Τα τελευταία χρόνια στις περισσότερες χώρες έχει ολοκληρωθεί η κατασκευή οδικών δικτύων και το ενδιαφέρον των φορέων οδοποιίας έχει στραφεί στη διαχείριση των υφιστάμενων οδικών κατασκευών. Το κυριότερο τμήμα της Διαχείρισης Οδικών Δικτύων καταλαμβάνει η Διαχείριση Οδοστρωμάτων. Τα Συστήματα Διαχείρισης Οδοστρωμάτων έχουν ως στόχο την οικονομική διαχείριση των οδοστρωμάτων και χρησιμοποιούν τεχνητή νοημοσύνη για να καταλήξουν στη βέλτιστη και οικονομικά αποδοτικότερη κατανομή των διαθέσιμων πόρων. Το ευφυές σύστημα που διαθέτουν καταφέρνει να εντοπίζει τη βέλτιστη λύση που ελαχιστοποιεί το κόστος συντήρησης αλλά δεν λαμβάνουν υπόψη τους το αντίκτυπο της επιδείνωσης της κατάστασης του οδοστρώματος στο χρήστη και στο περιβάλλον. Στην παρούσα εργασία χρησιμοποιείται ένας γενετικός αλγόριθμος και αναζητείται η βέλτιστη λύση που ελαχιστοποιεί το γενικευμένο κόστος, το οποίο περιλαμβάνει το κόστος συντήρησης, το κόστος του χρήστη εξαιτίας της κατάστασης του οδοστρώματος και το περιβαλλοντικό κόστος. Τα δεδομένα του προβλήματος αφορούν την κατάσταση των τμημάτων που πρόκειται να συντηρηθούν, το είδος της οδού στο οποίο ανήκουν τα τμήματα οδοστρώματος, τα στοιχεία φθορών κάθε τμήματος, τα διαθέσιμα είδη συντήρησης, το ύψος της χρηματοδότησης και τα κυκλοφοριακά χαρακτηριστικά της περιοχής στην οποία βρίσκονται τα υπό συντήρηση τμήματα. Ο αλγόριθμος κατασκευάζει γονίδια επιλέγοντας είδος συντήρησης για κάθε τμήμα και για κάθε χρόνο συμπεριλαμβανομένης και της επιλογής να μην γίνει καμία συντήρηση σε κάποιο χρόνο. Τα γονίδια ελέγχονται με βάση περιορισμούς που έχουν τεθεί από τα μοντέλα φθορών κάθε τμήματος και επιλέγονται να μεταφερθούν στην επόμενη γενιά αυτά που συνδυάζουν το ελάχιστο κόστος και το μέγιστο επίπεδο λειτουργικότητας στο οδόστρωμα. Η διαφορά του μοντέλου σε σχέση με τα κοινά συστήματα διαχείρισης οδοστρωμάτων έγκειται περισσότερο στις υπολογιστικές απαιτήσεις του συστήματος καθώς η εφαρμογή γενετικού αλγορίθμου οδηγεί γρηγορότερα σε λύση από ότι οι κλασικές μέθοδοι βελτιστοποίησης όπως π.χ. ο γραμμικός προγραμματισμός. Η καταλληλότητα και η ευκολία προσαρμογής των γενετικών αλγορίθμων σε προβλήματα διαχείρισης οδοστρωμάτων επαληθεύεται στην παρούσα εργασία. Το σύστημα καταφέρνει να εντοπίζει το βέλτιστο χρόνο με την οικονομικότερη συντήρηση του κάθε τμήματος του οδικού δικτύου και την πιο φιλική λύση για το χρήστη της οδού και το περιβάλλον. / In recent years the focus of the transportation authorities, researchers and practitioners is being shifted from the construction of new roads to the management of existing road structures and especially to road pavements. Pavement Management Systems are widely used and are continuously being improved because they can lead to considerable fund savings and/or to higher levels of service of road pavements. In this work, a model for pavement maintenance and rehabilitation planning and optimal resource allocation is presented. The objective function aims at minimizing a generalized cost parameter which includes a number of monetary cost components and no monetary impacts. In particular, the objective function consists of the following components: (1) agency cost (the cost of applying the selected maintenance and rehabilitation strategy), (2) user costs (they include vehicle operating cost for fuel consumption, vehicle maintenance and depreciation, traffic delay cost, accident cost, discomfort cost, and delay cost due to maintenance works and (3) environmental impact costs due to traffic pollution and noise. The above cost components are considered with regard to the existing pavement condition levels which are represented by the PSI index. Pavement condition deterioration is assessed through deterministic models that have been developed earlier by our team based on expert opinions and fuzzy systems considering pavement related and traffic parameters, i.e., pavement age, pavement strength, pavement construction quality and traffic loads. The maintenance and rehabilitation treatments are considered with regard to their cost and effectiveness