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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Multi-Actor Multi-Criteria Decision Analysis  of EU Policies for First Generation Biofuels

Martinov, Sonja January 2015 (has links)
In this paper multi-actor multi-criteria decision aid methodology are developed to examine the impacts of EU policies related to first generation biofuels on identified key stakeholders. The thesis focuses on the integration of relevant qualitative and quantitative criteria defined by key stakeholders into one comprehensive evaluation process, to serve as a decision support tool for decision makers. Weight allocation of the defined criteria will be assessed by using the Analytic Hierarchy Process (AHP) framework, where the multi-criteria decision-aid method PROMETHEE II is used to rank relevant policy alternatives based on the information provided. In the end, results will help the decision makers to identify the impacts of different EU policy alternatives on each stakeholder group.
212

A simulation-based multi-criteria management system for optimal water supply under uncertainty

Tinh, Pham Van 22 June 2015 (has links) (PDF)
For cost and reliability efficiency, optimal design and operation of pressurized water distribution networks is highly important. However, optimizing such networks is still a challenge since it requires an appropriate determination of: (1) dimension of pipe / pump / tank - decision variables (2) cost / network reliability - objective functions and (3) limits or restrictions within which the network must operate - a given set of constraints. The costs mentioned here consist in general of capital, construction, and operation costs. The reliability of a network mainly refers to the intrinsic capability of providing water with adequate volume and a certain pressure to consumers under normal and extreme conditions. These contradicting objective functions are functions of network configuration regarding component sizes and network layout. Because considerable uncertainties finally render the overall task to a highly complex problem, most recent approaches mainly focus only on finding a trade-off between minimizing cost and maximizing network reliability. To overcome these limitations, a novel model system that simultaneously considers network configuration, its operation and the relevant uncertainties is proposed in this study. For solving this multi-objective design problem, a simulation-based optimization approach has been developed and applied. The approach couples a hydraulic model (Epanet) with the covariance matrix adaptation evolution strategy (CMA-ES) and can be operated in two different modes. These modes are (1) simulation–based Single-objective optimization and (2) simulation-based multi-objective optimization. Single-objective optimization yields the single best solution with respect to cost or network reliability, whereas multi-objective optimization produces a set of non-dominated solutions called Pareto optimal solutions which are trade-offs between cost and reliability. In addition, to prevent a seriously under-designed network, demand uncertainties was also taken into account through a so called “robustness probability” of the network. This consideration may become useful for a more reliable water distribution network. In order to verify the performance of the proposed approach, it was systematically tested on a number of different benchmark water distribution networks ranging from simple to complex. These benchmark networks are either gravity-fed or pumped networks which need to be optimally designed to supply urban or irrigation water demand under specific constraints. The results show that the new approach is able: • to solve optimization problems of pressurized water distribution network design and operation regarding cost and network reliability; • to directly determine the pumping discharge and head, thus allowing to select pumps more adequately; • to simulate time series of tank water level; • to eliminate redundant pipes and pumps to generate an optimal network layout; • to respond well to complex networks other than only to simple networks; • to perform with multiple demand loading; • to produce reliable Pareto optimal solutions regarding multi-objective optimization. In conclusion, the new technique can be successfully applied for optimization problems in pressurized water distribution network design and operation. The new approach has been demonstrated to be a powerful tool for optimal network design not only for irrigation but also for an urban water supply.
213

Determining the best location for a nature-like fishway in Gavle River, Sweden

Buck, Sine January 2013 (has links)
The construction of dams and hydro-power stations are some of the most common anthropogenic changes of watercourses and rivers. While being important to humans and society by providing electricity, these obstructions of watercourses can have severe consequences for the aquatic ecosystems. One consequence is that dams often hinder the important movement of migrating fish species between habitats. This can lead to decline and even extinction of important fish populations. To prevent these negative effects, a number of different fish passage systems, including nature-like fishways, have been developed. Nature-like fishways mimic natural streams in order to function as a natural corridor for a wide range of species. Planning and construction of a nature-like fishway is a complex task that often involves many different interests. In the present study a combination of multi-criteria decision analysis and least-cost path analysis is used for determining the best location for a nature-like fishway past Strömdalen dam in Gavleån, Sweden. An anisotropic least-cost path algorithm is applied on a friction-layer and a digital elevation model, and the least-cost path for a nature-like fishway is determined. The results show that the method is useful in areas of varying topography and steep slopes. However, because low slope is a very important factor when constructing a nature-like fishway, slope becomes the dominating factor in this analysis at the expense of e.g. distance to roads. Combining the methods with results from biological studies of fish behavior and detailed hydrological modelling would provide a very strong tool for the planning of nature-like fishways.
214

