• 대한기계학회논문집
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• 제19권7호
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• pp.1604-1618
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• 1995

In the process of mechanical assembly design, assembly modeling systems have been used mainly for the design verification before manufacturing by enabling to check the interference and/ or the dynamic and kinematic performance. However, the conventional assembly modeling systems have a shortcoming that they can not be used in the initial design stage but can be used only after the design is fully completed. In other words conventional assembly modeling systems provide bottom-up modeling which means that the detailed modeling of components must precede the definition of relationships between them. To resolve this problem, an assembly modeling system is proposed to provide a top-down modeling environment in which components and assembly can be modeled simultaneously. To this end, an assembly data structure suitable for top-down assembly modeling has been established. Feature positioning Module(FPM) using geometric constraints has been also developed. The Sekective Solving Method proposed for FPM is based on the priority between the constraint equations and enables the designer's intent expressed by geometric constraints to be maintained throughout the whole modeling process. Finally, the feature based modeling technique using two-level features has been developed. Two-level features include an abstract model and a detailed model in a merged form in non-manifold data frame.

• 한국CDE학회논문집
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• 제7권1호
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• pp.42-56
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• 2002

Presented in this study is a top-down functional requirement analysis procedure and the desired functionalities for PDM system development, and the benefits of top-down approach over a conventional bottom-up approach is also shown. For the purpose of top-down requirement analysis for PDM system, this study proposes 4P modeling view. 4P modeling view is defined as a modeling perspective for classifying functional requirements and integrating product-related information objects that must be man-aged within PDM systems. Based on 4P modeling templates, benchmarking analysis of commercially major PDM products is conducted and as a result of this analysis, this study suggests desired functionalities for PDM system.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.108-109
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• 2019

Top-down construction is a useful method of utilizing the working space, economic benefits and shorten the construction period. Precision construction of the elevator core is very important for safety of the top-down structure. In this study, the layout system for the field-BIM(Building Information Modeling) was used to precisely construct the elevator core in the basement and the ground. Through the layout system, it was possible to process the construction status, review the design results and construction errors, and confirm whether there is or not within the construction error range for elevator installation.

• International Journal of CAD/CAM
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• 제7권1호
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• pp.81-89
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• 2007

As the modular production is an important issue in globalized manufacturing industries, sub modules or parts of the final product are provided by many suppliers. Some part suppliers design their own products for themselves. In some cases, part supplier may provide the same type product to multiple 1-tier companies. Because all suppliers and 1-tier companies can not use the same CAD system in general case, the engineering change in the CAD model of one company could not propagate to related CAD models of other companies directly. Although they use the same CAD system, it is hard to share their CAD model with each other because of company security policy. In this paper, the neutral reference model, which consists of the neutral skeleton model and the external reference model, is proposed to apply a global top-down modeling approach to collaborating companies.

• 한국CDE학회논문집
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• 제5권4호
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• pp.359-372
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• 2000

Current CAD systems are good enough to be used as a tool to manipulate three-dimensional shapes. This is a very important capability to be owned by a design tool because a major portion of designers'activities is spent on the shape manipulation in the design detailing process. However, the whole design process involves a lot more than the, shape manipulation. Currently, these remaining tasks, mostly logical reasoning process for the function realization together with structure decomposition in the top-down manner, are processed in the designer's brain. To support the top-down functional design process of a mechanical product, a system integrating the functional, structural and geometrical aspects of a product design in a unified environment is presented. Using this system, a designer can perform function decomposition, structure decomposition, and geometry detailing, and function verification activities in parallel and the whole design process it modeled resultantly. Once the whole design process is modeled, any redesign task can be automatically performed with the verification of the desired functions.

• 디지털융복합연구
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• 제9권6호
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• pp.27-37
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• 2011

본 연구에서는 에너지 관리 시스템의 기능 요건을 정립하기 위한 하향식 기능 분석 절차를 제안하고 바람직한 기능 요구사항들을 도출하였다. 하향식 기능 분석을 위해 벤치마킹 대상인 에너지관리 시스템 제품들이 제공하는 공통된 기능들을 추출하고 이들을 기능 그룹 단위로 집합하여 7개의 서브시스템으로 분화하고 각 서브시스템 내에서 제공해야 할 기능들을 분류하여 비교용 템플리트를 만들었다. 벤치마킹은 이 비교용 템플리트에 의거하여 각 상용 제품에서 제공하는 기능들을 분류하여 기능 제공 유무를 기입하는 방법으로 수행되었다. 벤치마킹의 결과로 에너지 관리 시스템이 갖추어야 할 바람직한 기능들을 추출하여 이를 상세하게 설명하였다. 이 연구의 결과는 에너지관리 시스템을 개발하거나 도입하려는 관련자들에게 에너지 관리 시스템이 갖추어야 할 필요 기능에 관한 유용한 정보를 제공한다.

• 대한전자공학회논문지SD
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• 제44권4호
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• pp.103-109
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• 2007

본 논문은 최근에 많이 연구되고 있는 PLL 기반의 fractional-N 주파수 합성기에 관하여 SIMULINK 및 Verilog-a를 사용하여 모델링하는 방법론에 대하여 설명한다. 전통적으로 PLL 설계에 적용되는 바텀-업(bottom-up) 방식의 트랜지스터 레벨설계와 함께 탑-다운(top-down) 방식의 설계를 병행하여 적용함으로써 트랜지스터 레벨의 회로설계에 걸리는 시간을 크게 절약하고 SoC의 IP로서 아날로그 부분과 디지털부분이 같이 검증될 수 있는 방안을 고려하고자 한다. 이를 위하여 시스템의 동작여부를 빠르게 파악하고 top level에서의 검증이 용이한 SIMULINK 모델링과 트랜지스터 레벨과의 호환을 통해 블록 단위의 검증이 가능한 Verilog-a 모델링의 비교를 수행함으로서 효과적인 설계 방법을 제시한다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권5호
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• pp.462-469
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• 2005

A top-down approach is known to be a useful and effective technique for the design and analysis of metabolic systems. In this Study, we have constructed a grouped metabolic network for Lactococcus lactis under aerobic conditions using grouped enzyme kinetics. To test the usefulness of grouping work, a non-grouped system and grouped systems were compared quantitatively with each other. Here, grouped Systems were designed as two groups according to the extent of grouping. The overall simulated flux values in grouped and non-grouped models had pretty similar distribution trends, but the details on flux ratio at the pyruvate branch point showed a little difference. This result indicates that our grouping technique can be used as a good model for complicated metabolic networks, however, for detailed analysis of metabolic network, a more robust mechanism Should be considered. In addition to the data for the pyruvate branch point analysis, Some major flux control coefficients were obtained in this research.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.180-180
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• 2021

Recently, structural damage and defect has occurred in the H-beam backfill installation part of Top-Down construction method. In order to secure structural safety and usability in the adjacent section of the backfilling method, It turns out that it is necessary to analyze by dividing into various cases. The H-beam backfill installation section is divided into the case of adding a vertical plate inside the slab, adding a shear stud, adding a reinforcing bar, changing the thickness of the pressure plate, and filling the H-beam backfill with mortar. Ansys modeling was performed and an appropriate solution was suggested by analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.222-223
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• 2010

TOP245P driver IC modeling technique are proposed for the LED Driver design. Analog behavioral model of TOP245P IC including the shunt regulator, under-voltage(UV) detection, over-voltage(OV) shut-down and SR flip-flop is developed by using PSPICE. The averaged-model and switching-model is applied to the LED driver simulation. The simulation results by the proposed TOP245P IC modeling technique are in good agreement with that in the data sheet and an experiment data.