• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.5
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• pp.413-420
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• 2012

In this study, the Kernel integration scheme for 2D linear elastic direct boundary element method has been discussed on the basis of subparametric element. Usually, the isoparametric based boundary element uses same polynomial order in the both basis function and mapping function. On the other hand, the order of mapping function is lower than the order of basis function to define displacement field when the subparametric concept is used. While the logarithmic numerical integration is generally used to calculate Kernel integration as well as Cauchy principal value approach, new formulation has been derived to improve the accuracy of numerical solution by algebraic modification. The subparametric based direct boundary element has been applied to 2D elliptical partial differential equation, especially for plane stress/strain problems, to demonstrate whether the proposed algebraic expression for integration of singular Kernel function is robust and accurate. The problems including cantilever beam and square plate with a cutout have been tested since those are typical examples of simple connected and multi connected region cases. It is noted that the number of DOFs has been drastically reduced to keep same degree of accuracy in comparison with the conventional isoparametric based BEM. It is expected that the subparametric based BEM associated with singular Kernel function integration scheme may be extended to not only subparametric high order boundary element but also subparametric high order dual boundary element.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.891-897
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• 2004

This paper provided a simulation model for transport vehicles that carry container from the ship to yard block and vice versa at automated container terminal with a perpendicular yard layout. Usually, the efficiency of container terminal is evaluated by the productivity of container cranes at apron, and the stevedoring system for transport vehicles and yard cranes should be supported enough to improve productivity of container cranes. Especially, transport vehicle is very important factor in the productivity of container cranes and the performance of transport vehicles are changed according to the number and traveling type of vehicles. For these reason, a method that can estimate productivity of transport vehicle is required Finally, we developed the simulation model to analyze the productivity of transport vehicle and presented the productivity of container cranes for a varying operation of transport vehicles.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.443-449
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• 2004

In this paper, we established a simulation model for transport vehicle that carries the container transportation between apron and yard block on automated container terminal with a perpendicular yard layout. Usually, the efficiency of container terminal is evaluated by productivity of container cranes at apron, and though there are enough support of transport vehicles and yard cranes, can improve the productivity of container cranes. Especially, transport vehicle is very important factor in productivity of container cranes and has variable work productivity according to loading and unloading situation of container cranes. Therefore, a method that can estimate work productivity of transport vehicle efficiently is required. We analyzed work productivity of transport vehicle using simulation model that has state transition of transport vehicle. We performed various simulation experiment and analyzed work productivity of transport vehicle and calculated the required number of transport vehicle by container crane additionally.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.236-236
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• 2011

진천지역의 지하수 유동체계를 분석하기 위해 진천지역 내 530개 공의 지하수위를 1년간 관측하였다. 이중 360개 공에서는 분기별로 한번씩 총 4회, 130개 공에서는 월1회씩 총 12회 지하수위를 관측하였으며, 40개 공에 대해서는 1시간 간격으로 자동관측을 실시하였다. 관측결과를 수집하여 지하수위의 변동특성, 지하수위 분포, 지하수 심도분포 등을 실시하였으며, 이와 같은 지하수위 분석 결과를 바탕으로 지하수 유동체계를 분석하였다. 조사지역의 평수기 지하수위 분포에 대해 수리학적인 접근법(hydraulic approach) 및 동수역학적 접근법(hydrodynamic approach)에 근거하여 수리수두(hydraulic head) 및 전수두(total head)를 분석하여 2차원 및 3차원 수리경사도를 작성하였다. 이러한 지하수위 분포에 따른 분석 성과와 지형 및 수문지질을 고려하여 함양 및 배출지역을 분류하였으며, 이와 함께 기분석된 지하수위 등고선에 따른 유선망도를 작성하였다. 지하수는 지하수위의 표고 및 압력에 따른 위치 에너지 차에 의하여 대수층 매질을 통하여 유동하며 수두가 높은 곳에서 낮은 곳으로 일정한 수리경사를 갖고 지하수 등수위선에 연직 방향으로 형성된 유선을 따라 이동한다. 따라서 지하수의 유동방향은 지하수 수리경사 분석이 이루어진 8개 방향의 지하수위 경사 중 최대경사를 갖는 방향으로 지하수 유동이 발생하므로, 이를 지하수위 유동방향으로 결정하였다. 이와 같이 분류된 지하수 함양 중간 및 배출 지역과 지하수의 함양과 배출의 양적인 측면에 서 유동체계의 규모를 고려하여 조사 지역을 8단계로 구분하였다. 또한 조사지역의 지하수 유동체계를 종합적으로 규명하기 위하여 기 분석한 조사지역의 지하수위 등고선, 지하수위 등심도선, 지하수 수리경사, 지하수 유동방향 및 지하수 함양-배출체계와 지형기복, 그리고 주요 하천 등의 제반 요소를 중첩 분석하여 종합적으로 규명하고, 그 결과를 지하수 유동체계도로 작성하였다. 지하수 유동체계 분석결과는 수문지질 평가와 오염취약성 평가 및 지하수 관리 방안 수립에 활용될 수 있을 것으로 기대된다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.266-269
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• 2006

