GCRIS

Now showing 1 - 4 of 4

Minisum and maximin aerial surveillance over disjoint rectangles
(2016) Karasakal, Orhan
The aerial surveillance problem (ASP) is finding the shortest path for an aerial surveillance platform that has to visit each rectangular area once and conduct a search in strips to cover the area at an acceptable level of efficiency and turn back to the base from which it starts. In this study, we propose a new formulation for ASP with salient features. The proposed formulation that is based on the travelling salesman problem enables more efficient use of search platforms and solutions to realistic problems in reasonable time. We also present a max–min version of ASP that maximizes the minimum probability of target detection given the maximum flight distance of an aerial platform. We provide computational results that demonstrate features of the proposed models.
Citation - Scopus: 23
Using Announcement Options in the Bid Construction Phase for Disaster Relief Procurement
(2012) Ertem, M.A.; Buyurgan, N.; Pohl, E.A.
This paper presents an analysis of the bid construction phase of procurement auctions in disaster relief and humanitarian logistics. Substitution and partial fulfillment options are presented in formulations to allow bidders with fewer inventories to offer substitute item types and partial bids in auctions. During the auction announcement phase, a coordinating platform for disaster locations (i.e., auctioneer) allows substitution and partial fulfillment options to the relief suppliers (i.e., bidders) when acceptable. Thus, suppliers with fewer inventories can offer substitute item types and participate in more auctions by partially bidding. A genetic algorithm, a simulated annealing algorithm and an integer program are used for the analysis of the bid construction phase with different announcement options. Heuristic solution techniques and an IP formulation help understand the dynamics of the bid construction problem. It is shown that the addition of substitution and partial fulfillment options is essential to diversify and increase the usable capacity of the supplier base. Additionally, the partial fulfillment option enables better usage of supplier inventories in an environment with scarce supplies. © 2012 Elsevier Ltd.
Citation - WoS: 30
Citation - Scopus: 34
An Auction-Based Framework for Resource Allocation in Disaster Relief
(Emerald Group Publishing Ltd, 2011) Buyurgan, Nebil; Ertem, Mustafa Alp; Alp Ertem, Mustafa
Purpose - The purpose of this paper is to address the inefficiency problems in procurement operations in disaster relief logistics which are mainly due to the lack of coordination among less organized suppliers and partnerships. Such problems lead to poor responsiveness and hinder timely procurement of required goods. Design/methodology/approach - An auction-based framework for procurement of goods, which is suitable for a single coordinating platform in disaster relief logistics, is proposed. Integer programming formulations are used in auctioning operations. A simulation model that generates problem instances is used to evaluate and tune system-level design parameters. Findings - Design parameters greatly affect the behaviour and responsiveness of the system and the performance of the auction-based framework in different problem instances. Combinations of those parameters may allow suppliers with limited capacities to become more involved in the bidding process. In addition, the procurement shares of bidders may change substantially with different values of the parameters. Research limitations/implications - Even though the presented framework is inspired from reallife applications, it is not implemented in real-life disaster relief operations. The goodness of fit for the framework would best be evaluated by a real disaster case. In addition, transportation scheduling and vehicle routing considerations and budgeting issues are not considered in the framework. Originality/value - This paper presents an auction-based framework for less organized suppliers of goods and their partnerships, such as local humanitarian organizations, private companies, and standby partners. The presented framework offers a background for coordination during disaster relief operations which provides opportunities to act as a set of organized entities. This background also helps those entities coordinate their efforts to enhance the capabilities of local governments and NGOs.
Citation - WoS: 5
Citation - Scopus: 8
Lp Relaxation-Based Solution Algorithms for the Multi-Mode Project Scheduling With a Non-Renewable Resource
(inderscience Enterprises Ltd, 2015) Cetinkaya, Ferda Can; Pamir, Selin Kirbiyik; Azizoglu, Meral
In this study, we consider a multi-mode resource allocation problem with a single non-renewable resource. We assume the resource is released at defined time points and at defined quantities. We also assume that the activity costs are charged once they are completed. Our aim is to minimise the project completion time. We formulate the problem as a pure integer programming model and show that it is strongly NP-hard. We find lower bounds by pure and mixed integer linear programming relaxations of the model and develop three heuristic procedures based on those relaxations. The results of our computational study have revealed the satisfactory performances of our lower bounds and heuristic procedures.

Endüstri Mühendisliği Bölümü Yayın Koleksiyonu

Browse

Filters

Settings

Sort By

Results per page

Search Results