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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 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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Compensation of the Secondary Voltage of a Coupling Capacitor Voltage Transformer
Kang, Yong-Cheol ; Zheng, Tai-Ying ; Lee, Ji-Hoon ; Jang, Sung-Il ; Kim, Yong-Gyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 909~914
A coupling capacitor voltage transformer(CCVT) is used in an extra or ultra high voltage system to obtain the standard low voltage signal for protection. To avoid the phase angle error between the primary and secondary voltages, a tuning reactor is connected between a capacitor and a voltage transformer. The inductance of the reactor is designed based on the power system frequency. If a fault occurs on the power system, the secondary voltage of the CCVT contains some errors due to a dc offset component and harmonic components resulting from the fault. The errors become severe in the case of a close-in fault. This paper proposes an algorithm for compensating the secondary voltage of a CCVT in the time-domain. From the measured secondary voltage of the CCVT, the secondary and primary currents are obtained; then the voltage across the capacitor and the inductor is calculated and then added to the measured secondary voltage to obtain the correct primary voltage. Test results indicate that the proposed algorithm can compensate the distorted secondary voltage of the CCVT irrespective of the fault distance, the fault inception angle, and the burden of the CCVT.
Optimal Tuning of Nonlinear Parameters of a Dual-Input Power System Stabilizer Based on Analysis of Trajectory Sensitivities
Baek, Seung-Mook ; Park, Jung-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 915~923
This paper focuses on optimal tuning of nonlinear parameters of a dual-input power system stabilizer(dual-input PSS), which can improve the system damping performance immediately following a large disturbance. Until recently, various PSS models have developed to bring stability and reliability to power systems, and some of these models are used in industry applications. However, due to non-smooth nonlinearities from the interaction between linear parameters(gains and time constants of linear controllers) and nonlinear parameters(saturation output limits), the output limit parameters cannot be determined by the conventional tuning methods based on linear analysis. Only ad hoc tuning procedures('trial and error' approach) have been used. Therefore, the steepest descent method is applied to implement the optimal tuning of the nonlinear parameters of the dual-input PSS. The gradient required in this optimization technique can be computed from trajectory sensitivities in hybrid system modeling with the differential-algebraic-impulsive-switched(DAIS) structure. The optimal output limits of the dual-input PSS are evaluated by time-domain simulation in both a single machine infinite bus(SMIB) system and a multi-machine power system in comparison with those of a single-input PSS.
Path-dependency of Transmission Loss Allocation using Transaction Strategy
Min, Kyung-Il ; Ha, Sang-Hyeon ; Lee, Su-Won ; Moon, Young-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 924~931
This paper presents a buswise transmission loss allocation algorithm utilizing the transaction strategy. We prove that whatever calculated by any transaction strategy, the total of the allocated transmission losses of each bus, including no-load loss allocation, almost equals the total loss of AC power flow algorithm and the loss is perfectly slackbus-independent. In this paper, the allocated transmission losses of each bus is calculated by the method of integrating loss sensitivities using by the load level parameter
. The performance of the proposed algorithm is evaluated by the case studies carried out on the WSCC 9-bus and IEEE 14-bus systems.
Analysis of Power Quality by Transformer Inrush Current
Seo, Hun-Chul ; Yeo, Sang-Min ; Kim, Chul-Hwan ; Lyu, Young-Sik ; Cho, Burm-Sup ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 932~937
The transformer inrush current can cause a voltage drop by source impedance. This current can impact sensitive loads by the voltage drop. Therefore, it is necessary to take measures to limit this inrush current. This study, described in this paper, analyzes the power quality affected by transformer inrush current using the X power system in Korea. The Electromagnetic Transients Program(EMTP) is used to analyze the transient phenomenon. We discuss a method to model the hysteresis curve of the transformer in EMTP. We carried out various simulations to analyze the power quality during transformer energization. The analysis results of voltage drop by the inrush current occurrence when certain requirements are met are presented.
