• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.613-625
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• 2012

Since railway bridge frequently have a chance of passing train load close to design load, it is necessary to reflect sufficiently fatigue property in early design phase for many structural details. Nevertheless fatigue cracks are reported partly in deck plate girder of railway steel bridge because of the weight and arrangement of axial load acting on railway bridge, the application of improper structural details for fatigue problem etc.. One of main cause for fatigue crack at the welded part of upper flange and web is caused by the eccentricity action of train load due to the difference of center to center spacing between the main girder supporting sleeper and the rail acting train load. For the existing deck plate girder of railway steel bridge, in this study, field survey, field measurement and a series of structural analysis were performed. In addition, the characteristics of structural behavior, the causes and repair/ retrofit of fatigue crack were examined in the target bridge.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.44-54
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• 2012

In wireless sensor networks, a moving object tracking scheme is one of core technologies for real applications such as environment monitering and enemy moving tracking in military areas. However, no works have been carried out on processing the failure of object tracking in sparse sensor networks with holes. Therefore, the energy consumption in the existing schemes significantly increases due to plenty of failures of moving object tracking. To overcome this problem, we propose a novel moving object tracking scheme based on polynomial regression prediction in sparse sensor networks. The proposed scheme activates the minimum sensor nodes by predicting the trajectory of an object based on polynomial regression analysis. Moreover, in the case of the failure of moving object tracking, it just activates only the boundary nodes of a hole for failure recovery. By doing so, the proposed scheme reduces the energy consumption and ensures the high accuracy for object tracking in the sensor network with holes. To show the superiority of our proposed scheme, we compare it with the existing scheme. Our experimental results show that our proposed scheme reduces about 47% energy consumption for object tracking over the existing scheme and achieves about 91% accuracy of object tracking even in sensor networks with holes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.3
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• pp.219-228
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• 2012

A long-term R&D program for HLW disposal technology development was launched in 1997 in Korea and Korea Reference disposal System(KRS) for spent fuels had been developed. After then, a recycling process for PWR spent fuels to get the reusable material such as uranium or TRU and to reduce the volume of radioactive waste, called Pyro-process, is being developed. This Pyro-process produces several kinds of wastes including metal waste and ceramic waste. In this study, the characteristics of the waste from Pyro-process and the concepts of a disposal container for the wastes were described. Based on these concepts, thermal analyses were carried out to determine a layout of the disposal area of the ceramic wastes which was classified as a high level waste and to develop the disposal system called A-KRS. The location of the final repository for A-KRS is not determined yet, thus to review the potential repository domains, the possible layout in the geological characteristics of KURT facility site was proposed. These results will be used in developing a repository system design and in performing the safety assessment.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.561-572
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• 2002

The objective of this study was to evaluate a feed additives used mainly in lactating cow diets in transient pregrent cow diets. The study was conducted as a completely randomized design with forty Holstein pregnant cows to determine the effect of feeding Aspergillus oryzae(T2), Saccharomyces cerevisiae mixture(T3) and enzyme(cellulase, xylanase) - releasing chemicals(ERC) (T4) on the dry matter intake, milk yield, milk composition and metabolic disorders. Dry matter intake was similar among treatments for 3 weeks prepartum but cows fed enzyme tended to increased feed intake compared to no additives treatment both in calving day and for 3 weeks postpartum. Cows fed Aspergillus oryzae, Saccharomyces cerevisiae and ERC produced more milk than those fed no additives. However, there is no significant difference among treatments. Concentration of glucose was not significantly different among treatment prepartum but that in plasma of cows fed ERC was higher at calving and 3 weeks postpartum compared to others. Increase in NEFA began at 3 weeks prepartum and accelerate during the final 7 days before calving at all treatments but lower for ERC-treated cows at calving and 3 weeks postpartum. Ca concentration not different among treatment prepartum and postpartum. Corticoid content decreased significantly for cows fed ERC compared to those fed non-additives. Metabolic disorder was not occurred in cows fed ERC. However, ketosis and displased abomasum were happened 1 cow when fed non-additives, metritis 1 cow when fed Aspergillus oryzae and retained placenta 1 cow in all treatments except cows fed ERC.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.536-543
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• 2018

