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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 59, Issue 12 - Dec 2010
Volume 59, Issue 11 - Nov 2010
Volume 59, Issue 10 - Oct 2010
Volume 59, Issue 9 - Sep 2010
Volume 59, Issue 8 - Aug 2010
Volume 59, Issue 7 - Jul 2010
Volume 59, Issue 6 - Jun 2010
Volume 59, Issue 5 - May 2010
Volume 59, Issue 4 - Apr 2010
Volume 59, Issue 3 - Mar 2010
Volume 59, Issue 2 - Feb 2010
Volume 59, Issue 1 - Jan 2010
Selecting the target year
Interaction and Transient Analysis to FACTS Devices in Seoul Area
Yoon, Jong-Su ; Kim, Jae-Han ; Lee, Seong-Doo ; Choi, Jang-Hum ; Seo, Bo-Hyeok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1929~1935
This paper describes the operation effect of FACTS devices in the Korean power system. At the year of 2010, three FACTS devices is under commercial operation in the Seoul area. Among them, 345kV
STATCOM at Mi-Geum substation and 345kV
SVC at Dong-Seoul substation are very close at their electrical and geographical distance. Therefore, the additional analysis including interaction and mutual transient is necessary. Therefore, a detailed EMTDC/PSCAD simulation model was developed and steady-state/transient analysis was implemented.
Development of algorism to optimal operation of Power Generation considering Regional Regulation of CO
Kim, Yong-Ha ; Kim, Young-Gil ; Lee, Pyong-Ho ; Jo, Hyun-Mi ; Woo, Sung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1936~1941
This purpose of this paper is to propose a methodology for optimal generating operation in power system to minimize the cost of generation subject to not only system constraints but also regional
emission constraints. To solve this ELD problem calculated range limit on minimum and maximum power outputs by regional Equal Generator how each regional capacity is connected into one and expressed Equal Fuel Cost Function considering regional
emission constraints. Accordingly, being modified regional load, new power outputs considering regional
emission constraints were calculated by ELD. The proposed model for evaluating availability is tested on IEEE RTS(Reliability Test System)-24 in detail.
A Study on the Reliability Estimation of Loop Distribution System Considering Directional Relay
Park, Jin-Hyun ; Cho, Sung-Min ; Cho, Bo-Hyeon ; Sin, Hee-Sang ; Kim, Jae-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1942~1948
Recently, the radial distribution system is operating as one-way power flow. These are popular because of their simple design and relatively low cost. However, radial systems are sensitive to outages due to single contingencies. Also, reliability of supply is becoming increasingly important. Accordingly, an appearance of the loop distribution system is inevitable and the other countries such as Macau, Florida, Taiwan are actively working on. The reliability of distribution system is estimated with reliability indices. In this paper, comparing with the radial distribution system, we evaluate and analyse the reliability of loop distribution system quantitatively considering directional relay.
Transient Analysis and Evaluation of 345kV Combined Transmission Line Connected with GIL
Jang, Hwa-Youn ; Lee, Jong-Beom ; Kim, Yong-Kap ; Jung, Chae-Kyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1949~1955
This paper describes the characteristic and effectiveness of combined GIL transmission line through lightning surge analysis. In addition the XLPE cable is analyzed in the same condition to compare with GIL. Lighting surge analysis is carried out by EMTP/ATP-Draw to obtain overvoltage of GIL and XLPE cable at service-point and load-out area of underground line. Propagation velocity is calculated in combined transmission lines with GIL and XLPE cable. The overvoltage is also analyzed on GIL and XLPE cable with or without arrester operation. The Analysis results show that overvoltage of GIL is occurred higher than XLPE cable at the same condition. Therefore it is evaluated that the application of GIL at the field should be considered cautiously when more detailed transient analysis, another electrical testes and economic evaluations are implemented.
Relationship Analysis of Power Consumption Pattern and Environmental Factor for a Consumer's Short-term Demand Forecast
Ko, Jong-Min ; Song, Jae-Ju ; Kim, Young-Il ; Yang, Il-Kwon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1956~1963
Studies on the development of various energy management programs and real-time bidirectional information infrastructures have been actively conducted to promote the reduction of power demands and CO2 emissions effectively. In the conventional energy management programs, the demand response program that can transition or transfer the power use spontaneously for power prices and other signals has been largely used throughout the inside and outside of the country. For measuring the effect of such demand response program, it is necessary to exactly estimate short-term loads. In this study, the power consumption patterns in both individual and group consumers were analyzed to estimate the exact short-term loads, and the relationship between the actual power consumption and seasonal factors was also analyzed.
