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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 58, Issue 12 - Dec 2009
Volume 58, Issue 11 - Nov 2009
Volume 58, Issue 10 - Oct 2009
Volume 58, Issue 9 - Sep 2009
Volume 58, Issue 8 - Aug 2009
Volume 58, Issue 7 - Jul 2009
Volume 58, Issue 6 - Jun 2009
Volume 58, Issue 5 - May 2009
Volume 58, Issue 4 - Apr 2009
Volume 58, Issue 3 - Mar 2009
Volume 58, Issue 2 - Feb 2009
Volume 58, Issue 1 - Jan 2009
Selecting the target year
A Study on a Shielding Effect of the Messenger Wires in Distribution Lines
Kim, In-Soo ; Han, Woong ; Yeo, Sang-Min ; Kim, Chul-Hwan ; Weon, Bong-Ju ; Lim, Yong-Hun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 431~436
As the telecommunication lines bring into widespread use, one of the most important aspects related to power distribution systems is effectively to evaluate the effect on the telecommunication lines from power lines. One of the efficient methods to evaluate the effect is to measure the induced voltage of a telecommunication line as a result of a ground-loop. If the power lines cause high induced voltage, the ground reference in the telecommunication lines is no longer a stable potential, so signals may ride on the noise. A ground loop is common wiring conditions where a ground current may take more than one path to return to the grounding electrode at the arrangement between the power lines and telecommunication lines. When a multi-path connection between the power lines and telecommunication line circuits exists, the resulting arrangement is known as a ground loop. Whenever a ground loop exists, there are potential for damages or abnormal operations of the telecommunication lines. The power lines can induce the voltage on the communication line. The effects can be calculated by considering the inductances and capacitances. However, if we assume that there are only power lines, it doesn't have a practical meaning because there are conductors with other purpose in the neighborhood of the lines. If we consider that case, we need more complex system. Therefore we suggest more complex system considering the conductors with other purpose in the neighborhood of the lines. The neutral wires and the overhead ground wires are considered for calculating the induced voltage. We assume that there are the messenger wires beside the power line as a result of increased use of them. The main purpose of this paper is a study on a shielding effect of messenger wires in the distribution lines. EMTP(Electro-Magnetic Transients Program) program is used for the induced voltage calculation.
A Study on The Available Transfer Capability(ATC) with Transient Stability Constraints
Kim, Yang-Il ; Jeong, Sung-Won ; Gim, Jae-Hyeon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 437~443
In recent years, electric power systems have been experiencing a rapid change due to the increasing electricity market. For the effective use of power system under the deregulated environment, it is important to make a fast and accurate calculation of the maximum available transfer capability (ATC) from a supply point to a demand point. In this paper, the purpose of this research is to calculate ATC fast and accurately for securing the stability of system and raising the efficiency as a result of anticipating transmission congestion according to transmission open access progressed in the future under the regulated environment of electricity market. In this paper, a study utilized a relation of the potential energy and energy function by which calculated CCT and then utilized a relation of PEBS for transient stability ATC calculation. In this paper, ATC was calculated as RPF and Energy Function method and calculation results of each method was compared. Contingence ranking method decided the weak bus by the Eigenvalues of Jacobian matrix and overloading branches by PI-index. As a result, a study proved the fast and accurate ATC calculation method considering transient stability suggested in this paper. Through the case study using New England 39 bus system, it is confirmed that the proposed method can be used for real time operation and the planning of electric market.
A Method to Monitor the Reliability of In-house Power Supply Systems in Nuclear Power Plants Based on Probabilistic Assessment
Park, Jin-Yeub ; Jerng, Dong-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 444~449
This paper introduces a method to establish performance criteria of the in-house power supply system in nuclear power plants. The performance criteria of the system is presented in terms of the number of function failures and amount of the out-of-service time that can be allowed commensurate with the probabilistic safety assessment results of the nuclear power plants. To obtain the performance criteria such as reliability and availability, the functions of the system were analyzed and probabilistic assessment results were utilized. This method provides quantitative guidelines in selecting and monitoring system functions to determine an adequate level of maintenance quality in order to ensure the probabilistic goals for the safety of the nuclear power plants.
