vehicles. Therefore, it can be said that the development of an reliable operational control algorithm for the PRT systems is much more important than that of the hardware configurations. In this paper an apparatus is proposed which is composed of virtual vehicles, a central control system, a man-machine interface and monitoring device, making it possible for the designed operational control algorithm to be implemented and tested. For the test of the proposed apparatus a test operational control algorithm is designed and the experimental results show the effectiveness of the proposed simulation apparatus for test and evaluation of the PRT operational control algorithms.
Electrochemical Detection of Hydrogen Peroxide based on Viologen Monolayers
Choi, Won-Suk ; Lee, Dong-Yun ; Park, Sang-Hyun ; Park, Jae-Chul ; Kwon, Young-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2006~2010
In this paper, we fabricated a biosensor for detecting hydrogen peroxide and investigated the sensing property. We prepared a viologen and hemoglobin modified gold electrode using self-assembly and layer by layer method. The electrochemical property of the viologen derivative was characterized in 0.1 M
electrolyte solution by cyclic voltammetry. The modified electrode showed reversible electrochemical properties and high stability. From the results, the viologen can act as a charge transfer mediator for access to the electrode surface. The catalytic characteristics of the designed sensor proved that hemoglobin has been kept in its natural structure and can retain its biological activity. The designed biosensor showed a fast amperometric response, excellent linearity and low detection limit. In addition, it had high sensitivity, good reproducibility and stability.
Measurement on the permittivity and propagation velocity of used insulation oil at UHF Band using time domain reflectometry
Goo, Sun-Geun ; Ju, Hyoung-Jun ; Park, Ki-Jun ; Han, Ki-Seon ; Yoon, Jin-Yul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2011~2014
We measured the permittivity and electromagnetic wave propagation velocity of used insulation oil with wide frequency range including ultra-high frequency by time domain reflectometry. The permittivity or propagation velocity is essential for locating discharge faults of oil filled power transformer. We derived 2.21 as a permittivity and
as a velocity from the measurement of pulse travelling time along a coaxial line filled with used insulation oil or air. The permittivity measurement system we designed shows high measurement accuracy and the convenience for field use.
Effect of In Situ YAG on Properties of the Pressureless-Sintered SiC-
Electroconductive Ceramic Composites
Shin, Yong-Deok ; Ju, Jin-Young ; Ko, Tae-Hun ; Lee, Jung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2015~2022
The effect of content of
sintering additives on the densification behavior, mechanical and electrical properties of the pressureless-sintered
electroconductive ceramic composites was investigated. The
electroconductive ceramic composites were pressurless-sintered for 2 hours at 1,700[
] temperatures with an addition of
(6 : 4 mixture of
) as a sintering aid in the range of
[wt%]. Phase analysis of
composites by XRD revealed mostly of
and In Situ YAG(
). The relative density, flexural strength, Young's modulus and vicker's hardness showed the highest value of 89.02[%], 81.58[MPa], 31.44[GPa] and 1.34[GPa] for
composites added with 16[wt%]
additives at room temperature respectively. Abnormal grain growth takes place during phase transformation from
-SiC was correlated with In Situ YAG phase by reaction between
additive during sintering. The electrical resistivity showed the lowest value of
composite added with 16[wt%]
additives at 700[
]. The electrical resistivity of the
composite was all negative temperature coefficient resistance (NTCR) in the temperature ranges from room temperature to 700[
]. Compositional design and optimization of processing parameters are key factors for controlling and improving the properties of SiC-based electroconductive ceramic composites.
Effect of the Third Electrode of a Needle-Mesh Airgap on Ionic Wind Generation
Hwang, Deok-Hyun ; Moon, Jae-Duk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2023~2026
Cooling technologies using natural and forced convection are limited and operated in very low efficiency. The corona discharge is utilized as the driving mechanism for an ionic pump, which allows for air flow control and generation with low noise and no moving parts. These ideal characteristics of ionic pump give rise to variety applications. However, all of these applications would benefit from maximizing the flow velocities and efficiencies of the pumps. In this study a needle-mesh type ionic pump, with a ring type third electrode installed just near the needle point, has been investigated by focusing on elevating the ionic wind velocity and efficiency. As a result, the enhanced ionic wind velocity and increased power yield can be obtained with the proposed ionic pump with the third electrode.
