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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 57, Issue 12 - Dec 2008
Volume 57, Issue 11 - Nov 2008
Volume 57, Issue 10 - Oct 2008
Volume 57, Issue 9 - Sep 2008
Volume 57, Issue 8 - Aug 2008
Volume 57, Issue 7 - Jul 2008
Volume 57, Issue 6 - Jun 2008
Volume 57, Issue 5 - May 2008
Volume 57, Issue 4 - Apr 2008
Volume 57, Issue 3 - Mar 2008
Volume 57, Issue 2 - Feb 2008
Volume 57, Issue 1 - Jan 2008
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Fourier Transform-Based Phasor Estimation Method Eliminating the Effect of the Exponentially Decaying DC offsets
Lee, Dong-Gyu ; Kim, Cheol-Hun ; Kang, Sang-Hee ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1485~1490
This paper proposes a new Fourier transform-based phasor estimation method to eliminate the adverse influence of the exponentially decaying dc offsets when Discrete Fourier Transform (DFT) is used to calculate the phasor of the fundamental frequency component in a relaying signal. By subtracting the result of odd-sample-set DFT from the result of even-sample-set DFT, the information of dc offsets can be obtained. Two dc offsets in a relaying signal are treated as one dc offset which is piecewise approximated in one cycle data window. The effect of the dc offsets can be eliminated by the approximated dc offset. The performance of the proposed algorithm is evaluated by using computer-simulated signals and EMTP-generated signals. The algorithm is also tested on a hardware board with TMS320C32 microprocessor. The evaluation results indicate that the proposed algorithm has the stable and accurate eliminating performance even if the input signal contains two decaying dc components having different time constants.
A Study on Probabilistic Reliability Evaluation of Power System Considering Wind Turbine Generators
Park, Jeong-Je ; Wu, Liang ; Choi, Jae-Seok ; Moon, Seung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1491~1499
This paper presents a study on reliability evaluation of a power system considering wind turbine generators (WTG) with multi-state. Renewable energy resources such as wind, wave, solar, micro hydro, tidal and biomass etc. are becoming importance stage by stage because of considering effect of the environment. Wind energy is one of the most successful sources of renewable energy for the production of electrical energy. But, reliability evaluation of generating system with wind energy resources is a complex process. While the wind turbine generators can not modelled as two-state model as like as conventional generators, they should be modelled as multi-state model due to wind speed random variation. The methodology for obtaining reliability evaluation index of wind turbine generators is different from it of the conventional generators. A method for making outage capacity probability table of WTG for reliability is proposed in this paper. The detail process is presented using case study of simple system.
A Study on Reliability Characteristic Curve of Transmission & Substation System considering Device Fault's Uncertainty
Jeon, Dong-Hoon ; Kim, Kern-Joong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1500~1506
In this paper, we proposed new reliability characteristic curve, which-can clearly show reliability property of transmission and substation system considering uncertainty such as frequency and duration of device fault. It express the relationship of duration of load curtailments, demand not supplied, and energy not served as “ y =
" curve. and we proposed the method, which can objectively assess reliability of transmission and substation system using proposed characteristic curve as new reliability index. In this method, we used energy index of reliability(EIR) as a criterion of assessment. Finally, we performed a variety of case study for KEPCO system in order to verify usefulness of proposed method.
Fault Pattern Analysis and Restoration Prediction Model Construction of Pole Transformer Using Data Mining Technique
Hwang, Woo-Hyun ; Kim, Ja-Hee ; Jang, Wan-Sung ; Hong, Jung-Sik ; Han, Deuk-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1507~1515
It is essential for electric power companies to have a quick restoration system of the faulted pole transformers which occupy most of transformers to supply stable electricity. However, it takes too much time to restore it when a transformer is out of order suddenly because we now count on operator in investigating causes of failure and making decision of recovery methods. This paper presents the concept of 'Fault pattern analysis and Restoration prediction model using Data mining techniques’, which is based on accumulated fault record of pole transformers in the past. For this, it also suggests external and internal causes of fault which influence the fault pattern of pole transformers. It is expected that we can reduce not only defects in manufacturing procedure by upgrading quality but also the time of predicting fault patterns and recovering when faults occur by using the result.
