• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.243-250
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• 2006

A recursive relationship is a relationship among entities of the same class. N : M recursive relationships can be used to represent bills of materials. A bill of materials is a special data structure that occurs frequently in manufacturing applications. This data structure is a hierarchy. Most business dimensions have a hierarchical structure. In this study, a design of a hierarchical dimension of the bill of materials type is carried out. As with other N : M relationships, an intersection table that shows pairs of related rows is created, and this table is transformed into a dimension in the OLAP(OnLine Analytical Processing) model. This transformation consists of two tasks: (1)replacing the first column of the intersection table with the lowest level of the dimension: and (2)replacing the second column of the table with the only upper level of the dimension. A case multidimensional information system using the hierarchical dimension is also developed.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.7-7
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• 2018

1차원 하수관로 해석 모형과 2차원 지표면 유출 해석 모형을 연계한 1D-2D 결합 도시침수 모델은 도시지역의 유출 현상과 침수 모의에 널리 이용되고 있다. 그러나 도시 지역의 복잡한 지형이 지표면 유출 흐름에 미치는 영향을 보다 자세히 파악하기 위해서는 보다 높은 해상도의 지형자료를 활용한 모의가 필요하다. 본 연구에서는 도시침수 해석을 위한 1D-2D 결합 하이브리드(Hybrid) 병렬화 코드(H12)를 개발하여 넓은 도시 유역에 대해서 고해상도 지형자료를 활용한 모의가 유역단위로 가능하도록 하였다. H12는 Open Multi-Processing(OpenMP)와 Message Passing Interface(MPI) 병렬 계산을 동시에 수행하여 매우 넓은 지역에 대해서도 도로의 형태를 확인 할 수 있는 수준의 고해상도 침수 해석 모의가 가능하다. 또한 도시지역의 복잡한 지형을 자세히 재현하고 계산의 효율을 높이기 위하여 격자세분화 기법이 적용되었다. H12의 적용성을 평가하기 위하여 미국 텍사스 알링턴 지역의 Johnson Creek 유역(${\sim}40km^2$)유역에 대한 시범 모의를 수행하였으며 도시유역의 지형을 표현하기 위하여 1m 해상도의 LiDAR자료를 사용하여 침수발생시 보다 자세한 유출수의 흐름을 해석할 수 있도록 하였다. 모의 결과 하이브리드 병렬 계산은 순차적 계산에 비하여 최고 79배 이상 빠른 계산속도 효율 향상을 보여주었으며, OpenMP나 MPI를 단독으로 사용하는 것에 비하여 더욱 효율적인 계산속도 효율 향상을 보여주었다.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.381-395
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• 2008

Purpoose: For decades dental implants have been used widely in the field of prosthetic dentistry. However there is confusion when establishing treatment plans in cases where some teeth are remained but an insufficient number of implants can be used due to limited anatomical status and ecomomical problems. Many clinicians have tried to connect natural teeth and implants, and it still has controversy. But, there have been few studies on mechanical analysis of connecting natural teeth and implants with konus telescopic removable partial dentures. The purpose of this study was to analyze the stress distribution of prosthesis, abutment and alveolar bone when teeth and implants were connected with the konus telescopic denture, by means of 3-dimensional finite element analysis. Material and methods: The assumption of this study was that there were 2 mandibular canine (11 mm in length, 4 mm in diameter) and 2 implants(10 mm in length, 4 mm in diameter) which are located in the second premolar region. The mandible, teeth, implants, abutments, and connectors are modeled, and analyzed with the commercial software, ANSYS Version 8.1(Swanson, Inc., USA). The control group used implants instead of natural teeth. 21038 elements, 23544 nodes were used in experimental group and 107595 elements, 21963 nodes were used in control group, Stress distribution was evaluated under 150 N vertical load on 3 experimental conditions - between teeth and implants (Load case 1), posterior to implants (Load case 2), between natural teeth (Load case 3). Results: 1. In all load cases, higher von mises stress value was observed in the experimental group. 2. Maximum von miss stress observed in all load cases and all locations were as follows ; a. 929.44 Mpa in the experimental group, 640.044 Mpa in the control group in outer crown and connector - The experimental group showed 1.45 times high value compared with the control group. b. 145,051 Mpa in the experimental group, 142.338 Mpa in the control group in abutment - The experimental group showed 1.02times high value compared with the control group. c. 32.489 Mpa in the experimental group, 25.765 Mpa in the control group in alveolar bone - The experimental group showed 1.26times higher value compared with the control group. 3. All maximum von mises stress was observed in load case 2, and maxim von mises stress in alveolar bone was 32.489 Mpa at which implant failure cannot occur. 4. If maximum von mises stress is compared between two groups, the value of the experimental group is 1.02 times higher than the control group in abutment, 1.26 times higher than the control group in alveolar bone. Conclusion: If natural teeth and implants are connected with the konus telescopic denture, maximum stress will be similar in abutment, 1.26 times higher in alveolar bone than the control group. With this result, there may be possible to make to avoid konus telescopic dentures where natural teeth and implants exist together.

