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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 57, Issue 12 - Dec 2008
Volume 57, Issue 11 - Nov 2008
Volume 57, Issue 10 - Oct 2008
Volume 57, Issue 9 - Sep 2008
Volume 57, Issue 8 - Aug 2008
Volume 57, Issue 7 - Jul 2008
Volume 57, Issue 6 - Jun 2008
Volume 57, Issue 5 - May 2008
Volume 57, Issue 4 - Apr 2008
Volume 57, Issue 3 - Mar 2008
Volume 57, Issue 2 - Feb 2008
Volume 57, Issue 1 - Jan 2008
Selecting the target year
Imperfect Preventive Maintenance Plan of Generation Unit Using Quasi-renewal Theory
Kim, Hyung-Jun ; Byun, Yoong-Tae ; Kim, Jin-O ; Lee, Jun-Kyong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 735~740
Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. For the most of the current power equipment maintenance, the state of the equipment after maintenance is assumed to be becoming 'as good as new ones' state. However, the state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.
Development of the Ubiquitous-based Intelligent Digital Switchgear Panel for Home Automation
Ko, Yun-Seok ; Kim, Ho-Yong ; Yun, Seok-Yeul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 741~747
This paper proposes a new concept of IDSP(Intelligent Digital Switchgear Panel) which can solve the problem of the safety, the reliability and the convenience to correspond to the requirement of the general electric customer or electric power company under the ubiquitous-based home automation environments. By analyzing their requirement functions, a 32-bit micro processor is adopted as main controller to support the designed functions efficiently. The DSP-based single phase power management device is utilized to collect the electric power information and the ethernet convertor to communicate through internet among the IDSPs and the remote computer system. In the proposed IDSP, the several functions are implemented such as the earth leakage level display and waveform transmission, the electric fee display, the voltage management, the load management and the load control function. Finally, the prototype of the IDSP is made experimently based on the designed results, and then the effectiveness is verified by testing its basic functions.
A Global Optimization Technique for the Capacitor Placement in Distribution Systems
Rhee, Sang-Bong ; Kim, Kyu-Ho ; Lee, Sang-Keun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 748~754
The general capacitor placement problem is a combinatorial optimization problem having an objective function composed of power losses and capacitor installation costs subject to bus voltage constraints. In this paper, a global optimization technique, which employing the chaos search algorithm, is applied to solve optimal capacitor placement problem with reducing computational effort and enhancing global optimality of the solution. Chaos method in optimization problem searches the global optimal solution on the regularity of chaotic motions and easily escapes from local or near optimal solution than stochastic optimization algorithms. The chaos optimization method is tested on 9 buses and 69 buses system to illustrate the effectiveness of the proposed method.
Analysis on the Protective Coordination in Power Distribution System with Superconducting Fault Current Limiter
Ahn, Jae-Min ; Kim, Jin-Seok ; Moon, Jong-Fil ; Lim, Sung-Hun ; Kim, Jae-Chul ; Kim, Chul-Hwan ; Hyun, Ok-Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 755~760
The increase of fault current due to larger power demand has caused the capacity of power machines in grid to increase. To protect the power system effectively from the larger fault current, several countermeasures have been proposed. Among them, the superconducting fault current limiter (SFCL) has been expected as one of the most effective solutions. Therefore, to introduce SFCL into power distribution system, the analysis on protection in power distribution system with SFCL is essential. In this paper, the problems of the protective coordination in power distribution system with SFCL were described.
Compensation Algorithm for a Measurement Voltage Transformer
Kang, Yong-Cheol ; Park, Jang-Min ; Lee, Mi-Sun ; Jang, Sung-Il ; Kim, Yong-Gyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 761~766
This paper describes a compensation algorithm for a measurement voltage transformer (VT) based on the hysteresis characteristics of the core. The error of the VT is caused by the voltages across the primary and secondary windings. The latter depends on the secondary current whilst the former depends on the primary current, i.e. the sum of the exciting current and the secondary current. The proposed algorithm calculates the voltages across the primary and secondary windings and add them to the measured secondary voltage for compensation. To do this, the primary and secondary currents should be estimated. The secondary current is obtained directly from the secondary voltage and used to calculate the voltage across the secondary winding. For the primary current, in this paper, the exciting current is decomposed into the two currents, i.e. the core-loss current and the magnetizing current. The core-loss current is obtained by dividing the primary induced voltage by the core-loss resistance. The magnetizing current is obtained by inserting the flux into the flux-magnetizing current curve. The calculated voltages across the primary and secondary windings are added to the measured secondary current for compensation. The proposed compensation algorithm improves the error of the VT significantly.