An Analysis of Superconducting Fault Current Limiter Operation According to Asymmetry Fault Current
Rhee, Sang-Bong ; Kim, Chul-Hwan ; Kim, Kyu-Ho ; Kim, Jae-Chul ; Hyun, Ok-Bae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 450~454
This paper analyzes a asymmetry current with SFCL (Superconducting Fault Current Limiter) operation during transient period, when a fault occurs in power systems. The principle of asymmetry current nature is reviewed and asymmetry components reduction with SFCL operation is explained. To verify the performance of SFCL, a EMTP/ATPDraw model of SFCLs using MODELS language developed and simulated. Throughout the simulation, results presents the main factors for reducing the asymmetry component of fault current are not a quenching time, but a limiting resistance of SFCL and fault initiated angle.
Bid-based Direct Load Control Framework Under Electricity Markets
Lee, Ho-Chul ; Song, Sung-Hwan ; Yoon, Yong-Tae ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 455~461
This paper proposes Direct Load Control(DLC) operation scheme using a bidding system and the methodology to value proper quantity decided by the DLC program, which is a kind of resources for stabilization of electricity market price during peak times by managing consumer electricity demand. Since DLC program in Korea is based on the contract with the customers participating in this program, it is difficult to anticipate voluntary participation. That is, incentive for participants in DLC program is insufficient. To cope with this point, it is necessary to develop a new market mechanism and market compatible operation scheme for DLC programs. DLC market mechanism is deemed to be equipped with iterative bidding system, independent operation from energy market, and interactive with bidding information on energy market. With this market mechanism, it is important to find the optimal operation point of DLC allowing for the factors of stabilizing the electricity market price and compensating DLC implementation. This paper focuses on the mathematical approaches for the bid-based DLC operation scheme and examines several scenarios for the following technical justifications: 1) stabilization of electricity market price during peak times, 2) elasticity of demand.
A Study on the Power Expansion Planning Model using Multi-criteria Decision Making Rule
Han, Seok-Man ; Kim, Bal-Ho H. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 462~466
The power expansion planning is large and capital intensive capacity planning. In the past, the expansion planning was established with the proper supply reliability in order to minimize social cost. However, the planning can't use cost minimizing objective function in the power markets with many market participants. This paper proposed the power expansion planning model using multi-criteria decision rule. This model used multi objective function considering not only cost minimizing but also GENCO's intension. This paper compared proposed model with WASP model in order to verify the result of proposed model.
A Study of the Long-term Fuel Mix with the Introduction of Renewable Portfolio Standard
Lee, Jeong-In ; Han, Seok-Man ; Kim, Bal-Ho H. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 467~477
Renewable Portfolio Standard (RPS) is a regulatory policy that requires the generation companies to increase the proportion of renewable energy sources such as wind, solar, LFG, fuel cell, and small hydro. Recently, Korean government decided to increase the portion of renewable energy to 3% to total electricity generation by 2012 from the current level of 0.13%. To achieve this goal, an innovative plan for market competitiveness would be required in addition to the present Feed-In-Tariff (FIT). That is Korean government has taken it into consideration to introduce a Renewable Portfolio Standard (RPS) as an alternative to FIT. This paper reviews the impact of RPS on the long-term fuel mix in 2020. The studies have been carried out with the GATE-PRO (Generation And Transmission Expansion PROgram) program, a mixed-integer non-linear program developed by Hongik university and Korea Energy Economics Institute. Detailed studies on long-term fuel mix in Korea have been carried out with four RPS scenarios of 3%, 5%, 10% and 20%. The important findings and comments on the results are given to provide an insight on future regulatory policies.
Assessment of Power Retail Cost by Penetration scenarios of Decentralized Generation in Korean Power System
Kim, Yong-Ha ; Woo, Sung-Min ; Oh, Seok-Hyun ; You, Jeong-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 478~485
This paper describes retail cost through scenario in the ratio of CG(Centralized Generation) and DG(Decentralized Generation) that constructs new generation capacity in the future. it is not calculated for the supply, but for demand considering an advantage of DG. In the Korea Power System, retail cost that composed of construction, T&D, fuel, maintenance and environment shows macro-trend that power system planning through penetration for DG will be more significant.
