• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5579-5587
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• 2013

Research indicates that a small population of cancer cells is highly tumorigenic, endowed with the capacity for self-renewal, and has the ability to differentiate into cells that constitute the bulk of tumors. These cells are considered the "drivers" of the tumorigenic process in some tumor types, and have been named cancer stem cells (CSC). Epithelial-mesenchymal transition (EMT) appears to be involved in the process leading to the acquisition of stemness by epithelial tumor cells. Through this process, cells acquire an invasive phenotype that may contribute to tumor recurrence and metastasis. CSC have been identified in human head and neck squamous cell carcinomas (HNSCC) using markers such as CD133 and CD44 expression, and aldehyde dehydrogenase (ALDH) activity. Head and neck cancer stem cells reside primarily in perivascular niches in the invasive fronts where endothelial-cell initiated events contribute to their survival and function. Clinically, CSC enrichment has been shown to be enhanced in recurrent disease, treatment failure and metastasis. CSC represent a novel target of study given their slow growth and innate mechanisms conferring treatment resistance. Further understanding of their unique phenotype may reveal potential molecular targets to improve therapeutic and survival outcomes in patients with HNSCC. Here, we discuss the state-of-the-knowledge on the pathobiology of cancer stem cells, with a focus on the impact of these cells on head and neck tumor progression, metastasis and recurrence due to treatment failure.

• 한국수산과학회지
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• 제38권5호
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• pp.331-341
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• 2005

Distribution of anchovy (Engraulis japonica) eggs and larvae was studied in the southwestern sea of Korea in July and November, 2001. Anchovy eggs were found mainly in the oceanic fronts of the northern sea area which were formed in the offshore area of Chuja Is. Bogil Is. and Chungsan Is. from west to east. Anchovy eggs were also found in the surrounding sea of Cheju Is. in the southern sea front area. The waters were highly heterogeneous and the water masses were bordered based on temperature $(10.8-26.4^{\circ}C)$ and salinity (28.9-33.7 psu). The anchovy eggs were mostly found outside of the China Coastal Water, where salinity was below 31 psu. The anchovy eggs were not found in November. Abundance of the anchovy larvae were higher in July than November. Temperature ranged from $10.8^{\circ}C\;to\;25.9^{\circ}C\;and\;15.9^{\circ}C\;to\;20.5^{\circ}C$, and salinity ranged from 28.9psu to 34.1psu and 33.2psu to 34.1psu in July and November, respectively. Non-swimmable larvae were found throughout the whole area of the southwestern sea of Korea. The area beyond the oceanic front had anchovy eggs dispersed from the spawning grounds to offshore. Dispersion pattern showed that the eggs were transported from the spawning grounds with a process of advection and diffusion based on the flow pattern which were caused by winds. Distribution pattern of the anchovy eggs and larvae may be used for the prediction of oceanic currents in each area.

• 한국수산과학회지
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• 제40권6호
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• pp.394-410
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• 2007

Anchovy spawn from the end of May to mid-October, when the water temperature is $14.8-27.2\;^{\circ}C$ and the salinity is 26.0-33.6 psu. The main spawning season is between July to August, when the water temperature is $21.7-27.2\;^{\circ}C$ and the salinity is between 26.0-32.2 psu. The main spawning grounds of anchovy are coastal areas shallower than 50 m around the islands located in the Jeju Strait. Anchovy larvae are distributed near the fronts between Chuja-do, Jangsu-do, Yeoseo-do, and the open sea rather than in the spawning grounds. Anchovy eggs and larvae density increased in accordance with the high level of $Chlorophyll-{\alpha}$ during the summer season (July-August). In terms of the suspended sediment (SS) levels along the northern coast of the Jeju Strait, high densities of anchovy eggs (12.0-18.0 mg/L) were observed, mainly in the area affected by the coastal waters of the southern sea with high SS levels, while larvae (10.0-19.0 mg/L) tended to be distributed over a wide area with high SS levels, including the open sea. In terms of the dissolved oxygen (DO) content, eggs (5.4-6.8 mg/L) were observed in coastal areas with a high DO content, while larvae (4.2-6.4 mg/L) were distributed widely in areas with a relatively low DO content, from the southern coast to the open sea.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제19권2호
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• pp.197-215
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• 2015

