• 방사성폐기물학회지
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• 제21권4호
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• pp.465-479
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• 2023

To ensure the safety of disposal facilities for radioactive waste, it is essential to quantitatively evaluate the performance of the waste disposal facilities by using safety assessment models. This paper addresses the development of the safety assessment model for the underground silo of Wolseong Low-and Immediate-Level Waste (LILW) disposal facility in Korea. As the simulated result, the nuclides diffused from the waste were kept inside the silo without the leakage of those while the integrity of the concrete is maintained. After the degradation of concrete, radionuclides migrate in the same direction as the groundwater flow by mainly advection mechanism. The release of radionuclides has a positive linear relationship with a half-life in the range of medium half-life. Additionally, the solidified waste form delays and reduces the migration of radionuclides through the interaction between the nuclides and the solidified medium. Herein, the phenomenon of this delay was implemented with the mass transfer coefficient of the flux node at numerical modeling. The solidification effects, which are delaying and reducing the leakage of nuclides, were maintained the integrity of the nuclides. This effect was decreased by increasing the half-life and the mass transfer coefficient of radionuclides.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.49-49
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• 2004

고도화로 정밀해진 현대 과학기기에는 여러 가지 전자 팩키징 제품들이 쓰이고 있으나 이 제품들은 여러 가지 파손인자들의 영향 때문에 고유의 수명을 다하지 못하고 고장이 발생하게 된다. 전자부품 실장에 이용되는 솔더 조인트의 열화에 관련되는 열 피로와 이온 마이그레이션(Migration) 현상이 솔더 조인트의 신뢰성에 영향을 미치는 가장 중요한 인자로 알려져 있고 이러한 인자 이외에도 여러 가지 요인들이 복합적으로 작용하여 솔더의 접합부분에 피로파괴를 일으킨다.(중략)

• 한국통신학회논문지
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• 제23권9A호
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• pp.2230-2239
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• 1998

Recently, mobility support of connectionless mobile ATM data service has been mainly studied in wireless ATM communication network. this paper shows the network model for the mobility support of connectionless data service in ATM network, and proposes the methods to minimize COIP (care of IP address) acquisition processing time for MH(mobile host)migration. Th echaracteristics of proposed methods, COIP acquisition probability and IP data communication sequence of proposed model, are discussed in this paper.

• Interaction and multiscale mechanics
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• 제1권2호
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• pp.191-209
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• 2008

In this paper, we model grain boundary evolution based on a multiple level set method. Grain boundary migration under a curvature-induced driving force is considered and the level set method is employed to deal with the resulting topological changes of grain structures. The complexity of using a level set method for modeling grain structure evolution is due to its N-phase nature and the associated geometry compatibility constraint. We employ a multiple level set method with a predictor-multicorrectors approach to reduce the gaps in the triple junctions down to the grid resolution level. A ghost cell approach for imposing periodic boundary conditions is introduced without solving a constrained problem with a Lagrange multiplier method or a penalty method. Numerical results for both uniform and random grain structures evolution are presented and the results are compared with the solutions based on a front tracking approach (Chen and Kotta et al. 2004b).

• Korea-Australia Rheology Journal
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• 제14권4호
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• pp.203-207
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• 2002

Particle-particle interaction is of great importance in the study of suspension rheology. In this research we have investigated the hydrodynamic interaction between two identical cylinders in viscoelastic fluids numerically as a model problem for the study of viscoelastic suspension. We confine two neutrally buoyant cylinders between two parallel plates and impose a shear flow. We determine the migration velocity of two cylinders. The result shows that cylinders move toward or away from each other depending upon the initial distance between them and that there is an equilibrium distance between two cylinders in viscoelastic fluids regardless of the initial distance. In the case of Newtonian fluid, there is no relative movement as expected. The results partly explain the chaining phenomena of spherical particles in shear flows of viscoelastic fluids.

• 한국인구학
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• 제22권1호
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• pp.153-173
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• 1999

광역도시내 대도시와 신도시는 경제적인 유기체임에도 불구하고 임의적인 행정구역으로 분할되어 있다. 이 결과 대도시는 신도시 주민들을 위하여 막대한 재원을 투자하여 도시기반시설을 건설하여야 하나, 상주인구의 감소로 재원부족이라는 어려움에 빠지게 된다. 본 연구는 1990년 미국 센서스 1% 자료를 이용하여 53개 광역도시내 인구이동을 분석하여 대도시가 도시기반시설에 투자를 하면 할수록 신도시로 대도시 인구가 빠져나가는 "신도시 주민의 대도시 찰취가설"을 입증하였다. 결국 광역도시내에 상이한 지방정부가 존재하는 경우 지방정부서비스 공급은 티부이론이 제시하는 효율성을 달성하지 못하기 때문에 광역도시내 정부 서비스의 공급은 사무엘슨 방식의 통합적 제공이 필요하다. 제공이 필요하다.

