An Integer Linear Programming Model for Project Portfolio Selection in a Community

Author(s):  
C.O. Anyaeche ◽  
R.A. Okwara

Project portfolio selection involves decision making and it plays a crucial role in any organization. Therefore selecting not just the right projects but also the right mix of projects for the portfolio is considered as one of the most important tasks for organisations to ensure the achievement of the corporate strategy within limited resources and capabilities of the organization. Prioritizing and selecting optimal project portfolio can be very challenging especially with a large number of projects with multiple constraints and interdependences. In an ideal world with unlimited budget the project selection process would be very straightforward. However, this is not the case in life situations. In this work, an attempt is made to address this challenge. An integer linear programming model for project selection was developed and applied in a selected organization in Nigeria. The model seeks to optimize the mix of the projects to be undertaken while keeping the total cost and project interdependency as constraints. The analysis of the results showed that a total of 11 projects out of 16 were eligible for selection in the period under review. The total cost of the selected project was 92,840,000 Naira, which was about 90% of the total budget. Ordinarily, apart from not prioritizing and obtaining an optimal project mix, the community would have spread its entire resources on the 16 projects with some of them being abandoned later. The model can also be used to plan an optimal mix of project portfolio for a future date within the limitations of a given set of constraints and interdependence.

Author(s):  
Feng Wang ◽  
Zhanmin Zhang ◽  
Randy B. Machemehl

A typical pavement management system (PMS) should help a decision maker select the best maintenance program—that is, which maintenance treatment to use and where and when to apply it—so that maximal use is made of available resources. To provide decision support, a PMS needs a process for setting maintenance and rehabilitation (M&R) priorities. The quality of the prioritization directly influences the effectiveness of available resources, which in most cases is the primary goal of the decision maker. A network-level project selection procedure that uses an operations research optimization method was developed. An integer linear programming model was established to select a set of candidate projects from the highway network over a planning horizon of 5 years. In the model, constraints of available annual budgets and minimum requirements on pavement conditions were satisfied where state transition of each road section was formulated. Two optimization objectives—maximization of the total M&R effectiveness and minimization of the total M&R disturbance cost— were pursued over the planning horizon. A small network of 10 road sections was used as a pilot study for the established model. Pavement management functionalities at the network level are summarized, formulation of the integer linear programming model for the project selection problem is presented, differences in decision makers' value systems and the resulting different undominated solutions are discussed, and a sensitivity analysis of the annual budget constraint is conducted.


2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
YuFeng Chen ◽  
Abdulrahman Al-Ahmari ◽  
Chi Tin Hon ◽  
NaiQi Wu

This paper focuses on the enforcement of nonlinear constraints in Petri nets. An integer linear programming model is formulated to transform a nonlinear constraint to a minimal number of conjunctive linear constraints that have the same admissible marking space as the nonlinear one does in Petri nets. The obtained linear constraints can be easily enforced to be satisfied by a set of control places with a place invariant based method. The control places make up a supervisor that can enforce the given nonlinear constraint. For a case that the admissible marking space decided by a nonlinear constraint is nonconvex, another integer linear programming model is developed to obtain a minimal number of constraints whose disjunctions are equivalent to the nonlinear constraint with respect to the reachable markings. Finally, a number of examples are provided to demonstrate the proposed approach.


Sign in / Sign up

Export Citation Format

Share Document