This paper is regarding the Particle Swarm Optimization (PSO)-based approach for the solution of the resource-constrained project scheduling problem with the purpose of minimizing cost. In order to evaluate the perfor...
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This paper is regarding the Particle Swarm Optimization (PSO)-based approach for the solution of the resource-constrained project scheduling problem with the purpose of minimizing cost. In order to evaluate the performance of the PSO based approach for the resource-constrained project scheduling problem, computational analyses are given. As per the results the application of PSO to projectscheduling is achievable.
The objective of this research was to schedule project activities based on maximum net present value (NPV) and minimum duration. A new hybrid heuristic based on the combination of minimum late start (MLS) and shortest...
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The objective of this research was to schedule project activities based on maximum net present value (NPV) and minimum duration. A new hybrid heuristic based on the combination of minimum late start (MLS) and shortest processing time (SPT) priority-rules heuristics was developed. The new late start and shortest processing time (LSSPT) heuristic was tested using 60 problems of the Patterson set, and results compared with 4 other heuristics. To test all 5 previous heuristics, 5 computer programs were developed. Statistical analysis was performed. Results indicate that the new heuristic produced better and encouraging results.
Multi-skilled projectscheduling concerns the assignment of multi-skilled resources to activities and the scheduling of these activities in order to minimise the project makespan. Since the resources in these problems...
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Multi-skilled projectscheduling concerns the assignment of multi-skilled resources to activities and the scheduling of these activities in order to minimise the project makespan. Since the resources in these problems can be discerned based on their mastered categorical skills, they are considered to be individual entities (human beings) rather than a general class or type of resources. Therefore, researchers have been looking into multi-skilled resources to investigate which other characteristics differentiate them from one another. A main line of research in the last years studies the incorporation of hierarchical skills and their impact on the decision-making in scheduling problems. Hierarchical skills indicate the level at which resources can perform their different skills. In this paper, we present six multi-skilled resource-constrained project scheduling problems with hierarchical skills. In each of these problems, the hierarchical skills have a different impact on the project and its objectives. Solutions are constructed using a solution framework where new problem-specific local searches are embedded in a genetic algorithm. This new framework is tested on existing data from the literature. Computational experiments compare the quality of the solution approaches and the local searches to an integer programming solver. Furthermore, the principal features and tendencies of each problem are discussed. Finally, best-known solutions and lower bounds for all presented problems will be provided.
This research introduces a problem called resource-constrained project scheduling problem with alternative activity chains, which is inspired from projectscheduling practice. An AND-OR project network representation ...
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This research introduces a problem called resource-constrained project scheduling problem with alternative activity chains, which is inspired from projectscheduling practice. An AND-OR project network representation is designed for the problem and then an integer linear program is developed. An extended simulated annealing algorithm is proposed to solve the large-scale problem efficiently, which consists of new activity-selection list solution presentation, schedule generation scheme and neighbor generation mechanism. Computational experiments are carried out to validate the proposed model and to evaluate the performance of the proposed algorithm.
Minimizing both project time and cost is an important matter in today's competitive environment. Therefore trade-off between project time and cost is necessary. In projects, each activity can be started at differe...
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Minimizing both project time and cost is an important matter in today's competitive environment. Therefore trade-off between project time and cost is necessary. In projects, each activity can be started at different time points, depending on its precedence relationship and resource availability. Also cost and duration of the activities could be changed depending on the allocated resources. In addition, another strategy that affects the project total time and cost is resource leveling, which is applied to reduce excessive fluctuations in the resource usage. In this paper multi-mode resource-constrained project scheduling problem (MRCPSP), discrete time-cost trade-off problem (DTCTP) and also resource allocation and resource leveling problem (RLP) are considered simultaneously. This paper presents the multi-mode resource-constrained discrete time-cost-resource optimization (MRC-DTCRO) model in order to select starting the time and the execution mode of each activity satisfying all the project constraints. To solve these problems, non-domination based genetic algorithm (NSGA-II) is employed to search for the non-dominated solutions considering total project time, cost, and resources moment deviation as three objectives. The results of MRC-DTCRO model presented in this paper show that adding the resource leveling capability to the previously developed multi-mode resource-constrained discrete time-cost trade-off problem (MRC-DTCTP) models provides more practical solutions in terms of resource allocation and leveling, which makes this research applicable to both construction industry and researchers. (C) 2012 Elsevier B.V. All rights reserved.
In this paper we study the resource-constrained project scheduling problem with weighted earliness-tardinesss penalty costs. project activities are assumed to have a known deterministic due date, a unit earliness as w...