Typical Daily Load Profile Generation using Load Profile of Automatic Meter Reading Customer
Kim, Young-Il ; Shin, Jin-Ho ; Yi, Bong-Jae ; Yang, Il-Kwon ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1516~1521
Recently, distribution load analysis using AMR (Automatic Meter Reading) data is researched in electric utilities. Load analysis method based on AMR system generates the typical load profile using load data of AMR customers, estimates the load profile of non-AMR customers, and analyzes the peak load and load profile of the distribution circuits and sectors per every 15 minutes/hour/day/week/month. Typical load profile is generated by the algorithm calculating the average amount of power consumption of each groups having similar load patterns. Traditional customer clustering mechanism uses only contract type code as a key. This mechanism has low accuracy because many customers having same contract code have different load patterns. In this research, We propose a customer clustring mechanism using k-means algorithm with contract type code and AMR data.
Recursive Real Time Fault Locator with Wavelet Method
Lee, Sung-Woo ; Ha, Bok-Nam ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1522~1530
This paper presents a discrete wavelet analysis based algorithm to address the fault impedance calculation under transient state in radial power distribution networks. The fault impedances have been derived under different fault conditions. Furthermore, a recursive fault distance estimation method is proposed utilizing the measured fault impedance and power line parameters. The proposed scheme can resolve the errors caused by the non-homogeneous power lines, the presence of lateral loads since, the fault impedance will always be updated with the recursive form. For the verification of the proposed scheme, a filed test has been peformed with varying fault resistances in the 22.9(kV) radial system. Power meters and fault locators were installed at the substation. It was figured out that the performance of the discrete wavelet and the recursive scheme are very good even for high fault resistance condition.
A Study on the Capacity Payment in Cost Based Pool
Han, Seok-Man ; Kim, Balho H. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1531~1535
In the past vertically integrated power system, the power utility forecasted power demand and invested new power plants to keep a system adequacy. However, in the competitive electricity markets, a principle part of the capacity investment is market participants who decided the investment to maximize their profit. Especially, one of the main factors in their long-term decision making is the retrieval of fixed costs (construction costs). This paper presents the capacity payment in electricity power markets. The capacity payment (CP) in Cost Based Pool (CBP) is needed to recover fixed costs. However, CP in CBP was applied not only recovering fixed costs but also ensuring supply reliability. In order to operate harmonious power markets, pool needs reasonable CP mechanism. This paper analysis CP using capacity proportion and Reliability Pricing Model (RPM).
Design Methodology for Minimal Stator Copper Loss in A Single-phase Induction Motor
Baek, Soo-Whang ; Kim, Byung-Taek ; Kwon, Byung-Il ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1536~1545
In this paper, we research a new method for efficiency improvement of a single-phase Induction motor by minimization of the stator loss. To make this, we perform winding design which is based on balanced and quasi-balanced operation condition. It gives efficiency improvement greatly but poor starting torque simultaneously. To obtain the best efficiency improvement maintaining the maximum and starting torque, the optimal winding specification and rotor dimension is determined with variation of secondary resistance, running capacitor and turn ratio. Finally, this paper gives the comparison between the simulation results and experimental results.
Study on Losses Segregation for Capacitor-Run Single Phase Induction Motor
Kim, Kwang-Soo ; Kim, Ki-Chan ; Lee, Sung-Gu ; Go, Sung-Chul ; Chun, Yon-Do ; Lee, Chul-Kyu ; Lee, Ju ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1546~1551
This paper is concerned with the problems of accurate losses segregation in capacitor-run single phase motor. Segregation of losses in single phase induction motor is more complicated than that in three phase induction motor, because of the backward magnetic field component in the motor. Generally there are two methods for losses segregation of single phase induction motor. The one is relatively complicated method based on parameter estimation of single phase induction motor. By the way, the other one is simplified method based on IEEE Standard 114. All of the methods for the experimental determination of single phase induction motor losses are studied in this paper. Since the IEEE Standard is not possible to be applied for all type of single phase induction motors, we modified that method to apply for losses segregation of capacitor-run single phase induction motor as unifying the method based on parameter estimation.
Sensorless Speed Control of Induction Motor by an Improved Sliding Mode Observer
Jang, Min-Young ; Kim, Sang-Kyoon ; Kwon, Young-Ahn ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1552~1554
Recently, sensorless induction motor drives have been much studied due to several advantages. Sensorless drives eliminate the additional mounting space, increase the reliability in harsh environments, and reduce the cost of a motor. This paper investigates an improved sliding mode observer for the sensorless speed control of an induction motor. The proposed control strategy is the sliding mode observer with a variable boundary layer for a low-chattering and fast-response control. The proposed sensorless-algorithm is verified through the simulation and experimentation.