characteristics. Besides the pavement condition deterioration functions, other constraints of the model include budgetary availability (total and individually for different highway groups), threshold values for the minimum accepted pavement condition levels (by highway class), desirable pavement condition levels (by highway class), maintenance and rehabilitation treatment applicability and effectiveness, etc. Due to the size and complexity of the problem (non linear functions), a genetic algorithm has been used as an optimization tool. The algorithm forms solutions by considering applicable maintenance treatments at each pavement section and year within the analysis period. Each solution is checked against all constraints to ensure the feasibility of the solution. No feasible solutions are discarded and new solutions are generated until the required offspring solutions are obtained. The optimization runs over several road sections with different traffic and pavement condition characteristics and within a time span of 10 years. The budgetary or the minimum accepted pavement condition constraints can be altered in order to get a Pareto-front set of optimal solutions for a particular application. Preliminary evaluation indicates that the model provides reasonable results in terms of the appropriate selection of maintenance and rehabilitation treatments and the time of application.

Abstract Peatland drainage for forestry, agriculture and peat extraction results in runoff rich in organic matter, sediments and nutrients. This has a significant effect on downstream ecosystems. Therefore, water purification using sedimentation basins and wetlands is required in environmental permits for peat extraction in Finland, to reduce downstream impacts. Due to increasingly strict environmental regulations, more advanced water purification methods need to be developed. Using field measurements, laboratory experiments and hydrological/hydraulic modelling, this thesis sought to develop new methods based on: i) more refined hydrological information related to runoff and pollutant load control and ii) hydraulic design of sedimentation basins used in chemical purification. The hydrology of three peatland forestry and two drained peat extraction areas in northern Finland was studied and simulated using the DRAINMOD 6.1 hydrological model. Watertable depth (WTD) and drainage outflow were recorded continuously during several years and the data were used for model calibration and validation. Despite some under- and over-estimation of certain events, WTD fluctuations were simulated quite accurately for all peatland areas. The results demonstrated that DRAINMOD 6.1 can satisfactorily simulate WTD fluctuations in a cold climate such as northern Finland, but the model did not simulate drainage outflow adequately. Chemical treatment facilities were optimised using 3D computational fluid dynamic (CFD) models. COMSOL Multiphysics 5.1 was employed to evaluate the influence of inlet design on treatment efficiency in commonly used treatment basins without any barrier, and for optimization of barrier design through gravity-driven hydraulic flocculators. The results showed that inlet design had a significant effect on treatment efficiency. Several barrier designs were simulated and the best combination was tested for different distances between barriers, to find a geometry ratio and flow depth producing optimal mixing conditions for the treatment process. / Tiivistelmä Turvemaiden ojitus metsätaloutta, maataloutta ja turvetuotantoa varten lisää orgaanisen aineen, kiintoaineineen ja ravinteiden huuhtoutumista alapuolisiin vesistöihin. Lisääntyneellä kuormituksella voi olla merkittäviä vaikutuksia vesiekosysteemeihin, minkä vuoksi turvetuotannon ympäristöluvissa vaaditaan valumavesien puhdistamista mm. laskeutusaltaiden ja pintavalutuskenttien avulla. Tiukentuneiden vesiensuojelumääräysten vuoksi tarvitaan uusia vesiensuojelumenetelmiä sekä tulee tehostaa jo käytössä olevien menetelmien toimintaa. Tämän työn