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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 58, Issue 12 - Dec 2009
Volume 58, Issue 11 - Nov 2009
Volume 58, Issue 10 - Oct 2009
Volume 58, Issue 9 - Sep 2009
Volume 58, Issue 8 - Aug 2009
Volume 58, Issue 7 - Jul 2009
Volume 58, Issue 6 - Jun 2009
Volume 58, Issue 5 - May 2009
Volume 58, Issue 4 - Apr 2009
Volume 58, Issue 3 - Mar 2009
Volume 58, Issue 2 - Feb 2009
Volume 58, Issue 1 - Jan 2009
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Analysis of the Overvoltages during Energizing Transmission Lines using EMTP
Yeo, Sang-Min ; Kim, Chul-Hwan ; Lyu, Young-Sik ; Joo, Haeng-Ro ; Cho, Burm-Sup ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 873~878
When the transmission lines are initially energized for power system restoration, the power system suffers the various overvoltages that can be classified as steady-state, transient, and dynamic overvoltages. For the accurate analyses of these overvoltages, many researchers utilize different simulation tools such as Power System Simulator for Engineering(PSS/E). Although PSS/E provides good solutions in steady-state and dynamic overvoltages, it is not suitable for transient overvoltages. Therefore, transient overvoltages are simulated by using Electro-Magnetic Transients Program(EMTP) developed for the analysis of transients in the power system. Recently, EMTP can be also used to simulate dynamic behavior of the system. In order to analyze the transient overvoltages with steady-state and dynamic overvoltages, the authors adopt EMTP as the simulation tool for the analysis of overvoltages. This paper presents the simulation results for the analyses of various overvoltages, and the possibility of EMTP to be used for these types of analyses.
Method for Detection of Saturation of a Current Transformer
Nam, Soon-Ryul ; Choi, Joon-Ho ; Kang, Sang-Hee ; Min, Sang-Won ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 879~884
A Method for detection of saturation of a current transformer(CT) is proposed. The algorithm is initiated when the end point of a saturation period is detected. This detection is achieved by checking the time interval between the adjacent zero-crossing points of the second derivative of the secondary current. Once the end point of the saturation period is detected, the beginning point of the corresponding saturation period is determined by backward examination of the sum of the secondary current from the end point. The performance of the algorithm was evaluated for a-g faults on a 345 kV 100km overhead transmission line. The Electromagnetic Transient Program(EMTP) was used to generate fault current signals for different fault inception angles and different remanent fluxes. The performance evaluation shows that the proposed algorithm successfully detects the saturation period even in the presence of a remanent flux.
Transmission Line Fault Location Algorithm Using Estimated Local Source Impedance
Kwon, Young-Jin ; Kim, Su-Hwan ; Kang, Sang-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 885~890
A fault location algorithm using estimated local source impedance after a fault is proposed in this paper. The method uses after fault data only at the local end. It uses the negative sequence current distribution factor for more accurate estimation. The proposed algorithm can keep up with the variation of the local source impedance. Therefore, the proposed algorithm especially is valid for a transmission line interconnected to a wind farm that the equivalent source impedance changes continuously. The performance of the proposed algorithm was verified under various fault conditions using the Simpowersystem of MATLAB Simulink. The proposed algorithm is largely insensitive to the variation in fault distance and fault resistance. The test results show a very high accurate performance.
A Study on the Intelligent Load Management System Based on Queue with Diffusion Markov Process Model
Kim, Kyung-Dong ; Kim, Seok-Hyun ; Lee, Seung-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 891~897
This paper presents a novel load management technique that can lower the peak demand caused by package airconditioner loads in large apartment complex. An intelligent hierarchical load management system composed of a Central Intelligent Management System(CIMS) and multiple Local Intelligent Management Systems(LIMS) is proposed to implement the proposed technique. Once the required amount of the power reduction is set, CIMS issues tokens, which can be used by each LIMS as a right to turn on the airconditioner. CIMS creates and maintains a queue for fair and proper allocation of the tokens among the LIMS requesting tokens. By adjusting the number tokens and queue management policies, desired power reduction can be achieved smoothly. The Markov Birth and Death process and the Balance Equations utilizing the Diffusion Model are employed for evaluation of queue performances during transient periods until the static balances among the states are achieved. The proposed technique is tested using a summer load data of a large apartment complex and give promising results demonstrating the usability in load management while minimizing the customer inconveniences.