Compensation of the Secondary Voltage of a Three Winding Coupling Capacitor Voltage Transformer
Kang, Yong-Cheol ; Kim, Yeon-Hee ; Zheng, Tai-Ying ; Jang, Sung-Il ; Kim, Yong-Gyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 938~943
Coupling capacitor voltage transformers(CCVTs) have been used in extra or ultra high voltage systems to obtain the standard low voltage signal for protection and measurement. For fast suppression of the phenomenon of ferroresonance, three winding CCVTs are used instead of two winding CCVTs. A tuning reactor is connected between a capacitor voltage divider and a voltage transformer to reduce the phase angle difference between the primary and secondary voltages in the steady state. Slight distortion of the secondary voltage is generated when no fault occurs. However, when a fault occurs, the secondary voltage of the CCVT has significant errors due to the transient components such as dc offset component and/or high frequency components resulting from the fault. This paper proposes an algorithm for compensating the secondary voltage of a three winding CCVT in the time domain. With the values of the measured secondary voltage of the three winding CCVT, the secondary, tertiary and primary currents and voltages are estimated; then the voltages across the capacitor and the tuning reactor are calculated and then added to the measured voltage. Test results indicate that the algorithm can successfully compensate the distorted secondary voltage of the three winding CCVT irrespective of the fault distance, the fault impedance and the fault inception angle as well as in the steady state.
A Study of Verification on Application of Directional OCR and OCGR for Power System with Small Scale Cogeneration
Lee, Hee-Tae ; Cho, Man-Young ; Kim, Jae-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 944~950
When small cogenerators are operated in connected with power system, there are many positive aspects such as the reduction of power plant construction, making a improvement of power security etc. At the same time, there are some negative effects or difficulties such as we should make sure of protective coordination, especially, Actually these are not fault, but it is likely to consider the current as the fault. This is one of major causes of malfunctions for protective relays in power distribution system which is including interconnection point. Thus, in this paper, We showed that the directional protection is necessary to the dispersed generation system which is including connection point. We also executed contingency analysis to find out the magnitude of fault current and direction which are classified by fault points, length of line and kinds of faults using ETAP power system analysis program.
Development of Hardware Simulator for PMSG Wind Power System
Lee, Doo-Young ; Yun, Dong-Jin ; Jeong, Jong-Kyou ; Yang, Seung-Chul ; Han, Byung-Moon ; Song, Seung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 951~958
This paper describes development of hardware simulator for the PMSG wind power system, which was designed considering wind characteristic, blade characteristic and blade inertia compensation. The simulator consists of three major parts, such as wind turbine model using induction motor, PMSG generator, converter-inverter set. and control system. The turbine simulator generates torque and speed signals for a specific wind turbine with respect to given wind speed. This torque and speed signals are scaled down to fit the input of 2kW PMSG. The PMSG-side converter operates to track the maximum power point, and the grid-side inverter controls the active and reactive power supplied to the grid. The operational feasibility was verified by computer simulations with PSCAD/EMTDC, and the implementation feasibility was confirmed through experimental works with a hardware set-up.
Notch Design for Cogging Torque Reduction of Interor type Permanent Magnet Synchronous Motor
Han, Kwang-Kyu ; Ahn, Ho-Jin ; Kang, Gyu-Hong ; Jang, Ki-Bong ; Kim, Gyu-Tak ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 959~965
This paper presents a novel method for cogging torque reduction of interior type permanent magnet motor. For calculation position and width of notch, energy formulation and cogging torque function in air gap are analyzed by analytical method(space harmonics method) and numerical method. The optimal shape of notchs is decided by using finite element method. The validity of the proposed method is confirmed with experiments.