Development of IEC 61850 Performance Testing Procedures of BUS Protection IED Using UML
Lee, Nam-Ho ; Jang, Byung-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 767~772
Korea Electric Power Research Institute in charge of the power IT project "Development of Prototype for Advanced Substation Automation System based on the Digital Control Technology", is performing the verification of performance of the substation automation system. In order to verify a system based BUS protection IED, the standardized document and procedures are required. But there is nothing to describe systematically how to verify IEC 61850 based IED in the system environment except an individual IED testing way and report. This paper presents the substation automation system based ways and procedures to verify the IED using UML(Unified Modelling Language).
Field Test and Analysis for Proper Location of Protective Equipment in Underground Distribution System
Yun, Chang-Sub ; Lee, Jong-Beom ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 773~782
This paper describes the method for proper location of protective equipment in underground distribution cable through field test and analysis at testing lines. To prove the reliability for analysis simulated by EMTP/ATPDraw, the testing results obtained by the real test and the analysis for the same test lines were compared each other. The accuracy of analysis was proved by the comparison. Over voltages were measured and analyzed at each point of cable and switches in case of which lightning surge current was applied. The analysing method was applied to real distribution systems to select the proper location of protective equipment. It is evaluated that the location of protective equipment was properly selected.
Optimal Design of Electro-Permanent Magnet Lifter Using Improved Auto-Tuning Niching Genetic Algorithm
Lee, Bum-Joo ; Seo, Jang-Ho ; Kwak, Sang-Yeop ; Lee, Sang-Yeop ; Jung, Hyun-Kyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 783~788
This paper presents the mechanism of the machine and the numerical result of attractive force in the Electro-Permanent Magnet Lifter (EPML) and an improved niching Genetic Algorithm (GA) applying the concept of auto-tuning and detecting traces. Population size and both (right and left) niche radii of each peak in an asymmetrical objective function can be determined automatically. The validity of the proposed method is verified by simulation results.
Single-Phase Active Power Filter based on Digital Controller
Bae, Byung-Yeol ; Lee, Ji-Heon ; Lee, Hye-Yeon ; Ju, Young-Ah ; Han, Byung-Moon ; Park, Byung-Ju ; Yoon, Dong-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 789~796
This paper describes a single-phase active power filter based on a newly developed digital controller. The developed controller utilizes FFT(Fast Fourier Transform) algorithm to extract the reference signal from the load current, considering the phase-angle delay of each order of harmonics. Optimized technique was applied for whole control algorithm to implement the real-time operation of developed controller. The performance of developed controller for a single-phase active power filter was verified through computer simulations with PSCAD/EMTDC. The feasibility of hardware implementation was confirmed by building and testing a prototype. The developed digital controller for a single-phase active power filter can compensate the harmonic current generated by the power supply for digital equipment.
Decision of SSI Network dimension for Safety based ODLM(LDT) installation
Min, Geun-Hong ; Lee, Jong-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 797~802
High Speed Rail Train Control System consists of CTC, IXL and ATC. IXL and ATC perform train control and command via interchanging relevant information between a signal room and CTC. However, it is proved that IXL and ATC are attributed to train delay error since those systems are highly sensitive to trackside conditions. Especially, network error on IXL blocks transmitting signal information to adjacent signal room so that its effects give rise to system overall problems. In order to figure out the measures for which minimizing the occurrence rate of train delay error due to HSR TCS, This paper is performed analysis on communication network structure, the length of SSI network roof and SSI-TFM distance by examining and analyzing the error cases related to IXL in a network aspect.
A Study of Photo-electric Efficiency Improvement using Ultrasonic and Thermal Treatment on Photo-electrode of DSC
Kim, Hee-Je ; Kim, Yong-Chul ; Choi, Jin-Young ; Kim, Ho-Sung ; Lee, Dong-Gil ; Hong, Ji-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 803~807
A making process of DSC(dye sensitized solar cell) was presented. In general, Photo electrodes of DSC was made by using colloid paste of nano
and processing of Doctor-blade printing and high temperature sintering for porous structure. These methods lead to cracks on
surface and ununiform of
thickness. This phenomenon is one factor that makes low efficiency to cells. After
printing on TCO glass, a physical vibration was adapted for reducing ununiform of
thickness. And a thermal treatment at low temperature(under
) was adapted for reducing cracks on
surface. In this paper, we have designed and manufactured an ultrasonic circuit (100W, frequency and duty variable) and a thermal equipment. Then, we have optimized forcing time, frequency and duty of ultrasonic irradiation and thermal heating for surface treatment of photo-electrode of DSC. In I-V characteristic test of DSC, ultrasonic and thermal treated DSC shows 19% improved its efficiency against monolithic DSC. And it shows stability of light-harvesting from drastically change of light irradiation test.