Calculations on the Reduction Rate of Ground Level Magnetic Fields due to Varying Configurations of Overhead Transmission Line
Min, Suk-Won ; Kim, Eung-Sik ; Park, Jun-Hyeong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2027~2034
There are concerns on possible health effects from exposure to electromagnetic fields. One reflection of this concerns is the considerable controversy, delay, and cost increases involved in the construction of power lines and facilities. To cope with such challenges, in this paper we investigated magnetic fields reduction techniques such as general compaction, in' span compaction, cruciform, vertical, 3 way splits phase, and 4way splits phase. As results, we found general compaction and 4 way splits phase could reduce magnetic fields up to 90%, while cruciform, vertical, and 3 way splits phase gave lower reduction rates of 30% because these configurations were similar to a current type of low reactance arrangement. We also knew 1 spacer in span compaction was appropriate in Korea in view of effectiveness and economy.
The Development of System for Measuring Ion Generated from HVDC Overhead Transmission Line
Ju, Mun-No ; Yang, Kwang-Ho ; Lee, Dong-Il ; Shin, Koo-Yong ; Lim, Jae-Seop ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2035~2040
The electrical discharge of high voltage direct current(HVDC) overhead transmission line generate audible noise, radio noise, electric field, ion current and induced voltage on the ground. These items are major factors to design environmentally friendly configuration of DC transmission line. Therefore, HVDC transmission lines must be designed to keep all these corona effects within acceptable levels. Several techniques have been used to assess interference caused by ions on HVDC overhead transmission line. In this study, to assess the ion characteristic of DC line, the ion current density and induced voltage caused by ion flow were measured by plate electrodes manufactured from a metal flat board and charged bodies, respectively. The charged body has two types of cylinder and cylindrical plate. From the results of calibration experiments, the sensitivity of flat electrode and charged body can be obtained. At present, the developed system is used to investigate the ion generation characteristics of Kochang DC
A Study for the Equivalent Circuit and Slow-Wave Factor of Defected Ground Structure Transmission Line
Lim, Jong-Sik ; Koo, Ja-Kyung ; Han, Sang-Min ; Jeong, Yong-Chae ; Ahn, Dal ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2041~2046
A frequency-dependent slow-wave factor (SWF) and equivalent circuit model of transmission line with defected ground structures (DGS) is described. Once S-parameters of a DGS transmission line are given, the conventional frequency -independent equivalent circuit elements are extracted using 3dB cutoff and resonant frequencies (Fc and Fo) as the first step. Using the initial equivalent elements and simple transmission line theories, a frequency-dependent equivalent transmission line model is established through an analytical method, and finally the frequency dependent SWF is calculated. The proposed equivalent circuit model and SWF are frequency-dependent and more reliable because even small insertion loss within available passband is considered, while they have been independent of frequency.
Modeling of Propagation Interference and Channel Application Solution Suggestion In the UHF Band RFID Propagation Path
Moon, Young-Joo ; Yeo, Seon-Mi ; Jeon, Bu-Won ; Roh, Hyoung-Hwan ; Joung, Myoung-Sub ; Oh, Ha-Ryoung ; Seong, Yeong-Rak ; Park, Jun-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2047~2053
Auto-ID industries and their services have been improved since decades ago, and radio frequency identification (RFID) has been contributing in many applications. Product management can be the foremost example. In our industrial experiences, RFID in ultra high frequency (UHF) band provides much longer interrogation ranges than that of 13.56MHz; many more applications exist thereby. There should be several interesting and useful ideas on UHF RFID; however, those ideas can be limited due to the inevitable environmental circumstances that restrict the interrogation range in shorten value. This paper discusses the propagation interference among different types of readers (e.g, mobile RFID readers in stationary reader zone) in dense-reader environment. In most cases, UHF RFIDs in Korea will be dependent on the UHF mobile RFIDs. In this sense, the UHF mobile users accidently move into the stationary reader's interrogation zone. This is serious problem. In this paper, we analyze propagation loss and propose the effective channel allocation scheme that can contribute developing less-invasive UHF RFID networks. The simulation and practical measurement process using the commercial CAD tools and measurement equipments are presented.
