6 research outputs found
Locating a semi-obnoxious facility in the special case of Manhattan distances
The aim of thiswork is to locate a semi-obnoxious facility, i.e. tominimize the distances
to a given set of customers in order to save transportation costs on the one hand and to
avoid undesirable interactions with other facilities within the region by maximizing
the distances to the corresponding facilities on the other hand. Hence, the goal is to
satisfy economic and environmental issues simultaneously. Due to the contradicting
character of these goals, we obtain a non-convex objective function. We assume that
distances can be measured by rectilinear distances and exploit the structure of this
norm to obtain a very efficient dual pair of algorithms
Locating waste pipelines to minimize their impact on marine environment
A waste pipeline, considered as an undesirable facility, is to be located in a coastal region. Two criteria are taken into
account, the Euclidean distance from a given set of protected areas (coral reefs and sandbanks) and a utility function related
to the pipe length, both to be maximized. The paper describes a methodology to obtain an efficient set of points where the
extreme of a marine pipeline should be located. Since the formulation of the model is based on the zone Voronoi diagram,
the computational complexity of the solving procedure is low
On multimodality of obnoxious faclity location models
Obnoxious single facility location models are models that have the aim to find the best location
for an undesired facility. Undesired is usually expressed in relation to the so-called demand
points that represent locations hindered by the facility. Because obnoxious facility location
models as a rule are multimodal, the standard techniques of convex analysis used for locating
desirable facilities in the plane may be trapped in local optima instead of the desired global
optimum. It is assumed that having more optima coincides with being harder to solve. In this
thesis the multimodality of obnoxious single facility location models is investigated in order to know which models are challenging problems in facility location problems and which are
suitable for site selection. Selected for this are the obnoxious facility models that appear to be most important in literature. These are the maximin model, that maximizes the minimum
distance from demand point to the obnoxious facility, the maxisum model, that maximizes the
sum of distance from the demand points to the facility and the minisum model, that minimizes
the sum of damage of the facility to the demand points. All models are measured with the
Euclidean distances and some models also with the rectilinear distance metric. Furthermore a
suitable algorithm is selected for testing multimodality. Of the tested algorithms in this thesis, Multistart is most appropriate. A small numerical experiment shows that Maximin models have on average the most optima, of which the model locating an obnoxious linesegment has the
most. Maximin models have few optima and are thus not very hard to solve. From the Minisum
models, the models that have the most optima are models that take wind into account. In general can be said that the generic models have less optima than the weighted versions. Models that are measured with the rectilinear norm do have more solutions than the same models measured with the Euclidean norm. This can be explained for the maximin models in the numerical example because the shape of the norm coincides with a bound of the feasible area, so not all solutions are different optima. The difference found in number of optima of the Maxisum and Minisum can not be explained by this phenomenon
Hazardous waste management problem: The case for incineration
We define the hazardous waste management problem as the combined decisions of selecting the disposal method, siting the disposal plants and deciding on the waste flow structure. The hazardous waste management problem has additional requirements depending on the selected disposal method. In this paper we focus on incineration, for which the main additional requirement is to satisfy the air pollution standards imposed by the governmental restrictions. We propose a cost-based mathematical model in which the satisfaction of air pollution standards is also incorporated. We used the Gaussian Plume equation in measuring the air pollution concentrations at population centers. A large-scale implementation of the proposed model within Turkey is provided. © 2005 Elsevier Ltd. All rights reserved
A unified model for hazardous waste management problem : application in Turkey
Cataloged from PDF version of article.In real life a number of institutions, typically with conflicting objectives, are
affected from the hazardous waste management problem. We investigate all
related issues in the hazardous waste management from each institution’s
perspective. We define the hazardous waste management problem as the
combined decisions of selecting the disposal method, siting the selected
disposal plant, deciding on the waste flow structure and satisfying any other
criteria required by any of the interested institutions. We develop a new
unified mathematical model. In order to satisfy law and legislation
requirements the incorporation of the Gaussian plume model into our unified
model is also accomplished. A large scale implementation into regions of
Turkey is provided.Emek, EvrenM.S