Optimisation par essaim particulaire (adaptation de tribes à l'optimisation multiobjectif)

Dans le cadre de l'optimisation multiobjectif, les métaheuristiques sont reconnues pour être des méthodes performantes mais elles ne rencontrent qu'un succès modéré dans le monde de l'industrie. Dans un milieu où seule la performance compte, l'aspect stochastique des métaheuristiques semble encore être un obstacle difficile à franchir pour les décisionnaires. Il est donc important que les chercheurs de la communauté portent un effort tout particulier sur la facilité de prise en main des algorithmes. Plus les algorithmes seront faciles d'accès pour les utilisateurs novices, plus l'utilisation de ceux-ci pourra se répandre. Parmi les améliorations possibles, la réduction du nombre de paramètres des algorithmes apparaît comme un enjeu majeur. En effet, les métaheuristiques sont fortement dépendantes de leur jeu de paramètres. Dans ce cadre se situe l'apport majeur de TRIBES, un algorithme mono-objectif d'Optimisation par Essaim Particulaire (OEP) qui fonctionne automatiquement,sans paramètres. Il a été mis au point par Maurice Clerc. En fait, le fonctionnement de l'OEP nécessite la manipulation de plusieurs paramètres. De ce fait, TRIBES évite l'effort de les régler (taille de l'essaim, vitesse maximale, facteur d'inertie, etc.).Nous proposons dans cette thèse une adaptation de TRIBES à l'optimisation multiobjectif. L'objectif est d'obtenir un algorithme d'optimisation par essaim particulaire multiobjectif sans paramètres de contrôle. Nous reprenons les principaux mécanismes de TRIBES auxquels sont ajoutés de nouveaux mécanismes destinés à traiter des problèmes multiobjectif. Après les expérimentations, nous avons constaté, que TRIBES-Multiobjectif est moins compétitif par rapport aux algorithmes de référence dans la littérature. Ceci peut être expliqué par la stagnation prématurée de l'essaim. Pour remédier à ces problèmes, nous avons proposé l'hybridation entre TRIBES-Multiobjectif et un algorithme de recherche locale, à savoir le recuit simulé et la recherche tabou. L'idée était d'améliorer la capacité d'exploitation deTRIBES-Multiobjectif. Nos algorithmes ont été finalement appliqués sur des problèmes de dimensionnement des transistors dans les circuits analogiquesMeta-heuristics are recognized to be successful to deal with multiobjective optimization problems but still with limited success in engineering fields. In an environment where only the performance counts, the stochastic aspect of meta-heuristics again seems to be a difficult obstacle to cross for the decision-makers. It is, thus, important that the researchers of the community concern a quite particular effort to ease the handling of those algorithms. The more the algorithms will be easily accessible for the novices, the more the use of these algorithms can spread. Among the possible improvements, reducing the number of parameters is considered as the most challenging one. In fact, the performance of meta-heuristics is strongly dependent on their parameters values. TRIBES presents an attempt to remedy this problem. In fact, it is a particle swarm optimization (PSO) algorithm that works in an autonomous way. It was proposed by Maurice Clerc. Indeed, like every other meta-heuristic, PSO requires many parameters to be fitted every time a new problem is considered. The major contribution of TRIBES is to avoid the effort of fitting them. We propose, in this thesis, an adaptation of TRIBES to the multiobjective optimization. Our aim is to conceive a competitive PSO algorithm free of parameters. We consider the main mechanisms of TRIBES to which are added new mechanisms intended to handle multiobjective problems. After the experimentations, we noticed that Multiobjective-TRIBESis not competitive compared to other multiobjective algorithms representative of the state of art. It can be explained by the premature stagnation of the swarm. To remedy these problems, we proposed the hybridization between Multiobjective-TRIBES and local search algorithms such as simulated annealing and tabu search. The idea behind the hybridization was to improve the capacity of exploitation of Multiobjective-TRIBES. Our algorithms were finally applied to sizing analogical circuits' problemsPARIS-EST-Université (770839901) / SudocSudocFranceF

