• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3792-3803
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• 1996

Since the skew beam element has two curvatures which are a curvature and a torsion, spatial behavior of curved beam which cannot be included in one plane can be anlayzed by emploting the skew beam element. The $C^{0}$-continuous skew beam element shows the stiffness locking phenomenon when full integration is employed. The locking phenomenpn is characterized by two typical phenomena ; one is the much smaller displacement thant the exact one and theother is the undelation phenomenon is stress distribution. In this paper, we examine how unmatched coefficient in the constrained energy brings about the locking by Reduced Minimization theory. We perform the numerical ones. These comparisons show that uniformly full integration(UFI), which employs full integration for the constrained energy, entails the locking phenomenon. But the use of uniformly reduced integration(URI) of selectively reduced integration(SRI), which employs reduced integration for constrained energy, does not produce the significant errors of displacements of the undulation phenomenon in stress distribution since they do not entails the locking, Additionally, the error due to the approximated parameters for describing the geometry of skew beam is examined.d.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.99-105
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• 2017

Generally, stereo matching methods are used to estimate depth information based on color and spatial similarity. However, most depth estimation methods suffer from the occlusion region because occlusion regions cause inaccurate depth information. Moreover, they do not consider the temporal dimension when estimating the disparity. In this paper, we propose a temporal stereo matching method, considering occlusion and disregarding inaccurate temporal depth information. First, we apply a global stereo matching algorithm to estimate the depth information, we segment the image to occlusion and non-occlusion regions. After occlusion detection, we fill the occluded region with a reasonable disparity value that are obtained from neighboring pixels of the current pixel. Then, we apply a temporal disparity estimation method using the reliable information. Experimental results show that our method detects more accurate occlusion regions, compared to a conventional method. The proposed method increases the temporal consistency of estimated disparity maps and outperforms per-frame methods in noisy images.

• The KIPS Transactions:PartD
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• v.16D no.2
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• pp.191-200
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• 2009

Location based services (LBSs) have drawn huge attention as the growing number mobile devices and wireless technology demand more pervasive information access. In LBSs, Constraint nearest neighbor queries are one of the important queries of human to fulfill his desired quickly through wireless technology. We propose new query processing of constrained nearest neighbor query on the air to support mobile clients which demand optimal uses of wireless broadcast channel and using minimum battery power of client. First we proposed NN query processing with constrained region and then explain the novel NN query processing with various types of constraints. We have proposed novel algorithms to support Constrained Nearest Neighbor queries on the air based on Distributed Spatial Index and Bitmap-based Spatial Index.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.446-454
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• 2010

CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.20 no.6
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• pp.81-87
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• 2018

In this paper, in order to maximize the input process efficiency of the building energy simulation field, the authors developed the automatic extraction module of spatial information based BIM geometry information. Existing research or software extracts geometry information based on object information, but it can not be used in the field of energy simulation because it is inconsistent with the geometry information of the object constituting the thermal zone of the actual building model. Especially, IFC-based geometry information extraction module is needed to link with other architectural fields from the viewpoint of reuse of building information. The study method is as follows. (1) Grasp the category and attribute information to be extracted for energy simulation and Analyze the IFC structure based on spatial information (2) Design the algorithm for extracting and reprocessing information for energy simulation from IFC file (use programming language Phython) (3) Develop the module that generates a geometry information database based on spatial information using reprocessed information (4) Verify the accuracy of the development module. In this paper, the reprocessed information can be directly used for energy simulation and it can be widely used regardless of the kind of energy simulation software because it is provided in database format. Therefore, it is expected that the energy simulation process efficiency in actual practice can be maximized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.521-524
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• 2014

Because of the development of computers and networks, the use of the internet has been rapidly increased. The smart devices, such as smart phones and tablet PCs, have made an epoch-making changes, which have brought people's daily lives to the cyber world and life values have been improved. The cyber world not only just changed individual's lives, but also affected all areas and the world. The recent global trends reside mainly in protection of energy sources, and nation's dependency of the information system such as politic, economic and national security. Since major national infrastructure becomes a stragic attack target, the importance of cyber warfare has rised as an effective way to attact enermy. This article explores the concept of cyber warfare and national cyber capability, and then figure out the plan of reaction to minimize damages with best protection when cyber warfare occurs.

