• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.109-110
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• 2009

"드럼 코아시편 채취장치" 는 침출/내수성 시험, 압축강도 측정시험, 열 순환 시험등 의 파괴적 물성시험을 수행하기 위해서 경질(시멘트 고화체) 및 연질(파라핀왁스) 등의 방사성폐기물드럼으로부터 코아 시료를 채취하는 장비이다, 시편채취의 최대길이는 860 mm 이며 코아 시편의 직경은 50~200 mm 이며 일반적으로 "방사성폐기물 고화체의 물성시험"에 사용되는 시편은 실험실적으로 제조한 소규모 모의 고화체 시편과 고화공정에서 직접 채취한 소규모 시편, 200L 드럼으로부터 코아시편을 채취 가공하여 만든 시편과 같이 3종류가 있다. 고화공정에서 발생되는 고화체는 일반적으로 200 L 드럼에 주입되며, 고화체의 균일성 정도는 고화공정의 특성, 폐기물/고화매질 혼합비, 200 L 고화체 드럼의 냉각방식에 따라 다르다. 따라서, 실험실에서 제조한 시편과 공정에서 채취한 소규모시편은 실제 고화공정을 대표할 없으며 또한 실제 발생된 고화체의 조성과도 동일하다고 볼 수 없다. 따라서 200 L 드럼으로부터 코아시편을 채취하여 만든 시편이 고화공정과 고화체를 대표할 수 있는 시편으로 볼 수 있다 그러므로 고화체 및 고화공정을 대표할 수 있는 코아시편을 채취할 수 있는 장치를 제작하여 다양한 코아시편을 200 L 고화체 드럼으로부터 수직 코아시편을 채취할 필요가 있으며 실험에서 코아시편 채취속도와 연관된 Z-AXIS 의 Rpm은 운전범위는 0-2000 Rpm 이나 이때 너무 빠른 속도는 기계에 치명적인 손상을 초래 할 수 있으므로 위험한 것으로 나타났으며 500-1000 Rpm 의 속도가 적합한 것으로 시험되었으며 시편을 절삭하는 Spindle의 Rpm은 운전범위는 0-1500Rpm 이나 무리한 운전을 피해 가장 적절한 Speed로 운전해야하며 시험결과 500-800Rpm 이 최적운전범위로 나타났다 또한 시멘트고화체에서의 코아 채취시험에서는 Spindle의 속도는 500 Rpm, Z -AXIS 의 Rpm은 900 Rpm이 가장 적합한 것으로 나타났으며 성능평가시험을 통하여 비트부의 절삭속도와 Z축의 이동속도에 관한 그라프를 획득하였으며 시편의 크기에 따라서 Spindle의 속도를 증감하여야함을 확인할 수 있었다.

• Journal of the Korean Geophysical Society
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• v.2 no.4
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• pp.269-276
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• 1999

As a part of trying to get the resistivity values correctly from laboratory core resistivity measurement, the effect of sample holders in resistivity measurement was analyzed and a better way to determine the representative resistivity value from the time series resistivity data was searched. Modified GS type and modified two-electrode type sample holders were devised and their effects have been compared with those of GS and two-electrode type sample holders. The modified two-electrode type sample holder has benefits both in repetition and simplicity in data acquisition. The analysis of distribution trend of the time series resistivity data obtained with different kind of sample holders and source frequencies shows that the maximum curvature point method gives the best result in determining representative resistivity value.

• Journal of KIISE
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• v.43 no.1
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• pp.40-46
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• 2016

Digital road map generation is primarily based on artificial satellite photographing or in-site manual survey work. Therefore, these map generation procedures require a lot of time and a large budget to create and update road maps. Consequently, people have tried to develop automated map generation systems using GPS trajectory data sets obtained by public vehicles. A fundamental problem in this road generation procedure involves the extraction of representative trajectory such as main roads. Extracting a representative trajectory requires the base data set of piecewise line segments(GPS-trajectories), which have close starting and ending points. So, geometrically similar trajectories are selected for clustering before extracting one representative trajectory from among them. This paper proposes a new divide- and-conquer approach by partitioning the whole map region into regular grid sub-spaces. We then try to find similar trajectories by sweeping. Also, we applied the $Fr{\acute{e}}chet$ distance measure to compute the similarity between a pair of trajectories. We conducted experiments using a set of real GPS data with more than 500 vehicle trajectories obtained from Gangnam-gu, Seoul. The experiment shows that our grid partitioning approach is fast and stable and can be used in real applications for vehicle trajectory clustering.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.631-638
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• 2023

