• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.5
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• pp.747-755
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• 1990

In this paper, we presented a method of constructing a multiplier and an inverse element generator over finite field GF(3**m). We proposed the multiplication method using a descending order arithmetics of mod F(X) to perform the multiplication and mod F(X) arithmetics at the same time. The proposed multiplier is composed of following parts. 1) multiplication part, 2) data assortment generation part and 5) multiplication processing part. Also the inverse element generator is constructed with following parts. 1) multiplier, 2) group of output registers Rs, 3) multiplication and cube selection gate Gl, 4) Ri term sequential selection part. 5) cube processing part and 6) descending order mod F(X) generation part. Especially, the proposed multiplier and inverse element generator give regularity, expansibility and modularity of circuit design.

• Journal of Applied Reliability
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• v.4 no.2
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• pp.91-104
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• 2004

In this paper we consider the concurrent spare part(CSP) requirements problem of new equipment system. When a part fails, the part is replaced and the repair of failed part is impossible and cannibalization is allowed. We assume that the failure of a part knows a Poisson process. The operational availability concept in CSP is defined, and derive a formula to calculate the operational availability using expected machine operating time during CSP period. A mathematical model is derived for making an CSP requirement determination subject to the constraint of satisfying any given operational availability limitation and an heuristic solution search procedure is derived. An illustrative example is shown to explain the solution procedure.

• Speech Sciences
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• v.7 no.2
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• pp.157-175
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• 2000

The aim of this paper was to diagnose Korean college students' listening skills on the TOEFL. The researchers identified which section, among the TOEFL listening Part A, B, and C, is most easily teachable/ improvable during the period of a semester. First, the result of this research shows that Korean students tend to have lower scores in Part A than Part B or Part C. The results indicate that the short informal conversation doesn't give sufficient clues to students, and they don't have enough time to infer the answer. Second, the results revealed that. students showed the lowest progress in Part B after they studied TOEFL listening items and essential idioms for the listening section for 13 weeks. Because students didn't have much experience learning the informal conversation as opposed to the formal one in English, it is harder to achieve an improved grade in Part B, which consists of the informal conversation. But after a semester-long listening course, the average score on TOEFL listening sections increased.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.35-39
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• 2000

The piercing and blanking of thin sheet metal working is specified division in press die design and making. In order to prevent the detects, the optimum design of the production part, strip process layout, die design, die making and try out etc. are necessary the analysis of effective factors. For example, theory and practice of metal shearing process and its phenomena, die structure, machine tool working for die making, die materials and its heat treatment, metal working in industrial and its know how etc. In this study, we analyzed whole of data base, theoretical back ground of metal working process, and then performed the progressive die tryout with the screw press. This study regards to the aim of small quantity of production parts press working. Part 1 of this study reveals with production part and strip process layout design.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.125-130
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• 1996

This study is concerned with a heuristic algorithm that can make effectively the machine-part grouping in early stage for designing cellular manufacturing systems. By enhancing the Close Neighbour Algorithm(CNA), the proposed algorithm is concerned with making the machine-part grouping that can maximize machine utilization and minimize part's intercell movement by reducing exceptional elements. The algorithm is tested against existing algorithms in solving several machine-part initial matrices extracted from references and obtained by using random number. Test results shows that a solution matrix of the algorithm has superior grouping efficiency to Close Neighbour Algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1614-1617
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• 2003

Actuator being used in the ship supplies engine with air. When actuator is out of order, engine is not operated. This out of order is due to fracture of piston or rotating of spindle in the case of plastic deformation of parallel part in locking plate. For this reason, locking plate must be guaranteed enough strength. Therefor in this paper, the effects of changes with the clearance of between spindle and parallel part, the contact height of parallel part and spindle, the side circle diameter of parallel part and the width of locking plate in the designated torque are investigated. The result of this investigation shows the relation between locking plate and spindle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1840-1843
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• 2003

The Magnetorheological fluid has the properties that its viscosity has drastic changed under some magnetic fields therefore, Magnetorheological fluids has been used for micro polishing of the micro part( for example, a aspherical surface in a micro lens). The polishing process may appears as follows. A part rotating on the spindle is brought into contact with an Magnetorheological finishing(MRF) fluids which is set in motion by the moving wall. In the region where the part and the MRF fluid ate brought into contact, the applied magnetic field creates the conditions necessary for the material removal from the part surface. The material removal takes place in a certain region contacting the surface of the part which can be called the polishing spot or zone. The polishing mechanism of the material removal in the contact zone is considered as a process governed by the particularities of the Bingham flow in the contact zone. Resonable calculated and experimental magnitudes of the material removal rate for glass polishing lends support the validity of the approach.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.4
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• pp.56-62
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• 2006

Various kinds of rapid prototyping processes are available, such as stereo-lithography apparatus(SLA), fused deposition modeling(FDM), selective laser sintering(SLS), 3 dimensional printing(3DP), and laminated object manufacturing(LOM). In this study, benchmark tests are carried out to obtain detailed informations about surface roughness and mechanical properties of those parts. Although the patterns and roughness averages of part surface are dependent on the surface direction, the roughness of SLA part is the best and that of FDM or 3DP part is the worst. It is shown that FDM part has an advantage in impact strength, SLS(or EOS) part in compressive strength, and LOM part has an advantage in tensile strength and heat resistance, but the change of building direction in FDM and LOM processes severely weakens the tensile and impact strengths.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.09a
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• pp.11-18
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• 2002

The Ulsan fault with NNW-SSE strike is a very wide and long lineament about 50km along Gyeungju-Ulsan line in the southeastern part of Korea. According to previous studies the Ulsan fault was not considered as a fault but only long lineament since no displacement was found along the lineament. Recently several Quaternary faults were reported in the northeastern part of lineament, which implies the neotectonic movement in this area. We analysed drainage pattern and stream gradient using the DEM (Digital Elevation Model) data for both side of Ulsan fault line to check the recent topographic changes which indicate neotectonic movement. The result shows that stream index in the eastern part of Ulsan fault is higher than the one in the western part. This means that recent tectonic movement is more active in the eastern part of Ulsan fault.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.3
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• pp.242-250
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• 2003

We propose the monitoring system scheme for the CPS/INS integrated navigation system. The design requirements of the monitoring system are suggested and the software scheme based on GUI is proposed. The proposed monitoring system consists of an I/O interface part, a navigation data display part, and a post-processing part. The I/O interface part is responsible for data communication between the monitoring system and a navigation computer unit. The navigation data display part provides various display methods to show the navigation data to user in real-time. The post-processing part collects the navigation data to analyze the performance of navigation system. The proposed monitoring system software was developed using the Visual C++ programming language and a van test was carried out to demonstrate the real-time operation of the monitoring system. The test result shows that the proposed monitoring system can be effectively applied to the CPS/INS integrated navigation system.