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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 56, Issue 12 - Dec 2007
Volume 56, Issue 11 - Nov 2007
Volume 56, Issue 10 - Oct 2007
Volume 56, Issue 9 - Sep 2007
Volume 56, Issue 8 - Aug 2007
Volume 56, Issue 7 - Jul 2007
Volume 56, Issue 6 - Jun 2007
Volume 56, Issue 5 - May 2007
Volume 56, Issue 4 - Apr 2007
Volume 56, Issue 3 - Mar 2007
Volume 56, Issue 2 - Feb 2007
Volume 56, Issue 1 - Jan 2007
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Ground Fault Current Variation of 22.9kV Multi Neutral Grounded Distribution System with CD Type Superconducting Cable
Lee, Jong-Bae ; Hwang, Si-Dole ; Sohn, Song-Ho ; Lee, Geun-Joon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 993~999
This paper discusses the effects of CD type superconducting cable operation in 22.9kV multi neutral grounded distribution system during L-G fault and counterplans to power system protection. In case of using the 3-phase CD-type superconducting cable, the inductance of superconducting cable system would be decreased due to the current of shield part of superconducting cable, which is opposite direction and nearly equal value with respect to main superconductor. However, when the shield circuit system is operated in shorted state, shield current decreases faulted ground current and give effects to power system protection scheme. This study examines the phenomena of single line to ground fault case in above mentioned system using the EMTDC program and discusses the right operation method of superconducting shield.
Power System Equilibrium Optimization (EOPT) with a Nonlinear Interior Point Method
Song, Hwa-Chang ; Dosano, Rodel D. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1000~1006
This paper presents a methodology to calculate an optimal solution of equilibrium to differential algebraic equations for power systems. It employs a nonlinear interior point method to solve the optimization formulation which includes dynamic equations representing the two-axis synchronous generator model with AVR and speed governing controls, algebraic equations, and steady-state nonlinear loads. This paper also adopts two algorithms for the improvement of solution convergence. In power system analysis and control, equilibrium optimization (EOPT) is applicable for diverse purposes that need the consideration of dynamic model characteristics at a steady-state condition.
Fault Diagnosis of Power Transformer by FCM and Euclidean Based Distance Measure
Lee, Dae-Jong ; Lee, Jong-Pil ; Ji, Pyeong-Shik ; Lim, Jae-Yoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1007~1016
In power system, substation facilities have become too complex and larger according to an extended power system. Also, customers require the high quality of electrical power system. However, some facilities become old and often break down unexpectedly. The unexpected failure may cause a break in power system and loss of profits. Therefore it is important to prevent abrupt faults by monitoring the condition of power systems. Among the various power facilities, power transformers play an important role in the transmission and distribution systems. In this research, we develop intelligent diagnosis technique for predicting faults of power transformer by FCM(Fuzzy c-means) and Euclidean based distance measure. The proposed technique make it possible to measures the possibility and degree of aging as well as the faults occurred in transformer. To demonstrate the validity of proposed method, various experiments are performed and their results are presented.
An Analysis on Possibility and Effect of Market Power under the 3rd Long Term Power Plan
Lee, Jae-Gul ; Park, Min-Hyuk ; Ahn, Nam-Sung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1017~1022
In this paper, we try to analyze the likelihood of exercising the power of market dominance by certain generators in future power industry of Korea. Firstly, we estimated installed generation capacity and sales volume of electricity in Korea, based on 'The 3rd Long Term Power Plan' which was announced in December 2006. Secondly, we calculated HHI, an index showing the degree of concentration of an industry, and RSI, an index showing how adequate the supply of goods or services of an industry is, using Fast-Forward. Thirdly, assuming a major generator employs the strategy of withholding a part of its available capacity at a peak time, we simulated hypothetical movement of SMP over a certain period of time, which is compared with that obtained without assuming such strategy to generate Lerner Index. an index showing the degree of market power of a monopoly. Regulators, home and abroad, have not given much interest in analyzing the effect of market dominance that is likely to be exercised by certain players in the future. That said, this paper provides insight into developing methodologies of analyzing and mitigating such effect by proposing the above indices to gauge it. In addition, this paper also shows the potential impact of employing capacity withholding strategy on the financial account of a dominant generator.
