• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.61-69
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• 2008

In order to evaluate the performance of priority queues for future event list in discrete-event simulations, models representing patterns of enqueue and dequeue processes are required. The time complexities of diverse priority queue implementations can be compared using the performance models. This study aims at developing such performance models especially under the environment that a developed simulation model is used repeatedly for a long period. The developed performance model is based on multi-stage Markov process models; probabilistic patterns of enqueue and dequeue are considered by incorporating non-homogeneous transition probability. All necessary parameters in this performance model would be estimated by analyzing a results obtained by executing the simulation model. A case study with a war game simulation model shows how the parameters defined in muti-stage Markov process models are estimated.

• International Journal of Automotive Technology
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• v.6 no.1
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• pp.29-35
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• 2005

The structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, Noise/Vibration/Harshness (NVH), crashworthiness, and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, the Virtual Proving Ground (VPG) approach has been developed to simulate dynamic nonlinear events as applied to automotive ride & handling. The finite element analysis technique provides a unique method to create and analyze vehicle system models, capable of including vehicle suspensions, powertrains, and body structures in a single simulation. Through the development of this methodology, event-based simulations of vehicle performance over a given three-dimensional road surface can be performed. To verify the predicted dynamic results, a single lane change test was performed. The predicted results were compared with the experimental test results, and the feasibility of the integrated CAE analysis methodology was verified.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.483-491
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• 2007

This paper proposes a Situation Simulation Framework for implementing computer game and describes the possibility of analyzing game with unfolding situation. In last few years game systems have been evolving from the performance of physical engine, network traffic in the on line game to the representation of rendering physical phenomena. In computer game, a situation hierarchy structure which allows the designer for simulating high-level specifications of game structure. Logically simulated environment is created by defining situations and events based on hierarchy structure of the situation. We classify events into explicit event is occurred by user and implicit event is occurred by system. Our study defines the existence of objects is the most prevalent factor applied to any event in game world. The advantages of this approach are able to allow for providing the conceptual design for simulation game and analyzing the situation in the game world. And this method allows us to decrease the complexity of system design and abstraction modeling for the simulation game. Specially, the introduction of the definition of events allows us to approach game design in a structural manner rather than by their classification. The proposed method was implemented in the "Shooting BaDuk" among games.

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.23-36
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• 2018

Discrete Event System Specification (DEVS) has been used for decades as it provides sound semantics for hierarchical modular specification of discrete event systems. Instead of the mathematical specification, the DEVS diagram, based on the structured DEVS formalism, has provided more intuitive and convenient representation of complex DEVS models. This paper proposes a clean room process for implementation and verification of a DEVS diagram model specification into a simulation software source code. Specifically, it underlies a sequence of transformation steps from conformance and integrity checking of a given diagram model, translation into a corresponding tabular model, and finally conversion to a simulation source code, with each step being inversely verifiable for traceability. A simple example helps developers to understand the proposed process with associated transformation methods; a case study shows that the proposed process is effective for and adaptable to practical simulation software development.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.400-408
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• 2009

Simulation applications for analyzing the productivity of construction operations at operation level and project schedules at project level are crucial methods in project management. The application at two different levels should be very tightly linked to each other in practice. However, appropriate integration at the levels is not achieved in that existing systems do not support to integrate operation models into a schedule model. This paper presents a new approach named to Discrete Event Simulation-Nesting modeling approach, which supports not only productivity analysis at operation level but also schedule management at a project level. The system developed by the authors allows creating operation models at the operation level, maintaining them in operation model library, executing sensitivity analysis to find the behaviors of the operation models when different combination of resources are used as existing DES systems do. On top of the conventional functions, the new system facilitates to find the optimum solution of resource combinations which satisfy the user's interest by computing the hourly productivity and the hourly cost of the operation. By drag-and-dropping an operation model kept in the operation model library, the operation models are integrated into an activity of the schedule model. When a complete schedule model is established by nesting operation models into the schedule model, stochastic simulation based scheduling is executed. A case study is presented to demonstrate the new simulation system and verify the validity of the system.