Starting Mode Analysis of Flat-type Linear Generator for Free-Piston Engine
Kim, Young-Wook ; Lim, Jae-Won ; Jung, Hyun-Kyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 966~971
Free-piston engine system is a new type energy converter which uses a linear motion of piston by using linear generator. In free-piston engine system, the piston is not connected to a crank-shaft. The major advantages of free-piston engine system are high efficiency and low mechanical loss from the absence of motion conversion devices. Linear generator of free-piston engine system is used as generator and starting motor. In design step, considering of back-emf and detent force characteristics for generating mode and thrust and control characteristics for starting mode is needed. In this research, generating mode of flat-type linear generator and tubular-type linear generator is analyzed by finite element analysis method and starting mode of both type linear generators is analyzed by using capability curve. Capability curve is plotted from electrical parameters of both type linear generator and motion profile is calculated from mechanical parameters.
A Study on the Three-Level Converter using Primary Auxiliary Circuit
Bae, Jin-Yong ; Kim, Yong ; Cho, Kyu-Man ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 972~981
A New ZVS(Zero Voltage Switching) and ZVZCS(Zero Voltage and Zero Current Switching) Three-Level Converter is proposed. The proposed converter presented in this paper used a phase shift control with a flying capacitor in the primary side to achieve ZVS for the all switch. A primary auxiliary circuit, which consists of one coupled inductor, is added in the primary to provide ZVZCS conditions to primary switches. Many advantages including simple circuit topology high efficiency, and low cost make this converter attractive for high power applications. The principle of operation, feature and design considerations are illustrated and verified through the experiment with a 2kW(27V, 74A) 40 kHz IGBT based experimental circuit.
A High-Gain Boost Converter using Voltage-Stacking Cell
Lee, Jun-Young ; Hwang, Sun-Nam ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 982~984
This paper suggests anon-isolated high-gain boost converter using voltage-stacking cell. The voltage gain can be increased by adjusting number of voltage-stacking cells and transformer turns-ratio. Test results with 1kW prototype converter show that the voltage gain is three or four times higher than conventional boost converter at unity transformer turns-ratio and about 90% of efficiency is recorded under full load condition.
Wind Power System using Doubly-Fed Induction Generator and Matrix Converter
Lee, Dong-Geun ; Kwon, Gi-Hyun ; Han, Byung-Moon ; Li, Yu-Long ; Choi, Nam-Sup ; Choy, Young-Do ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 985~993
This paper proposes a new DFIG(Doubly-Fed Induction Generator) system using matrix converter, which is very effectively used for interconnecting the wind power system to the power grid. The operation of proposed system was verified by computer simulations with PSCAD/EMTDC software. The feasibility of hardware implementation was conformed by experimental works with a laboratory scaled-model of wind power system. The laboratory scaled-model was built using a motor-generator set with vector drive system, and a matrix converter with DSP(Digital Signal Processor). The operation of scaled-model was tested by modeling the specific variable-speed wind turbine using the real wind data in order to make the scaled-model simulate the real wind power system as close as possible. The simulation and experimental results confirm that matrix converter can be applied for the DFIG system.
Control of a Novel PV Tracking System Considering the Shadow Influence
Park, Ki-Tae ; Choi, Jung-Sik ; Chung, Dong-Hwa ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 994~1002
In this paper a novel tracking system is described, regarding the influence of shadow between array, aimed at improving the efficiency of PV tracking system. Comparing with a building site versus capacity power, domestic solar powers have a limited siting. Therefore, each array interferes with the shadow of other arrays. The loss by influence of those shadow can be compensated for by means of control algorithm of the tracking device. The paper suggests a method controlling an altitude for length which is received the shadow influence of PV array. By using an azimuth of current solar position and the length between arrays, the controller of tracking device is able to calculate the length between actual arrays and make a comparison of the shadow length at a specific time with the length between arrays. When the shadow length is longer than the length between arrays, the controller of tracking device can adjust a position by compensating error altitude of the length between arrays at an altitude of current solar position. In the paper, we develop the control algorithm able to minimize the loss caused by the influence of shadow on the PV tracking system, and compared this with conventional output system. The controller has been tested in the laboratory with proposed algorithm and shows excellent performance.