A Study on the Web-based Overall Information Management System Developement of the Overhead Distribution Facilities Using SIAS
Lee, Dong-Yeop ; Kim, Dong-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 898~904
The objective of the present study lies in constructing web-based GIS system providing broad range of information applicable for power/telecommunications distribution facilities through cable. Nowadays, Korea is renowned forits faste sttele communications network across the nation enjoyable for being a test-runbed by worldwide contents providers. It is not too much to say that the trend is caused by the fact that Korea utilizes the cobweb-like power transmission cables applicable for the nationwide telecommunications networking. In particular, the trend has been all the more encouraged by the governmental drive to expedite the telecommunication network by way of the established power transmission facilities deemed as publicutility. Nevertheless, few can deny that the overexcessive competition among telecommunication service providers increasingly gives rise to unauthorized, arbitrary facilitation of distribution devices, which becomes much burden in operating the normal power/telecommunications distribution facilities by a power-generating company. In this regard, the study, to cope with such problems, attempts to develop a web GIS-based information management system compatible with NDIS(New Distribution Information System), a distribution facility management system now under operation by KEPCO, making advantage of GE Energy's SIAS(Smallworld Internet Application) technology. The model provided by this study is expected to get closer into effective operation of distribution facilities along with better sharing of information among conventional telecommunications operators, while getting rid of infringed facilitation cases
An Analysis of Recloser Operation According to Recovery Characteristics of Superconducting Fault Current Limiter
Rhee, Sang-Bong ; Kim, Chul-Hwan ; Kim, Kyu-Ho ; Kim, Jae-Chul ; Hyun, Ok-Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 905~910
For proper application and operation of a SFCL(Superconducting Fault Current Limiter) in distribution systems, the prior investigation of fundamental characteristics and its effects analysis to the systems are very important. A point of view in coordination with recloser in distribution systems, characteristic about quenching and recovering of SFCL should be studied. Especially, its detailed study of recovery characteristic is particularly important to avoid conflict between the SFCL and the recloser. In this paper, the resistive type SFCL and recloser, which used in distribution system, were implemented using EMTP/ATPDraw and MODELS language. To analyze the recovery characteristics of SFCL according to recloser operation in distribution systems, case studies have been simulated and investigated.
Regional Grouping of Transmission System Using the Sequential Clustering Technique
Kim, Hyun-Houng ; Lee, Woo-Nam ; Park, Jong-Bae ; Shin, Joong-Rin ; Kim, Jin-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 911~917
This paper introduces a sequential clustering technique as a tool for an effective grouping of transmission systems. The interconnected network system retains information about the location of each line. With this information, this paper aims to carry out initial clustering through the transmission usage rate, compare the similarity measures of regional information with the similarity measures of location price, and introduce the techniques of the clustering method. This transmission usage rate uses power flow based on congestion costs and similarity measurements using the FCM(Fuzzy C-Mean) algorithm. This paper also aims to prove the propriety of the proposed clustering method by comparing it with existing clustering methods that use the similarity measurement system. The proposed algorithm is demonstrated through the IEEE 39-bus RTS and Korea power system.
A Study on the Generation Expansion Planning System Under the Cost Based Pool
Han, Seok-Man ; Kim, Bal-Ho H. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 918~922
The power expansion planning is large and capital intensive capacity planning. In the past, the expansion planning was established with the proper supply reliability in order to minimize social cost. However, the planning cannot use cost minimizing objective function in the power markets with many market participants. This paper proposed the power expansion planning process in the power markets. This system is composed of Regulator and GENCO's model. Regulator model used multi-criteria decision making rule. GENCO model is very complex problem. Thus, this system transacted the part by several scenario assuming GENCO model.
A Comparative Analysis of Test Methods of Measuring d- and q-Axes Inductances for Interior Permanent Magnet Synchronous Motor
Kim, Seung-Joo ; Kim, Cherl-Jin ; Lee, Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 923~928
The performance analysis and robust control of the interior permanent magnet synchronous motor(IPMSM) greatly depend on accurate value of its parameters. To achieve the high performance of torque control, it is necessary to consider exact inductance values because the inductances are nonlinear parameters of operating the IPMSM. Therefore many different methods have been performed for analysis of the methodology for the exact measurement of synchronous inductances. None of them is considered standard, and accuracy levels of all these methods are also not consistent. Among these experimental methods, the DC current decay test and the vector current control test are ideal for a laboratory environment. In this paper, these two test methods are compared by applying inductances to the IPMSM. The paper analyzes the measured inductances of the two methods and their differences with inductances obtained from the finite element method(FEM).
