• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2005년도 2005 Annual Meeting & International Symposium
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• pp.54-62
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• 2005

While genomics (the set of experimental and computational tools that allows the blueprints of life to be read) opens the doors to a more rational approach to the design and use of living cells to bring about desirable chemical transformations, genomics is, by itself, insufficient. We need tools that allow us to relate genomic and molecular information to cellular physiology and then to the response of a population of cells. We propose the development of hybrid computer cellular models. In such models genomics and chemical detail for a cellular subsystem (e.g. pathogenesis) is embedded in a coarse-grain cell model. Such a construct allows the quantitative and explicit linkage of genomic detail to cell physiology to the extracellular environment. To illustrate the principles involved we are constructing a model for a minimal cell. A minimal cell is a bacterial cell with the fewest number of genes necessary to sustain life as a free living microbe.

• 대한기계학회논문집
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• 제8권3호
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• pp.224-231
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• 1984

본 연구에서는 이상과 같은 점을 고려하고, 인장시험을 통해 최대용접강도를 나타내는 최적용접조건을 구한 다음, 최적조건하에서 박강판을 1점 점용접한 재료의 너깃주위에 관찰되는 파괴거동을 광탄성 응력분포거동과 관련시켜 고찰하였다.

• 한국IT서비스학회지
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• 제10권3호
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• pp.113-126
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• 2011

The smelting and the continuous casting of steel are important processes that determine the quality of steel products. Especially most of quality defects occur during solidification of the steel continuous casting process. Although quality control techniques such as six sigma, SQC, and TQM can be applied to the continuous casting process for improving quality of steel products, these techniques don't provide real-time analysis to identify the causes of defect occurrence. To solve problems, we have developed a detection model using decision tree which identified abnormal transactions to have a coarse grain structure. And we have compared the proposed model with models using neural network and logistic regression. Experiments on steel data showed that the performance of the proposed model was higher than those of neural network model and logistic regression model. Thus, we expect that the suggested model will be helpful to control the quality of steel products in real-time in the continuous casting process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.971-989
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• 2015

With the development of cloud computing, more and more Web services are deployed on geo-distributed datacenters and are offered to cloud users all over the world. Through service composition technologies, these independent fine-grain services can be integrated to value-added coarse-grain services. During the composition, a number of Web services may provide the same function but differ in performance. In addition, the distribution of cloud datacenters presents a geographically dispersive manner, which elevates the impact of the network on the QoS of composite services. So it is important to select an optimal composition path in terms of QoS when many functionally equivalent services are available. To achieve this objective, we first present a graph model that takes both QoS of Web services and QoS of network into consideration. Then, a novel approach aiming at selecting the optimal composition path that fulfills the user's end-to-end QoS requirements is provided. We evaluate our approach through simulation and compare our method with existing solutions. Results show that our approach significantly outperforms existing solutions in terms of optimality and scalability.

• 한국철도학회논문집
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• 제17권1호
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• pp.43-51
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• 2014

철도에서 토공구조물은 입경이 큰 조립지반재료를 주요한 재료로 사용하고 있다. 그러나 이들 재료에 대한 미소변형 거동을 평가할 수 있는 동적물성 산정에 대한 연구는 대형시험장비의 부족으로 거의 이루어지지 않고 있다. 이에 본 연구에서는 국내 철도설계기준에 제시되어 있는 입도분포, 단위중량 등의 기본 조건에 맞는 강화노반(보조도상, 입도조정층), 접속부 자갈재료, 상부노반재료에 대해 대형반복삼축압축시험을 수행하여 저변형률 수준에 따른 정규화전단탄성계수와 감쇠비곡선을 제안하고, 각 재료별로 수식 모델과 계수를 제시하였다.

• 산업기술연구
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• 제22권A호
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• pp.153-159
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• 2002

This paper is an experimental work of estimating friction angle of very coarse grained soil such as rubble mound by performing laboratory experiments. Two crushed rocks of rubble mound were used for tests. Triaxial compression tests with drained conditions were performed to measure friction angles of soils prepared by mixing the crushed soil having an identical coefficient of uniformity with different maximum grain size distribution. Centrifuge model experiments with those soils were also performed to measure angle of repose and to estimate friction angle of soil from measuring the slope of slip line in the active stress state. Model tests were carried out by changing the G-levels of 1G and 50G. From triaxial compression tests, the measured value of friction angle of soil is in the range of $41{\sim}57^{\circ}$. The measured value of repose angle is in the range of $32{\sim}35^{\circ}$. The values of friction angle are found not so sensitive to the maximum grain size of soil as long as the coefficient of uniformity is identical. Estimated value of friction angle from measuring the slope of slip line in the active stress state is in the range of $30{\sim}46^{\circ}$. Thus, the estimated angle of friction are found to be greater in the order of the measured angle of repose, the estimated value from the slope of active state, and triaxial compression test results. On the other hand, the measured values of friction angle from triaxial tests were compared with empirical equations, based on the relation between friction angle and void ratio. Equations proposed by Helenelund(l966) and Hansen(1967) found to be relatively reliable to estimate friction angles of soil.

• 대한임베디드공학회논문지
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• 제4권1호
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• pp.35-41
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• 2009

The H.264/SVC enables network-adaptive video transmission to smart device which uses wireless network. But, quality scalability of H.264/SVC does not consider personal subjective image quality. In addition, its network efficiency also does not optimized because it uses MGS(Medium Grained Scalability) and CGS(Coarse Grained Scalability). Thus, this paper proposed a new scalable ROI algorithm for not only subjective image quality improvement but also network adaptation. To experiment our proposed a scheme, we added designed algorithm to JSVM(Joint Scalable Video Model) open source video codec of H.264/SVC. Experiment was performed according to the pre-defined scenario for simulating various network conditions. Finally, experimental result showed our proposed scalable ROI scheme. It is better than traditional non-selective scheme in subjective video quality.