Modeling water flow in variably saturated, porous media is important in many branches of science and engineering. Highly nonlinear relationships between water content and hydraulic conductivity and soil-water pressure result in very steep wetting fronts causing numerical problems. These include poor efficiency when modeling water infiltration into very dry porous media, and numerical oscillation near a steep wetting front. A one-dimensional finite element formulation is developed for the numerical simulation of variably saturated flow systems. First order backward Euler implicit and second order Crank-Nicolson time discretization schemes are adopted as a solution strategy in this formulation based on Picard and Newton iterative techniques. Five examples are used to investigate the numerical performance of two approaches and the different factors are highlighted that can affect their convergence and efficiency. The first test case deals with sharp moisture front that infiltrates into the soil column. It shows the capability of providing a mass-conservative behavior. Saturated conditions are not developed in the second test case. Involving of dry initial condition and steep wetting front are the main numerical complexity of the third test example. Fourth test case is a rapid infiltration of water from the surface, followed by a period of redistribution of the water due to the dynamic boundary condition. The last one-dimensional test case involves flow into a layered soil with variable initial conditions. The numerical results indicate that the Crank-Nicolson scheme is inefficient compared to fully implicit backward Euler scheme for the layered soil problem but offers same accuracy for the other homogeneous soil cases.

• 한국해양학회지
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• 제17권2호
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• pp.33-40
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• 1982

한반도 남동해역의 해황조건을 수온전선의 변동이라는 관점에서 조사연구 하였다. 수온전선의 변동형태는 대단히 복잡하지만 크게 3개형으로 나누어진다. 제 1 형은 동해안과 평행하게 북쪽으로 연장된 형으로 연안쪽에 좁은 냉수대를 끼고 있으며 제 2 형은 대략 36 N 위도선에 나랑하게 동서방향으로 연장되어 있고, 제 3 형은 불규칙하게 분포하는 형으로 전기압성 냉수괴와 고기압성 난수괴가 거의 비슷하게 여기 저기 분포하기 때문에 나타난 형이다. 제 1 형은 대마난류와 한류 등 두 해류가 모두 발단한 때나 또는 어느 한쪽만의 발단에 의해서도 강화될 수 있다. 한편 이들 전선의 형태는 바람의 분포와도 밀접한 관련이 있는 것 같다. 겨울철 북풍성분의 바람이 강해지면 제 1 형은 약해지고 제 2 형이 뚜렷해지며 여름철 남풍성분의 바람이 강해지면 제 1 형이 강화되는 경향이 있다.

• 대한지리학회지
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• 제42권1호
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• pp.1-14
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• 2007

본 연구에서는 우리나라 육상 국지 예보 구역을 대상으로 예보 정확도를 분석하였다. 연구 기간 동안 평가 요소별 정확도는 강수 유무가 가장 낮았고 하늘 상태가 가장 높았다. 지역적으로 예보 정확도는 강원도에서 가장 낮았으며 경상남도와 경상북도에서 높았다. 계절별 예보 정확도의 만점 빈도는 겨울에 가장 높았고 여름에 가장 낮았다. 예보 정확도가 낮은 날의 기압 배치형을 분석했을 때 여름철에는 정체전선형 기압 배치에서 강수 유무의 예보 정확도가 낮았다. 가을과 겨울에는 한대 고기압 확장형 기압 배치에서 기온 예보의 정확도가 크게 낮아지는 경우가 많았다. 봄과 가을의 이동성 고기압형 기압 배치에서는 날씨가 급격하게 변하여 예보 정확도가 낮았다. 예보 정확도가 가장 낮은 지역인 영동 지역의 상층 850hPa 고도의 풍향 자료와 예보 정확도를 비교하여 분석한 결과, 최저 및 최고 기온은 서풍일 때, 강수 유무의 경우 동풍일 때 예보 정확도가 낮았다.

• Structural Engineering and Mechanics
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• 제16권4호
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• pp.493-517
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• 2003

Attempts at improving beam-column joint performance has resulted in non-conventional ways of reinforcement such as the use of the crossed inclined bars in the joint area. Despite the wide accumulation of test data, the influence of the crossed inclined bars on the shear strength of the cyclically loaded exterior beam-column joints has not yet been quantified and incorporated into code recommendations. In this study, the investigation of joints has been pursued on two different fronts. In the first approach, the parameters that influence the behaviour of the cyclically loaded beam-column joints are investigated. Several parametric studies are carried out to explore the shear resisting mechanisms of cyclically loaded beam-column joints using an experimental database consisting of a large number of joint tests. In the second approach, the mechanical behaviour of joints is investigated and the equations for the principal tensile strain and the average shear stress are derived from joint mechanics. It is apparent that the predictions of these two approaches agree well with each other. A design equation that predicts the shear strength of the cyclically loaded exterior beam-column joints is proposed. The design equation proposed has three major differences from the previously suggested design equations. First, the influence of the bond conditions on the joint shear strength is considered. Second, the equation takes the influence of the shear transfer mechanisms of the crossed inclined bars into account and, third, the equation is applicable on joints with high concrete cylinder strength. The proposed equation is compared with the predictions of the other design equations. It is apparent that the proposed design equation predicts the joint shear strength accurately and is an improvement on the existing code recommendations.