Analysis on Air-Gap Magnetic Flux of Synchronous Generator According to Short-Circuit Types in Winding
Bae, Duck-Kweon ; Kim, Dong-Hun ; Park, Jung-Shin ; Lee, Dong-Young ; Lee, Sung-Ill ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 929~935
As modem industrialized society progresses, the demand for electric power is increasing rapidly. The electric power system is getting amazingly bigger and complicated, which can easily induce serious troubles from the potential of large fault problems and/or system failure. The monitoring and diagnosis of the electric machine for the fault detection and protection has been important part in the electric power system. Most faults in the generator appear in the winding. This paper presents the air-gap magnetic flux characteristic of a small-scale 2-pole synchronous generator according to the faults in the field winding to protect the generator from the fault. The magnetic flux patterns in air-gap of a generator under various fault conditions as well as a normal state are simulated by using finite element method. These results are successfully applied to the detection and diagnosis of the short-circuit condition in rotor windings of a high capacitor generator.
Improvement of PLL Method for Voltage Control of Dynamic Voltage Restorer
Kim, Byong-Seob ; Choi, Jong-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 936~943
Dynamic voltage restorer(DVR) is now more preferable enhancement than other power quality enhancement in industry to reduce the impact of voltage faults, especially voltage sags to sensitive loads. The main controllers for DVR consists of PLL(phase locked loop), compensation voltage calculator and voltage compensator. PLL detects the voltage faults and phase. Compensation voltage calculator calculates the reference voltage from the source voltage and phase. With calculated compensation voltage from PLL, voltage compensator restores the source voltage. If PLL detect ideal phase, compensation voltage calculator calculates ideal compensation voltage. Therefore, PLL for DVR is very important. This paper proposes the new method of PLL in DVR. First, the power circuit of DVR system is analyzed in order to compensate the voltage sags. Based on the analysis, new PLL for improving transient response of DVR is proposed. The proposed method uses band rejection filter(BRF) at q-axis in synchronous flame. In order to calculate compensation voltage in commercial instruments, the PQR theory is used. Proposed PLL method is demonstrated through simulation using Matlab-Simulink and experiment, and by checking load voltage, confirms operation of the DVR
A Simplified Power Controller in Electronic Ballast of HID Lamp
Lee, Seung-Hee ; Kim, Tae-Won ; Park, Tae-Jun ; Lee, Chi-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 944~949
A simplified power control technique for electronic ballasts of HID lamps is proposed. This power calculator and controller consist of regular operational amplifiers with some passive elements and form simple add operation circuit. From a mathematical model of designed ballast with proposed power controller, the control performance and stability are analyzed by using Matlab and the results show that the stable starting characteristics and steady state characteristics of HID lamp are appropriately guaranteed. The experimental results of the prototype ballast coincide with the simulation results.
A Cost Effective DC Link Variable Inverter Using 2-Switch Buck-Boost Converter
Kang, Hyun-Soo ; Kim, Jun-Hyung ; Lee, Byoung-Kuk ; Hur, Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 950~959
In this paper, a dc link voltage variable inverter system is proposed, which consists of a two-switch buck-boost converter and a four-switch inverter. In addition, as the current and torque ripples are generated by a voltage difference between back EMF and dc link voltage, these ripples could be reduced according to the controlled dc-link voltage according to the motor speed. The validity of the proposed inverter is verified by informative simulation and experimental results.
A Risk Assessment Approach to Safety Management of Electric Railway Facilities
Jang, Yoon-Suk ; Choi, Kyu-Hyoung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 960~967
Power supply system of electric railway has a diversity of safety problems since it should supply high electric power to the trains moving high speed with a lot of passengers on board. This paper provides a risk assessment approach to safety management of the electric railway facilities. Construction of database from field accident information, risk assessment and management of the risk are carried out systematically to ensure the safety. The risk assessment includes hazard identification, cause analysis by FTA(Fault Tree Analysis), consequence analysis by EVA(Event Tree Analysis), and loss analysis. In terms of the severity and the probability of the accidents deduced by these analyses, the risk of the accidents is assessed by using a risk matrix designed for electric railway facilities. Based on the risk assessment, possible risk mitigation options are identified and evaluated by analyzing their impact on the risk reduction and their cost benefit ratio. The long-term safety of the electric railway facilities can be ensured by renewal of the risk assessment and the risk mitigation option analysis with continuous accident database update. The proposed approach is applied to the electric railway facilities of Korean railway based on the accident data from 2002 to 2008.