Facilitating the Use of Optimisation in the Aerodynamic Design of Axial Compressors

There is commercial pressure to design axial compressors exhibiting high levels of performance more quickly. This is despite the performance of these machines approaching an asymptote in recent years, with further gains becoming increasingly difficult to achieve. One tool that can be used to help is optimisation, effectively harnessing the speed of computational analysis to accelerate the design process and unlock additional performance improvements. The greatest potential for optimisation exists at the preliminary design stage, however, current methodologies struggle when applied at this early point in the design process due to inadequate problem formulations, an inability to fulfil the role of enhancing designer understanding and a lack of high-fidelity analysis due to computational cost. The goal of this thesis is to facilitate the use of optimisation in the preliminary aerodynamic design of axial compressors by developing an improved methodology that overcomes these limitations. The multiple dominance relations (MDR) formulation enables a larger number of performance parameters to be incorporated in a way that accurately reflects the desires of the designer. This is implemented within a Tabu Search (TS) that is capable of providing interpretable design development information to enhance designer understanding. The combined MDRTS algorithm, overcoming the limitations associated with formulation and understanding, outperforms existing methods when applied to analytic, aerofoil and six-stage axial compressor test cases, generating computational savings of up to 80%. Multi-fidelity techniques are used to accelerate the search by conducting analysis on a "need-to-know'' basis. Computational savings of over 70% are observed compared to the single-fidelity version of the algorithm across the analytic, aerofoil and six-stage axial compressor test cases, enabling high-fidelity analysis to be employed in a computationally efficient manner. The resultant methodology represents a novel and inherently flexible multi-level multi-fidelity optimisation technique. Application to an N-stage axial compressor test case, in which the optimiser is given control over the number of stages in the machine, demonstrates the capabilities of the accelerated MDRTS approach. The complex design space is effectively navigated, generating computational savings of over 90% compared to existing methodologies and producing designs that are more likely to be of interest to the designer. Interpretable design development information is also provided for this problem to enhance designer understanding. These results show that the improved methodology successfully facilitates the use of optimisation in the preliminary aerodynamic design of axial compressors, overcoming the problems associated with formulation, understanding and speed that limit existing approaches

A Framework for Hyper-Heuristic Optimisation of Conceptual Aircraft Structural Designs

Conceptual aircraft structural design concerns the generation of an airframe that will provide sufficient strength under the loads encountered during the operation of the aircraft. In providing such strength, the airframe greatly contributes to the mass of the vehicle, where an excessively heavy design can penalise the performance and cost of the aircraft. Structural mass optimisation aims to minimise the airframe weight whilst maintaining adequate resistance to load. The traditional approach to such optimisation applies a single optimisation technique within a static process, which prevents adaptation of the optimisation process to react to changes in the problem. Hyper-heuristic optimisation is an evolving field of research wherein the optimisation process is evaluated and modified in an attempt to improve its performance, and thus the quality of solutions generated. Due to its relative infancy, hyper-heuristics have not been applied to the problem of aircraft structural design optimisation. It is the thesis of this research that hyper-heuristics can be employed within a framework to improve the quality of airframe designs generated without incurring additional computational cost. A framework has been developed to perform hyper-heuristic structural optimisation of a conceptual aircraft design. Four aspects of hyper-heuristics are included within the framework to promote improved process performance and subsequent solution quality. These aspects select multiple optimisation techniques to apply to the problem, analyse the solution space neighbouring good designs and adapt the process based on its performance. The framework has been evaluated through its implementation as a purpose-built computational tool called AStrO. The results of this evaluation have shown that significantly lighter airframe designs can be generated using hyper-heuristics than are obtainable by traditional optimisation approaches. Moreover, this is possible without penalising airframe strength or necessarily increasing computational costs. Furthermore, improvements are possible over the existing aircraft designs currently in production and operation

