• Title/Summary/Keyword: Plant Scheduling

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A Study on the Strategic Competition Model of Pumped Storage Plant (양수발전기의 전략적 시장참여에 대한 해석 모형 연구)

  • Lee, Kwang-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.10
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    • pp.1738-1743
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    • 2007
  • This paper addresses the bidding strategies of a pumped-storage hydro plant in an electricity market. Competitive bidding of pumping and generating of a pumped-storage plant is formulated in a game theoretic problem in accordance with the three different ownership of scheduling; Market Operator(MO), generating company(Genco), and combined type of MO and Genco. Optimal conditions for Nash Equilibrium are derived in the form of market prices during the scheduling periods. Simulation results show the different ownership models produce different schedules of pumping and generating, which correspond to the objective of the scheduling owner of a pumped-storage hydro plant.

Integrated scheduling model for PVC process

  • Kang, Min-Gu;Moon, Sung-Deuk;Kang, Jin-su;Park, Sun-Won
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1804-1809
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    • 2003
  • In a large-scale chemical plant, there are scheduling problems in inventory and packing process although production process is stabilized. The profit of the plant is restricted by these problems. In order to improve these problems, integrated scheduling model, which is concerned with whole processes from production to shipment, has been developed in this paper. In this model, decision variables are production sequence, silo allocation, amounts of bulk shipment and packing amounts. In case of a real plant, it is hard to solve by deterministic methods because there are too many decision variables to solve. In this paper, genetic algorithm is presented to solve a PVC process scheduling model within an hour with PCs.

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Design of a Coordinating Mechanism for Multi-Level Scheduling Systems in Supply Chain

  • Lee, Jung-Seung;Kim, Soo
    • Journal of Information Technology Applications and Management
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    • v.19 no.1
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    • pp.37-46
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    • 2012
  • The scheduling problem of large products like ships, airplanes, space shuttles, assembled constructions, and automobiles is very complex in nature. To reduce inherent computational complexity, we often design scheduling systems that the original problem is decomposed into small sub-problems, which are scheduled independently and integrated into the original one. Moreover, the steep growth of communication technology and logistics makes it possible to produce a lot of multi-nation corporation by which products are produced across more than one plant. Therefore vertical and lateral coordination among decomposed scheduling systems is necessary. In this research, we suggest an agent-based coordinating mechanism for multi-level scheduling systems in supply chain. For design of a general coordination mechanism, at first, we propose a grammar to define individual scheduling agents which are responsible to their own plants, and a meta-level coordination agent which is engaged to supervise individual scheduling agents. Second, we suggest scheduling agent communication protocols for each scheduling agent topology which is classified according to the system architecture, existence of coordinator, and direction of coordination. We also suggest a scheduling agent communication language which consists of three layers : Agent Communication Layer, Scheduling Coordination Layer, Industry-specific Layer. Finally, in order to improve the efficiency of communication among scheduling agents we suggest a rough capacity coordination model which supports to monitor participating agents and analyze the status of them. With this coordination mechanism, we can easily model coordination processes of multiple scheduling systems. In the future, we will apply this mechanism to shipbuilding domain and develop a prototype system which consists of a dock-scheduling agent, four assembly-plant-scheduling agents, and a meta-level coordination agent. A series of experiment using the real-world data will be performed to examine this mechanism.

A Model for Material Handling is an Elevator System

  • Kim, Seung-Nam
    • Journal of the Korean Operations Research and Management Science Society
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    • v.18 no.2
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    • pp.105-130
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    • 1993
  • This study deals with finding a schedule for the movement of a material handling device (elevator) in a manufacturing plant. Two different algorithm (Traveling Salesman Technique and Greedy Algorithm) are used in the scheduling of the elevators using a simulation technique to determine the proper method of scheduling the elevator movement. Based on the simulation analysis, we have found that the Greedy algorithm serves better than the algorithm based on Traveling Salesman technique for scheduling the movement of a material handling device in the manufacturing plant.

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Issues and approaches to spatial scheduling (공간 일정 계획의 이슈들과 접근방법)

  • 이경전;이재규
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1995.04a
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    • pp.758-759
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    • 1995
  • In large-scale industry such as shipbuilding, aircraft manufacturing, and construction industry etc., it is required to consider two or three-dimensional spatial availability as one of bottlenecked resource constraints. We call this kind of scheduling a spatial scheduling, which considers the dynamic spatial layouts of objects as well as the traditional resource constraints. Since 1991, we have researched on the spatial scheduling for shipbuilding plant (Lee & Lee, 1992; Lee et al., 1994, Lee et al., 1995). In this paper, we present the various issues of spatial scheduling for the researchers and developers attacking spatial scheduling problems.