An Improved Particle Swarm Optimization Adopting Chaotic Sequences for Nonconvex Economic Dispatch Problems
Jeong, Yun-Won ; Park, Jong-Bae ; Cho, Ki-Seon ; Kim, Hyeong-Jung ; Shin, Joong-Rin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1023~1030
This paper presents a new and efficient approach for solving the economic dispatch (ED) problems with nonconvex cost functions using particle swarm optimization (PSO). Although the PSO is easy to implement and has been empirically shown to perform well on many optimization problems, it may easily get trapped in a local optimum when solving problems with multiple local optima and heavily constrained. This paper proposes an improved PSO, which combines the conventional PSO with chaotic sequences (CPSO). The chaotic sequences combined with the linearly decreasing inertia weights in PSO are devised to improve the global searching capability and escaping from local minimum. To verify the feasibility of the proposed method, numerical studies have been performed for two different nonconvex ED test systems and its results are compared with those of previous works. The proposed CPSO algorithm outperforms other state-of-the-art algorithms in solving ED problems, which consider valve-point and multi-fuels with valve-point effects.
A Study on the Transmission Tower Foundation Design and Construction Method - A Focus of Cylindrical Foundation -
Jang, Suk-Han ; Kim, Hee-Kwang ; Lee, Kang-Hyeon ; Han, Kyung-Soo ; Ham, Bang-Wook ; Chung, Ki-Sun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1031~1034
Electric transmission lines pass through a variety of area. Foundation supporting the conductors and tower are selected properly in accordance with external load, for example dead load, wind load, snow load, construction load etc, and topography and geology condition. Typical types of foundation are as follows: pad foundation for small load and hard soil or rock in mountainous area, pile foundation for medium or large load and soft soil in plain field area. This paper introduced cylindrical foundation design & construction for large load and mountainous area. This foundation failure mode against pulling-out show splitting failure by tensile force toward circumferential direction.
Development of a 1.8T HTS Insert Coil for High Field Magnet
Bae, Joon-Han ; Seong, Ki-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1035~1038
We designed and manufactured a 1.8T high temperature superconducting(HTS) insert coil for a NMR magnet operated at 4.2 K. Suitable HTS superconductor and HTS coil were carefully designed and developed. We have selected multi-filamentary Bi2223 conductor fabricated by American Superconductor Corporation(AMSC). The selected conductor consists of Bi2223 filaments of 55, silver stabilizer and stainless steel reinforcement tapes. Therefore, it shows good hoop strength as well as compression tolerance. The conductor has a tape cross-section of 0.31mm x 4.8mm. the Bi2223 conductor shows large anisotropy of critical current. The critical current of conductor in magnetic field parallel to the flat surface are much higher than that in magnetic field perpendicular. The HTS coil has an inner diameter of 78 mm, an outer diameter of 127 mm and a coil length of 600 mm. In this paper, the detailed design, fabrication and test results on the HTS insert coil are presented.
Characteristics Analysis and Comparison of Careless and Slotless BLDC Motor used in Digital Lightening Processor Motor with Air-Dynamic Bearing
Yang, Iee-Woo ; Kim, Young-Seok ; Kim, Sang-Uk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1039~1046
This paper presents the analysis for power consumption, mechanical vibration and acoustic noise characteristics of the Coreless and Slotless Brushless DC motor in Digital Lightening Processor(DLP) Motor with the Air-Dynamic Bearing. The Coreless BLDC motor has not the stator yoke as well as the stator slot to remove the unbalance force by the interaction between the stator yoke and Air-Dynamic Bearing clearance. The assembling tolerance and the processing error make the air-gap difference between the magnet and the stator yoke .which occurs the unbalanced electro-magnetic force in the Slotless BLDC motor. It imposes the air-dynamic bearing on the disturbance force and makes the Air-Dynamic Bearing vibrated and noised. Also, The attractive force between the magnet and the silicon steel stator yoke increases the power consumption. In this paper, the power consumption, mechanical vibration and acoustic noise of the Coreless BLDC motor and the Slotless BLDC motor with the silicon steel stator yoke are simulated, analyzed, and tested using the manufactured proto-type motors with Air-Dynamic bearing. The simulated and tested results present that the Coreless BLDC motor without the silicon steel stator yoke has the lower mechanical vibration and noise ,and lower power consumption than the Slotless BLDC motor with the silicon steel stator yoke in Digital Lightening Processor Motor with Air-Dynamic Bearing.
