The model of a FMS (Flexible Manufacturing System) admits to a natural hierarchical decomposition of highly decoupled units with similar structure and control. The FMS fractal architecture model represents a hierarchical structure built from elements of a single basic design. A SES (System Entity Structure) is a structural knowledge representation scheme that contains knowledge of decomposition, taxonomy, and coupling relationships of a system necessary to direct model synthesis. A substructure of a SES is extracted for use as the skeleton for a model. This substructure is called pruned SES and the extraction operation of a pruned SES from a SES is called pruning (or pruning operation). This paper presents a pruning operation called recursive pruning. It is applied to SES for generating a model structure whose sub-structure contains copies if itself as in FMS fractal architecture. Another pruning operation called delay pruning is also presented. Combined with recursive pruning the delay pruningis a useful tool for representing and constructing complex systems.

In general, simulation and analytic method are used for real system analysis. However, or date, there has been only the theoretical works on each approach. Therefore it is required that we study on the relationship between each approaches to obtain more reliable and correct system analysis results. In this paper, using SPN(Stochasitc Petri Net) formalism, we propose the method of output prediction of the DEVS(Discrete Event system Specification) simulation. For this we suggest a transformation algorithm which transform SPN form DEVS formalism based on the event scheduling world view and a verification algorithm for it. We then show an example to apply it to the real system, such that the Grocery Store System.

We develop a variance reduction technique in one simulation experiment whose purpose is to estimate the parameters of a first-order linear model. This method utilizes the control variates obtained during the course of simulation run under Schruben and Margolin's method (S-M method). The performance of this method is shown to be similar in estimating the main effects, and to be superior to S-M method in estimating the overall mean response in the hospital simulation experiment. For the general case, we consider that a proposed method may yield a better result than S-M method if selected control variates are highly correlated with the response at each design point.

본 논문은 가상현실 어플리케이션을 제작하기 위한 가상세계 저작도구인 VRAT(Virtual Reality Authoring Tool)의 설계 및 구현에 대해 기술한다. VRAT는 3D desktop, immersive, reflexive metaphor를 지원하며 실시간 3D 센서 시스템과 폴리곤 렌더링 시스템을 기반으로 객체 지향적인 가상현실 운영시스템, 가상세계 데이터베이스, GUI를 통한 저작시스템으로 구성된다. 이들 하부 시스템은 완전히 결합되어 있어서 VRAT시스템을 사용한 응용프로그램의 수행중에 기존의 3D CAD 시스템등에서 제작한 모델을 가상세계내에 배치하고 이들에 행위양식을 부여하는 태스크를 지정하거나 입력장치인 센서를 모델이나 시점에 연결하여 조종하는 것이 가능하다. 제안된 시스템은 범용성과 이식성을 고려하여 UNIX와 X-Window 시스템을 기반으로 X11, GL, PIXRECT, VGA 그래픽 하부 시스템과 SGI, SUN, HP 등의 워크스테이션과 PC 상에서 구현되었다.

본 연구는 불확실한 경영환경하에서 전략목표에 영향을 미치는 환경요인을 확인하고, 이를 다시 전략계획 시뮬레이션 모형에 체계적으로 반영하기 위한 새로운 전략계획 시뮬레이션 모형을 제안한다. 본 연구에서 제안하는 전략계획 시뮬레이션 모형은 (1) 환경요인 분석을 위하여 퍼지인식도(Fuzzy Cognitive Map)를 적용하고, (2) 경쟁관계를 체계적으로 반영하기 위하여 미분게임(Differential Game) 모형을 이용한다. 퍼지인식도는 특정 의사결정 문제에 있어서 관련된 여러 개념간의 인과관계를 해석하고 그를 통하여 해당 문제전체에 관한 효과적인 의사결정을 지원하는 소위 구조적 모형화(Structural Modeling)도구의 한 방법이다. 한편, 본 연구에서는 미분게임을 이용하여, 퍼지인식도에 의하여 확인된 환경요인을 변수로 감안하고, 아울러 경쟁관계를 수식화 하므로써 보다 체계적인 시뮬레이션이 가능하다. 제안된 전략계획 수립 시뮬레이션 모형을 동태적 광고모형(dynamic advertising model)에 적용하므로써 보다 효과적인 경영전략계획 수립이 가능함을 보였다.

