• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1122-1123
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• 2008

This paper proposes a the high efficiency tracking system regarding power loss when operating a tracking system for environment variable such as a rapidly changing insolation and shadow effect to improve the power of PV tracking system. To reduce the power loss, this paper proposes a novel control algorithm of the tracking system. And paper suggests a method controlling an altitude for length which is received the shadow influence of PV array. The paper is analyzed efficiency about conventional PV tracking method, comparing proposed algorithm with high performance method.

• Journal of Society of Preventive Korean Medicine
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• v.8 no.2
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• pp.1-12
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• 2004

This paper estimated the demand and supply of physicians for oriental medicine for the period of $2009{\sim}2019$. Two equation models were used in the estimation of manpower. In 2004, the total number of physicians of oriental medicine was amounted to 13,662 registered and 10,532 available in clinical practice, respectively. According to estimates in the study, overall excess supply of physician manpower in oriental medicine was expected in the period, such as $5,300{\sim}5,700$ persons in 2009 and $900{\sim}1,700$ persons in 2019. However, the excess supply would be mitigated after 2019 mainly due to an increase in demand for oriental medical services. Specially, opening medical service market to overseas could be an exogenous variable in physician supply. An alternative manpower policy for oriental medical doctors is needed in a way of controlling oversupply.

• The Journal of Korea Robotics Society
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• v.2 no.2
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• pp.168-177
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• 2007

In a number of fields, robots are being used for two purposes: efficiency and safety. Most robots, however, have single-actuator mechanism for each joint, where the tasks are performed with high stiffness. High stiffness causes undesired problems to the environment and robots. This study proposes redundant actuator mechanism as an alternative idea to cope with these problems. In this paper, Double-Actuator Unit (DAU) is implemented at each joint for applications of multi-link manipulators. The DAU is composed of two motors: the positioning actuator and the stiffness modulator, which enables independent control of positioning and compliance. A three-link manipulator with DAUs enables adaptive control of RCC. By modulating the joint stiffness of the manipulator and controlling the position of RCC, we can significantly reduce contact force during assembly tasks and surgical procedures.

• Journal of the Korea Furniture Society
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• v.12 no.2
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• pp.73-80
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• 2001

The purpose of human factor study is to help the people in good conditions, and to increase the efficiency of physical productivity and mental creativity Also for the furniture design field, the applications of human scale dimensions are considered as the very important aspects. For the design of the office systems furniture, designer must consider the onveniences of variable users as much as possible. To design the office systems for the various work environment, it is necessary to analyze the human scale dimensions according to the furniture items and the user behaviors. In these days, many countries are interested about the workplace ergonomic regulations to reduce a class of injuries called ‘Musculoskeletal Disorders(MSDs)’ by controlling risk factors. In this study, I intend to research and to analyze the features of human scale dimensions and the user behaviors of office environment, and propose some office furniture design tips.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.11
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• pp.535-540
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• 2003

Since axial flux motor has an advantage over more conventional radial flux type motor such as high power density, it can be used as a power train for hybrid electric vehicle and electric vehicle. Also operating range can be extended and efficiency can be improved by changing air gap. Optimal operating air gap is estimated based on the measured efficiency at different air gap. Motor model is developed based on estimated optimal air gap and efficiency. Motor/controller performance is analyzed through simulation. Possible application area of axial flux motor was explored through simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.34
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• pp.173-183
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• 1995

Life cycle cost has been one of the key criteria in design or purchasing of systems, particularly in the flying weapon system. Unexpected cost increase or system breakdown during the system life can be reduced by controlling maintenance cost A system should be designed for maintainability in early stage of product life cycle. The design should be insensitive to its environmental, organizational, and human factors in the stage of customer's utilization. This paper presents LCC as a controllable variable and also suggests a new control model for LCC analysis. The estimation of maintenance cost based upon maintenance scenario, design of maintainability followed by minimizing maintainability loss function in the beginning stage of design, and increase of useful life of systems are among the factors to control LCC.

• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.38-45
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• 2008

The application of the electric propulsion system to the vessels has recently become common due to the latest technology for controlling the electric motors with variable speed. However it has been found that harmonic distortion exists in the electric propulsion system, which consists of an electric motor, a converter and an inverter, and this harmonic distortion has a harmful effect on the system. In this paper, the definition of the harmonic distortion and problems caused by the harmonic distortion in the electric propulsion of the vessels are introduced and the practical solutions for the problems are investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.5
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• pp.313-320
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• 2001

In the present study, various experiments were performed to investigate capacity modulation and refrigerant flow distribution of a multi-heat pump using a variable speed compressor and electronic expansion valves(EEVs) in the cooling mode. Based on the experimental results, it was possible to understand the interrelation of dual indoor units which provides some difficulties in capacity control of each indoor unit. The characteristics of capacity modulation of two indoor units were measured by controlling two EEVs with a cooling load of each indoor unit.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.191-194
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• 2009

Very big springback in advanced high strength steel(AHSS) sheets invokes undesired shape defects, which can be eliminated by the tool surface correction method or the forming process control method. Since the springback reduction by controlling the forming process is limited, in this study, the die correction method which finds die correction from the relationship between die design variable and springback is introduced to achieve springback reduction and is applied to the automotive side rail to reduce the springback of 75.8% within the assembly limit of 1 mm.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.11
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• pp.866-875
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• 1991

In this paper, multi pulse excited-linear predictive coding (MPE-LPC), where the correlation eliminated residual signal is modeled by a few pules, is shown to be effective for the compression of electrocardiogram (ECG) data, and a more efficient scheme for a faithful reconstruction of ECG is proposed. The reconstruction charateristic of QRS's and P.T waves is improved using the adaptive pulse allocation (APA), and the compression ratio (CR) can be changed by controlling the mumber of modeling pulses. The performance of the proposed method was evaluated using 10 normal and 10 abnormal ECG data. The proposed method had a better performance than the variable threshold amplitude zone time epoch coding (AZTEC) algorithm and the scan-along polygonal approximation (SAPA) algorithm with the same CR. With the CR in kthe range of 8:1 to 14:1, we could compress ECG data efficiently.