• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.61-64
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• 2004

The strength characteristics as well as deformation behaviors of honeycomb sandwich composite (HSC) structures were investigated under bending in consideration of various failure modes such as skin layer yielding, interface-delamination, core shear deformation and local buckling. Deformation behaviors of honeycomb sandwich plates were observed with various types of aluminum honeycomb core and skin layer. Their finite-element analysis simulation with a real model of honeycomb core was performed to analyze stresses and deformation behaviors of honeycomb sandwich plates. Its results were very comparable to the experimental ones. Consequently, the increase in skin layer thickness and in cell size of honeycomb core had dominant effects on the strength and deformation behaviors of honeycomb sandwich composites.

• Korean Journal of Pharmacognosy
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• v.7 no.2
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• pp.119-121
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• 1976

To investigate untoward effects which might be produced by local application of Ginseng saponin, sensitization test and eye irritation test were performed in guinea pigs and rabbits. Any reaction on the skin was not found at a dose of 0.1ml of 0.1% solution in sensitization test. Instillation of Ginseng saponin (0.1ml of 1.0% and 10% soultion) into the right eye of rabbits, did not produce any irritation. Median lethal dose of the total saponin in mouse was 695 mg/kg by i.p. and 1490mg/kg by s.c. injection.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.316-318
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• 2002

멀티캐스트를 처리하기 위해서는 멀티캐스트 라우팅과 신뢰성 있는 전송을 위한 기법이 필요하다. 신뢰성 있는 전송에서는 손실된 패킷에 대한 재전송을 하며 이때 재전송 버퍼에 패킷들을 저장하고 있어야만 재전송이 가능하므로 얼마만큼의 패킷을 재전송을 위해 저장하고 있을 것인가 하는 문제가 있을 수 있다. 이 문제를 해결하기 위해 본 논문에서는 멀티캐스트 트리 상의 응답자와 수신자들 사이의 NAK를 이용해서 얻어진 타이머 값을 기준으로 하여 적정량의 버퍼만을 유지하고 상황 변화에 동적으로 대응할 수 있는 TBM (Timer-based Buffer Management) 기법을 제안하며, 실험을 통하여 오류가 발생하는 환경이나 망의 크기 등에 상관없이 버퍼를 능동적으로 관리하는 것을 보인다.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.424-442
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• 2005

In this paper a design of a large shield Tunnel through weathered soil and weathered rock in 703 section of seoul subway line No.7 extension project is presented. The geological investigation results show that the projecet region consists mostly of weathered soil with some local weathered rock in the tunnel excavation level. A EPB shield TBM is selected as a optimal excavation machine for the large shield Tunnel considering the geological and site conditions. Also, the shield machine head and cutter for the large shield tunnel type are designed considering site geological conditions and average advance rate in similar projects.

• Nuclear Engineering and Technology
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• v.8 no.1
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• pp.41-47
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• 1976

A nondestructive, instrumental neutron activation analysis using a Ge(Li) detector is applied to investigate the present levels of mercury and other trace elements in some fresh-water fish. The results show large variations of mercury content which are indicative of important local sources and indicate the inter-dependence relations between two of some trace elements. Analytical results for mercury in antracites are also given with the concern for their combustion as one of major causes of the mercury pollution.

• Korean journal of communication and information
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• v.27
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• pp.283-316
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• 2004

This study examines different news frames of local newspapers reporting the controversial 'Nu[lear Waste Site' issues which deeply split regions showing their intention to bid for the state affair. Three local papers were analyzed for this study, "Gwang-Ju-Il-bo" "Mae-il-sin-mun" and "Jun-buk-il-bo." Overall, the three local papers displayed widely divergent main news frames on the same issue. Firstly, "Gwang-Ju-Il-bo", and "Mae-il-sln-mun" showed the strong tendency of using 'counter frame' while "Jun-buk-il-bo" exhibited 'loral development frame'. Secondly, "Gwang-Ju-Il-bo", and "Mae-il-sin-mun" were frequently headlined 'Nuclear Waste Site', while "Jun-buk-il-bo" carried headlines 'Radioactive Waste Management Facility' overwhelmingly more often than the other two papers, indicating that headline key words are closely associated with the configuration of news frames. Thirdly, the main news frames remained consistent for "Gwang-Ju-Il-bo", and "Mae-il-sin-mun" even after the government's report about the possible connection of 'ion-beam irradiation-accelator' and 'Nuclear Waste Site.' On the other hand, "Jun-buk-il-bo" was significantly less headlined 'Nuclear Waste Site' while significantly more headlined "Radioactice Waste Management Facility." "Jun-Buk-il-bo" which is in stark contrast to the other two papers changed in its tone by increasing the 'local development frame' with decrease in the 'counter frame.' The "Jun-buk-il-bo"'s more frequent use of 'Radioactive Waste Management Facility' as a headline than "Nuclear Waste Management Equipment" is seen as its attempt to minimize negative image of Nuclear Waste and to promote favorable public opinion by highlighting aspects of economic benefits and the local development the construction would brind about. The major findings of this study further support the claim that media overage ends up a reality. The fact that Buan in Jun-buk Province made a successful bid for the construction is not a coincidence.