A Study on Probabilistic Reliability Evaluation of Power System Considering Solar Cell Generators
Park, Jeong-Je ; Liang, Wu ; Choi, Jae-Seok ; Cha, Jun-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 486~495
This paper proposes a new methodology on reliability evaluation of a power system including solar cell generators (SCG). The SCGs using renewable energy resource such as solar radiation(SR) should be modeled as multi-state operational model because the uncertainty of the resource supply may occur an effect as same as the forced outage of generator in viewpoint of adequacy reliability of system. While a two-state model is well suited for modeling conventional generators, a multi-state model is needed to model the SCGs due to the random variation of solar radiation. This makes the method of calculating reliability evaluation indices of the SCG different from the conventional generator. After identifying the typical pattern of the SR probability distribution function(pdf) from SR actual data, this paper describes modelling, methodology and details process for reliability evaluation of the solar cell generators integrated with power system. Two test results indicate the viability of the proposed method.
Study on the Characteristic of Ld, LQ Parameter for Interior Permanent Magnet Synchronous Motor in different barrier width
Jang, Ik-Sang ; Kim, Seung-Joo ; Jin, Chang-Sung ; Kim, Ki-Chan ; Lee, Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 496~501
Interior Permanent Magnet Synchronous Motor (IPMSM) produces two kind of torque that Magnetic and Reluctance torque. The permanent magnet linkage flux
and d-axis and q-axis inductances have an important influence on the torque characteristic of IPMSM. Thus their accurate prediction is essential for predicting performance aspect such as the torque and flux-weakening capabilities. In this paper, the influence of barrier width on the
is calculated by FEM analysis. Predictions are validated by comparison the average torques, using Maxwell Stress Tensor method.
Critical Current Estimation of HTS Magnets by using Field Dependent E-J Relation
Kang, Myung-Hun ; Koo, Myung-Hwan ; Lee, Hee-Joon ; Cha, Guee-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 502~508
The method to determine the operating current of HTS magnets needs to be different from that of LTS magnets. This paper presented estimation of the critical current of pancake windings. The pancake windings can be excited by a single power source or by multiple power sources. Critical currents were determined by using field dependent E-J relation. For the better estimation of the critical current, a new method to define the magnetic field of the HTS wire has been proposed. Calculated critical currents of pancake windings were compared with measured ones of the HTS BSCCO magnet consisting of 10 pancake windings. According to the test results, the estimated critical currents of pancake windings agreed well with that of measured ones. Effects of the single and multiple power source excitation on the critical currents have been also examined.
Analysis of the Magnetic Noise for Large Power Induction Motors at Loading Operation
Hong, Gil-Dong ; Chun, Tae-Won ; Lee, Hong-Hee ; Kim, Heung-Gun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 509~515
When a squirrel cage induction motor is loaded, the magnetic noise can increase depending on the load current. It is due to the variation of air gap harmonic fluxes from the rotor current induced by loading. This unfavorable noise can be anticipated by analysing the radial force waves in the air gap, the mode shapes of them, and stator core natural frequencies at each mode. With the experimental tests with the different rotor slot numbers, the variation of magnetic noise depending on the load current is studied and the method to reduce the magnetic noise is suggested with the newly developed magnetic noise analysis program.
The realization of the Dimmable Magnetic Ballast for HID Lamps by the Life Time Extension Method of the Relays
Jung, Kwang-Hyun ; Lee, Hyeon-Jin ; Park, Chong-Yeon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 516~522
The dimmable magnetic ballast which applies the variable inductor needs a switching process for the dimming process, and it consists of mechanical relays because of costs and reliabilities. However, it is hard to operate with correct timing in mechanical relay, so relays reduce their own life time in inductive applications. Moreover this creates a destructive problem at the switching process. The life time reduction of relays means the life time reduction of the ballast. Thus, in this paper, we described the problem at the witching process in the dimmable magnetic ballast with a variable inductor, which consists of relays and the soft AC switching method in order to solve the problems. As result, we achieved the improvement of the life time and reliability of the ballast.
Simulink-based Modelling and Simulation for a Single-phase UPFC
Kang, Moon-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 523~530
This paper presents a study on a small scale single-phase UPFC preliminary researches on power quality compensating schemes of electrical railway. As the UPFC is very complicated power-electronic system consisting of grid-connected transformers, four single phase inverters interconnected with dc-link capacitors and various electrical apparatuses, multiple controllers and control algorithms are needed, and entire UPFC has been modelled in the form of block diagrams and simulated by using Simulink. The main purpose of the compensating system is to manage reactive and active powers with the four single phase inverters, so, the control effort has been focused on the power flow control and has been realized through the hysteresis current control of the single phase inverters. And transport-delayed PLL with additional delay-time compensating term has been used to synchronize a grid voltage and the simulation results have shown that the compensating term could improve PLL performance under some frequency variation of the voltage.