tavoitteena on suositella uusia menetelmiä perustuen I) entistä tarkempaan hydrologiseen tietoon valunnasta ja vesistökuormituksesta ja II) kemiallisen vesienpuhdistuksen yhteydessä käytettävien laskeutusaltaiden hydrauliseen suunnitteluun. Tämä väitöstyö rakentuu maastossa ja laboratoriossa tehtyjen tutkimusten sekä hydrologisen/hydraulisen mallinnuksen varaan. Valuma-alueiden hydrologiaa tutkittiin ja mallinnettiin kolmella turvemetsäalueella ja kahdella turvetuotantoalueella Pohjois-Suomessa. Ojituksen hydrologisten vaikutusten arviointiin käytettiin DRAINMOD 6.1 ohjelmaa, jonka kalibrointia ja validointia varten kerättiin jatkuvatoimisilla antureilla aineistoa pohjaveden pinnankorkeuksista ja virtaamasta useiden vuosien ajalta. Mallin avulla voitiin pohjaveden pinnan vaihtelut kuvata yleisesti melko hyvin kaikilla tutkimusalueilla yksittäisistä sadanta-valuntatapahtuminen yli- tai aliarvioinneista huolimatta. Saadut tulokset osoittavat, että DRAINMOD 6.1 ohjelmalla voidaan riittävällä tarkkuudella simuloida pohjaveden pinnan vaihteluita kylmässä ilmastossa, kuten Pohjois-Suomessa, mutta malli ei soveltunut hyvin ojitusalueelta lähtevän valunnan tarkkaan määrittämiseen. Kemiallisen vesienpuhdistusrakenteiden optimointiin käytettiin COMSOL Multiphysics 5.1 ohjelmaa, jolla voidaan toteuttaa ja laskea veden virtauksia kolmessa dimensiossa (computational fluid dynamic, CFD, model). Mallilla arvioitiin kemikalointialtaan tuloaukon rakenteen vaikutuksia tyypillisesti kemikaloinnissa käytetyn allasrakenteen puhdistustehokkuuteen. Lisäksi mallilla mitoitettiin virtausesteitä optimaalisen sekoittumisolosuhteiden saamiseksi ja puhdistustehokkuuden parantamiseksi painovoimaisesti toimivissa flokkausaltaissa (hidas sekoitus). Saadut tulokset osoittavat, että laskeutusaltaiden tuloaukon rakenteella on merkittävä vaikutus kemikaloinnissa saavutettuun puhdistustehokkuuteen. Lisäksi työssä esitettiin optimaalisia virtausesteiden mitoituksia (geometria, esteiden välinen etäisyys, virtaussyvyys yms.) puhdistuksen kannalta parhaiden mahdollisten sekoitusolosuhteiden saavuttamiseksi.

Humanitarian aid and disaster relief are delivered in times of crises or natural disasters, such as after a conflict or in response to a hurricane, typhoon, or tsunami. Different from regular aid programs, aid and relief are provided to deal with emergency and immediate local areas, and to shelter affected people and refugees impacted by sudden traumatic events. There is evidence that natural and man-made disasters are increasing in numbers all around the world, affecting hundreds of millions of people every year. In spite of this fact, only in recent years – beginning in 2005 – has management of the supply chain of resources and materials for humanitarian aid and disaster relief been a topic of interest for researchers. Consequently, the academic literature in this field is comparatively new and still sparse, indicating a requirement for more academic studies. As a key part of the C-Change International Community-University Research Alliance (ICURA) project for managing adaptation to environmental change in coastal communities of Canada and the Caribbean, this thesis develops a framework and analytical model for domestic supply chain management in humanitarian aid and disaster relief in the event of severe storm and flooding in the Canadian C-Change community of Charlottetown, Prince Edward Island. In particular, the focus includes quantitative modeling of two specific aspects during the preparedness phase for emergency management: (1) inventory prepositioning and (2) transportation planning. In addition, this thesis proposes and analyses the characteristics of an effective supply chain management framework in practice to assist Canadian coastal communities in improving their preparation and performance in disaster relief efforts. The results indicate Charlottetown system effectiveness and decreased time to assist affected people are improved by distributing central emergency supply among more than one base station.