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In this paper we study the resource-constrained project scheduling problem with weighted earliness-tardinesss penalty costs. project activities are assumed to have a known deterministic due date, a unit earliness as well as a unit tardiness penalty cost and constant renewable resource requirements. The objective is to schedule the activities in order to minimize the total weighted earliness-tardinesss penalty cost of the project subject to the finish-start precedence constraints and the constant renewable resource availability constraints. With these features the problem becomes highly attractive in just-in-time environments. We introduce a depth-first branch-and-bound algorithm which makes use of extra precedence relations to resolve resource conflicts and relies on a fast recursive search algorithm for the unconstrained weighted earliness-tardinesss problem to compute lower bounds. The procedure has been coded in Visual C++, version 4.0 under Windows NT. Both the recursive search algorithm and the branch-and-bound procedure have been validated on a randomly generated problem set.
Offshore engineering construction projects are large and complex,having the characteristics of multiple execution modes andmultiple resource *** complex internal scheduling processes can be regarded as resourceconstra...
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Offshore engineering construction projects are large and complex,having the characteristics of multiple execution modes andmultiple resource *** complex internal scheduling processes can be regarded as resourceconstrainedprojectscheduling problems(RCPSPs).To solve RCPSP problems in offshore engineering construction more rapidly,a hybrid genetic algorithmwas *** solve the defects of genetic algorithms,which easily fall into the local optimal solution,a local search operation was added to a genetic algorithm to defend the offspring after crossover/***,an elitist strategy and adaptive operators were adopted to protect the generated optimal solutions,reduce the computation time and avoid premature convergence.A calibrated function method was used to cater to the roulette rules,and appropriate rules for encoding,decoding and crossover/mutation were ***,a simple network was designed and validated using the case study of a real offshore *** performance of the genetic algorithmand a simulated annealing algorithmwas compared to validate the feasibility and effectiveness of the approach.
This paper presents a novel Constraint Programming (CP) approach to obtain strong lower bounds for the Job Shop scheduling Problem (JSSP) under the makespan criterion. Our approach comprises two phases. In the first p...
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This paper presents a novel Constraint Programming (CP) approach to obtain strong lower bounds for the Job Shop scheduling Problem (JSSP) under the makespan criterion. Our approach comprises two phases. In the first phase, a relaxation of the original problem is solved, while in the second phase, this relaxation is iteratively tightened until a time limit is reached or no better bounds are found. We tested our procedure with 80 JSSP open instances, and the results validated our approach as we were able to find 7 new lower bounds and prove optimality in one instance.
This paper deals with the weighted earliness-tardiness resource-constrained project scheduling problem with minimum and maximum time lags (WET-RCPSP/max). The problem consists of scheduling the activities of a project...
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This paper deals with the weighted earliness-tardiness resource-constrained project scheduling problem with minimum and maximum time lags (WET-RCPSP/max). The problem consists of scheduling the activities of a project subject to prescribed resource and temporal constraints such that the total weighted deviation of the activities' completion times from prescribed due dates is minimized. Key applications are planning of just-in-time production and reactive scheduling. For the (approximative) solution of the WET-RCPSP/max, we present a population-based iterated-local-search heuristic. We also report the results of an experimental performance analysis where this heuristic outperformed state-of-the-art methods.
Construction companies are required to employ effective methods of project planning and scheduling in today's competitive environment. Time and cost are critical factors in project success, and they can vary based...
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Construction companies are required to employ effective methods of project planning and scheduling in today's competitive environment. Time and cost are critical factors in project success, and they can vary based on the type and amount of resources used for activities, such as labor, tools, and materials. In addition, resource leveling strategies that are used to limit fluctuations in a project's resource consumption also affect project time and cost. The multi-mode resource-constrained discrete-time-cost-resource optimization (MRC-DTCRO) is an optimization tool that is developed for scheduling of a set of activities involving multiple execution modes with the aim of minimizing time, cost, and resource moment. Moreover, uncertainty in cost should be accounted for in project planning because activities are exposed to risks that can cause delays and budget overruns. This paper presents a fuzzy-multi-mode resource-constrained discrete-time-cost-resource optimization (F-MRC-DTCRO) model for the time-cost-resource moment tradeoff in a fuzzy environment while satisfying all the project constraints. In the proposed model, fuzzy numbers are used to characterize the uncertainty of direct cost of activities. Using this model, different risk acceptance levels of the decision maker can be addressed in the optimization process. A newly developed multi-objective optimization algorithm called ENSCBO is used to search non-dominated solutions to the fuzzy multi-objective model. Finally, the developed model is applied to solve a benchmark test problem. The results indicate that incorporating the fuzzy structure of uncertainty in costs to previously developed MRC-DTCRO models facilitates the decision-making process and provides more realistic solutions.
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