Cooling System Development of BIPV Module Using Thermoelectron
Choi, Jung-Sik ; Ko, Jae-Sub ; Chung, Dong-Hwa ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1555~1562
This paper presents a cooling system using thermoelectron for improving the output of BIPV module. The temperature characteristic in regard to improving the output of BIPV system has rarely been studied up to now but some researchers only presented the method using a ventilator. The cooling system efficiency of BIPV module applied to a ventilator mainly depends on the weather such as wind, insolation etc. Because the cooling system of BIPV module using a ventilator is so sensitive, that is being set off by wind speed at all time but is unable to operate in the NOCT(Nominal Operating Cell Temperature) which is able to make the maximum output. The paper presents the cooling system using thermoelectron so as to solve such problems. The temperature control of thermoelectron can be controlled independently in the outside environment because that is performed by micro-controller. The temperature control of thermoelectron, also, can be operated around NOCT through algorism of the temperature control. Therefore, outputs of the whole system increase and the efficiency rises. The paper demonstrates the validity of proposed method by comparing the data obtained through a experiment of the cooling method of BIPV using a ventilator and proposed thermoelectron.
Dynamics Modeling of Polymer Electrolyte Membrane Fuel Cell (PEMFC) for Optimal Design of Power Conditioning System (PCS)
Kim, Jong-Soo ; Choe, Gyu-Yeong ; Kang, Hyun-Soo ; Lee, Byoung-Kuk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1563~1571
In this paper, dynamics modeling of a PEMFC is performed by electro-chemical equations. The developed PEMFC simulation model is implemented using MATLAB Simulink in order to design an optimal PCS for fuel cell systems. In addition, by use of the developed model as an input source of PCS, the validity of the proposed dynamic characteristic model of the PEMFC is verified by various simulation and experimental results.
Structural and Dielectric Properties of Epoxy-Organoclay Nanocomposites using Power Ultrasonic Dispersion
Park, Jae-Jun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1572~1578
The effect of the organoclay_10A nanoparticles on the DSC and Structural and Dielectrics Properties(1Hz-1MHz) for epoxy/Organoclay_10A Nanocomposites has been studied. Dielectric properties of epoxy-Organoclay nanocomposites were investigated at 1, 3, 5, 7, 9 filler concentration by weight. Epoxy nanocomposites samples were prepared with good dispersion of layered silicate using power ultrasonic method in the particles. As structural analysis, the interlayer spacing have decreased with filled nanoparticles contents increase using power ultrasonic dispersion. The maximum increase interlayered spacing was observed to decease for above 5wt% clay loading. The other hand, as decrease with concentration filler of the layered silicate were increased dispersion degree of nanoparticles in the matrix. The interesting dielectric properties for epoxy based nanocomposites systems are attributed to the large volume fraction of interfacesin the bulk of the material and the ensuring interactions between the charged nanoparticle surface and the epoxy chains.
Analysis on the Discharge Characteristics of AC Plasma Display Panel with Counter Sustain Electrodes
Bae, Hyun-Sook ; Whang, Ki-Woong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1579~1583
We proposed the new structure of ac plasma display panel(PDP) to improve the luminous efficacy and driving voltage characteristics. Through two-dimensional numerical simulations, we analyzed the effects of new counter discharge type, which consists of counter sustain electrodes and auxiliary electrodes. Generally, an advantage of AC PDP with the counter sustain electrodes has been known for the driving characteristics of the low voltage. In this work, the new counter structure using the ignition discharge by the auxiliary pulse applied to the address electrode showed the result of the increased luminous efficacy. The short gap discharge between two auxiliary electrodes on the front plate could intensity the long gap discharge between counter electrodes. The reliability of simulation result could be confirmed by the experimental result in the test panel.
The Design of Path Length Controller in Ring Laser Gyroscope for Attitude Control in the LEO satellite
Kim, Eui-Chan ; Lee, Heung-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1584~1588
The Ring Laser Gyroscope makes use of the Sagnac effect within a resonant ring cavity of a He-Ne laser and has more accuracy than the other gyros. The Low Earth Orbit satellite for observatory use require the high accuracy Gyro to control and determine the altitude because of the need of payload pointing accuracy. In this paper, The theory of the Path Length Control is explained. The electrical design of Path Length Controller is described. The Design for Path Length Controller is composed of the demodulator, integrator, phase shifter, high voltage amplifier. We apply the circuit to 28cm square ring laser gyro and get the test results.