Trends and challenges for sustainable marine resource management for rural Solomon Islanders

Much has been claimed about the positive benefits of the customary marine tenure (CMT) system in the South Pacific and its implications for resource management. In Solomon Islands the premise of effective community-based resource management (CBRM) as a contemporary management tool, rests to a great degree on CMT, but does CMT still provide a sufficiently strong foundation to support this premise? This research examines the social and environmental characteristics of two rural Solomon Islands coastal communities that have a long history in customary marine tenure; one with a strong chiefly system and the other one with a weaker chiefly system. The research gains insight into and an understanding of the experiences and lives of the villagers, given current debates on the need to address and move forward with the concept of CBRM with regards to the sustainability issues that they are currently confronting. Using primarily qualitative methodologies the study focused on how marine resources are perceived and valued by different members of the community. The findings suggest that in communities where a common agreement on CMT no longer exists there is a significant challenge to stakeholders in attaining the goal of sustainably managed coastal marine resources through community based approaches. This challenge needs to be accounted for on a case by case basis as part of CBRM facilitation processes. While this research may true for much of Solomon Islands, the case studies have revealed that although the villages are made up of families who are closely related they are not unified as a whole. Study findings suggest that the people retain a lingering vision of a small, integrated community but have failed to grasp how their differences as a community have affected their resource management outcomes. The present day communities are affected by many outside factors that did not exist when traditional management systems were evolving. These factors bring management challenges for which traditional arrangements were not designed to cope and thus many have severely destabilising effects on the performance of traditional systems

Application of PSO for optimization of power systems under uncertainty

The primary objective of this dissertation is to develop a black box optimization tool. The algorithm should be able to solve complex nonlinear, multimodal, discontinuous and mixed-integer power system optimization problems without any model reduction. Although there are many computational intelligence (CI) based algorithms which can handle these problems, they require intense human intervention in the form of parameter tuning, selection of a suitable algorithm for a given problem etc. The idea here is to develop an algorithm that works relatively well on a variety of problems with minimum human effort. An adaptive particle swarm optimization algorithm (PSO) is presented in this thesis. The algorithm has special features like adaptive swarm size, parameter free update strategies, progressive neighbourhood topologies, self learning parameter free penalty approach etc. The most significant optimization task in the power system operation is the scheduling of various generation resources (Unit Commitment, UC). The current practice used in UC modelling is the binary approach. This modelling results in a high dimension problem. This in turn leads to increased computational effort and decreased efficiency of the algorithm. A duty cycle based modelling proposed in this thesis results in 80 percent reduction in the problem dimension. The stern uptime and downtime requirements are also included in the modelling. Therefore, the search process mostly starts in a feasible solution space. From the investigations on a benchmark problem, it was found that the new modelling results in high quality solutions along with improved convergence. The final focus of this thesis is to investigate the impact of unpredictable nature of demand and renewable generation on the power system operation. These quantities should be treated as a stochastic processes evolving over time. A new PSO based uncertainty modelling technique is used to abolish the restrictions imposed by the conventional modelling algorithms. The stochastic models are able to incorporate the information regarding the uncertainties and generate day ahead UC schedule that are optimal to not just the forecasted scenario for the demand and renewable generation in feed but also to all possible set of scenarios. These models will assist the operator to plan the operation of the power system considering the stochastic nature of the uncertainties. The power system can therefore optimally handle huge penetration of renewable generation to provide economic operation maintaining the same reliability as it was before the introduction of uncertainty

