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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of The Korean Institute of Electrical Engineers
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The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 56, Issue 12 - Dec 2007
Volume 56, Issue 11 - Nov 2007
Volume 56, Issue 10 - Oct 2007
Volume 56, Issue 9 - Sep 2007
Volume 56, Issue 8 - Aug 2007
Volume 56, Issue 7 - Jul 2007
Volume 56, Issue 6 - Jun 2007
Volume 56, Issue 5 - May 2007
Volume 56, Issue 4 - Apr 2007
Volume 56, Issue 3 - Mar 2007
Volume 56, Issue 2 - Feb 2007
Volume 56, Issue 1 - Jan 2007
Selecting the target year
A Study on the Improved Efficiency of Distribution Network Reliability Using DAS
Hwang, Woo-Hyun ; Bae, Sung-Hwan ; Kim, Ja-Hee ; Kim, Jae-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2059~2064
This paper analyzed distribution network reliability related with the increment of outages and duration time according to distribution facilities increasing. KEPCO introduced distribution automation system in 1998 which could recognize outage section by remotely monitoring the fault current and reduce the blackout area by remotely controlling distribution switches. As the result of this outage time reduction using distribution automation system, the minimum distribution automation rate was fined out in this paper on the base of analyzing diverse data and how many switches were used in distribution system to improve distribution network reliability at the situation of distribution facilities increasing. This result can be used as the model that an overseas utility company applies distribution automation system in the future.
The Effects of Harmonic Current in the Operating Characteristics of High Temperature Superconducting Cable
Lee, Geun-Joon ; Lee, Jong-Bae ; Hwang, Si-Dole ; Sohn, Song-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2065~2071
This paper suggests the harmonic effects on HTS(High Temperature Superconducting) power cable. HTS cable is regarded as not only one of the important countermeasure to supply high density power demand area, but also one of countermeasures greenhouse technology. However, with the development of digital society, the distribution line power is much contaminated with harmonics generated by various power electronic equipments. This paper describes how the HTS cable responds to the harmonic and increases AC losses caused by hysteresis phenomenon. EMTDC based harmonic simulation results are compared with AC loss measured values.
Implementation of Frequency Relaying Algorithm based on Multi-Agent System using EMTP-MODELS
Lee, Byung-Hyun ; Kim, Chul-Hwan ; Yeo, Sang-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2072~2077
The primary objective of all power systems is to maintain the reliability and to minimize outage time for fault or the others. The frequency relaying algorithm perceives a variation of system frequency and thereafter detects the unbalance between generation and load. A multi-agent system is composed of multiple interacting computing elements that are known as agents. In this paper, frequency relaying algorithm is designed by multi-agent system and is implemented by EMTP-MODELS. To verify performance of the frequency relaying algorithm based on multi-agent system, simulations by EMTP have been carried out.
Characteristics of Transformer-Type SFCL according to the Connecting Methods of Secondary Coils
Cho, Yong-Sun ; Park, Hyoung-Min ; Chung, Soo-Bok ; Choi, Hyo-Sang ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2078~2083
We have analyzed operating characteristics of transformer-type superconducting fault current limiter (SFCL) according to the serial or parallel connections of secondary coils with
(YBCO) thin films. The turn ratio between the primary and secondary coils was 63:21. Transformer-type SFCL using a transformer with secondary winding of serial or parallel coils could reduce the unbalanced quench caused by differences of the critical current density between YBCO thin films. We found that transformer-type SFCL having serial or parallel connections induced simultaneous quench between the superconducting units. The limiting current in the transformer-type SFCL with a parallel connection was lowered to 30 % compared to the SFCL with a serial connection. In the meantime, when the currents generated in the superconducting units were similar, the voltage value in the parallel connection was 60 % as low as that in the serial connection. However, the voltage generated in the primary winding was some higher. In conclusion, we found that transformer-type SFCL with parallel connection of secondary coils was more effective in fault current limiting characteristics and in the reduction of the consumption power for superconducting units compared to those of the transformer-type SFCL with serial connection of secondary coils.