Operation Scheme to Regulate the Active Power Output and to Improve the Forecasting of Output Range in Wind Turbine and Fuel-Cell Hybrid System
Kim, Yun-Seong ; Moon, Dae-Seong ; Won, Dong-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 531~538
The paper deals with an operation scheme to improve the forecasting of output range and to regulate the active power output of the hybrid system consisting of a doubly fed induction generator (DFIG) and a fuel-cell. The power output of the wind turbine fluctuates as the wind speed varies and the slip power between the rotor circuit and power converter varies as the rotor speed change. The power fluctuation of a DFIG makes its operation difficult when a DFIG is connected to grid. A fuel cell system can be individually operated and adjusted output power, hence the wind turbine and fuel cell hybrid system can overcome power fluctuation by using a fuel-cell power control. In this paper, a fuel-cell is performed to regulate the active power output in comparison with the regulated active power output of a DFIG. And it also improves the forecasting of output range. Based on PSCAD/EMTDC tools, a DFIG and a proton exchange membrane fuel cell(PEMFC) is simulated and the dynamics of the output power in hybrid system are investigated.
Sensitivity Enhancement in Measurement of Hydrogen Gas Dissolved in Oil using Gas Collection Time
Heo, Jong-Cheol ; Sun, Jong-Ho ; Kang, Dong-Sik ; Jeong, Joo-Young ; Park, Jung-Hoo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 539~543
This paper describes the sensitivity enhancement in measurement of the hydrogen gas dissolved in oil using gas collection time. On-line gas measurement is a useful for continuous monitoring of power transformer. Recently many studies on hydrogen gas measurement, due to their simplicity and low price, have been done for transformer monitoring. In measurement of the hydrogen gas in oil, the suitable sensitivity and resolution in the desired ranges of the gas concentrations are needed for the reliable monitoring of power transformers. In this study, the sensor output trends were analyzed with the hydrogen gas collection time which means the time to collect the hydrogen gas before reaction of hydrogen gas sensor. It is indicated that the sensor outputs were increased with the increase of hydrogen gas collection times at the same hydrogen gas concentrations.
Microstructure and Properties of SBN Thin film with Deposition Temperature
Kim, Jin-Sa ; Choi, Woon-Shik ; Kim, Chung-Hyeok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 544~547
(SBN) thin films are deposited on Pt-coated electrode(Pt/Ti/
/Si) using RF sputtering method at various deposition temperature. The optimum conditions of RF power and Ar/
ratio were 60[W] and 70/30, respectively. Deposition rate of SBN thin films was about 4.17[nm/min]. The crystallinity of SBN thin films were increased with increase of deposition temperature in the temperature range of
, the surface rougness showed about 4.33[nm]. The capacitance of SBN thin films were increased with the increase of deposition temperature.
Electric Field Optimization using the NURB curve in a Gas-Insulated Switchgear
Han, In-Su ; Kim, Eung-Sik ; Min, Suk-Won ; Lee, June-Ho ; Park, Jong-Keun ; Lee, Tae-Hyung ; Park, Choon-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 548~558
This paper attempts to develop an algorithm which optimizes the electric field through the so-called NURB(Non-Uniform Rational B-spline) curve in order to improve the insulation capacity. In particular, the NURB curve is a kind of interpolation curve that can be expressed by a few variables. The electric field of a conductor is computed by Charge Simulation Method(CSM) while that of a spacer by Surface Charge Method(SCM); this mixed calculation method is adopted for the electric field optimization. For calculation of the initial and optimal shapes, the Gauss-Newton method, which is quite easy to formulate and has slightly faster convergence rate than other optimization techniques, was used. The tangential electric field, the total electric field, and the product of the tangential electric field and area (Area Effect) were chosen as the optimization objective function by the average value of electric field for the determined initial shape.