A High Efficiency Direct Instantaneous Torque Control of SRM based on the Nonlinear Model
An, Jin-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1047~1054
This paper presents a high efficiency direct instantaneous torque control (DITC) of Switched Reluctance Motor(SRM) based on the nonlinear model. The DITC method can reduce the high inherent torque ripple of SRM drive system, but drive efficiency is somewhat low due to the high current and switching loss during commutations. In order to reduce a torque ripple, a fast torque reference trajectory is selected at every instantaneous rotor position. Based on the nonlinear model of SRM, the developing torque by one phase is fixed and the other phase is regulated for minimum switchings of phase switch and variation of torque. The switching during commutation can be reduced and fast commutation can be obtained in the proposed method. As a result, drive efficiency could be improved as well as torque ripple reduction. The validity of proposed method is verified by computer simulations and comparative experiments.
Optimal Design of a Transformer Core Using DEAS
Kim, Tae-Gyu ; Kim, Jong-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1055~1063
This paper introduces an optimal design technique for a 250-watt isolation transformer using an optimization method, dynamic encoding algorithm for searches (DEAS). Although the optimal design technique for transformers dates back to 1970s and various optimization methods have been developed so far, literature concerning global optimization for transformer core design is rarely found against its importance. In this paper, core configuration of the isolation transformer whose performance is computed by complex mathematical steps is optimized with DEAS. The optimization result confirms that DEAS can be successfully employed to transformer core design for various performance specifications only by adjusting weight factors in cost function.
Gird-interactive Current Controlled Voltage Source Inverter System with UPS
Ko, Sung-Hun ; Lim, Sung-Hun ; Lee, Su-Won ; Lee, Seong-Ryong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1064~1070
This paper presents a grid-interactive current controlled voltage source inverter (CCVSI) with uniterruptible power supply (UPS), which uses an inner current control loop (polarized ramp time (PRT)) and outer feedback control loops to improve grid power quality and UPS. To reduce the complexity, cost and number of power conversions, which results in higher efficiency, a single stage CCVSI is used. The operation of this system could be divided into the power quality control (PQC) state mode and the UPS state mode. In PQC mode, the system operated to compensate the reactive power demand by nonlinear load or variation in load. In UPS mode. the system is controlled to provide a sinusoidal voltage at the rated value for the load when the gird fail. To verify the proposed system, a comprehensive evaluation with theoretical analysis, simulation and experimental results for 1KVA load capacity is presented.
A New Simplified Vector Control For A High Performance Common-Arm IHCML Inverter
Song, Sung-Geun ; Park, Sung-Jun ; Nam, Hae-Kon ; Kim, Kwang-Heon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1071~1079
In this paper, a novel space vector control method for isolated multi-level inverter using 3-phase low frequency transformers is proposed. This method is based on the simplification of the space-vector diagram of a five-level inverter using calculated table into fully programming method. The execution time of the proposed method is about same as that of the method using calculated table. Also, the proposed method is easily applied to other case level inverter. We applied this method into the 3-phase IHCML inverter using common arm. It makes possible to use a single DC power source due to employing low frequency transformers. In this inverter, the number of transformers could be reduced compare with an exiting 3-phase multi-level inverter using single phase transformer. In addition, this method generates very low harmonic distortion operation with nearly fundamental switching frequency. Finally, We tested multi-level inverter to clarify electric circuit and reasonableness through Matlab simulation and experiment by using prototype inverter.
Thermal and Humidity Sensing Properties of Heat Resistant Polyimide Thin Film Manufactured by Dry Process
Lim, Kyung-Bum ; Kim, Ki-Hwan ; Hwang, Sun-Yang ; Kim, Jong-Yoon ; Hwang, Myung-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1080~1086
The aim of this paper is to establish the optimum fabrication condition of specimens, using the Vapor Deposition Polymerization Method(VDPM), which is one of modesto prepare functional organic thin films using a dry process, and to develop a thin film type humidity sensor which has good humidity sensitive characteristics. The inner part of the film became denser and roughness of the film surface eased as curing temperature increased so that thickness of the film could be made uniform. This also shows the appropriate curing temperature was
. The basic structure of the humidity sensor is a parallel capacitor which consists of three layers of Aluminum/Polyimide/Aluminum. The result of SEM and AFM measurement shows that the thickness of PI thin films decreased and the refraction increased as curing temperature increased, which indicates that a capacitance-type humidity sensor utilizing polyimide thin film is fabricated on a glass substrate. The characteristics of fabricated samples were measured under various conditions, and the samples had linear characteristics in the range of 20-80 %RH, independent of temperature change, and low hysteresis characteristic.