Intelligent Diagnosis System for DGA Using Fuzzy Pattern Classification and Neural Network
Cho, Sung-Min ; Kweon, Dong-Jin ; Nam, Chang-Hyun ; Kim, Jae-Chul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2084~2090
The DGA (Dissolved Gases Analysis) technique has been widely using for fault diagnosis of the power transformers. Some electric power utility company establishes the criteria of DGA to improve reliability, because of difference of operation environment and design of power transformer. In this paper, we introduce intelligent diagnosis system for DGA result of KEPCO (Korea Electric Power Cooperation). This system can classify patterns type of gases ratio that frequently occurs in recent result of gases analysis using Fuzzy Inference. The classification of Patterns let us know that major causes of gases generation based on type of patterns. Finally, Neural Network based on patterns diagnose transformer. NN was trained using result data of DGA of actually faulted transformers recently. Result of intelligent diagnosis system is right well in comparison with actual inner inspection of transformers.
Verification of Underground Distribution Line Modeling with Field Test
Yun, Chang-Sub ; Lee, Jae-Bong ; Kim, Byong-Suk ; Lee, Jong-Beom ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2091~2097
This paper described the verification of modeling technique of underground distribution from comparison between field test and simulation. It needs more exact transient phenomenon analysis model to establish lightning protection of underground distribution line. Although, there were a lot of transient phenomenon researches, nobody could has verified the confidence of modeling from field tests in interior until now. So, simulation model verified field test is needed to analyse transient phenomenon of underground distribution system. The examination must be accomplished in many different condition before suggesting these verified analysis model. In this paper, the conditions were examined and the various data results on the different line composition was compared with the EMTP simulation, when the lightning impulse test was accomplished at underground distribution line. Also the value between field test and simulation was very closed and the method of modeling has demonstrated confidence, when the method is used to analyse domestic transient phenomenon of underground distribution.
A Study on Modeling Methods for Cable Covering Protective Unit on Underground Power Cable Systems
Choi, Kyung-Kyu ; Jang, Tae-In ; Yoon, Hyung-Hee ; Jung, Chae-Kyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2098~2102
The conventional CCPU(Cable Covering Protective Unit) modeling methods which are used by Type 99 and Type 92 in EMTP simulation are firstly discussed in this paper, and then some problems of them are also investigated. Modeling method using Type 99 causes unstable characteristic at initial transient of CCPU operation. Time delay has also effect on the output of CCPU modeling. So, in this paper, a new modeling method for CCPU is designed by DBM(Data Base Module) of EMTP. The characteristic of Type 92 is used for the new modeling method. The reliability of this one is proved by comparing simulation with measured data. Specially, at initial transient, the waveform of the new method shows more stable result than that of conventional method using Type 99. Also, the peak value is similar to measured data.
The On-line Observer System Characteristics Analysis of Synchronous Reluctance Motor Using a Coupled FEM & Preisach Model
Kim, Hong-Seok ; Lee, Jung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2103~2108
This study investigates the dynamic characteristics of Synchronous Reluctance Motor (SynRM), with segmental rotor structure, using finite element method in which the moving mesh technique is considered. The focus of this paper is the efficiency of on-line parameter identification system for position sensorless control of a SynRM considering saturation and iron loss. Comparisons are given with angle of the observer and those of proposed FEM & Preisach model of synchronous reluctance motor, respectively. The position sensorless control using identified motor parameters is realized, and the efficiency of the on-line parameter identification system is verified by experimental results.
Optimal Design of Permanent Magnet Wind Generator for Maximum Annual Energy Production
Jung, Ho-Chang ; Jung, Sang-Yong ; Hahn, Sung-Chin ; Lee, Cheol-Gyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2109~2115
The wind generators have been installed with high output power to increase the energy production and efficiency. Hence, Optimal design of the direct-driven PM wind generator, coupled with F.E.M(Finite Element Method) and Genetic Algorithm(GA), has been performed to maximize the Annual Energy Production(AEP) over the whole wind speed characterized by the statistical model of wind speed distribution. Particularly, the parallel computing via internet web service has been applied to loose excessive computing times for optimization. The results of the optimal design of Surface-Mounted Permanent Magnet Synchronous Generator(SPMSG) are compared with each other candidates to verify the usefulness of the maximizing AEP model.
D-Q Flux Linkage Identification for Interior Buried Permanent Magnet Synchronous Motor considering Cross-Magnetization
Kim, Min-Seok ; Kwak, Sang-Yeop ; Jung, Hyun-Kyo ; Jung, Sang-Yong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2116~2121
Numerical identification of synthetic d-q flux linkage, representative parameters for analyzing interior buried PM synchronous Motor(IPMSM) with distinguished magnetic saturation, has been peformed. Particularly, numerical identification of synthetic flux linkage using modified Finite Element Method(F.E.M) has been taken cross-magnetization of multi-layered PM configuration into consideration. Futhermore, experimental identification on the purpose-built prototype has been made to verify the validity of the numerically identified synthetic d-q flux linkages.