Performance Enhancement of Tension Controller for the Yarn Manufacturing Process
Kwak, Young-Shin ; Lim, Hoon ; Lee, Jang-Myung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2054~2060
This paper aims at the performance enhancement of tension controller for the yarn manufacturing process. The tension controller is required to keep the tension constant while the yarn is manufactured by a draw and twist machine, which is essential and critical for good quality production of yarn, steel, paper, etc. This paper proposes a linear model of tension control plant to develop a precise tension control system, which is derived by the close observation of the conventional mathematical model of motor driving and tension control systems. It is shown by experiments that the proposed control system precisely maintains the tension constant within the error bound of 0.05% while the conventional PI controller has about 0.2% error. The control performance of the system has been compared to that of conventional PI control not only for constant speed control but also for transient speed control experiments.
The Study on Intelligent Cooling Load Forecast of Ice-storage System
Koh, Taek-Beom ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2061~2065
In the conventional operation of ice-storage system based on operator's experience and judgement, the failure in forecast of cooling load occurs frequently due to operator's misjudgement and unskilled operation. This study presents the method of constructing self-organizing fuzzy models which forecast tomorrow temperature, humidity and cooling load periodically for economic and efficient operation of ice-storage system. To check the effectiveness and feasibility of the suggested algorithm, the actual example for forecasting temperature, humidity and cooling load of ice- storage system in KEPCO training institute, Sokcho, is examined. The computer simulation results show that the accuracy of temperature, humidity, cooling load forecast of the suggested algorithm is higher than that of the conventional methods.
Delay-dependent Stability Criteria for Uncertain Stochastic Neural Networks with Interval Time-varying Delays
Kwon, Oh-Min ; Park, Ju-Hyun ; Lee, Sang-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2066~2073
In this paper, the problem of global asymptotic stability of uncertain stochastic neural networks with delay is considered. The delay is assumed to be time-varying and belong to a given interval. Based on the Lyapunov stability theory, new delay-dependent stability criteria for the system is derived in terms of LMI(linear matrix inequality). Three numerical examples are given to show the effectiveness of proposed method.
Development of a Matlab Toolbox for Guidance & Traction Control Designs of an Articulated Transportation Vehicle
Min, Kyung-Deuk ; Yun, Kyoung-Han ; Kim, Young Chol ; Byun, Yeun-Sub ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2074~2079
This paper presents a software toolbox with
developed for the various performance analysis of an automatic guidance system of the Bimodal Tram. The Bimodal Tram is a new kind of transportation vehicle which could be an all-wheel steered multiple-articulated vehicle. This vehicle has to be equipped with an automatic guidance, traction/braking, and docking system, In the stage of developing such a system, its validities and performances should be verified under various operation conditions. For the purpose of doing these things through simulation, this toolbox has been developed and demonstrated well by applying it to the KRRI model.
A Study on Improvement Method for Statistical Process and Quality of Electric Demand Load Profile
Ko, Jong-Min ; Yang, Il-Kwon ; Jung, Nam-Jun ; Jin, Sung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2080~2085
KEPCO's AMR (Automatic Meter Reading) is a system that performs the real-time inspection and management of the 15-minute load profile of electric power consumption through a wired and/or wireless network such as CDMA. It has been utilized widely for real-time collection and data analysis. So far, KEPCO has focused on establishing wireless networks using CDMA and collecting data in real time but failed to consider sufficiently performances that can improve the quality of the original data required in terms of data utilization as well as establish the summary information. In this paper, we are going to show the functions that improve data quality by recording the final renewal time of any erroneous data and maintaining such data lists to use them in the rebuilding of summary information. The goals are to reduce any load applied mainly on the DBMS (Database Management System) of AMR, to enable the real-time performance of establishment in the summary information, and to obtain high-quality inspection data. The performance evaluation result has revealed a 10-fold improvement compared to the traditional disk-based DBMS system when the summary information is established.
