• Title, Summary, Keyword: scheduling

Search Result 4,502, Processing Time 0.09 seconds

Multi-Parameter Based Scheduling for Multi-user MIMO Systems

  • Chanthirasekaran, K.;Bhagyaveni, M.A.;Parvathy, L. Rama
    • Journal of Electrical Engineering and Technology
    • /
    • v.10 no.6
    • /
    • pp.2406-2412
    • /
    • 2015
  • Multi-user multi-input multi-output (MU-MIMO) system has attracted the 4th generation wireless network as one of core technique for performance enrichment. In this system rate control is a challenging problem and another problem is optimization. Proper scheduling can resolve these problems by deciding which set of user and at which rate the users send their data. This paper proposes a new multi-parameter based scheduling (MPS) for downlink multi-user multiple-input multiple-output (MU-MIMO) system under space-time block coding (STBC) transmissions. Goal of this MPS scheme is to offer improved link level performance in terms of a low average bit error rate (BER), high packet delivery ratio (PDR) with improved resource utilization and service fairness among the user. This scheme allows the set of users to send data based on their channel quality and their demand rates. Simulation compares the MPS performance with other scheduling scheme such as fair scheduling (FS), normalized priority scheduling (NPS) and threshold based fair scheduling (TFS). The results obtained prove that MPS has significant improvement in average BER performance with improved resource utilization and fairness as compared to the other scheduling scheme.

A Genetic Algorithm for Integration of Process Planning and Scheduling in a Job Shop (Job Shop 통합 일정계획을 위한 유전 알고리즘)

  • Park, Byung-Joo;Choi, Hyung-Rim;Kang, Moo-Hong
    • Journal of the Korean Operations Research and Management Science Society
    • /
    • v.30 no.3
    • /
    • pp.55-65
    • /
    • 2005
  • In recent manufacturing systems, most jobs may have several process plans, such as alternative sequence of operations, alternative machine etc. A few researches have addressed the necessity for the integration of process planning and scheduling function for efficient use of manufacturing resources. But the integration problem is very difficult and complex. Many prior researches considered them separately or sequentially. It introduces overlapping or partial duplications in solution efforts. In this paper, Integration problem of jobs with multiple process plans in a job shop environment Is addressed. In order to achieve an efficient integration between process planning and scheduling by taking advantage of the flexibility that alternative process plans offer, we designed GA(Genetic Algorithm)-based scheduling method. The performance of proposed GA is evaluated through comparing integrated scheduling with separated scheduling in real world company with alternative machines and sequences of operations. Also, a couple of benchmark problems are used to evaluate performance. The integrated scheduling method in this research can be effectively epplied to the real case.

The techniques of object-based reservation scheduling (객체에 근거한 예약 스케줄링 기법)

  • 김진봉;백청호
    • Journal of the Korea Computer Industry Society
    • /
    • v.5 no.2
    • /
    • pp.227-233
    • /
    • 2004
  • Complex scheduling problems are related to planning, scheduling, constraint satisfaction problems, object-oriented concepts, and agent systems. Human preference-driven scheduling technique was to solve complex scheduling problems using constraint satisfaction problems and object-oriented concepts. We have tried to apply human preference-driven scheduling technique to reservation problems. For customer's satisfaction, we have considered customer's preferences in the reservation scheduling. The technique of reservation scheduling proposed in this thesis is based on object-oriented concepts. 1'o consider the over all satisfaction, the events of every object are alloted to the board along its priority. Constraints to reservation scheduling are classified to global and local. The definition of board and information of every event are global constraints and the preferences to object's board slots are local constraints. We have applied look-ahead technology to reservation scheduling in order to minimize backtracking not to fail the allotment of events.

  • PDF

Analysis of Boundary Conditions for Activities' Relationships in Linear Scheduling Model (선형 공정계획 모델의 액티비티 관계의 경계조건 분석)

  • Ryu, Han-Guk;Kim, Tae-Hui
    • Korean Journal of Construction Engineering and Management
    • /
    • v.12 no.1
    • /
    • pp.23-32
    • /
    • 2011
  • Domestic leading construction companies has been establishing and performing TACT scheduling method, similar to linear scheduling model such as line of balance and repetitive schedule, and etc. in which repetitive construction works are involved like high-rise building. Linear scheduling model has been researched as a visual scheduling method presenting the work space and time information. Likewise scheduling constraints of CPM network such as finish-to-finish, start-to-start, finish-to-start, start-to-start, linear scheduling model also has the relationships constraints, namely boundary conditions, between activities. It is especially necessary to define the boundary conditions of the activities' relationships in order to apply the linear scheduling model to be compatible with the network schedule. Therefore, this research considers the boundary conditions between activities for establishing the linear scheduling model. This paper also applies the proposed boundary conditions to TACT schedule and then deduces the main considerations in order to establish and perform TACT schedule.