• 전기학회논문지
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• 제57권9호
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• pp.1636-1641
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• 2008

In this study, we introduce a new approach to Parallel Genetic Algorithms (PGA) which combines AHFCGA with crossover operator. As to crossover operators, we use three types of the crossover operators such as modified simple crossover(MSX), arithmetic crossover(AX), and Unimodal Normal Distribution Crossover(UNDX) for real coding. The AHFC model is given as an extended and adaptive version of HFC for parameter optimization. The migration topology of AHFC is composed of sub-populations(demes), the admission threshold levels, and admission buffer for the deme of each threshold level through succesive evolution process. In particular, UNDX is mean-centric crossover operator using multiple parents, and generates offsprings obeying a normal distribution around the center of parents. By using test functions having multimodality and/or epistasis, which are commonly used in the study of function parameter optimization, Experimental results show that AHFCGA can produce more preferable output performance result when compared to HFCGA and RCGA.

• Archives of Pharmacal Research
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• 제21권1호
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• pp.30-34
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• 1998

The ethanol extracts of Opuntia ficus-indica fructus (EEOF) and Opuntia ficus-indica stem (EEOS) were prepared and used to evaluate the pharmacological effects of cactus. Both the extracts inhibited the writhing syndrome induced by acetic acid, indicating that they contains analgesic effect. The oral administrations of EEOF and EEOS suppressed carrageenan-induced rat paw edema and also showed potent inhibition in the leukocyte migration of CMC-pouch model in rats. Moreover, the extracts suppressed the release of $\beta$-glucuronidase, a lysosomal enzyme in rat neutrophils. It was also noted that the extracts showed the protective effect on gastric mucosal layers. From the results it is suggested that the cactus extracts contain anti-inflammatory action having protective effect against gastric lesions.

• 한국정보처리학회논문지
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• 제7권3호
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• pp.953-961
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• 2000

In this paper, we propose the algorithm which solve synchronization problem happened migrating service objects. Load imbalance is occurred due to allocate different amount of load to be proposed to each node in distribute system. To solve this problem, the service objects have to be migrated from heavily loaded node to lightly loaded node. And in such a process, the synchronization problem may occur when client request a service object migrated incompletely. Therefore, we describe the environment of executing service objects, the importer/exporter/trader model compatible with migration of service objects, and appropriate migration algorithm, Finally, we analyze the conditions of problems, and propose the solution of each situations. Also, the performance advantages of using proposed algorithms are quantified through a simulation study.

• 한국멀티미디어학회논문지
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• 제8권3호
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• pp.398-412
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• 2005

레거시 시스템을 새로운 하드웨어 플랫폼과 새로운 소프트웨어 개발 패러다임에 맞도록 이주하려는데 대한 관심이 증가하고 있다. 그 이유는 레거시 시스템의 유지보수에 많은 비용이 들고 기존 시스템에 대한 문서 정보가 부족하다는데 있다. 레거시 시스템을 새로운 시스템을 변환하기 위해 스크린 스크래핑, 래핑, 부분 변환, 재개발 등등의 여러 다양한 접근법들과 도구, 그리고 방법론들이 제시되어왔다. 그러나 이러한 접근법들은 대부분이 코드 변환 혹은 일부 모델 변환 수준이기 때문에 아키텍처나 요구사항 수준에서의 변환까지는 체계적으로 제시하지 못하였다. 따라서, 본 논문에서는 이러한 한계점을 극복하기 위하여 아키텍처와 요구사항 단계까지 적용할 수 있는 3차원 공간 개념을 적용한 메타 모델 기반의 접근법을 제시하고자한다. 이러한 통합 모델은 재 공학에 있어서 역 공학 단계인 코드에서 아키텍처 그리고 순 공학 단계인 아키텍처에서 코드로의 자연스러운 변환 혹은 협력 진화(Co-evoluton)를 유도한다.