[pt] O Índice de Desenvolvimento Humano (IDH) foi criado pela Organização das Nações Unidas (ONU) em 1975, sendo um índice composto que mede a obtenção da média do país em três aspectos básicos que são a expectativa de vida, a educação e a renda familiar. O IDH é um indicador alternativo ao Produto Nacional Bruto (PNB), que mede a riqueza de uma nação, acrescentando a este dois indicadores sociais abrangentes, a saber: a educação e a saúde. O IDH torna-se útil na medida em que chama a atenção das pessoas responsáveis politicamente pelo país, no sentido de se aterem mais à área social, ou seja, de verificarem como está o desenvolvimento integral do país permitindo inclusive a comparação com outros. Além do IDH, o estudo descreve índices que medem a condição humana, HPI-1 e HPI- 2, para medirem índices de pobreza em países em desenvolvimento e em países selecionados, o GDI e GEM, que são índices relacionados ao sexo, tanto para desenvolvimento como participação e o IDH-M que é um índice apropriado para municípios. O estudo faz também um diagnóstico da situação do Brasil e de sua evolução, desde a criação do índice. Serão propostos modelos em pesquisa operacional para otimização do IDH, o que facilitará e agilizará a tomada de decisões por parte dos governantes, que poderão tomar suas decisões baseadas agora num modelo matemático que certamente trará mais retornos de investimento sobre o capital empregado. As variáveis principais do problema serão a saúde, educação e a renda da população. As soluções e sugestões a serem apresentadas terão como meta básica o menor custo e de mais rápida implementação. / [en] The Human Development Index (HDI) is a compound index that measures the levels of a country in three basic aspects: life expectancy, education level and the family income. The HDI indicates an alternative to the Gross Domestic Product (GDP), which measures the overall wealth of a country, adding two social indexes: the education pattern and the health level. The HDI is a useful index because it shows the social area to people who have political responsabilities in a country, suggesting them the evaluation of the country development including social aspects, and permitting the comparison with the other countries. Besides the HDI, the study describes indexes which measure the human condition, HPI-1 and HPI-2, of poverty in development and in selected countries, the GDI and GEM, which are gender related indexes to check development and participation, and the HDI-M which is an appropriate index to measure the human condition in an urban environment. The study makes a diagnosys of the Brazilian situation and evolution, since the creation of these indexes. The dissertation proposes HDI optimization models. Such proposal might simplify and improve the efficiency of the decision making process. In this way, public officials may take their decisions based on a mathematical model which will increase the ratio benefits and investment costs.

In this study, methodologies for modeling grey uncertainty in water resources systems are developed, specifically for the problems in two identified areas in water resources: waste load allocation in streams and floodplain planning. A water resources system is associated with some degree of uncertainty, due to randomness of hydrologic and hydraulic parameters, imprecision and subjectivity in management goals, inappropriateness in model selection, inexactness of different input parameters for inadequacy of data, etc. Uncertainty due to randomness of input parameters could be modeled by the probabilistic models, when probability distributions of the parameters may be estimated. Uncertainties due to imprecision in the management problem may be addressed by the fuzzy decision models. In addition, some parameters in any water resources problems need to be addressed as grey parameters, due to inadequate data for an accurate estimation but with known extreme bounds of the parameter values. Such inexactness or grey uncertainty in the model parameters can be addressed by the inexact or grey optimization models, representing the parameters as interval grey numbers. The research study presented in this thesis deals with the development of grey and fuzzy optimization models, and the combination of the two for water resources systems decision-making. Three grey fuzzy optimization models for waste load allocation, namely (i) Grey Fuzzy Waste Load Allocation Model (GFWLAM), (ii) two-phase GFWLAM and (iii) multiobjective GFWLAM, and a Grey Integer Programming (GIP) model for floodplain planning, are developed in this study. The Grey Fuzzy Waste Load Allocation Model (GFWLAM) for water quality management of river system addresses uncertainty in the membership functions for imprecisely stated management goals of the Pollution Control Agency (PCA) and dischargers. To address the imprecision in fixing the boundaries of membership functions (also known as membership parameters), the membership functions themselves are treated as imprecise in the model and the membership parameters