Due to a variety of political, economic, and technological factors, many national electricity industries around the globe are transforming from non-competitive monopolies with centralized systems to decentralized operations with competitive business units. This process, commonly referred to as deregulation (or liberalization) is driven by the belief that a monopolistic industry fails to achieve economic efficiency for consumers over the long run. Deregulation has occurred in a number of industries such as: aviation, natural gas, transportation, and telecommunications. The most recent movement involving the deregulation of the electricity marketplace is expected to yield consumer benefit as well. To facilitate deregulation of the electricity marketplace, competitive business units must be established to manage various functions and services independently. In addition, these business units must be given physical property rights for certain parts of the transmission and distribution network in order to provide reliable service and make effective business decisions. However, partitioning a physical power grid into economically viable districts involves many considerations. We refer to this complex problem as the electrical power districting problem. This research is intended to identify the necessary and fundamental characteristics to appropriately model and solve an electrical power districting problem. Specifically, the objectives of this research are five-fold. First, to identify the issues relevant to electrical power districting problems. Second, to investigate the similarities and differences of electrical power districting problems with other districting problems published in the research literature. Third, to develop and recommend an appropriate solution methodology for electrical power districting problems. Fourth, to demonstrate the effectiveness of the proposed solution method for a specific case of electric power districting in the Republic of Ghana, with data provided by the World Bank. Finally, to develop a decision support system for the decision makers at the World Bank for solving Ghana's electrical power districting problem. / Ph. D.

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.

Approved for public release, distribution is unlimited / Numerous optimization problems involve systems with multiple and often contradictory criteria. Such contradictory criteria have been an issue for marine/naval engineering design studies for many years. This problem becomes more important when one considers novel ship types with very limited or no operational record. A number of approaches have been proposed to overcome these multiple criteria design optimization problems. This Thesis follows the Parameter Space Investigation (PSI) technique to address these problems. The PSI method is implemented with a software package called MOVI (Multi-criteria Optimization and Vector Identification). Two marine/naval engineering design optimization models were investigated using the PSI technique along with the MOVI software. The first example was a bulk carrier design model which was previously studied with other optimization methods. This model, which was selected due to its relatively small dimensionality and the availability of existing studies, was utilized in order to demonstrate and validate the features of the proposed approach. A more realistic example was based on the "MIT Functional Ship Design Synthesis Model" with a greater number of parameters, criteria, and functional constraints. A series of optimization studies conducted for this model demonstrated that the proposed approach can be implemented in a naval ship design environment and can lead to a large design parameter space exploration with minimum computational effort. / Lieutenant Junior Grade, Turkish Navy

Sous nos latitudes, l’usage des bâtiments existants et les consommations énergétiques associées (chauffage, climatisation, ventilation, eau chaude sanitaire, éclairage et autres usages) sont responsables d’impacts considérables sur l’Environnement. De plus, le renouvellement du parc existant étant inférieur à 1% par an, dans la plupart des pays développés, la réhabilitation des bâtiments constitue un levier majeur de réduction des consommations d’énergie et des émissions de gaz à effet de serre. Cependant, l’identification de stratégies optimales de réhabilitation énergétique, incluant la planification des actions dans le temps, demeure une problématique complexe pour les acteurs de la Construction. Ces travaux de thèse visent à produire des connaissances afin de contribuer à l’aide à la décision pour l’identification de programmes efficaces de réhabilitation énergétique, à partir de méthodes d’optimisation multicritères. Les solutions (programmes séquentiels de réhabilitation énergétique) sont optimisées en termes de composition et de phasage. La