Dissertations / Theses on the topic 'Migration problem'
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Etchegaray, Christèle. "Modélisation mathématique et numérique de la migration cellulaire." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS428/document.
Full textCollective or individual cell displacements are essential in fundamental physiological processes (immune response, embryogenesis) as well as in pathological developments (tumor metastasis). The intracellular processes responsible for cell motion have a complex self-organized activity spanning different time and space scales. Highlighting general principles of migration is therefore a challenging task.In a first part, we build stochastic particular models of migration. To do so, we describe key intracellular processes as discrete in space by using stochastic population models. Then, by a renormalization in large population, infinitesimal size and accelerated dynamics, we obtain continuous stochastic equations for the dynamics of interest, allowing a relation between the intracellular dynamics and the macroscopic displacement.First, we study the case of a leukocyte carried by the blood flow and developing adhesive bonds with the artery wall, until an eventual stop. The binding dynamics is described by a stochastic Birth and Death with Immigration process. These bonds correspond to resistive forces to the motion. We obtain explicitly the mean stopping time of the cell.Then, we study the case of cell crawling, that happens by the formation of protrusions on the cell edge, that grow on the substrate and exert traction forces. We describe this dynamics by a structured population process, where the structure comes from the protrusions' orientations. The limiting continuous model can be analytically studied in the 1D migration case, and gives rise to a Fokker-Planck equation on the probability distribution for the protrusion density. For a stationary profile, we can show the existence of a dichotomy between a non motile state and a directional displacement state.In a second part, we build a deterministic minimal migration model in a discoïdal cell domain. We base our work on the idea such that the structures responsible for migration also reinforce cell polarisation, which favors in return a directional displacement. This positive feedback loop involves the convection of a molecular marker, whose inhomogeneous spatial repartition is characteristic of a polarised state.The model writes as a convection-diffusion problem for the marker's concentration, where the advection field is the velocity field of the Darcy fluid that describes the cytoskeleton. Its active character is carried by boundary terms, which makes the originality of the model.From the analytical point of vue, the 1D model shows a dichotomy depending on a critical mass for the marker. In the subcritical and critical cases, it is possible to show global existence of weak solutions, as well as a rate-explicit convergence of the solution towards the unique stationary profile, corresponding to a non-motile state. Above the critical mass, for intermediate values, we show the existence of two additional stationary solutions corresponding to polarised motile profiles. Moreover, for asymmetric enough initial profiles, we show the finite time apparition of a blowup.Studying a more complex model involving activation of the marker at the cell membrane permits to get rid of this singularity.From the numerical point of vue, numerical experiments are led in 2D either in finite volumes (Matlab) or finite elements (FreeFem++) discretizations. They allow to show both motile and non motile profiles. The effect of stochastic fluctuations in time and space are studied, leading to numerical simulations of cases of responses to an external signal, either chemical (chemotaxis) or mechanical (obstacles)
Keel, Thomas. "Ist Brain Drain ein Problem für Entwicklungsländer?" St. Gallen, 2005. http://www.biblio.unisg.ch/org/biblio/edoc.nsf/wwwDisplayIdentifier/02600765001/$FILE/02600765001.pdf.
Full textSacconi, Andrea. "Front-tracking finite element methods for a void electro-stress migration problem." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/34324.
Full textKayihan, Bahar. "Return Migration To Turkey: Identity Problem And Changes In The Concept Of Nation." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613503/index.pdf.
Full textBös, Mathias. "Migration als Problem offener Gesellschaften Globalisierung und sozialer Wandel in Westeuropa und Nordamerika /." Opladen : Leske + Budrich, 1997. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB8832586.
Full textSarkar, Dipak Kumar. "Refugee and Migration Problems in West Bengal: Society, Economy and Polity (1947-2000)." Thesis, University of North Bengal, 2016. http://ir.nbu.ac.in/handle/123456789/2834.
Full textHerrmann, Felix J., Peyman P. Moghaddam, and Rodney L. Kirlin. "Optimization strategies for sparseness- and continuity- enhanced imaging : Theory." European Association of Geoscientists & Engineers, 2005. http://hdl.handle.net/2429/500.
Full textDalemo, Henrik. "Problem vid migration av applikationer från Visual Basic 6 till Visual Basic .net vid användande av ett migrationsverktyg." Thesis, University of Skövde, School of Humanities and Informatics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-993.
Full textArbetet bygger på att de informationssystem som används idag men som blir allt äldre och därigenom inte klarar de krav som ställs på dem. Detta medför att informationssystemen måste migreras till modernare plattformar, då företagen dels inte klarar sig utan dess nuvarande funktionalitet och dels måste vidareutveckla systemen.
Detta arbete tar upp olika sätt som detta kan genomföras på och vilka problem som kan komma att uppstå när detta sker. För att kunna undersöka detta så genomfördes ett antal migrationer. Språken som migrationen kommer att ske mellan är Visual Basic 6 och Visual Basic .net. Migrationerna kommer att ske med hjälp av ett migrationsverktyg, samt ett ramverk som i arbetet skräddarsys för just arbetets typ av migrationer.
Det arbetet kommer fram till är att det sker problem vid användande av ett verktyg och även att det inte ger tillräckligt med respons på vad som gått snett under migrationerna.
Liebig, Thomas. "Immigration as a supply-side problem : the international competition for highly-skilled migrants /." [S.l. : s.n.], 2004. http://www.gbv.de/dms/zbw/470753544.pdf.
