권호 표지

The Transactions of The Korean Institute of Electrical Engineers (전기학회논문지)

The Korean Institute of Electrical Engineers

  • Monthly
  • /
  • 1975-8359(pISSN)
  • /
  • 2287-4364(eISSN)

Aim & Scope

The first issue of The Transactions of the Korean Institute of Electrical Engineers(KIEE) was in October 1948. The Transactions of the KIEE is a monthly periodical published on the 1st day of each month. KIEE is an official publication of the Korean Institute of Electrical Engineers. The aim of the journal is to publish the highest quality manuscripts dedicated to the advancement of electrical engineering technologies. The Journal contains papers related to electrical power engineering, electrical machinery and energy conversion systems, electro-physics and application, information and controls, as well as electrical facilities. Currently, KIEE Transactions is divided into: “A” Sector (Power Engineering); “B” Sector (Electrical Machinery and Energy Conversion System); “C” Sector (Electro-physics and Application); “D” Sector (Information and Control); and “E” Sector (Electrical Facilities). With an aim to collect and publish outstanding scientific papers related to electrical engineering, the topics of papers published in KIEE Transactions are further divided into: power systems, transmission and distribution systems, electric power system economics, micro-grid, power system protection and automation, pumped-storage hydro power generation and electric energy storage systems in the “A” Sector; electrical equipment and appliances, power electronics, electrical traffic systems, new and renewable energy systems, eco-friendly electric power equipment, super-conductive equipment and E-mobility in the “B” Sector; electrical materials and semiconductors, smart large power and high voltage technology, optoelectronics and electromagnetic waves, Micro Electro Mechanical Systems (MEMS), and power asset risk management in the “C” Sector; instrumentation and control (I&C), robotics and automation, computer intelligence and intelligence systems, signal processing and embedded systems, autonomous moving object information processing, and biomedical engineering in the “D” Sector; and engineering and supervision, construction technology, power distribution system diagnosis, safety technology, electric railroad, technical standards, LVDC Facility, electric Facility fusion, etc. in the “E” Sector

http://www.trans.kiee.or.kr/ KSCI KCI SCOPUS

Volume 59 Issue 12

  1. Lee, Hee-Tae;Moon, Jong-Fil;Kim, Jae-Chul 2119
    https://doi.org/10.5370/KIEE.2010.59.12.2119 PDF KSCI
    Reliability evaluation of power distribution system is the evaluation for all customers supplied from one power source as main transformer located in substation. However, power sources include not only the main transformer but distributed generations. Typical reliability evaluation has focused on configuration of power system with one source including failure rates of equipment. In this paper, we focus on not only configuration but power sources as distributed generations. New reliability evaluation method using power supplied probability (PSP) is proposed. The proposed evaluation method are proved through case studies.
  2. Huh, Jae-Sun;Kang, Byoung-Wook;Shin, Hee-Sang;Kim, Jae-Chul 2125
    https://doi.org/10.5370/KIEE.2010.59.12.2125 PDF KSCI
    The neutral section on electric railway system is significant sector in order to prevent short circuit of two electric powers. However, while electric trains pass the neutral section, those speed is decreased and the accident of AC electric traction system and the electric train would be occurred. So the countermeasures are urgently needed. The automatic power switching technology system that is current being research and development is system to improve these problems. Because main object of this system is power change using static switch in the neutral section, it's expected to cause a variety of transients. Especially, onboard transformer inrush current for electric railway train can be occurred more than rated current according to switching time. Therefore, the analysis and improvement are needed to ensure the stability of this system. In this paper, we analyze the operating characteristics of the automatic power switching technology system. Especially, it reviews inrush current according to the closing phase angle. And we propose control plan of inrush current considering the case that voltage is maintained due to counter electromotive force and regenerative braking operation of electric railway train. Finally, the proposed control scheme was reviewed using the transient analysis program.