Study on the Measurement of Radiation Energy of the Arc in GCBs
Song, Ki-Dong ; Oh, Yeon-Ho ; Chong, Jin-Kyo ; Cho, Young-Sung ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2122~2126
A special PM-Tube(Photo Multiplier Tube) that is using the photoelectric effect has been designed and manufactured to measure the radiation energy of arc in a gas circuit breaker(GCB). The PM-Tube, LLG(liquid light guides), ND(neutral density) filter, and a model gas circuit breaker have been combined for the reception and the transmission of the light and a simplified synthetic test facility with the arc energy measuring system has been established. In the case of
and arc length 20mm, the radiation energy increases with the arc current but it tend to be saturated in the above 20kA. Under the arc current 20kA, the total radiation energy has the biggest value around 8kA and was not exceeded 40% of the total arc energy.
Simulation Model of 7 Phase BLDC Motor Drives with Phase Angle Control
Kim, Hyun-Cheol ; Oh, Hyung-Sik ; Kim, Jang-Mok ; Kim, Cheul-U ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2127~2134
The simulation model has been already developed not for 7 phase but for 3 phase BLDC motor. It is necessary to develop a new simulation model of multi-phase BLDC motor including the phase delay angle especially in the high speed region. In this paper, the suitability of the proposed model is verified through the several computer simulations, and experimented results.
Extraction of Design Parameters through Electromagnetic and Dynamic Analysis of Slotless Double-side PMLSM system
Jang, Won-Bum ; Lee, Sung-Ho ; Jang, Seok-Myeong ; You, Dae-Joon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2135~2144
This paper presents system design of the slotless double-side Permanent Magnet Linear Synchronous Machine system (PMLSM) through magnetic field analysis and dynamic modeling. In our analysis, 2-D analytical treatments based on the magnetic vector potential were adopted to predict magnetic field with space harmonics by PM mover magnetization and stator winding current. From these, the design parameters such as inductance, Back-emf, and thrust are estimated. And, the electrical dynamic modeling including synchronous speed is completed by calculation of a DC link voltage in effort to obtain the accurate mechanical power from Space Vector Pulse Width Modulation(SVPWM). Therefore, the system design of PMLSM is performed from estimation of design parameters according to PM size and coil turns in magnetic field and from calculation of a DC link voltage to satisfy base speed and base thrust represented as the maximum output power in dynamic modeling. The estimated values from the analysis are verified by the finite element method and experimental results.
Rotor & Stator Design on Torque Ripple Reduction for a Synchronous Reluctance Motor with Concentrated Winding using Response Surface Methodology
Choi, Yun-Chul ; Lee, Jung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2145~2149
This paper deals with optimum design criteria to minimize the torque ripple of a concentrated winding Synchronous Reluctance Motor (SynRM) using Response Surface Methodology (RSM). The feasibility of using RSM with the finite element method (FEM) in practical engineering problem is investigated with computational examples and comparison between the fitted response and the results obtained from an analytical solution according to the design variables of stator and rotor in concentrated winding SynRM (6slot).
A Power Supply System for Lighting of Aerodromes by Using Power Factor Correction and Constant Current Regulator
Shon, Jin-Geun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2150~2156
According as level of industry develops day after day, electricity load system of industry requires high level control, effectiveness and high efficiency. Among supply and control unit of suitable power supply in these load characteristic, inverter systems of constant current regulate is used widely control of lighting and electric heating system. But, problems that power factor deterioration and fast response of control, efficiency, harmonics and etc are still remain. Therefore, in this paper proposed an inverter systems with constant current regulation and power factor correction (PFC) circuit for lighting and beaconing of aerodromes. The effectiveness of the proposed system confirmed through experimental results of 10[kW] power supply system.
A Study on High Efficiency Electronic Ballast for Metal Halide Discharge Lamps
Kim, Hae-Jun ; Won, Jae-Sun ; Park, Jae-Wook ; Seo, Cheol-Sik ; Lee, Seung-Hee ; Sim, Kwang-Yeal ; Kim, Jong-Hae ; Kim, Dong-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2157~2165
A novel design technology for a high frequency electronic ballast for metal-halide discharge lamps is proposed. A PFC technique is adopted to get unit power factor and output frequency alteration technique is adopted to avoid acoustic resonance. For characteristics evaluation, the designed electronic ballast is presented using normalized parameter. To reduce losses of the ballast. ZVS control technique is adopted and the maximum flux density of magnetic core for inductor should be kept lower. The electronic ballast for 250[W] metal-halide discharge lamp is implemented and 96[%] efficiency and low conducted EMI level are accomplished.
