• 한국정밀공학회지
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• 제13권9호
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• pp.84-93
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• 1996

This paper describes the development of new feature positioning method which embedded into the top-down assembly modeling system supporting conceptual design. In this work, the user provides the geometric constraints representing the position and size of features, then the system calculates their proper solution. The use of geometric constraints which are easy to understand intuitively enables the user to represent his design intents about geometric shapes, and enables the system to propagate the changes automatically when some editing occurs. To find the proper solution of given constraints, the Selective Solving Method in which the redundant or conflict equations are detected and discarded is devised. The validity of feature shapes satisfying the constraints can be maintained by this technique, and under or over constrained user-defined constraints can also be estimated. The problems such as getting the initial guess, controlling the multiple solutions, and dealing with objects of rotational symmetry are also resolved. Through this work, the feature based modeling system can support more general and convenient modeling method, and keeps the model being valid during modifying models.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.521-522
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• 2006

This paper presents behavioral models using SIMULINK and Verilog-a for a PLL based fractional-N frequency synthesizer. The SIMULINK modeling was built in the frequency-time mixed domain whereas the Verilog-a modeling was built purely in the time domain. The simulated results of the two models were verified to show the same performance within the error tolerance. This top-down design method can provide the readiness for the transistor-level design.

• The Journal of Asian Finance, Economics and Business
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• 제8권1호
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• pp.543-550
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• 2021

The purpose of the study is to investigate the simulated effects of the Philippine tax reform, which is called Tax Reform for Acceleration and Inclusion Law, on household income and occupational choice. The study utilized the Family Income Expenditure Survey and tax collection as input to Computable General Equilibrium-Top Down Behavioral Microsimulation approach to determine the effect of Philippine tax reform on household income and occupational choice. The results of the study show that the household income in the Philippines will increase due to the implementation of the Philippine tax reform. Also, the study had found that tax reform results drive the household to shift from being farming entrepreneur to salaried workers since the utility derived from being workers is much higher compared to the utility derived from being entrepreneur. The findings of this research suggest that the Philippine Tax Reform for Acceleration and Inclusion Law is beneficial to the household since their income would increase, which will further result to an increase in their capability to buy goods and services. However, the tax reform would also lead to imbalance between the distribution of numbers of workers across sectors such as entrepreneurial farming, entrepreneurial non-farming, and wage sector.

• 한국공작기계학회논문집
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• 제11권4호
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• pp.68-74
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• 2002

The FD process is analogous to the direct piston extrusion process where the cold feed filament acts as a piston extruding the molten filament from the heated liquefier through a nozzle. The extruded filament is deposited on top of futureless platform, where the liquefier and the nozzle move in X and Y direction control by computer based on the part geometry. After the first layer, the Z platform indexes down and the next layer get deposited on top of the first layer. the layer by layer building process introduces surface problem. This paper describes effect of slice interval of the parts built by fused deposition modelling rapid prototyping system.

• ETRI Journal
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• 제20권2호
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• pp.192-213
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• 1998

The current approaches in Object-Oriented Analysis have limitations on modeling complex real world systems because they require priori knowledge about objects and their interactions before applying them. This may be practical in small systems and systems with clear domain knowledge, but not in large real world systems with unclear domain knowledge. Our approach uses a stepwise refinement technique in a top-down manner to the Object-Oriented Analysis stage with the application of use cases. This approach is especially good for new areas where we do not know all the information in advance. We present the approach with an example of its application to the B-ISDN service modeling and distributed systems.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권1호
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• pp.1-9
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• 2006

We introduce our in-house program, NANOCAD, for the modeling and simulation of carrier transport in nanoscale MOSFET devices including quantum-mechanical effects, which implements two kinds of modeling approaches: the top-down approach based on the macroscopic quantum correction model and the bottom-up approach based on the microscopic non-equilibrium Green’s function formalism. We briefly review these two approaches and show their applications to the nanoscale bulk MOSFET device and silicon nanowire transistor, respectively.