Optimal Design of Interleaved Boost Converters for Fuel Cell Applications
Choe, Gyu-Yeong ; Kim, Jong-Soo ; Kang, Hyun-Soo ; Lee, Byoung-Kuk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1003~1011
In this paper, optimal design of interleaved boost converters is studied in order to design low ripple, size, loss and high performance converters for fuel cell applications. Also, the process of optimal design of interleaved boost converter has been performed. Input current ripple, output voltage ripple, losses and capacity of electrical components are theoretically analyzed and informative simulation and experimental results are provided.
A Study on the Electrical Properties of Thin Film Type Humidity Sensor
You, Do-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1012~1016
] sol was fabricated using sol-gel method and
thin films were fabricated using dip-coating method.
sol was added 0.01mole, 0.03mole, 0.05mole into
sol. As a results of crystalline properties,
peaks were not found in spite of
additive. Thickness of thin films increased
every a dipping. Capacitance of thin films increased with increasing heat treatment temperature and it increased largest at
. Capacitance of thin films decreased with increasing
additive and it increased largest at 0.01mole. Because adsorption time and desorption time of thin films was about 2 minutes 40 seconds and about 3 minutes 40 seconds respectively, adsorption time was faster about 1 minutes than desorption time.
Development of a Calculable Potential Transformer with Wide Ratio Error
Kwon, Sung-Won ; Jung, Jae-Kap ; Lee, Sang-Hwa ; Kim, Myung-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1017~1021
A calculable potential transformer(PT) with nominal ratio error in wide range of -10% to +10% has been developed on basis of theoretical calculation of ratio error by the number of windings. The developed PT can be used to evaluate the linearity and accuracy of the PT comparator by comparing both the theoretical and experimental values of the PT which have exactly same ratio errors in nominal and calculated values. The PT has been applied for calibration and correction of the PT comparator up to wide ratio error range of -10% to +10%. This portable PT is very convenient to carry to the power industry for the on-site calibration of the PT comparator.
A study on High Voltage Squarewave Pulse Generator
Kim, Young-Bae ; Ryu, Hong-Je ; Kim, Jong-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1022~1025
This paper presents the generation of the high voltage squarewave pulse using distributed RLC circuit. The demonstrated test was performed with the distributed RLC circuit which consists of the resistance, the inductance and the capacitance. Pspice simulation was also conducted about the experiment circuit. The result of the experiment was in good agreement with the result of the simulation. Theoretical analysis of the initial peak value at the squraewave pulse was derived from the results of the experiment and simulation. Additionally, the characteristics of the time delay was analyzed about the spherical gap switch and the surface discharge gap switch, respectively. It is concluded that the surface discharge gap switch is better than the spherical gap switch to reduce the time delay.
Design of the Large Diameter Faraday Rotator for High-power Laser Systems
Hong, Sung-Ki ; Seo, Young-Seok ; Ko, Kwang-Hoon ; Kim, Young-Won ; Wee, Sang-Bong ; Lim, Chang-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1026~1031
We report on the design and experimental results of a large diameter faraday rotator for the high-power laser system(KLF: Kaeri laser facility) that was completed in late 2007s at Korea Atomic Energy Research Institute. The design involves modelling the magnetic field of cylindrical coil with large diameter(110 mm). Magnetic field generation coil is designed by 6 layers using a rectangular wire with cross-sectional area
. We obtain an isolation ratio for optical feedback of 35 dB at 1064 nm and magnetic field strengths
. We expect that the design can be widely used optical isolators in high-power laser system.
Efficient DC Power Management Scheme using 60-GHz Rectenna
Lim, Sung-Joon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1032~1035
In this paper, a DC power management scheme is proposed for efficient battery operation of 60-GHz receivers. It consists of a rectenna and a zero-cross detector. The harmonic rejection capability of a circular sector antenna is used to simplify the rectenna. The zero-cross detector is introduced to increase sensitivity. When the received power density is larger than 0.013
, it can generate enough DC power to activate an RF receiver. Experimental data is used to verify the proposed idea.