Structure, Gender, Tribalism, And Workplace Power In Libya

The study examines the nature of workplace power in a Libyan oil company and how is power distributed, managed, and maintained within the structure of this workplace. I also examine how gender and tribal identities affect who has power in the workplace setting. I also look at the types of decisions workers have control over, depending on their rank and status within the organization, time with company, gender and tribal identity. In this proposal, I argue that workplace power is not only about decision making within the company, but it also mirrors larger social and political inequalities in the society at large. The goal of this quantitative study is to examine employee authority and influence within workplace. Specifically, the research objectives are: 1) to describe the standardization of workplace power regarding structural characteristics, as defined by formalization, centralization, and specialization; 2) to investigate the relationship between gender and the ability to make decisions and influence decision making; 3) to examine the relationship between tribalism identification and the ability to make decisions and influence decision making, and 4) to explore work commitment and the ability to make decisions and influence decision making. This study intends to determine which variables explain the most variance in the distribution of workplace power. Data was gathered using a self-administered questionnaire given to a disproportionate stratified random sampling of employees working at Azzawiya Oil Refining Company. The findings show that power is unevenly distributed by gender and women’s power in the workplace remains constrained. Also, workplace power affected by tribal identities. Workers who belong to a powerful tribe can be involved in the process of decision making. Keywords— , , , workplace powe

WARC Thunderbird, Volume 6

1980's WARC (Washington Archeological Research Center) was an experiment in communitarianism for Northwest Archaeology--and it did WARC (Work). This is Volume 6 of our News Bulletin, the WARC Thunderbird, with Issues 1-9, 1985-1986. The WARC Thunderbird provided a platform for communications across the region and contains a wealth of information about this formative period of Archaeology in Washington State. The Washington Archaeological Research Center was established in 1972 at Washington State University as a contract clearinghouse, mainly for Federal and State funded archaeological field projects, with the goal of assigning field projects throughout the state through a Scientific Committee with archaeologists at the six four-year universities and colleges. The founder of this phase of WARC’s operations was Dr. Richard D. Daugherty, Director, and most field projects were coordinated by his Assistant Harvey Rice. In 1980 the WARC Administrative Board, the Graduate Deans at the six four-year Washington colleges, and the Scientific Committee, felt each institution should be allowed to take their own directions as archaeological field contract programs, and decided to keep the general framework of WARC intact, to coordinate and maintain, with the State Office of Archaeology and Historic Preservation (OAHP), the State’s site records, contract/research reports library, and facilitate communications and coordination of general records-based research at the six WARC institution. Dr. Dale R. Croes was assigned Acting Director (a 1/2-time position) and he recruited Steven Hackenberger as his able Assistant Director. This revised structure continued to bring together the WARC Administrative Board, the Scientific Committee and the establishment of a broad Advisory Council representing private contract archaeologists; professional archaeologists from Oregon, Idaho, and British Columbia, Canada; Native American Representatives; Federal/State agencies; and Archaeological/Historical Societies. In many ways it was an effort to work together, using our limited resources, to promote archaeological interests (especially digitizing, standardizing and updating our paper-based archaeological site forms)—a coordinating of our discipline, in a form of communitarianism, based on the idea that those involved in archaeology were essentially cooperative (“good”) people who wanted to work together for our common goals

Pimatisiwin : indigenous knowledge systems, our time has come

This naturalistic inquiry explored the contributions of Indigenous Knowledge to higher learning with the intention of improving life for all Indigenous Peoples. An interdisciplinary approach was used to examine the participation of Indigenous Peoples through the disciplines of native studies, education, and health. Critical theory was used by including feminists of color, post colonialists and other scholars who examine cultural, political and intellectual domination as a means of social control.Indigenous peoples represent approximately seven percent of the world’s population. They have developed knowledges that reflect their circumstances, environments and challenges and that meet the needs of peoples who for the most part have not been industrialized. Indigenous knowledges reflect the many aspects of life that make up community comprising agriculture, arts, medicines, architecture, weather and other aspects of culture such as stories, music, dance and languages. Indigenous scholars and community-based groups are integrating their knowledge into higher learning and within other educational centers. This dissertation contains our stories.Storytelling was a central research tool throughout this dissertation employed to gather stories from the regions of South Africa, the Pacific, and North America who have long been active in the field of education as well as community activism. Using respectful research that paralleled the ideals of participatory action research, the overarching research question originated from the communities of the Indigenous participants. Through a polyphonic text that presents multiple voices of participants, meanings garnered through conversational interviews, focused participant observation are juxtaposed with meaning-making by the storytelling of the researcher. Critical theory problematized and critically analyzed insights into Indigenous participation within the academic community.The findings for this study suggest the range of work that is to be done and as well it shares stories of how this is being undertaken in several regions in our extended global community. The participants were interested and encouraged to participate collaboratively in the production of a document which asked how community based and higher learning institutes could contribute to the quality of life for Indigenous peoples and entire communities

