• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.239-246
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• 2004

The fixed ends beam is analyzed by the s d 0 f system with the rigid-plastic model. And the safety criteria of the fixed ends beam to the Impulsive loads are established with the peak-load ratio to the static collapse load and impulse ratio to the ideal impulse producing the critical displacement. It is shown that the impulse and the peak-load of the impulsive loads are the important factors for the damage of the structures. It is also shown that the damage curves with the peak-load and impulse ratio are useful method to estimate the damage of the structures due to the emphasis on the equivalent dynamic loads rather than the equivalent static loads in the process of deriving the curve.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.1
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• pp.157-164
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• 2004

The safety criteria for the simple beam with a rigid-plastic model under the impulsive loadings are established with the peak-load ratio to the static collapse load and impulse ratio to the ideal impulse producing the plastic hinge at the mid-span. It is shown that the impulse and peak-load of the impulsive loadings are the important factors for the damage of the structures. It is also shown that the damage curves with the peak-load and impulse ratio may be useful method to estimate the damage of the structures due to the emphasis on the equivalent dynamic loads rather than the equivalent static loads in the process of deriving the curve.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.90-97
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• 1991

A stepping motor can be driven with open-loop or closed-loop control. The major disadvantage of open-loop control is that it is subjected to resonance and instability in certain speed range, and that there is no way to check stalling or error in position. In this paper, a closed-loop control system consisting of a microcomputer, a hybrid stepping motor, a drive, a lead screw, and an encoder which is used as a position sensor is developed. A control program is programmed in assembly language for real time control and the versatile interface adapter(VIA) is used as the interface with the microcomputer. The experimental results of the stepping motor were eliminated on all kinds of inertia load, and maximum start stop pulse rate and maximum slewing pulse rate were also increased about twice respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.7
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• pp.1314-1320
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• 2001

DC motors have widely been used in the field of variable-speed driving system since it is easy to control flux and torque of the motors precisely but it is hard to check and maintain those periodically. In addition, there are difficulties in high power and high speed running due to rectifying limit of commutator, and are a lot of restrictions in installation. Therefore, speed control in BLDC(Brushless DC) motors have seriously been studied for a long while. In this paper, a mathematical model of BLDC motor driven by PWM inverter is developed. Dynamics and steady-state characteristics of BLDC motor are simulated and analyzed with a series of experiments for the parameter estimation : torque, speed, phase voltage and current.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.408-413
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• 2001

DC motor has widely been used in the field of variable-speed driving unit since it is easy to control flux and torque precisely but it is troublesome to check and maintain periodically. In addition, there are difficulties in hish power and high speed running due to rectifying limit of commutator, and are a lot of restrictions in installation. Therefore, speed control in BLDC(Brushless DC) motor has seriously been studied for a long while. In this paper, a mathematical model of BLDC motor driven by PWM inverter is developed. Dynamics and steady-state characteristics of BLDC motor are simulated and analyzed with a series of experiment for the parameter estimation : torque, speed, phase voltage and current.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.811-813
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• 2005

최근 아동들이 흥미와 이해, 창의적인 교육을 위한 도구로 게임을 주목하고 있다. 그러나 기존의 아동용 게임은 키보드와 마우스 같은 한정된 입력 장치를 사용하고 있어 아동들이 보다 편리하고 용이하게 게임을 즐길 수 있는 인터페이스의 개발이 요구된다. 본 논문에서는 기존의 입력 장치를 손동작을 이용한 실감형 인터페이스로 대치하는 아동용 게임설계를 제안한다. 카메라를 통해 들어온 동영상에서 손동작을 인식 및 추적하고 추적된 손동작의 의미를 기존 입력 장치의 입력 값으로 변경하여 게임의 입력 값으로 전달한다. 본 논문에서는 제안된 손동작 인터페이스를 아동용 게임에 적용시킴으로써 그 효용성을 증명한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.177-182
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• 2010

Research on recovering original images from captions has been widely done in a reusability point of view. In usual, dynamic images imported from foreign countries often have captions of foreign languages, so it is necessary to translate them into one's language. For the natural exchange of captions without loss of original images, recovering the images corresponding to captions is necessary. However, though recovering original images is very important, systematic analysis on the characteristics of captions has not been done yet. Therefore, in this paper, we first survey the classification methods of TV programs at academic worlds, broadcasting stations, and broadcasting organizations, and then analyses the frequency of captions, importance of caption contents, and necessity of recovering according to their types. Also, we analyze the characteristics of captions which are significantly recognized to be necessary to recover, and use them as recovering information.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.1
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• pp.34-43
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• 2000

Replicated data that is used for fault tolerant distributed system requires replica control protocol to maintain data consistency. The one of replica control protocols is quorum consensus method which accesses replicated data by getting majority approval. If site failure or communication link failure occurs and any one can't get quorum consensus, it degrades the availability of data managed by quorum consensus protocol. So it needs for ghost to replace the failed site. Because ghost is not full replica but process which has state information using meta data, it is important to simplify meta data. In order to maintain availability and simplify meta data, we propose a method to use cohort set as ghost's meta data. The proposed method makes it possible to organize meta data in 2N+logN bits and to have higher availability than quorum consensus only with cohort set and dynamic linear voting protocol. Using Markov model we calculate proposed method's availability to analyze availability and compare it with existing protocols.

• Clinics in Shoulder and Elbow
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• v.13 no.1
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• pp.141-145
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• 2010

Purpose: Understanding elbow biomechanics is necessary to understand the pathophysiologic mechanism of elbow injury and to provide a scientific basis for clinical practice. This article provides a summary of key concepts that are relevant to understanding common elbow injuries and their management. Materials and Methods: The biomechanics of the elbow joint can be divided into kinematics, stability and force transmission through the elbow joint. Active and passive stabilizers include bony articular geometry; soft tissues provide joint stability, compression force and motion. Results and Conclusion: Knowledge of elbow biomechanics will help (i) advance surgical procedures and trauma management, (ii) develop new elbow prostheses and (iii) stimulate future research.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.110-114
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• 2004

This paper deals with the dynamic characteristic analysis of linear actuator(LA) considered with coupling of mechanical spring system This application of linear actuator is increasing due to simple mechanical structure, a high efficiency, and a stable motional action. This paper proposed and analyzed the Serial Piston Actuator(SPA) by using mechanical spring system coupled with linear actuator through the simplified structure which was verified practical experiments.