A Study on the Electrical Circuit Model of the Electrode/Electrolyte Interface for Improving Electrochemical Impedance Fitting
Chang, Jong-Hyeon ; Pak, Jung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1087~1091
Exact impedance modeling of the electrode/electrolyte interface is important in bio-signal sensing electrode development. Therefore, the investigation of the equivalent circuit models for the interface has been pursued for a long time by several researchers. Previous circuit models fit the experimental results in limited conditions such as frequency range, type of electrode, or electrolyte. This paper describes a new electrical circuit model and its capability of fitting the experimental results. The proposed model consists of three resistors and two constant phase elements. Electrochemical impedance spectroscopy was used to characterize the interface for Au, Pt, and stainless steel electrode in 0.9% NaCl solution. Both the proposed model and the previous model were applied to fit the measured impedance results for comparison. The proposed model fits the experimental data more accurately than other models especially at the low frequency range, and it enables us to predict the impedance at very low frequency range, including DC, using the proposed model.
A Study on the New Partial Discharge Pattern Analysis System used by PA Map (Pulse Analysis Map)
Kim, Ji-Hong ; Kim, Jeung-Tae ; Kim, Jin-Gi ; Koo, Ja-Yoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1092~1098
Since one decade, the detection of HFPD (High frequency Partial Discharge) has been proposed as one of the effective method for the diagnosis of the power component under service in power grids. As a tool for HFPD detection, Metal Foil sensor based on the embedded technology has been commercialized for mainly power cable due to its advantages. Recently, for the on-site noise discrimination, several PA (Pulse analysis) methods have been reported and the related software, such as Neural Network and Fuzzy, have been proposed to separate the PD (Partial Discharge) signals from the noises since their wave shapes are completely different from each other. On the other hand, the relevant fundamental investigation has not yet clearly made while it is reported that the effectiveness of the current methods based on PA is dependant on the types of sensors. Moreover, regarding the identification of the vital defects introducible into the Power Cable, the direct identification of the nature of defects from the PD signals through Metal Foil coupler has not yet been realized. As a trial for solving above shortcomings, different types of software have been proposed and employed without any convincing probability of identification. In this regards, our novel algorithm 'PA Map' based on the pulse analysis is suggested to identify directly the defects inside the power cable from the HFPD signals which is output of the HFCT and metal foil sensors. This method enables to discriminate the noise and then to make the data analysis related to the PD signals. For the purpose, the HFPD detection and PA (Pulse Analysis) system have been developed and then the effect of noise discrimination has been investigated by use of the artificial defects using real scale mockup. Throughout these works, our system is proved to be capable of separating the small void discharges among the very large noises such as big air corona and ground floating discharges at the on-site as well as of identifying the concerned defects.
Design of Microwave Unequal Power Dividers Using Defected Ground Structure
Lim, Jong-Sik ; Koo, Jae-Jin ; Oh, Seong-Min ; Ahn, Dal ; Choi, Kwan-Sun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1099~1104
A 1:6 Unequal 2-way Wilkinson power divider is proposed. The required microstrip line with
characteristic impedance for 1:6 power divider is realized by adding defected ground structure (DGS) to the standard microstrip line. The adopted DGS has the rectangular geometry which results in the increased characteristic impedance. The rectangular-shaped DGS produces the transmission line having much higher characteristic impedance due to the increased equivalent inductance. The measured performances of the fabricated 1:6 power divider show the expected S-parameters with a good agreement with the predicted ones.
Equivalent Circuit Model for Four Port Connector System
Shim, Min-Kyu ; Kim, Jong-Min ; Nah, Wan-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1105~1110
This paper describes an equivalent circuit modeling of 4-port connector system. A coupled transmission line was designed and fabricated, mimicking a 4-port connector system, and then S-parameters were measured using 4 port VNA (Vector Network Analyzer). The S-parameters from measurement and from Full-wave simulator coincided quite nice. By using these S parameters, an equivalent circuit parameters for a 4-port system was obtained. The time domain response from the equivalent circuit model matched to the signals, which was measured using TDR(Time Domain Reflectometry) meter. We were also convinced that there should be enough bandwidth to get a meaningful time domain result from Fourier inverse transformation of the S parameters. In addition, we applied the conversion algorithm to the 4-port connector system, which calculates the S-parameters of a 4 port system using the data from a 2-port VNA with the other ports open. Comparison of the two data, one from measurement and the other one from the conversion algorithm, was made in this manuscript.