Effects of In Situ YAG on Properties of the Pressurless Annealed Sic-
Electroconductive Ceramic Composites
Shin, Yong-Deok ; Ju, Jin-Young ; Ko, Tae-Hun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 808~815
The composites were fabricated 61[vol.%]
-SiC and 39[vol.%]
powders with the liquid forming additives of 8, 12, 16[wt%]
as a sintering aid by pressureless annealing at 1650[
] for 4 hours. The present study investigated the influence of the content of
sintering additives on the microstructure, mechanical and electrical properties of the pressureless annealed SiC-
electroconductive ceramic composites. Reactions between SiC and transition metal
were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-
electroconductive ceramic composites. Phase analysis of SiC-
composites by XRD revealed mostly of
, and In Situ YAG(
). The relative density of SiC-
composites was lowered due to gaseous products of the result of reaction between SiC and
. There is another reason which pressureless annealed temperature 1650[
] is lower
than applied pressure sintering temperature
. The relative density, the flexural strength, the Young's modulus and the Vicker's hardness showed the highest value of 82.29[%], 189.5[Mpa], 54.60[Gpa] and 2.84[Gpa] for SiC-
composites added with 16[wt%]
additives at room temperature. Abnormal grain growth takes place during phase transformation from
-SiC was correlated with In Situ YAG phase by reaction between
additive during sintering. The electrical resistivity showed the lowest value of 0.0117[
] for 16[wt%]
additives at 25[
]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from
]. The resistance temperature coefficient of composite showed the lowest value of
for 16[wt%] additives in the temperature ranges from 25[
] to 100[
Electromagnetic Simulation & Electrical.Optical Characteristics by Changing Ferrite Position in Antenna
Lee, Joo-Ho ; Yang, Jong-Kyung ; Lee, Jong-Chan ; Choi, Myung-Hyun ; Kim, Byung-Tack ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 816~820
The RF inductive discharge of inductively couples plasma (ICP) continues to attract growing attention as an effective plasma source in many industrial applications, the best known of which are plasma processing and lighting technology. Although most practical ICPs operate at 13.56 [MHz] and 2.65 [MHz], the trend to reduce the operating frequency is clearly recognizable from recent ICP developments. In an electrodeless fluorescent lamp, the use of a lower operating frequency simplifies and reduces cost of RF matching systems and RF generators and can eliminate capacitive coupling between the inductor coil and plasma, which could be a strong factor in wall erosion and plasma contamination. In this study, We discussed simulation and experimental results when changing ferrite position in antenna.
Operational Characteristics Analysis of Circuits with Active Element on Electromagnetic Topolgy
Kwon, Oh-Wook ; Park, Yoon-Mi ; Chung, Young-Seek ; Cheon, Chang-Yul ; Jung, Hyun-Kyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 821~826
Recently as a progress of electric technology, modern electric systems become more and more complicated. Thus, it is difficult to use a classical method to analyze responses of the systems in complicated electromagnetic environments because there are so many coupling phenomena. The electromagnetic topology (EMT) is a helpful solution to analyze electromagnetic interference / electromagnetic compatibility (EMI/EMC) of the large complex system. In this paper, EMT is applied to analyze an active element. And then to prove the validity of this analysis, a detector circuit including Schottky barrier diode is analyzed by EMT when input power is given directly.
The New Structure in AC PDP with Long Discharge Gap for High Luminance and Luminous Efficacy
Dong, Eun-Joo ; Ok, Jung-Woo ; Lee, Don-Kyu ; Lee, Hae-June ; Lee, Ho-Joon ; Park, Chung-Hoo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 827~832
One of the most important issues in AC PDP is luminance and luminous efficacy. To improve the luminance and luminous efficacy, new sustain electrode structure which contains long discharge gap is necessary. However, it causes a rise of firing voltage. In this experiment, a new structure is proposed in order to solve this problem. To drop the firing voltage, the hump shaped electrode is inserted into the forward area of the main discharge gap. The experimental results show that proposed structures with 160um discharge gap have high firing voltage by 38V, high luminance by 30% and high luminous efficacy by 15% compared with conventional type having 60um discharge gap. In addition, the proposed structure with hump electrode shows lower firing voltage by 24V compared with the test panel with 160um discharge gap which doesn't have hump electrode though they have similar luminous efficacy.