  3. Chang, Byung-Hoon;Moon, Seung-Pil;Ha, Yong-Gu;Jeon, Woong-Jae 2131
    https://doi.org/10.5370/KIEE.2010.59.12.2131 PDF KSCI
    In this paper, the on-line system schemes for coordinated control system of multiple FACTS were presented to enhance the voltage stability around the metropolitan areas. In order to coordinated control system of FACTS devices, MFC on-line system calculates the optimal set point(Vref, Qrev) of FACTS devices using the coordinated control algorithm with real time network data which is transferred from SCADA/EMS system. If the system is unstable after contingencies, the new operation set-point of FACTS would be determined using bus sensitivity from tangent vector at voltage instability point. Otherwise, we would determine the new operation set-point of FACTS for considering economical operation, like as active power loss minimization using Optimal Power Flow algorithm. As the test, MFC(Multiple FACTS Coordinated control) on-line system will be installed in Korea power system.
  4. Jeong, Seok-San;Lee, Jong-Beom;Kim, Yong-Kap;Song, Il-Keun;Kim, Byoung-Suk 2135
    https://doi.org/10.5370/KIEE.2010.59.12.2135 PDF KSCI
    This paper studies the validity about a joint operation of neutral wire and overhead grounding wire in combined distribution systems. The overhead grounding wire and neutral wire are currently installed separately and grounded by common. However there is no any ineffectiveness or electrical problem in case of the proposed system, such system can be operated at real distribution system. Therefore this paper describes the suitability of a joint operation through lightning surge analysis on combined distribution systems. Lightning surge analysis is carried out by EMTP/ATPDraw to obtain the overvoltage of overhead line and underground cable in various conditions such as locations and current types of lightning stroke. Overvoltage gained by the analysis show that the insulation strength of the joint operation case is not stable compare with the current operation case.
  5. Lee, Kwang-Ho;Cho, Sung-Wi 2143
    https://doi.org/10.5370/KIEE.2010.59.12.2143 PDF KSCI
    Market price and curtailment amounts of the Demand Resource Market(DRM) are determined by competition between electricity consumers. An important aspect of the DRM involves the assessment of strategic behavior of participants for maximizing their profits. This paper presents economic equilibrium models for simulating imperfect competition among electricity consumers in the DRM and analyzes the models at Nash Equilibrium of Game Theory. The proposed demand functions and supply functions of DRM are based on the Demand Resource Market Rules in Korean electricity market. Simulation results show that the models are adequate for obtaining Nash Equilibrium of consumers' competitive curtailment.
  6. Kim, Jin-Ho;Park, Jong-Bae 2150
    https://doi.org/10.5370/KIEE.2010.59.12.2150 PDF KSCI
    In this paper, we investigate how an electricity capacity market design may encourage generators to exaggerate their available capacity. In order for an analytical approach, a two player game model is introduced. We focus on two pure strategy Nash equilibria: an equilibrium at which generators offer their true capacities, and an equilibrium at which generators offer exaggerated capacities. The latter case is caused by asymmetries of information between players and so called 'moral hazard' in terms of the economics literature. This paper shows that, considering practical electricity markets, the moral hazard case is highly probable. Moreover, it is shown that, with the considered capacity market design in the real world, the better the electricity energy market performs, the higher the risk of moral hazard becomes.
  7. Choi, Eun-Sik;Choi, Heung-Kwan;Jeon, Jin-Hong;Ahn, Jong-Bo 2157
    https://doi.org/10.5370/KIEE.2010.59.12.2157 PDF KSCI
    Microgrid is generally defined as cluster of small distributed generators, energy storages and loads. Through monitoring and coordinated control, microgrid can provide various benefits such as reduction of energy cost, peak shaving and power quality improvement. In design stage of microgrid, system dynamic simulation is necessary for optimizing of sizing and siting of DER(distributed energy resources). As number of the system components increases, simulation time will be longer. This problem can restrict optimal design. So we used simplified modeling on energy sources and average switching model on power converters to reduce simulation time. The effectiveness of this method is verified by applying to prototype microgrid system, which is consist of photovoltaic, wind power, diesel engine generators, battery energy storage system and loads installed in laboratory. Simulation by Matlab/Simulink and measurements on prototype microgrid show that the proposed method can reduce simulation time not sacrificing dynamic characteristics.