An Operating System Design and Development for Efficient Painting Process

  • Chung, Kuy-Hoon;Baek, Tae-Hyun;Park, Ju-Chull;Cho, Kyu-Kab
    • Proceedings of the Korean Operations and Management Science Society Conference
    • /
    • /
    • pp.183-187
    • /
    • 2000
  • In this study, we design a scheduling system for painting shop, called HYPOS(Hyundai heavy industry Painting shop Operating System) and develop a system implementing the design. The painting shop operations are currently scheduled manually by experts. Manual scheduling is a serious time consuming job and generally can not guarantee a full optimality. Building a traditional heuristic scheduling system lot this problem, however, is not promising because there are various kinds of constraints to be satisfied including space allocation of shipbuilding blocks in a painting cell. We, therefore, adopt a spatial scheduling approach and develop scheduling algorithms based on field-oriented scheduling heuristics and computational geometry. And we show that the algorithms can successfully be applied to the painting shop scheduling problem.

  • PDF

Feedrate Scheduling for High Speed Machining Based on an Improved Cutting Force Model (향상된 절삭력 모델을 이용한 고속 가공의 이송속도 스케줄링)

  • 이한울;고정훈;조동우
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.141-144
    • /
    • 2003
  • This paper proposes an analytical model of off-line feed rate scheduling to obtain an optimum feed rate for high speed machining. Off-line feed rate scheduling is presented as an advanced technology to regulate cutting forces through change of feed per tooth, which directly affects variation of uncut chip thickness. In this paper, the feed rate scheduling model was developed using a mechanistic cutting force model using cutting-condition-independent coefficients. First, it was verified that cutting force coefficients are not changed with respect to cutting speed. Thus, the feed rate scheduling model using the cutting-condition-independent coefficients can be applied to set the proper feed rates for high speed machining as well as normal machining. Experimental results show that the developed fred rate scheduling model makes it possible to maintain the cutting force at a desired level during high speed machining.

  • PDF

A rule-based scheduling system for automated machining

  • Ahn, Jaekyoung
    • Proceedings of the Korean Operations and Management Science Society Conference
    • /
    • /
    • pp.249-257
    • /
    • 1992
  • An automated machining system involves concurrent use of manufacturing resources, alternative process plans, and flexible routings. High investment in the installation of automated facilities requires an efficient scheduling system that is able to allocate the resources specified for operations over a scheduling horizon. The primary emphasis of this paper is to generate schedules that accurately reflect details of the automated environment and the objectives stated for the system. In this paper, a scheduling algorithm for automated machining is presented. Using the previous simulation research for this topic, a rule-based scheduling system is constructed. An architecture for an intelligent scheduling system is proposed, and the system has a high potential to provide efficient schedules based on the task-specific knowledge for the dynamic scheduling environment

  • PDF

A modified simulated annealing search algorithm for scheduling of chemical batch processes with CIS policy

  • Kim, Hyung-Joon;Jung, Jae-Hak
    • 제어로봇시스템학회:학술대회논문집
    • /
    • /
    • pp.319-322
    • /
    • 1995
  • As a trend toward multi-product batch processes is increasing in Chemical Process Industry (CPI), multi-product batch scheduling has been actively studied. But the optimal production scheduling problems for multi-product batch processes are known as NP-complete. Recently Ku and Karimi [5] have studied Simulated Annealing(SA) and Jung et al.[6] have developed Modified Simulated Annealing (MSA) method which was composed of two stage search algorithms for scheduling of batch processes with UIS and NIS. Jung et al.[9] also have studied the Common Intermediate Storage(CIS) policy which have accepted as a high efficient intermediate storage policy. It can be also applied to pipeless mobile intermediate storage pacilities. In spite of these above researches, there have been no contribution of scheduling of CIS policy for chemical batch processes. In this paper, we have developed another MSA for scheduling chemical batch processes with searching the suitable control parameters for CIS policy and have tested the this algorithm with randomly generated various scheduling problems. From these tests, MSA is outperformed to general SA for CIS batch process system.

  • PDF

A Parallel Genetic Algorithms for lob Shop Scheduling Problems (Job Shop 일정계획을 위한 병렬 유전 알고리즘)

  • 박병주;김현수
    • Journal of the Society of Korea Industrial and Systems Engineering
    • /
    • v.23 no.59
    • /
    • pp.11-20
    • /
    • 2000
  • The Job Shop Scheduling Problem(JSSP) is one of the most general and difficult of all traditional scheduling problems. The goal of this research is to develop an efficient scheduling method based on single genetic algorithm(SGA) and parallel genetic algorithm (PGA) to address JSSP. In this scheduling method, new genetic operator, generating method of initial population are developed and island model PGA are proposed. The scheduling method based on PGA are tested on standard benchmark JSSP. The results were compared with SGA and another GA-based scheduling method. The PGA search the better solution or improves average of solution in benchmark JSSP. Compared to traditional GA, the proposed approach yields significant improvement at a solution.

  • PDF

LSB 스케줄링기법의 소개

  • Park Chang Gyu;Kim Hyeon Jun
    • Proceedings of the Korean Operations and Management Science Society Conference
    • /
    • /
    • pp.944-948
    • /
    • 2002
  • In industrial production setting scheduling problems of detalied day-to-day operations are often ordeals to production practitioners. For those who have scheduling experience with the Gantt Chart, the job oriented heuristic scheduling has illustrated its merits in solving practically large stale scheduling problems. It schedules all operations of a job within a finite capacity before considering the next job. This paper introduces a new LSB (load smoothing backward) scheduling algorithm for the job oriented heuristic scheduling. Through the computer simulation in a hypothetical setting, this paper provides a comparison of LSB scheduling with existing algorithms and a guideline for selecting the suitable algorithm for certain industrial setting.

  • PDF