Dielectric Properties and a Equivalent Circuit of ZnO-Based Varistor
Rho, Il-Soo ; Kang, Dae-Ha ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2166~2172
In this study a low-signal equivalent circuit based on the Double Schottky Barrier model is proposed for ZnO-based varistor. Since pin-lead inductance and stray capacitance are considered in pin-lead type ZnO varistor these inductance and capacitance could be removed from the experimental dielectric data of the varistor. According to the equivalent circuit simulation results the higher the varistor-voltage of varistor sample the capacitance of dielectric layer is larger, and the capacitances of semiconducting layer and depletion layer are smaller, while the parallel resistances of semiconducting layer and depletion layer are more larger values. Spectra of the dielectric loss factor
show 2 peaks in low frequency and high frequency regions respectively. The low-frequency peak is due to the relaxation by deep donors and the high-frequency peak is due to the relaxation by shallow donors. Above results are well consistent with the theoretical mechanism of ZnO varistor.
Analysis of Time-Dependent Behavior of Plasma Sheath using Ion Fluid Model
Lee, Ho-Jun ; Lee, Hae-June ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2173~2178
Dynamics of plasma sheath was analyzed using simple ion fluid model with poison equation. Incident ion current, energy, potential distribution and space charge density profile were calculated as a function of time. The effects of initial floating sheath on the evolution of biased sheath were compared with ideal matrix sheath. The effects of finite rising time of pulse bias voltage on the ion current and energy was studied. The influence of surface charging on the evolution of sheath was also investigated
A Study on the Sputtering System Using Ion Plating Technique
Jeong, Yeon-Ho ; Choi, Young-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2179~2183
In this paper, to produce sheet plasma with high density for ion plating, we designed magnetic circuit of ion plating device consisting of solenoid coil and rectangular permanent magnet. And, we analyzed the effects of the magnetic field distribution using FEM (Finite Element Methode). Additionally, we made a sputtering system including ion plating technique on the basis of the design and verified the possibility of the sheet plasma application for advanced sputter system.
Partial Discharge Location Method using Group Velocity Difference of Modes in a Electromagnetic Partial Discharge Signal in Gas Insulated Bus
Goo, Sun-Geun ; Ju, Hyoung-Jun ; Park, Ki-Jun ; Han, Ki-Seon ; Yoon, Jin-Yul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2184~2188
We developed a novel method of partial discharge(PD) location based on the fact that the waveform of PD signal propagate along the GIB (Gas Insulated Bus) is composed of several modes of electromagnetic wave with different group velocities and cut-off frequencies. From the PD waveform, measured at a broadband PD sensor attached on the GIB, we could derive arrival time and frequency components of different modes using the short term Fourier transform or etc. After the group velocities of different modes are calculated, the location of the PD source could be estimated. To show the effectiveness of this new locating method in a real on site application, we used this method to locate the position of a PD source at a 76 m long 345 kV GIB substation. The estimated location of the PD source using the method proposed above was in good agreement with the actual location found from the inspection result of internal component in the GIB with 2.4% of the estimation error.
Selective Reset Waveform using Wide Square Erase Pulse in an ac PDP
Jeong, Dong-Cheol ; Whang, Ki-Woong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2189~2195
In this paper, we propose a newly developed selective reset waveform of a ac PDP using the wide erase pulse technique with the control of address bias voltage. Although it is generally understood that the wide pulse erasing methode shows the narrow driving margin in an opposite discharge type ac PDP, we could obtain a moderate driving margin in a 3-electrode surface discharge type ac PDP. The obtained driving margin shows a strong dependency on the sustain voltage and the address bias voltage. The lower the sustain and the address bias voltage, the wider the driving margin. The pulse width of the proposed waveform is only
, which gives additional time to the sustain period, hence increases the brightness. The brightness and contrast ratio increase about 20% together comparing to the conventional ramp type selective reset waveform with the driving scheme of 10 subfield ADS method. The driving margin was measured with the line by line addressed pattern on the white test panel of 2inch diagonal size and the discharge gas was Ne+Xe4%, 400torr.