• 한국재료학회지
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• 제11권4호
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• pp.266-271
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• 2001

Al-Cu-Mn 주조합금의 응력부식균열 저항성에 미치는 Cd첨가의 영향을 C-ring test와 전기전도도 시험을 통하여 조사하였다. Cd첨가량이 증가함에 따라 전기전도도가 증가하였고 SCC 저항성도 증가하였다. SCC 시험결과 균열이 입계를 따라 전파되는 입계파괴가 일어났으며, 파면은 취성파괴양상을 나타내었고, 입계를 따라 조대 석출물과 무석출대가 나타난 것으로 보아서 이 합금의 SCC 기구는 anodic dissolution model이라고 판단된다. Cd을 첨가하지 않은 경우 최대경도값은 127Hv였으나, Cd을 첨가한 경우 최대경도값은 138∼146Hv로 증가하였다.

• 한국해양학회지:바다
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• 제3권2호
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• pp.59-70
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• 1998

가로림만 조간대 표층퇴적물의 입도조직변수(평균입도, 분급도 및 왜도)를 기초로 '이차원 퇴적물 이동벡터모델'을 이용하여 퇴적물의 이동방향을 추정하였고 이에 따른 퇴적물의 이동현상을 해석하였다. 채취된 퇴적물은 각 정점마다 전체와 조립질(< 4.5 ${\phi}$)로 구분하여 각각의 퇴적물이동방향(15 경우)을 구하였고, 이 방향과 지형, 층면형태(bedform)의 정밀측정, 그리고 여러 번의 현장관찰을 기초로 결정된 퇴적물의 실제이동방향과 비교하였다. 퇴적물의 실제이동방향과 가장 일치하는 이동벡터는 조립질 퇴적물에서 퇴적물 이동방향으로 퇴적물이 세립해지고, 분급이 좋아지며 왜도가 감소하는 경우와 퇴적물이 조립해지고, 분급이 좋아지며 왜도가 증가하는 경우를 조합한 M 경우이다. 이는 조립질 퇴적물이 연구지역의 퇴적물이동에 주요 구성성분이며, 세립질(> 4.5 ${\phi}$)을 포함하는 전체 퇴적물보다 퇴적기작이 더 단순하므로 '퇴적물이동벡터모델'과 잘 부합하는 것으로 보인다. 또한 전체 퇴적물과 조립질 퇴적물 모두 퇴적물의 이동방향으로 분급도가 좋아지는 경향이 뚜렷한데, 이는 퇴적기작의 복잡성과 관계없이 연속적인 수리에너지는 퇴적물의 분급을 더 좋게 한다는 것을 증명한다. 또한 이 연구결과를 통하여 사주조간대의 조립질퇴적물의 이동은 남북방향으로 놓여 있는 만 입구 동주수로를 통하여 저조선에서 상부조간대로 이동하면서 퇴적되었고, 일부는 동주수로를 지나 남수로로 공급되어 반시계방향으로 돌며 북쪽지역으로 이동 퇴적되었음이 밝혀졌다. 조립질 퇴적물은 사주에 퇴적되지만, 일부는 북수로를 따라 썰물때 다시 만밖으로 나가는 것으로 퇴적물이동벡터모델이나 퇴적물 실제이동방향의 관찰 모두에서 증명되었다. 따라서 북수로 및 북동쪽 뻘질모래지역은 만 밖에서 운반된 부유퇴적물과 조립퇴적물이 동시에 퇴적되는 지역이며, 지역적으로 조립질과 세립질의 분리퇴적현상이 때때로 관찰되기도 하는 수리역학적 퇴적물 혼합지역이다. 사주의 육지이동과 북수로 발달현상은 조립퇴적물이 만 밖이나 만 입구 등 근원지(장안퇴를 포함한 사퇴)로부터 더 많이 유입되었거나 혹은 상대적 해수면의 상승의 결과로 보인다.

• Geomechanics and Engineering
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• 제17권5호
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• pp.485-496
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• 2019

Sealing of leakage in waterfront or water-retaining structures is one of the major issues in geotechnical engineering practices. With demands for biological methods as sustainable ground improvement techniques, bioclogging, defined as the reduction in hydraulic conductivity of soils caused by microbial activities, has been considered as an alternative to the chemical grout techniques for its economic advantages and eco-friendliness of microbial by-products. This study investigated the feasibility of bioaugmentation and biostimulation methods to induce fermentation-based bioclogging effect in coarse sands. In the bioaugmentation experiments, effects of various parameters and conditions, including grain size, pH, and biogenic gas generation, on hydraulic conductivity reduction were examined through a series of column experiments while Leuconostoc mesenteroides, which produce an insoluble biopolymer called dextran, was used as the model bacteria. The column test results demonstrate that the accumulation of bacterial biopolymer can readily reduce the hydraulic conductivity by three-to-four orders of magnitudes or by 99.9-99.99% in well-controlled environments. In the biostimulation experiments, two inoculums of indigenous soil bacteria sampled from waterfront embankments were prepared and their bioclogging efficiency was examined. With one inoculum containing species capable of fermentation and biopolymer production, the hydraulic conductivity reduction by two orders of magnitude was achieved, however, no clogging was found with the other inoculum. This implies that presence of indigenous species capable of biopolymer production and their population, if any, play a key role in causing bioclogging, because of competition with other indigenous bacteria. The presented results provide fundamental insights into the bacterial biopolymer formation mechanism, its effect on soil permeability, and potential of engineering bacterial clogging in subsurface.