are expressed as interval grey numbers. The conflict between the fuzzy goals of PCA and dischargers is modeled using the concept of fuzzy decision, but because of treating the membership parameters as interval grey numbers, in the present study, the notion of ‘fuzzy decision’ is extended to the notion of ‘grey fuzzy decision’. A terminology ‘grey fuzzy decision’ is used to represent the fuzzy decision resulting from the imprecise membership functions. The model provides flexibility for PCA and dischargers to specify their aspirations independently, as the membership parameters for membership functions are interval grey numbers in place of a deterministic real number. In the solution, optimal fractional removal levels of the pollutants are obtained in the form of interval grey numbers. This enhances the flexibility and applicability in decision-making, as the decision-maker gets a range of optimal solutions for fixing the final decision scheme considering technical and economic feasibility of the pollutant treatment levels. The methodology is demonstrated with the case studies of a hypothetical river system and the Tunga-Bhadra river system in Karnataka, India. Formulation of GFWLAM is based on the approach for solving fuzzy multiple objective optimization problem using max-min as the operator, which usually may not result in a unique solution. The two-phase GFWLAM captures all the alternative optimal solutions of the GFWLAM. The solution technique in the Phase 1 of two-phase GFWLAM is the same as that of GFWLAM. The Phase 2 maximizes upper bounds and minimizes lower bounds of decision variables, keeping the optimal value of goal fulfillment level same as obtained in the Phase 1. The two-phase GFWLAM gives the unique, widest, intervals of the optimal fractional removal levels of pollutant corresponding to the optimal value of goal fulfillment level. The solution increases the widths of interval-valued fractional removal levels of pollutants by capturing all the alternative optimal solutions and thus enhances the flexibility and applicability in decision-making. The model is applied to the case study of Tunga-Bhadra river system, which shows the existence of multiple solutions when the GFWLAM is applied to the same case study. The width of the interval of optimal fractional removal level plays an important role in the GFWLAM, as more width in the fractional removals implies a wider choice to the decision-makers and more applicability in decision-making. The multiobjective GFWLAM maximizes the width of the interval-valued fractional removal levels for providing a latitude in decision-making and minimizes the width of goal fulfillment level for reducing the system uncertainty. The multiobjective GFWLAM gives a new methodology to get a satisfactory deterministic equivalent of a grey fuzzy optimization problem, using the concept of acceptability index for a meaningful ranking between two partially or fully overlapping intervals. The resulting multiobjective optimization model is solved by fuzzy multiobjective optimization technique. The consistency of the solution is verified by solving the problem with fuzzy goal programming technique. The multiobjective GFWLAM avoids intermediate submodels unlike GFWLAM, so that the solution from a single deterministic equivalent of the GFWLAM adequately covers all possible situations. Although the solutions obtained from multiobjective GFWLAM provide more flexibility than those of the GFWLAM, its application is limited to grey fuzzy goals expressed by linear imprecise membership functions only, whereas GFWLAM has the capability to solve the model with any monotonic nonlinear imprecise membership functions also. The methodology is demonstrated with the case studies of a hypothetical river system and the Tunga-Bhadra river system in Karnataka, India. The Grey Integer Programming (GIP) model for floodplain planning is based on the floodplain planning model developed by Lund (2002), to identify an optimal mix of flood damage reduction options with probabilistic flood descriptions. The model demonstrates how the uncertainty of various input parameters in a floodplain planning problem can be modeled using interval grey numbers in the optimization model. The GIP model for floodplain planning does not replace a post-optimality analysis (e.g., sensitivity analysis, dual theory, parametric programming, etc.), but it provides additional information for interpretation of the optimal solutions. The results obtained from GIP model confirm that the GIP is a useful technique for interpretation of the solutions particularly when a number of potential feasible measures are available in a large scale floodplain planning problem. Though the present study does not directly compare the GIP technique with sensitivity analysis, the results indicate that the rigor and extent of post-optimality analyses may be reduced with the use of GIP for a large scale floodplain planning problem. Application of the GIP model is demonstrated with the hypothetical example as presented in Lund (2002).

