179,575 research outputs found

    Multi-mode resource constrained multi-project scheduling and resource portfolio problem

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    This paper introduces a multi-project problem environment which involves multiple projects with assigned due dates; with activities that have alternative resource usage modes; a resource dedication policy that does not allow sharing of resources among projects throughout the planning horizon; and a total budget. There are three issues to face when investigating this multiproject environment. First, the total budget should be distributed among different resource types to determine the general resource capacities which correspond to the total amount for each renewable resource to be dedicated to the projects. With the general resource capacities at hand, the next issue is to determine the amounts of resources to be dedicated to the individual projects. With the dedication of resources accomplished, the scheduling of the projects' activities reduces to the multi-mode resource constrained project scheduling problem (MRCPSP) for each individual project. Finally the last issue is the effcient solution of the resulting MRCPSPs. In this paper, this multi-project environment is modeled in an integrated fashion and designated as the Resource Portfolio Problem. A two-phase and a monolithic genetic algorithm are proposed as two solution approaches each of which employs a new improvement move designated as the combinatorial auction for resource portfolio and the combinatorial auction for resource dedication. Computational study using test problems demonstrated the effectiveness of the solution approach proposed

    Resource preference based improvement heuristics for resource portfolio problem

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    The multi-project problem environment under consideration involves multiple-projects with activities having alternative execution modes, a general resource budget and a resource management policy that does not allow sharing of resources among projects. The multi-project scheduling model for this problem environment is called Resource Portfolio Problem. There are three basic conceptual problems in RPP: (i) determining the general resource capacities from the given general resource budget (general resource capacities determination); (ii) dedication of the general resource capacities to projects (resource dedication) and finally (iii) scheduling of individual projects with the given resource dedications. In this study, different preference based improvement heuristics are proposed for general resource capacities determination and resource dedication conceptual problems. For general resource capacities determination, the current general resource capacity values are changed according to the resource preferences such that the resulting capacity state would be more preferable. Similarly for resource dedication, resource dedication values of projects are changed according to the preferences of projects for resources such that the resulting resource dedication state would be more preferable. These two improvement heuristics separates and couples the conceptual problems. Different preference calculation methods are proposed employing Lagrangian relaxation and linear relaxation of MRCPSP formulation

    Comparing Critical Chain Project Managemenet with Critical Path Method: A Case Study

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    Scheduling is a major task in project management. The current scheduling technique, Critical Path Method (CPM), has been widely applied for several decades, but a large number of projects fail to be completed on time and schedule delays occur in many projects. This raises question about the validity of the current project scheduling system. Critical Chain Project Management (CCPM), derived from Theory of Constraints, is a relatively new alternative approach toward scheduling projects. This study compared CCPM and CPM to determine which scheduling method delivers a shorter project duration and has a better usage of resources. A scheduling software called ProChain was used to reschedule a CPM based construction project using CCPM. The study concluded that the CCPM has the possibility to deliver shorter project duration and better resource usage in comparison to CPM. It was revealed that ProChain has limitation in the process of transforming a CPM schedule to a CCPM schedule. For example, ProChain treats any tasks without any predecessor as a project terminating task and puts a project buffer after it

    STUDI KOMPARATIF PENJADWALAN PROYEK KONSTRUKSI REPETITIF MENGGUNAKAN METODE PENJADWALAN BERULANG (RSM) DAN METODE DIAGRAM PRESEDEN (PDM)

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    Repetitive project activities require scheduling instrument which can facilitate unbreakable resources flow from one to the next unit. CPM which has been widely recognized as a tough project scheduling method to handle complex and has many branchesl networks, apparently become less effective if we used it to schedule repetitive project. Like wise the PDM usefulness in a project relatively collided with it’s limited ability to maintain work continuity for existing worker teams.What we want to inform in this paper is introducing a new alternative method that is RSM . RSM is a method that guarantee the unbreakable resources usage, also applicable for both repetitive vertical and horizontal project. Considered from the expense of total labor fee, RSM are more cost-saving than PDM if the labor arrangement is adapted to work specializatio

    Multi-mode resource constrained multi-project scheduling and resource portfolio problem

    Get PDF
    This paper introduces a multi-project problem environment which involves multiple projects with assigned due dates; activities that have alternative resource usage modes; a resource dedication policy that does not allow sharing of resources among projects throughout the planning horizon; and a total budget. Three issues arise when investigating this multi-project environment. First, the total budget should be distributed among different resource types to determine the general resource capacities, which correspond to the total amount for each renewable resource to be dedicated to the projects. With the general resource capacities at hand, the next issue is to determine the amounts of resources to be dedicated to the individual projects. The dedication of resources reduces the scheduling of the projects' activities to a multi-mode resource constrained project scheduling problem (MRCPSP)for each individual project. Finally, the last issue is the ecient solution of the resulting MRCPSPs. In this paper, this multi-project environment is modeled in an integrated fashion and designated as the Resource Portfolio Problem. A two-phase and a monolithic genetic algorithm are proposed as two solution approaches, each of which employs a new improvement move designated as the combinatorial auction for resource portfolio and the combinatorial auction for resource dedication. A computational study using test problems demonstrated the effectiveness of the solution approach proposed. Keywords: Project scheduling, resource portfolio problem, multi-project scheduling, resource dedication, resource preference