An AHP framework for balancing efficiency and equity in the United States liver transplantation system

Veerachandran, Vijayachandran M 01 January 2006 (has links)
ABSRACT: Liver transplantation and allocation has been a controversial issue in the United States for decades. One of the main concerns in the allocation system is the trade-off between the two main objectives, efficiency and equity. Unfortunately, it is difficult to reach consensus on how to develop allocation policies that aim at balancing efficiency and equity, among transplantation policy makers, administrators, transplant surgeons and transplant candidates.Our research identifies and classifies the outcomes of liver allocation into two major categories, efficiency and equity, that are, often times, conflicting. Previous researchers did not consider how to balance outcomes in these two categories. Our research uses Analytic Hierarchy Process, a Multi-Criteria Decision Analysis methodology, to build a framework that quantifies the decision-making process and help decision makers to reach a valid consensus in terms of balancing these outcomes. Latest available patient registration and follow-up data are used in data analysis. Results from this analysis serve as inputs for the simulation model that is capable of evaluating alternative hypothetical policies.This research addresses the deficiencies of the current liver transplantation policy and is intended to refine the policy that will result in a more balanced allocation system with respect to efficiency and equity. Our proposed methodology can be applied to incorporate further changes in policy selection and refinement.
215

Πολυκριτηριακή ανάλυση και χωροθέτηση τραπεζικών καταστημάτων

Παπλά, Νεκταρία-Κονδύλω 18 June 2009 (has links)
Σχεδόν κάθε επιχείρηση ιδιωτικού και δημόσιου τομέα την οποία μπορούμε να σκεφτούμε, έχει βρεθεί αντιμέτωπη με το πρόβλημα της χωροθέτησης των εγκαταστάσεών της κάποια στιγμή στην ιστορία της. Αυτό έχει οδηγήσει σε ένα έντονο ενδιαφέρον για την ανάλυση χωροθέτησης στα πλαίσια της επιχειρησιακής έρευνας. Η εγκατάσταση ενός νέου τραπεζικού υποκαταστήματος που αποτελεί ένα σημαντικό μέρος του προγραμματισμού και της διαχείρισης δικτύων κλάδων. απαιτεί μία πολύπλοκη διαδικασία λήψης απόφασης. Η λήψης της απόφασης αυτής μπορεί να ωφεληθεί από τη χρήση της πολυκριτηριακής ανάλυσης αποφάσεων (MCDM) καθιστώντας τη διαδικασία πιο ορθολογική και αποδοτική. Στην παρούσα εργασία εξετάζουμε το πρόβλημα της χωροθέτησης ενός τραπεζικού καταστήματος στα πλαίσια της πολυκριτηριακής ανάλυσης αποφάσεων (MCDM). / Almost every private and public sector enterprise that we can think of, has been faced with the problem of locating facilities at one time or another of its history. Τhis has led to a strong interest in location analysis within the operations research and management science community. Locating a new bank branch, an important part of branch network planning and management is a complex decision making progress. This decision making progress can benefit from the use of Multi-Criteria Decision Making (MCDM) progress by making the progress more explicit, rational and efficient. In the present work we examine the problem of locating a bank branch using MCDM.
216

Ελάχιστα γεννητικά δένδρα με πολλαπλά κριτήρια / Multi-criteria minimum spanning trees