Design and Implementation of Wideband Microstrip Antenna with Resistive and Inductive Loading
Jeon, Sang-Bong ; Ahn, Chang-Hoi ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1111~1116
Antennas of the near field detection radar require little distortion in time domain caused by multi reflections between feed and open ends of the antenna, so that help to discriminate the target signal from the clutters. The resistive loading techniques have been used to reduce the late time distortions in order to prevent masking of target. In this paper, we design a microstrip antenna with two arms having sloted lines, which have inductance loading effect. Implemented antenna shows better performance on reducing late-time ringing, and the peak value of the received signal becomes 45% greater than the one by the antenna with two non-sloted lines.
Fabrication and Output Characteristics of a High-Speed Wavelength Swept Mode-Locked Laser
Lee, Eung-Je ; Kim, Yong-Pyung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1117~1121
We demonstrate a wavelength swept mode-locked ring laser for the frequency domain optical coherence tomography(FD OCT). A laser is constructed by using a semiconductor optical amplifier, fiber Fabry-Perot tunable filter and 2.6 km fiber ring cavity. Mode-locking is implemented by 2.6 km fiber ring cavity for matching the fundamental or harmonic of cavity roundtrip time to a sweep period. The wavelength sweeps are repetitively generated with the repetition period of 77.2 kHz which is the parallel resonance frequency of Fabry-Perot tunable filter for the low driving current consumption of the fiber Fabry-Perot tunable filter. The wavelength tuning range of the laser is more than FWHM of 61 nm centered at the wavelength of 1320 nm and the linewidth of the source is
Determination of Optimal Checkpoint Interval for RM Scheduled Real-time Tasks
Kwak, Seong-Woo ; Jung, Young-Joo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1122~1129
For a system with multiple real-time tasks of different deadlines, it is very difficult to find the optimal checkpoint interval because of the complexity in considering the scheduling of tasks. In this paper, we determine the optimal checkpoint interval for multiple real-time tasks that are scheduled by RM(Rate Monotonic) algorithm. Faults are assumed to occur with Poisson distribution. Checkpoints are inserted in the execution of task with equal distance in the same task, but different distances in other tasks. When faults occur, rollback to the latest checkpoint and re-execute task after the checkpoint. We derive the equation of maximum slack time for each task, and determine the number of re-executable checkpoint intervals for fault recovery. The equation to check the schedulibility of tasks is also derived. Based on these equations, we find the probability of all tasks executed within their deadlines successfully. Checkpoint intervals which make the probability maximum is the optimal.
A Study on Display Data of Radiation Point at 3 Dimensions
Lee, Seung-Min ; Lee, Heung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1130~1132
In this research, 3D position exploring system was developed to detect direction and position of radiation source by using two general CCD camera. This system consists of a radiation detection device, a controlling device, and a monitoring device. A radiation detection device is composed of a collimator, a scintillator, CCD sensor, and radiation shielding part. Incident radiation is firstly collimated with direction and converted into visual lights in a scintillator. The CCD sensor detect the converted visual light and send a signal as an image. This can explore a radiation source with direction and distance from geometrical structure of two sensors. From these information, the developed 3D position exploring system can provide 3D radiation source information. This research will be useful for managing and processing radioactive materials in remote.
DLL Design of SMD Structure with DCC using Reduced Delay Lines
Hong, Seok-Yong ; Cho, Seong-Ik ; Shin, Hong-Gyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1133~1138
DLLs(Delay Locked Loops) have widely been used in many systems in order to achieve the clock synchronization. A SMD (Synchronous Mirror Delay) structure is used both for skew reduction and for DCC (Duty Cycle Correction). In this paper, a SMD based DLL with DCC using Reduced Delay Lines is proposed in order to reduce the clock skew and correct the duty cycle. The merged structure allows the forward delay array to be shared between the DLL and the DCC, and yields a 25% saving in the number of the required delay cells. The designed chip was fabricated using a
1-poly, 4-metal CMOS process. Measurement results showed the 3% duty cycle error when the input signal ranges from 80% to 20% and the clock frequency ranges from 400MHz to 600MHz. The locking operation needs 3 clock and duty correction requires only 5 clock cycles as feature with SMD structure.
Development of Wearable Electro-Stethoscope Hardware System for the Ubiquitous Healthcare
Kim, Dong-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1139~1143
For the possible application of monitoring or diagnosing heart sounds in an ubiquitous healthcare environment. a small and light electro-stethoscope that can be attached in human body should be exploited. With this aim, this study proposes a new style of electro-stethoscope device that is composed of four hardware modules in wearable style. For this ambulatory heart sound collecting device, the several tests must be performed to check portability and material capability for collecting heart sounds. It turned out to be that the multi-channel electro-stethoscope can detect heart sound signals well even if it is not pinpointed in the accurate stethoscope point on a heart. Consequently, our ambulatory electro-stethoscope hardware system can be applied to monitor or diagnose abnormal heart sounds in the ubiquitous healthcare system.