Dependence of Round Type Electrodeless Lamp According to Ferrite Core and Cold Spot Temperature
Kim, Nam-Goon ; Yang, Jong-Kyung ; Lee, Jong-Chan ; Han, Hoo-Sek ; Park, Jee-Sik ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 833~838
Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of elecrodeless lamp are related to ferrite core and cold spot temperature. Additionally, spectrum, color temperature and coordination are measured to check that is relation with ambient temperature.
The SOC, Capacity-fade, Resistance-fade Estimation Technique using Sliding Mode Observer for Hybrid Electric Vehicle Lithium Battery
Kim, Il-Song ; Lhee, Chin-Gook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 839~844
A novel state of health estimation method for hybrid electric vehicle lithium battery using sliding mode observer has been presented. A simple R-C circuit method has been used for the lithium battery modeling for the reduced calculation time and system resources due to the simple matrix operations. The modeling errors of simple model are compensated by the sliding mode observer. The design methodology for state of health estimation using dual sliding mode observer has been presented in step by step. The structure of the proposed system is simple and easy to implement, but it shows robust control property against modeling errors and temperature variations. The convergence of proposed observer system has been proved by the Lyapunov inequality equation and the performance of system has been verified by the sequence of urban dynamometer driving schedule test. The test results show the proposed observer system has superior tracking performance with reduced calculation time under the real driving environments.
Performance Enhancement of RMRAC Controller for Permanent Magnent Synchronous Motor using Disturbance compensator
Jin, Hong-Zhe ; Lim, Hoon ; Lee, Jang-Myung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 845~851
A simple RMRAC (Robust Model Reference Adaptive Control) scheme for the PMSM (Permanent Magnent Synchronous Motor) is proposed in the synchronous frame. A current control of PMSM is the most inner loop of electro-mechanical driving systems and it requires a fast and simple control law to play a foundation role in the control hierarchy. In the proposed synchronous current model, the input signal is composed of a calculated voltage by proposed adaptive laws and real system disturbance. The gains of feed-forward and feedback controllers are estimated by the proposed modified Gradient method respectively, where the system disturbances are assumed as filtered current tracking errors. After the estimation of the system disturbances from the tracking errors, the corresponding voltage is fed forward to control input voltage to compensate for the disturbances. The proposed method is robust against high frequency disturbance and has a fast dynamic response. It also shows a good real-time performance due to it's simplicity of control structure. Through the simulations and real experiments, efficiency of the proposed method is verified.
Adaptive Neural Control for Strict-feedback Nonlinear Systems without Backstepping
Park, Jang-Hyun ; Kim, Seong-Hwan ; Park, Young-Hwan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 852~857
A new adaptive neuro-control algorithm for a SISO strict-feedback nonlinear system is proposed. All the previous adaptive neural control algorithms for strict-feedback nonlinear systems are based on the backstepping scheme, which makes the control law and stability analysis very complicated. The main contribution of the proposed method is that it demonstrates that the state-feedback control of the strict-feedback system can be viewed as the output-feedback control problem of the system in the normal form. As a result, the proposed control algorithm is considerably simpler than the previous ones based on backstepping. Depending heavily on the universal approximation property of the neural network (NN), only one NN is employed to approximate the lumped uncertain system nonlinearity. The Lyapunov stability of the NN weights and filtered tracking error is guaranteed in the semi-global sense.
Capacitive Parameter Estimation of Passive Telemetry RF Sensor System Using RLS Algorithm
Kim, Kyung-Yup ; Lee, John-Tark ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 858~865
In this paper, Capacitive Telemetry RF Sensor System using Recursive Least Square (RLS) algorithm was proposed. General Telemetry RF Sensor System means that it should be "wireless", "implantable" and "batterless". Conventional Telemetry RF Sensor System adopts Integrated Circuit type, but there are many defects like complexity of structure and the limitation of large power consumption in some cases. In order to overcome these disadvantages, Telemetry RF Sensor System based on inductive coupling principle was proposed in this paper. Proposed Telemetry RF Sensor System is very simple because it consists of R, L and C and measures the changes of environment like pressure and humidity in the type of capacitive value. This system adopted RLS algorithm for estimation of this capacitive parameter. For the purpose of applying RLS algorithm, proposed system was mathematically modelled with phasor method and was quasi-linearized. As two parameters such as phase and amplitude of output voltage for estimation were needed, Phase Difference Detector and Amplitude Detector were proposed respectively which were implemented using TMS320C2812 made by Texas Instrument. Finally, It is verified that the capacitance of proposed telemetry RF Sensor System using RLS algorithm can be estimated efficiently under noisy environment.