In 2003, the local police system was adopted, and the personnel and installation of local police agencies were subsequently changed. According to the "Police Law", local police station shall be established under the control of chief of police department, and the criteria for the installation of local police stations were to take into consideration of population, administrative districts, area, geographical characteristics, traffic and other conditions. The chief of local police has the authority to install district police station according to the "National Police Agency and its Organization". However, it is hard to say they were applied. Futhermore, it is inappropriate to apply the laws and regulations equally across the nation. Also, it has been criticized for its difficulties of patrolling, the weakened relationship with local residents, and poor quality of security services in rural areas. Therefore, this study suggests that the criteria for the installation of the police station should be made through a comprehensive analysis of the characteristics of the areas and security needs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.92-101
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• 2017

The SNS website can take full advantage of the characteristics of users to conduct e-commerce. The e-commerce website's organizing ability will be greatly strengthened by SNS and creates greater value for consumers. This article examined the Chinese largest SNS (Weibo) users as research objects, and combined the development status of SNS in China. This article focuses on the influence to consumer's purchase intention in three aspects: number of comments, consumer involvement level, and consumer appealing method and examines how the interaction of the number of comments and consumer appealing method affects the purchase intention. An investigation was conducted on 400 users of SNS and using valid questionnaires to perform reliability analysis, validity analysis, independent sample t-test, and double factor variance analysis using SPSS21. The research results indicated that the number of comments and rational appealing method had significant effect on the purchase intention. The mediating or controlling the purchase involvement level will disturb the influence of the number of comments but will have no effect on the information appealing method.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.2
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• pp.95-105
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• 2014

Dosangugok is located at Dosan-myeon, Andong City, Gyeongbuk and its original landscape was analyzed based on Valley4 Buncheon among Dosangugok. In order to estimate original landscape of Dosangugok, landscape elements were extracted after investigating ancient literatures including 'Nongamjib' and poetry/prose relevant to Dosangugok, landscape elements that could be confirmed at local site survey were suggested and arrangement of Buncheon village was estimated based on painting works. In analysis of poetry/prose, 29 landscape elements were extracted and as a result of local site survey, 6 places including Jeomam (Jari-bawi), Nongam (Gwimeok-bawi), Sajaseok (Saja-bawi), Sangam (Elephant rock), Dae and Bungang were confirmed to be existed at present and in painting works, Rocks such as Aeildang on the rock adjacent to Bungang, Buncheon Seowon at its backyard village, Bungang Byeoneui Gwimeokbawi, Jeomam were confirmed to be expressed even though not expressed in detail. Survey was performed based on ancient site of Nongam head house in parallel with interview with 17th eldest grandson(Ph.D. Lee, sung won)of Nongam Lee, Hyeon Bo and local site survey and original landscape was reproduced by making its result as a drawing and preparing an estimated map around this area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.77-84
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• 2018

As the application of BIM (Building Information Modeling) to the civil sector has become practical, and mandatory for road projects, the standardization, development of systems, etc. for the application and operation of BIM are required. In particular, it is important to develop BIM data standards for producing, sharing and managing the lifecycle data of civil facilities because they are commonly national public facilities. The BIM data standards have been developed by utilizing or extending IFC (Industry Foundation Classes), which is an international standard, but schema extensions of river facilities has not been developed thus far. This study proposes an approach to an IFC extension for river facilities using the WBS (Work Breakdown Structure) as a fundamental study for IFC-based schema extension in the river field. For this purpose, the research was carried out as follows. First, the IFC extension development method was selected to represent the river facilities by analyzing the existing IFC structure and previous research cases for the IFC extension. Second, extended elements of the river facilities were identified through an analysis of the WBS and classified according to the high-level structure of the IFC schema. Third, the classified elements were arranged based on the IFC hierarchy and the IFC schema extension for river facilities was established. Based on the suggested extension method of IFC schema, this study developed the schema by defining the element components and parts of river facilities, such as distribution flow elements and deriving their detailed types and properties.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.43-48
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• 2007

