• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.203-222
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• 2011

The characteristics of flood damages have been increasingly strengthened and take the form of unpredictable and unusual weather phenomena caused by climate change and climate anomalies. To prevent inundation damage caused by breach of hydraulic structure such as dam or levee, and trouble of drainage of inner basin, the prediction necessity of flood inundation area, flood risk analysis, and drawing flood risk maps have been on the rise, and the national flood risk maps have been produced. In this study, the quantitative flood vulnerability analysis was performed, which represents population living within flood-affected areas, types of economic activities, facilities affected by flood, in order to extend flood risk mapping from simple hazard concept into risk based idea. By applying it to Nakdong River basin, the flood vulnerability indices were estimated to draw flood risk maps subdivided into administrative districts. The result of this study can be applied to establish the disaster prevention measures and priority decision of disaster prevention project.

• Journal of the Korean Geotechnical Society
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• v.20 no.5
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• pp.87-98
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• 2004

In this study reinforcing effect of soil nailed-drilled shafts subjected to axial and lateral loads was evaluated. Special attention was given to the reinforcing effects of soil nails placed from the drilled shafts to surrounding weathered- and soft-rocks based on model tests, numerical analyses and field tests. The model tests and numerical analyses are conducted to analyze the reinforcing effect of various conditions of number, inclination, position and length. The results of 1/40 scale model tests and numerical analyses show that as the number of reinforcing level increases, the incremental effect of reinforcement tends to increase, whereas the reinforcing effect on relative position is negligible. In addition there is a reinforcing effect as the inclination angle increase up to 30 degrees. Based on the results of tensile load tests, soil nailed-drilled shaft has a considerably smaller settlement to reach the ultimate level compared with the result of un-reinforced drilled shafts. For compression tests, there is a reinforcing effect of about 200% measured.

• Journal of Oral Medicine and Pain
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• v.35 no.4
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• pp.293-298
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• 2010

The goal of this study is to contribute to the clinical application by making a quantitative nerve current perception threshold(CPT) examination for the evaluation of numbness that could be occurred after dental surgery, Measurement of CPTs at each different frequencies(2000 Hz, 250 Hz, and 5 Hz) were performed to trigeminal nerve main branch(mandibular division) of 29 patients with dental surgery on mandibular area and 25 normal subjects. There were significant differences in CPTs between patient group and control group.(p<0.05) But, there were no significant between patient male and female in both patient and control group except 2000 Hz was significantly high in the control female.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.5
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• pp.406-418
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• 2004

Last days, various kinds of applications and system were individually introduced into specific groups or enterprises by different objective without considering interoperability among those. However, the environment for data processing is changing rapidly in these days. And now the necessity is growing to integrate and couple applications and system in the process dimension for more flexible and quicker data processing on these application programs and system. When integrating these application programs or system, an integration based on XML is recommended as it is one of good methods which will the additional cost and satisfy the requirements of the integration. This is because the XML is not only device-independent data type which can be used any platform, but also it uses XSLT, the document conversion standard established by W3C, which allows easy data conversion from one to another type on occasion of demands. This paper studies a design and implementation of system to convert XML structure. This system shows the structure of source- side providing data and destination-side processing data with using XML schema that defines structural information of a XML document. And this system defines the structure relationship of desired form as mapping structural information and data. This system creates the XSLT document that defines conversion rule between two structures based information which is defined. The XSLT document which is created as described above will convert data to be appropriate to the structure of the destination- side. By implementing this system, it is able to apply a document into various kinds of structure without considering specific system or platform and it is able to construct XSLT document to which meaning of desired form can be given. This paper aims to offer a process conversion between documents and to improve interoperability and scalability, so that we can contribute to build XML document processing environment

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.55-55
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• 2011

