• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.100-100
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• 2015

자연유역은 주어진 강우에 대해 다양한 형태의 유출반응을 나타내는데, 이는 순간반응함수(Instantaneous Response Function; IRF)로 표현될 수 있다. IRF는 유역의 DEM(Digital Elevation Model)으로부터 지표수 흐름방향을 추출한 뒤 지형분석을 통하여 구한 인자를 이용해 구하는 것이 일반적인 이론이다. 여기서 DEM의 모든 셀에 대해 흐름방향을 부여할 수 있지만, 모든 셀이 하천에 해당하지는 않는다. 따라서 최상류의 셀들은 사면으로, 하류의 셀은 하천으로 구분하여 IRF모의에 적용하게 된다. 사면과 하천은 지표수이송에 전혀 다른 경향을 보이므로 전체적인 유역의 유출반응에 큰 영향을 미친다. 예를 들어 사면과 하천에서의 유속 차이는 IRF의 왜도(skewness)에 주된 영향을 미치는 것으로 알려져 있다 (Botter and Rinaldo, 2003). 하지만, DEM에서 사면과 하천을 정확하게 구분하는 것은 매우 어렵기 때문에 하천시점을 정의하는 데에는 불확실성이 내재되어 있으며, 이러한 점은 추정된 IRF의 불확실성으로 연결된다. 본 연구에서는 하천시점의 불확실성으로 인한 IRF의 불확실성을 정량화하고, 그것의 유의수준을 평가하고자 한다. 이를 위해 다양한 유원면적 기준에 대해 IRF를 계산하고, 그 결과를 심도 있게 고찰한다.

• Korean Journal of Crystallography
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• v.9 no.2
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• pp.125-130
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• 1998

본 논문에서는 부직포를 삽입한 Gr/Ep 복합재료의 충격 흡수 특성을 연구하였다. 계면(interface) 층에 유리 부직포 또는 탄소 부직포를 삽입하여 복합적층판을 제작하였다. 저속충격 시험을 수행하였으며, 충격에 의한 층간분리(delamination)를 C-Scan과 현미경을 사용하여 관찰하였다. 실험결과 계면에 부직포를 삽입함으로써 충격에 의한 층간분리 면적이 감소함을 알 수 있었다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.115-126
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• 2019

Recently, in order to solve the traffic congestion in urban areas and to improve the peripheral environment, research on the design and construction technology development of great depth underground double-deck tunnel is under way by using the underground space in the urban area. The network type double-deck tunnel is in the form of an intersection with a small cross section and a steep slope as per construction at the base of a flatland, so that the fire smoke spreads rapidly in case of fire, which is expected to cause damage of human life. Therefore, this study is analyzed the delay effect of fire smoke diffusion according to the installation and non - installation of delay system for fire smoke diffusion at the intersection. Fire fumes were delayed up to 270 seconds when the delay system for fire smoke diffusion was installed at the intersection and it is analyzed that the greater the operating area of the delay system for fire smoke diffusion, the more preventable the damage of human life of the intersection.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.12
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• pp.1653-1658
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• 2018

This study aims to analyze the cases of VR space to improve the regulations. The space is divided according to the multi-use business act when the VR simulator and the VR game are simultaneously installed in a single space. It is necessary to amend the rules of the Tourism Promotion Act so that it can operate at a certain area of the youth game room subject to the Game Industry Law. Amendments that do not compartmentalize a space partition in the Multi-use Business Act should be carried out simultaneously. This is safer alternative by collective management rather than by the safety applied within a limited space by eliminating the compartment by industry. This is a legal amendment that allows VR simulator and VR game to be operated in the same space even in small sized amusement facilities such as other amusement facilities. This regulatory improvement plan is expected to help the activation of small sized VR theme parks.

• Composites Research
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• v.25 no.5
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• pp.147-153
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• 2012

In this paper, static perforation tests are conducted to predict the penetration energy for the composite laminates subjected to high velocity impact. Three methods are used to analyze the perforation energy accurately. The first method is to select the perforation point using the AE sensor signal energy, the second method is to retest the tested specimen and use the difference between initial and retested perforation energy, and the third method is to select the perforation point based on the maximum loading point in the retested load-displacement curve of the tested specimen. The predicted perforation energy results are presented and verified by comparing with those by the high velocity tests.

• Composites Research
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• v.26 no.1
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• pp.21-28
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• 2013

The ballistic limit of Carbon/Epoxy composite laminates with the finite effective area are predicted by using the quasi-static perforation test and semi-empirical formula. The perforation energy were calculated from force-displacement curve in quasi-static perforation test. Also, the actual ballistic limit and penetration energy were obtained through the high-velocity impact test. The quasi-static perforation test and high-velocity impact test were conducted for the specimens with 3 different effective areas. In the high-velocity impact test, the air gun impact tester were used, and the ballistic and residual velocity was measured. The required inputs for the semi-empirical formula were determined by the quasi-static perforation tests and high-velocity impact tests. The comparison between semi-empirical formula and high-velocity impact test results were conducted and examined. The ballistic limits predicted by semi-empirical formula were agreed well with high-velocity impact test results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3184-3190
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• 2013

These days, the great part of design processes in the field of ship or offshore manufacturing are planed and implemented using the customized CAD system for each ship-building companies. It means that all information for design and production could be extracted and reused at the useful other area cost considerable time and efforts. The representative example is the estimation of welding length and material amount which is demanded during the construction of ship or offshore structures. The proper estimation of welding material to be used and the usage of them at the stage of schedule planning is mostly important to achieve the seamless process of production and expect the costing in advance. This study is related to the calculation of welding length and needed material amount at the stage of design complete utilizing the CAD system. The calculated amount are classified according to welding position, stage, block, bevel and welding type. Moreover it is possible to predict the working time for welding operation and could be used efficiently for the cost management using the results of this research.

• The KIPS Transactions:PartB
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• v.11B no.1
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• pp.27-34
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• 2004

This paper proposes a method to trace and interpret a moving object based on the information which can be directly obtained from MPEG-2 compressed video stream without decoding process. In the proposed method, the motion flow is constructed from the motion vectors included in compressed video. We calculate the amount of pan, tilt, and zoom associated with camera operations using generalized Hough transform. The local object motion can be extracted from the motion flow after the compensation with the parameters related to the global camera motion. Initially, a moving object to be traced is designated by user via bounding box. After then automatic tracking Is performed based on the accumulated motion flows according to the area contributions. Also, in order to reduce the cumulative tracking error, the object area is reshaped in the first I-frame of a GOP by matching the DCT coefficients. The proposed method can improve the computation speed because the information can be directly obtained from the MPEG-2 compressed video, but the object boundary is limited by macro-blocks rather than pixels. Also, the proposed method is proper for approximate object tracking rather than accurate tracing of an object because of limited information available in the compressed video data.