A Study on Sterilization Characteristics of Elliptical Reactor by Using Xenon Flashlamp and Photocatalyst
Lee, Dong-Gil ; Hong, Ji-Tae ; Choi, Kyoung-Hwa ; Cha, Jae-Ho ; Kim, Hong-Ju ; Kim, Hee-Je ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 559~565
In this paper, we invented a new and unique technique for the sterilization of Escherichia coli(E. coli) in polluted water. We applied a rich ultra-violet(UV) light from pulsed xenon flashlamp and photocatalyst(TiO2) to sterilize E. coli in polluted water. This method based on the use of UV light and photocatalyst is eco-friendly and does not cause secondary pollution. The proposed elliptical reactor is able to concentrate on quartz sleeve coated TiO2 or general quartz sleeve. The primary objective of our research was to determine the important parameters such as pulse repetition rate and input voltage and to know on the sterilizing efficiency of quartz sleeve coated TiO2 and general quartz sleeve. We obtained to achieve 99.999% sterilization in as little as 6 pulses at 800V in case of quartz sleeve coated Ti02, and 10 pulses at 800V in case of general quartz sleeve for 5 minutes. Although transmitted light of quartz sleeve coated TiO2 is deceased, the sterilizing efficiency is increased by 40% than general quartz sleeve. The reason of high sterilizing efficiency is that generated hydroxyl radical(OH) by photocatalyst and is able to concentrate light at a focus by using elliptical reactor.
The Verification of Breakage Possibility and Vibration Properties of Glass Insulators by the High-speed Railway Service
Kim, Young-Seok ; Shong, Kil-Mok ; Jung, Jin-Su ; Jeon, Yong-Joo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 566~572
This paper has studied breakage possibility of glass insulators by resonance and accelerated deterioration through the comparison of the natural vibration and on site vibration. The natural frequencies of the strut tube glass insulator was measured within a range of less than 1kHz. In the on site vibration, the largest frequency that was imposed on strut tube glass insulators was 80Hz with 1.13g of vertical vibration in the viaduct section, the largest vertical vibration (0.38g) was detected at 103Hz in the open route section. When site vibration and natural vibration of strut tube glass insulators were compared in terms of characteristics, the resonance frequency was not the same. In both the viaduct and open route sections, it seems that the impact by vertical vibration in strut tube glass insulators is large. It's very unlikely that glass insulators were damaged by fatigue accumulation of vibration since the possibility of damage by resonance was very low in consideration of the characteristics of natural vibration and site vibration of glass insulators. In addition, no damage was detected in the accelerated deterioration test.
Synthesized analysis and its verification of the piezoresistive pressure sensor
Yi, Seung-Hwan ; Lee, Gon-Jae ; Han, Seung-Oh ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 573~577
Piezoresistive pressure sensor have become the successfully-commercialized MEMS product and the related technologies have been well developed over the past decades. Regarding the design methodology, however, the coupled-physics FEM analyses of the transducer itself and the signal-processing circuitry design based on the conventional EDA are separated and both of the analyses were sequentially processed for the full design of the pressure sensor. For the fast and effective R&D, new design methodology is proposed in this paper where the FEM results are linked to the EDA environment and therefore most of the design works can be done in the EDA environments, which means the time-consuming FEM analyses can be minimized. In order to verify the proposed approach, a typical piezoresistive pressure sensor having the silicon diaphragm and piezoresistors was modeled and analyzed based on the proposed methodology. The verification results showed that the simulated results were matched well with the measured data within the 7% difference while the simulation time was reduced less than 5% compared to the conventional methodology. Through the proposed approach, various types of the piezoresistive pressure sensors can be developed in more effective way.
Design of Electromagnetically Driven Micro Scanning Mirror for Laser Animation System
Lee, Kyoung-Gun ; Jang, Yun-Ho ; Yoo, Byung-Wook ; Jin, Joo-Young ; Lim, Yong-Geun ; Kim, Yong-Kweon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 578~585
In this paper, we present the design of an electromagnetic scanning mirror with torsional springs. The scanning mirror consisting of torsional springs and electromagnetic coils was designed for the applications of laser animation systems. We analyzed and optimized three types of torsional springs, namely, straight beam springs (SBS), classic serpentine springs (CSS), and rotated serpentine springs (RSS). The torsional springs were analyzed in terms of electrical resistance, fabrication error tolerance, and resonance mode separation of each type using analytical formula or numerical analysis. The RSS has advantages over the others as follows: 1) A low resistance of conductors, 2) wide resonance mode separation, 3) strong fabrication error tolerance, 4) a small footprint. The double-layer coils were chosen instead of single-layer coils with respect to electromagnetic forces. It resulted in lower power consumption. The geometry of the scanning mirror was optimized by calculations; RSS turn was 12 and the width of double-layer coil was
, respectively. When the static rotational angle is 5 degrees, the power consumption of the mirror plate was calculated to be 9.35 mW since the resistance of the coil part and a current is
and 8.75 mA, respectively. The power consumption of full device including the mirror plate and torsional springs was calculated to be 9.63 mW.