연안 및 해안공학의 발달과 더불어 부유식방파제의 기능적 효율성이 중요시 되고 있다. 흔히 사용되어오던 착저식방파제는 설치에 많은 시간과 경비가 소요되고 환경 및 생태계에 많은 변화를 줄 수 있으며, 설치 예정지의 수리학적 특성 등의 여건에 많은 제약을 받는 단점이 있다. 부유식방파제는 일본 등의 선진국을 중심으로 활용이 잦아지고 있는 방파제로서 수면 위에 설치되기 때문에 수중 생태계에 미치는 영향이 적은 친환경방파제이다. 또한 기존에 시공된 중력식방파제와는 달리 수심에 제한을 덜 받고, 공사기간이 짧기 때문에 경제적이다. 실제 시공사례로는 2007년 마산 원전항에 완공된 부유식방파제가 대표적이며, 지금까지도 부유식방파제에 대한 여러 연구자들의 관심이 증가하고 있는 추세이다. 방파제뿐만 아니라 우리나라처럼 국토의 면적이 작은 지역에서 증가하는 해상물동량을 소화하기 위해서 부유식방파제 등을 이용한 항만의 시공이 필요한 실정이다. 이러한 부유식방파제의 분석적인 측면에 있어서 수치해석은 파랑과 구조물의 상호작용을 해석하는 데 한계가 있으며, 부유식방파제 단면형상을 정확하게 재현할 수 없으므로, 수리모형실험을 통한 부유식방파제의 연구가 필요할 것으로 판단된다. 최근 기술의 발달로 인한 유동장 해명이 가능해 졌으며, PIV(Particle image velocimetry) 및 LDV시스템은 다양한 분야에서 응용되고 있다. 특히, LDV시스템은 측정하려는 한 지점에 대하여 레이저 빔을 단면(Cross-section)으로 만들고 입자의 산란광을 후방산란(Back scatter)으로 받아서 도플러 효과를 이용, 속도에 대한 주파수를 획득하며, 유속을 측정하는 장비로 매우 높은 정확도와 비접촉식 이라는 장점을 가지고 있다. 또한, PIV 시스템에 비하여 측정시간이 오래 걸리는 반면 데이터를 가공하지 않고 활용할 만큼 높은 정확성을 가지고 있다. 본 연구에서는 수리모형실험을 통하여 단독형, 2열형 및 3열형 부유식방파제의 형상, 흘수 및 거리를 변화시키며 유동장을 수집하였으며, 방파성능에 따른 와의 생성 및 소멸시점에서의 파랑변형과의 관계를 분석하였다. 방파제의 형상과 흘수를 달리하여 수리모형실험을 수행하였으며, 와류의 상관관계를 분석하였다. 또한, 연직 2차원 Navier-Stokes 방정식 모형을 이용하여 수치모형실험을 수행하였으며, 수치모형실험 결과와 수리모형실험 결과를 비교 분석하였다. 후방방파제에서 발생되는 파랑은 입사파의 주기가 길어질수록 상대적으로 커지는 현상을 보였으며, 흘수심이 깊어질수록 전방방파제 입사 면에서 자유 수면이 높게 관측되는 결과를 보였다. 또한, 비교적 장주기파랑에 해당하는 입사파랑의 경우 전달파고비 산정에 있어서 설계기준인 0.5를 대다수 초과하는 반면, 3열형 구조에서는 대부분이 0.5이하로 상당히 높은 방파성능 결과를 나타내었다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.375-392
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• 2018

The shield TBM method is widely adopted for tunneling works in urban area because it has more beneficial ways to control settlement at ground surface than conventional mined tunneling. In the shield tunneling, backfill grouting at tail void is crucial because it is supposed not only to restraint ground deformation around tail void during excavation but also to compensate precedent ground settlement by pushing up the ground with highly pressurized grout. However, the tail void grouting has been found to be ineffective for settlement compensation particularly in sandy ground, which might be caused by complicate interaction between ground and tail void grouting. In this paper, the effects of tail void grouting on behavior of ground in shield TBM tunneling were investigated based on 3-dimensional finite element analyses. The results of numerical analyses indicated that backfill grouting actually reduces settlement by degrading settlement increasing rate in excavation, which means decrease of volume loss. Meanwhile, the grouting could not contribute to compensate the precedent settlement, because reduction of volume loss by grouting was found to be counterbalanced by volume change of ground.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.5
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• pp.245-256
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• 2002