Il est bien connu que l'écosystème industriel territorial représente aujourd'hui un enjeu majeur dans les politiques d’aménagement du territoire. De ce fait, il constitue un système d’action où les différents acteurs impliqués utilisent des différentes approches et dont les objectifs ne sont pas toujours proches et les points de vue parfois conflictuels. Toutes approches confondues, un type idéal de tableau de bord incorporant des indicateurs et centré sur le pilotage de la performance émerge aujourd'hui de la littérature.Dans ce contexte, il apparaît l'importance du traitement de la problématique d'évaluation d'un écosystème industriel territorial et plus précisément l'évaluation de la performance d'un système de distribution dans une zone portuaire : l’hinterland. Ce sujet n'a pas été assez développé dans la littérature puisqu’il n’a pas été traité selon une approche pluridisciplinaire.Cette problématique est caractérisée par la forte liaison entre l'infrastructure de transport, le système territorial et les zones logistiques suite à l'échange des flux de marchandises dans le territoire à travers l'infrastructure de transport. L'apport théorique de ce travail se présente dans la démarche originale d'investigation qui met en contribution des approches théoriques différentes dans le but de comprendre et résoudre une problématique relative à deux systèmes complexes (le système logistique et le système territorial). Pour plus de clarté, ce travail s'agit d'une aide à la décision à travers la réflexion sur les solutions de distribution en intégrant les spécificités territoriales et non pas comme un outil d'optimisation des tournées ou de l'organisation logistique. / It is well known that the territorial industrial ecosystem is now a major issue in territory planning policies. As a result, it constitutes a system of action in which the various actors involved use different approaches and whose objectives are not always close and sometimes conflicting points of view. In all approaches, an ideal type of dashboard incorporating indicators and focusing on performance pilotage is emerging today from the literature.In this context, it appears the importance of the treatment of the problem of evaluation of a territorial industrial ecosystem and more precisely the evaluation of the performance of a distribution system in a port area: the hinterland.This subject has not been sufficiently developed in the literature since it has not been treated with a multidisciplinary approach.This problem is characterized by the strong link between the transport infrastructure, the territorial system and the logistics zones following the exchange of goods flows in the territory through the transport infrastructure.The theoretical contribution of this work is presented in the original investigation approach, which involves different theoretical approaches in order to understand and solve a problem related to two complex systems (the logistics system and the territorial system).For clarity, this work is a decision aid through the reflection on distribution solutions by integrating territorial specificities and not as a tool for optimizing tours or logistics organization.

Made available in DSpace on 2016-06-02T19:50:27Z (GMT). No. of bitstreams: 1 TeseCRNS.pdf: 1772351 bytes, checksum: 17b2dc82dae0e985204bfa2fd68f873b (MD5) Previous issue date: 2005-04-29 / Universidade Federal de Minas Gerais / The management of manufacturing systems have become more complex, once that new products are arising, product demands are uncertain, life cycles get shorter, and a wide variety of products compete for common resources. This thesis deals with the design and planning of discrete manufacturing systems, based on open queueing network models to support the decision making of capacity allocation. As manufacturing systems may be represented by generalized queueing networks, and there are no exact solution methods, here is employed the decomposition approximate method to evaluate the performance of systems under different configurations. It is shown in the thesis how these approximations are suitable and effective to estimate the work-in-process (WIP) and the production leadtime of an actual metallurgical industry queueing network. It is also shown that discrete capacity allocation models, based on the approximations, are effective to evaluate and optimize the performance of the case study under different configurations. Trade-off curves between capacity investment and WIP are generated and are useful not only to support a manager to estimate how much capacity he/she should allocate, but also to decide where it should be allocated in the queueing network. These curves also support the decision making in terms of capacity, if the variability of the external arrivals, the product mix and/or the throughput for the network change. Besides adding capacity, partitioning the facility is another alternative to reduce the system complexity. This thesis also approaches the focused factory design problem, involving the partition of the facility into smaller shops and the capacity allocation in each shop. Again, the decomposition approximations were employed to evaluate the system performance. Despite its importance, this problem has rarely been reported in the literature. In this thesis, the goal is to reduce the system complexity either from the product management point of view or from the workstation management point of view. From the product management point of view, a model whose complexity constraint