  8. Jyung, Tae-Young;Baek, Young-Sik 2165
    https://doi.org/10.5370/KIEE.2010.59.12.2165 PDF KSCI
    This paper presents the operation algorithm of microgrid on the Real Time Pricing(RTP) for building the smart grid. RTP is higher power price variability than flat rate and time of use. However it has an effect on peak clipping and peak load shifting due to the increased price on peak time power demand. When the RTP are applied to the microgrid system, the proposed algorithm is able to be effective and economic operation. The implemented system is operated for the economic operation in microgrid connected with the power system. On the other hand, when the microgrid is operated on isolation mode, it focus on the improvement of stability and the power supply reliability of the sensitive loads. The test system are implemented and calculated on various operation modes based on non-dispachable generator output and RTP data for validating the proposed operation algorithm. The calculated results are compared to the implemented results using real-time simulator. It can be confirmed that the proposed operation system are identical results to the calculated one. When the proposed operation algorithm is applied to the system, it can be show the effectiveness of the peak clipping and peak load shifting and the improvement of economic feasibility.
  9. Baek, Soo-Hyun 2173
    https://doi.org/10.5370/KIEE.2010.59.12.2173 PDF KSCI
    The magnetization directions of a polar magnetized ferrite bonded magnet are analyzed by finite element method (FEM). The influence of the width of SmCo magnets for magnetic field generation is investigated. The surface flux densities of the polar anisotropic magnets are analyzed and compared according to the pole number and thickness of the magnets. And the electromotive force (EMF) values of brushless DC motors with the magnets are investigated. The validity of the analysis method is verified by comparing the analyzed results with measured ones.
  10. Jang, Seok-Myeong;Ko, Kyoung-Jin;Choi, Jang-Young 2179
    https://doi.org/10.5370/KIEE.2010.59.12.2179 PDF KSCI
    This paper deals with analytical techniques for performance evaluation of small scaled wind power generator with outer permanent magnet rotor. In part (1), using transfer relations theorem, magnetic field distribution characteristics by PM and armature reaction field are derived. Moreover, electrical parameters such as back-EMF, inductance and resistance are calculated from the obtained field characteristic equations. The proposed analytical techniques are validated by nonlinear finite element method using commercial software 'Maxwell' and performance experiments of the manufactured generator. In part (2), generating characteristics analysis such as constant speed characteristics and constant resistive load characteristics, and performance evaluation according to variation of wind speed will be accomplished using the derived electrical parameters.
  11. Kim, A-Rong;Kim, Gyeong-Hun;Kim, Jin-Geun;Park, Min-Won;Yu, In-Keun;Lee, Sang-Jin;Park, Jung-Do;Yi, Dong-Young 2190
    https://doi.org/10.5370/KIEE.2010.59.12.2190 PDF KSCI
    Wind power generation system (WPGS) of Ulleung Island causes frequency and voltage fluctuation due to wind speed variation during night time. Superconducting magnetic energy storage (SMES) system can overcome the fluctuations through the fast response time of energy charging and discharging. The SMES system should be connected to the terminal of the WPGS for frequency stabilization. To demonstrated the effectiveness of SMES system for power quality improvement, Ulleung Island power network was modeled in a real time digital simulator (RTDS). The RTDS-based simulation results of power quality improvement with SMES are investigated and discussed in detail.
  12. Kim, Young-Seok;Seok, Bong-Jun;La, Jae-Du 2195
    https://doi.org/10.5370/KIEE.2010.59.12.2195 PDF KSCI
    The VBC(Voltage Bus Conditioner) is a bidirectional DC-DC converter with the energy storage for damping the instability and any transients of bus voltage in the DC DPS(Distributed Power System). This paper presents the PI(Proportional Integration) controller for the VBC. The PI controller is not only damping the bus transient, but also keeping the storage voltage level. Matlab Simulink simulation and experimental results are presented by validity of the proposed control technique.
  13. Lee, Young-Mi;Yoo, Myoung-Suk;Choi, Hong-Seok;Kim, Yong-Jun;Seo, Young-Jun 2202
    https://doi.org/10.5370/KIEE.2010.59.12.2202 PDF KSCI
    The wind power prediction system is composed of a meteorological forecasting module, calculation module of wind power output and HMI(Human Machine Interface) visualization system. The final information from this system is a short-term (6hr ahead) and mid-term (48hr ahead) wind power prediction value. The meteorological forecasting module for wind speed and direction forecasting is a combination of physical and statistical model. In this system, the WRF(Weather Research and Forecasting) model, which is a three-dimensional numerical weather model, is used as the physical model and the GFS(Global Forecasting System) models is used for initial condition forecasting. The 100m resolution terrain data is used to improve the accuracy of this system. In addition, optimization of the physical model carried out using historic weather data in Jeju. The mid-term prediction value from the physical model is used in the statistical method for a short-term prediction. The final power prediction is calculated using an optimal adjustment between the currently observed data and data predicted from the power curve model. The final wind power prediction value is provided to customs using a HMI visualization system. The aim of this study is to further improve the accuracy of this prediction system and develop a practical system for power system operation and the energy market in the Smart-Grid.