• Proceedings of the Safety Management and Science Conference
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• 2000.05a
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• pp.339-349
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• 2000

Inchon Port is the second largest import-export port of Korea, and has the point at issue such as the excessive logistics cost because of the limits of handling capacity and the chronic demurrage. There are few research activities on the analysis and improvement of the whole port operation, because Inchon Port not only has the dual dock system and various facilities but also handles a various kind of cargo. The purpose of this paper is to develop the simulation program as a long-term strategic support tool, considering the dual dock system and the TU(Terminal Operation Company) system executed since March, 1997 in Inchon Port. The basic input parameters such as arrival intervals, cargo tons, service rates are analyzed and the probability density functions for these parameters are estimated. The main mechanism of simulation model is the discrete event-driven simulation and the next-event time advancing. The program is executed based on the knowledge base and database. From the simulation model, it is possible to estimate the demurrage status through analyzing various scenarios and to establish the long-term port strategic plan.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.3
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• pp.209-219
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• 1996

Fieldbus provides a real-time data communication among field devices in the process control and manufacturing automation systems. In this paper, a Petri Net model of the 1993 draft of IEC/ISA fieldbus which is proposed as an international standard of fieldbus network is developed. Based on the Petri Net model, discrete-event simulation model of IEC/ISA fieldbus network is developed. This paper evaluates the network induced delay in the data link layer of IEC/ISA fieldbus using the simulation model. In addition, an integrated discrete-event/continuous-time simulation model of fieldbus system and distributed control system is developed. This paper investigates the real-time data processing capability of IEC/ISA fieldbus and the effect of network-induced delay to the performance of control system.

• Journal of IKEEE
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• v.24 no.2
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• pp.426-434
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• 2020

FMI is being researched as a standard for linking large-scale simulation of CPS. In order to guarantee the reliability of the results in large-scale simulations using FMI, event handling through time management techniques is required. This paper aims to guarantee real-time performance and accuracy in large-scale co-simulation environments such as CPS. Synchronize the wallclock time and simulation time to ensure real time. Also, to ensure the accuracy, before the simulation, the event is checked and the simulation is performed with the smallest step size while maintaining the real time until the event occurrence time. As a result, the events occurring in the co-simulation environment are processed immediately and sequentially, ensuring the real-time performance and minimizing the numerical integration error by maximizing the simulation resolution. In the experiment, the proposed method was processed immediately, and it was confirmed that the numerical integration error is reduced by about 1/5 unlike the existing time management method which does not guarantee the resolution.

• Journal of the Korea Society for Simulation
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• v.3 no.2
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• pp.1-13
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• 1994

Deep reasoning procedures are model-based, inferring single or multiple causes and/or timing relations from the knowledge of behavior of component models and their causal structure. The overall goal of this paper is to develop an automated deep reasoning methodology that exploits deep knowledge of structure and behavior of a system. We have proceeded by building a software environment that uses such knowledge to reason from advanced symbolic simulation techniques introduced by Chi and Zeigler. Such reasoning system has been implemented and tested on several examples in the domain of performance evaluation, and event-based control.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.9-10
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• 2001

Simulation has been evolved with the advance of computer and technique of modeling application systems. Early simulations were numerical analysis of engineering models known as continuous simulation, analysis of random events using various random number generators thus named as Monte Carlo simulation, iud analysis o(\\\\`queues which are prevalent in many real world systems including manufacturing, transportation, telecommunication. Discrete-event simulation has been used far modeling and analyzing the systems with waiting lines and inefficient delays. These simulations, either discrete-event, continuous, or hybrid, have played a key role in industrial age by helping to design and implement the efficient real world systems. In the information age which has been brought up by the advent of Internet, e-business has emerged. E-business, any business using Internet, can be characterized by the network of extended enterprises---extended supply and demand chains. The extension of value chains spans far reaching scope in business functions and space globally. It also extends to the individual customer, customer preferences and behaviors, to find the best service and product fit for each individual---mass customization. Simulation should also play a key role in analyzing and evaluating the various phenomena of e-business where the phenomena can be characterized by dynamics, uncertainty, and complexity. In this tutorial, applications of simulation to e-business phenomena will be explained and illustrated. Examples are the dynamics of new economy, analysis of e-business processes, virtual manufacturing system, digital divide phenomena, etc. Partly influenced by e-business, a new trend of simulation has emerged called agent-based simulation, Agent-based simulation is a technique of simulation using software agent that have autonomy and proactivity which are useful in analyzing and integrating numerous individual customer's behavior. One particular form of agent-based simulation is swarm. This tutorial concludes with the illustration of swarm or swarm Intelligence applied to various e-business applications, and future directions and implications of this new trend of simulation.