Measurement of Complex Permittivity and Permeability for Powder-type Materials
Park, Sang-Bok ; Lee, Jang-Soo ; Chong, Young-Seek ; Cheon, Chang-Yul ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2196~2201
Materials used at microwave are usually used as a dielectric with a manufacturing purpose of printed circuit boards, etc. Complex permittivity of them can be measured from attenuation constant or propagation constant of a transmission line using a microstrip line with bulk type. But as the technique recently which can manufacture to have complex permittivity and permeability demanded using nonferrous metals for powder-type grows up, we need sensors and methods which can measure characteristics of powder-type materials. So far measuring methods of permittivity and permeability with waveguide or coaxial cable are used but they have faults which have a complex measurement method and are difficult to simultaneously measure permittivity and permeability. In this paper, a simultaneous measuring method of permittivity and permeability with 2-port coaxial cable and a new proposed calculation. The proposed 2-port coaxial cable is designed to be easy to insert materials and to have a wideband. We measure permittivity and permeability of magnetic powder(Ni-Fe-Mo, Ni-Fe) which reveal its characteristic at
to identify the proposed sensor.
A Study on Thermal Conductivity Measurement and Optical Characteristics of Thin Films
Gwon, Hyuk-Rok ; Lee, Seong-Hyuk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2202~2207
The present article investigates experimentally and theoretically thermal and optical characteristics of thin film structures through measurement of thermal conductivity of Pyrex 7740 and reflectance in silicon thin film. The
method is used to measure thermal conductivity of very thin film with high accuracy and the optical characteristics in thin films are studied to examine the influence of incidence angle of light on reflectance by using the CTM(Characteristics Transmission Method) and the 633 nm He-Ne laser reflectance measurement system. It is found that the estimated reflectance of silicon show good agreement with experimental data. In particular, the present study solves the EPRT(Equation of Phonon Radiative Transport) which is based on Boltzmann transport equation for predicting thermal conductivity of nanoscale film structures. From the results, the measured thermal conductivity is in good agreement with the previous published data. Moreover, thermal conductivities are estimated for different film thickness. It indicates that as film thickness decreases, thermal conductivity decreases substantially due to internal scattering.
Research about Hyperspectral Imaging System for Pre-Clinical testing of Small Animal
Lee, kyeong-Hee ; Choi, Young-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2208~2213
In this study we have developed a hyperspectrum imaging system for highly sensitive and effective imaging analysis. An optical setup was designed using acoustic optical tunable filter (AOTF) for high sensitive hyperspectrum imaging. Light emitted by mercury lamp gets split in to diffracted and undiffracted beams while passing though AOTF. GFP transfected HEK-293 cell line was used as a model for in vitro imaging analysis. Cells were first, analyzed by fluorescence microscope followed by flow cytometric analysis. Flow cytometric analysis showed 66.31% transfection yield in GFP transfected HEK-293 cells. Various images of GFP transfected HEK-293 cell were grabbed by collecting the diffracted light using a CCD over a dynamic range of frequency of 129-171 MHz with an interval of 3 MHz. Subsequently, for in vivo image analysis of GFP transfected cells in mouse, a whole-body-imaging system was constructed. The blue light of 488 nm wavelength was obtained from a Xenon arc lamp using an appropriate filter and transmitted through an optical cable to a ring illuminator. To check the efficacy of the newly developed whole-body-imaging system, a comparative imaging analysis was performed on a normal mouse in presence and absence of Xenon arc irradiation. The developed hyperspectrum imaging analysis with AOTF showed the highest intensity of green fluorescent protein at 153 MHz of frequency and 494 nm of wavelength. However, the fluorescence intensity remained same as that of the background below 138 MHz (475 nm) and above 162 MHz (532 nm). The mouse images captured using the constructed whole-body-imaging system appeared monochromatic in absence of Xenon arc irradiation and blue when irradiated with Xenon arc lamp. Nevertheless, in either case mouse images appeared clearly.
Polarization-Controlled Waveband Switching in a Multiwavelength Fiber Bragg Grating Laser
Lee, Yong-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2214~2216
Based on a semiconductor optical amplifier and sampled fiber Bragg gratings, polarization-controlled waveband switching in multiwavelength fiber laser is successfully demonstrated at room temperature by using high polarization selectivity of a polarization beam splitter. A multiwavelength-switching operation between eight and six laser lines with signal to noise ratio over 35 dB and wavelength spacing of
has been successfully demonstrated. The switching displacement of the proposed laser was
. The intensity unevenness between different laser lines was measured to be less than 6.5 dB. The switching displacement between wavebands (groups of contiguous wavelengths), wavelength channels, and their spacings can be flexibly designed by the selected comb filters.