Adaptive State Feedback Control System of DC Motors with Periodic Random Disturbance
Jeong, Sang-Chul ; Kim, Jun-Su ; Cho, Hyun-Cheol ; Lee, Hyung-Ki ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1036~1041
Periodic disturbance is practically occurred in several engineering applications, especially in data storage systems. However, recently addressed controls for such problem were mostly dealt with its deterministic nature, which is rarely practical in real-time implementation. We present an adaptive control approach for DC motor systems with periodic stochastic disturbance whose frequency and magnitude are both random variables. We establish adaptive state feedback control which is linearly composed of nominal and corrective control parameter matrices. The former is derived from a nominal system model voiding disturbance and the latter is constructed from a disturbed system model by using Lyapunov stability theory. We carry out computer simulation to evaluate the proposed control methodology and compare to the recently addressed control method to demonstrate its superiority.
Adaptive Error Compensation of Heterodyne Laser Interferometer using DFNN
Heo, Gun-Haeng ; Lee, Woo-Ram ; You, Kwan-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1042~1047
As an ultra-precision measurement system the heterodyne laser interferometer plays an important role in semiconductor industry. However the errors of environment and nonlinearity which are caused by air refraction and frequency-mixing separately reduce the accuracy of displacement measurement. In this paper we propose a DFNN(data fusion and neural network) method for error compensation. As a hybrid method of data fusion and neural network, DFNN method reduces the environmental and nonlinear error simultaneously. The effectiveness of the proposed error compensation method is proved through experimental results.
Design of Low Order Cascade Controller to Reduce the Effects of Its Zeros
Kim, Young-Chol ; Kim, Jae-Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1048~1057
This paper represents a design method for PID or low-order controllers cascaded with a linear plant in the unit feedback system where it is required to meet the given time response specifications such as overshoot and settling time. This problem is difficult to solve because the zeros of the controller appear in the numerator of the overall system and thus those zeros may make the time response design difficult. In this paper, we propose a new approach based on the partial model matching and the so called K-polynomial. The partial matching problem is formulated to an optimization problem in which a quadratic function of coefficient errors between a target model and the resulting closed loop system is minimized. For the sake of satisfying the closed loop stability, a set of quadratic constraints associated with the cost function is introduced. As a result, the controller designed meets both time response requirements and the closed loop stability, if any. It is shown through several examples that the present method can be easily applied to these problems.
Application of Random Forest Algorithm for the Decision Support System of Medical Diagnosis with the Selection of Significant Clinical Test
Yun, Tae-Gyun ; Yi, Gwan-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1058~1062
In clinical decision support system(CDSS), unlike rule-based expert method, appropriate data-driven machine learning method can easily provide the information of individual feature(clinical test) for disease classification. However, currently developed methods focus on the improvement of the classification accuracy for diagnosis. With the analysis of feature importance in classification, one may infer the novel clinical test sets which highly differentiate the specific diseases or disease states. In this background, we introduce a novel CDSS that integrate a classifier and feature selection module together. Random forest algorithm is applied for the classifier and the feature importance measure. The system selects the significant clinical tests discriminating the diseases by examining the classification error during backward elimination of the features. The superior performance of random forest algorithm in clinical classification was assessed against artificial neural network and decision tree algorithm by using breast cancer, diabetes and heart disease data in UCI Machine Learning Repository. The test with the same data sets shows that the proposed system can successfully select the significant clinical test set for each disease.