composition est définie par la combinaison de mesures de réhabilitation mise en oeuvre. Celles-ci concernent l’enveloppe des bâtiments (isolation thermique, remplacement des fenêtres, surfaces de fenêtres) et le remplacement des équipements de chauffage, ventilation et production d’ECS. Pour chacune des mesures, plusieurs alternatives sont envisagées. Le phasage correspond à la permutation de ces mesures, définissant la séquence de mise en oeuvre. Les solutions sont évaluées sur une base multicritère et sur le cycle de vie. Les fonctions objectifs ciblent les impacts environnementaux de l’ACV (Analyse de Cycle de Vie), des indicateurs économiques, le bien-être des occupants par le confort thermique adaptatif en été. Des modèles d’ACV et d’analyse du coût du cycle de vie, utilisant la simulation thermique dynamique pour le calcul des besoins de chauffage et des températures intérieures, ont été développés pour l’évaluation des performances des solutions. Etant donnée la nature mathématique du problème (multicritère, combinatoire, à variables discrètes et à fonctions objectifs implicites non-linéaires), deux méthodes d’optimisation multicritères sont étudiées : les algorithmes génétiques (NSGA II) et la programmation dynamique. Dans l’approche génétique, la modélisation des solutions, sous la forme d’un couple de chromosomes, permet d’identifier des programmes séquentiels efficaces de réhabilitation énergétique et d’analyser les surfaces de compromis, en termes de définition et performances des solutions, de compromis entre les critères de décision. A partir de la représentation du problème par un graphe séquentiel, la programmation dynamique permet alors de comparer les solutions approchées issues de l’algorithme génétique, ou d’approches court-termistes, au front de Pareto exact. L’optimisation exacte a également été exploitée pour analyser la sensibilité des solutions à différents paramètres de modélisation dont le comportement des occupants, l’évolution des prix de l’énergie, la durée de vie des composants de réhabilitation. Les contraintes budgétaires s’appliquant au projet de réhabilitation ont été ensuite intégrées dans un algorithme génétique multicritère sous contraintes, adapté à l’étude des stratégies de réhabilitation sous la contrainte d’un plan de financement. Enfin, l’approche génétique a été étendue depuis l’échelle du bâtiment à celle du par cet l’optimisation exacte a été utilisée pour caractériser les typologies de bâtiment en réhabilitation. L’intérêt des différentes méthodes est illustré sur une étude de cas (…) / Under our latitudes, existing buildings energy consumptions, related to heating, cooling, ventilation, domestic hot water (DHW), lighting and other uses, are responsible for significant environmental burdens. Moreover, existing buildings annual replacement rate being lower than 1%, in most developed countries, existing stock retrofit represents a major lever to reach commitments on climate change and non-renewable energy consumption mitigation. However, the identification of optimal sustainable retrofit programs, including actions planning over a time period, is still a difficult task for professionals.This thesis aims at producing knowledge in order to contribute to decision support for efficient energy retrofit programs identification, through the application of different multi-criteria optimization techniques. The solutions (sequential building energy retrofit programs) are optimized both on their content and planning. The content refers to the combination of retrofit measures considered. These address holistically building envelopes (thermal insulation, windows replacement, window to wall ratios), and the replacement of equipment for ventilation, heating and DHW production. For each of these measures, various options are considered. The planning corresponds to the permutation of these measures, defining a time sequence for implementation. The solutions are evaluated on a multi-criteria and life cycle basis. The objective functions considered target environmental impacts evaluated using LCA (Life Cycle Assessment), some financial indicators and occupants' well-being through thermal comfort in summer. Life cycle assessment and life cycle cost models, using building dynamic thermal simulation for heating load and thermal comfort evaluation, are implemented to assess solutions performances.Considering the problem mathematical nature (multi-criteria, combinatorial, discrete variables, implicit non-linear objective functions), two suitable multi-criteria optimization techniques have been studied: multi-criteria genetic algorithm (NSGA-II) and dynamic programming. In the genetic approach, the modelling of each solution by a pair of chromosomes allowed to identify efficient sequential energy retrofit programs and analyse Pareto compromise surfaces, in terms of solutions