On-Line Assessment of High Voltage Motor Condition using the Motor Performance Monitor
Kim, Hee-Dong ; Kong, Tae-Sik ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1589~1593
The condition of a high voltage motor was monitored with the motor performance monitor (MPM) at the motor control center. The MPM detected defects in the rotor bar and end ring and input power according to motor and load conditions. The assessment of the condition of a coal pulverizer motor indicated it was clearly in good condition in terms of the rotor bars, over voltage, and motor performance. However, the side bands at frequency, 56.48 Hz indicated existence of rotor end-ring fault. The large torque ripple indicated abnormal operating conditions. After visual inspection, it has been observed that an impeller blade of the circulating water pump was broken off causing the irregular torque pattern.
Effective Ionic Wind Generation of a Surface Discharge Type Ionic Air Pump
Jung, Jae-Seung ; Moon, Jae-Duk ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1594~1598
The ionic air pump can be used towards the thermal management of micro-electronic devices, since the size of pump can be reduced to micrometer orders. In addition, an air pump allows air flow control and generation with low noise and no moving parts. These ideal characteristics of the pump give rise to variety applications. However, all of these applications would benefit from maximizing the flow velocities of the pumps. In this study a surface discharge type air pump, with a third electrode, has been investigated by focusing on elevating the wind velocity and efficiency. As a result, the enhanced ionic wind velocity could be obtained with the third electrode of the proposed air pump.
The co-effect of
, Cu and Ni Powders for Enhancing the Hydrogen Generation Efficiency using Plasma Technology
Park, Jae-Yoon ; Kim, Jong-Suk ; Jung, Jang-Gun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1599~1605
The research was conducted in order to improve the hydrogen generation efficiency of the electrical plasma technology from tap water by using
photocatalyst, mixed Cu -
powder, and mixed Ni -
powder as the catalysts. Experiments were performed with the pulsed power and nitrogen carrier gas. The result has shown that the hydrogen concentration with the presence of
powder was created higher than that of without using photocatalyst. The hydrogen concentration with using
was 3012ppm corresponding to the applied voltage of 16kV, while it without using the
was 1464ppm at the same condition . The effect of
powder was strongly detected at the applied voltages of 15kV and 16kV. This phenomena might be resulted from the co-effect of the pulsed power discharge and the activated state of
photocatalyst. The co-effect of the mixed catalysts such as Cu-
(the mixed photocatalyst
and transition metals) were also investigated. The experimental results showed that, Cu and Ni powder dopants were greatly enhancing the activity of the
photocatalyst. Under these experimental conditions the extremely high hydrogen concentrations at the optimal point were produced as 4089ppm and 6630ppm, respectively.
The Characteristics of UV Generation and Aging Materials in According to Surface Discharge
Shong, Kil-Mok ; Bang, Sun-Bae ; Kim, Chong-Min ; Kim, Young-Seok ; Jung, Jin-Su ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1606~1611
Recently, The diagnosis techniques of electric facilities are developed on live line. This paper describes the discharge characteristics of polymer insulator(EPDM A type). Keeping the facilities in good working order, the goal of this paper will provide the information to enable user to easily judge conditions of facilities on the spot. The performance of polymer insulator is assessed from the KS C IEC 60270 and CEA LWIWG-01(96)(Tracking Wheel Test). As the results, UV generation patterns of polymer insulator grow like a jellyfish shape follow the ramping voltage. Discharging UVs are detected at about 31.25% of breakdown voltage. Just then, dimension of UV image is about
. The dimension of max. UV image is about
. The position of UV generation due to surface discharge of polymer insulator is the center of insulator in the early, then moved the ground side and the last, UV image moved through the junction part of source side. Surface of aged polymer insulator is cracked and faded due to arc. UV absorption spectrum of polymer insulator are appeared the C-H bond of scissoring vib. at
and C=O bond of recombination structure. Also, recombined UV absorption peak such as C-H, N-H, and O-H is detected at the
. Through the paper, there are inspection data which are the relations between surface discharge of polymer insulator and UV detecting image.