is na upper limit on the production leadtime variance of the products passing through the network was studied. From the workstation management point of view, the complexity constraint of the model keeps constant the expected waiting time of a product at a workstation, once it waits for being served. It is shown through these models for some instances that the partition of the facility into smaller shops decreases the complexity system without necessary capacity additional investments. Futhermore, sometimes it is possible to keep the network performance (or even to improve it), partitioning the network into smaller shops which need less capacity than the original configuration with a single shop. / A gestão de sistemas de manufatura tem se tornado mais complexa na medida em que novos produtos estão surgindo, a demanda de produtos é incerta, os ciclos de vida são mais curtos e uma grande variedade de produtos competem pelos mesmos recursos. Esta tese trata o projeto e planejamento de sistemas discretos de manufatura, baseados em modelos de redes de filas abertas, para auxiliar no processo de tomada de decisões. Porque sistemas de manufatura podem ser representados por redes de filas genéricas, e não existem métodos exatos de solução, aqui é empregado o método aproximado de decomposição para avaliar o desempenho dos sistemas em diferentes configurações. Mostra-se nesta tese que estas aproximações são adequadas e efetivas para estimar os estoques em processo (WIP) e o leadtime de produção de uma rede de manufatura real de uma indústria metal-mecânica. Mostra-se ainda que os modelos de alocação de capacidade discreta, baseados nestas aproximações, também são efetivos para avaliar e otimizar o desempenho da rede do estudo de caso em diferentes configurações. Curvas de trade-off entre investimento em capacidade e WIP são geradas e são úteis não somente para auxiliar um gerente a estimar quanto alocar de capacidade, mas também para decidir onde alocá-la na rede de filas. As curvas também auxiliam a tomada de decisões em termos de capacidade, se a variabilidade das chegadas externas, o mix de produtos e/ou a taxa de produção da rede mudam. Além de adicionar capacidade, a partição da instalação é outra alternativa para reduzir a complexidade do sistema. Esta tese também aborda o problema de projeto de fábrica focalizada, envolvendo a partição da instalação em subplantas e a alocação de capacidade em cada estação das subplantas. Novamente, as aproximações por decomposição foram utilizadas para avaliar e otimizar o desempenho do sistema. Apesar de sua importância, este problema tem sido muito pouco reportado em literatura. Nesta tese, o objetivo é reduzir a complexidade do sistema do ponto de vista da gestão do produto, ou do ponto de vista da gestão da estação. Do ponto de vista da gestão do produto, é apresentado um modelo cuja restrição de complexidade é um limitante superior para a variância do leadtime dos produtos na rede. Do ponto de vista da gestão da estação, a restrição de complexidade do modelo fixa o tempo médio de espera de um produto na estação, quando há espera. Mostra-se, por meio destes modelos para alguns casos que, a partição da instalação em subplantas reduz a complexidade do sistema, sem necessidade de investimentos adicionais em capacidade. Além disso, algumas vezes, é possível manter (ou até melhorar) o desempenho da rede, particionando-a em subplantas que necessitam de menos capacidade do que a configuração original com uma planta única.

Les réseaux maillés sans fil sont une solution efficace, de plus en plus mise en œuvre en tant qu’infrastructure, pour interconnecter les stations d’accès des réseaux radio. Ces réseaux doivent absorber une croissance très forte du trafic généré par les terminaux de nouvelle génération. Cependant, l’augmentation du prix de l’énergie, ainsi que les préoccupations écologiques et sanitaires, poussent à s’intéresser à la minimisation de la consommation énergétique de ces réseaux. Ces travaux de thèse s’inscrivent dans les problématiques d’optimisation de la capacité et de la minimisation de la consommation énergétique globale des réseaux radio maillés. Nous définissons la capacité d’un réseau comme la quantité de trafic que le réseau peut supporter par unité de temps. Ces travaux s’articulent autour de quatre axes. Tout d’abord, nous abordons le problème d’amélioration de la capacité des réseaux radio maillés de type WIFI où l’accès au médium radio se base sur le protocole d’accès CSMA/CA. Nous mettons en lumière, les facteurs déterminants qui impactent la capacité du réseau, et l’existence d’un goulot d’étranglement qui limite cette capacité du réseau. Ensuite, nous proposons une architecture de communication basée sur l’utilisation conjointe de CSMA/CA et de TDMA afin de résoudre ce problème de goulot d’étranglement. Dans la deuxième partie de cette thèse, nous nous intéressons aux réseaux maillés sans fil basés sur un partage des ressources temps-fréquence. Afin de calculer des bornes théoriques sur les performances du réseau, nous développons des modèles d’optimisation basés sur la programmation linéaire et la technique de génération de colonnes. Ces modèles d’optimisation intègrent un modèle d’interférence SINR avec contrôle de puissance continue et variation de taux de transmission. Ils permettent, en particulier, de calculer une configuration optimale du réseau qui maximise la capacité ou minimise la consommation d’énergie. Ensuite, dans le troisième axe de recherche, nous étudions en détail