A survey of variants and extensions of the resource-constrained project scheduling problem <s> Project Selection and Scheduling <s> This paper deals with the lead optimization phase of pharmaceutical research where a number of leads (molecules as a basis for potential drugs) are processed by different departments in order to optimize their biochemical characteristics. We depict each lead as a project and model the problem as a static multi-project selection and scheduling problem under resource constraints with the objective to maximize the weighted work performed. For solving the problem we propose two heuristics. We assess their performance in a computational study and we point out one dominant method. Furthermore we show the impact of problem parameters such as the extend to which projects can be crashed. <s> BIB001 </s> A survey of variants and extensions of the resource-constrained project scheduling problem <s> Project Selection and Scheduling <s> In this paper we formulate and analyze the joint problem of project selection and task scheduling. We study the situation where a manager has many alternative projects to pursue such as developing new product platforms or technologies, incremental product upgrades, or continuing education of human resources. Project return is assumed to be a known function of project completion time. Resources are limited and renewable. The objective is to maximize present worth of profit. A general mathematical formulation that can address several versions of the problem is presented. An implicit enumeration procedure is then developed and tested to provide good solutions based on project ordering and a prioritization rule for resource allocation. The algorithm uses an imbedded module for solving the resource-constrained project scheduling problem at each stage. The importance of integrating the impact of resource constraints into the selection of projects is demonstrated. <s> BIB002
Chen and Askin BIB002 develop a multi-project problem which contains two types of decisions: First, a set of candidate projects is given, and the projects to be carried out are selected (this allows to decide, e.g., which product development projects should be executed). Second, the selected projects are scheduled subject to the usual precedence and renewable resource constraints. The project selection and scheduling decisions are made simultaneously with the objective to maximize the net present value. Kolisch and Meyer BIB001 integrate project selection and scheduling into a problem for pharmaceutical research projects. The selection of projects is captured by modes reflecting that an activity is not executed, while the mode identity concept ensures that either all activities of a project are carried out or none. The problem further includes time-dependent resource requests and an objective that is based on the net present value.