• Korean Journal of Computational Design and Engineering
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• v.14 no.3
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• pp.176-185
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• 2009

Modern manufacturing systems consist of highly automated manufacturing devices, and they are controlled by complicated PLC programs. To make sure the achievement of the control objectives of a manufacturing system, it is very important to monitor the dynamic system behaviors of the manufacturing system. In this paper, we propose a monitoring methodology of a PLC program based on the Software In the Loop Simulation(SILS), which makes use of the time gap information between PLC signals. The errors relevant with PLC signals can be found using the proposed methodology, comparing a normal PLC signal trajectory with a target PLC signal trajectory. The proposed methodology has been implemented and tested with simple examples.

• Journal of Computational Design and Engineering
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• v.1 no.3
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• pp.194-201
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• 2014

Optimization of design is an important step in obtaining tissue engineering scaffolds with appropriate shapes and inner micro-structures. Different shapes and sizes of scaffolds are modeled using UGS NX 6.0 software with variable pore sizes. The quality issue we are concerned is the scaffold porosity, which is mainly caused by the fabrication inaccuracies. Bone scaffolds are usually characterized using a scanning electron microscope, but this study presents a new automated inspection and classification technique. Due to many numbers and size variations for the pores, the manual inspection of the fabricated scaffolds tends to be error-prone and costly. Manual inspection also raises the chance of contamination. Thus, non-contact, precise inspection is preferred. In this study, the critical dimensions are automatically measured by the vision camera. The measured data are analyzed to classify the quality characteristics. The automated inspection and classification techniques developed in this study are expected to improve the quality of the fabricated scaffolds and reduce the overall cost of manufacturing.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.117-139
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• 1999

This paper is concerned about the hybrid tandem configuration as the design of the automated guided vehicle system(AGVs). The hybrid tandem configuration is that the manufacturing system is divided into several non-overlapping zones, workstations of each zone are linked by network configuration including loop. That is, the manufacturing system is divided into several non-overlapping small size networks, and at most two automated guided vehicles can be available in each network. The transit point is located at proper point between adjacent networks. The parts are transported to workstations in other network through the transit points. One of the objective functions in dividing into the hybrid tandem configuration is to minimize the maximum travel time of the divided networks, and other is to minimize the total travel distance of parts moved to workstations in other networks for the next processing. The model formulation is presented, and a numerical example is shown. Also, the performances of system for the hybrid tandem, tandem and network configuration are compared through the simulation. The results of this research will contribute to the development of material handling systems in the manufacturing system. Also, it will be applied in determining the transportation area of transportation vehicles and the number and size of the transportation fleet in the transportation problem of logistics management.

• Asia pacific journal of information systems
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• v.16 no.4
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• pp.1-25
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• 2006

This research approached the negotiation problem from the seller's perspective in the make-to-order manufacturing industry in order to solve the multi-attribute automated negotiation problem. To this end, more than 'two negotiation attributes are defined and a preferred value of each negotiation alternative is calculated based on the entropy value of each attribute. And then, the best option is selected according to the utility function of each negotiator, a penalty of negotiation delay, and conviction of possibility of negotiation success. The suggested automated negotiation methods in this study can be employed for the development of advanced automated negotiation systems.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.314-316
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• 1993

In this paper, a method to detect and diagnose faults in Automated Manufacturing Systems(AMS) is proposed. In AMS, it is necessary to monitor the process-status. The detection and diagnosis of faults are often difficult in monitoring level with given passive data. We propose the model-based monitoring system for faults detection and diagnosis using Petri Nets to model AMS efficiently and easily. Simulation results show the validity of proposed method with example of Reverse Mill Process in Automated Mill Lines.

• Journal of the Korea Society for Simulation
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• v.6 no.1
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• pp.41-52
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• 1997

It is essential to construct an efficient material flow system for the successful introduction of automated manufacturing systems. Automated Guided Vehicle System (AGVS) plays a significant role more and more in modern manufacturing environments, because of the flexibility and the precision they offer. However, as the size and the complexity of systems increase, the problems of dispatching, routing and scheduling of AGVs become complicated due to their independent and asynchronous demands. In this paper, we review relevant papers, and provide a new and more efficient method for dispatching AGV, named MEVTT (Minimum Empty Vehicle Travel Time) and demonstrate its performance and efficiency using simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.287-297
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• 1997

This research is concerned with operation control problem for an automated manufacturing system which consists of two machine centers and a single automatic guided vehicle. The objective is to develop and evaluate heuristic scheduling procedures that minimize maximum completion time to be included travel time of AGV. A new heuristic algorithm is proposed and a numerical example illustrates the proposed algorithm. The heuristic algorithm is implemented for various cases by SLAM II. The results show that the proposed algorithm provides better solutions than the previous algorithms.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.43-52
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• 1991

The short-term production planning of an automated manufacturing system is to determine the production rate of each part type or family of part types. The purpose of this paper is to develop an optimal algorithm for solving the short-term production planning problem while machine failures, repairs. and changes in demand requirements are anticipated. The problem is formulated by LP and it shows that the production surplus is approached or stays at the hedging point. In addition, the long-term average frequencies of set-us with relation to a multilevel hierarchical production planing scheme are considered An example to show the effectiveness of the algorithm is presented.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.2
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• pp.68-74
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• 2003

Modem automated manufacturing processes employ automated guided vehicles(AGVs) for material handling, which serve several machining centers(MCs) in a factory. Optimal scheduling of AGVs can significantly help to increase the efficiency of the manufacturing process by minimizing the idle time of MCs waiting for the raw materials. In this paper, we will analyse the requirements for an optimal schedule and then provide a mathematical framework for an efficient schedule of material delivery by an AGV. With this model, the optimal number of MCs to be utilized will also be determined. Finally, the material delivery schedule employing multiple journeys to the MCs by the AGV will be carried out. Through rigorous analysis and simulation experiments, we shall show that such a delivery strategy will optimize the overall performance.

• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.33-44
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• 1995

This paper presents an automated visual inspection system for the electronic parts manufacturing process. In this system, a statistical process control (SPC) method is integrated into the automated inspection method on a real time base. It shows how the collected data can be analyzed with the SPC to provide process information. Also presented are studies of subpixel image processing technology to improve the accuracy of parts measurements, and the cumulative-sum (CUSUM) control chart for fraction defectives. An application of the developed system to connector manufacturing process as a part of computer integrated manufacturing (CIM) is presented.