Real-time Biomedical Signal Visualization by ActiveX Modulation
Yoon, Tae-Ho ; Kim, Kyeong-Seop ; Shin, Seung-Won ; Lee, Jeong-Whan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1144~1150
In this study, a hardware-independent software scheme is proposed to visualize biomedical signals such as an electrocardiogram(ECG) and their relevant diagnostic features in a real-time mode. To minimize the dependency on a specific hardware units and to maximize software portability into the different hardware platforms, objected-oriented visualization codes are implemented by Visual C++ MFC(Microsoft Fundamental Classes) with the integration of ActiveX modules.
Improvement of a Binary ECG Conversion System Utilizing Compilation Technique
Koo, Heung-Seo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1151~1156
In this paper, we develop a new conversion method for implementing binary ECG(Electrocardiogram) conversion scheme to improve our previous research works that supported the conversion of binary ECG files into HL7 aECG for enhancing interoperability of ECG data. HL7 aECG is a XML-based standard for interoperability of ECG waveform. To improve the performance of ECG data conversion, we utilize a compilation-based ECG conversion method on binary ECG files. Our new method supports both flexibility of BED-based ECG conversion mechanism and the performance of direct conversion mechanism.
Development of Ambulatory Audiometric System by Sound Pressure Level Calibration
Shin, Seung-Won ; Kim, Kyeong-Seop ; Yoon, Tae-Ho ; Lee, Sang-Min ; Song, Chul-Gyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1157~1164
In this paper, we implement a PDA(Personal Digital Assistant)-based audiometric system in order to estimate hearing threshold by adopting both pure-tone sound and speech audiometric test system. To estimate a subject's hearing threshold in an ambulatory audiometric test environment, an efficient sound calibration scheme between a PDA and a headphone device is proposed by appling polynomial fitting algorithms in 8-banded frequency ranges.
A Study on the Temperature Measuring System of an Oral Cavity
Kim, Kyung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1165~1169
In this study, a novel sensor system for measuring the temperature inside an oral cavity is proposed. With this aim, a small size of thermistor was used for resolving the cavity's temperature with the resolution of
. To evaluate effectiveness of our sensor system, the temperature and its output voltage characteristic, and the specifications of response are investigated. It turned out to be that our sensor system has a linear property in terms of temperature variations for a healthy subject's body temperature range and has a good response time within 3 seconds. Also, in order to investigate the medical application, our sensor system is sought to measure the real temperature variations of a subject's oral cavity and ark shell especially for 'before' and 'after' exercise mode.
A New Approach Method of Measuring Abdominal Pressure for Urodynamic Monitoring System
Seo, Jeong-Hwan ; Kim, Keo-Sik ; An, Yang-Su ; Kim, Kyeong-Seop ; Song, Chul-Gyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 6, 2007, Pages 1170~1176
The conventional urodynamic monitoring is fulfilled by artificially filling a bladder with saline. Generally. it is difficult to evaluate the physiological functions of the storage and voiding of a bladder. With this aim, we constructed an ambulatory urodynamic monitoring (AUM) system and proposed a novel method estimating abdominal pressure by measuring bio-impedance variations. Our system was clinically evaluated for 10 patients. It turned out to be that as the intensity of the abdomen contraction increased, the amplitude of bio-impedance signal and the RMS value of EMG increased more as compared to those who observed during the rest mode. Also, we determined the optimum electrode pair for estimating the abdominal pressure using bio-impedance method and consequently compared with the conventional methods. Because impedance changes differ from a weight, a height, contractile force, volume of muscle and blood other or whatever of individuals, it was quantified in terms of impedance change, correlation coefficient and SNR Our results showed the optimum electrode pair (1,9) which could detect impedance changes due to the increase of the intensity in the abdominal pressure. The correlation coefficient and quadratic function between the RMS values of EMG and the impedance changes were 0.87 and
, respectively. Thus, our system demonstrated that the abdominal pressure could be measured noninvasively and conveniently by simply estimating bio-impedance values. We propose that this optimum electrode configuration would be useful for the future studies involving the handy measurements of abdominal pressure with our suggested ambulatory urodynamics monitoring system.