• 한국통신학회논문지
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• 제32권10C호
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• pp.1019-1024
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• 2007

본 논문에서는 무선 랜 시스템용 10비트 20MHz 파이프라인 아날로그-디지털 변환기 설계를 위해서 Verilog-A 언어를 사용하여서 모델링하였다. 변환기내 샘플 / 홀드 증폭기, 비교기, MDAC 및 오차 보정 회로 등의 구성회로들을 각각 모델링해서 모의실험 한 결과 HSPICE를 이용한 모의 실험 시간보다 1/50배로 단축되어서 시스템 모델링에 적합함을 확인하였다.

• 한국IT서비스학회지
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• 제11권1호
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• pp.197-210
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• 2012

This paper presents the ways that can improve the Software Cost Estimation Guidelines in order to replace those that are expected to be abolished at February, 2012, and solve the problems that are being occurred in the current Software Cost Estimation Guidelines. By using multidimensional modeling of OLAP(On-Line Analytical Processing), this paper does three dimensional modeling that considers the product/service view, process view and skill view. Also, it presents the identification method of cost estimation data through the view of each dimension. Furthermore, it defines the software cost estimation process and adapts them into the bottom up estimation and the top down estimation. Finally, it proposes the access of cost estimation data by the multidimensional analysis of OLAP.

• 대한산업공학회지
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• 제42권6호
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• pp.377-385
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• 2016

The previous Adaptive Control of Thought-Rational (ACT-R) cognitive architecture model has a limitation in that it cannot accurately predict human visual search strategy, because time effect, one of important human cognitive features, is not considered. Thus, the present study proposes ACT-R cognitive modeling that contains the impact of time using a revised utility system in the ACT-R model. Then, the validation of the model is performed by comparing results of the model with eye-tracking experimental data and SEEV-T (SEEV-Time; SEEV model which considers time effect) model in "Where's Wally" game. The results demonstrate that the model data fit fairly well with the eye-tracking data ($R^2=0.91$) and SEEV-T model ($R^2=0.93$). Therefore, the modeling method which considers time effect using a revised utility system should be used in predicting the human visual search paradigm when the available time is limited.

• 인터넷정보학회논문지
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• 제23권6호
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• pp.79-86
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• 2022

본 연구는 스마트도시 구축과정에서 시민참여 활성화를 위한 연구동향을 파악하고자 한다. 이를 바탕으로 스마트도시에서 시민참여의 역할과 방향을 제시하고 시민참여를 유인할 수 있는 정책적·산업적·학술적·방향성을 제시하는데 있다. 전 세계적으로 급격하게 진행되는 도시화와 도시인구 증가로 교통, 환경, 에너지 등 각종사회 문제가 도시를 중심으로 확산 및 심화되고 있다. 세계 각국은 이런 도시문제 해결 및 지속가능한 발전을 이루기 위해 스마트도시를 도입하고 있다. 최근에는 인프라 확대 등 스마트도시 건설을 위한 기존의 하향식(Top-Down) 도시계획 방식에서 벗어나 시민들이 직·간접적으로 도시건설 과정에 참여 및 상호작용할 수 있는 상향식(Bottom-Up) 방식으로의 접근이 경주되고 있다. 한편, 국내에서도 국가전략관점에서 스마트도시 건설이 추진되고 있지만, 스마트도시에 대한 일반 시민의 인식과 참여는 낮은 것으로 나타나고 있다. 이런 상황을 극복하기 위해 스마트도시의 구축과정에서 시민참여를 촉진하기 위한 연구가 시급한 상황이다. 따라서 본 연구에서는 스마트도시의 구축과정에서 시민참여를 촉진하기 위한 전략모색을 위해 Scopus DB에서 'Smart City'와 'Participation(Engagement)'가 동시에 포함된 문헌 995건을 수집 후 토픽모델링 기법을 활용하여 관련 연구주제를 유형화하고, 연구동향을 분석하였다. 이를 통해 스마트도시에서 시민참여에 관한 연구방향을 이해하고, 향후 관련 연구에 대한 방향성을 제시하는 근거자료로 활용될 수 있을 것으로 기대된다.