• Journal of the Society of Naval Architects of Korea
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• v.49 no.4
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• pp.340-349
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• 2012

The mitigation of gap between technology and it's applicability in the oil and gas industry has led to a rapid development of deepwater resources. Historically, subsea wells have good track records. However, an ever increasing water depths and harsher environments being encountered are currently posing challenges to subsea production. Complex subsea systems are now being deployed in ways rarely encountered in previous development schemes. These increasingly complex systems present a number of technical challenges. This study presents the challenges in subsea production systems, considering the technical and safety issues in design and installation associated with current development modality.

• Journal of Welding and Joining
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• v.35 no.1
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• pp.55-60
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• 2017

There are many Industry Code and Standard (ICS) for Structural Integrity Assessment (SIA) on welded structure with defect. The general ICSs, such as R6, BS 7910 and API 579-1/ASME FFS-1, provide equations to determine the upper bound residual stress profiles based on collections from many literatures. However, these residual stress profiles used in the SIA cause the conservative design for welded structures. In this study, the structural integrity assessment for girth weld in pipeline has been conducted based on fracture mechanics. In addition, thermo-elastic plastic FE analysis was performed for evaluating the residual stress of girth weld in pipeline. The weight function solution is used to determine the stress intensity factor using the residual stress profile obtained by the FE analysis. This approach can account for redistribution and relaxation of residual stress as the defects grow. In order to the evaluate quantitative comparison between BS 7910 and weight function solution, structural integrity assessment determining allowable crack size on cracked pipe was performed with failure assessment diagram.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1483-1491
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• 2004

To assess the integrity of the pipeline is the most important problem to be solved first of all for prevention of any fracture accident of the pipeline. As a result of exerting such efforts, a number of plastic collapse assessment equations have been suggested, however, the scope of using or applying such assessment equations has not been exactly defined. In this study, the case that a surface crack existed in the circumferential direction in the external side of the natural gas pipeline and a bending load was applied to the pipeline was analytically identified as the most critical condition, and a plastic collapse assessment equation fur it was suggested. The flow stress of the API X65 linepipe was defined through the experiment conducted on SENT specimens. Also, a local assessing criterion of a 3-dimensional crack behavior considering not only the crack depth but also the crack length was suggested. Finally, a plastic collapse assessment equation for the API X65 linepipe was developed by performing the 3-dimensional finite element analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1386-1389
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• 2008

Conventional viewing angle switching electrode requires pixel division and additional liquid crystal panel. Hence the conventional viewing angle switching has low aperture ratio and high thickness. In this paper we proposed new viewing angle switching using hybrid aligned nematic mode by fringe-field electrode field (named HAN-FFS) with single liquid crystal panel. The fringe-field switching electrode is located at the bottom, and the additional common electrode is located at the top of the cell to control viewing angle. The proposed device is free from additional liquid crystal panel and pixel division. Consequently, the suggested structure has not only high aperture ratio but also show an excellent potential for viewing angle switching.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.340-343
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• 2008

This work reports the simple fabrication of the single cell gap transflective liquid crystal display (LCD) using wire grid polarizer. The nano sized wire grid polarizer was patterned on common electrode itself, on the reflective part of FFS (Fringe field switching) mode whereas the common electrode was unpatterned at transmissive part. However, this structure didn't show single gamma curve, so we further improved the device by patterning the common electrode at transmissive part. As a result, V-T curve of proposed structure shows single gamma curve. Such a device structure is free from in-cell retarder, compensation film and reflector and furthermore it is very thin and easy to fabricate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1054-1057
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• 2003

We have studied $90^{\circ}$ twisted nematic (TN) mode driven by fringe electric field, where two polarizers are parallel each other such that the cell shows a black state before a voltage is applied. According to the studies by computer simulation for a LC with negative dielectric anisotropy, the LC twists perpendicular to the horizontal field direction of fringe electric field and the degree of tilt angle is very low, when a voltage is applied. Therefore, the new device exhibits wide viewing angle characteristic due to in-plane switching and high transmittance since the LC director aligns parallel to the polarizer axis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.109-112
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• 2004

최근들어, TFT LCD 업체들의 제품 대형화에 따라서 서서히 제품군이 중, 대형 TV를 중심으로 넓은 광시야각 기술 (FFS, IPS, VA)이 적용되고 있으며 고휘도, 고속응답, 고색순도 등 성능향상을 지속하는 가운데 LCD 백라이트로써 LCD TV에 적용하기 위해서는 무엇보다도 현재 기존 제품군보다 높은 휘도 특성의 개선이 요구되고 있다. TV 대응 LCD Panel 은 Monitor 대응 제품에 비해서 일반적으로 해상도가 낮으므로, 투과율면에서 장점은 있으나, 현재의 백라이트 구조로는 만족할만한 성능을 낼 수 없는 상황이다. 그러므로 고휘도 백라이트를 위해서 직하방식 백라이트에 대한 개발 검토가 활발히 이루어지고 있다. 따라서 본 연구에서는 백라이트에서 6500nits를 목표로 직하형 백라이트의 시뮬레이션을 실시하였으며, 램프간 거리, 리플렉터와 램프간 거리, 램프와 확산판간 거리등에 해한 최적화를 통하여 총두께에 따른 특성분석을 실시하였다. 특히, 램프의 수량에 따른 휘도 시뮬레이션을 통해서 백라이트별 기구치수를 결정할 수 있었다. 본 연구에서의 목적인 6500nits의 휘도는 프리즘시트의 적용을 통하여 달성하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.337-338
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• 2008

We have studied electro-optic characteristics of a high performance liquid crystal display using Fringe In-plane field Switching (FIS) mode. The strong electric fields cause more liquid crystals to reorient almost in plane above and between the pixel electrodes. As a result, the operation voltage is lower and transmittance is higher than those of Fringe Field Switching (FFS) and In-Plane Switching (IPS) modes. Apparently, the transmittance depends on voltage applied at the configurations of FIS mode which are proposed. Therefore, we have studied certain length of between electrodes for maximum transmittance and light intensity.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.149-156
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• 2003

Recently, the importance of plant maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as riskbased inspection(RBI), fitness for service guidelines(FFS), plant lifecycle management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1933-1940
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• 2003

Recently, the importance of plant maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as risk-based inspection(RBI), fitness for service guidelines(FFS), plant lifecycle management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.