• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.36-42
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• 2007

This paper presents mechanical design, fabrication and test of a biomimetic fish robot actuated by a unimorph piezoceramic actuator, LIPCA(Lightweight Piezo-Composite curved Actuator.) We have designed a linkage mechanism that can convert bending motion of the LIPCA into the caudal fin movement. This linkage system consists of a rack-pinion system and four-bar linkage. Four types of artificial caudal fins that resemble caudal fin shapes of ostraciiform subcarangiform, carangiform, and thunniform fish, respectively, are attached to the posterior part of the robotic fish. The swimming test under 300 $V_{pp}$ input with 0.6 Hz to 1.2 Hz frequency was conducted to investigate effect of tail beat frequency and shape of caudal fin on the swimming speed of the robotic fish. At the frequency of 0.9 Hz, the maximum swimming speeds of 1.632 cm/s, 1.776 cm/s, 1.612 cm/s and 1.51 cm/s were reached for fish robots with ostraciiform, subcarangiform carangiform and thunniform caudal fins, respectively. The Strouhal number, which means the ratio between unsteady force and inertia force, or a measure of thrust efficiency, was calculated in order to examine thrust performance of the present biomimetic fish robot. The calculated Strouhal numbers show that the present robotic fish does not fall into the performance range of a fast swimming robot.

• Journal of Engineering Education Research
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• v.13 no.4
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• pp.93-108
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• 2010

The goal of this study is an analysis on linkage system between in machinery sector. The development of skill framework and national technical qualification items. This paper researched skills and created the skill level through reviewing domestic & foreign documents, interview with experts and in-depth discussions with expert group focusing on terminologies commonly used in the industrial settings. As a result of skill classification, authors were able to classify skills into three categories in medium-scale classification and 11 categories in small-scale classification, and also into total 42 categories through the re-classification of the small-scale classification. The skill level in the area of machine were classified the skill level in the area of machine into 7 level by reflecting the level system of the korean qualification frameworks, qualification and education course, and skill level in the industrial setting. Based on the skill frameworks, we provided definition of skill and skill group, definition of each different skill, and performance standards by skill and level. also, This paper suggests improving measure of national technical qualification items through analysizing linkage situation between skill frameworks & qualification items.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.58-63
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• 2010

A new contact force estimation technique is proposed. Keeping the contact force at a certain level between finishing tool and the object is essential since the quality of the finished surface is very sensitive to the contact force during the finishing process. However, the contact force measurement cannot be obtained by simply installing load cells under machine table or in the middle of tool linkage. The reason is that the weight of the machine table and the tool linkage are much heavier than the force to be measured. To that end, a method for estimating disturbance is proposed for a system that is similar to the mechanism of the finishing machine, and the same method is applied to estimate the contact force of the brush-type finishing machine. To verify the effectiveness of the proposed method, a small scale test set-up has been built and the method has been tested.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.17-20
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• 1996

An adaptive current control scheme of a permanent magnet (PM) synchronous motor with the simultaneous estimation of the magnitude of the flux linkage and stator resistance is proposed. The adaptive parameter estimation is achieved by a model reference adaptive system (MRAS) technique. The adaptive laws are derived by the Popov's hyperstability theory and the positivity concept. The predictive control scheme is employed for the current controller with the estimated parameters. The robustness of the proposed current control scheme is compared with the conventional one through the computer simulations.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.30-32
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• 2004

Complex sensorless control scheme is difficult to utilize in field of home appliance system because of cost problem. Therefore, it is necessary to introduce simplified sensorless control scheme that is composed of least calculation to estimate the rotor position. This paper presents the principle of the rotor position estimation with comparison of the estimated flux linkage and reference flux linkage. In order to verify the feasibility of control scheme, MATLAB is used for simulation.

• Journal of Korean Society of Rural Planning
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• v.23 no.3
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• pp.147-161
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• 2017

Climate changes from global warming and reduction in agricultural land result in volatility of prices of agricultural products, causing a imbalance of food market in Korea. It is necessary to develop a transnational food industry cooperation system among Korea, China and Russia that directly or indirectly affect food industry in terms of the whole industrial network. This study analyzes the value chain and linkage in the agriculture, forestry and fisheries industries in three nations. The unit structure and the industrial patterns of three nations were derived using the World Input-output Table (WIOT) from 2004 to 2014 every five years. This paper is expected to contribute to develop food security cooperation in the northern part of the Korean peninsula and to promote the mutual growth of food industry through industry linkage and cooperation.

• Proceedings of the KIEE Conference
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• summer
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• pp.848-850
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• 2004

Complex sensorless control scheme is difficult to utilize in field of home appliance system because of cost problem. Therefore, it is necessary to introduce simplified sensorless control scheme that is composed of least calculation to estimate the rotor position. This paper presents the principle of the rotor position estimation with comparison of the estimated flux linkage and reference flux linkage. In order to verify the feasibility of control scheme, simulation with MATLAB and experiment is performed.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.74-75
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• 2017

This paper proposes a control scheme of the voltage ripple suppression for the permanent magnet exciter generator. The output voltage of the permanent magnet excitation generator is affected by the field current, load current and the engine speed. The engine speed can be controlled by the governor. But, the actual frequency is changed at the starting and a sudden load variation. As a result, output voltage overshoot and undershoot can decrease the power quality in the grid system. The proposed control scheme uses a frequency factor to control the field current of the generator for the voltage ripple reduction. Because of the linkage flux is proportional to the frequency, the instantaneous frequency can consider the linkage flux. The proposed control method shows the improved control performance for the permanent magnet excitation generator through simulation.

• Journal of Korean Society for Quality Management
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• v.37 no.4
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• pp.43-51
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• 2009

This study was designed to analyze the relationship of process quality, result quality and management performance in Korean insurance industry. For this study the linkage scheme of service quality concept is used on PZB model and BSC(Balances Score Card) system. In the linkage model, the 5 service qualitry factors used in PZB model are used as the result quality variables, and internal process factor, learning/growth factor in BSC are used the process quality variables affecting the result quality variables. And also customer satisfation factor and financial performance index are used as the management performance variables. In the ivsurance industry, the process quality variables were verified to meaningfully affect the result quality variables, and the result service quality variables were verified to affect the management performance indices. As the result, the process quality and the service quality must be emhanced for the competitiveness of Korean insurance industry.

• Asia pacific journal of information systems
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• v.10 no.4
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• pp.21-36
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• 2000

This paper addresses the need to incorporate the increasing trend of partnership formation among business firms into a framework for interorganizational systems. The existing frameworks for classifying interorganizational systems are either conceptually too complex to be readily applicable to IOS planning or too outdated to explain the emergence of numerous forms of global communication networks. Based upon two dimensions, namely value activity linkage and system support level, we propose a new IOS framework which classifies IOS into four types, including (1) operational cooperation, (2) resource pooling, (3) operational coordination, and (4) complementary partnership. We review select cases that fit into each IOS category and draw characteristics of systems of each category. The paper concludes with suggestions for applying the framework to the development of an IOS-enabled corporate strategy.