features, performances and relationships in between criteria. Then, the representation of the problem on a sequential graph enabled us to apply dynamic programming, to compare both the genetic approximate solutions, and the results of some short- term approaches to the exact Pareto frontier. The search for exact solutions also been exploited to perform sensitivity analysis on different modelling parameters such as heating temperature setting, energy prices evolution or materials lifespan. Real life budget constraints have been incorporated to build a constrained multi-criteria genetic optimisation method, suitable to study retrofit strategies under financing plans. At the end, the genetic approach has been extended from building scale to stock scale and exact optimization has been used to characterize building types in terms of energy retrofit.The benefits of these methods have been illustrated on case studies. Knowledge has been produced in terms of multi criteria optimization methodology, applied to sequential energy retrofit, and understanding of building stocks evolution. These developments contribute to decision aiding; providing decision makers with efficient energy retrofit strategies and a description of the comprise surface, at the building or building stock scale, on a multi- criteria basis, over life cycle

Dans cette thèse nous développons de nouvelles techniques pour résoudre les problèmes d'optimisation multi-critère. Ces problèmes se posent naturellement dans de nombreux domaines d'application (sinon tous) où les choix sont évalués selon différents critères conflictuels (coûts et performance par exemple). Contrairement au cas de l'optimisation classique, de tels problèmes n'admettent pas en général un optimum unique mais un ensemble de solutions incomparables, aussi connu comme le front de Pareto, qui représente les meilleurs compromis possibles entre les objectifs conflictuels. La contribution majeure de la thèse est le développement d'algorithmes pour trouver ou approximer ces solutions de Pareto pour les problèmes combinatoires difficiles. Plusieurs problèmes de ce type se posent naturellement lors du processus de placement et d'ordonnancement d'une application logicielle sur une architecture multi-coeur comme P2012, qui est actuellement développé par STMicroelectronics. / In this thesis we develop new techniques for solving multi-criteria optimization problems. Such problems arise naturally in many (if not all) application domains where choices are evaluated according to two or more conflicting criteria such as price vs. performance. Unlike ordinary optimization, such problems typically do not admit a unique optimum but a set of incomparable solutions, also known as the Pareto Front, which represent the best possible trade-offs between the conflicting goals. The major contribution of the thesis is the development of algorithms for finding or approximating these Pareto solutions for hard combinatorial problems that arise naturally in the process of mapping and scheduling application software on multi-core architectures such as P2012 which is currently being developed by ST Microelectronics.

Le Problème de Transport à la Demande (PTD), consiste à prendre en charge le transport des personnes d'un lieu de départ vers un lieu d'arrivée. Il est caractérisé par un ensemble de demandes de transport et d'un nombre de véhicules disponible. L'ultime objectif dans ce travail de thèse est d'offrir une alternative optimisée au déplacement individuel et collectif. Le PTD est classé parmi les problèmes NP-difficile, la majorité des travaux de recherche ont été concentrés sur l'utilisation des méthodes approchées pour le résoudre.Ce problème est également multicritère, la solution proposée dans ce travail permet à la fois une réduction du temps de voyage et également de la distance parcourue. Dans cette thèse, nous proposons notre contribution à l'étude et à la résolution du problème de transport à la demande multicritère et dynamique en appliquant l'algorithme de recuit simulé multi-objectif. Une grande partie de notre travail concerne la conception, le développement et la validation des approches qui permettent de donner des solutions optimales ou quasi optimales, pour un PTD. Ces approches utilisent une méthode multicritère qui s’appuie sur l’algorithme de recuit simulé. La modélisation du PTD est représentée par une architecture multi-acteurs. Cette architecture met en évidence l’aspect distribué du système ainsi que les interactions et les relations qui peuvent avoir lieu entre les différents acteurs. Nous présentons dans ce travail un Système Multi-Agents pour la planification des itinéraires des véhicules affectés au transport des voyageurs. Les agents de ce système utilisent le module d’optimisation développé dans la première partie / The Dial a Ride Problem (DRP) is to take passengers from a place of