Least Mean Square Estimator for Motor Frequency Measurement Based on Linear Hall Sensor
Choi, Ga-Hyoung ; Ra, Won-Sang ; Kwak, Ki-Seok ; Yoon, Tae-Sung ; Park, Jin-Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 866~874
Motor frequency can be measured by a hall sensor. Among the many hall sensors, a linear type hall sensor is good at high accuracy frequency measuring problem. However, in general, this linear type hall sensor has DC offset which can vary along sensor's operating voltage change. Therefore, In motor frequency measurement problem using the linear hall sensor, it needs an estimator that can estimate frequency and DC offset simultaneously. In this paper, we propose the least mean square estimator to estimate motor frequency. To verify its performance, we compare the LMS estimator with a commercial analog tachometer. Experimental results shows the proposed LMS estimator works well in varying frequency and stationary DC offset.
Determination of Optimal Checkpoint Interval for Real-time Control Tasks Considering Performance Index Function
Kwak, Seong-Woo ; Jung, Young-Joo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 875~880
In this paper, a novel method to determine the optimal checkpoint interval for real-time control task is proposed considering its performance degradation according to tasks's execution time. The control task in this paper has a specific sampling period shorter than its deadline. Control performance is degraded as the control task execution time is prolonged across the sampling period and eventually zero when reached to the deadline. A new performance index is defined to represent the performance variation due to the extension of task execution time accompanying rollback fault recovery. The procedure to find the optimal checkpoint interval is addressed and several simulation examples are presented.
Acoustic Sensors based Fault Diagnosis Algorithm for Large-scaled Power Machines using Neural Independent Component Analysis
Cho, Hyun-Cheol ; Lee, Jin-Woo ; Lee, Young-Jin ; Lee, Kwon-Soon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 881~888
We present a novel fault diagnosis methodology using acoustic sensor systems and neural independent component analysis for large-scaled power machines. Acoustic sensors are carried out to measure sounds generated from power machines whose signal is used to determine whether fault is occurred or not. Acoustic measurements are independently mixed and deteriorated from original source signals. We propose a demixing algorithm against such mixed signals by means of independent component analysis which is achieved based on information theory and higher-order statistics to derive learning mechanism.
Design of a Frequency Synthesizer for UHF RFID Reader Application
Kim, Kyung-Hwan ; Oh, Kun-Chang ; Park, Jong-Tae ; Yu, Chong-Gun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 889~895
In this paper a Fractional-N frequency synthesizer is designed for UHF RFID readers. It satisfies the ISO/IEC frequency band(
) and is also applicable to mobile RFID readers. A VCO is designed to operate at 1.8GHz band such that the LO pulling effect is minimized. The 900MHz differential I/Q LO signals are obtained by dividing the differential signal from an integrated 1.8GHz VCO. It is designed using a
RF CMOS process. The measured results show that the designed circuit has a phase noise of -103dBc/Hz at 100KHz offset and consumes 9mA from a 1.8V supply. The channel switching time of
over 5MHz transition have been achieved, and the chip size including PADs is
An Efficient Foot-Force Distribution Algorithm for Straight-Line Walking of Quadruped Robots with a Failed Leg
Yang, Jung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 896~901
This paper addresses the foot force distribution problem for quadruped robots with a failed leg. The quadruped robot has fault-tolerant straight-line gaits with one leg in locked-joint failure, and has discontinuous motion with respect to the robot body. The proposed method is operated in two folds. When the robot body stands still, we use the feature that there are always three supporting legs, and by incorporating the theory of zero-interaction force, we calculate the foot forces analytically without resort to any optimization technique. When the robot body moves, the conventional pseudo-inverse algorithm is applied to obtain the foot forces for supporting legs. Simulation results show the validity of the proposed scheme.
Development of a Characteristic Point Detection Algorithm for the Calculation of Pulse Wave Velocity
Lee, Lark-Beom ; Im, Jae-Joong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 5, 2008, Pages 902~907
Shape of the pulse waveform is affected by the visco-elasticity characteristics of the arterial wall and the reflection waves generated at the bifurcations of arterial branches. This study was designed to improve the accuracy for the extraction of pulse wave features, then proved the superiority of the developed algorithm by clinical evaluation. Upstroke point of the pulse wave was used as an extraction feature since it is minimally affected by the waveform variation. R-peak of the ECG was used as a reference to decide the minimum level, then intersection of the least squares of regression line was used as an upstroke point. Developed algorithm was compared with the existing minimum value detection algorithm and tangent-intersection algorithm using data obtained from 102 subjects. Developed algorithm showed the least standard deviation of
compared with that of the existing algorithms,
. Moreover, the rate of standard deviation of more than 1.00m/s for the PWV values reduced with the range of
, which proved the superiority of the newly developed algorithm.