A Development of Demand Response Operation System and Real-Time Pricing based on Smart Grid
Ko, Jong-Min ; Song, Jae-Ju ; Kim, Young-Il ; Jung, Nam-Jun ; Kim, Sang-Keu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1964~1970
A new intelligent power network (Smart Grid) that grafts some new technologies, such as the extension of the new and reproducible energy, electric motors, and electric storages, onto the regulation of green house gases according to the recent convention on climate changes has been actively promoted. As establishing such an intelligent power network, it is possible to implement a real-time rate system according to the change from the conventional single directional information transmission to the bidirectional information transmission. Such a real-time rate system can provide power during the chip rate hour by avoiding the high rate hour although customers use the same level of power through providing such real-time rate information including power generation costs. In this study, the establishment of an operating system that makes an effective use of the real-time rate system and its operation method are to be proposed.
Continuation Time Integration (CTI)-Based Time Domain Simulation Analysis for Wind Farms
Cho, Sung-Koo ; Song, Hwa-Chang ; Lee, Jang-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1971~1979
As a result of increasing environmental concern, the penetration of renewable power on power systems is now increasing. Wind energy can be considered as the most economical energy sources to generate electricity without depletion of fossil fuel. To devise adequate control strategies for wind farm, time domain simulation analysis needs to be performed. This presents a continuation time integration (CTI)-based time domain simulation algorithm for wind farm with doubly fed asynchronous generator (DFAG) connected to the external power systems. This paper depicts how to time trajectories are traced using CTI-based time domain simulation. Also this paper describes the possibilities of hierachical control for wind farm output limitation, and the coordinated control has been designed by hierarchical control structured from central control level to wind farm control board and to an individual wind turbine level. Finally it shows an illustrative example of time domain simulation result with two test systems through case study.
Radiation Characteristics of Parallel Slot Antenna for Automotive Radar System
Kim, Byeong-Woo ; Hur, Jin ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1980~1985
This paper is about design of optimal structure of slot antenna array antenna with inner waveguide in accordance with the slot model, and fabrication of its prototype sample operating at the frequency of 24 GHz. Results of this work can be employed as a useful tool to develop and diversify slot antenna having superior performance and omni-directivity to that of current antenna. The implemented antenna demonstrates ultra-wideband performance for frequency ranges 24 GHz with the relatively high and flat antenna gain of 18.64dBi and low sidelobe levels. In addition, a
antenna array for phased-array systems and mm-wave sensor applications is also presented.
Analysis of Two-phase E-core Switched Reluctance Machines Using Magnetic Equivalent Circuit Technique
Lee, Chee-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1986~1989
The modification of magnetic structures for an E-core switched reluctance machine (SRM) comprising two segmented stator cores or a monolithic stator core is presented for ease of assembly, good manufacturability, mechanical robustness, and electromagnetic performance improvement. The E-core stator has four small poles with phase windings and two or four large poles (hereafter referred to as common poles), in between. The common poles are shared by both phases for positive torque generation during the entire operation. The E-core SRMs are compared to a conventional two-phase SRM. The comparison includes cost savings, torque, copper and core losses, and efficiency in order to validate the distinct features of the E-core SRMs. Magnetic equivalent circuit (MEC) technique is employed for proving the benefits of the E-core common-pole structure.
Analysis of Radial Force on a Permanent Magnet Synchronous Motor Caused by Dimensional Variation
Lee, Chee-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1990~1995
Main reasons for causing vibration in a permanent magnet synchronous motor (PMSM) are torque ripple and radial force harmonics, and hence, both of them are undesirable in high-precision machine tools and accurate motion-control actuators. Recent research on radial force is the prediction of major vibration frequencies and modes in terms of motor design such as different winding types and a fractional slot number per pole in the stator. Also, proper phase current has been investigated for minimizing radial force harmonics. During the previous studies, all the motors are assumed to be ideally built up in terms of mechanical dimensions, but it is impossible due to dimensional variation within or outside tolerance in production. Therefore, in this paper, the effect of several key factors on radial force is examined and compared regarding manufacturing imperfection.