• Journal of Power System Engineering
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• v.7 no.1
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• pp.14-19
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• 2003

A diesel engine has been widely used for ship and industry power because it has many merits of high thermal efficiency, reliability and durability. However its exhaust gas is harmful to human and air environment. Reducing the hurtful exhaust gas emissions, the study of the gas flow in the inlet and exhaust manifold is in progress in the world. In this paper we modeled the gas flow as one dimensional isentropic flow to predict the gas flow in the exhaust manifold. The method of characteristics was used for the model calculation, and the calculated results were compared with the experimental ones.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.28-34
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• 2008

가스-액체 이젝터에 관한 수치해석은 3차원 CFD 모델로 수행하였다. 본 논문에서는 이젝터의 유동특성과 질량전달특성에 대한 작동조건과 이젝터의 기하학적 모형의 영향에 관한 연구를 수행하고자 한다. CFD 결과 실험 데이터에 의하여 검증되었으며, 유동 분석과 이젝터 성능의 예측 또한 실행되었다. 작동상태의 변화는 0.2 $\sim$ 1.2 범위에서 가스-액체 유량비를 변화시킴으로서 주어진다. 혼합관의 $L_M/D_M$이 4 $\sim$ 10의 범위에서 변화를 주었다. CFD 연구는 길이와 직경비가 5.5일 때 체적 유량전달계수는 가스 유량이 증가함에 따라 증가한다는 것을 나타낸다. 동시에 $L_M/D_M$가 4일 때 체적유량전달계수는 기체-액체 유량비가 0.6에서 최대치에 도달한다. 또한, 체적 유량전달계수는 혼합 튜브길이가 증가함에 따라 감소한다.

• Korean Journal of Social Welfare
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• v.53
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• pp.257-283
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• 2003

The main objective of this study is to examine antecedents and outcome of organizational cynicism. This paper focuses on organizational commitment of social worker as outcome variable. Thus, this study attempts to examine structural relation of variables of organizational level(personnel management), job level(job characteristics), and individual level(level of self-control) on the level of organizational commitment, with special concern about the mediating effect of organizational cynicism. The study conducted mail survey and collected information for data analysis from 330 social workers working at 173 social welfare organizations in Seoul and Kyong-gi area, The study used structural equation modeling(SEM) method for analyzing the constructed model. Main results are as follows: (1) evaluation about personnel management is negatively related to organizational cynicism; (2) evaluation about job characteristics is negatively related to organizational cynicism; (3) evaluation about self-control is negatively related to organizational cynicism; (4) organizational cynicism exerts negative effect on the level of organizational commitment; and (5) evaluation about personnel management, evaluation about job characteristics, and evaluation about self-control exerts positive effect on the level of organizational commitment. Among the results of this study, this paper focuses on the function of personnel management system on organizational cynicism. This paper emphasizes that social welfare organizations must make a lot of efforts for making fair personnel system in order to reduce social workers' organizational cynicism and ultimately promote their organizational commitment.