Shadows are important elements in producing a realistic image. Generation of exact shapes and positions of shadows is essential in rendering since it provides users with visual cues on the scene. It is also very important to be able to create soft shadows resulted from area light sources since they increase the visual realism drastically. In spite of their importance. the existing shadow generation algorithms still have some problems in producing realistic shadows in real-time. While image-based rendering techniques can often be effective1y applied to real-time shadow generation, such techniques usually demand so large memory space for storing preprocessed shadow maps. An effective compression method can help in reducing memory requirement, only at the additional decoding costs. In this paper, we propose a new image-barred shadow generation method based on image warping. With this method, it is possible to generate realistic shadows using only small sizes of pre-generated shadow maps, and is easy to extend to soft shadow generation. Our method will be efficiently used for generating realistic scenes in many real-time applications such as 3D games and virtual reality systems.

• The KIPS Transactions:PartA
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• v.16A no.6
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• pp.427-436
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• 2009

Digital virtual manufacturing is a technology that aims for the rapid development of products and the verification of production-process in ways that are more efficient by integrating digital models within the entire manufacturing process. These digital models utilize various information technologies, such as 3D CAD and simulations. Mixed reality, which represents graphical objects for only needed parts against real scene, can bring a more enriched sense of reality to an existing virtual manufacturing system that is in a pure virtual environment, and it can reduce the time and money needed for modeling the environment. This paper suggests a method for planning virtual factory layouts based on mixed reality using legacy datathat are already constructed in the real field. To do this, we developed the method to acquire simulation data from legacy data and process this acquired data for visualization based on mixed reality. And then we construct display system based on mixed reality, which can simulate virtual factory layout with processed data. Developed system can reduce errors related with factory layout by verifying the location and application of equipments in advance before arrangement of real ones at the practical job site.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.769-782
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• 2009

Stereoscopic video service is one of the most widely adopted technologies for 3-Dimensional technology. However, the stereoscopic video service has not been penetrated into the market since there does not exist a proper transmission method even though the conventional MPEG-2 Transport Stream (TS) has support for broadcast service of mono-scopic video contents. This is partly because the MPEG-2 TS does not support displaying a stereoscopic video content which consists of several composition types widely used in the market. This paper proposes the new MPEG-2 TS specification suitable for transmitting and displaying stereoscopic video contents. In order to show feasibility of the proposal, this paper describes an end-to-end system which is implemented with consideration of the method how to multiplex and de-multiplex stereoscopic video contents as well as keeping backward compatibility with the traditional MPEG-2 TS.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.275-289
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• 2018

It is necessary to develop a bridgehead port for trading with northern countries to promote trade through the East Sea because the East Sea Rim economic bloc around the Northeast Asia including South Korea, China, Russia, Japan, and North Korea has a high growth potential in the future. Therefore, this study aims to suggest a strategic direction to enhance the competitiveness of Donghae Port through reinforcement of container cargoes by conducting Importance-Performance Analysis (IPA) for stakeholders of Donghae Port. The analysis results suggest that it is necessary to improve the five evaluation factors: attractiveness of container and bulk volumes, appropriate ratio of export/import container quantities, frequency of vessel entry and diversity of sea routes, convenience of complex linked transportation, and competitiveness of cargo handling equipment. The implications of this study are as follows. First, it is necessary to continuously research the current status of container and bulk cargo volumes of the port and ways to increase the absolute cargo volume. Second, we need to consider realistic alternatives to improve the ratio of export/import container quantities. Third, in terms of network, we should establish a service improvement plan to increase the frequency of port calls and the diversity of sea routes. Furthermore, incentives should be provided to increase the trade volume of Donghae Port through strengthened complex linked transportation function. Finally, it is urgently necessary to provide investment support for container handling equipment as an essential requirement for the activation of the container cargoes in Donghae Port.