지하수, 해수 혹은 지표수의 희토류원소의 분포도에 있어서 Eu과 Ce은 산화수의 변화에 따라 다른 희토류원소로터 벗어나게 되고, 이로이해 Eu과 Ce의 이상이 발생된다. 지표수와 지하수의 연계성을 밝혀내기 위해 희토류원소를 이용하여 전주-완주지역에서의 지표수와 지하수시료를 2002년부터 2004년까지 6차례에 걸쳐 채취하였다. 이중 2003년 8월까지의 시료는 2개기관에서 각각 희토류원소 함량을 측정하였다. 또한 대수층 구성암석과의 상관성을 밝혀내기 위해 동일한 지역에서 코어시료를 채취하였다. PAAS(Post Archean Australian Shale)로 규격화한 희토류 원소분포도에 의하면, 갈수기인 2002년 4월과 2003년 11월의 지표수와 지하수는 대체적으로 중희토류가 부화되었고, 아울러 강한 Eu의 정(+)의 이상과 Ce의 부(-)의 이상을 보여주었다. 그러나 갈수기가 끝난 2003년 6월과 장마가 끝난 직후인 2003년 8월의 시료에서는 대부분의 지표수와 지하수 시료가 Eu의 강한 부(-)의 이상을 보여주었다. 그리고 일부 시료에서는 Ce의 부(-)의 이상도 관찰되었다. 이와 같은 Ce과 Eu의 변화는 산화-환원작용의 영향을 받은 산화수(즉 Ce3+와 Ce4+, Eu2+와 Eu3+)의 변화에 의한 것으로 해석할 수가 있다. 뿐만 아니라, 본 연구결과에 의하면, 전주-완주 지역에서의 지표수와 지하수는 매우 밀접한 연관성을 갖고 있으며, 그 순환속도 또한 비교적 빠른 편으로 나타났다. 그리고 본 연구결과, 희토류원소는 지표수와 지하수의 연계성을 밝혀내는 데 있으며 매우 유용한 지시자임을 확인하였다.

• The Journal of Engineering Geology
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• v.9 no.3
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• pp.227-241
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• 1999

Groundwater flow in a fractured rock mass is related to the geometric characteristics of the fracture system. The objective of this study aims to analyze the probabilistic density function of fracture properties md their relations to the hydraulic conductivity in volcanic rocks of the northern Yosu area. Fracture characteristics were investigated by core logging and acoustic televiewer logging in four boreholes and the hydraulic conductivity was obtained from the constant pressure injection and fall-off tests. The 303 fractures were grouped into three sets by their orientation and three fracture types by the degree of opening in aperture. As a result of the study, the hydraulic conductivity in the test section intersected by open and semi-open fractures, conductive fractures, and set 1 fractures was very high, while closed fractures did rarely affect the hydraulic conductivity. It was recognized that the hydraulic conductivity in a fractured rock mass was preferentially affected by the aperture size of conductive fractures and fracture intersection frequency and size, secondly.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.1
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• pp.11-18
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• 2003

As the Internet moves to mobile environment, one of the most serious problems for the security is to required a new security Protocol with safety and efficiency. To solve the problem. we Propose a new Protocol that reduces the communication franc and solves the problem associated with the private security keys supplied by the trusted third party. The protocol is a non-Interactive oblivious transfer protocol, based on the EIGamal public-key algorithm. Due to its Non-Interactive oblivious transfer protocol, it can effectively reduce communication traffic in server-client environment. And it is also possible to increase the efficiency of protocol through the mechanism that authentication probability becomes lower utilizing a challenge selection bit. The protocol complexity becomes higher because it utilizes double exponentiation. This means that the protocol is difficult rather than the existing discrete logarithm or factorization in prime factors. Therefore this can raise the stability of protocol.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.177-185
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• 2005