A Study on the Control Characteristics for Reduction of Particulate Material by HC Injection
Kim, Byeong-Woo ; Hur, Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 968~975
The goals of this research are to understand the regeneration characteristics in diesel particulate filter using the HC injection. This research emphasized on the development of Continuously Regenerating DOC/DPF and HC technology which was the best particulate matters removing technology of current existing technology. This experimental study has been conducted with equipped a Continuously Regenerating DOC/DPF and HC injection on displacement 2.0, 3.3
diesel engine and compared in terms of particulate material and emission. In this study, we could constructed 3 kinds of database according to quantity of temperature to decide the HC injection quantity and develop DOC/DPF ECU algorithm.
Optimal Design of Thin Type Ultrasonic Motor and Development of Driver
Jeong, Seong-Su ; Jun, Ho-Ik ; Park, Tae-Gone ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 976~981
This paper proposed optimal design and microcontroller driver for driving the thin-type ultrasonic motor. To find the optimal size of the stator, motions of the motor were simulated using ATILA by changing length, width and thickness of the ceramics. Two sinusoidal waves which have 90 degree phase difference were needed for driving the thin-type motor. The thin-type ultrasonic motor driver was composed of microcontroller(Atmega128), push-pull inverter, encoder and AD-converter. Microcontroller generates four square waves which have variable frequency and 25[%] duty ratio in
[kHz]. The output signals of microcontroller were converted to sine wave and cosine wave by push-pull inverter and were applied to the thin-type ultrasonic motor. The encoder and AD-converter were used for maintaining speed of the thin-type ultrasonic motor. The AD-converter controlled DC voltage of inverter in accordance with output signal of encoder. Using the driver, characteristics of the motor as speed and torque were measured.
Improvement of Luminance and Luminous Efficacy in Mid-gap AC Plasma Display Panels
Choi, Nak-Won ; Min, Chung-Sik ; Jeong, Dong-Cheol ; Seo, Jeong-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 982~988
In a surface type ac PDP having
gap between the surface electrodes, the luminous efficacy has a reciprocal dependence on the sustaining frequency. The discharge current flowing to the address electrodes are measured to investigate the phenomena and spectral intensity from visible light to infra red is measured to verify phosphor saturation with the frequency. Experiments show the discharge between the address and surface electrodes deteriorates the efficacy in high sustaining frequencies. Pulse width modulation is introduced to improve the efficacy. In optimum conditions, we obtained 1.99lm/w and 1.79lm/w at 200kHz and 250kHz, respectively.
Study on Insulation Prediction of Triple Junction in
Cho, Yong-Sung ; Chong, Jin-Kyo ; Lee, Woo-Young ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 989~993
Triple junction which consists of three media(electrode, insulator, and gas) should be considered in designing of high voltage equipments due to the electric field enhancement. In this paper, positive lightning impulse breakdown voltage is predicted based on the streamer theory for simplified insulator models and 72.5kV spacer with varying the triple junction geometry and gas pressure, and the results are compared to the experimental results. The electric field coefficient concept is also applied in order to evaluate the partial discharge inception voltage and the surface flashover voltage from the streamer inception voltage. The application of this method using the constant electric field coefficient of 1.3 and 0.66 is possible for evaluating the triple-junction insulation of the simplified insulator and the 72.5kV spacer respectively. The error rate is under 10%.
Effect of Discharge Electrode Shape of a Barrier Discharge Type Gas Pump on Ionic Wind Generation
Hwang, Deok-Hyun ; Moon, Jae-Duk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 994~998
Existing cooling technologies no longer provide adequate heat dissipation due to excessive heat generation caused by the growing component density on electronic devices. An ionic gas pump can be used for the thermal management of micro-electronic devices, since the size of pump can be reduced to a micrometer scale. In addition, the gas pump allows for gas flow control and generation without moving parts. This ideal property of gas pump gives rise to a variety of applications. However, all these applications require maximizing the wind velocity of gas pump. In this study a barrier discharge type gas pump, with a needle-shaped corona electrode instead of a plate-shaped corona electrode, has been investigated by focusing on the corona electrode shape on the wind velocity and wind generation yield. As a result, the enhanced wind velocity and wind generation yield of 1.76 and 3.37 times were obtained with the needle-shaped corona electrode as compared with the plate-shaped corona electrode of the proposed barrier discharge type gas pump.