Disturbance Observer Design for a Non-minimum Phase System That Is Stabilizable via PID Control
Son, Young-Ik ; Kim, Sung-Jong ; Jeong, Goo-Jong ; Shim, Hyung-Bo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1612~1617
Since most disturbance observer (DOB) approaches have been limited to minimum-phase systems (or systems having no zero dynamics), we propose a new DOB structure that can be applied to non-minimum phase systems. The new structure features an additional system, which is called as V-filter, whose role is to yield a minimum phase system when connected with the plant in parallel. In order to design the V-filter systematically we first consider a class of linear systems that can be stabilized via PID controller. By inverting the controller's transfer function, we can simply construct the filter. A convenient way of designing V-filter is presented by using an iterative linear matrix inequality (LMI) algorithm. With an illustrative example the simulation result shows that substantial improvement in the performance has been achieved compared with the control system without the DOB.
The Design of IMC-PID Controller Considering a Phase Scaling Factor
Kim, Chang-Hyun ; Lim, Dong-Kyun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1618~1623
In this paper, a new design method for IMC-PID that adds a phase scaling factor of system identifications to the standard IMC-PID controller as a control parameter is proposed. Based on analytically derived frequency properties such as gain and phase margins, this tuning rule is an optimal control method determining the optimum values of controlling factors to minimize the cost function, integral error criterion of the step response in time domain, in the constraints of design parameters to guarantee qualified frequency design specifications. The proposed controller improves existing single-parameter design methods of IMC-PID in the inflexibility problem to be able to consider various design specifications. Its effectiveness is examined by a simulation example, where a comparison of the performances obtained with the proposed tuning rule and with other common tuning rules is shown.
PID Controller Design for an Attraction Type Magnetic Levitation System
Kim, Seog-Joo ; Kim, Chun-Kyung ; Kwon, Soon-Man ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1624~1627
This paper deals with a linear matrix inequality (LMI) approach to the design of a PID controller for an attraction type magnetic levitation system. First, we convert the
PID controller problem into a static output feedback problem. We then solve the static output problem by using the recently developed penalty function method. Numerical experiments show the effectiveness of the proposed algorithm.
Dynamic Boundary Tracking Control in Active Sensor Network
Jang, Seyong ; Lee, Giroung ; Song, Bongsob ; Chwa, Dongkyoung ; Hong, Sukkyo ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1628~1635
In this paper, the motion coordination algorithm of mobile agents in active sensor network is proposed to track the dynamic boundary for environmental monitoring. While most of dynamic boundary tracking algorithms in the literature were studied under the assumption that the boundary and/or its evolving rate is known a priori, the proposed algorithm is assumed that the individual active agent can measure the state of environment locally without any information of the boundary. When the boundary is evolving dynamically, the formation of active agents is designed to achieve two objectives. One is to track boundary layer based on the measured information and a small deviation. The other is to maintain a uniform distance between adjacent agents. The algorithm structure based on a state diagram is proposed to achieve these two objectives. Finally, it will be shown in the simulations that all given agents converge to a desired boundary layer and maintain a formation along the boundary. (e.g., a circle, an ellipse, a triangle and a rectangle)
A New Approach to Adaptive HFC-based GAs: Comparative Study on Crossover Genetic Operator
Kim, Gil-Sung ; Choi, Jeoung-Nae ; Oh, Sung-Kwun ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1636~1641
In this study, we introduce a new approach to Parallel Genetic Algorithms (PGA) which combines AHFCGA with crossover operator. As to crossover operators, we use three types of the crossover operators such as modified simple crossover(MSX), arithmetic crossover(AX), and Unimodal Normal Distribution Crossover(UNDX) for real coding. The AHFC model is given as an extended and adaptive version of HFC for parameter optimization. The migration topology of AHFC is composed of sub-populations(demes), the admission threshold levels, and admission buffer for the deme of each threshold level through succesive evolution process. In particular, UNDX is mean-centric crossover operator using multiple parents, and generates offsprings obeying a normal distribution around the center of parents. By using test functions having multimodality and/or epistasis, which are commonly used in the study of function parameter optimization, Experimental results show that AHFCGA can produce more preferable output performance result when compared to HFCGA and RCGA.
T-S Fuzzy Modeling of Synchronous Generator in a Power System
Lee, Hee-Jin ; Baek, Seung-Mook ; Park, Jung-Wook ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1642~1651
The dynamic behavior of power systems is affected by the interactions between linear and nonlinear components. To analyze those complicated power systems, the linear approaches have been widely used so far. Especially, a synchronous generator has been designed by using linear models and traditional techniques. However, due to its wide operating range, complex dynamics, transient performances, and its nonlinearities, it cannot be accurately modeled as linear methods based on small-signal analysis. This paper describes an application of the Takaki-Sugeno (T-S) fuzzy method to model the synchronous generator in a single-machine infinite bus (SMIB) system. The T-S fuzzy model can provide a highly nonlinear functional relation with a comparatively small number of fuzzy rules. The simulation results show that the proposed T-S fuzzy modeling captures all dynamic characteristics for the synchronous generator, which are exactly same as those by the conventional modeling method.