• Journal of the Korean GEO-environmental Society
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• v.20 no.1
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• pp.35-42
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• 2019

Various development works inevitably increase cutting slopes due to land use, and many of trails managed by different authorities are being deteriorated by long-term weathering. Collapse of slopes causes unavoidable damage of property and loss of lives because of its uncertainty and difficulty in predicting its occurrence. In order to overcome the unavoidability, America, Japan, and several European nations analyze the kinetic energy and moving distance when rocks of upper slope move along the inclined plane, via field tests and computerized interpretation of the test results. Also, they are making efforts to develop measures with which the kinetic energy of the rocks moving along the slope is absorbed and fails to reach to specific structures. However, domestic researches just focus on fragmentary prediction of rockfall using existing programs, and there have been few approaches to identify interpretation methods appropriate for domestic cases or determination of parameters. In this context, we in this study defined rockfall types and affecting factors and analyzed effects of parameters using a general-purpose rockfall simulation program to understand principles of rockfall and to estimate effects of various parameters.

• Journal of the Korean GEO-environmental Society
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• v.23 no.2
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• pp.37-47
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• 2022

Recently, with the establishment of active stabilization measures, large-scale collapse of slopes is decreasing. However, the frequency of rockfalls due to the destabilization of floating stones or boulder within or above the slope has not been decreased significantly. As a measure for stabilizing rockfall and disaster prevention, protection methods such as rockfall barriers and rockfall protection nets are typically applied. However, the approach to catching the rockfall in a catchment area by reducing the energy of the rockfall and changing the rolling condition of the rockfall is relatively insignificant. Therefore, in this study, using a general-purpose rockfall simulation program, the change in the rolling characteristics of rockfall according to the specifications of the ditch installed under the slope was investigated. It is expected that the research results can be used as basic data to determine the specifications of the ditch that can be applied to general roads or trails.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.113-124
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• 2021

Underground environmental infrastructure and energy production facilities, which are recognized as avoidable facilities such as landfills, are emerging as an important social issue due to urbanization and economic growth. In order to safely construct a large-scale plant facility in the underground space, it is necessary to increase the utilization of the limited space layout and minimize unnecessary columns. In this study, the plant modularization method(Pipe Rack Module) was reviewed to solve the problems of work constraints, assembly and demolition, process system interconnection, and maintenance that occur when plant facilities are underground. In addition, plant module analysis was performed by applying various load conditions (earthquake load, device load, earth pressure load, etc.) to improve spatial layout usability and secure structure stability. Based on the analysis results under various boundary condition, the implications regarding the minimum installation interval and module arrangement (draft) of basic modules required for the construction of an underground combined plant were derived.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.367-367
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• 2022

토지이용의 고도화에 따라 비점오염원 부하는 증가하는 추세이며 기후변화에 따른 강우강도 증가 등으로 지표면에 축적된 고농도의 비점오염물질이 하천으로 유출, 수질오염을 가중시키고 있어 비점오염원 관리가 필요하다. LID 기법은 자연적 기작(mechanisms)과 공정(process)을 이용하여 생태계의 물질순환(물순환 포함)과 에너지 흐름이 원활하도록 조성하는 기법으로, 불투수층면에서 발생되는 강우유출수를 관리 가능하다. LID 시설에는 전처리 시설을 두어 초기 고농도의 입자상 물질을 저감시키고, 강우유출수 저류공간을 통한 유출저감, 첨두유량 등을 저감시킨다. 이러한 전처리 시설에는 유기물질 및 영양소의 생물학적 제거를 위한 미생물 서식공간의 제공 등의 역할을 수행하기 위하여 다양한 여재를 적용하고 있다. 본 연구는 비점오염물질 유입이 LID 기법 전처리 시설 내 여재층의 물리·화학적 및 생물학적 환경을 평가하였다. 3개 시설 모두 100%의 불투수층에서 발생되는 강우유출수를 처리하는 LID 시설을 연구대상으로 선정하였으며, 각각의 전처리 시설에는 자갈, 우드칩, 쇄석 등이 적용되어 있다. 퇴적물의 경우 가장 상부에 존재하는 층으로 퇴적물의 오염물질 농도는 2~10.7배 이상 매우 높게 나타났다. 우드칩의 경우 다른 여재에 비해 높은 함수량과 유기물 함량을 보였으며 이는 우드칩의 수분을 보유하는 능력과 거친 표면공극에 오염물질이 부착되기 때문으로 나타났다. 또한, 같은 무기성 여재인 쇄석과 자갈의 경우 여재 크기의 차이를 보임에도 불구하고 미생물의 군집구성과 함수량의 차이를 보이는 것으로 평가되었다. 유기물의 함량이 낮은 강우유출수의 생물학적 처리능력을 향상시키기 위해서는 유기성 여재가 필요하며, 다공성 무기 멀칭재를 적용하고 하부의 토양은 적정 유기물을 배합하여 질산화 및 탈질화 유도가 가능하도록 설계가 필요한 것으로 분석되었다.