  14. Ji, Yang-Geun;Kong, Ji-Hyun;Kang, Gi-Hwan;Yu, Gwon-Jong;Ahn, Hyung-Gun;Han, Deuk-Young 2212
    https://doi.org/10.5370/KIEE.2010.59.12.2212 PDF KSCI
    Previous studies have been focused on the voltage of Bypass diode and Isc(Short Circuit Current) of the influenced solar cell. The Bypass diode starts working when it gets the reverse applied voltage. Previous studies have only concentrated on Isc of the influenced solar cell and Imp of PV module to explain the bypassing performance. PV module is usually working together with inverter having MPPT(Maximum Power Point Tracking) function for best performance. bypassing point is regulated by MPPT function of inverter. In this paper, simulation results of Bypass diode in PV module have been analyzed to represent the relationship of the bypassing point with the composition of PV module. From the results, the more cells are connected with each string, the earlier bypassing performance happens under the fixed number of strings. As diode groups increase or irradiation decreases, the bypassing performance starts fast.
  15. Son, Min-Kyu;Seo, Hyun-Woong;Shin, In-Young;Kim, Jin-Kyoung;Choi, Jin-Ho;Choi, Seok-Won;Kim, Hee-Je 2218
    https://doi.org/10.5370/KIEE.2010.59.12.2218 PDF KSCI
    Dye-sensitized solar cell (DSC) is a promising alternative solar cell to the conventional silicon solar cell due to several advantages. Development of large scale module is necessary to commercialize the DSC in the near future. A scribing technology of the transparent conductive oxide (TCO) is one of the important technologies on the fabrication of DSC module. A quality of the scribed line on the TCO has a decisive effect on the efficiency of DSC module. Among several scribing technologies, the fiber laser is a suitable for scribing the TCO more precisely and accurately because of their own characteristics. In this study, we try to improve the quality of the TCO scribed line by using the fiber laser. Consequently, the operating parameter of fiber laser is optimized to get the TCO scribed line with good quality. And the fiber laser scribing technology of the TCO is applied to the fabrication of the DSC with optimal operating parameter, operating current 3900mA. As a result, the current density and fill factor are improved and the total efficiency is increased because the internal resistances of DSC such as TCO sheet resistance and the resistance concerned to the electron movement in the $TiO_2$ are reduced. This is analyzed by the electrochemistry impedance spectroscopy (EIS) and the equivalent circuit model of the DSC.
  16. Choe, Su-Il;Lee, June-Ho;Kim, Gyu-Eon;Kim, Jong-Min;HwangBo, Seung 2225
    https://doi.org/10.5370/KIEE.2010.59.12.2225 PDF KSCI
    In this study, we have investigated the effects of space charge on the conduction current with the variation of applied time of electric field in polymer insulators. We had also improved the PEA method, and then we could measure a simultaneously the space charge and the conduction current in insulators under the DC electric field. From this experiment, we have known the variation of conduction current due to the existence of space charge in XLPE1 and XLPE2.
  17. Lim, Kyung-Bum;Kim, Jong-Yoon;Choi, Hoon-Young 2230
    https://doi.org/10.5370/KIEE.2010.59.12.2230 PDF KSCI
    This paper deals with the change of surface potential decay, surface resistivity, contact angle and XPS of ultraviolet-treated PET films. From the experimental results on the surface potential decay of UV degraded-samples, it was found that the accumulation of charge is decreased and the surface potential decay time is shortened. Also, from the result of XPS, it was found that the changes affected by the surface degradation of PET film were caused by the generation of carboxyl groups through the chain decomposition and recombination with oxygen molecules in the air.
