• 산업공학
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• 제16권3호
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• pp.332-343
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• 2003

This paper deals with pre-erection scheduling and erection scheduling in shipbuilding. Among shipbuilding scheduling, the ship erection scheduling in a dock is one of the most important since the dock is the most critical resource in a shipyard. However, it is more reasonable to consider pre-erection scheduling and erection scheduling as unified because they compete with the common constrained resources such as labor, crane, space, and so on. It is very hard to consider two scheduling problems simultaneously, and hence, we approach them sequentially. At first, we propose space resource leveling heuristics in pre-erection scheduling given erection date. And then, considering the manpower resource determined by pre-erection scheduling, we also propose manpower resource leveling heuristics in erection scheduling. Various experimental results with real world data show that the proposed heuristics have good performance in terms of scheduling quality and time.

• International Journal of Computer Science & Network Security
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• 제23권7호
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• pp.165-170
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• 2023

Scheduling algorithms plays a significant role in optimizing the CPU in operating system. Each scheduling algorithms schedules the processes in the ready queue with its own algorithm design and its properties. In this paper, the performance analysis of First come First serve scheduling, Non preemptive scheduling, Preemptive scheduling, Shortest Job scheduling and Round Robin algorithm has been discussed with an example and the results has been analyzed with the performance parameters such as minimum waiting time, minimum turnaround time and Response time.

• Journal of Communications and Networks
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• 제15권6호
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• pp.589-600
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• 2013

In this paper, we propose a new feedback scheme called mode selection-based feedback by scheduling probability prediction (SPP-MF) for channel state feedback in OFDMA downlink system. We design the scheme such that it determines the more desirable feedback mode among selective feedback by scheduling probability prediction (SPP-SF) mode and bitmap feedback by scheduling probability prediction (SPP-BF) mode, by calculating and comparing the throughputs of the two modes. In both feedback modes, each user first calculates the scheduling probability of each subchannel (i.e., the probability that a user wins the scheduling competition for a subchannel) and then forms a feedback message based on the scheduling probability. Specifically, in the SPP-SF mode, each user reports the modulation and coding scheme (MCS) levels and indices of its best S subchannels in terms of the scheduling probability. In the SPP-BF mode, each user determines its scheduling probability threshold. Then, it forms a bitmap for the subchannels according to the scheduling probability threshold and sends the bitmap along with the threshold. Numerical results reveal that the proposed SPP-MF scheme achieves significant performance gain over the existing feedback schemes.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.917-923
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• 2005

Scheduling is one of the main functions in construction project to determine the sequence of activities necessary to complete a project. The scheduling techniques provide important information crucial to a project's success. Highway construction project the paving activity can be considered a linear activity. Linear scheduling technique may be better suited for linear projects than other scheduling techniques. A new type of scheduling in linear project is calling Linear Scheduling Model (LSM). The Project monitoring and controlling is very ease to identify that all the stage of linear project and have more advantages.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권1호
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• pp.29-35
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• 2004

Locomotive scheduling in railway systems experiences many difficulties because of the complex interrelations among resources, knowledge and various constraints. Artificial intelligence technology has been applied to solve these scheduling problems. These technologies have proved to be efficient in representing knowledge and rules for complex scheduling problems. In this paper, we have applied the CSP (Constraints Satisfaction Problems) programming technique, one of the AI techniques, to solve the problems associated with locomotive scheduling. This method is more effective at solving complex scheduling problems than available mathematical programming techniques. The advanced locomotive scheduling system using the CSP programming technique is realized based on the actual timetable of the Saemaul type train on the Kyong-bu line. In this paper, an overview of the CSP programming technique is described, the modeling of domain and constraints is represented and the experimental results are compared with the real-world existing schedule. It is verified that the scheduling results by CSP programming are superior to existing scheduling performed by human experts. The executing time for locomotive scheduling is remarkably reduced to within several decade seconds, something requiring several days in the case of locomotive scheduling by human experts.

• 지능정보연구
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• 제17권4호
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• pp.213-226
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• 2011