본 연구는 벼 군락의 분광반사율 지표를 측정할 수 있는 인공광원을 사용하는 능동형 광학 센서인 GNDVI 를 활용하여 생육시기별 식생지수와 엽 질소함량과의 관계를 구명하여 벼 군락의 엽 질소함량을 추정하고자 하였다. 농업과학기술원 답작 포장에서 공시품 종인 추청벼를 이용하여 난괴법 3반복으로 시험구 배치를 하고 질소 4수준 3반복으로 실험을 수행하였다. 벼 생육시기별 GNDVI 와 엽 질소함량과의 관계를 2년 간 (2005, 2006)의 자료를 통하여 분석해 보았다. 2005년의 경우 벼 생육시기동안 9시기의 GNDVI값과 그 당시 시료를 샘플링하여 분석한 엽 질소함량과의 관계를 벼 출수전과 출수후로 구분하여 분석해 본 결과 GNDVI 값은 출수전 ($r=0.78^{***}$ n=60) 보다 출수후 ($r=0.89^{***}$, n=59) 가 엽 질소함량과의 상관계수가 높았다. 2006년은 20시기동 안 생육시기별 식생지수와 엽 질소함량과의 상관 분석한 결과 착근기 (6월 5일) $r=0.84^{***}$, 유수분화기 (7월 11일) $r=0.95^{***}$, 출수기 (8 월 16일) $r=0.87^{***}$, 수확기 (10월 13일) $r=0.90^{***}$ 으로 출수전의 경우 7월 11일이 상관계수가 가장 높았고， 이 결과는 2005년 동일시기 (7월 11일) 식생지수와 벼 엽 질소함량과의 상관계수가 가장 높았던 ($r=0.91^{***}$) 것과 일치하였다. 벼 생육시기 변화에 따른 식생지수와 엽 질소 흡수량과의 관계를 살펴보았는데 벼 출수전의 경우 GNDVI는 7월 11일 에 엽 질소 흡수량과의 상관계수 ($r=93^{***}$)가 가장 높은 결과를 보였고 출수후의 경우에는 시기에 따라 상관계수가 고르게 높게 나타났다. 엽 질소함량과의 상관관계가 높았던 2005년，2006년 7월 11일 식생지수 데이터를 함께 이용하여 엽 질소함량과의 관계를 추정식으로 작성하였다. GNDVI를 이용하여 2005년과 2006년 실측한 엽 질소함량 값과 추정 값을 비교해 본 결과 2005년과 2006년의 결정계수가 각각 0.88, 0.94로 2006년이 더 예측률이 높게 나타났다. GNDVI 값을 이용하여 엽 질소함량 추정값과 실측값을 비교해 본 결과 결정계수가 0.86으로 추정값과 실측값이 근접하게 분포하였다.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.25-36
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• 2017

In the 1994 Northridge earthquake, connection damage initiated from the beam bottom flange was prevalent. The presence of a concrete slab and resulting composite action was speculated as one of the critical causes of the prevalent bottom flange fracture. In this study, four seismic retrofit schemes are proposed in order to salvage welded steel moment connections with composite floor slabs in existing steel moment frames. Because top flange modification of existing beams is not feasible due to the presence of a concrete floor slab, three schemes of bottom flange modification by using welded triangular or straight haunches or RBS(reduced beam section), and beam web strengthening by attaching heavy shear tab were cyclically tested and analyzed. Test results of this study show that haunch and web-strengthened specimens can eliminate the detrimental effect caused by composite action and ensure excellent connection plastic rotation exceeding 5% rad. Design recommendations for each retrofit scheme together with supplemental numerical studies are also presented.