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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Society for Simulation
Journal Basic Information
Journal DOI :
The Korea Society for Simulation
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Volume & Issues
Volume 10, Issue 4 - Dec 2001
Volume 10, Issue 3 - Sep 2001
Volume 10, Issue 2 - Jun 2001
Volume 10, Issue 1 - Mar 2001
Selecting the target year
APPLICATION OF DISCRETE EVENT SIMULATION TO PRODUCTION SCHEDULING
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 1~12
This article describes the application of discrete event simulation in a process industry (coffee manufacturing) as a daily production-scheduling tool. A large number of end products (around 300), sporadic demand, and limited shelf life of coffee (90 days) make it difficult to generate feasible production schedules manually. To solve this problem, an integrated system was developed incorporating discrete event simulation methodology into scheduling process. The integrated system is comprised of two components: a scheduling program and a simulation model. The scheduling program is used to generate daily schedules for roasting, grinding, and packing coffee. The simulation model uses the generated schedules to simulate the production of coffee and regenerates a modified production schedule. In this paper, each of the components will be described in detail, evaluated in terms of performance factors, and validated with a set of real production data. Although this article focuses on a specific system, we will share our experiences and Intuitions gained and encourage other process industries to develop simulation-based scheduling tools.
A study on the analysis method of Petri Net Models Using the Transitive Matrix
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 13~24
We propose a divide-conquer method of Petri nets under the condition of one-boundedness for all the Petri nets. We introduce the P-invariant transitive matrix of Petri nets and relationship between them. The feature of the P-invariant transitive matrix is that each element stands for the transitive relationship between input place and output place through the firing of the enable transition.
A Study on the Interface Circuit Creation Algorithm using the Flow Chart
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 25~34
In this paper, we describe the generation method of interface logic which replace between IP & IP handshaking signal with asynchronous logic circuit. Especially, we suggest the new asynchronous sequential "Waveform to VHDL" code creation algorithm by flow chart conversion : Wave2VHDL - if only mixed asynchronous timing waveform is presented the level type input and pulse type input for handshaking, we convert waveform to flowchart and then replace with VHDL code according to converted flowchart. Also, we confirmed that asynchronous electronic circuits are created by applying extracted VHDL source code from suggest algorithm to conventional domestic/abroad CAD Tool, Finally, we assured the simulation result and the suggest timing diagram are identical.
A Simulation Study for Inventory Policies in a Multi-Echelon Supply Chain
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 35~50
Managing multi-echelon inventory systems has gained importance over the last decade mainly because integrated control of supply chains consisting of several processing and distribution stages has become feasible through modern information technology. Determination of optimal inventory policy for multi-echelon supply chain is made difficult by the complex interaction between the different levels. In this paper, we investigate performance of five inventory policies (fixed quantity order policy, fixed interval order policy, compromised order policy, lead time-fixed quantity order policy, and mixed order policy) in a multi-echelon supply chain by using a simulation model constructed with AweSim simulation language. The results of the simulation study show that the mixed order policy is the best among five inventory policies in the most test problems except the case when the stockout cost per unit is much higher than the inventory holding and transportation costs per unit.
A Simulation Study for Comparison and Evaluation of Alternative Plans for the Productivity Improvement
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 51~62
For the productivity improvement, it is necessary to analyze problem of the system and evaluate alternative plans. But, it if hard to experiment and evaluate alternative plans in real existing system. Therefore, it is necessary to synthetically analyze and evaluate alternative plans using simulation and statistical analysis method. In this case study, as a simulation language, Promodel is used to compare and evaluate four alternatives which are considered to improve the productivity of an object system. The object system is constituted of a pretreatment line and a painting line. The purpose of this study is to analyze whether the decrease of the down time in pretreatment line can be effective to the productivity improve comparing with exiting system and other alternatives. The other purpose is to choose an alternative that has the best productivity improvement. The results of the simulation show that the possibility of improvement in productivity by decreasing the down time of pretreatment line. Two-Stage Bonferroni Procedure is used to choose the best alternative.
A Simulation for the Natural Frequencies of Curved Pipes Containing Fluid Flow with Various Elbow Angles
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 63~65
To investigate the natural frequencies of curved piping systems with various elbow angles conveying flow fluid, a simulation is performed considering Initial tension due to the inside fluid. The system is analyzed by finite element method utilizing straight beam element. Elbow part is meshed using 4 elements, and the initial tension is considered by inserting equivalent terms into the stiffness matrix. Without considering the initial tension, the system becomes unstable, that is, the fundamental natural frequency approaches to zero value fast, as the flow velocity reaches critical value. With the initial tension terms, the system becomes stable where there is no abrupt decrease of the fundamental natural frequency. The change rate of the natural frequency with respect to the flow velocity reduces. As elbow angle increases, the system becomes stiffer, then around 150 degrees of the elbow angle the natural frequency has the largest value, the value decreases after the angle of the largest natural frequency. When angle is between 170 degrees and 179 degrees, the natural frequency is very sensitive. This means that small change of angle results in great change of natural frequency, which is expected to be utilized in the control of the natural frequency of the piping system conveying flow fluid.
Analysis For (N+1) Type M System Upgrade Plan
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 73~82
The main idea behind the Intelligent Networks (IN) concept is the separation of switching functionality from the service control, in order to meet various service requirements of subscribers and development of new services in time. On the increase of subscriber and for high quality of service, the IN upgrades its service systems, and there are a number of ways depending on the system architecture and the characteristics of services. This paper compares two alternatives, traces the performance of them by means of the simulation technique, and finally puts a rule to select one of them.
Security Simulation with Collaboration of Intrusion Detection System and Firewall
Journal of the Korea Society for Simulation, volume 10, issue 1, 2001, Pages 83~92
For the prevention of the network intrusion from damaging the system, both IDS (Intrusion Detection System) and Firewall are frequently applied. The collaboration of IDS and Firewall efficiently protects the network because of making up for the weak points in the each demerit. A model has been constructed based on the DEVS (Discrete Event system Specification) formalism for the simulation of the system that consists of IDS and Firewall. With this model we can simulation whether the intrusion detection, which is a core function of IDS, is effectively done under various different conditions. As intrusions become more sophisticated, it is beyond the scope of any one IDS to deal with them. Thus we placed multiple IDS agents in the network where the information helpful for detecting the intrusions is shared among these agents to cope effectively with attackers. If an agent detects intrusions, it transfers attacker's information to a Firewall. Using this mechanism attacker's packets detected by IDS can be prevented from damaging the network.