Σταθοπούλου, Ευθυμία 16 May 2007 (has links)
Η εύρεση γεννητικών δέντρων ελάχιστου-κόστους αποτελεί ένα κλασικό επιστημονικό πρόβλημα με σημαντικές εφαρμογές στη σχεδίαση δικτύων. Δοθέντος ενός γραφήματος, όπου κάθε πλευρά σχετίζεται με ένα βάρος (κριτήριο) το πρόβλημα της εύρεσης ενός Ελάχιστου Γεννητικού Δέντρου ανέρχεται στο πρόβλημα της εύρεσης ενός γεννητικού δέντρου με το ελάχιστο συνολικό κόστος. Το πρόβλημα ΕΓΔ έχει αποτελέσει αντικείμενο ενδιαφέροντος πολλών μελετητών με αποτέλεσμα την ανάπτυξη αλγορίθμων πολυωνυμικού-χρόνου, όπως είναι ο αλγόριθμος του Prim, του Sollin και του Kruskal. Στον πραγματικό κόσμο όμως υπάρχουν περιπτώσεις όπου πρέπει να λάβουμε ταυτόχρονα υπόψη πολλά κριτήρια προκειμένου να καθορίσουμε ένα ΕΓΔ. Αυτό συμβαίνει γιατί κάθε πλευρά του γραφήματος σχετίζεται με παραπάνω από ένα κόστη. Για παράδειγμα, στη σχεδίαση ενός τηλεπικοινωνιακού δικτύου, πέρα από το κόστος κατασκευής των συνδέσεων μεταξύ των πόλεων ή των τερματικών μας ενδιαφέρουν και άλλοι παράγοντες. Ο χρόνος που απαιτείται για την κατασκευή, η δυσκολία και πολυπλοκότητα της κατασκευής, η καθυστέρηση μετάδοσης της πληροφορίας αλλά και η αξιοπιστία του συστήματος αποτελούν σημαντικούς παράγοντες που πρέπει να ληφθούν υπόψη στην σχεδίαση του δικτύου. Αλλά και στην καθημερινή ζωή, πολλές φορές χρειάζεται να ληφθούν σημαντικές αποφάσεις οι οποίες εξαρτώνται από περισσότερα από ένα κριτήρια. Παραδείγματος χάριν, άνθρωποι που ταξιδεύουν θέλουν να βελτιστοποιήσουν τη διανυόμενη απόσταση, το κόστος, και το χρόνο μετακίνησης. Το ζητούμενο είναι πως μπορεί να οδηγηθεί κανείς στη λήψη μιας βέλτιστης για αυτόν απόφασης, που κάτω από δεδομένες συνθήκες μπορεί να είναι περισσότερες από μία. Δηλαδή, δεν οδηγούμαστε σε μία μοναδική βέλτιστη λύση αλλά σε ένα σύνολο από «βέλτιστες» λύσεις και ο ενδιαφερόμενος, ανάλογα με τα ιδιαίτερα χαρακτηριστικά του προβλήματος, κάνει την τελική επιλογή. Το πρόβλημα ΕΓΔ, στο οποίο ζητείται η ελαχιστοποίηση περισσοτέρων του ενός κριτηρίων είναι γνωστό ως το πρόβλημα ΕΓΔ πολλαπλών κριτηρίων (multi-criteria minimum spanning tree problem). Η συνεισφορά της παρούσας διπλωματικής λοιπόν αποτελείται από δύο μέρη: Το πρώτο, εστιάζεται στην κριτική επισκόπηση και περιγραφή των υπαρχόντων μεθόδων επίλυσης του προβλήματος ΕΓΔ δύο κριτηρίων. Το δεύτερο, αφορά την υλοποίηση και πειραματική αξιολόγηση δύο βασικών αλγορίθμων για την επίλυση του εν λόγω προβλήματος. Συγκεκριμένα, υλοποιήθηκε η τροποποιημένη εκδοχή (για το πρόβλημα ΕΓΔ πολλαπλών κριτηρίων) του αλγορίθμου του Prim καθώς και μία προσεγγιστική μέθοδος επίλυσης του προβλήματος ΕΓΔ πολλαπλών κριτηρίων. / The minimum spanning tree problem (MST) is of high importance in network optimization. Given a connected graph G where each edge has a weight, the goal is to find the spanning tree with the least cost among all spanning trees of G. Due to its many practical applications, the MST problem has been studied in depth and many efficient polynomial-time algorithms have been developed by Sollin, Kruskal, Prim etc. But in real life, there cases where one has to take simultaneously into consideration many criteria in order to determine a MST because there are multiple weights defined on each edge of the graph. For example, when designing the layout of a telecommunication network, besides the cost for connections between cities or terminals we are interested in other factors too. The time for communication and construction, the difficulty of the construction or the reliability of the system are also important factors and need to be taken into consideration. But also in everyday life, in many cases we need to take decisions that depend on multiple criteria. For instance, people who travel want to minimize simultaneously the cost, the distance and the time. The problem is that in these cases there is not only one optimal solution but rather a set of optimal solutions and the decision maker depending on the characteristics of each case will make the final call. The MST problem in which we want to minimize more than one criteria is known as the multi-criteria minimum spanning tree problem. The contribution of this thesis is composed of two parts. The first part focuses on the critical survey and description of various methods for solving the bi-criteria case of the MST problem. The other part focuses on the implementation and the experimental evaluation of two known and important algorithms. More precisely, we have implemented the modified version of the Prim’s algorithm (for the multi-criteria MST problem) and one approximate algorithm as proposed by Hamacher & Ruhe.
217

