- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
Time Cost Trade-off Problems have received considerable attention in the literature on deterministic project scheduling problems but integrating the quality factor to these problems dates back to the mid-nineties with the pioneering work of Babu and Suresh (1996). Since then, to the best of our knowledge, about twenty papers have been published on this topic. The present paper analyses these Time Cost Quality Trade-off Problems in light of the usual classification for Time Cost Trade-off Problems that is based upon the number and category of resources and on the continuous or discrete type of the relationship between duration and cost or resources utilisation. In this survey, the emphasis is on the definition of project activities quality and on aggregation methods used to derive the overall project quality. We report the absence of a direct relationship between quality and resources allocated to activities and a lack of use of the lexicographic method to solve the problem.
7. Summary and conclusions
Based upon the previous literature review, we draw the following summary and conclusions.
• Resources. The vast majority of Time Cost Quality Trade-off Problems studied here consider a single non renewable resource in a continuous framework (CTCTP and Quality) or in a discrete one (DTCTP and Quality). One paper deals with RCSP and rework where quality is not explicitly taken into account (Icmeli-Tukel and Rom, 1997) and two contributions tackle MRCPSP where quality is explicitly considered with possible rework (Fu and Zhang, 2016) and without rework (Afruzi et al. 2014). Quality factor is never introduced in DTRTP or MDTRTP so the quality is never modelled as a function of resources.
• Activity quality. When not estimated in each execution mode, activity quality is assumed to be a continuous function of duration only or duration and cost. Quality is a linear increasing function of duration in Babu and Suresh (1996) and Khang and Myint (1999). Quality is a quadratic function of duration in Zhang et al. (2014) and Tran et al. (2015). Quality is expressed as a non linear function of duration and cost in Liberatore and Pollack-Johnson (2013) and in Fu and Zhang (2016). Let us note that quality of an activity has never been formulated directly as a function of resources such as manpower. Rather, quality depends on cost which depends itself on resources. However it has been shown that quality degrades when additional manpower is used for acceleration due to overmanning and overtime (see Li et al., 2000). It would therefore be possible to formulate such a direct relationship between quality and manpower to model a DTRTP with quality.