Linearization of CMOS Drive Amplifier with IMD Canceller
Kim, Do-Gyun ; Hong, Nam-Pyo ; Moon, Yon-Tae ; Choi, Young-Wan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 999~1003
We have designed and fabricated a linear drive amplifier with a novel intermodulation distortion(IMD) canceller using
CMOS process. The drive amplifier with IMD canceller is composed of a cascode main amplifier and an additional common-source IMD canceller. Since the IMD canceller generates IM3(
-order imtermodulation) signal with
phase difference against the IM3 of the cascode main amplifier, the IM3 power is drastically eliminated. As of the measurement results,
, and power-add efficiency are 5.5 dBm, 15.5 dBm, and 21%, respectively. Those are 5 dB, 6 dB, and 13.5% enhanced values compared to a conventional cascode drive amplifier. The IMD3 of the drive amplifier with IMD canceller is enhanced more than 10 dB compared to that of the conventional cascode drive amplifier for input power ranges from -22 to -14 dBm.
The Improvement of the Ionization on Micro Mass Spectrometer using Carbon Nanotube Emitter
Song, S.H. ; Han, Kyu-Sung ; Hong, Nguyen Tuan ; Lee, S.I. ; Yang, Sang-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1004~1009
Recently, mass spectrometers are widely used for in-situ chemical analysis. It has rapid response and high sensitivity. In this paper, we present the fabrication and test of a cold cathode emitter for micro mass spectrometer using CNTs(Carbon nano tubes). The CNTs have good mechanical, electrical and chemical characteristics. So they have a long life time and strong robustness. The micro mass spectrometer is composed of the glass substrate and the silicon substrate. The glass substrate is constructed by electrodes for TOF(Time-of-flight) which analyze an ion with mass to charge ratio as ion separator. The silicon substrate is highly doped wafer which is patterned for gate electrode and then 100 11m dry etching to grow the CNTs as the electron emitter. The CNTs are grown by HFCVD(Hot filament chemical vapor deposition) with sputtering the catalyst. We successfully attained to grow the CNTs and to test the characteristics.
Gait State Classification by HMMS for Pedestrian Inertial Navigation System
Park, Sang-Kyeong ; Suh, Young-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1010~1018
An inertial navigation system for pedestrian position tracking is proposed, where the position is computed using inertial sensors mounted on shoes. Inertial navigation system(INS) errors increase with time due to inertial sensor errors, and therefore it needs to reset errors frequently. During normal walking, there is an almost periodic zero velocity instance when a foot touches the floor. Using this fact, estimation errors are reduced and this method is called the zero velocity updating algorithm. When implementing this zero velocity updating algorithm, it is important to know when is the zero velocity interval. The gait states are modeled as a Markov process and each state is estimated using the hidden Markov model smoother. With this gait estimation, the zero or nearly zero velocity interval is more accurately estimated, which helps to reduce the position estimation error.
Implementation of Particle Swarm Optimization Method Using CUDA
Kim, Jo-Hwan ; Kim, Eun-Su ; Kim, Jong-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1019~1024
In this paper, particle swarm optimization(PSO) is newly implemented by CUDA(Compute Unified Device Architecture) and is applied to function optimization with several benchmark functions. CUDA is not CPU but GPU(Graphic Processing Unit) that resolves complex computing problems using parallel processing capacities. In addition, CUDA helps one to develop GPU softwares conveniently. Compared with the optimization result of PSO executed on a general CPU, CUDA saves about 38% of PSO running time as average, which implies that CUDA is a promising frame for real-time optimization and control.
