• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.497-504
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• 2000

This paper presents a method for the equivalent-circuit parameters and torque characteristics calculation of squirrel-cage induction motors. The measurment of motor parameters were calculated by the stator resistance test, the blocked rotor test and no load test through T type equivalent-circuit method. Especially, this paper describes the test results obtained by using hall sensor and strain gage for the current and the torque characteristics of induction motors. 1(HP), three-phase squirrel cage induction motor has been used during the test and the parameters are compared with those obtained by the maker parameters of simulation results and experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.257-264
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• 2013

The purpose of this study was to examine the weight bearing exercise effect on bone mineral density(BMD) and upper extremity function in the female stroke patients. The subject were 24 female stroke patients, randomly assigned to a weight-bearing group(n=12, WBG) and a control group(n=12, CG). The experiments were conducted for three times per week for eight weeks, radial BMD and MFT(Manual Function Test) of both groups were measured before the experiments and eight weeks after the beginning of the experiments. In conclusion, it was found that there was a significant increase of the weight-bearing group radial BMD and MFT score, The results suggest that weight bearing exercise is effective in improving BMD and upper extremity function, thus, can be utilized in stroke rehabilitation.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.487-491
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• 2008

Tuning of the speed controller in the linear servo applications needs the accurate information of a mover mass including a load mass. Therefore this paper proposes the mass estimation method of a permanent magnet linear synchronous motor(PMLSM) applied at the vertical axis by using the recursive Least-Squares estimation algorithm. First, this paper derives the deterministic autoregressive moving average(DARMA) model of the mechanical dynamic system used at the vertical axis. The application of the Least-Squares algorithm to the derived DARMA model gives the mass estimation method. Matlab/Simulink-based simulation and experimental results show that the total mover mass of a PMLSM applied at the vertical axis can be accurately estimated at both no-load and load conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.34-42
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• 2000

In this paper conventional technique will be described, which can be used for the measuring various parameters of induction motor. This is followed by presenting some other, alternative, techniques. The two tests are described which are suitable to obtain the electrical parameters of symmetrical 1hp three-phase squirrel-cage induction motor. These are the blocked rotor test and no load test. By the application of these, it is possible to determine the parameters which are presented in the steady-state equivalent-circuit of determining an induction motor. One conventional method of determining the inertia of an induction motors is obtained by performing retardation tests. The angular rotor speed of the motor is monitored, following its disconnection from the stator supply. Since the inertia torque J dw/dt contains the inertia coefficient J and the friction and windage torque Bw contains the coefficient B, then J and B can be determined by performing retardation tests.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.4
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• pp.371-378
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• 2015

Range extenders, which are power generation systems driven by small engines, extend the driving distance and time of electric vehicles (EVs) through continuous charging of batteries. The currently used range extenders with gasoline engines pose limitations with regard to the realization of high-power compact systems, owing to their complex structure and low energy density. In contrast, micro gas turbine (MGT) range extenders (MGT power packs) possess high power and low weight, and can therefore be significantly reduced in size despite increase in speed. In this study, an MGT power pack for the range extenders of EVs was developed using a turbo-prop micro turbine, an alternator for passenger vehicles and electric batteries. The operating characteristics of the MGT power pack were measured through a series of experiments conducted under electrical no-load and load conditions. Their power generation performance and efficiency were measured under various electrical loads and power transmission gear ratios. From the results, electrical load was found to have no influence on power generation performance. The maximum electrical power output was 0.8 kW at a core turbine speed of 150 krpm, and the application of 3:1 reduction gear to the turbine output shaft increased the power to 1.5 kW by 88%. This implies that the test results demonstrated stable power generation performance of the MGT power pack regardless of vehicle load changes, thus revealing its feasibility for use with the range extenders of EVs.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.51-53
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• 2003

본 논문에서는 압전 트랜스듀서의 임피던스 해석을 유한 요소법을 통해 실험적으로 검증하였고 이러한 유한 요소법을 이용하여 압전 변압기의 동작 주파수 및 등가회로 정수를 도출하였다. 또한, 등가 회로법을 이용하여 부하 변동에 따른 압전 변압기의 공진 주파수와 효율 변화를 분석하고 이를 실험적으로 검증하였다. 한편, 유한 요소법과 자동 요소 분할 프로그램(Auto-Mesh Generator), 최적화 알고리즘을 이용하여 일정 부하에서 최대 효율과 승압비를 갖는 압전 변압기의 형상 최적화를 수행하였는데, 최적화 기법으로는 sinc함수의 수렴 결과를 통해 타당성이 입증된 진화 알고리즘(Evolution Strategy)을 적용하였다.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.819-821
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• 2003

본 논문에서는 압전 트랜스듀서의 임피던스 해석을 유한 요소법을 통해 실험적으로 검증하였고, 이러한 유한 요소법을 이용하여 압전 변압기의 동작 주파수 및 등가회로 정수를 도출하였다. 또한, 등가 회로법을 이용하여 부하 변동에 따른 압전 변압기의 공진 주파수와 효율 변화를 분석하고 이를 실험적으로 검증하였다. 한편, 유한 요소법과 자동 요소 분할 프로그램(Auto-Mesh Generator), 최적화 알고리즘을 이용하여 일정 부하에서 최대 효율을 갖는 압전 변압기의 형상 최적화를 수행하였는데, 최적화 기법으로는 sinc 함수의 수렴 결과를 통해 타당성이 입증된 진화 알고리즘 (Evolution Strategy)을 적용하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.379-382
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• 2011

Engine test as well as unload test of starting motor itself was performed to evaluate the braking characteristics of starting system used for initial spin-up of gas turbine for power generation. Through the experimental evaluation of the braking performance with the capacity of braking resistor of the starting motor, we have achieved quantitative data to secure robust braking characteristics in emergency during the starting period of the gas turbine. It is possible to establish a capacity selection criterion of braking resistor to ensure the starting reliability of the gas turbine.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.317-323
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• 2006

The objective of this study is to test and modify the gantry travel mechanism of an ALV(automated lifting vehicle) as a main technology of development of ALV. For the purpose of the improvement of container terminal productivity, this study performed to develop the ALV as a part of R&D. In order to verify the design data and detect the errors of detailed drawings, we performed the various limited weight test under load and unload conditions. Through the reflect of final drawing based on the this test, we could use to produce the more complete vehicle.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.534-542
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• 2005

This paper proposes the fuzzy logic based vector control method for a Surface Mounted Permanent Magnet Synchronous Motor(SMPMSM) used in the elevators. The gain of a conventional PI speed controller in the elevator drive system can not be usually set high due to mechanical resonances, therefore its performance becomes deteriorated. There have been many methods to solve above problems such as an acceleration feedback in the speed controller. However, the above methods have defects that parameter information is demanded. In this paper', a Fuzzy controller(FC) is adopted in the elevator drive system. The performance of a fuzzy controller is compared with a PI controller in the no load and load conditions by simulation and experiments.