Local area networks(LANs) recently become so large that they exceed their architected limits and users on different LANs may need to talk each other. This trend has led to a growth in the practice of interconnecting many heterogeneous LANs. In this paper, we proposed a method to interconnect Ethernets and token rings, which are widely used today, through a fast FDDI network. We also developed a simulation tool to evaluate the performances of the interconnected networks. We used a simulation language SLAM II for modeling and OSF/MOTIF X-window for user interface. The developed tool can be used to make a decision which interconnecting method is suitable for a given environment before interconnecting many heterogeneous LANs.

There has been a great deal of interest in the area of group technology recently. They suggest that group technology's formation of cells of machines which are dedicated to production of families of parts will bring many of the advantages of cellular layout of job shops. In this context, Yoon [2] designed and suggested 3 types of the layout structure for a small firm, by introducing the cellular layout into the traditional flow line of an existing factory. Also he found that P5C, i.e. process layout /5 cells layout, outperformed the rest types. However, he performed the experiments in the standpoint of the existing factory operation and did not consider other operating methods including changing the dispatching and sequencing rules. Therefore, in this paper, we compared the performance of 3 different layout by the simulation technique using the real data from the existing factory, considering a newly suggested dispatching and machine selection rule.

Simulation techniques are used to improve the productivity of a textile factory. A simulation model is developed for the analysis of investment for dyeing process equipment, such as dryers and bleachers. For modeling and analysis, AIM (Analyzer for Improving Manufacturing) is used. AIM is a manufacturing oriented simulation software developed by Pritsker Corp. AIM provides interactive model building and simulation, automatic animation, and powerful graphic outputs. thereby, drastically reducing modeling efforts and also enhancing communication capabilities.

본 연구는 새로운 객체 지향 모델링 방법으로 VOOM(Various Object-Oriented Modeling)을 제안한다. VOOM은 시스템의 요소 뿐만 아니라 시스템 요소들간의 관계 및 그들로 이루어진 구조를 서로 유형이 다른 프레임으로 정의하여 객체화시키고, 객체화된 시스템 요소 및 관계, 구조를 서로 연결하여 하나의 시스템을 구축하도록 한다. 따라서 전체 시스템의 측면에서 구성 요소의 역할과 전체적인 시스템의 행위 및 구조를 쉽게 파악할 수 있도록 한다. VOOM을 통한 모델링 작업은 체계화되고 검증이 용이해지며, 모델의 유연성 및 재사용성이 확장되어질 수 있다. VOOM에 의한 모델링 작업 지원 가능성이 컴퓨터 통신망을 대상으로 한 시뮤레이션 모델링 예를 통해 제사하였다.

In 3D computer graphics, fractal techniques have been applied to terrain models. Even though fractal models have become popular for recreating a wide variety of the shapes found in nature, a specific 3D terrain model such as Uleung Island could not be formulated by statistical fractals easily owing to the random effects. However, by locating the midpoints on the edges and the surface of a specific terrain such as Uleung Island, a similar shape of the terrain model can be simulated. This paper shows the way of simulating 3D Uleung Island terrain model by the statistical fractals wherein the subdivision algorithm is used.

This paper deals with modeling and simulation of an industrial benzene-toluene-xylene plant. Because the fractionation unit of benzene-toluene-xylene plant has a narrow range of boiling point and doesn't have any sidecut and side reboiler, we employed boiling point estimation method in the modeling and simulation of the plant. Soave-Redlich-Kwong equation was used in the computation of thermodynamical properties. We solved resulting nonlinear equations by using Newton-Raphson method which is known to show fast convergence. Results of simulation showed good agreement with actual plant operation data.