This paper is to introduce methodologies of travel time reliability evaluation using daily traffic volumes. The methodologies include desirable speed concept, the relation between averaged daily speeds and daily traffic volumes, the standardized way in integration of travel time deviations obtained from continuous highway sections. The study began with traffic data collection from a freeway line with long lasting congestion. And then, provided establishment of the relation between averaged daily speeds and daily traffic volumes, and usability of Point estimate method (PEM) to integrate travel time deviations of sections. Based on the relation between averaged daily speeds and daily traffic volumes, it is identified that travel time reliability begins to decrease around LOS (Level of Service) C even before LOS D or F. It may be concluded that travel time reliability could be evaluated based on daily traffic volumes in highway sections using standardized PEM. The methodologies introduced in the paper, could be useful in practicing evaluation of travel time reliability during the works of highway operation or highway planning.

• Journal of Navigation and Port Research
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• v.35 no.1
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• pp.57-62
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• 2011

On the view point of renewable energies as energy sources of district heating and cooling plant, the purpose of this study is to develop, classify and map the 500m${\times}$500m mesh, of which is treated as normal size in DHC regulations for evaluation process. Followings are the results. Various building and geographical informations including 13 districts and 108 counties are re-defined to create 500m${\times}$500m meshes, and it is find out that 3,289 meshes among 8,463 meshes have meaningful floor areas. Only 59 meshes(1.8%) are evaluated as mesh which has more than 50% of building volume ratio per mesh. 5 clusters classified by principal analysis and cluster analysis with building needs' characteristics are defined. Gwang-an Dong is representative of cluster 1 characterized as commercial area, and the cluster 4, 5 which has mainly residential needs are distributed in Yong-ho dong. Because there are a lot of cluster 3 meshes, which has complex needs area based on residential, cluster 3 could be defined as representative of Busan metropolitan city.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.9-18
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• 2020

The purpose of this study is to suggest a method of predicting seismic vulnerability and safety conditions of each building in a targeted area. The scope of this study includes 'developing a simulation model for precaution activities,' 'testing the validity of the developed model', From the facility point of view, target of this study is a local building system. According to the literature review, the number of earthquake prediction modeling and cases with GIS applied is extremely few and the results are not proficient. This study is conducted as a way to improve the previous researches. Statistic analyses are conducted using 348 domestic and international data. Finally, as a result of the series of statistical analyses, an adequate model is developed using optimization scale method. The ratio of correct expectation is estimated as 87%. In order to apply the developed model to predict the vulnerability of the several chosen local building systems, spatial analysis technique is applied. Gangnam-gu and Jongro-gu are selected as the target areas to represent the characteristics of the old and the new downtown in Seoul. As a result of the analysis, it is discovered that buildings in Gangnam-gu are relatively more dangerous comparing to those of Jongro-gu and Eunpyeong-gu.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.132-132
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• 2003

