• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1981-1986
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• 2004

In this study, the basic motor control system had been investigated. The controller for this study consists of two main parts, a feedforward controller part and a feedback controller part. Each part will deals with different control problems. The feedback controller deals with robustness and stability, while the feedforward controller deals with response speed. The feedforward controller, used to solve the tracking control problem, is adaptable. To make such a tracking perfect, an adaptive law based on Feedback Error Learning (FEL) is designed so that the feedforward controller becomes an inverse system of the controlled plant. The novelty of FEL method lies in its use of feedback error as a teaching signal for learning the inverse model. The theory in $H^{\infty}$-Control is selected to be applied in the feedback part to guarantee the stability and solve the robust stabilization problems. The simulation of each individual part and the integrated one are taken to clarify the study.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.995-1000
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• 2003

This paper proposes the pedestrian navigation system which deals with subjective information. This system consists of the route setting part and the instruction generation part. The route setting part chooses the route with highest subjective satisfaction degree. The instruction generation part gives users the instructions based on the users' sensuous feeling of distance with linguistic expressions. Fuzzy measures and integrals are applied to the calculation of the satisfaction degree of the route which reflects the users' taste for routes. The instruction generation part has database of users' cognitive distance. Users' cognitive distances are expressed by fuzzy sets that correspond to linguistic terms. The system generates the instructions with linguistic terms which have the highest fitness value for the users' sensuous feeling of distance. This paper also performs subjective experiments in order to confirm the validity of the present system.

• 한국디지털정책학회:학술대회논문집
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• 2004.11a
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• pp.449-453
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• 2004

GIS can be used on almost entire fields of the world, such as the national land management, environmental management, disaster management, enterprise activities, and general lives. GIS is called as an infrastructure of the knowledge information on the cultural society. For insuring the national power on the periods of the unlimited competition, it is very important to establish the national information infrastructure. Purpose of the NGIS project I is to development on living benefits of peoplethrough an efficiency of policy and rationalism of planning. In order to achievement of this purpose, the NGIS project I has been established using the national geographic information base planning. The NGIS project I consists of the master management part, the geographic information part, the technique development part, the standardization part, and the land Information part. These five GIS project parts are operated by four governmental ministers and related institutions, such as minister of transportation and construction, minister of science and technology, minister of information and communication, minister of administrative and home affaires. The NGIS I project is to establishment of the nation spatial information systems, such as various nationwide digital maps, GIS technique development, GIS education, GIS standardization, and GIS researches.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.40
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• pp.107-117
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• 1996

This paper considers the part assignment to workstations in flexible manufactuirng system (FMS). Parts are processed through several workstations according to processing order. The machines of each workstation can do multiple Processing functions. Therefore, a processing of a part can be processed in several workstations, which are non-identical in functional performance. Although a processing of a part can be processed in the multiple workstations, it has to be processed in only one among available several workstations, Parts are transported with unit load by automated guided vehicles (AGVs). The criteria of part assignment is to minimize the maximum value of the processing times of each workstation and the total transport times of vehicles. Model formulation is suggested, and numerical example is shown.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.253-257
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• 2001

This study reveals the sheet metal working with multi-forming type ultra precision process. They require analysis of many kinds of important factors, i.e. theory and practice of metal press working and its phenomena, die structure, machining condition for die making, die material, heat treatment of die components, know-how and so on. In this study, we designed and constructed a multi-forming ultra precision progressive die as a bending and drawing working of multi-stage and performed through the try out for thin sheet metal. This part I of papers related to the analysis of production part and strip process layout design through the metal forming simulation by DEFORM and IDEAS.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.5 no.1
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• pp.13-17
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• 2009

The river water heat source heat pump has the advantage in the performance compared to air source heat pump. In this study, an experimental study on a 2-stage heat pump, which is designed to utilize a river water heat source, were carried out. Generally, a heat pump is designed for maximum capacity rate, but it actually operates at part load condition in most cases. Therefore, an information on the part-load characteristic is very important in view of the system overall performance. In this study, part-load performance tests of a R134a 2-stage compression heat pump were carried out over the river water and supply heating water temperature changes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.8
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• pp.1164-1171
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• 2002

This study analyzed the dependence of part load performance of simple cycle gas turbines on their design performance. Various parametric calculations were carried out to examine effects of design temperature ratio, pressure ratio and component efficiencies using a simplified analysis. In addition, a more practical analysis was done for realistic design conditions with the aid of a comprehensive performance analysis program. The results show that gas turbines with higher design performance exhibit less efficiency degradation during part load operation. The influence of power control method (fuel only centre) and air flow control) on part load performance was examined as well.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.4
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• pp.69-87
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• 2006

This paper proposes an effective approach for the part-machine grouping(PMG) based on the non-binary part-machine incidence matrix in which real manufacturing factors such as the operation sequences with multiple visits to the same machine and production volumes of parts are incorporated and each entry represents actual moves due to different operation sequences. The proposed approach adopts Fuzzy ART neural network to quickly create the Initial part families and their machine cells. A new performance measure to evaluate and compare the goodness of non-binary block diagonal solution is suggested. To enhance the poor solution due to category proliferation inherent to most artificial neural networks, a supplementary procedure reassigning parts and machines is added. To show effectiveness of the proposed approach to large-size PMG problems, a psuedo-replicated clustering procedure is designed. Experimental results with intermediate to large-size data sets show effectiveness of the proposed approach.

• Industrial Engineering and Management Systems
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• v.12 no.1
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• pp.41-45
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• 2013

Age replacement policy is a commonly policy in maintenance management of spare part. It means that a spare part is always replaced at failure or fixed time after its installation, whichever occurs first. An optimal age replacement policy of spare parts concerns with finding the optimal replacement time determined by minimizing the expected cost per unit time. The age of the part was generally assumed to be a random variable in the past literatures, but in many situations, there are few or even no observed data to estimate the probability distribution of part's lifetime. In order to solve this phenomenon, a new uncertain age replacement policy has been proposed recently, in which the age of the part was assumed to be an uncertain variable. This paper discusses the optimal age replacement policies by dealing with the parts' lifetimes as different distributed uncertain variables. Several results on the optimal age replacement time are provided when the lifetimes are described by the uncertain linear, zigzag and lognormal distributions.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.431-436
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• 2005

In this paper, We proposed the stereo image modeling using 2-dimensional images captured by the high resolution cameras to inspect the ball defects of BGA(Ball Grid Array) device. The proposed algorithm consists of the package/ball area extraction part, the FOV(Field of View) calibration part, the top point matching part, and ball height measurement part, In the package/ ball area extraction part, the package and ball areas are separately extracted in a left and right image by the extraction algerian. Through the experiment, we draw out the result.