Effect of Various
Type Metal Electrode in the AC PDP
Yoo, Su-Bok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 586~590
Recently, an AC Plasma Display Panels(PDP) with the metal sustain electrodes have been reported in order to reduce the manufacturing cost of the AC PDP. However, the luminance and efficacy of the AC PDP with metal electrodes are worse than those of the AC PDP with ITO electrodes. In this paper, various
type metal electrodes are suggested, in order to improve the electro-optical characteristics of the AC PDP with metal electrodes. Among the suggested electrode types, luminance of Hump electrode structure is higher by
and discharge current of Asymmetry electrode structure is lower by 5% than those of Pi electrode structure, respectively. Moreover,
of Hump electrode structure is reduced to 10% as compared with Pi electrode structure in address period for ADS driving scheme. In all aspects, the characteristics of Hump and Asymmetry electrode structure show best performance.
Corrective Control of Input/Output Asynchronous Sequential Machines for Overcoming Disturbance Inputs
Yang, Jung-Min ; Kwak, Seong-Woo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 591~597
The problem of controlling a finite-state asynchronous sequential machine is examined. The considered machine is governed by input/output control, where access to the state of the machine is not available. In particular, disturbance inputs can infiltrate into the asynchronous machine and provoke unauthorized state transitions. The control objective is to use output feedback to compensate the machine so that the closed-loop system drive the faulty asynchronous machine from a failed state to the original one. Necessary and sufficient condition for the existence of appropriate controllers are presented in a theoretical framework. As a case study, the closed-loop system of an asynchronous machine with the proposed control scheme is implemented in VHDL code.
Performance Analysis of an Anisotropic Magnetoresistive Sensor-Based Vehicle Detector
Kang, Moon-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 598~604
This paper proposes a vehicle detector with an anisotropic magnetoresistive (AMR) sensor and addresses experimental results to show the detector's performance. The detector consists of an AMR sensor and mechanical and electronic apparatuses. The AMR sensor, composed of four magnetoresistors, senses disturbance of the earth's magnetic field caused by a vehicle moving over the sensor and then produces an output indicative of the moving vehicle. This paper verifies performance of the detector on the basis of experimental results obtained from the field tests carried under the two traffic conditions on local highways in Korea. First, I show the vehicle counting performance on a low speed congested highway by comparing the vehicle counts measured by the detector with the exact counts. Second, both vehicle counts and average speeds calculated from the measured point-occupancy on another continuously free running highway are compared with the reference values obtained from a loop detector which has two independent loop coils, where I have used several performance indices including mean absolute percentage error (MAPE) to show the performance consistency between the two types of detectors.
A Study on the Rotation Angle Estimation of HMD for the Tele-operated Vision System
Ro, Young-Shick ; Yoon, Seung-Jun ; Kang, Hee-Jun ; Suh, Young-Soo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 605~613
In this paper, we studied for the real-time azimuthal measurement of HMD (Head Mounted Display) to control the tele-operated vision system on the mobile robot. In the preexistence tele-operated vision system, a joystick was used to control the pan-tilt unit of the remote camera system. To give the sense of presence to the tele-operator, we used a HMD to display the remote scene, measured the rotation angle of the HMD on a real time basis, and transmitted the measured rotation angles to the mobile robot controller to synchronize the pan-tilt angles of remote camera with the HMD. In this paper, we suggest an algorithm for the real-time estimation of the HMD rotation angles using feature points extraction from pc-camera image. The simple experiment is conducted to demonstrate the feasibility.