Output AC Voltage Control of a Three-Phase Z-Source Inverter by the Voltage Gain and Modulation Index Control
Kim, Se-Jin ; Jung, Young-Gook ; Lim, Young-Cheol ; Yang, Seung-Hak ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 1996~2005
This paper proposes a new method for constant control of the output AC voltage of a voltage-fed three phase Z-source inverter (ZSI), in case of Z-network DC voltage variation or heavy change of load. The modulation index for the reference output AC voltage of ZSI can be calculated by the basic definition of ZSI, the input DC voltage and capacitor voltage of Z-network. And, the output AC voltage of ZSI is controlled by the modified space vector modulation (SVM) with the calculated modulation index. By the proposed method, the modulation index of output AC voltage is closely following in the reference modulation index. The validity of the proposed method is verified using PSIM simulation. In case which the input DC voltage of ZSI is heavily changed from 100[V] to 70[V] (or to 150[V]) and in case which load is changed from
, we confirmed that the output AC voltage of ZSI is constantly controlled by the proposed method because the modulation index of ZSI is also simultaneously changed. Finally, FFT and %THD of the output voltage and current of ZSI by the proposed method are analyzed.
Temperature Control of Superheater Steam in Thermal Power Plant
Shin, Hwi-Beom ; Lee, Soon-Young ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2006~2011
The superheater in the thermal power plant makes the wet steam into the dry steam with high temperature and high pressure by using the boiler heat. The dry steam pressure rotates the turbine-generator system. The efficiency and life time of the boiler heavily depends on the steam temperature regulation. The steam temperature can be deviated from the reference by the MW demand of the power plant. It is therefore required that the PI(proportional-integral) controller should be robust against the disturbance such as the MW demand. In this paper, the PI controller with the integral state predictor is proposed and applied to regulate the steam temperature of the superheater, and it is compared with the conventional PI controller operated in the thermal power plant in view of control performance.
Modeling and Parameter Estimation of Superheater and Desuperheater
Lee, Soon-Young ; Shin, Hwi-Beom ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2012~2015
In this paper, the mathematical models of the superheater and the desuperheater are derived based on the fundamental laws of physics, mass and energy balance. The parameters of the models are developed for the 500[MW] thermal power plant using the actual data. The simulated model outputs are well matched with the actual ones. It is expected that the proposed models are useful for the temperature controller design of the thermal power plant.
Effects of Nitrogen Additive Gas on the Property of Active Layer and the Device Characteristic in Indium-zinc-oxide thin Film Transistors
Lee, Sang-Hyuk ; Bang, Jung-Hwan ; Kim, Won ; Uhm, Hyun-Seok ; Park, Jin-Seok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2016~2020
Indium-zinc-oxide (IZO) films were deposited at room temperature via RF sputtering with varying the flow rate of additive nitrogen gas (
). Thin film transistors (TFTs) with an inverted staggered configuration were fabricated by employing the various IZO films, such as
-added and pure (i.e., w/o
-added), as active channel layers. For all the deposited IZO films, effects of additive
gas on their deposition rates, electrical resistivities, optical transmittances and bandgaps, and chemical structures were extensively investigated. Transfer characteristics of the IZO-based TFTs were measured and characterized in terms of the flow rate of additive
gas. The experimental results indicated that the transistor action occurred when the
flow rate of 0.4-1.0 sccm) IZO films were used as the active layer, in contrast to the case of using the pure IZO film.
