• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.04a
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• pp.409-414
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• 1994

A FMS is a typical discrete event system exhibiting concurrency, asynchronicity and non-determinism. Torepresent a FMS with those chatcteristics, Colored and Timed Petri Nets is defined and the modeling procedure is provided in this paper. Toanalyze and evaluate the performance of a FMS, a simulation software is developed and applied to SNU FMS/CIM Center. This software enables to detect the bottleneck machine and decide the optimaldirection in case of the expansion of a FMS.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.174-181
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• 1994

A FMS is a typical discrete event system exhibiting concurrency, asynchronicity and non-determinism. To represent a FMS with those characteristics, Colored and Timed Petri Nets is defined and the modeling procedure is provided in this paper. To analyze and evaluate the performance of a FMS, a simulation software is developed and applied to SNU FMS/CM Center. This software enables to detect the bottleneck machine and decide the optimal direction in case of the expansion of a FMS.

• Journal of the Korea Society for Simulation
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• v.7 no.2
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• pp.45-62
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• 1998

This research is concerned with buffer management in a multi-cell FMS with an AGVS. Buffers in manufacturing systems are required to reduce blocking and starving caused by breakdowns, variability in process times, and diversity of part routing. Due to the high per unit buffer cost, which primarily consists of floor space and equipment costs, the total capacity of buffers in and FMS is very limited. Proper buffer management can provide a high system efficiency. This paper presents a buffer management model for a multi-cell FMS with an AGVS and a simulation study to compare the proposed model to a conventional buffer management model in a job shop FMS.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.294-299
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• 1987

The concept of FMS (Flexible Manufacturing System) has been widely used in discrete parts manufacturing environment. But, it is very difficult to analyze enotrol FMS due to its complex and dynamic behaviour. This paper describes a Simulation program for performance evaluation of FMS. The program is written in FORTRAN and is capable of simulating different configurations.

• Journal of the Korea Society for Simulation
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• v.11 no.4
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• pp.57-68
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• 2002

The analysis of the cyclic scheduling problem in FMS using the transitive matrix has been proposed. Since the transitive matrix may explain all the relations between the places and transitions, we propose an algorithm to get good solution after slicing off some subnets from the original net based on machines operations. For analyzing the schedule problem, we considered two time functions such as produce time and waiting time using the P-invariant. In addition, we are shown the effectiveness of proposed algorithm after comparing with unfolding algorithms.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.1
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• pp.1-10
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• 2003

A recent trend In flexible manufacturing systems (FMS) Is to utilize the Identical versatile machines with fast tool delivery devices. Unlike a conventional FMS where parts are fed to the machines with the required tools, tools are acquired from other machines using a tool delivery system and parts can be finished on the same machine In these FMS. Therefore it Is more important problem 4o plan tool flow using tool delivery system In these FMS rather than part flow In conventional FMS. According to the existing study, In FMS 20∼30 percent of the total management cost Is the cost related with tools and It Is possible to reduce the tool Inventory by 40 percent using efficient tool allocation. In this study, In FMS under dynamic tool allocation strategy, a new method of part release considering tool flow at the stage of part release Is proposed. In order to prove the efficiency of the proposed part release It is compared with other part release through simulation experiments. Performance measures in these experiments are the throughput and the number of tardy parts.

• Proceedings of the Korea Society for Simulation Conference
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• 1993.10a
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• pp.16-16
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• 1993

The efficient use of capital intensive FMS requires determination of effective dispatching priority with which the parts of the selected part types are to be inputed into the system. This paper presents a simulation-optimization approach to find an appropriate dispatching priority. The study is based on a detailed simulator for a module-type commercial FMS, Specifically, after presenting the basic configuration and fundamental control logic of the system together with its main characteristics as a special type of a job shop, an algorithm is presented which combines simulated annealing and simulation to explore a dispatching priority of operations that minimizes the total tardiness, Computational performance of the algorithm shows that good solutions can be obtained within a reasonable amount of computations. The paper also compares the performance of the "optimal" or near optimal dispatching priority generated by the proposed algorithm with those generated by standard dispatching rules such as SPT, EDD and SLACK.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.2
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• pp.53-58
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• 2021

In this paper, an alternative finite memory structure(FMS) smoothing filter is developed for discrete-time state-space model with a control input. To obtain the FMS smoothing filter, unbiasedness will be required beforehand in addition to a performance criteria of minimum variance. The FMS smoothing filter is obtained by directly solving an optimization problem with the unbiasedness constraint using only finite measurements and inputs on the most recent window. The proposed FMS smoothing filter is shown to have intrinsic good properties such as deadbeat and time-invariance. In addition, the proposed FMS smoothing filter is shown to be equivalent to existing FMS filters according to the delay length between the measurement and the availability of its estimate. Finally, to verify intrinsic robustness of the proposed FMS smoothing filter, computer simulations are performed for a temporary model uncertainty. Simulation results show that the proposed FMS smoothing filter can be better than the standard FMS filter and Kalman filter.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.1
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• pp.19-30
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• 1996

We formulate the problem and propose a new heuristic method for determining the number of pallets of each type of component parts produced in FMS. The proposed method uses the Schweitzer's mean value analysis algorithm of which robustness and fitness for this problem is shown through simulation experiments. This method finds a better solution more efficiently than Solot's PANORAMA, which is well-known method to determine the number of pallets of FMS.

• IE interfaces
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• v.4 no.1
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• pp.83-91
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• 1991

This study proposes a half-simulation-half-real system that is used as an FMS building tool. In this hybrid system. softwares related to the operation of the FMS and the computer network on which the softwares run are real, while the physical movements of the devices in the system are simulated. The study shows the structure of the proposed system as well as the building procedure for the system. Adventages and usages of the system are also stated in detail.