A Method to Detect Multiple Plane Areas by using the Iterative Randomized Hough Transform(IRHT) and the Plane Detection
Lim, Sung-Jo ; Kim, Dae-Gwang ; Kang, Dong-Joong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2086~2094
Finding a planar surface on 3D space is very important for efficient and safe operation of a mobile robot. In this paper, we propose a method using a plane detection cell (PDC) and iterative randomized Hough transform (IRHT) for finding the planar region from a 3D range image. First, the local planar region is detected by a PDC from the target area of the range image. Each plane is then segmented by analyzing the accumulated peaks from voting the local direction and position information of the local PDC in Hough space to reduce effect of noises and outliers and improve the efficiency of the HT. When segmenting each plane region, the IRHT repeatedly decreases the size of the planar region used for voting in the Hough parameter space in order to reduce the effect of noise and solve the local maxima problem in the parameter space. In general, range images have many planes of different normal directions. Hence, we first detected the largest plane region and then the remained region is again processed. Through this procedure, we can segment all planar regions of interest in the range image.
A performance improvement of neural network for predicting defect size of steam generator tube using early stopping
Jo, Nam-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2095~2101
In this paper, we consider a performance improvement of neural network for predicting defect size of steam generator tube using early stopping. Usually, neural network is trained until MSE becomes less than a prescribed error goal. The smaller the error goal, the greater the prediction performance for the trained data. However, as the error goal is decreased, an over fitting is likely to start during supervised training of a neural network, which usually deteriorates the generalization performance. We propose that, for the prediction of an axisymmetric defect size, early stopping can be used to avoid the over-fitting. Through various experiments on the axisymmetric defect samples, we found that the difference bet ween the prediction error of neural network based on early stopping and that of ideal neural network is reasonably small. This indicates that the error goal used for neural network training for the prediction of defect size can be efficiently selected by early stopping.
A Study on the Fault Current Discrimination Using Enhanced Fuzzy C-Means Clustering
Jeong, Jong-Won ; Lee, Joon-Tark ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2102~2107
This paper demonstrates a enhanced FCM to identify the causes of ground faults in power distribution systems. The discrimination scheme which can automatically recognize the fault causes is proposed using Fuzzy RBF networks. By using the actual fault data, it is shown that the proposed method provides satisfactory results for identifying the fault causes.
Optimization of FCM-based Radial Basis Function Neural Network Using Particle Swarm Optimization
Choi, Jeoung-Nae ; Kim, Hyun-Ki ; Oh, Sung-Kwun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2108~2116
The paper concerns Fuzzy C-Means clustering based Radial Basis Function neural networks (FCM-RBFNN) and the optimization of the network is carried out by means of Particle Swarm Optimization(PSO). FCM-RBFNN is the extended architecture of Radial Basis Function Neural Network(RBFNN). In the proposed network, the membership functions of the premise part of fuzzy rules do not assume any explicit functional forms such as Gaussian, ellipsoidal, triangular, etc., so its resulting fitness values directly rely on the computation of the relevant distance between data points by means of FCM. Also, as the consequent part of fuzzy rules extracted by the FCM - RBFNN model, the order of four types of polynomials can be considered such as constant, linear, quadratic and modified quadratic. Weighted Least Square Estimator(WLSE) are used to estimates the coefficients of polynomial. Since the performance of FCM-RBFNN is affected by some parameters of FCM-RBFNN such as a specific subset of input variables, fuzzification coefficient of FCM, the number of rules and the order of polynomials of consequent part of fuzzy rule, we need the structural as well as parametric optimization of the network. In this study, the PSO is exploited to carry out the structural as well as parametric optimization of FCM-RBFNN. Moreover The proposed model is demonstrated with the use of numerical example and gas furnace data set.