Design of High Speed Encryption/Decryption Hardware for Block Cipher ARIA
Ha, Seong-Ju ; Lee, Chong-Ho ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1652~1659
With the increase of huge amount of data in network systems, ultimate high-speed network has become an essential requirement. In such systems, the encryption and decryption process for security becomes a bottle-neck. For this reason, the need of hardware implementation is strongly emphasized. In this study, a mixed inner and outer round pipelining architecture is introduced to achieve high speed performance of ARIA hardware. Multiplexers are used to control the lengths of rounds for 3 types of keys. Merging of encryption module and key initialization module increases the area efficiency. The proposed hardware architecture is implemented on reconfigurable hardware, Xilinx Virtex2-pro. The hardware architecture in this study shows that the area occupied 6437 slices and 128 BRAMs, and it is translated to throughput of 24.6Gbit/s with a maximum clock frequency of 192.9MHz.
The Study of Complex RF Unit in WiBro Base Station for Wave 2 Standard
Choi, DooHun ; Moon, Yon-Tae ; Kim, Do-Gyun ; Choi, Young-Wan ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1660~1668
The WiBro was adopted to the 3G international standard. By the change of specification from Wave 1 to Wave 2, MIMO technology is applied in order to increase the speed of downlink. By MIMO the RF part of WiBro base station is increased to 2 Tx paths. Therefore, the size of RF part is bigger and material cost is increased. For reducing these demerits, the RF part which is consisted of PA, LNA, and TDD switch is designed to one complex RF unit. Also, the experimental results of the RF unit have been discussed. Since the complex RF unit is more compact than the RF part of Wave 1 base station, it can be used as the RF part of Wave 2 base station with 2T/2R MIMO.
Pedaling Characteristics of Cycle Ergometer Using the MR Rotary Brake
Yoon, Y.I. ; Kwon, T.K. ; Kim, D.W. ; Kim, J.J. ; Kim, N.G. ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1669~1673
A new cycle ergometer using a Magneto-Rheological (MR) rotary brake system has been developed for rehabilitation of hemiplegia patients to reduce uneven pedaling characteristics. For this purpose, a control method to adjust the resistance of the MR rotary brake in real time based on the magnitude of the muscular force exerted by the subject has been devised so that the mechanical resistance to the pedaling can be minimized when the affected leg was engaged for pedaling. A series of experiments were carried out with and without the engagement of this real-time control mode of MR rotary brake at different pedaling rate to find out the effect of the real-time control mode. The characteristics of the pedaling for these specific conditions were analyzed based on the variations in angular velocities of the pedal unit. The results showed that the variations in the angular velocities were decreased by 42.9% with the control mode. The asymmetry of pedaling between dominant and non-dominant leg was 19.63% in non-control mode and 1.97% in the control mode. The characteristics of electromyography(EMG) in the lower limbs were also measured. The observation showed that Integrated EMG(IEMG) reduced with the control mode. Therefore, the new bicycle system using MR brake with the real time control of mechanical resistance was found to be effective in recovering the normal pedaling pattern by reducing unbalanced pedaling characteristics caused by disparity of muscular strength between affected and unaffected leg.
Age-related difference of the 15 Characteristics Variables in Surface EMG Signals Generated Under Constant Load Contraction
Lee, Jin ; Yoo, In-Gyu ; Kim, Se-Dong ;
The Transactions of The Korean Institute of Electrical Engineers, volume 57, issue 9, 2008, Pages 1674~1680
The objective of this study is to compare age-related differences of 15 characteristic variables estimated from SEMG signals, which were obtained from the old group(62 subjects) and young group(72 subjects). The SEMG signals were recorded from biceps brachii muscle under sustained isometric elbow flexion contraction with constant load(4kg dumbbell) during 30 seconds. Ten time domain (ARV, RMS, MSA, MTA, ZC, MSF, MTF, MSD, MTD, MSS) and five frequency domain(MNF, MDF,
) variables were extracted from the SEMG signals and then statistically analyzed, respectively. The findings of the analysis indicate significant age-related differences in the SEMG signal during constant load contraction.