• 대한기계학회논문집A
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• 제25권8호
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• pp.1294-1301
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• 2001

In order to reduce the time and cost for assembly, automobile speaker grills have been injection molded with door trims or map pockets in one piece recently. However, several defects such as short shots or air traps can easily occur due to the decreased fluidity of the melting polymer according to the excessive heat transfer to the mold. Therefore, it is necessary to optimize the resin feed system and predict possible defects by CAE analysis. However it is not possible to obtain exact analysis results for the speaker grill by using general shell elements since the heat transfer in the thickness direction which is the dominant factor of the filling stage can not be considered. Therefore, there have been several efforts to simulate the injection molding nature of the speaker grill by using shell elements with an effective thickness which is smaller than the actual thickness of the part. Two empirical values have been recommended for the effective thickness in real practice. One is 50∼70% of the thickness of the speaker grill and another is the gap distance between the adjacent holes. In this paper, CAE analyses of a map pocket with a speaker grill were conducted using shell elements with both of these recommended effective thicknesses, and the predicted flow fronts were compared with the findings from injection molding experiments. The commercial code MOLDFLOW was used for injection molding analysis and an 850 ton injection molding machine was used for experiments.

• 산업경영시스템학회지
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• 제40권4호
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• pp.211-220
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• 2017

The application of the theoretical model to real assembly lines has been one of the biggest challenges for researchers and industrial engineers. There should be some realistic approach to achieve the conflicting objectives on real systems. Therefore, in this paper, a model is developed to synchronize a real system (A discrete event simulation model) with a theoretical model (An optimization model). This synchronization will enable the realistic optimization of systems. A job assignment model of the assembly line is formulated for the evaluation of proposed realistic optimization to achieve multiple conflicting objectives. The objectives, fluctuation in cycle time, throughput, labor cost, energy cost, teamwork and deviation in the skill level of operators have been modeled mathematically. To solve the formulated mathematical model, a multi-objective simulation integrated hybrid genetic algorithm (MO-SHGA) is proposed. In MO-SHGA each individual in each population acts as an input scenario of simulation. Also, it is very difficult to assign weights to the objective function in the traditional multi-objective GA because of pareto fronts. Therefore, we have proposed a probabilistic based linearization and multi-objective to single objective conversion method at population evolution phase. The performance of MO-SHGA is evaluated with the standard multi-objective genetic algorithm (MO-GA) with both deterministic and stochastic data settings. A case study of the goalkeeping gloves assembly line is also presented as a numerical example which is solved using MO-SHGA and MO-GA. The proposed research is useful for the development of synchronized human based assembly lines for real time monitoring, optimization, and control.

• 한국중재학회지:중재연구
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• 제27권3호
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• pp.95-107
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• 2017

Mongolian government enacted the Foreign Trade Arbitration Law to modernize the practice of commercial arbitration. Nevertheless, the Foreign Trade Arbitration Trade Law fell short on a number of fronts and arbitration itself remained a distant second option to litigation within Mongolia. Law on Arbitration of 2003 aimed to modernize the Mongolian arbitration framework so that it would mirror the UNCITRAL Model Law on International Commercial Arbitration. At the same time, the Law on Arbitration 2003 made a conscious decision to deviate from international norms with respect to certain aspects in order to accommodate for the unique circumstances and characteristics of Mongolia. For example, unlike its UNCITRAL counterpart, the Law on Arbitration of 2003 did not include an exhaustive list of grounds for refusing the recognition and enforcement of arbitral awards. In that sense, the Law on Arbitration of 2003 was a resounding success and a drastic improvement on the Foreign Trade Arbitration Law. These factors convinced the Mongolian government to once again revise its arbitration law. This process, which started in 2008 with the help of foreign law firms and institutions, ultimately culminated in the Law of Arbitration of 2017. The chief objective of the Law of Arbitration of 2017 was to more closely adhere to preexisting international norms on arbitration such as the Model Law on International Commercial Arbitration, and there is no question that Mongolia has succeeded in doing so. This article thus concludes by explaining some of the noteworthy improvements made by the 2017 revisions, and by noting that Mongolia is now equipped with a truly international legal framework for arbitration.