The budget constrained discrete time/cost trade-off problem in project networks

Download
2008
Değirmenci, Güvenç
The time/cost trade-off models in project management aim to compress the project completion time by accelerating the activity durations at an expense of additional resources. The budget problem in discrete time/cost trade-off scheduling selects the time/cost mode -among the discrete set of specified modes- for each activity so as to minimize the project completion time without exceeding the available budget. There may be alternative modes that solve the budget problem optimally, however each solution may have a different total cost value. In this study we aim to find the minimum cost solution among the optimal solutions of the budget problem. We analyze the structure of the problem together with its linear programming relaxation and derive some mechanisms for reducing the problem size. We solve the reduced problem by linear programming relaxation and branch and bound based approximation and optimization algorithms. We find that our branch and bound algorithm finds optimal solutions for medium-sized problem instances in reasonable times and the approximation algorithms produce high quality solutions. We also discuss the way our algorithms could be used to construct the time/cost trade-off curve.

Suggestions

A lagrangean heuristic for the two-stage modular capacitated facility location problem
Sevinç, Selim; Meral, Fatma Sedef; Department of Industrial Engineering (2008)
In this study, a Lagrangean heuristic based on Lagrangean relaxation and subgradient optimization is proposed for the two-stage modular capacitated facility location problem. The objective is to minimize the cost of locating and operating plants and warehouses, plus the cost of transporting goods at both echelons to satisfy the demand of customers. The difference of our study from the two-stage capacitated facility location problem is the existence of multiple capacity levels as a candidate for each plant i...
On the service models for dynamic scheduling of multi-class base-stock controlled systems
Kat, Bora; Avşar, Zeynep Müge; Department of Industrial Engineering (2005)
This study is on the service models for dynamic scheduling of multi-class make-to-stock systems. An exponential single-server facility processes different types of items one by one and demand arrivals for different item types occur according to independent Poisson processes. Inventories of the items are managed by base-stock policies and backordering is allowed. The objective is to minimize base-stock investments or average inventory holding costs subject to a constraint on the aggregate fill rate, which is...
On construction of stable project schedules
Görmez, Baran; Serpil, Canan; Department of Industrial Engineering (2005)
It is a well-known fact that project activities are subject to considerable uncertainty, which may lead to multiple schedule disruptions during project execution. As a result, the random nature of activity durations has been the subject of numerous research efforts since the introduction of the initial PERT. A common problem which arises in project management is the fact that the planned schedule is often disrupted by several uncontrollable factors like weather conditions, other environmental factors, addit...
Disassembly line balancing problem with fixed number of workstations and finite supply
Göksoy, Eda; Azizoğlu, Meral; Department of Industrial Engineering (2010)
In this thesis, we consider a Disassembly Line Balancing Problem (DLBP) with fixed number of workstations. We aim to maximize the total value of the recovered parts. We assume that there is a limited supply for the products to be disassembled. Different components can be obtained by disassembling different units of the product. Our aim is to assign the tasks to the workstations of the disassembly line so as to maximize the total value of the recovered parts. We present several upper and one lower bounding p...
The inventory routing problem with deterministic order-up-to level inventory policies
Pınar, Özlem; Süral, Haldun; Department of Industrial Engineering (2005)
This study is concerned with the inventory routing problem with deterministic, dynamic demand and order-up-to level inventory policy. The problem mainly arises in the supply chain management context. It incorporates simultaneous decision making on inventory management and vehicle routing with the purpose of gaining advantage from coordinated decisions. An integrated mathematical model that represents the features of the problem is presented. Due to the magnitude of the model, lagrangean relaxation solution ...
Citation Formats
G. Değirmenci, “The budget constrained discrete time/cost trade-off problem in project networks,” M.S. - Master of Science, Middle East Technical University, 2008.