687 research outputs found

    A Note on Two-Agent Scheduling with Resource Dependent Release Times on a Single Machine

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    We consider a scheduling problem in which both resource dependent release times and two agents exist simultaneously. Two agents share a common single machine, and each agent wants to minimize a cost function dependent on its own jobs. The release time of each A-agent's job is related to the amount of resource consumed. The objective is to find a schedule for the problem of minimizing A-agent's total amount of resource consumption with a constraint on B-agent's makespan. The optimal properties and the optimal polynomial time algorithm are proposed to solve the scheduling problem

    Scheduling Jobs with Variable Job Processing Times on Unrelated Parallel Machines

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    m unrelated parallel machines scheduling problems with variable job processing times are considered, where the processing time of a job is a function of its position in a sequence, its starting time, and its resource allocation. The objective is to determine the optimal resource allocation and the optimal schedule to minimize a total cost function that dependents on the total completion (waiting) time, the total machine load, the total absolute differences in completion (waiting) times on all machines, and total resource cost. If the number of machines is a given constant number, we propose a polynomial time algorithm to solve the problem

    Cyclic scheduling of perishable products in parallel machine with release dates, due dates and deadlines

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    This paper deals with a realistic cyclic scheduling problem in the food industry environment in which parallel machines are considered to process perishable jobs with given release dates, due dates and deadlines. Jobs are subject to post-production shelf life limitation and must be delivered to retailers during the corresponding time window bounded by due dates and deadlines. Both early and tardy jobs are penalized by partial weighted earliness/tardiness functions and the overall problem is to provide a cyclic schedule of minimum cost. A mixed integer programming model is proposed and a heuristic solution beside an iterated greedy algorithm is developed to generate good and feasible solutions for the problem. The proposed MIP, heuristic and iterated greedy produce a series of solutions covering a wide range of cases from slow optimal solutions to quick and approximated schedules.Ruben Ruiz is partially supported by the Spanish Ministry of Economy and Competitiveness, under the project "RESULT - Realistic Extended Scheduling Using Light Techniques" with reference DPI2012-36243-C02-01 co-financed by the European Union and FEDER funds and by the Universitat Politecnica de Valencia, for the project MRPIV with reference PAID/2012/202.Shirvani, N.; Ruiz García, R.; Shadrokh, S. (2014). Cyclic scheduling of perishable products in parallel machine with release dates, due dates and deadlines. International Journal of Production Economics. 156:1-12. https://doi.org/10.1016/j.ijpe.2014.04.013S11215

    Hybrid Genetic Bees Algorithm applied to Single Machine Scheduling with Earliness and Tardiness Penalties

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    This paper presents a hybrid Genetic-Bees Algorithm based optimised solution for the single machine scheduling problem. The enhancement of the Bees Algorithm (BA) is conducted using the Genetic Algorithm's (GA's) operators during the global search stage. The proposed enhancement aims to increase the global search capability of the BA gradually with new additions. Although the BA has very successful implementations on various type of optimisation problems, it has found that the algorithm suffers from weak global search ability which increases the computational complexities on NP-hard type optimisation problems e.g. combinatorial/permutational type optimisation problems. This weakness occurs due to using a simple global random search operation during the search process. To reinforce the global search process in the BA, the proposed enhancement is utilised to increase exploration capability by expanding the number of fittest solutions through the genetical variations of promising solutions. The hybridisation process is realised by including two strategies into the basic BA, named as â\u80\u9creinforced global searchâ\u80\u9d and â\u80\u9cjumping functionâ\u80\u9d strategies. The reinforced global search strategy is the first stage of the hybridisation process and contains the mutation operator of the GA. The second strategy, jumping function strategy, consists of four GA operators as single point crossover, multipoint crossover, mutation and randomisation. To demonstrate the strength of the proposed solution, several experiments were carried out on 280 well-known single machine benchmark instances, and the results are presented by comparing to other well-known heuristic algorithms. According to the experiments, the proposed enhancements provides better capability to basic BA to jump from local minima, and GBA performed better compared to BA in terms of convergence and the quality of results. The convergence time reduced about 60% with about 30% better results for highly constrained jobs