le compromis entre la capacité du réseau et la consommation énergétique. Nous mettons en évidence plusieurs résultats d’ingénierie nécessaires pour un fonctionnement optimal d’un réseau maillé sans fil. Enfin, nous nous focalisons sur les réseaux cellulaires hétérogènes. Nous proposons des outils d’optimisation calculant une configuration optimale des stations de base qui maximise la capacité du réseau avec une consommation efficace d’énergie. Ensuite, afin d’économiser l’énergie, nous proposons une heuristique calculant un ordonnancement des stations et leur mise en mode d’endormissement partiel selon deux stratégies différentes, nommées LAFS et MAFS. / Wireless mesh networks (WMN) are a promising solution to support high data rate and increase the capacity provided to users, e.g. for meeting the requirements of mobile multimedia applications. However, the rapid growth of traffic load generated by the terminals is accompanied by an unsustainable increase of energy consumption, which becomes a hot societal and economical challenges. This thesis relates to the problem of the optimization of network capacity and energy consumption of wireless mesh networks. The network capacity is defined as the maximum achievable total traffic in the network per unit time. This thesis is divided into four main parts. First, we address the problem of improvement of the capacity of 802.11 wireless mesh networks. We highlight some insensible properties and deterministic factors of the capacity, while it is directly related to a bottleneck problem. Then, we propose a joint TDMA/CSMA scheduling strategy for solving the bottleneck issue in the network. Second, we focus on broadband wireless mesh networks based on time-frequency resource management. In order to get theoretical bounds on the network performances, we formulate optimization models based on linear programming and column generation algorithm. These models lead to compute an optimal offline configuration which maximizes the network capacity with low energy consumption. A realistic SINR model of the physical layer allows the nodes to perform continuous power control and use a discrete set of data rates. Third, we use the optimization models to provide practical engineering insights on WMN. We briefly study the tradeoff between network capacity and energy consumption using a realistic physical layer and SINR interference model. Finally, we focus on capacity and energy optimization for heterogeneous cellular networks. We develop, first, optimization tools to calculate an optimal configuration of the network that maximizes the network capacity with low energy consumption. We second propose a heuristic algorithm that calculates a scheduling and partial sleeping of base stations in two different strategies, called LAFS and MAFS.

<p>У докторској дисертацији су предложена два модела: модел за планирање испорука и агрегационо планирање производње и модел за прогнозу купчеве потражње у ланцу снабдевања у аутомобилској индустрији. Оба модела примењена су на студији случаја у предузећима два добављача из области аутомобилске индустрије у Републици Србији. Истраживање је показало применљивост предложених модела на практичним проблемима у присуству неизвесности и употребљивост њихових резултата у аутомобилској индустрији. Модели су показали боље резултате у односу на практичне податке у предузећима и у односу на основне стратегије за планирање производње и залиха које се користе у аутомобилској индустрији.</p> / <p>U doktorskoj disertaciji su predložena dva modela: model za planiranje isporuka i agregaciono planiranje proizvodnje i model za prognozu kupčeve potražnje u lancu snabdevanja u automobilskoj industriji. Oba modela primenjena su na studiji slučaja u preduzećima dva dobavljača iz oblasti automobilske industrije u Republici Srbiji. Istraživanje je pokazalo primenljivost predloženih modela na praktičnim problemima u prisustvu neizvesnosti i upotrebljivost njihovih rezultata u automobilskoj industriji. Modeli su pokazali bolje rezultate u odnosu na praktične podatke u preduzećima i u odnosu na osnovne strategije za planiranje proizvodnje i zaliha koje se koriste u automobilskoj industriji.</p> / <p>In doctoral dissertation are proposed two models: model for delivery planning and aggregate production planning and model for customer demand forecasting in supply chain in automotive industry. Both models are applied on the case study in enterprises of two suppliers from area of automotive industry in Republic of Serbia. The research shows applicability of proposed models on practital problems in the presence of uncertanty and usability of their results in automotive industry. Models have showed better results in regard to both the practical data in enterprises and a basic strategies for production planning and inventory planning which are used in automotive industry.</p>

The Master’s thesis deals with production scheduling in an industrial company. It uses the means of artificial intelligence to develop an appropriate production schedule in a generalized Flow-shop Programming problem. This problem can be solved by application which is a result of this thesis and was prepaired with use of the software Matlab 7.1 and its Genetic Algorithm and Direct Search toolbox. There is a part devoted to the use of advanced production systems (APS) and the concept of the operative production planning in praxis as well. The thesis pays attention to various optimization models in production scheduling and supply chain management too.