Wafer Level Package Using Glass Cap and Wafer with Groove-Shaped Via
Lee, Joo-Ho ; Park, Hae-Seok ; Shin, Jea-Sik ; Kwon, Jong-Oh ; Shin, Kwang-Jae ; Song, In-Sang ; Lee, Sang-Hun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2217~2220
In this paper, we propose a new wafer level package (WLP) for the RF MEMS applications. The Film Bulk Acoustic Resonator (FBAR) are fabricated and hermetically packaged in a new wafer level packaging process. With the use of Au-Sn eutectic bonding method, we bonded glass cap and FBAR device wafer which has groove-shaped via formed in the backside. The device wafer includes a electrical bonding pad and groove-shaped via for connecting to the external bonding pad on the device wafer backside and a peripheral pad placed around the perimeter of the device for bonding the glass wafer and device wafer. The glass cap prevents the device from being exposed and ensures excellent mechanical and environmental protection. The frequency characteristics show that the change of bandwidth and frequency shift before and after bonding is less than 0.5 MHz. Two packaged devices, Tx and Rx filters, are attached to a printed circuit board, wire bonded, and encapsulated in plastic to form the duplexer. We have designed and built a low-cost, high performance, duplexer based on the FBARs and presented the results of performance and reliability test.
Fabrication of Hollow-type Silicon Microneedle Array Using Microfabrication Technology
Kim, Seung-Kook ; Chang, Jong-Hyeon ; Kim, Byoung-Min ; Yang, Sang-Sik ; Hwang, In-Sik ; Pak, Jung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2221~2225
Hollow-type microneedle array can be used for painless, continuous and stable drug delivery through a human skin. The needles must be sharp and have sufficient length in order to penetrate the epidermis. An array of hollow-type silicon microneedles was fabricated by using deep reactive ion etching and HNA wet etching with two oxide masks. Isotropic etching was used to create tapered tips of the needles, and anisotropic etching of Bosch process was used to make the extended length and holes of microneedles. The microneedles were formed by three steps of isotropic, anisotropic, and isotropic etching in order. The holes were made by one anisotropic etching step. The fabricated microneedles have
hole diameter and
Intelligent Online Control for Nonlinear Mechanical Systems with Random Friction Effect
Cho, Hyun-Cheol ; Lee, Kwon-Soon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2226~2232
This paper presents online neural control approach for nonlinear mechanical systems with random friction nature. We construct neural auxiliary control to compensate a control error in online for overcoming friction effect which reduces control performance in real-time implementation. Friction dynamics is estimated by using online least square(LS) method, which is utilized for online learning of the neural network. We accomplish computer simulation for evaluating the proposed control approach comparing offline control method to demonstrate its superiority.
Modelling of High-Speed Pantograph and Controller Design Using Disturbance Observer
Jo, Nam-Hoon ; Lee, Kang-Hyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2233~2239
The pantograph-catenary system is one of important components for high-speed rail system that are powered electrically. Electrical power is delivered from a catenary structure to the train via a pantograph and thus it is very important to regulate the contact force between catenary and pantograph. Although a lot of research results for active pantograph have been reported, most of them have made an unrealistic assumption that the catenary displacement is constant with respect to the time. In this paper, we present a new pantograph model that regards the catenary displacement as an unknown disturbance input. Moreover, a disturbance observer based controller is proposed to remove the effect of disturbance, i.e., the catenary displacement variation. The computer simulation result shows that the substantial improvement in regulating the contact force can be achieved by the proposed controller.
Frequency Analysis Method for Linear Optically Coupled Isolation Amplifier
Ahn, Hee-Wook ; Sung, Young-Whee ; Kim, San-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2240~2246
Optically coupled linear isolation amplifier requires special care to avoid oscillation in actual applications. In this paper methods to analyze the frequency characteristics of the amplifier are proposed to reveal the cause of oscillation and to provide design guidelines. The loop gain of the amplifier obtained through the equivalent circuit model shows that the phase margin is too small to ensure stable operations. Methods to get non-oscillatory response are proposed and the resulting frequency responses are analyzed. The common method adding a small capacitor to the amplifier is shown to degrade the frequency bandwidth. The frequency response of output voltage explains the need of filter capacitor in output stage. The usefulness of the method is verified through experiments.