Design of BACnet/Zigbee Intrated System
Kim, Se-Hwan ; Park, Dong-Kyu ; Hong, Seung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1063~1068
BACnet(Building Automation and Control Networks) is a standard data communication protocol specifically designed for building automation and control systems, BACnet provides six options for data link layer protocols and these six data link layer options can be applied with various wired transmission media. Recently wireless technology prevails in automation area. ZigBee is an IEEE 802.15.4 based standard communication protocol for low-rate wireless personal area networks. In this study, we propose a BACnet over ZigBee model that adopts ZigBee communication channel as a wireless data link layer protocol in a BACnet-based communication network system. The technology proposed in this paper can expand the BACnet application using the advantages of wired and wireless integrated network solution.
An Efficient OCT Architecture for Image Compression Applications
Yu, Sung-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1069~1074
This paper presents an efficient architecture for
-point DCT algorithm. The proposed approach makes use of the fact that, in most DCT applications, the scaling operation in the DCT unit can be eliminated and combined with the scaling operation in the quantizer unit. This important property is efficiently exploited with the CORDIC(COordinate Rotation DIgital Computer) algorithm to produce a regular architecture suitable for VLSI implementation. Although there have been several attempts to exploit CORDIC algorithm in developing DCT architectures, the proposed approach provides the most efficient way for scaled DCT applications by completely eliminating the scale factor compensation.
Parallel Processing Algorithm of JPEG2000 Using GPU
Lee, Dong-Ha ; Cho, Shi-Won ; Lee, Dong-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1075~1080
Most modem computers or game consoles are well equipped with powerful graphics processing units(GPUs) to accelerate graphics operations. However, since the graphics engines in these GPUs are specially designed for graphics operations, we could not take advantage of their computing power for more general nongraphic operations. In this paper, we studied the GPUs graphics engine in order to accelerate the image processing capability. Specifically, we implemented a JPEC2000 decoding/encoding framework that involves both OpenMP and GPU. Initial experimental results show that significant speed-up can be achieved by utilizing the GPU power.
The Design of 1.2V
Order 4bit Sigma Delta Modulator with Improved Operating Time of High Speed DWA
Yi, Soon-Jai ; Kim, Sun-Hong ; Cho, Sung-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1081~1086
This paper presents the
4bit sigma delta modulator with the block and timing diagrams of DWA(Data Weighted Averaging) to optimize a operating time. In the modulator, the proposed DWA structure has a stable operation and timing margin so as to remove three latches and another clock. Because the modulator with proposed DWA structure improve timing margin about 23%. It can increase sampling frequency up to 244MHz. Through the MATLAB modeling, the optimized coefficients are obtained to design the modulator. The fully differential SC integrators, DAC, switch, quantizer, and DWA are designed by considering the nonideal characteristics. The designed
order 4bit modulator has a power consumption of 40mW and SNR(signal to noise ratio) of 77.2dB under 1.2V supply and 64MHz sampling frequency.
Development of a Human Sensibility Evaluation and Biofeedback System using PPG
Lee, Hyun-Min ; Kim, Dong-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1087~1094
This study describes a system for human sensibility evaluation using PPG(photoplethysmogram) signal and biofeedback algorithm to respond the bad(negative) mood. For this objective, PPG signals for two emotional states(positive/negative) are collected. To evoke the test emotions, happy(or joyful) and sad(or irritating) movie files are collected and played in subjects' monitor. From the acquired PPG signal, the heart rate variability(HRV) is calculated. Using the HRV and its FFT spectra, the human sensibility is evaluated. Since the heart is a representative organ which is controlled by the autonomic nervous system(ANS), the ANS may reflect the changes in emotion. The biofeedback algorithm is designed with motion image player interacting with the results of the sensibility evaluation. It was shown that HRV was changed according to the subject's emotions. Accordingly, the sensibility evaluation test showed feasibility of the our method.
