• Journal of applied mathematics & informatics
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• 제42권2호
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• pp.291-303
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• 2024

In this paper, we consider a feedforward network of overloaded multiclass processor sharing queues and we give a fluid model solution under the condition that the system is initially empty. The main theorem of the paper provides sufficient conditions for a fluid model solution to be linear with time. The results are illustrated through examples.

• 한국전자통신학회논문지
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• 제15권1호
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• pp.167-172
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• 2020

큰 규모의 소프트웨어 개발에서 모델링의 중요성은 이미 확인된 사항이다. 그리고 대부분의 프로젝트에서 모델링은 UML을 활용하여 수행되고 있다. 하지만 UML은 클래스를 중심으로 설계된 모델링 도구로서 공통모듈이나 컴포넌트, 프로세스 그리고 데이터의 모델링을 수행하기에는 복잡하고 기능이 부족하다. 이런 점을 보완하고자 컴퓨터 분야에서 개발되었던 구조적 방법론, 정보공학 방법론을 포함한 다양한 모델링 기법을 통합해서 사용하는 방안을 제시함으로써 실제 산업 현장에 도움이 되고자 한다. 이번 논문을 통하여 고객이 만족하는 소프트웨어의 개발을 위해서는 UML만 사용하지 않고 다양한 방법론의 기법을 사용하는 것이 유용함을 보이고자 한다.

• KIEAE Journal
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• 제15권5호
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• pp.95-105
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• 2015

Purpose: This paper presents a framework development for BIM (Building Information Modeling)-based OOPM (Object-Oriented Physical Modeling) for Building Thermal Simulation. The framework facilitates decision-making in the design process by integrating two object-oriented modeling approaches (BIM and OOPM) and efficiently providing object-based thermal simulation results into the BIM environment. Method: The framework consists of a system interface between BIM and OOPM-based building energy modeling (BEM) and the visualization of simulation results for building designers. The interface enables a BIM models to be translated into OOPM-based BEM automatically and the thermal simulation from the created BEM model immediately. The visualization module enables the simulation results to be presented in BIM for building designers to comprehend the relationships between design decisions and the building performances. For the framework implementation, we utilized the Modelica Buildings Library developed by the Lawrence Berkeley National Laboratory as a thermal simulation solver. We also conducted an experiment to validate the framework simulation results and demonstrate our framework. Result: This paper demonstrates a new methodology to integrate BIM and OOPM-based BEM for building thermal simulation, which enables an automatic translation BIM into OOPM-based BEM with high efficiency and accuracy.

• Smart Structures and Systems
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• 제19권1호
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• pp.67-90
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• 2017

The interdisciplinary research area of small scale energy harvesting has attracted tremendous interests in the past decades, with a goal of ultimately realizing self-powered electronic systems. Among the various available ambient energy sources which can be converted into electricity, wind energy is a most promising and ubiquitous source in both outdoor and indoor environments. Significant research outcomes have been produced on small scale wind energy harvesting in the literature, mostly based on piezoelectric conversion. Especially, modeling methods of wind energy harvesting techniques plays a greatly important role in accurate performance evaluations as well as efficient parameter optimizations. The purpose of this paper is to present a guideline on the modeling methods of small-scale wind energy harvesters. The mechanisms and characteristics of different types of aeroelastic instabilities are presented first, including the vortex-induced vibration, galloping, flutter, wake galloping and turbulence-induced vibration. Next, the modeling methods are reviewed in detail, which are classified into three categories: the mathematical modeling method, the equivalent circuit modeling method, and the computational fluid dynamics (CFD) method. This paper aims to provide useful guidance to researchers from various disciplines when they want to develop and model a multi-way coupled wind piezoelectric energy harvester.

• 한국CDE학회논문집
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• 제9권1호
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• pp.19-26
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• 2004

It is not possible to exchange parametric information of CAD models based on the current version of STEP (Standard for the Exchange of Product model data). The designer intents are lost during the transfer of CAD models. To resolve this problem, the macro-parametric approach had been proposed. To enable this approach, a set of standard modeling commands has been defined. Errors or missing elements of the standard modeling commands can be discovered by implementing macro-parametric translators. But there is a limit to discover problems only by using translators. This paper proposes a method to verify the standard modeling commands by implementing a geometric modeler. First, each argument of a modeling command is verified. Second, the set of the standard modeling commands is applied to geometric modeling of commercially available product parts. For the geometric modeling, nine test models have been selected.

• 한국학교수학회논문집
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• 제21권4호
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• pp.327-342
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• 2018

본 연구의 목적은 관점, 영역, 수준으로 구성된 삼차원 수학적 모델링 맵을 활용하여 수학적 모델링에 관한 국내 연구를 되돌아보고, 향후 수학적 모델링 연구에 대한 시사점을 주는 데 있다. 그 결과, 수학적 모델링에 관한 국내 연구는 응용 관점, 개념과 교실 영역, 중등학교 수준에 집중되어 있었고, 앞으로 개념 형성 관점, 시스템 영역, 대학교 및 교사(교육) 수준에서의 다양한 연구가 요구됨을 알 수 있었다.

• Smart Structures and Systems
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• 제13권3호
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• pp.407-418
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• 2014

The purpose of this paper is to present an Integrated Life Cycle Bridge Information Modeling that can be used throughout different phases of the bridge life cycle including: design, construction, and operation and maintenance phases. Bridge Information Modeling (BrIM) has become an effective tool in bridge engineering and construction. It has been used in obtaining accurate shop drawings, cost estimation, and visualization. In this paper, BrIM is used as an integrated tool for bridges life cycle information modeling. In the design phase, BrIM model can be used in obtaining optimum construction methods and performing structural advanced analysis. During construction phase, the model selects the appropriate locations for mobile cranes, monitors the status of precast components, and controls documents. Whereas, it acts as a tool for bridge management system in operation and maintenance phase. The paper provides a detailed description for each use of BrIM model in design, construction, and operation and maintenance phases of bridges. It is proven that BrIM is an effective tool for bridge management systems throughout their life phases.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2003년도 춘계학술대회 논문집
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• pp.101-106
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• 2003

This paper introduces the basic concept of computational modeling of perception processes for multimedia data. Such processes are modeled as hierarchical inter-and relationships amongst information in physical, physiological, psychological and cognitive layers in perception. Based on our framework, this paper gives the , algorithms for content-based retrieval for multimedia database systems.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(3)
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• pp.43-46
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• 2000

In this paper, we propose the method to express various factors for software architecture modeling effectively using UML extension mechanism. Furthermore, we show usefulness of proposed method by presenting several modeling techniques and their examples.

• 경영과학
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• 제11권1호
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• pp.59-72
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• 1994

In this paper we examine potentials of a spreadsheet program, one of the most widly available software system, as a mathematical optimization modeling tool. For an illustrative example, a shortest path problem is modeled on Lotus-123 for practical use and an implementational framework and a general guide to the spreadsheet modeling of network analysis is provided.