departures to places of arrivals. Different versions of the dynamic Dial a Ride Problem are found in every day practice; transportation of people in low-density areas, transportation of the handicapped and elderly persons and parcel pick-up and delivery service in urban areas. In the DRP, customers send transportation requests to an operator. A request consists of a specified pickup location and destination location along with a desired departure or arrival time. The ultimate aim is to offer an alternative to displacement optimized individually and collectively. The DRP is classified as NP-hard problem that’s why most research has been concentrated on the use of approximate methods to solve it. Indeed the DRP is a multi-criteria problem, the proposed solution of which aims to reduce both route duration in response to a certain quality of service provided. In this thesis, we offer our contribution to the study and solving the DRP in the application using a multi agent system based on the Multi-Objective Simulated Annealing Algorithm

Praktikoje dažnai tenka spręsti sudėtingus daugiakriterinius optimizavimo uždavinius, kai kriterijai būna prieštaringi, o galutinis apsisprendimas priklauso nuo sprendimų priėmėjo. Kai sprendimų priėmėjas dalyvauja sprendimo procese interaktyviai, tai jis gali koreguoti prioritetus ir siekiamus tikslus uždavinio sprendimo eigoje, kas įgalina spęsti uždavinius, turinčius daug kriterijų ir apribojimų. Be to, sprendimo priėmėjui svarbu gauti sprendinius iš visos Pareto aibės. Interaktyviam uždavinių sprendimui būtina sprendimų paramos sistema, kurios grafinė sąsaja yra pritaikyta sprendžiamam uždaviniui. Šio darbo tyrimų sritis yra interaktyvus daugiakriterinių optimizavimo uždavinių sprendimas bei sprendimų paramos sistemos. Disertacijoje nagrinėjant daugiakriterinio optimizavimo metodus, didesnis dėmesys skirtas metodams, užtikrinantiems gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje bei interaktyviems metodams. Pasiūlytas ir ištirtas daugiakriterinių optimizavimo uždavinių sprendimo būdas, leidžiantis spręsti daugiakriterinius optimizavimo uždavinius interaktyviai ir užtikrinantis gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje. Sukurta ir ištirta interaktyvi daugiakriterinių optimizavimo uždavinių sprendimų paramos sistemą, apjungianti pasiūlytą optimizavimo uždavinių sprendimo būdą, sprendimo proceso vizualizavimą ir jo lygiagretinimą. Taip pat pasiūlyta sprendimo strategija, pagal kurią sprendžiant daugiakriterinį optimizavimo uždavinį pasitelkiamas... [toliau žr. visą tekstą] / In practice, optimization problems are often multiple criteria. The criteria are usually contradictory, so the final decision depends on a decision maker. When the problem is solved interactively, the decision maker can change his/her preferences in decision process. Moreover, it is important to obtain solutions from the whole Pareto front. A decision support system adapted to the specific of the problem is essential for solving multiple criteria optimization problems interactively. The objects of research are multiple criteria optimization problems, interactive methods for solving these problems, interactive decision support systems, and application of parallel computing in decision support systems. Multiple criteria optimization methods are analyzed in the dissertation. The focus of attention is the methods for a uniform distribution of solutions on the Pareto front as well as the interactive methods. An interactive way for solving multicriteria optimization problems, which finds alternative solutions uniformly distributed on the Pareto front is proposed and investigated in this dissertation. An interactive decision support system which integrates the created interactive solving way, the decision process visualization and parallelization for multiple criteria optimization is developed. The solving strategies, when a multiple criteria optimization problem is solved interactively, using a computer cluster are developed and compared experimentally. The time required for a... [to full text]

In practice, optimization problems are often multiple criteria. The criteria are usually contradictory, so the final decision depends on a decision maker. When the problem is solved interactively, the decision maker can change his/her preferences in decision process. Moreover, it is important to obtain solutions from the whole Pareto front. A decision support system adapted to the specific of the problem is essential for solving multiple criteria optimization problems interactively. The objects of research are multiple criteria optimization problems, interactive methods for solving these problems, interactive decision support systems, and application of parallel computing in decision support systems. Multiple criteria optimization methods are analyzed in the dissertation. The focus of attention is