Participatory multi-criteria assessment for monitoring actions and supporting decision making to combat desertification in the San Simon watershed (Arizona)

Ocampo-Melgar, Anahi January 2013 (has links)
Assessment of the myriad of historic attempts to manage and/or restore degraded drylands offers a rich opportunity to learn from the past, particularly if conducted with full stakeholder engagement. Participatory environmental assessment of past land management and restoration actions would contribute to the improvement of future management techniques in a way relevant to the concerns of people involved with or impacted by these actions. This can also help to deal with the often scant information available, conflicting values and perceptions among stakeholders, and the uncertainties inherent to complex dryland systems. In this study I applied and evaluated a participatory protocol that incorporated multi-criteria decision analysis (MCDA) tools to assess five actions in the San Simon watershed, one of the most extreme examples of degradation and human intervention in southeastern Arizona (U.S.). The participatory assessment process included a semi-structured interview, elicitation of local-based assessment criteria, prioritization of the assessment criteria, estimation of data, a MCDA-based integration and group evaluation of final results. The process was used to evaluate five combinations of grazing management, vegetation management and hydraulic structures implemented between the 1940s and 1980s. The application of this process allowed me to not only evaluate these actions in a participatory way, but also to identify and compare values and perceptions connected to the historic, cultural and scientific narratives used by three different categories of stakeholders (researchers, practitioners and land users). The revised Simos' procedure used to elicit assessment criteria weights proved useful to expose values and perceptions, source of the individual criteria priorities, while revealing conflictive points of views among the stakeholders. The outranking-facilitated participatory assessment, when compared to the unaided baseline assessment, proved useful in making stakeholder preferences explicit in the form of evaluation criteria and weights, while incorporating data and uncertainty. The specific MCDA outranking integration model used, ELECTRE IS, proved to be simple and systematically synthetic, helping stakeholders structure and re-evaluate their unaided assessments. The results of this study provide insights in how stakeholders' knowledge and views can be elicited, explored and effectively incorporated to assess and learn from past land management and restoration actions implemented in drylands.
218

Miesto gyvenamojo rajono pastatų priežiūros efektyvumo didinimas / Increment of buildings' maintenance efficiency in Urban residential district

Vilutienė, Tatjana 12 July 2004 (has links)
Research object is arranging maintenance process of the buildings of the housing estate of the city. During the research there was analyzed the efficiency of the activity of the subjects of building maintenance, macro- and micro-environmental factors, affecting building maintenance, criteria, influencing the quality of the activity of building maintenance, interest groups of the maintenance process, their objectives and possibilities to achieve them. The research aims are establishing a complex model of multi-criteria analysis of building maintenance, embracing real estate, analysis of the factors, affecting the efficiency of real estate maintenance, of the subjects, utilizing and holding the property, and of their objectives.
219

Research and modeling of the recent vertical movements of the Earth’s Сrust on the basis of geodetic measurements (samples on Lithuanian territory) / Dabartinių vertikaliųjų žemės plutos judesių tyrimas ir modeliavimas taikant geodezinius matavimus (Lietuvos teritorijos pavyzdžiu)