A Forward/Reverse API Translator for Real-Time Operating System Based on a Model-Driven Approach
Park, Byeong-Ryul ; Maeng, Ji-Chan ; Lee, Jong-Bum ; Ryu, Min-Soo ; Ahn, Hyun-Sik ; Jeong, Gu-Min ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2247~2250
This paper presents an automated API translator for embedded software development based on a model-driven approach. Since MDA(Model Driven Architecture) provides little support for the development of embedded software, we propose a new approach containing its advantages. First, we define #generic APIs# which do not depend on any RTOS#s but provide most of typical RTOS services. We can describe RTOS-related behaviors of target application using these generic APIs in a CIC(Common Intermediate Code). Then, we propose a transformation tool for translating between a CIC using generic APIs and a C-code for specific RTOS. The proposed API translator converts them using XML transformation rule which is defined outside. It indicates that an API translator extends to other RTOS#s by modifying or adding the transformation rule. From the experiment. we validate the proposed method.
A Study on the Lossless Image Compression using Context based Predictive Technique of Error Feedback
Chu, Hyung-Suk ; Park, Byung-Su ; An, Chong-Koo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2251~2256
In this paper, the wavelet transform based lossless image compression algorithm is proposed. The proposed algorithm transforms the input image using 9/7 ICFB and S+P filter, and eliminates the spacious correlation of the subband coefficients, applying the context modeling predictive technique based on the multi-resolution structure and the feedback of the prediction error. The prediction context exploits the subordination and direction property of the different level subband in the vertical, horizontal, and diagonal subband coefficients. The simulation result of the high frequency images such as PEPPERS, BOAT, and AIRPLANE shows that the proposed algorithm efficiently predicts the edge area of each multi-resolution subband.
The Novel Low-Voltage High-Gain Transresistance Amplifier Design
Kim, Byoung-Wook ; Bang, Jun-Ho ; Cho, Seong-Ik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2257~2261
A new CMOS transresistance amplifier for low-voltage analog integrated circuit design applications is presented. The proposed transresistance amplifier circuit based on common-source and negative feedback topology is compared with other recent reported transresistance amplifier. The proposed transresistance amplifier achieves high transresistance gain, gain-bandwidth with the same input/output impedance and the minimum supply voltage
. Hspice simulation using 1.8V TSMC
CMOS technology was performed and achieved
transresistance gain which is above the maximum about
compared to transresistance gain of the reported circuit.
Distributed Proportional Fair Scheduling for Wireless LANs
Park, Hyung-Kun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2262~2264
In this paper, we propose a distributed opportunistic scheduling scheme for wireless LAN network. Proportional fair scheduling is one of the opportunistic scheduling schemes and used for centralized networks, whereas we design distributed proportional fair scheduling (DPFS). In the proposed DPFS scheme, each receiver estimates channel condition and calculates independently its own priority with probabilistic manner, which can reduce excessive probing overhead required to gather the channel conditions of all receivers. We evaluate the proposed DPFS using extensive simulation and simulation results show that DPFS obtains up to 23% higher throughput than conventional scheduling schemes and has a flexibility to control the fairness and throughput by controlling the system parameter.
Comparison of Local and Global Fitting for Exercise BP Estimation Using PTT
Kim, Chul-Seung ; Moon, Ki-Wook ; Eom, Gwang-Moon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 56, issue 12, 2007, Pages 2265~2267
The purpose of this work is to compare the local fitting and global fitting approaches while applying regression model to the PTT-BP data for the prediction of exercise blood pressures. We used linear and nonlinear regression models to represent the PTT-BP relationship during exercise. PTT-BP data were acquired both under resting state and also after cycling exercise with several load conditions. PTT was calculated as the time between R-peak of ECG and the peak of differential photo-plethysmogram. For the identification of the regression models, we used local fitting which used only the resting state data and global fitting which used the whole region of data including exercise BP. The results showed that the global fitting was superior to the local fitting in terms of the coefficient of determination and the RMS (root mean square) error between the experimental and estimated BP. The nonlinear regression model which used global fitting showed slightly better performance than the linear one (no significant difference). We confirmed that the wide-range of data is required for the regression model to appropriately predict the exercise BP.