포도 중 캠벨얼리 품종은 색이 검붉고 당도가 높아 우리나라 대표적인 품종 중에 하나로 알려져있다. 그러나 수확 후 저장 유통 중 품질이 저하되기 쉽다. 따라서 예냉 조건 및 수송, 저장, 유통조건에 따른 품질조사를 비교실험하여 가장 안전한 저장 유통 방법을 개발하고자 하였다. 실험재료는 2003년 8월20일경에 포도 주산지인 영천 농가에서 수화 한 후 바로 예냉처리를 하였다. 이때 사용한 예냉기는 원예연구소에서 개발한 시제작품을 사용하였다. 대조구로 무예냉을 두었으며 예냉 후 수송온도도 관행적인 상온과 저온(2$^{\circ}C$)로 구분 처리하였으며 저온온도별로도 함께 실험하였다. 포장단위도 2kg 와 5kg로 각각 처리하여 수행하였다. 예냉이 품질에 미치는 영향을 조사하기 위하여 예냉처리에 따른 호흡패턴 변화와 이화학적 특성변화를 조사하였다. 또한 저장 중 중량감소율, 부패율 및 탈립율을 조사하였다. 포도 ‘켐벨얼리’의 수확 시 품온 29.5$^{\circ}C$를 적정 저장 온도인 2$^{\circ}C$로 저하시키는데 일반 저온 저장고에서 10시간 정도 걸리는 데 반하여 차압예냉기 이용시 3시간으로 단축시킬 수 있었으며 예냉 포도의 처리구별 호흡량은 초기 6.65$m\ell$/kg/hr 였으나 상온무예냉 및 예냉 처리구의 경우에는 저장해가면서 급격히 증가되었고 저온에서는 무예냉의 경우에는 계속 증가되는 반면 예냉 처리구의 경우에는 포장 규격과는 상관없이 다른 처리구 보다 호흡억제 효과가 있었다. Ethylene 발생량 역시 호흡과 비슷한 경향을 보여 주어 예냉 시 과실의 품질 저하 요인 발생량을 억제시킬 수 있었다. 경도는 저장 기간이 경과됨에 감소되나 저온 예냉 처리구의 경우가 초기 1.26N을 높게 유지하였고 자연중량 감모율은 상온저장 2주째 무예냉처리구 8.40%로 감소된데 비하여 예냉 저온 수송 구의 경우에는 0.25%로 매우 낮았다. 포도 ‘켐벨얼리’의 저온 저장중 부패율은 저장 2주째 상온 무예냉 처리구의 경우 19.8%이었으나 저온 예냉 처리구의 경우는 부패과가 발생하지 않았고 탈립율 역시 상온무예냉처리구의 경우 53.5%인데 반하여 저온 예냉 처리구는 저장 4주경과 시까지 탈림과가 없었다. 당도 및 pH변화 역시 차압 예냉 후 저온 수송 처리구가 초기당도(12.0Bx)$^{\circ}$값과 초기 pH(3.8)를 저장 25일 경과시까지 유지하였다. 수확 시 높은 품온을 갖고 있는 과일을 산지에서 예냉 처리를 한 후 저온 냉장차를 이용하여 유통한다면 관행 유통 구조보다 고품질의 포도를 유통시킬 수 있는 것으로 사료되며 앞으로는 완숙된 고 당도(12.0~15.0Bx)$^{\circ}$ 포도를 수확 한 즉시 예냉 처리하고 저온 유통한다면 보다 신선한 과일을 소비자에게 전달 할 수 있을 것이다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.110-118
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• 2018

Due to recent earthquakes, there is a growing awareness that Korea is not a safe zone for earthquakes any more. Therefore, the review of various aspects of the seismic safety of the infrastructures are being carried out. Because of the characteristics of the underground structure buried in the ground, the electric power utility tunnels must be considered not only for the inertia and load capacity of the structure itself but also the characteristics of the surrounding soils. An extensive and accurate numerical analysis is inevitably required in order to consider the interaction with the ground, but it is difficult to apply the soil-structure interaction analyses, which generally requires high cost and extensive time, to all electric power utility tunnel structures. In this study, the major design variables including soil characteristics are considered as independent variables, and the seismic safety factor, which is the result of the numerical analysis, is considered as a dependent variable. Thus, a method is proposed to select vulnerable electric power utility tunnels with low seismic safety factor while excluding costly and time-consuming numerical analyses through the direct correlation analysis between independent and dependent variables. Equations of boundary limits were derived based on the distribution of the seismic safety factor and the cover depth and rebar amounts with high correlation relationship. Consequently, a very efficient and simple approach is proposed to select vulnerable electric power utility tunnels without intensive numerical analyses. Among the 108 electric power utility tunnels that were investigated in this paper, 30% were screened as fragile structures, and it is confirmed that the screening method is valid by checking the safety factors of the fragile structure. The approach is relatively very simple to use and easy to expand, and can be conveniently applied to additional data to be obtained in the future.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.47-57
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• 2012

We have measured soil enzyme activities, which represent the rates of organic matter decomposition, in four riparian ecosystems in Korea. ${\beta}$-glucosidase, N-acetylglucosaminidase, phosphatase and arylsulfatase activities were determined in five occasions over a year period in soils of control plots and plots with invasive plants, namely Sicyos angulatus and Humulus japonicus. Significantly higher enzyme activities were found in soils with invasive plant in barren land, but the difference was season and enzyme-specific. Although it was not universal changes, the invasive plants appeared to accelerate organic matter decomposition in some disturbed riparian ecosystems.

• Journal of Korean Society of Transportation
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• v.28 no.6
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• pp.159-166
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• 2010

Trip distribution is to connect travel demand for each OD pair based on travel cost, trip production and attraction derived from trip generation step. In real world the travel cost is a function of travel demand, but existing models could not fully consider such functional relation between travel cost and demand, which leads to an equilibrium in trip distribution model. This paper proves the equilibrium trip distribution by using gravity model. In order to obtain such equilibrium this paper also presents a solution algorithm based on fixed point theorem. The algorithm will be tested with an example and confirmed the equilibrium solution of trip distribution.