• Composites Research
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• v.18 no.1
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• pp.30-37
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• 2005

The bending strength characteristics and local deformation behaviors of honeycomb sandwich composites were investigated using three-point bending experiment and finite element simulation with a real model of honeycomb core. Two kinds of cell sizes of honeycomb core, two kinds of skin layer thicknesses, perfect bonding specimen as well as initial delamination specimen were used for analysis of stress and deformation behaviors of honeycomb sandwich beams. Various failure modes such as skin layer yielding, interfacial delamination, core shear deformation and local buckling were considered. Its simulation results were very comparable to the experimental ones. Consequently, cell size of honeycomb core and skin layer thickness had dominant effects on the bending strength and deformation behaviors of honeycomb sandwich composites. Specimens of large core cell size and thin skin layer showed that bending strength decreased by $30\~68\%$.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.56-63
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• 2009

Resource reservation scheme is effective for better QoS guarantee to handover call for the next generation cellular systems where handover rate highly increases. However, resource reservation for handover call can incur negative impact on the new user admission. In this paper, we propose a random access based adaptive group-wise reservation to effectively reduce dropping rate of handover call, while protecting new local call. In the proposed scheme, target base station divides adaptively future handover users into groups based on the expected handover time, and then does group-wise reservation, where service allocation within each group is done on random access basis. Markov approach is also provided to analyze the performance of the proposed scheme. By computer simulation, it is shown that theoretical analysis on the performance is similar to the simulation results and the proposed reservation scheme outperforms the conventional scheme with respect to dropping probability of handover call.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.4
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• pp.89-99
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• 2008

In Korea, currently 10 local governments have completed the construction of the 3D Land Geospatial Information, since the pilot project started in 2004 and many other local governments are additionally constructing the 3D Land Geospatial Information. Technical Guidance for the 3D Land Geospatial Information has made out the construction methodology and concept of the ordinances in 2006 by the basis of the research results of the pilot project for the 3D Geospatial Information construction in 2005. But the result that applied the existing 3D Land Geospatial Information of the local governments, many problems rearing up on the methods and expression accuracy of the 3D Land Geospatial Information. This research analyzed and derived problems of established guideline for the zero-defects construction of the 3D Land Geospatial Information and it is aim at the present standardized criterion of the reestablished and method of the 3D Geospatial Information construction items. Improvement scheme of the 3D Land Geospatial Information is considered to be contribute to the standardized good quality of 3D Land Geospatial Information construction and its application.

• Journal of the Korean Magnetics Society
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• v.23 no.3
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• pp.110-116
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• 2013

This paper proposes a sampling-based sensitivity method for dealing with electromagnetic coupled design problems effectively. The black-box modeling technique is basically applied to obtain an optimum regardless of how strong the electromagnetic, thermal and structural analyses are coupled with each other. To achieve this, Kriging surrogate models are produced in a hyper-cubic local window with the center of a current design point. Then design sensitivity values are extracted from the differentiation of basis functions which consist of the models. The proposed method falls under a hybrid optimization method which takes advantages of the sampling-based and the sensitivity-based methods. Owing to the aforementioned feature, the method can be applied even to electromagnetic problems of which the material properties are strongly coupled with thermal or structural outputs. To examine the accuracy and validity of the proposed method, a strongly nonlinear mathematical example and a coil design problem for local induction heating are tested.