• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.441-442
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• 2010

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.841-843
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• 1989

Aspects of modelling, performance monitoring, control and optimisation are discussed, with particular reference to the application of SPEEDUP. A new facility is described which allows SPEEDUP to operate in conjunction with other systems and several examples are briefly given of its power and flexibility. In particular, its use in on-line applications alongside plant management and distributed control systems is described and how it can be used in scheduling/sequencing problems in investigating batch and cyclic problems.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.461-462
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.727-728
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• 2011

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.73-80
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• 2007

This article aims to optimize the nitrogen removal of a sequencing batch reactor (SBR) through the use of the activated sludge model and iterative dynamic programming (IDP). Using a minimum batch time and a maximum nitrogen removal for minimum energy consumption, a performance index is developed on the basis of minimum area criteria for SBR optimization. Choosing area as the performance index makes the optimization problem simpler and a proper weighting in the performance index makes it possible to solve minimum time and energy problem of SBR simultaneously. The optimized results show that the optimal set-point of dissolved oxygen affects both the total batch time and total energy cost. For two different influent loadings, IDP-based SBR optimizations suggest each supervisory control of batch scheduling and set-point trajectory of dissolved oxygen (DO) concentration, and can save 20% of the total energy cost, while meeting the treatment requirements of COD and nitrogen. Moreover, it shows that the re-optimization of IDP within a batch can solve the modelling error problem due to the influent loading changes, or the process faults.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1303-1310
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• 1999

In this paper, the Timed Petri-Nets(TPN) modeling of Modular Cell Manufacturing Systems(MCMS) was investigated to overcome the limit of batch mode operation, which has been one of the most popular manufacturing types to produce an extensive industrial output and to be able to adopt to suitable and quickly changing manufacturing environments. A model of the MCMS was developed in reference to the actual TFT-LCD manufacturing system. TFT-LCD manufacturing system is not mass-productive in batch mode, but it operates in the form of MCMS which consists of a sequence of several cells with four processes of operation, including those of color filter(C/F), TFT, cell, and module. The cell process is further regrouped in those of Front-End and Back-End. For the Back-End cell process, it is reconstructed into a virtual model, consisting of three cells. The TPN modeling encompasses those properties, such as states and operations of machines, the number of buffers, and the processing time. The performance of the modeling was further examined in terms of scheduling system. The productivity in each cells was examined with respect to the change of failure rate of the cell machines and Automatic Guided Vehicles(AGV) using simulation by TPN.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.30-35
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• 1993

Simple recurrence relations for calculating completion times of various storage polices (unlimited, intermediate storages(FIS), finite intermediate storages(FIS), no intermediate storage(NIS), zero wait(ZW) for serial multi-product multi-unit processes are suggested. Not only processing times but also transfer times, set-up (clean-up) times of units and set-up times of storages are considered. Optimal scheduling strategies with zero transfer times and zero set-up times had been developed as a mixed integer linear programniing(MILP) formulation for several intermediate storage policies. In this paper those with non-zero transfer times, non-zero set-up times of units and set-up times of storages are newly proposed as a mixed integer nonlinear programming(MINLP) formulation for various storage polices (UIS, NIS, FIS, and ZW). Several examples are tested to evaluate the robustness of this strategy and reasonable computation times.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.2
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• pp.44-53
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• 2000

The waiting delays of users are inevitable in this policy since the services are not taken immediately upon requests but upon every scheduling points. An inefficient management of such delays makes an unfair service to users and increases the possibility of higher reneging rates. This paper proposes an adaptive batch scheduling scheme which improves the average waiting time of users requests and reduces the starvation problem of users requesting less popular movies. The proposed scheme selects dynamically multiple videos in given intervals based on the service patterns which reflect the popularity distribution(Zipf-distribution) and resource utilizations. Experimental results of simulations show that the proposed scheme improves about 20-30 percentage of average waiting time and reduces significantly the starving requesters comparing with those of conventional methods such as FCFS and MQL.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.9-16
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• 1995

The erection process planning is to decide erection strategy and sequence that satisfies dock duration. The erection scheduling is to decide erection date of each block. The load profile varies according to scheduling and it is related to building cost. It must be possible to simulate the various combinations of process plan and schedule for optimal planning. To develop the process planning system for optimal planning, the system that generate the sequence of erection automatically and the load leveling system are required. This paper suggests the method that generates the erection sequence. The load leveling should be done to all the ships in the same dock batch to get reliable results. In this case since the search space is very large, efficient optimization method is needed Our research achieved the load leveling system using Genetic Algorithm. This system made it possible to simulate various process plans to which schedule is considered.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.952-965
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• 1993

A simulation modeling is necessary for the optimal design of a rice processing plant, which consists of a facility (a silo system) of rice drying and storage and a rice mill plant. In a rice processing plant, the production scheduling and the decision on capcity of each unit based on a queuing theory is very important and difficult. In this study a process-oriented simulation model was developed for the design of a rice drying and storage system with SLAMSYSTEM. The simulation model is capable of simulating virtually all the processing activities and provides work schedules which minimize total processing time , mean flow time and bottleneck of the plant system and estimate drying time for a batch in a drying silo. Model results were used for determination the size and capacity of each processing unit and for analyzing the performance of the plant . The developed model was actually applied to construct a grain silo system for rice drying and storage.