  18. Kim, Yong-Hyuk 2235
    https://doi.org/10.5370/KIEE.2010.59.12.2235 PDF KSCI
    In this study, The cation exchange membrane and the anion exchange membrane affect in electrical conduction of metal fuel cell was investigated. Magnesium material as anode electrode and the NaCl solution dissolved with 5~15wt% as electrolyte were used for the metal fuel cell. It was found that magnesium slag where flows toward the air electrode was suppressed by using ion exchange membrane. The open circuit voltage variation during discharge has very flat pattern by using ion exchange membrane, but the case which is not the exchange membrane, the open circuit voltage increased according to time. When using the anion exchange membrane, the electric current was higher case of the cation exchange membrane, as a result of higher equivalent conductivity in anion Cl-. The cation exchange membrane was observed with the fact that the output power is excellent in compared with anion exchange membrane.
  19. Kim, Dong-Eun;Kim, Byoung-Sang;Kim, Gyong-Chol;Shin, Hoon-Kyu;Kwon, Young-Soo 2240
    https://doi.org/10.5370/KIEE.2010.59.12.2240 PDF KSCI
    We have studied white OLED using two types of Zn-complexes as a emitting layer. We synthesized new emissive materials $Zn(HPQ)_2$ as a yellow emitting material and $Zn(HPB)_2$ as a blue emitting material. Zn-complexes have a low molecular compound and thermal stability. The fundamental structures of the fabricated OLED was ITO / NPB (40nm) / $Zn(HPB)_2$ (30nm) / $Zn(HPQ)_2$ / LiF / Al. We varied the thickness of the $Zn(HPQ)_2$ layer 20, 30 40 nm. When the thickness of the $Zn(HPQ)_2$ layer was 20 nm, white emission was achieved. The maximum luminance was 12,000 cd/$m^2$ at a current density of 800 mA/$cm^2$. The CIE coordinates of the white emission was (0.319. 0.338) at an applied voltage of 10 V.
  20. Yang, Chang-Heon;Kim, Gyong-Chol;Kwon, Young-Soo;Shin, Hoon-Kyu 2245
    https://doi.org/10.5370/KIEE.2010.59.12.2245 PDF KSCI
    The physical properties of the LB films with merocyanine dyes have been published and attract attention due to the possibility of molecular structure control. The evaluation of the thin films was focused for the purpose of molecular structure control. The molecular structure in the case of the thin films with dyes can be examine by optical absorption spectra measurements. In the result measured by optical absorption spectra, the $[DX]_{1-x}[DO]_x$ LB films shows a large in-plane anisotropy and the transition dipole moment of red-shifted band is preferentially oriented perpendicular to the dipping direction of the film, while that of the blue-shifted band prefers the dipping direction. The spectrum for $0_{\circ}$, $90_{\circ}$-polarized light coincides with the spectrum for non-polarized light and also with the spectrum was observed in the LB film deposited using a fresh solution. These results show that the aging process does not cause a structural change in chromophore but a change in the degree of molecular orientation. In the results, study of the merocyanine dyes LB films using optical absorption spectra would an interesting problem of absorbance peak shifts and mixed components.
  21. Moon, Jae-Duk 2250
    https://doi.org/10.5370/KIEE.2010.59.12.2250 PDF KSCI
    An fine silver particle has a variety of uses, such as in killing micrograms and as catalysts. Many techniques have been used for the production of the fine particles. Faraday cell, consisting of two silver electrodes in an electrolyte, is unique, but it is hard to get a very fine particle by this method. A finer silver nano-particle producing cell, utilizing a dielectric bed as a lower electric current and higher field controlling means, has been proposed and investigated. The I-V characteristics of the cell and effect of the dielectric bed on the producing finer silver nano-particles have been investigated. The I-V characteristics of the cell with the dielectric bed were different from that of the same system without the bed, due to the increased cell resistance and elevated electric field intensity. It is found that the proposed cell with the dielectric bed can produce finer silver nano-particles effectively, which, however, can be used as one of effective fine silver nano-particle producing means.