the methods for a uniform distribution of solutions on the Pareto front as well as the interactive methods. An interactive way for solving multicriteria optimization problems, which finds alternative solutions uniformly distributed on the Pareto front is proposed and investigated in this dissertation. An interactive decision support system which integrates the created interactive solving way, the decision process visualization and parallelization for multiple criteria optimization is developed. The solving strategies, when a multiple criteria optimization problem is solved interactively, using a computer cluster are developed and compared experimentally. The time required for a... [to full text] / Praktikoje dažnai tenka spręsti sudėtingus daugiakriterinius optimizavimo uždavinius, kai kriterijai būna prieštaringi, o galutinis apsisprendimas priklauso nuo sprendimų priėmėjo. Kai sprendimų priėmėjas dalyvauja sprendimo procese interaktyviai, tai jis gali koreguoti prioritetus ir siekiamus tikslus uždavinio sprendimo eigoje, kas įgalina spęsti uždavinius, turinčius daug kriterijų ir apribojimų. Be to, sprendimo priėmėjui svarbu gauti sprendinius iš visos Pareto aibės. Interaktyviam uždavinių sprendimui būtina sprendimų paramos sistema, kurios grafinė sąsaja yra pritaikyta sprendžiamam uždaviniui. Šio darbo tyrimų sritis yra interaktyvus daugiakriterinių optimizavimo uždavinių sprendimas bei sprendimų paramos sistemos. Disertacijoje nagrinėjant daugiakriterinio optimizavimo metodus, didesnis dėmesys skirtas metodams, užtikrinantiems gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje bei interaktyviems metodams. Pasiūlytas ir ištirtas daugiakriterinių optimizavimo uždavinių sprendimo būdas, leidžiantis spręsti daugiakriterinius optimizavimo uždavinius interaktyviai ir užtikrinantis gaunamų sprendinių tolygų pasiskirstymą Pareto aibėje. Sukurta ir ištirta interaktyvi daugiakriterinių optimizavimo uždavinių sprendimų paramos sistemą, apjungianti pasiūlytą optimizavimo uždavinių sprendimo būdą, sprendimo proceso vizualizavimą ir jo lygiagretinimą. Taip pat pasiūlyta sprendimo strategija, pagal kurią sprendžiant daugiakriterinį optimizavimo uždavinį pasitelkiamas... [toliau žr. visą tekstą]

During the past several decades, agricultural intensification has been crucial to increase the food supply. Several processes related to intensification are very detrimental to the environment, particularly biodiversity. Today, agriculture is facing the challenge of satisfying its demand for food while improving its environmental sustainability. Knowledge of the shape of the relationship between biodiversity and intensity is necessary to determine both where conservation policies will be most effective and how to allocate intensity to reconcile production and biodiversity. Few empirical studies on this relationship exist, and the influence of the spatial arrangement of intensity on biodiversity remains untested. This Ph.D. thesis determined how to target both agricultural intensity and its spatial allocation for meeting production and conservation objectives of farmlands. To answer this research question, we used a country-scaled approach that combined two France-scaled databases that describe agriculture and farmland birds. We characterized a nationwide gradient of agricultural intensity and studied a farmland bird community along this gradient, using several trait-based descriptors (specialization, trophic level, and species main habitat). Agricultural intensity and bird communities were described at the Small Agricultural Region (SAR; mean width = 22.4 km) level. As a first step, we developed a novel method to estimate an intensity indicator that was based on Input Costs/ha, with SAR resolution. This indicator provides a continuous intensity measure that is relevant across different types of agricultural systems. Secondly, we investigated the effects of a gradient of land uses (grassland to arable land) and its heterogeneity on the bird community. We found habitat specialists suffered from habitat loss, while generalists benefited from heterogeneity. Thirdly, we showed that the community responded significantly to intensity, with winner species replacing loser species along the gradient. The shift between losers and winners was sharper at low intensities. Interestingly, spatial aggregation of intensity had a strengthening effect on the bird community. Finally, the relationships linking intensity to the bird community, food production, and economic performance were integrated into a model aimed at optimizing intensity allocation. Optimal allocations reached win-no-lose solutions with the three criteria. They corresponded to targeted intensity modifications: many small changed, favoring homogeneous, extensive clusters, were optimal within an extensification scenario; while a few large changes, favoring heterogeneity, were