• The Journal of Information Systems
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• v.11 no.1
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• pp.75-103
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• 2002

현대사회는 전통적인 경제체제에서 디지털 경제체제로의 급속한 이전과 더불어 정보기술이 국가발전의 주요 원동력으로 등장하게 되었다. 특히, e-정부의 출현은 기존의 정부서비스에 대한 시공간적 제약을 극복하는 새로운 패러다임으로 간주되고 있다. 본 연구는 e-정부 실현을 위한 대표적인 사례로 KICIT을 중심으로 정보기술의 활용사례와 더불어 EC-Bank를 중심으로 한 지방정부의 사이버 마케팅에 대한 사례연구를 통해 e-정부의 조기 실현을 위한 산업부문의 e-비즈니스화에 대한 하나의 대안으로 소개하였다. e-구미의 모형은 행정, 생활, 산업 차원에서의 네트워크화, 균형과 조화, 부문간의 연계로 시행정의 디지털화, 사이버 정보생활의 실현 및 산업의 e-비즈니스화의 실현을 중심으로 제시하였다. 본 연구에서 KICIT은 중소도시에 집중되어 있는 지역정보센터의 산학관 협력의 모델케이스로 효율적으로 운영되고 있음을 확인할 수 있었다. 이제는 구미지역 기업체와 연구교육기관에서 핵심적인 지원기관으로 지역관련기관과의 보다 유기적인 협력을 계속 유지. 발전해 나가야 할 것이다. 지자체의 사이버 마케팅 사례인 EC-Bank는 정보서비스를 단순히 제공하는 수준인 전자상거래의 초기단계로 사이트 및 콘텐츠 관리의 소홀로 인하여 초기의 목적을 거의 이루지 못한 실정이다. 앞으로 산학관의 친밀한 협력과 e-프로세스의 대혁신을 통해서 새로운 업무활용, 웹기반의 거래처리 및 e-비즈니스 모형의 창출을 위해 계속적으로 노력해야할 것이다.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.125-132
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• 2010

The authors have investigated the acoustic field analysis using the Constrained Interpolation Profile(CIP) Method recently proposed by Yabe. This study has examined the calculation accuracy of the three-dimensional(3-D) acoustic field analysis using the type C CIP method. In this paper we show phase error of type C CIP method and the dependence on the wave-propagation direction in the type C CIP acoustic field analysis, and then demonstrate that it gives less-diffusive results than conventional analysis. Moreover, in comparison between type C-1 CIP, type C-2 CIP, type M CIP and FDTD, reports the memory requirements and calculation time of each method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1154-1166
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• 1991

Optical flow is important not only for determining velocity and trajectory of the object but also for image segmentation and three dimensional information. In this paper an algorithm for segmentation of the optical flow field is presented. This method is based on a pyramid linking method combined with the proposed models. In this method each node contained a model of the flow in the region that it represented regions were combined by taking the model that best fit the union of the two regions. Each node linked to one of its fathers based on the error between the pixels represented by the node and the father's model of its flow. A major problem which has emerged in conventional researchs on optical flow field is sensitive to noise the proposed method is relatively insensitive to noise at the result of computer simulation the pyramid algorithm proposed in this paper seem to have useful properties.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.50-57
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• 2003

In this paper, an automated design and 3-D modeling system of an axial fan and a boss for cooling towers was developed. API and parametric design Provided by a commercial solid-modeler are engaged to automate modeling process. Design data of the boss are assumed to be given by a user with design experiences while the fan from the fan design program using three-dimensional flow analysis. An algorithm avoiding the interferences between fans and a boss is developed. The design data are registered on the database not only to remove duplicate design but also to transfer the data to ERP system.