دانلود رایگان مقاله انگلیسی توسعه مدل سازی شبکه توسعه محصول برای روش حذف چرخه - الزویر 2018

ABSTRACT

This paper considers Product Development (PD) project networks, which are characterized by stochastic activity durations and activity rework or iteration (i.e., potential to repeat some activities several times during PD execution). The Cycle Elimination (CE) approach presented in Nasr et al. (2016) reduces the computational complexity of analyzing iterative PD project networks by considering an approximate network with no iteration. We build on the CE approach to investigate practical scenarios which arise in real world PD projects which are not accounted for by the CE approach. These scenarios include: (i) forward probabilities, (ii) dynamic rework probabilities and proportions, (iii) multiple dependency relationships between activities, and (iv) different rework through indirect connections. We demonstrate these extensions using two case studies. The first case study considers a software development process, where we collected the data by interviewing the managers of the company. The second case study involves a hardware development process (adapted from Pinkett (1998)), where the results show that the proposed method outperformed three existing techniques from the literature. Both cases were solved using the proposed modification to the CE approach, and then simulated to gauge the accuracy of the proposed method showing very promising results.

5 Summary, discussion and conclusion

Finding a good estimate of the expected duration (and cost) to develop complex products can be crucial for project managers as they plan for resources and provide clients with estimated completion times. Poor resource planning, staffing decisions, and commitments can result from inaccurate estimates of project duration. Additionally, contractual penalties may arise for noncompliance with promised delivery times. Simulation models to find the expected project duration can be time consuming to design, build, and run. Thus, our focus in this paper is on analytical techniques which can generate the results more promptly.

The cycle elimination (CE) method (Nasr et al., 2016) is an analytical technique which can be used to solve sequential and mixed networks (combination of sequential and parallel activities). The method tackles PD networks having feedback possibilities by transforming the network to a non-cyclic network in order to proceed with traditional project management techniques to find the expected duration. The method uses DSM to represent the network and finds the stage expected durations based on the DSM inputs, where the stages represent the activity's expected duration and their possible rework. Modifications to DSM are necessary for the method capture different complications. Two special cases, coupled activities and allowing parallel rework, were discussed by Nasr et al. (2016) and in this paper we extended the method to account for four additional complications (i) forward probabilities, (ii) dynamic rework probabilities and proportions, (iii) multiple dependency relationships between activities, and (iv) different rework through indirect connections.