Slab Region Localization for Text Extraction using SIFT Features
Choi, Jong-Hyun ; Choi, Sung-Hoo ; Yun, Jong-Pil ; Koo, Keun-Hwi ; Kim, Sang-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1025~1034
In steel making production line, steel slabs are given a unique identification number. This identification number, Slab management number(SMN), gives information about the use of the slab. Identification of SMN has been done by humans for several years, but this is expensive and not accurate and it has been a heavy burden on the workers. Consequently, to improve efficiency, automatic recognition system is desirable. Generally, a recognition system consists of text localization, text extraction, character segmentation, and character recognition. For exact SMN identification, all the stage of the recognition system must be successful. In particular, the text localization is great important stage and difficult to process. However, because of many text-like patterns in a complex background and high fuzziness between the slab and background, directly extracting text region is difficult to process. If the slab region including SMN can be detected precisely, text localization algorithm will be able to be developed on the more simple method and the processing time of the overall recognition system will be reduced. This paper describes about the slab region localization using SIFT(Scale Invariant Feature Transform) features in the image. First, SIFT algorithm is applied the captured background and slab image, then features of two images are matched by Nearest Neighbor(NN) algorithm. However, correct matching rate can be low when two images are matched. Thus, to remove incorrect match between the features of two images, geometric locations of the matched two feature points are used. Finally, search rectangle method is performed in correct matching features, and then the top boundary and side boundaries of the slab region are determined. For this processes, we can reduce search region for extraction of SMN from the slab image. Most cases, to extract text region, search region is heuristically fixed . However, the proposed algorithm is more analytic than other algorithms, because the search region is not fixed and the slab region is searched in the whole image. Experimental results show that the proposed algorithm has a good performance.
New Encoder/Decoder with Wavelength/Time 2-D Codes for Optical CDMA Network
Hwang, Hu-Mor ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1035~1040
We propose a new encoder/decoders based on an tune able wavelength converter(TWC) and an arrayed waveguide grating(AWG) router for large capacity optical CDMA networks. The proposed encoder/decoder treats codewords of wavelength/time 2-D code simultaneously using the dynamic code allocation property of the TWC and the cyclic property of the AWG router, and multiple subscribers can share the encoder/decoder in networks. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using two wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC) and the generalized multi-wavelength Reed-Solomon code(GMWRSC). Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.
Digital Watermarking Scheme based on SVD and Triplet
Park, Byung-Su ; Chu, Hyung-Suk ; An, Chong-Koo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1041~1046
In this paper, we proposed a robust watermark scheme for image based on SVD(Singular Value Transform) and Triplet. First, the original image is decomposed by using 3-level DWT, and then used the singular values changed for embedding and extracting of the watermark sequence in LL3 band. Since the matrix of singular values is not easily altered with various signal processing noises, the embedded watermark sequence has the ability to withstand various signal processing noise attacks. Nevertheless, this method does not guarantee geometric transformation(such as rotation, cropping, etc.) because the geometric transformation changes the matrix size. In this case, the watermark sequence cannot be extracted. To compensate for the above weaknesses, a method which uses the triplet for embedding a barcode image watermark in the middle of frequency band is proposed. In order to generate the barcode image watermark, the pattern of the watermark sequence embedded in a LL3 band is used. According to this method, the watermark information can be extracted from attacked images.
A Power-line Frequency Monitoring Intelligent Electronic Device(IED) Platform
Jeon, Hyeon-Jin ; Yi, Don-Jin ; Jeon, Jun-Gil ; Chang, Tae-Gyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1047~1049
This paper presents an intelligent electronic device(IED) platform which is based on a new frequency estimation algorithm. The IED platform features not only the accurate estimation of frequency but also the fast network-based transmisstion of fault data and waveforms. The simulation results show that the proposed frequency estimation algorithm improves convergence speed, and has lower frequency estimation error compared with those of conventional algorithms. The network-based IED is designed to ensure transmission latency being less than 1.0% of sampling interval.
A Study on the Measurement of Heart Rate Variability using the Modified Laplacian Electrodes
Lee, Chung-Keun ; Shin, Hang-Sik ; Kim, Hong-Rae ; Lee, Jeong-Whan ; Kim, Yong-Jun ; Lee, Myoung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 5, 2009, Pages 1050~1056
Heart Rate Variability(HRV) is a parameter that represents monitoring variability of time intervals between R-peak in electrocardiography. HRV serves to various applications, such as indices of autonomic functions, prediction of cardiac sudden death, assessment of stress and emotional, etc. However, as measuring R-peak in ECG needs at least 3-electrodes, and it is inconvenient for end users. In this paper, we suggested the modified laplacian electrodes for measuring HRV at one-point, which are producted by MEMS fabrication and have the two circular electrodes on the pad. For optimal position and direction, we performed an experiment that compared with pearson correlation coefficient and the amplitude of signals, between standard lead II and proposed electrodes. We analyzed the HRV parameters, such as standard deviation of the NN interval(SDNN), high frequency(HF), low frequency(LF), LF/HF ratio. The result showed that the average correlation coefficient and amplitude are 0.967 and 0.685 mVpp at the position 2. The coeffiecient correlation between the standard HRV and proposed electrode-HRV is 0.999