글로벌 공급사슬 환경에서 글로벌하게 분산 조달, 생산, 유통하게 됨에 따라 전체 공급사슬의 스케줄을 최적화하기 위해서 공급사슬상의 개별 기업 혹은 공장의 스케줄링 최적화뿐만 아니라 각 개별 기업 혹은 공장의 스케줄을 긴밀하게 연계하는 것이 필요하게 되었다. 이는 경쟁과 협력을 동시에 하는 개별 기업 혹은 공장을 개별 에이전트로 보고 각 에이전트간 커뮤니케이션을 통해 개별 에이전트가 관할하는 스케줄러의 스케줄을 조정함으로써 가능해진다. 하지만 전통적인 스케줄링 연구는 개별 스케줄러의 최적화에 집중되어 있고, 에이전트 연구는 스케줄링 도메인에 적용한 예가 제한적이며 이 예도 개별 스케줄러 내의 최적화에 적용하거나 실제 현장 문제가 아닌 실험실 문제 수준에 그치고 있다. 따라서 본 연구에서는 전체 글로벌 공급사슬 스케줄의 최적화를 위해 개별 기업 혹은 공장 스케줄러의 스케줄링을 연계하는 경쟁협력 스케줄링을 위한 에이전트 기반 플랫폼을 구축하였다. 글로벌 공급사슬에서 경쟁협력 스케줄링을 위한 에이전트 기반 플랫폼을 구축하기 위해 첫째, 경쟁협력 스케줄링 분류 체계를 확립하고, 둘째, 경쟁협력 스케줄링을 위한 에이전트를 설계하고, 셋째, 경쟁협력 스케줄링을 위한 지식기반 의사결정 모델을 개발한 후, 넷째 조선산업에 적용 가능한 프로토타입 시스템을 개발했다. 이를 통해 글로벌 공급사슬상의 전체 스케줄의 품질과 에이전트간 커뮤니케이션의 노력에 대한 균형점을 찾을 수 있다. 이를 통해 공급사슬내 개별 기업 혹은 공장의 부분 최적화를 극복할 수 있는 대안을 제시할 것으로 기대한다.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.744-747
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• 2005

The AEC (Architecture/Engineering/Construction) industry is facing a competitive world after it entered into the 21^st century. Due to improper planning and scheduling, the construction projects face severe delays in completion. Most of the present day construction organisations operate in multiple project environments where more than one projects are to be managed simultaneously. But the advantages of planning and scheduling as multiple projects have not been utilized by these organisations. Change in multi-project planning and scheduling is inevitable and often frequent, therefore the traditional planning and scheduling approaches are no more feasible in scheduling multiple construction projects. The traditional scheduling tools like CPM and PERT do not offer any help in scheduling in a resource-constrained environment. This necessitated a detailed study to model the environment realistically and to make the allocation of limited resources flexible and efficient. This paper delineates about the proactive model which will help the project managers for scheduling the multiple construction projects.

• Journal of Information Technology Applications and Management
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• 제19권1호
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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.

• 한국정보과학회논문지:시스템및이론
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• 제31권1_2호
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• pp.95-101
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• 2004

이질적인 계산자원들로 구성된 분산 컴퓨팅 환경에서 의존성이 존재하지 않는 독립적인 작업들을 자원들에 배치하기 위한 방법은 NP-Complete 문제로 알려져 있다［1］. 이질적인 자원으로 구성된 시스템의 대표적인 예가 GRID［2］이다. 현재까지 그리드 시스템에서 스케줄링 문제를 풀기 위한 다양한 휴리스틱 스케줄링 방법이 연구되어 왔다［1,3,4,5］. 스케줄링 방법은 정적인 방법과 동적인 방법으로 나뉘어진다. 동적 스케줄링 방법은 작업의 선후 관계를 예측할 수 없는 상황에서 사용되며 동적 스케줄링 방법은 스케줄링 시기에 따라 온라인방식과 배치방식으로 나뉘어진다［1,6］. 본 논문에서는 새로운 온라인 휴리스틱 스케줄링 알고리즘을 제안하였으며 제안된 스케줄링 알고리즘의 성능이 기존의 스케줄링 알고리즘의 성능보다 뛰어남을 시뮬레이션을 통하여 보였다.

• Industrial Engineering and Management Systems
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• 제11권4호
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• pp.310-330
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• 2012

Scheduling is an important tool for a manufacturing system, where it can have a major impact on the productivity of a production process. In manufacturing systems, the purpose of scheduling is to minimize the production time and costs, by assigning a production facility when to make, with which staff, and on which equipment. Production scheduling aims to maximize the efficiency of the operation and reduce the costs. In order to find an optimal solution to manufacturing scheduling problems, it attempts to solve complex combinatorial optimization problems. Unfortunately, most of them fall into the class of NP-hard combinatorial problems. Genetic algorithm (GA) is one of the generic population-based metaheuristic optimization algorithms and the best one for finding a satisfactory solution in an acceptable time for the NP-hard scheduling problems. GA is the most popular type of evolutionary algorithm. In this survey paper, we address firstly multiobjective hybrid GA combined with adaptive fuzzy logic controller which gives fitness assignment mechanism and performance measures for solving multiple objective optimization problems, and four crucial issues in the manufacturing scheduling including a mathematical model, GA-based solution method and case study in flexible job-shop scheduling problem (fJSP), automatic guided vehicle (AGV) dispatching models in flexible manufacturing system (FMS) combined with priority-based GA, recent advanced planning and scheduling (APS) models and integrated systems for manufacturing.