Data from 122 pumping tests were obtained from 100 boreholes in granites, volcanic rocks, metamorphic rocks, and Cretaceous and Tertiary sedimentary rocks, and then were analyzed using AQTESOLV. Results from 86 of the 122 tests ($71\%$) have an analytical solution corresponding to Theis (1935), Cooper-Jacob (1946), Papadopulos-Cooper (1967), Hantush (1962), Moench (1985), or Hantush-Jacob (1955), whereas the remaining 36 results ($29.5\%$) do not correspond to any of the analytical methods. Of the 86 results, only 17 match the Theis and Cooper-Jacob methods, indicating that the basic methods fer pumping test analysis are useful far only $14\%$ of the total data. This suggests that analytical solutions derived using leaky boundary conditions are appropriate for the analysis of pumping test data in fractured aquifers in this study. Furthermore, the results show the importance of carefully selecting an appropriate model for the analysis of pumping test data. Results from the 122 pumping tests were also analyzed using the GRF model. Using the Barker method, the results show that 77 of the 122 tests ($63\%$) have dimensions ranging between 1.1-2.9. Of these 77 solutions, ($39(44.2{\%})$) have a fractional dimension of 1.1-1.9, ($26(6.5{\%})$) show 2-dimensional radial flow also applicable to the Theis method, and ($38(49.3{\%})$) have dimensions of 2.1-2.9. The results show that groundwater flows according to a fractional flow dimension in fractured aquifers.

• Korean Journal of Food Science and Technology
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• v.13 no.1
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• pp.43-52
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• 1981

A series of thermal destruction studies of the most heat resistant yeast strain No. 15 among 61 isolates were conducted in order to establish the optimum pasteurization condition of peach solid pack. The results obtained are summarized as follows: 1. A survival curve of the selected yeast strain No. 15 at $58^{\circ}C$ consisted of heat labile and heat stable fraction, showing broken curve. 2. The actively growing cell showed less recovery rate than 10 day rested cell after agitation-growing for 90 hr. For heating menstrua, peptone solution gave higher recovery rate than peach juice. For recovery medium, YM agar gave higher recovery rate than peach juice agar. The selected yeast was more resistant to heat at pH 4.0 than at pH 3.5 in both heating menstrua and recovery medium. 3. Z value of TDT curve of the selected yeast (heating : at pH 3.5 in peach juice. recovery: at pH 3.5 in peach juice agar) was $4.8^{\circ}C$. 4. The selected yeast No. 15 was identified as Torulopsis candida. 5. In the inoculated pack test of 4 oz can, it was concluded that the optimum P.U. 70/5 was 168 (center temp; $78.5^{\circ}C$, initial temp; $18^{\circ}C$, processing time; 18 min, initial yeast count; $1.0{\times}10^7$ per can).

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.504-515
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• 2012

Groundwater is widely used as drinking water supplies around the world. However, microbial contamination of groundwater is a serious environmental problem that degrades drinking water quality and poses a great threat to human health. Among the pathogenic microorganisms such as viruses, bacteria, and protozoa, viruses are not readily removed during transport through soils, having high mobility in groundwater environment due to their smaller size compared to bacteria and protozoa. Studies regarding the fate and transport of viruses in soils and aquifers are necessary to determine the vulnerability of groundwater to microbial contamination and to secure safe drinking water sources. Also, these studies provide important information to establish the regulations and policies related to public health. This review paper presented the field and laboratory studies conducted for the fate and transport of viruses in subsurface environments. Also, the paper provided the factors affecting the fate and transport of viruses, the characteristics of bacteriophages used for virus studies, and virus transport model/colloid filtration theory. Based on this review work, future researches should be performed actively to set up the viral protection zone for the protection of groundwater from viral contamination sources. Especially, the researches should be focused on the development of mathematical models to calculate the setback distance and travel time for the viral protection zone along with the accumulation of information related to the model parameters.