Piezoelectric Properties of lead free (Na
Ceramics with ZnO Addition
Lee, Dong-Hyun ; Lee, Seung-Hwan ; Nam, Sun-Pill ; Lee, Young-Hie ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2021~2025
Electrical and structural properties were investigated on the effects of ZnO and the lead-free NKN-LST ceramics with the addition of ZnO were fabricated by a conventional mixed oxide method. A gradual change in the crystal and microstructure was observed with the increase of ZnO addition. For the NKN-LST-ZnO ceramics sintered at
, bulk density increased with the addition of ZnO and showed maximum value at addition 2.0mol% of ZnO. Curie temperature of the NKN-LST-ZnO ceramics slightly decreased with adding ZnO. The dielectric constant, piezoelectric constant (
) and electromechanical coupling factor (
) increased at the small amount of ZnO addition, which might be due to the increase in density. The high piezoelectric properties = 153 pC/N, electromechanical coupling factor = 0.484 and dielectric constant = 2883 were obtained for the NKN-LST+0.5ZnO ceramics sintered at
Electric Conduction Properties of NaCl Electrolyte as a Function of Electrode Materials
Kim, Yong-Hyuk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2026~2031
The electrical characteristics of galvanic cell which is composed of the cathode electrode(graphite, carbon and copper) and the anode electrode(Zn and Mg) were investigated. For this research as electrolyte 2~12 wt% NaCl aqueous solution were used. At graphite cathode electrodes which use Zn and Mg with the anode electrode, the open circuit voltage was 1.3V most highly. The maximum output power increased as the electrolyte concentration increased, due to a increase in ion density. When Zn and Mg with the anode electrode, the maximum output power respectively was evaluated as 2.2mW and 5.5mW about the graphite cathode electrode in the NaCl 4wt%. The research results indicated that the output power of cell which is composed with graphite with the cathode and Mg with the anode was most excellent and the efficiency of the cell could be enhanced by increasing the electrolyte concentration.
A Design of Dual Band Amplifier Using Left Handed Transmission Lines
Lim, Jong-Sik ; Lee, Jae-Hoon ; Lee, Jun ; Koo, Ja-Kyung ; Jeong, Yong-Chae ; Han, Sang-Min ; Ahn, Dal ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2032~2037
This paper describes a design of dual band amplifier using left handed (LHJ) transmission line, which is a part of composite right/left handed (CRLH) transmission line. It is well known that CRLH transmission lines show dual band frequency response. At first, two single-band amplifiers for frequency f1 and f2 are designed, and their matching networks at both amplifiers are synthesized into the dual band matching network by adopting CRLH structure. As an example for proving the validity of the proposed design, a dual band amplifier operating at 1800MHz and 2300MHz is designed, fabricated and measured. The simulation and measurement show that the proposed amplifier operates well at the desired dual bands with the gain of 13.65dB and 19dB at 1850MHz and 2360MHz, respectively, and a good matching performances. In addition, a quite good agreement between the simulation and measurement is observed.
Analysis of LED Package Properties by PCB Material and Via-hole Construction
Lee, Se-Il ; Yang, Jong-Kyung ; Kim, Sung-Hyun ; Lee, Seung-Min ; Park, Dae-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2038~2042
In this paper, we confirmed the thermal & optical properties for improving the heat transfer coefficient by changing the via hole size and in FR4 PCB with the same area. Osram 1W power LED Package (Golden Dragon) was used and the K-factor which is relative constant between LED junction temperature and forward bias was measured with power source meter(KEITHLEY 2430) to measure the thermal resistance from PCB configuration. As results, thermal resistance in metal PCB came out to the lowest as
and thermal resistance in FR4 PCB without via-holes emerged as the highest as
. However thermal resistance of FR4 PCB could have decreased until
in 0.6 mm by using the via hole. Also, the luminous flux could have improved, too.
A Study on Realization and Receiving Characteristic Analysis of Visible Light Wireless Communication System for Power Line Communications Using ATmega16 Microcontroller
Yun, Ji-Hun ; Hong, Geun-Bin ; Kim, Yong-Kab ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2043~2047
This study is to solve problems of depletion of RF bandwidth frequency, confusion possibility, security that current wireless communications system have and is to confirm possibility of applying next generation network. To solve problems of current wireless communications system, visible light communications system for power line communications using ATmega16 Microcontroller is was realized and receiver property was analyzed. PLC exclusive chip APLC-485MA, Microcontroller ATmega16, 5pi bulb type LED and high flux LED, visible light receiving sensor LLS08-A1 were used for transmitter and receiver. Performance was analyzed by designed program and an oscilloscope. It was showed average 20% improved receiver rate rather than bulb type LED in the case of high flux LED through voltage change rate on communication distance and LED type of distance between 10 to 50 cm. The blue LED showed the best performance among measured LED types with above 10% of voltage decreasing rate. But As it gradually becomes more distant, the precise date was difficult to obtain due to weak light. To overcome these sort of problems, specific values such as changing conditions and efficiency value relevant to light emitting parts and visible light receiving sensor should be calculated and continuous study and improvements should also be accomplished for the better communications condition.
