• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.93-96
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• 2009

Foundation structure for the main engine heavy spare parts in the engine room is susceptible to resonance problem due to outfitting weight. In addition the deck floor has a large opening for the main engine installation and maintenance, which further weakens the foundation structure. To reinforce the weak structure, two types of approaches have been used; 1) insert an H-pillar below or above the floor and 2) increase the stiffener size. In this paper, the H-pillar approach is used to solve the vibration problem of the foundation structure in the engine room opening area. A commercial program is used to analyze the vibration problem ad to find the location and the size of the H-pillar. Modal test at the quay and on-board vibration measurement during the sea trial have confirmed the validity of inserting an H-pillar below the floor.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.3
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• pp.409-428
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• 1995

Job shop scheduling with m different machines and n different jobs is a NP-hard problem of combinatorial optimization. The purpose of the paper is to develop the heuristic method using tabu search for job shop scheduling to minimize makespan or mean flowtime. To apply tabu search to job shop scheduling problem, in this paper we propose the several move methods that employ insert moves in order to generate the neighbor solutions, and present the efficient rescheduling procedure that yields active schedule for a changed operation sequence by a move of operations. We also discuss the tabu search techniques of diversifying the search of solution space as well as the simple tabu search. By experiments, we find the appropriate tabu list size and tabu attributes, and analyze the proposed tabu search techniques with respect to the quality of solutions and the efforts of computation. The experimental results show that the proposed tabu search techniques using long-term memory function have the ability to search a good solution, and are more efficient in the mean flowtime minimization problem than in the makespan minimization.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.109-121
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• 2009

As our society is changed to the information & digital society based on the internet, the requirement that the analog certificate of Korean residence is changed to digital one is increased. The Korean Government selected the smart card of 72 KB for the digital certificate of Korean residence and try to insert the personnel information of 41 items to it. The method that the numerous personnel information is stored in one smart card is convenience to use. If the certificate of residence is lost, the number of personnel information is misused or spreaded thorough the Internet by the hacking. In this paper, we analyze the problem about the digital certificate of Korean residence and propose the countermeasure about the problem. In the proposal, the digital certificate of residence have only the certificate. Therefore, the size of the smart card is minimized and can be canceled at the loss of the certificate of residence. And the exposure worry of personnel information will be decreased.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.61-64
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• 2001

Delta-integration vectors were constructed for the purpose of achieving homologous integration of the hirudin expression cassette into the chromosome of Saccharomyces cerevisiae. A double $\delta$ system truncated with the unnecessary bacterial genes, and consequently having a reduced insert size for integration, showed a four-fold increase in transformation efficiency at given DNA concentrations, and as a result, the constructed recombinant yeast strain had a 1.3-fold enhancement in hirudin expression level compared with a single $\delta$ system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.237-240
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• 2004

Indexable end mills, which consist of inserts and cutter body, have been widely used in roughing of parts in the mold industry. The geometry and distribution of inserts on cutter body are determined by application. This paper proposes analytical cutting force model for indexable flat end-milling process. Developed cutting force model uses the cutting-condition-independent cutting force coefficients and considers runout, cutter deflection and size effect for the accurate cutting force prediction. Unlike solid type endmill, the tool geometry of indexable endmill is variable according to the axial position due to the geometry and distribution of inserts on the cutter body. Thus, adaptive algorithm that calculates tool geometry data at arbitrary axial position was developed. Then number of flute, angular position of flute, and uncutchip thickness are calculated. Finally, presented model was validated through some experiments with aluminum workpiece.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.419-426
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• 2011

In this study, an experimental and theoretical program were carried out to determine the cutting forces and chip formation at different cutting speeds using a 0.4mm nose radius ceramic insert and -7 rake angle for non heat-treated AISI 4140 (27HRc) and heat-treated AISI 4140 (45 HRc) steel. The results obtained were compared to show the hardness differences between the materials. The secondary deformation zone thicknesses when comparing the two materials show different physical structure but similar size. These results were also discussed in light of the heat treatment and the effects it had on the machining characteristics of the material. In addition, the Oxley Machining Theory was used to predict the cutting forces for these materials and a comparison made. The predicted cutting performances were verified experimentally and showed good agreement with experimental data.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.40-42
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• 2015

최근 UHD TV 시장이 커지면서 이에 따라 4K 이상의 해상도에 대응하는 코덱의 필요성이 증가하였다. 2013년 1월 차세대 동영상 압축 기술인 HEVC (High Efficiency Video Coding)가 제정되면서 초고해상도 동영상에 대응이 가능해졌다. 새로운 동영상 압축 기술이 제정되면서 초고해상도 동영상에서도 워터마킹의 필요성이 증대되었다. 본 논문에서는 PU 크기와 모드의 상관관계를 이용하여 압축 시 인트라 프레임에서 워터마킹 삽입영역을 제시한다. 또한 이를 바탕으로 간단한 워터마킹 삽입 방법 알고리즘을 소개한다.

• Proceedings of the KIEE Conference
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• 2006.05a
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• pp.37-40
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• 2006

This paper presents the evaluation electric shock risk In bath so that we made and designed a bathtub which is the same size in real public bath. and then we did an experiment, provided of electric leakage in various conditions so, we measured how to form an electric potential and knew the electric potential is formed variously under exposed conductor in bath. also we made certain that electric shock risk is down if we insert an insulated pipe in bathtub pipe which is prevent from being formed the electric field sharply.

• Journal of Korea Foundry Society
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• v.20 no.3
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• pp.188-196
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• 2000

A vacuum casting was proposed as a new fabrication method of Si wafer for solar cell substrate. It was tried to fabricate a Si plate with good properties and to reduce the production cost by direct vacuum casting. By $5{\sim}10$ cmHg of pressure difference Si plate with $50{\times}46{\times}1.5\;mm^3$ was fabricated. For the preventing of the reaction between graphite mold and Si melt, BN powder coating or BN insert were used. The Si wafer was poly crystalline with 100 ${\mu}m{\sim}1$ mm order of grain size. And there were some twins and dislocations in the grains.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.325-333
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• 2001

The effect of base metal grain size on isothermal solidification behavior of Ni-base superalloy, CMSX-2 during transient liquid phase (TLP) bonding was investigated employing MBF-80 insert metal. TLP-bonding of single crystal. coarse-grained and fine-grained CMSX-2 was carried out at 1373∼1548k for various holding time in vacuum. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process for single crystal, coarse-grained and fine-grained base metals. The completion time for isothermal solidification decreased in the order ; single crystal, coarse-grained and fine-grained base metals. The difference of isothermal solidification rates produced when bonding the different base metals could be explained quantitatively by the effect of base metal grain boundaries on the apparent average diffusion coefficient of boron in CMSX-2.