    Optimizing Multiple-Resources Leveling in Multiple Projects Using Discrete Symbiotic Organisms Search

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    Resource leveling is used in project scheduling to reduce fluctuation in resource usage over the period of project implementation. Fluctuating resource usage frequently creates the untenable requirement of regularly hiring and firing temporary staff to meet short-term project needs. Construction project decision makers currently rely on experience-based methods to manage fluctuations. However, these methods lack consistency and may result in unnecessary waste of resources or costly schedule overruns. This research introduces a novel discrete symbiotic organisms search for optimizing multiple resources leveling in the multiple projects scheduling problem (DSOS-MRLMP). The optimization model proposed is based on a recently developed metaheuristic algorithm called symbiotic organisms search (SOS). SOS mimics the symbiotic relationship strategies that organisms use to survive in the ecosystem. Experimental results and statistical tests indicate that the proposed model obtains optimal results more reliably and efficiently than do the other optimization algorithms considered. The proposed optimization model is a promising alternative approach to assisting project managers in handling MRLMP effectively

    Multi-agent Learning by Trial and Error for Resource Leveling during Multi-Project (Re)scheduling

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    In a multi-project context within enterprise networks, reaching feasible solutions to the (re)scheduling problem represents a major challenge, mainly when scarce resources are shared among projects. The multi-project (re)scheduling must achieve the most efficient possible resource usage without increasing the prescribed project constraints, considering the Resource Leveling Problem (RLP), whose objective is to level the consumption of resources shared in order to minimize their idle times and to avoid overallocation conflicts. In this work, a multi-agent solution that allows solving the Resource Constrained Multi-project Scheduling Problem (RCMPSP) and the Resource Investment Problem is extended to incorporate indicators on agents? payoff functions to address the Resource Leveling Problem in a decentralized and autonomous way, through decoupled rules based on Trial-and-Error approach. The proposed agent-based simulation model is tested through a set of project instances that vary in their structure, parameters, number of resources shared, etc. Results obtained are assessed through different scheduling goals, such as project total duration, project total cost and leveling resource usage. Our results are far better compared to the ones obtained with alternative approaches. This proposal shows that the interacting agents that implement decoupled learning rules find a solution which can be understood as a Nash equilibrium.Fil: Tosselli, Laura. Universidad Tecnológica Nacional; ArgentinaFil: Bogado, Verónica Soledad. Universidad Tecnológica Nacional; ArgentinaFil: Martínez, Ernesto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo y Diseño. Universidad Tecnológica Nacional. Facultad Regional Santa Fe. Instituto de Desarrollo y Diseño; Argentin

    Project Work Uncertainties and the Boundaries of the Firm

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    The effective use of resources in an economy requires both that they are available where and when most needed and that they are kept employed as fully and effectively as possible. A lack of certainty over future resource needs within firms brings these two requirements into conflict. It is argued that the firm and the market offer alternative means of handling this trade-off. The market switches resource services between customers to keep specialist resources employed. However, this does not guarantee the firm that a resource will always be available when needed. The firm may therefore internalise resources, switching them between different tasks to keep them employed and to make their specialist capabilities available where most needed. Idiosyncratic advantages form an important part of the theory, often severely exacerbating resource availability issues. A model of resource planning in a project with uncertain task durations is presented to illustrate the problem faced by the firm.Project, Organisation, Uncertainty, Resources, Scheduling, Internalisation

    Time-Cost Tradeoff and Resource-Scheduling Problems in Construction: A State-of-the-Art Review

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    Duration, cost, and resources are defined as constraints in projects. Consequently, Construction manager needs to balance between theses constraints to ensure that project objectives are met. Choosing the best alternative of each activity is one of the most significant problems in construction management to minimize project duration, project cost and also satisfies resources constraints as well as smoothing resources. Advanced computer technologies could empower construction engineers and project managers to make right, fast and applicable decisions based on accurate data that can be studied, optimized, and quantified with great accuracy. This article strives to find the recent improvements of resource-scheduling problems and time-cost trade off and the interacting between them which can be used in innovating new approaches in construction management. To achieve this goal, a state-of-the-art review, is conducted as a literature sample including articles implying three areas of research; time-cost trade off, constrained resources and unconstrained resources. A content analysis is made to clarify contributions and gaps of knowledge to help suggesting and specifying opportunities for future research
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