Pedestrian Navigation System using Inertial Sensors and Vision
Park, Sang-Kyeong ; Suh, Young-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2048~2057
Is this paper, a pedestrian inertial navigation system with vision is proposed. The navigation system using inertial sensors has problems that it is difficult to determine the initial position and the position error increases over time. To solve these problems, a vision system in addition to an inertial navigation system is used, where a camera is attached to a pedestrian. Landmarks are installed to known positions so that the position and orientation of a camera can be computed once a camera views the landmark. Using this position information, estimation errors in the inertial navigation system is compensated.
Estimation of the Sensor Location and the Step for Personal Navigation System
Kim, Tae-Un ; Lee, Ho-Won ; Chwa, Dong-Kyoung ; Hong, Suk-Kyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2058~2065
This paper presents the sensor location and step estimation algorithm for personal navigation system (PNS). PNS has the disadvantage in that the position of the sensor must be fixed on a human body. Three-axis acceleration sensor is used to solve the disadvantage and to consider the real situation. We simplify the measurement data by using the band pass filter, witch It has the advantage in the detection of characteristic point. Through the detected characteristic points, it is possible to setup the parameter for the pattern detection. Depending on the sensor location, the parameters have the different type of noise covariance. Particularly, when the position of the sensor is changed, the impulse noise shows up. Considering the noise, we apply the recursive least square algorithm using the variable forgetting factors, which can classify the sensor location based on the estimated parameters. We performed the experiment for the verification of the proposed algorithm in the various environments. Through the experimental results, the effectiveness of the proposed method is verified.
A Dynamic Output Feedback Variable Structure Controller for Uncertain Systems with Unmatched System Matrix Uncertainty
Lee, Jung-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2066~2072
In this paper, a variable structure dynamic output feedback controller with an transformed sliding surface is designed for the improved robust control of a uncertain system under unmatched system uncertainty, matched input matrix uncertainty, and disturbance satisfying some conditions. This paper is extended from the results of the static output feedback VSS in . To effectively remove the reaching phase problems, an initial condition of the dynamic output is determined. The previous some limitations on the dynamic output feedback variable structure controller is overcome in this systematic design. A stabilizing control is designed to generate the sliding mode on the predetermined sliding surface S=0 and as a results the closed loop exponential stability is obtained and proved together with the existence condition of the sliding mode on S=0 for all unmatched system matrix uncertainties. To show the usefulness of the algorithm, a design example and computer simulations are presented.
Stabilization Control of line of sight of OTM(On-The-Move) Antenna
Kang, Min-Sig ; Cho, Yong-Wan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2073~2082
The 4-th generation of mobile communication aims to realize global, fast and mobile communication service. The satellite communication charges a key role in this field. In this study, an OTM(On-The-Move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite was addressed. Since vehicles move during communication, active antenna line-of-sight stabilization is a core technology to guarantee high satellite communication quality. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. Various disturbance torques such as static and dynamic mass imbalance torques, variation of moment of inertia according to elevation angle, friction torque related to vehicle motion, equivalent disturbance torque due to antenna roll motion, etc. were analyzed. As a robust stabilization control, rate feedback with sliding mode control and position feedback with proportional+integral control was suggested. To compensate antenna roll motion, a supplementary roll rate feed forward control was included beside of the feedback control loop. The feasibility of the analysis and the proposed control design were verified along with some simulation results.
Analysis on the Surge Characteristics of the Solenoid Valve for Anti-Lock Brake System
Kim, Byeong-Woo ; Park, Hoo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2083~2088
It is necessary to carry out quantitative analysis for the ABS hydraulic modulator to upgrade the system performances. Mathematical modeling method for the ABS hydraulic modulator, is suggested in the view of electromagnetism and fluid mechanics. Also, an analytic method is proposed for the resultant forces of electromagnetism and hydraulic pressure generated in the real vehicle ABS. The relationships between the design factor of Inlet & outlet solenoid valve and the system performance of ABS, are investigated through the analytical precess.
A Study on PCB's Latch-up Phenomenon by External Electrical Surge
Ji, Yeong-Hwa ; Jo, Sung-Han ; Jung, Chang-Gyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2089~2092
There are many cases that interrupt the production process because of malfunctions caused by electronic circuit boards which control equipment, but it is difficult to distinctly identify the causes in many cases. Especially, CMOS devices with the control logic circuit return automatically to normal state after their own faults. Therefore it is not easy to analyze the problems with electronic circuit boards. Recently, nuclear power plant experienced a failure due to the malfunction of electronic circuit boards and it was identified that the reason of the malfunction was because of latch-up phenomenon caused by external surge in electronic devices. This paper presents the causes and the phenomenon of latch-up by experiment and also a way using counter EMF diodes, noise filters and surge protective devices to prevent latch-up phenomenon from electronic circuit boards, finally confirms the effectiveness of the result by experiment.
