Table 9 - uploaded by Tomasz Błaszczyk
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The aim of this research was the trial of modelling and optimizing the time-cost trade-offs in project planning problem with
taking into account the behavioral impact of performers’ (or subcontractors’) estimations of basic activity parameters. However,
such a model must include quantitative measurements of budget and duration, so we proposed to qu...
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The aim of this research was the trial of modelling and optimizing the time-cost trade-offs in project planning problem with taking into account the behavioral impact of performers' (or subcontractors') estimations of basic activity parameters. However, such a model must include quantitative measurements of budget and duration, so we proposed to qu...
Citations
... At the core of our proposed methodology lies the concept of critical chain by Goldratt [16] supported with the idea of the cost buffer with incentive fund described by Błaszczyk and Nowak [11]. This approach was formalized by Błaszczyk et al. [2] with introducing the matrix of factors influencing standard projects' evaluation criteria of duration and cost, and by developing work effort estimations for each projects' activity by Błaszczyk and Błaszczyk in [7] for deterministic case, and Błaszczyk et al. in [3] for fuzzy estimations. Models supporting the decision-maker in the role of general contractor was described by Błaszczyk and Błaszczyk in [8] for the most general case and in [4] for specific expression of fixed price and cost-plus contracts and more broadly in [5]. ...
In this paper we describe partial results of the research focused on the improvement of the decision-making quality and control in the project contracts management in concurrent environment. Bearing in mind the diversity of interdependences between the stakeholders involved in the project and their decisions, our considerations are embedded in the complex systemic process model introduced by one of the most popular project management methodologies. Here we propose the improved process of project contractors selection associated with the contract type selection and work distribution. The model of this process is developed with the ability to use in the environment with multiple contractors and their sub- contractors on the one of more levels.
... Classical scheduling methods of CPM (Critical Path Method) and PERT (Program Evaluation and Review Technique) do not explicitly take into account the factors associated with the uncertainty that surrounds the choice of the contractor and his participation in the implementation of the project scope. Therefore, in the later part of the paper we Manuscript use assumptions described by Błaszczyk et al. [3] in terms of the bi-criterial model of project with time and cost buffers designed based on the concept of CCPM (Critical Chain Project Management). Concept of Critical Chain (Goldratt [4]) is one of the Newest project management methodologies. ...
Depending on your view of the allocation of risk between the project owner and contractor use are two main types of contracts. In this paper, we analyze the problem of optimal selection of sub-contractors in the case of the application of a fixed price and a cost-plus contracts. Models described in the article can be found applicable in the relations between the project owner and the contractor and between the contractor and sub-contractors. As a methodological basis we use the multi-criterial decision model assigning each task to specific contractors (or subcontractors) in the project with the function of distribution of penalties arising from delayed completion and potential benefits in the event of early termination of the project.
This paper is a summary of work on the construction of the optimization model for decision-makers implementing projects in which the issue is the involvement of external contractors. Using the results of our current works on optimization approaches to the problem of contractors selection with the use of incentive mechanisms, we propose an outline of a comprehensive decision support system (DSS). The practical aim is to enable support for both project owners and contractors in the decision of any sub-contractors at the lower levels of the Work Breakdown Structure (WBS).
The aim of this paper is to show how to minimize the project costs by using fuzzy quantities and schedule buffers. Very often, companies make rigid schedules that do not allow changes to be made. In this article we propose utilization of buffers to create soft schedules that can allow the easy application of changes during the project.
Depending on your view of the allocation of risk between the project owner and contractor use are three main types of contracts. In this paper, we analyze the problem optimal selection of subcontractors in the case of the application a fixed price, cost-plus and time and materials contracts. Models described in the article can be found applicable in the relations between the project owner and the contractor and between the contractor and subcontractors. As a methodological basis we use the multi-criterial decision model assigning each task to specific contractors (subcontractors) in the project with the function of distribution of penalties arising from delayed completion and potential benefits in the event of early project termination.
The aim of this research was the trial of modelling and optimizing the time-cost trade-offs in project planning problem with taking into account the behavioral impact of performers’ (or subcontractors’) estimations of basic activity parameters. However, such a model must include quantitative measurements of budget and duration, so we proposed to quantify and minimize the apprehension of their underestimations. The base of the problem description contains both safe and reasonable amounts of work estimations and the influence factors matrix. We assumed also the pricing opportunity of performance improving. Finally we introduce fuzzy measurements for work amount. This paper is a revised, extended version of Blaszczyk et al. 2011, presented on the World Congress on Engineering and Computer Science 2011.
Most of today's projects are interdisciplinary and requires the involvement of contractors that specialize in different types of works. In various circumstances, it may be advisable to minimize their multiplicity or their diversification. In some cases it may be desirable to meet certain characteristics by contractors for selected tasks. The aim of this paper is to determine the model of selection of contractors in complex project from the point of view of the project owner or general contractor. As a methodological basis we use the multi-criterial decision model assigning each task to specific contractors in the project with the function of distribution of penalties arising from delayed completion and potential benefits in the event of early termination of the project.
This research focus on the problem of modeling and optimizing the time-cost trade-offs in project planning problem with taking into account the behavioral impact of planned human resources. As a distinct from the original Goldratt conception and heretofore research results and known applications we proposed an approach taking advantage not only from task duration overestimations, but primarily from overestimations of amounts of work expected to its completion. Proposed problem description contains both safe and reasonable amounts of work estimations. At the recent stage of research we introduced the influence factors matrix with the possibility of flexible resources assignment. The model uses a mechanism of motivating the resources through the creation of bonus fund from the pool of savings. Theoretical considerations are illustrated by the numerical example.
The aim of this research was the trial of modelling and optimizing the time-cost trade-offs in project planning problem with taking into account the behavioral impact of performers' (or subcontractors') estimations of basic activity parameters. However, such a model must include quantitative measurements of budget and duration, so we proposed to quan-tify and minimize the apprehension of their underestimations. The base of the problem description contains both safe and reasonable amounts of work estimations and the influence factors matrix. We assumed also the pricing opportunity of performance improving. Finally we introduce fuzzy measure-ments for work amount.
