• 한국시뮬레이션학회논문지
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• 제8권1호
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• pp.19-33
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• 1999

The fundamental issues to evaluate machine tools performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. This proposed algorithm could be used in the designed virtual machining system. The system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.

• Journal of Information Processing Systems
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• 제8권1호
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• pp.101-118
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• 2012

Embedded products are becoming richer in features. Simulation tools facilitate low-costs and the efficient development of embedded systems. SID is an open source simulation software that includes a library of components for modeling hardware and software components. SID components were originally written using C/C++ and Tcl/Tk. Tcl/Tk has mainly been used for GUI simulation in the SID system. However, Tcl/Tk components are hampered by low performance, and GUI development using Tcl/Tk also has poor flexibility. Therefore, it would be desirable to use a more advanced programming language, such as Java, to provide simulations of cutting-edge products with rich graphics. Here, we describe the development of the Java Bridge Module as a middleware that will enable the use of Java Components in SID. We also extended the low-level SID API to Java. In addition, we have added classes that contain default implementations of the API. These classes are intended to ensure the compatibility and simplicity of SID components in Java.

• International Journal of Quality Innovation
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• 제6권1호
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• pp.74-97
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• 2005

IDEF0 is the IEEE standard for functional enterprise modeling and has been used for business process modeling or process mapping in US and Europe. But it does not reflect the potential benefits of modeling and simulation of the dynamic aspects of an enterprise or a system. On the other hand, simulation tools concentrate mostly on the simulation of material flows and are difficult to include information flows and control flows. Additionally, the simulation models that include elements such as queues, event generators and process nodes is a visual interactive representation for the model builder, but is inconvenient for the domain expert. In an attempt to fill that void, we provide an integration of business process and simulation models in this paper. An enhancement of the IDEF0, called parameterized IDEF0, is proposed and its conversion mechanism to network simulation model is developed. Using this methodology, business process models for alternative systems can be evaluated and compared through simulation on time, cost, and quality metrics. As an application of the proposed methodology, economic evaluation of EDI (Electronic Data Interchange) for time-based BPR (Business Process Redesign) is demonstrated. In addition to BPR, the developed methodology may be further integrated with ABC (Activity Based Costing), TQM (Total Quality Management), and economic evaluation of information systems.

• 정보처리학회논문지C
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• 제18C권1호
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• pp.31-44
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• 2011

네트워크 기반의 적절한 컴퓨팅은 네트워크 대역폭의 가용성에 의존한다. 백본 네트워크 용량과 액세스 네트워크 상에 심각한 버틀넥이 발생하여 ISP 사업자와 고객 간의 갭이 발생된다면 그만큼 ISP 사업자는 사업에 불이익을 초래할 수 있다. 이러한 상황이 발생되기 이전 ISP 사업자가 트래픽량 예측과 종단간 오버로드가 높은 링크 구간을 감지할 수 있다면 ISP 사업자와 고객 간의 갭은 그만큼 줄어 들 수 있을 것으로 판단된다. 따라서 본 논문은 트래픽량 예측과 종단간 오버로드가 높은 링크 구간을 감지 가능한 소프트웨어로 ACE, ADM, Flow Analysis를 소개한다. 이들 툴을 이용하여 전자상거래의 연속적인 트랜잭션을 실망에서 측정한 후 측정된 네트워크 데이터를 가상 망 환경에 임포트하고 백그라운드 트래픽을 생성한다. 이와 같은 가상 망 환경을 토대로 점차적인 사용자 수 증가에 따른 트래픽량 예측과 링크 로드가 높은 구간을 시뮬레이션 결과로 알 수 있었다.

• Advances in aircraft and spacecraft science
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• 제2권2호
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• pp.169-182
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• 2015

Aeronautics engine cooling is one of the biggest problems that engineers have tried to solve since the beginning of human flight. Systems like radiators should solve this purpose and they have been studied extensively and various solutions have been found to aid the heat dissipation in the engine zone. Special interest has been given to air coolers in order to guide the air flow on engine and lower the high temperatures achieved by the engine in flow conditions. The aircraft companies need faster and faster tools to design their solutions so the development of tools that allow to quickly assess the effectiveness of an cooling system is appreciated. This paper tries to develop a methodology capable of providing such support to companies by means of some application examples. In this work the development of a new methodology for the analysis and the design of oil cooling systems for aerospace applications is presented. The aim is to speed up the simulation of the oil cooling devices in different operative conditions in order to establish the effectiveness and the critical aspects of these devices. Steady turbulent flow simulations are carried out considering the air as ideal-gas with a constant-averaged specific heat. The heat exchanger is simulated using porous media models. The numerical model is first tested on Piaggio P180 considering the pressure losses and temperature increases within the heat exchanger in the several operative data available for this device. In particular, thermal power transferred to cooling air is assumed equal to that nominal of real heat exchanger and the pressure losses are reproduced setting the viscous and internal resistance coefficients of the porous media numerical model. To account for turbulence, the k-${\omega}$ SST model is considered with Low- Re correction enabled. Some applications are then shown for this methodology while final results are shown in terms of pressure, temperature contours and streamlines.