Development of a fixer attaching robot system
Park, Sang-Sin ; Sung, Young-Whee ; Kim, Dong-Hyeon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2093~2102
In this paper, we introduce a fixer attaching robot system which is used to attach several fixers to a TV cabinet. It is necessary to automate the fixer attaching process for two reasons. One is that the process is very harmful because very strong ultraviolet rays are used in that process. The other is that the productivity and the overall quality of the end-product are determined by the fixer attaching process. We proposed 9 candidates for the robot system to be used in the fixer attaching process. Then we simulated cycle time for each of the 9 candidates with considering physical constraints. We also considered other aspects such as the easiness of implementation, possible interference with other mechanical structure, and cost etc. to choose one of the 9 candidates. We implemented the chosen robot system and adopted it in a TV manufacturing process.
A Recognition System for Multiple Mobile Robots Using RFID System in Smart Space
Tak, Myung-Hwan ; Yeom, Dong-Hae ; Cho, Young-Jo ; Joo, Young-Hoon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2103~2107
This paper deals with the recognition of multiple mobile robots equipped with RFID tag. In the case that the number of robots recognized by each RFID reader is larger than that of allocated slots, the clashing recognition occurs. And, in the case that the total number of robots recognized by all RFID reader is larger than that of real robots, the repetitious recognition occurs. We employ the dynamic frame slot allocation by using the ALOHA algorithm to prevent the clashing recognition and estimate the number of robots by using the received signal strength indication to prevent the repetitious recognition. The numerical experiment shows the reliability and the efficiency of the proposed method.
Design of a Channel Estimator for the LTE System Based on the Multirate Signal Processing
Yoo, Kyung-Yul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2108~2113
The Long Term Evolution (LTE) system is based on the Orthogonal Frequency Division Multiplexing (OFDM) and relies its channel estimation on the lattice-type pilot samples in the multipath fading channel environment. The estimation of the channel frequency response (CFR) makes use of the least squares estimate (LSE) for each pilot samples, followed by an interpolation both in time- and in frequency-domain to fill up the channel estimates for subcarriers corresponding to data samples. Any interpolation scheme could be adopted for this purpose. Depending on the requirements of the target system, we may choose a simple linear interpolation or a sophisticated one. For any choice of an interpolation scheme, these is a trade-off between estimation accuracy and numerical cost. For those wireless communication systems based on the OFDM and the preamble-type pilot structure, the DFT-based channel estimation and its variants have been successfully. Yet, it may not be suitable for the lattice-type pilot structure, since the pilot samples are not sufficient to provide an accurate estimate and it is known to be sensitive to the location as well as the length of the time-domain window. In this paper, we propose a simple interpolated based on the upsampling mechanism in the multirate signal processing. The proposed method provides an excellent alternative to the DFT-based methods in terms of numerical cost and accuracy. The performance of the proposed technique is verified on a multipath environment suggested on a 3GPP LTE specification.
Analysis of Angular Velocity during Toe Tapping for the Quantification of the Lower Limb Bradykinesia in Patients with Idiopathic Parkinson's Disease
Kim, Ji-Won ; Kwon, Yu-Ri ; Eom, Gwang-Moon ; Kim, Hyung-Sik ; Yi, Jeong-Han ; Kwon, Do-Young ; Koh, Seong-Beom ; Park, Byung Kyu ; Kwon, Tae-Kyu ;
The Transactions of The Korean Institute of Electrical Engineers, volume 59, issue 11, 2010, Pages 2114~2118
The purpose of this study was to analyze bradykinesia of toe tapping movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. 39 PD patients (age:
yrs, H&Y stage:
), 14 eldelry subjects with comparable mean age (
yrs) and 17 healthy young subjects (
yrs) participated in this study. Angular velocity during repetitive toe tapping movement was measured in both feet using a gyro sensor system. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity signal. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.02). All measures were significantly correlated with UPDRS scores(r=-0.689~-0.825). These results suggest that the developed system can be used as quantitative measures of the lower limb bradykinesia in PD patients.