optimal within an intensification scenario. We provide one of the first studies demonstrating that spatial aggregation of intensity can influence the biodiversity/intensity relationship. Our results also provide an opportunity to improve the effectiveness of conservation policies, at national scales, with spatial targeting: opposite targeting should be performed either to maximize biodiversity benefits or to increase production, while mitigating biodiversity impacts. Our results highlight the importance of mixed allocation strategies between land sparing/sharing extremes. In order to put these opportunities into effect, further research should address the technical solutions that achieve intensity modification at the farm level and design targeted policies that benefit biodiversity and other environmental criteria

Uppsatsen undersöker hur Emballator Växjöplast prioriterar och resonerar kring aspekterna volymutnyttjande, plocktid, säkerhet, kapitalbindning och servicenivå vid optimering av deras färdigvarulager. Författarna kom fram till följande slutsats: Fallföretaget prioriterar säkerhet högst för att skydda individen Servicenivå prioriteras efter säkerhet då de arbetar kundfokuserat. Efter servicenivå prioriteras volymutnyttjande för att minska sin externlagring. Plocktid prioriteras efter volymutnyttjande där målsättningen är att undvika nyanställningar. Sist prioriteras kapitalbindning då denna inte är fokus för logistikfunktionen.   Vidare undersöker författarna hur en multi-criteria optimization av aspekterna vid optimering av färdigvarulagret kan gå till. Författarna kommer fram till följande slutsatser: The main criteria method är bäst lämpad optimeringsmetod. Volymutnyttjande ska minimeras givet att resterande aspekter uppfyller respektive bivillkor. De flesta förvaringsmetoder och artikelplaceringar uppfyller aspekternas bivillkor Bäst lämpad förvaringsmetod och artikelplacering grundas därför på vilken som möjliggör bäst volymutnyttjande. Slutligen utvärderas Emballator Växjöplasts nuvarande färdigvarulager sett till aspekterna utifrån analysen för frågeställning 2. Här presenteras även kortsiktiga och långsiktiga förbättringsförslag. Författarna kom fram till följande slutsats: Deras nuvarande förpackning, förvaringsmetod samt artikelplacering tillgodoser respektive bivillkor men kan förbättras sett till the main criteria, volymutnyttjande. Ett kortsiktigt förbättringsförslag genom att utföra en liknande artikelplacering på bättre sätt kan upp till 38-57 fler pallar rymmas på färdigvarulagret. Ett långsiktigt förbättringsförslag genom att kombinera traditionella pallställage och drive-through eller push-back-hyllor, kan totala antal pallplatser på färdigvarulagret öka med 18,4 %. / The essay examines how Emballator Växjöplast prioritize and reason among the aspects safety, service level, utilization rate, order picking time and capital tied up in inventory when optimizing their finished goods warehouse. The authors came to the following conclusion: Firstly, they prioritize safety the highest to protect the individuals within the warehouse. Service level is prioritized secondly because they operate with a customer focus. After service level utilization rate is prioritized to lower their need for external storage. Order picking time is prioritized after utilization rate with the goal to avoid the need for employing more operators within the warehouse. Lastly capital tied up in inventory is prioritized because the aspect is not in focus for the logistics department.   Moreover, the authors investigate how multi-criteria optimization as an optimization method can be used when optimizing a finished goods warehouse considering several contradictive aspects and the conclusion is: The main criteria method is best suited in optimization method. Utilization rate is the main criteria and the other aspects are constraints. The majority of storage systems and storage assignment policy are within the constraints. The best storage systems and storage assignment policy is therefore mainly determined by the main criteria.   Lastly a discussion regarding the finished goods warehouse is held and both short term and long term improvements regarding the aspects are presented. The conclusions made by the authors are as follows: Their current packaging, storage systems and storage assignment policy is sufficient in terms of the different constraints but the main criteria can be improved. Short term improvements are to use a similar storage assignment policy in a better way and enable room for 38-57 more pallets in the finished goods warehouse. Long term improvements are to improve both storage assignment policy and the storage system. By combining traditional racks with some other storage system such as drive-through or push-back-shelves the number of pallets that can fit within the warehouse can increase by 18,4%.