Estimation of Systolic Blood Pressure using PTTL
Kil, Se-Kee ; Kwan, Jang-Woo ; Yoon, Kwang-Sub ; Lee, Sang-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1095~1101
The desirable method to diagnose abnormal blood pressure is to measure and manage blood pressure continuously and regularly. However, the sphygmomanometers that are based on a cuff have faults in that they can not measure the blood pressure continuously and they cause an unpleasant feeling. Therefore, it is essential to develop a new measuring method that causes no pain and that can obtain blood pressure continuously without any unpleasant feeling. Thus, we propose here a regression method to estimate the systolic blood pressure by using the PTTL(pulse transit time on leg) with some body parameters which are chosen from the relational analysis with systolic blood pressure. The data we use to make the regression model were obtained in triplicate from each of 50 males who were from 18 to 35 years. And we made estimation experiments of blood pressure on 10 males who did not take part in the making the regression model. According to the results, the proposed method showed a mean error of 4.00 mmHg and the standard variance was 2.45 mmHg. When we comparing the results of the proposed method with the rule of American National Standards Institute of the Association of the Advancement of Medical Instruments(ANSI/AAMI), the results satisfied the rule of a mean error less than 5 mmHg and a standard variance less than 8 mmHg. Therefore we were able to validate the usefulness of the proposed method.
Implementation of Wearable Heart Activity Monitoring System having Modified Bipolar Electrode and Correlation Analysis with Clinical Electrocardiograph(ECG)
Lee, Kang-Hwi ; Lee, Jeong-Whan ; Lee, Young-Jae ; Kim, Kyeong-Seop ; Yang, Heui-Koung ; Shin, Kun-Su ; Lee, Myoung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1102~1108
Wearable physiological signal monitoring systems are regarded as an important sensing unit platforms in ubiquitous/mobile healthcare application. In this paper, we suggested the modified bipolar electrodes implemented on the portable heart activity monitoring system, which minimized the distance of electrodes formed on a attachable pad. The proposed electrode configuration is useful in mobile measurement environments, but has a disadvantage of reduced amplitude of the heart action potential. In order to overcome the shortcoming of the suggested electrode configuration, we implemented the amplifying circuit to increase the signal-gain and decrease the artifacts. For evaluations, we analyzed the specificity of measured cardiography using the proposed electrodes through the comparing of heart activity monitoring system with standard clinical ECG(lead2) by pearson correlation coefficients. The result showed that the average correlation coefficient is
at V3, V4 chest lead position, respectively. Thus, the modified bipolar electrode is quite suitable to monitor the electrical activity of the heart in the situation of the mobile environment, and could be considered having high similarity with standard clinical ECG.
The Assessment of Dynamic Mental Stress with Wearable Heart Activity Monitoring System
Kim, Kyeong-Seop ; Shin, Seung-Won ; Lee, Jeong-Whan ; Choi, Hee-Jung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1109~1115
In the ubiquitous health monitoring environments, it is quite important not only to evaluate the physiological health condition but also mental stress condition. In order to achieve this goal, a heart activity monitoring system utilizing a wearable bipolar electrode is devised and the heart rate variability(HRV) is extracted and interpreted in both frequency and time feature domains. Consequently, to evaluate the emotional stress condition of the subjects, a stress-induced experimental protocol was applied to healthy subjects and the time and frequency features of heart activity were analyzed in terms of the ratio of low frequency components v.s., high frequency components and the relevant the moving average distributions compromising the successive RR peaks intervals in the ambulatory ECG measurement system.
Measurement of Stride Length Using Optical Method
Jung, Gu-In ; Jun, Jae-Hoon ; Lee, Kang-Hwi ; Song, Min-Sun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 6, 2008, Pages 1116~1122
Since conventional methods for measuring stride length(distance) are many weaknesses, optical methods have been developed to measure stride length(distance) of human pedestrians. IR(Infrared) elements and Power LED(Light Emitting Diode) with two types of lens were used to correlate detected light intensity with stride length(distance). The suggested methods in this study are simple, convenient, and cost effective. The results can be used to analyze walking patterns of normal and disabled men, and to monitor the recovering processes of the disabled patients.