  22. Jung, Jae-Seung;Moon, Jae-Duk 2256
    https://doi.org/10.5370/KIEE.2010.59.12.2256 PDF KSCI
    A corona discharge system with needle point or wire type corona electrode has been well used as an ionic wind blower. The corona discharge system with a needle point electrode produces ions at lower applied voltage effectively. However, the corona discharge on the needle point electrode transits to the arc discharge at lower voltage, and it is hard to obtain the elevated electric field in the discharge airgap for enhancing the ion migration velocity due to the weak Coulomb force. A cylindrical corona electrode with sharp round tip is reported as one of effective corona electrode, because of its higher breakdown voltage than that of the needle electrode. A basic study, for the effectiveness of cylindrical electrode shape on the ionic wind generation, has been investigated to obtain an maximum wind velocity, which however is the final goal for the real field application of this kind ionic wind blower. In this paper, a parametric study for maximizing the ionic wind velocity utilizing the cylindrical corona electrode and a maximum ion wind velocity of 4.1 m/s were obtained, which is about 1.8 times higher than that of 2.3m/s obtained with the needle corona electrode from the velocity profile.
  23. Kim, Woo-Young;Lee, Se-Il;Yang, Jong-Kyung;Jeong, Young-Gi;Park, Dae-Hee 2262
    https://doi.org/10.5370/KIEE.2010.59.12.2262 PDF KSCI
    In order to analyze the reason of wall blackening, which affect the decline of lifetime in a ceramic metal halide lamp, we carried out the deterioration of ceramic tubes by a change in operating conditions with arc tubes of two types of spherical and cylindrical, and we have confirmed the cause of wall blackening through the analysis of element composition and spectrum from SEM/EDS and spectrum analyzer. Wall blackening of tungsten was shown by sputtering from ignition in 20 minute on/off condition and wall blackening from chemical reaction between PCA wall and rare earth halides was shown significantly in a condition without on/off test. Especially, the wall blackening and the decline of luminous flux were reduced by inner convection in spherical type arc tube. Moreover, the color temperature and color coordinate were changed by reduction of emission spectrum of Dy which causes the chemical reaction with PCA wall.
  24. Seo, Ki-Won;Kim, Jung-Han;Roh, Hyoung-Hwan;Seong, Yeong-Rak;Oh, Ha-Ryoung;Park, Jun-Seok 2268
    https://doi.org/10.5370/KIEE.2010.59.12.2268 PDF KSCI
    This letter presents that a rectenna can utilize more stable wireless power by using a new design dual band/dual polarization microstrip patch antenna and 2 stage voltage multiplier at 2.4 GHz band and 3.1 GHz band. The proposed antenna is a new microstrip patch antenna design to make impedance matching possible by using slotted capacitive coupling between the patch and $50\Omega$ feed line on a ground plane. Its advantage is that the size of the rectenna can be reduced by using $50\Omega$ feed line on the ground plane, which can be used efficiently. The dual band/dual polarization microstrip patch antenna shows circular polarization at 2.4 GHz band and linear polarization at 3.1 GHz band. Under -10 dB return loss, The dual band/dual polarization microstrip patch antenna obtains 340 MHz bandwidth as 2.23~2.57 GHz and 375 MHz bandwidth as 2.95~3.325 GHz. Also, 2 Stage Voltage multiplier is possible to operate at 2.4 GHz band and 3.1 GHz band. The designed retenna can usually obtain wireless power at both 3.1 GHz band, and 2.4 GHz band applications such as Wi-Fi, Bluetooth, Wireless LAN, etc. So more stable wireless power can be utilized at the same time.
  25. Kim, Jong-Bum;You, Chong-Ho;Choi, Hyuk-San;Hwang, In-Gab 2273
    https://doi.org/10.5370/KIEE.2010.59.12.2273 PDF KSCI
    In this paper a 2.4GHz CMOS colpitts type microwave oscillator was designed and fabricated using H-spice and Cadence Spetre. There are 140MHz difference between the oscillation frequency and the resonance frequency of a tank circuit of the designed oscillator. The difference is seemed to be due to the parasitic component of the transistor. The inductors used in this design are the spiral inductors proposed in other papers. Cascode current source was used as a bias circuit of a oscillator and the output transistor of the current source is used as the oscillation transistor. A common drain buffer amplifier was used at the output of the oscillator. The measured oscillation frequency and output power of the oscillator are 2.173GHz and -5.53dBm.