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A Scheduling Support System for Non-identical Parallel Machine Lines (이종병렬기계생산의 일정계획지원 시스템)

  • 정남기;정민영
    • Korean Management Science Review
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    • v.17 no.2
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    • pp.67-73
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    • 2000
  • This paper describes a scheduling support system for a plant where the machine environment may be modeled as non-identical parallel machine lines (NPML). That is, there are a number of stages in series with various different-capability-machines at each stage. Arriving continuously are jobs with their specific due dates, processing times and candidate processing machines. We’ve developed a real-time scheduling module in conjunction with a supporting production information system which supplies necessary data to the module. This scheduling module is one of the 9 modules in this system, and is composed of both a scheduling interface and a production monitoring interface. This module allows users to generate many candidate schedules by selecting their business policies. The selective arguments which are available consist of allocation costs, batch sizes and machine selection intervals. They are now being implemented at a powder metallurgy plant.

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A Study on the Sway Control of a Crane Based on Gain-Scheduling Approach (Gain-Scheduling 기법을 이용한 크레인의 흔들림 제어에 관한 연구)

  • Kim, Young-Bok
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.7
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    • pp.53-64
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    • 2001
  • The gain-scheduling control technique is vary useful in the control problem incorporating time varying parameters which can be measured in real time. Based on these facts, in this paper the sway control problem of the pendulum motion of a container hanging on the trolly, which transports containers from a container ship to trucks, is considered. In the container crane control problem, suppressing the residual swing motion of the container at the end of acceleration, deceleration or the case of that the unexpected disturbance input exists is main issue. For this problem, in general, the trolley motion control strategy is introduced and applied. But, in this paper, we introduce and synthesize a new type of swing motion control system. In this control system, a small auxiliary mass is installed on the spreader. And the actuator reacts against the auxiliary mass, applying inertial control forces to the container to reduce the swing motion in the desired manner. In this paper, we assume that an plant parameter is varying and apply the gain-scheduling control technique design the anti-swing motion control system for the controlled plant. In this control system, the controller dynamics are adjusted in real-time according to time-varying plant parameters. And the simulation result shows that the proposed control strategy is shown to be useful to the case of time-varying system and, robust to disturbances like winds and initial sway motion.

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Implementation of Cable Drum Scheduling Algorithm for Productivity Enhancement of Power Plant Electrical Installations (발전소 전기설비의 생산성 향상을 위한 케이블 드럼 스케줄링 알고리즘 구현)

  • Lee, Yang-Sun;Park, Ki-Hong;Choi, Hyo-Beom;Oh, Ji-Hyun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.770-771
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    • 2015
  • In this paper, we proposed and implemented the automation of cable drum scheduling which is required a considerable construction cost for electrical equipment in power plant. Implemented cable drum scheduling can be reduced the calculation time of cable drum scheduling, and it is possible to minimize the consuming time of cable drum scheduling than conventional methods. Some experiments are conducted to verify the proposed method, and as a result, the automation of cable drum scheduling is well performed, enabling cables can be optimized and scheduled to fit the drum capacity with productivity enhancement of electrical installations.

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A Development of the Optimization Model for Reactive Scheduling Considering Equipment Failure (장치이상을 고려한 동적 생산계획 최적화 모델 개발)

  • Ha, Jin-Kuk;Lee, Euy Soo
    • Korean Chemical Engineering Research
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    • v.43 no.5
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    • pp.571-578
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    • 2005
  • We propose a new optimization framework for the reactive scheduling. The proposed rescheduling scheme is specially focused on how to generate rescheduling results when equipment failure occurs. The approach is based on a continuous-time problem representation that takes into account the schedule in progress, the updated information on the batches still to be processed, the present plant state, the deviations in plant parameters and the time data. To update the predictive scheduling, we used right shift rescheduling and total regeneration when equipment failure occurs. And, a practical solution to the rescheduling problem requires satisfaction of two often confliction measures: the efficiency measure that evaluates the satisfaction of a desired objective function value and the stability measure that evaluates the amount of change between the schedules before and after the disruption. In this paper, the efficiency is measured by the makespan of all jobs in the system. And, the stability is measured by the percentage change in makespan and the modified sequence deviation in the predictive scheduling and rescheduling.

A Scheduling Scheme for Flexible Flow Shop with Release Date and Due Date (시작시기와 납기를 고려하는 유연흐름공장의 일정계획)

  • Lee, J.H.;Kim, S.S.
    • IE interfaces
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    • v.11 no.3
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    • pp.1-13
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    • 1998
  • This paper addresses a scheduling scheme for Flexible Flow Shop(FFS) in the case that a factory is a sub-plant of an electronic device manufacturing plant. Under this environment, job orders for the sub-plants in the production route are generated together with job processing time bucket when the customer places orders for final product. The processing time bucket for each job is a duration from possible release date to permissible due date. A sub-plant modeled FFS should schedule these jobs orders within time bucket. Viewing a Printed Circuit Board(PCB) assembly line as a FFS, the developed scheme schedules an incoming order along with the orders already placed on the scheduled. The scheme consists of the four steps, 1)assigning operation release date and due date to each work cells in the FFS, 2)job grouping, 3)dispatching and 4)machine allocation. Since the FFS scheduling problem is NP-complete, the logics used are heuristic. Using a real case, we tested the scheme and compared it with the John's algorithm and other dispatching rules.

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