Optimal Force Distribution for Quadruped Walking Robots with a Failed Leg
Yang, Jung-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 614~620
The force distribution in multi-legged robots is a constrained, optimization problem. The solution to the problem is the set points of the leg contact forces for a particular system task. In this paper, an efficient and general formulation of the force distribution problem is developed using linear programming. The considered walking robot is a quadruped robot with a locked-joint failure, i.e., a joint of the failed leg is locked at a known place. For overcoming the drawback of marginal stability in fault-tolerant gaits, we define safety margin on friction constraints as the objective function to be maximized. Dynamic features of locked-joint failure are represented by equality and inequality constraints of linear programming. Unlike the former study, our result can be applied to various forms of walking such as crab and turning gaits. Simulation results show the validity of the proposed scheme.
The Multiple Branch Predictor Using Perceptrons
Lee, Jong-Bok ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 621~626
This paper presents a multiple branch predictor using perceptrons. The key idea is to apply neural networks to the multiple branch predictor. We describe our design and evaluate it with the SPEC 2000 integer benchmarks. Our predictor achieves increased accuracy than the Bi-Mode and the YAGS multiple branch predictor with the same hardware cost.
A Novel Current Steering Cell Matrix DAC Architecture with Reduced Decoder Area
Jeong, Sang-Hun ; Shin, Hong-Gyu ; Cho, Seong-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 627~631
This paper presents a novel current steering cell matrix DAC(digital-to-analog converter) architecture to reduce decoder area. The current cell matrix of a existing architecture is selected by columns and lows thermometer code decoder of input bits. But The current cell matrix of a proposal architecture is divided 2n by the thermometer code decoder of upper input bits and are selected by the thermometer code decoder of middle and lower input bits. Because of this configuration, decoder numbers have increased. But the gate number that composed of decoder has decreased. In case of the designed 8 bit current steering cell matrix DAC, the gate number of decoder has decreased by about 55% in comparison with a existing architecture.
Reputation Analysis of Document Using Probabilistic Latent Semantic Analysis Based on Weighting Distinctions
Cho, Shi-Won ; Lee, Dong-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 632~638
Probabilistic Latent Semantic Analysis has many applications in information retrieval and filtering, natural language processing, machine learning from text, and in related areas. In this paper, we propose an algorithm using weighted Probabilistic Latent Semantic Analysis Model to find the contextual phrases and opinions from documents. The traditional keyword search is unable to find the semantic relations of phrases, Overcoming these obstacles requires the development of techniques for automatically classifying semantic relations of phrases. Through experiments, we show that the proposed algorithm works well to discover semantic relations of phrases and presents the semantic relations of phrases to the vector-space model. The proposed algorithm is able to perform a variety of analyses, including such as document classification, online reputation, and collaborative recommendation.
Development of a Modified CFS Method in Forward-Link AOA Positioning
Im, Hyun-Ja ; Park, Ji-Won ; Song, Seung-Hun ; Sung, Tae-Kyung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 639~644
This paper presents a modified CFS (Closed-Form Solution) for FLAOA (Forward Link AOA) measurements. During when the pseudo-measurement equation for FLAOA is derived, the angle measurement noise is treated more carefully in approximation. As the covariance matrix of the pseudo-measurement noise is influenced by unknown user positions and azimuth, a two-step estimation technique is used in the proposed CFS. The performance of the proposed CFS for FLAOA is compared to that of the conventional CFS for FLAOA and RLAOA (Reverse Link AOA) in a computer simulation. Simulation results show that the proposed method is potentially suitable for applications involving the localization and guidance of indoor mobile robots.
Development of Ambulatory Speech Audiometric System
Shin, Seung-Won ; Kim, Kyeong-Seop ; Lee, Sang-Min ; Im, Won-Jin ; Lee, Jeong-Whan ; Kim, Dong-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 58, issue 3, 2009, Pages 645~654
In this study, we present an efficient ambulatory speech audiometric system to detect one's hearing problems at an earlier stage as possible without his or her visit to the audiometric testing facility such in a hospital or a clinic. To estimate a person's hearing threshold level in terms of speech sound response in his or her local environment, a digital assistant(PDA) device is used to generate the speech sound with implementing audiometric Graphic User Interface(GUI) system. Furthermore, a supra-aural earphone is used to measure a subject's hearing threshold level in terms of speech sound by the compensating the transducer's gain by adopting speech sound calibration system.