• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권12호
• /
• pp.5694-5711
• /
• 2017

The technology of cloud computing is growing very quickly, thus it is required to manage the process of resource allocation. In this paper, load balancing algorithm based on honey bee behavior (LBA_HB) is proposed. Its main goal is distribute workload of multiple network links in the way that avoid underutilization and over utilization of the resources. This can be achieved by allocating the incoming task to a virtual machine (VM) which meets two conditions; number of tasks currently processing by this VM is less than number of tasks currently processing by other VMs and the deviation of this VM processing time from average processing time of all VMs is less than a threshold value. The proposed algorithm is compared with different scheduling algorithms; honey bee, ant colony, modified throttled and round robin algorithms. The results of experiments show the efficiency of the proposed algorithm in terms of execution time, response time, makespan, standard deviation of load, and degree of imbalance.

• 제어로봇시스템학회논문지
• /
• 제6권5호
• /
• pp.426-432
• /
• 2000

A novel mixed-integer linear programming model for the short-term scheduling of a sequential multipurpose batch plant is addressed. First, a time slot domain to each unit is introduced. By assigning each time slot to a product, we obtain the production sequence that minimizes makespan. For multiple-unit assignment problem where a few parallel units with the same function exist, production paths are defined for the distinction of the same stage with a different unit. As a second issue, the model adapted for sequence dependent changeover is presented. For a time slot of a unit, if a product is assigned to the time slot and a different product is assigned to the adjacent time slot, the changeover time considering this situation is included. The performance of the proposed models are illustrated through two examples.

• 대한산업공학회지
• /
• 제40권3호
• /
• pp.305-312
• /
• 2014

This research deals with a problem that minimizes makespan in a non-identical parallel machine system with sequence and machine dependent setup times and machine dependent processing times. We first present a new mixed integer programming formulation for the problem, and using this formulation, one can easily find optimal solutions for small problems. However, since the problem is NP-hard and the size of a real problem is large, we propose four heuristic algorithms including genetic algorithm based heuristics to solve the practical big-size problems in a reasonable computational time. To assess the performance of the algorithms, we conduct a computational experiment, from which we found the heuristic algorithms show different performances as the problem characteristics are changed and the simple heuristics show better performances than genetic algorithm based heuristics for the case when the numbers of jobs and/or machines are large.

• 대한산업공학회지
• /
• 제43권1호
• /
• pp.1-11
• /
• 2017

Stochastic resource-constrained project scheduling problem is an extension of resource-constrained project scheduling problem such that activity duration has stochastic nature. In real situation where activity duration is not known until the activity is finished, open-loop based static policies such as activity-based policy and priority-based policy will not well cope with duration variability. Then, a dynamic policy based on closed-loop decision making will be regarded as an alternative toward achievement of minimal makespan. In this study, a dynamic policy designed to select activities to start at each decision time point is illustrated. The performance of static and dynamic policies based on variable neighborhood search is evaluated under the discrete-event simulation environment. Experiments with J120 sets in PSPLIB and several probability distributions of activity duration show that the dynamic policy is superior to static policies. Even when the variability is high, the dynamic policy provides stable and good solutions.

• 한국경영과학회지
• /
• 제17권3호
• /
• pp.47-57
• /
• 1992

The purpose of this paper is to improve the operation performance of unit-load Automated Guided Vehicles (AGV's) used as a carrier and mobile workstation in a flow-shop type flexible manufacturing system. An algorithm is developed to determine the optimal job sequence which minimizes the vehicle idle time on the line and the production makespan by the use of the entering interval and travel time between workcenters. An entering times of AGV's and the minimum number of AGV's required are calculated by optimal job sequence. When the numbe rof AGV's is limited, enterling times of AGV's are adjusted to maximize the efficient use of vehicles. A numerical example is given to illustrate the application of the algorithm.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1991년도 춘계공동학술대회 발표논문 및 초록집; 전북대학교, 전주; 26-27 Apr. 1991
• /
• pp.77-89
• /
• 1991

One of the important problems concerning the efficient operation of an automated manufacturing system is the flow control problem. Most research papers about scheduling and control of a FMS consider fabrication, machining and assembly independently. In this paper an effective flow control strategy for a FMS with an assembly subsystem which may be called FMAS (Flexible Machining and Assembly System) is designed using the operation-oriented and, combined Push and Pull control method. The flow control system to be described here could meet production demands with a minimum makespan while satisfying assigned due-dates and keeping a low volume of work-in-process at the same time. The control mechanism also considers machine failures and rush jobs.

• 한국국방경영분석학회지
• /
• 제22권2호
• /
• pp.153-165
• /
• 1996

This paper presents an order releasing algorithm for an AMS. Order release policy determine order releasing time to shop floor so as to improve order management and shop performance. The proposed order releasing algorithm can cope with the dynamic environment of orders(e.g. change or cancel of order) flexibly and fastly, by processing individual order and exchanging the information(e.g. compeletion time or lateness of order, etc) with customer. And the objective of the order releasing algorithm is the observance of the due-date, therefore, it can provide customer with a reliability of order. Computer simulation is used to obtain the makespan of order which is the input data of the order releasing algorithm. The eight candidate part dispatching rules are simulated to selected an effective part dispatching rule for the computer simulation. By using the best effective part dispatching rule, the computer simulation is conducted to determine order releasing time.

• 대한산업공학회지
• /
• 제11권2호
• /
• pp.57-73
• /
• 1985

Group scheduling problem in a multi-stage manufacturing system is reviewed and two heuristic procedures for minimizing the makespan are developed by employing the methods of flow shop sequencing heuristics with a slight modification. The comparisons among the five heuristics, three previously reported heuristics and two heuristics suggested by this study, are made on different problem sizes. The computational results indicate that NEH-GS method gives better group schedules than the other heuristics tested, but its computation time increases rapidly as the problem size increases. On the other hand, CDS-GS method provides relatively good group schedules with less computation time compared with NEH-GS method.

• 경영과학
• /
• 제11권1호
• /
• pp.23-37
• /
• 1994

This paper discusses the methodology for the operational performance of unit-load automated guided vehicles(AGVs) in a flow-shop-type flexible machining and assembly systems (FM/AS). Throughout the paper, AGVs are working as a carrier and mobile workstation. For a double-loop FM/AS, in which one loop is dedicated to machining and the other to assembly, three AGV operating strategies are proposed. Considering the entering interval and travel time of AGVs between workcenters, the strategies are developed to determine the best job sequence which minimizes the makespan and vehicle idle time. Entering times of AGVs and the required minimum number of AGVs are obtained on the basis of the best job sequence. When the number of AGVs are limited, entering times of AGVs are adjusted to maximize the utilization of AGVs.

• International Journal of Quality Innovation
• /
• 제2권2호
• /
• pp.101-120
• /
• 2001

In this paper jobshop scheduling problem was considered on automated manufacturing systems with the closed loop and unidirectional material handling system. The objective of this research is to develop and evaluate heuristic scheduling procedures to improve productivity by minimizing makespan. Especially travel time of material handling system as well as processing time was considered in the proposed algorithms, A new heuristic algorithms are proposed and illustrates the proposed algorithm. The heuristic algorithms are implemented for various cases. The results show that the proposed algorithms provide better solutions in productivity, frequency, job waiting time and the number of waiting jobs than the random scheduling algorithm.