  26. Jeon, Jeong-Hyo;Kim, Cheol-Joong;Chwa, Dong-Kyoung 2278
    https://doi.org/10.5370/KIEE.2010.59.12.2278 PDF KSCI
    This paper deals with the pendubot control using disturbance observer. Experimental results for the motion of pendubot with balancing control show that the limit cycle can be attributed to the disturbance. Therefore, we propose the disturbance compensation method using by disturbance observer to compensate for the disturbance. Through the experimental results, the effectiveness of the proposed method is verified.
  27. Kwon, Oh-Min;Park, Ju-Hyun;Lee, Sang-Moon 2284
    https://doi.org/10.5370/KIEE.2010.59.12.2284 PDF KSCI
    In this paper, improved stability criteria for linear systems with time-varying delays are proposed. By constructing a new Lyapunov functional, novel stability criteria are established in terms of linear matrix inequalities (LMIs). Two numerical examples are carried out to support the effectiveness of the proposed method.
  28. Kim, Won-Hee;Chung, Chung-Choo 2292
    https://doi.org/10.5370/KIEE.2010.59.12.2292 PDF KSCI
    To improve the performances of Sawyer motors and to regulate yaw rotation, various feedback control methods have been developed. Almost all of these methods require information on the position, velocity or full state of the motor. Therefore, in this paper, a nonlinear observer is designed to estimate the full state of the four forcers in a Sawyer motor. The proposed method estimates the full state using only positional feedback. Generally, Sawyer motors are operated within a yaw magnitude of several degrees; outside of this range, Sawyer motors step out. Therefore, this observer design assumes that the yaw is within ${\pm}90^\b{o}$. The convergence of the estimation error is proven using the Lyapunov method. The proposed observer guarantees that the estimation error globally exponentially converges to zero for all arbitrary initial conditions. Furthermore, since the proposed observer does not require any transformation, it may result in a reduction in the commutation delay. The simulation results show the performance of the proposed observer.
  29. Lee, Do-Hyun;Kim, Byeong-Woo;Choi, Jin-Kwon 2298
    https://doi.org/10.5370/KIEE.2010.59.12.2298 PDF KSCI
    The paper presents the Model Based Design(MBD) method which design and verify control algorithm for safety power window. Safety power window are required to work together with the anti-pinch function and have to meet FMVSS118 S5 requirements and equivalent ECC requirements. To meet the requirements, this paper presents the establishment of SILS and RCP environments. The design process can reduce time and support more performance-assured design. As a result of study, it met the regulations and achieved reaction force that close to common products.
  30. Kim, Byeong-Woo;Hur, Jin 2306
    https://doi.org/10.5370/KIEE.2010.59.12.2306 PDF KSCI
    This paper describes a model based fault detection algorithm for an Advanced ESC System which consists of Hydraulic Control Unit (HCU) with built-in wheel pressure sensors. Advanced ESC System can be used for various value-added functions such as Stop & Go Function and Regenerative Brake Function. Therefore, HCU must have a reliable fault detection. Due to the huge amount of sensor signals, existing specific sensor based fault detection of HCU cannot guarantee the safety of vehicle. However, proposed algorithm dose not require the sensors. When model based fault detection algorithm detects severe failures of the HCU, it warns the driver in advance to prevent accidents due to the failures. For this purpose, a mathematical model is developed and validated in comparison to actual data. Simulation results and data acquired from an actual system are compared with each other to obtain the information needed for the fault detection process.
  31. Kim, Jin-Kyu;Joo, Young-Hoon 2314
    https://doi.org/10.5370/KIEE.2010.59.12.2314 PDF KSCI
    For human-robot interaction, a robot should recognize the meaning of human behavior. In the case of static behavior such as face expression and sign language, the information contained in a single image is sufficient to deliver the meaning to the robot. In the case of dynamic behavior such as gestures, however, the information of sequential images is required. This paper proposes behavior classification by using fuzzy classifier to deliver the meaning of dynamic behavior to the robot. The proposed method extracts feature points from input images by a skeleton model, generates a vector space from a differential image of the extracted feature points, and uses this information as the learning data for fuzzy classifier. Finally, we show the effectiveness and the feasibility of the proposed method through experiments.