    Short Duration Job Scheduling and Assignment using Staged Mixed Integer Programs

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    As part of large-scale digital transformation efforts, Atlantic Utility’s electric field force recently introduced a mobile work dispatch solution aimed at reducing inefficiencies associated with daily work. The application retired many of the manual, paper-based processes previously employed by field crews and supervisors to complete daily short-cycle (<6 hrs) jobs; it also introduced new capabilities that allow super- visors to review accumulated jobs in their operational region and strategize for their completion. Current operations find supervisors left with a long list of jobs to sift through when attempting to make daily work assignments and when scheduling work for one or more days in the future. Application users must manually identify jobs to schedule or assign while considering the distance to the job, required completion date, duration, and other factors. These factors contribute to the job priority level but without a simple way to aggregate these considerations into a clear set of prioritized jobs, supervisors are challenged to identify which work packets are highest priority and should be completed first. Daily scheduling and assignment is further complicated by the trade-off supervisors face when determining how to balance reduction of accumulated historical jobs with new jobs coming in at variable rates. This thesis formulates two proof-of-concept mixed integer programs that perform staged scheduling and assignment of short duration jobs. The objective functions include use of a metric indicative of a job’s total number of days past due or coming due. In this way, the formulations incorporate the real world trade-off supervisors face between historical and newly-created jobs subject to constraints on daily crew availability, increasing their utility as a future in-app aid for supervisors. Results of the scheduling stage over 2- to 6-day planning horizons indicate increased backlog reduction in comparison to naive or random strategies. Variation of user-defined inputs shows the scheduling formulation can be tuned to prioritize either jobs past due or those coming due in greater proportions, subject to the preferences of individual supervisors. When using both scheduling and assignment stages in sequence, results over 1- and 3-month simulated trials show consistently better performance in reducing job accumulation in comparison to historical records observed across operational barns of varying sizes. These results provide justification for a full operational pilot and recommendations for how to deploy production-ready algorithms are included in this thesis. They also suggest that greater improvement in barn operations is possible without assumption of increased crew capacity. Use of the staged formulations in the mobile work dispatch solution could introduce greater uniformity in how short duration jobs across the Atlantic Utility network are prioritized and completed, and may lead to enhanced customer service. These improvements could be realized through incorporation of these formulations as an automatic in-app aid to supervisors and field crews. Further, application of the staged approach to workforce allocation can be considered in industries outside utilities including those that involve logistics and delivery operations.M.B.A.S.M

    Scheduling of manufacturing systems based on extreme value theory and genetic algorithms

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.Includes bibliographical references (p. 143-154).by Velusamy Subramaniam.Ph.D

    Autonomous Finite Capacity Scheduling using Biological Control Principles

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    The vast majority of the research efforts in finite capacity scheduling over the past several years has focused on the generation of precise and almost exact measures for the working schedule presupposing complete information and a deterministic environment. During execution, however, production may be the subject of considerable variability, which may lead to frequent schedule interruptions. Production scheduling mechanisms are developed based on centralised control architecture in which all of the knowledge base and databases are modelled at the same location. This control architecture has difficulty in handling complex manufacturing systems that require knowledge and data at different locations. Adopting biological control principles refers to the process where a schedule is developed prior to the start of the processing after considering all the parameters involved at a resource involved and updated accordingly as the process executes. This research reviews the best practices in gene transcription and translation control methods and adopts these principles in the development of an autonomous finite capacity scheduling control logic aimed at reducing excessive use of manual input in planning tasks. With autonomous decision-making functionality, finite capacity scheduling will as much as practicably possible be able to respond autonomously to schedule disruptions by deployment of proactive scheduling procedures that may be used to revise or re-optimize the schedule when unexpected events occur. The novelty of this work is the ability of production resources to autonomously take decisions and the same way decisions are taken by autonomous entities in the process of gene transcription and translation. The idea has been implemented by the integration of simulation and modelling techniques with Taguchi analysis to investigate the contributions of finite capacity scheduling factors, and determination of the ‘what if’ scenarios encountered due to the existence of variability in production processes. The control logic adopts the induction rules as used in gene expression control mechanisms, studied in biological systems. Scheduling factors are identified to that effect and are investigated to find their effects on selected performance measurements for each resource in used. How they are used to deal with variability in the process is one major objective for this research as it is because of the variability that autonomous decision making becomes of interest. Although different scheduling techniques have been applied and are successful in production planning and control, the results obtained from the inclusion of the autonomous finite capacity scheduling control logic has proved that significant improvement can still be achieved

    Working Notes from the 1992 AAAI Spring Symposium on Practical Approaches to Scheduling and Planning

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    The symposium presented issues involved in the development of scheduling systems that can deal with resource and time limitations. To qualify, a system must be implemented and tested to some degree on non-trivial problems (ideally, on real-world problems). However, a system need not be fully deployed to qualify. Systems that schedule actions in terms of metric time constraints typically represent and reason about an external numeric clock or calendar and can be contrasted with those systems that represent time purely symbolically. The following topics are discussed: integrating planning and scheduling; integrating symbolic goals and numerical utilities; managing uncertainty; incremental rescheduling; managing limited computation time; anytime scheduling and planning algorithms, systems; dependency analysis and schedule reuse; management of schedule and plan execution; and incorporation of discrete event techniques
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