Management, Technology and Learning for Individuals, Organisations and Society in Turbulent Environments

This book presents the collection of fifty papers which were presented in the Second International Conference on BUSINESS SUSTAINABILITY 2011 - Management, Technology and Learning for Individuals, Organisations and Society in Turbulent Environments , held in Póvoa de Varzim, Portugal, from 22ndto 24thof June, 2011.The main motive of the meeting was growing awareness of the importance of the sustainability issue. This importance had emerged from the growing uncertainty of the market behaviour that leads to the characterization of the market, i.e. environment, as turbulent. Actually, the characterization of the environment as uncertain and turbulent reflects the fact that the traditional technocratic and/or socio-technical approaches cannot effectively and efficiently lead with the present situation. In other words, the rise of the sustainability issue means the quest for new instruments to deal with uncertainty and/or turbulence. The sustainability issue has a complex nature and solutions are sought in a wide range of domains and instruments to achieve and manage it. The domains range from environmental sustainability (referring to natural environment) through organisational and business sustainability towards social sustainability. Concerning the instruments for sustainability, they range from traditional engineering and management methodologies towards “soft” instruments such as knowledge, learning, and creativity. The papers in this book address virtually whole sustainability problems space in a greater or lesser extent. However, although the uncertainty and/or turbulence, or in other words the dynamic properties, come from coupling of management, technology, learning, individuals, organisations and society, meaning that everything is at the same time effect and cause, we wanted to put the emphasis on business with the intention to address primarily companies and their businesses. Due to this reason, the main title of the book is “Business Sustainability 2.0” but with the approach of coupling Management, Technology and Learning for individuals, organisations and society in Turbulent Environments. Also, the notation“2.0” is to promote the publication as a step further from our previous publication – “Business Sustainability I” – as would be for a new version of software. Concerning the Second International Conference on BUSINESS SUSTAINABILITY, its particularity was that it had served primarily as a learning environment in which the papers published in this book were the ground for further individual and collective growth in understanding and perception of sustainability and capacity for building new instruments for business sustainability. In that respect, the methodology of the conference work was basically dialogical, meaning promoting dialog on the papers, but also including formal paper presentations. In this way, the conference presented a rich space for satisfying different authors’ and participants’ needs. Additionally, promoting the widest and global learning environment and participation, in accordance with the Conference's assumed mission to promote Proactive Generative Collaborative Learning, the Conference Organisation shares/puts open to the community the papers presented in this book, as well as the papers presented on the previous Conference(s). These papers can be accessed from the conference webpage (http://labve.dps.uminho.pt/bs11). In these terms, this book could also be understood as a complementary instrument to the Conference authors’ and participants’, but also to the wider readerships’ interested in the sustainability issues. The book brought together 107 authors from 11 countries, namely from Australia, Belgium, Brazil, Canada, France, Germany, Italy, Portugal, Serbia, Switzerland, and United States of America. The authors “ranged” from senior and renowned scientists to young researchers providing a rich and learning environment. At the end, the editors hope, and would like, that this book to be useful, meeting the expectation of the authors and wider readership and serving for enhancing the individual and collective learning, and to incentive further scientific development and creation of new papers. Also, the editors would use this opportunity to announce the intention to continue with new editions of the conference and subsequent editions of accompanying books on the subject of BUSINESS SUSTAINABILITY, the third of which is planned for year 2013.info:eu-repo/semantics/publishedVersio