Anikėnienė, Asta 09 March 2009 (has links)
The thesis deals with the studies on the velocities of the recent vertical movements of the Earth’s Crust by applying correlation, regression and multi-criteria analysis of geo-parameters of the territory. The objective of the research involves the regularities of the recent vertical movements of the Earth’s Crust, the relationship with the geo-parameters of the territory, models of forecasting for movements and methodology of compiling maps on the vertical movements of the Earth’s Crust. The experimental subject matter is the territory of Lithuania. The major task of the thesis is to work out the method for estimation and modelling of the recent vertical movements of the Earth’s Crust measured by applying geodetic methods and to implement the suggested method for compilation of the map of the recent vertical movements of the Earth’s Crust within the territory of Lithuania. In order to achieve the determined target, the following tasks were solved: 1) there were determined the values of the measured recent vertical movements of the Earth’s crust from the data of the repeated levelling; 2) there were examined the regularities of the change of the recent vertical movements of the Earth’s Crust; 3) there was investigated and determined the relationship of the measured recent vertical movements of the Earth’s Crust and geo-parameters of the territory; 4) there were analysed the possibilities of application regressive models for forecasting regarding recent verticals movements of... [to full text] / Disertacijoje nagrinėjami dabartiniai vertikalieji Žemės plutos judesių greičiai taikant teritorijos georodiklių koreliacinę, regresinę ir daugiakriterinę analizę. Pagrindinis tyrimo objektas – dabartinių vertikaliųjų Žemės plutos judesių dėsningumai, sąsajos su teritorijos georodikliais, judesių prognozavimo modeliai ir vertikaliųjų Žemės plutos judesių žemėlapio sudarymo metodika. Eksperimentinis objektas – Lietuvos teritorija. Pagrindinis disertacijos tikslas – parengti geodeziniais metodais išmatuotų dabartinių vertikaliųjų Žemės plutos judesių modeliavimo bei vertinimo metodiką ir ją taikant sudaryti Lietuvos teritorijos dabartinių vertikaliųjų Žemės plutos judesių žemėlapį. Siekiant įgyvendinti užsibrėžtą tikslą, išspręsti šie uždaviniai: 1) remiantis kartotinių niveliacijų duomenimis, nustatytos išmatuotų dabartinių Žemės plutos judesių reikšmės; 2) ištirti dabartinių vertikaliųjų Žemės plutos judesių kaitos dėsningumai; 3) ištirtos ir nustatytos išmatuotų dabartinių vertikaliųjų Žemės plutos judesių ir teritorijos georodiklių sąsajos; 4) išnagrinėtos regresinių modelių taikymo dabartiniams vertikaliesiems Žemės plutos judesiams prognozuoti galimybės ir parengtos rekomendacijos juos taikyti sudarant vertikaliųjų Žemės plutos judesių žemėlapius; 5) įvertinti dabartinių vertikaliųjų Žemės plutos judesių regresiniai prognozavimo modeliai taikant daugiakriterinės analizės metodiką; 6) taikant pasiūlytą metodiką, sudarytas Lietuvos teritorijos dabartinių vertikaliųjų Žemės... [toliau žr. visą tekstą]
220

Multidimensional approaches to performance evaluation of competing forecasting models

Xu, Bing January 2009 (has links)
The purpose of my research is to contribute to the field of forecasting from a methodological perspective as well as to the field of crude oil as an application area to test the performance of my methodological contributions and assess their merits. In sum, two main methodological contributions are presented. The first contribution consists of proposing a mathematical programming based approach, commonly referred to as Data Envelopment Analysis (DEA), as a multidimensional framework for relative performance evaluation of competing forecasting models or methods. As opposed to other performance measurement and evaluation frameworks, DEA allows one to identify the weaknesses of each model, as compared to the best one(s), and suggests ways to improve their overall performance. DEA is a generic framework and as such its implementation for a specific relative performance evaluation exercise requires a number of decisions to be made such as the choice of the units to be assessed, the choice of the relevant inputs and outputs to be used, and the choice of the appropriate models. In order to present and discuss how one might adapt this framework to measure and evaluate the relative performance of competing forecasting models, we first survey and classify the literature on performance criteria and their measures – including statistical tests – commonly used in evaluating and selecting forecasting models or methods. In sum, our classification will serve as a basis for the operationalisation of DEA. Finally, we test DEA performance in evaluating and selecting models to forecast crude oil prices. The second contribution consists of proposing a Multi-Criteria Decision Analysis (MCDA) based approach as a multidimensional framework for relative performance evaluation of the competing forecasting models or methods. In order to present and discuss how one might adapt such framework, we first revisit MCDA methodology, propose a revised methodological framework that consists of a sequential decision making process with feedback adjustment mechanisms, and provide guidelines as to how to operationalise it. Finally, we adapt such a methodological framework to address the problem of performance evaluation of competing forecasting models. For illustration purposes, we have chosen the forecasting of crude oil prices as an application area.

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