  32. Jeong, Hyeon-Seok;Joo, Young-Hoon 2319
    https://doi.org/10.5370/KIEE.2010.59.12.2319 PDF KSCI
    The existing contact-type bearings using rolling or sliding require continuous maintenance due to abrasion caused by friction and are not suitable for high-speed rotation and slimming. A magnetic bearing without contact can overcome such problems but the performance depends on the allocation of magnets and the structure of bearings. This paper proposes a method designing parameters of a passive magnetic bearing to improve levitation force. The proposed method employs Halbach array as the allocation of magnets, uses particle swam optimization to determine the structure of bearings. The numerical experiment shows that the levitation force is improved by the proposed method compared with the existing one using finite element analysis.
  33. Jo, Wang-Rae;Choi, Seong-Young;Bae, Myung-Jin 2324
    https://doi.org/10.5370/KIEE.2010.59.12.2324 PDF KSCI
    In this paper we proposed a new algorithm that can reduce the open-loop pitch estimation time of G.723.1. The time domain cross-correlation method is simple but has long processing time by recursive multiplication. For reduction of processing time, we use the method that compute the cross-correlation by multiplying the Fourier value of speech by it's complex conjugate. Also, we can reduce the processing time by omitting the bit-reversing of FFT and IFFT for time-frequency domain transform. As a result, the processing time of improved hybrid domain cross-correlation algorithm is reduced by 67.37% of conventional time domain cross-correlation.
  34. Shin, Hyun-Jae;Ahn, Sae-Young;Jo, Young-Jun;An, Sun-Shin 2329
    https://doi.org/10.5370/KIEE.2010.59.12.2329 PDF KSCI
    Hierarchical tree routing is a inefficient routing method of transmitting data in a wireless sensor network. Zigbee routing which is made to improve inefficiency of the hierarchical tree routing only fulfills the tree routing when a destination node don't exists in neighbor nodes of a router. We suggest a TFSR algorithm that is improved more than the zigbee routing. The TFSR algorithm generates a family set included a parent node and child nodes and over of a destination node, and uses this information. According to simulation results, the TFSR algorithm reduce routing costs over 30 percent in comparison with the hierarchical tree routing and the zigbee routing.
  35. Im, Eun-Hye;Park, Byung-Seok;Kim, Young-Hyun;Choi, In-Ji;Myoung, No-Gil 2337
    https://doi.org/10.5370/KIEE.2010.59.12.2337 PDF KSCI
    AMR(Automatic Meter Reading)/AMI(Advanced Metering Infrastructure) is actively deployed all over the world. efficient, economical, stable and reliable system need to push forward the AMR/AMI business, so various researchs are in progress. In electric power system of domestic, a transformer is connected average twenty to thirty households and PLC is possible to communication within household connected same transformer. So if server and data concentrator unit(DCU) share circuit line through communication between transformers, communication network is able to efficient. Therefore we design new communication method between DCUs and test it and demonstrate the performance.
  36. Cha, Eun-Jong;Choi, Seong-Su;Lee, In-Kwang;Kim, Do-Kyung;Han, Soon-Wha;Kim, Kyung-Ah 2344
    https://doi.org/10.5370/KIEE.2010.59.12.2344 PDF KSCI
    Benign prostatic hyperplasia (BPH) significantly deteriorates the quality of life in aged men. Uroflowmetry is a convenient non-invasive clinical test to diagnose BPH. However, the test is usually performed in the presence of a technician, which may affect the way of urination for the lack of privacy. The present study developed a wireless uroflowmeter to provide the best privacy with a user program on PC evaluating the diagnostic parameters. Pilot experiment was followed to test clinical applicability.
  37. Ryu, Sang-Hun;Kim, Do-Hyun;Song, Chul-Gyu 2349
    https://doi.org/10.5370/KIEE.2010.59.12.2349 PDF KSCI
    Photo Acoustic Tomography (PAT) is a hybrid imaging modality which combines high contrast of optical imaging and spatial resolution of ultrasound imaging, thus it is suitable to image biological tissue noninvasively. Laser-induced photoacoustic signals were measured from a sample by means of an unfocused ultrasound transducer, then PAT image was reconstructed based on a universal back-projection algorithm. To evaluate the feasibility of our system, phantom test was performed, consequently, the PAT images obtained using our system showed highly analogous shape and volume with those of the phantom. This result demonstrated that our system can provide a powerful tool for imaging the substructure of biological tissue in non-invasive manner.