Design of Portal System Architecture for Large Consumers and Its Prototype Implementation
Yang, Il-Kwon ; Kim, Sun-Ic ; Song, Jae-Ju ; Oh, Do-Eun ; Lee, Sang-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2117~2123
This paper describes the portal system architecture of large consumers for ESP(Energy Service Provider) to provide customers with various value added services such as monitoring and controlling a wide variety of electric devices in consumer's premises for optimal energy management from both consumer side and ESP side, and the prototype implementation of 2 kinds of value added services. The architecture is composed of the device portal which gathers the information from electric devices and controls them and the consumer portal which can make ESP operate the optimal energy management with two-way communications. The demand side management and energy management functions was chosen and implemented for the prototype system as value added services. The prototype was designed to create, manage, and trace the events about services between ESP and customers.
Integrated Packet Scheduling for VoIP Service
Lee, Eun-Joung ; Park, Hyung-Kun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2124~2126
In the wireless communication systems, the demand of multimedia services is also increased. Unlike typical data packets, realtime service such as VoIP packets have delay bound and low loss rate requirement. In this paper we propose a new scheduling algorithm that be able to allocate resources to the different kinds of services such as VoIP and data packet. The proposed algorithm considers both time delay and channel condition toe determine the priority. Simulation results show that the proposed algorithm works more efficiently than the conventional algorithms.
SIP based Tunable BPF for UHF TV Tuner Applications
Lee, Tae-C. ; Park, Jae-Y. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2127~2130
In this paper, a tunable bandpass filter with mutual inductive coupling circuits is newly designed and demonstrated for UHF TV tuner ranged from Ch.14(473MHz) to Ch.69(803MHz) applications. Conventional HF tuning circuit with an electromagnetic bandpass filter has several problems such as large size, high volume and high cost, since the electromagnetic filter is comprised of several passive components and air core inductors to be assembled and controlled manually. To address these obstacles, peaking chip inductor was newly applied for constructing the mutual inductive coupling circuit. The proposed circuit was newly and optimally designed, since the chip inductor showed lower components Q-value than the air core inductor. A varactor diode has been also used to fabricate the proposed tunable bandpass filter for RF tuning circuit. The fabricated tunable filter exhibited low insertion loss of approximately -3dB, high return loss of below -10dB, and large tuning bandwidth of 330MHz.
Comparison of Postural Sway in the Elderly Males and Females during Quiet Standing and Squat-and-Stand Movement
Kim, Ji-Won ; Kim, Da-Hye ; Moon, Ki-Wook ; Eam, Gwang-Moon ; Nam, Jung-Sook ; Kim, Yo-Han ; Hong, Jeong-Hwa ; Park, Bung-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 11, 2008, Pages 2131~2137
In this paper, COP (center of pressure) during quiet standing and squat-and-stand movement was analyzed to compare the postural control of young and elderly subjects with special interest in the elderly females who were reported to have higher fall rate than the elderly males. Subjects include the young subjects (10 males:
, 10 females:
) and the elderly subjects (8 males:
, 8 females:
). Analysis parameters were the mean of the distance between the instantaneous COP and the average COP (COP distance) and the mean of the COP movement velocity (COP velocity) in both AP (anterio-posterior) and ML (media-lateral) directions. During quiet standing, the COP distance in ML direction of elderly females was significantly greater than that of elderly males and the COP velocity of elderly females in both ML and AP direction were significantly greater than those of all the other groups. During squat and stand movement, the COP distance of elderly females was not significantly different with that of the elderly males. However, the COP velocity of elderly females was significantly greater than that of all the other groups. The large lateral weight shift (COP distance) of elderly females during quiet standing may explain their greater fall rate. However, this does not apply to squat-and stand movement. In contrast, COP velocity results show that the elderly females' COP is rapidly trembling compared to that of elderly males during both quiet standing and squat and-stand movement. This results suggest that rapid trembling or postural sway may reflect the reduced postural control ability and the risk of falling.