• 대한의용생체공학회:의공학회지
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• 제30권6호
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• pp.482-488
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• 2009

Conventional devices for transanal endoscopic microsurgery that are currently used clinically for intestine or rectal cancer patients have 40 mm external diameter of rectoscope tube - induces anal damage and long-term postoperative pain for small-sized patients. In this paper, we designed rectum and rectoscope models and calculated the changing trends of operation area of the surgical tools in accordance with the step-by-step variation of design parameters of the rectoscope tube - external diameter, axial length, and distal angle. Using the results of computer simulation, we suggested an optimal set of design parameters that minimizes external diameter of the rectoscope tube and at the same time, maintains similar operation area of the surgical tools compared with commercialized devices (${\geq}\;4274.7mm^2$). The results of the simulation showed that the optimal design parameters were 35 mm external diameter, 100 mm axial length, and $45^{\circ}$ distal angle of the rectoscope tube. This result can be applied to the development of endoscopic microsurgery device that can minimize side effects to the intestine or rectal cancer patients.

• 대한공간정보학회지
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• 제16권2호
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• pp.57-65
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• 2008

레이저레이더 시뮬레이션의 성능을 향상시키기 위해서는 시뮬레이터의 레이저신호로 대응되는 공간의 범위와 해당 사물의 위치 및 속성정보를 정확하고 빠르게 획득해야 한다. 또한 시뮬레이션에 사용되는 데이터는 지형, 건물 및 차량과 같은 복잡한 3차원 객체들이며 광범위한 지역을 대상으로 하므로 가시화를 위한 일반적인 3차원 모델링 툴로는 빠르게 데이터를 추출하고 연산을 수행하기 어렵다. 본 연구에서는 이와 같은 복합적인 형태의 3차원 객체를 데이터베이스에 저장하고 필요한 질의를 수행하며, 가시화 부분과 연동할 수 있는 기법을 제시하였다. 이를 위해 3차원 다면체를 토폴로지 기반으로 데이터모델링을 수행하는 과정과 이러한 객체를 공간 DBMS를 이용하여 구현하는 과정을 예시하였다. 또한 DB에 저장된 데이터를 접근하여 가시화하는 과정을 VRML을 이용하여 구현하고, 시뮬레이션 레이저신호와의 연산 테스트를 실시하였다. 향후 데이터모델에 대한 연구와 가시화 부분에서의 LOD적용 등의 문제를 해결한다면 시뮬레이션뿐 아니라 보다 다양한 상황에 적용할 수 있을 것이다.

• 반도체디스플레이기술학회지
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• 제18권1호
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• pp.10-14
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• 2019

In this study, we synthesized two $Y_3Al_5O_{12}:Ce^{3+}$ phosphors ($7{\mu}m$-sized and $2{\mu}m$-sized YAG) with different sizes by controlling particles sizes of starting materials of the phosphors for white LED. In the smaller one ($2{\mu}m$-sized YAG), its photoluminescence intensity in the reflective mode was 63 % that of the bigger one ($7{\mu}m$-sized YAG); the quantum efficiencies were 93 % and 70 % for the smaller and the bigger ones. Two kinds of white LED packages with the same color coordinates were fabricated with a blue package (chip size $53{\times}30$) and two phosphors. The luminous flux of the white LED package with the smaller YAG phosphor was 92 % of that with the bigger one, indicating that the quantum efficiency of phosphor dispersed inside LED package was higher than that of the pure powder. It was consistently confirmed by the optical simulation (LightTools 6.3). It is notable according to the optical simulation that the white LED with the smaller phosphor showed 24 % higher luminous efficiency. If the smaller one had the same quantum efficiency as the bigger one (~93 %). Therefore, it can be suggested that the higher luminous efficiency of white LED can be possible by reducing the particle size of the phosphor along with maintaining its similar quantum efficiency.

• 한국멀티미디어학회논문지
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• 제18권5호
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• pp.641-651
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• 2015

This study intends to develop an evacuation simulation system based on BIM in a real-time manner. The proposed system, an add-on module for Revit Architecture and one of the most popular BIM authoring tools, supports the architectural design as well as real-time evacuation simulation of the design alternatives. This paper introduces the developed system, named SafeBIM, and the design process on which it is based. To evaluate the possibilities of the proposed system in the educational field of architectural design, this study included a feasibility test with college students in an architectural design studio.

• 한국CDE학회논문집
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• 제15권4호
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• pp.271-278
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• 2010

Weapon systems for future war require operating various war scenarios that are getting complex. Similarly, modeling and simulation technique is getting attention to acquire more effective weapon systems. Several S/W tools exist for simulating small scale engagements which depict a kind of war. However, it is very hard to model combat objects more systematic, and reuse them. To overcome these difficulties, this paper presents a modeling methodology for simulating small scale engagement using the DEVS-formalism. In this paper, we systematically classified and defined combat objects, likewise, explain a framework for a small scale combat simulation.