Full textCocher, Emmanuel. "Analyse de vitesse par migration itérative : vers une meilleure prise en compte des réflexions multiples." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEM016/document.
Full textActive seismic experiments are commonly used to recover a model of the P-wave propagation velocity in the subsurface. “Migration Velocity Analysis” techniques aim at deriving a smooth background velocity model controlling the kinematics of wave propagation. First, a reflectivity image is obtained by “migration” of observed data using a first estimate of the background velocity. This image depends on an additional “subsurface-offset” parameter allowing to assess the quality of the background velocity model with a focusing criterion and to correct it. However classical migration techniques do not provide a sufficiently accurate reflectivity image, leading to inconsistent velocity updates. In particular they do not take into account multiple reflections, usually regarded as noise and removed from the data before processing. Multiple removal is however a difficult step, and additional information contained in multiples is discarded.In this thesis, we propose to determine the reflectivity model by iterative migration before subsequent velocity analysis, leading to a nested optimisation procedure. Iterative migration yields accurate reflectivity image and extends naturally to the case of multiples. One of its disadvantages is the associated increased computational cost. To limit the number of iterations in the innerloop, a preconditioner based on a pseudo-inverse of the modelling operator is introduced. Another difficulty is the instability of the velocity update obtained with very close successive reflectivity models. We propose a modified approach, valid in the presence of multiples, and discussed through applications on 2D synthetic data sets
Andersson, My. "Who’s responsible? : A study of strategies for handling climate migration." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-387500.
Full textManuvie, Ritumbra. "Governance of climate change related migrations in Assam (India)." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31147.
Full textMkdad, Rudeina. "Problem representations of 'racisms' between people with migrant backgroundin online Swedish mass media." Thesis, Linköpings universitet, Institutionen för samhälls- och välfärdsstudier, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158105.
Full textBiallach, Hanane. "Optimization of VNF reconfiguration problem for 5G network slicing." Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2707.
Full textIn recent years, because of the unprecedented growth in the number of connected devices and mobile data, and the ongoing developments in technologies to address this enormous data demand, the fifth generation (5G) network has emerged. The forthcoming 5G architecture will be essentially based on Network Slicing (NS), which enables provide a flexible approach to realize the 5G vision. Thanks to the emerging Network Function Virtualization (NFV) concept, the network functions are decoupled from dedicated hardware devices and realized in the form of software. This offers more flexibility and agility in business operations. Despite the advantages it brings, NFV raises some technical challenges, the reconfiguration problem is one of them. This problem, which is NP-Hard, consists in reallocating the Virtual Network Functions (VNFs) to fit the network changes, by transforming the current state of deployed services, e.g., the current placement of Virtual Machines (VM) that host VNFs, to another state that updates providers’ objectives. This PhD thesis investigates how to reconfigure the VNFs by migrating them to an optimal state that could be computed in advance or free placement. In this thesis, we studied both cases while minimizing the service interruption duration and the VNF migration duration. We have proposed exact and approximate methods. Among the exact methods, we cite two ILP models. We also proposed two heuristic approaches, one based on column generation and the second using the concept of “arc set feedback”. The overall objective of this work is therefore to define and study the problem of VNF reconfiguration problem in the context of 5G network slicing, and propose mathematical models and efficient algorithms to solve the underlying optimization problems
Li, Yubing. "Analyse de vitesse par migration quantitative dans les domaines images et données pour l’imagerie sismique." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEM002/document.
Full textActive seismic experiments are widely used to characterize the structure of the subsurface. Migration Velocity Analysis techniques aim at recovering the background velocity model controlling the kinematics of wave propagation. The first step consists of obtaining the reflectivity images by migrating observed data in a given macro velocity model. The estimated model is then updated, assessing the quality of the background velocity model through the image coherency or focusing criteria. Classical migration techniques, however, do not provide a sufficiently accurate reflectivity image, leading to incorrect velocity updates. Recent investigations propose to couple the asymptotic inversion, which can remove migration artifacts in practice, to velocity analysis in the subsurface-offset domain for better robustness. This approach requires large memory and cannot be currently extended to 3D. In this thesis, I propose to transpose the strategy to the more conventional common-shot migration based velocity analysis. I analyze how the approach can deal with complex models, in particular with the presence of low velocity anomaly zones or discontinuous reflectivities. Additionally, it requires less memory than its counterpart in the subsurface-offset domain. I also propose to extend Inversion Velocity Analysis to the data-domain, leading to a more linearized inverse problem than classic waveform inversion. I establish formal links between data-fitting principle and image coherency criteria by comparing the new approach to other reflection-based waveform inversion techniques. The methodologies are developed and analyzed on 2D synthetic data sets
Yousef, Rose-Marie, and Johanna Nord. "Flyktingars problem och behov vid social integration : En systematisk litteraturstudie." Thesis, Mälardalens högskola, Akademin för hälsa, vård och välfärd, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-55225.
Full textBakgrund: Integrationspolitiken och invandringspolitiken redogör för flyktingarnas behov, skydd och integration i samhället. Integration -och invandringspolitiken har anordnat ett flertal åtgärder för att underlätta integrationen. Trots detta kvarstår mycket problematik kring implementeringen av en lyckad integrationspolitik för flyktingar. I Europa har det inrättats specifika lagar och riktlinjer som ska stötta flyktingarnas livsvillkor och rättigheter i det nya samhället. Problem: Flyktingfamiljer som består av barn, unga vuxna och vuxna kan bemöta svårigheter vid integrationen i ett nytt land. Det är viktigt att veta hur denna grupp ska bemötas och introduceras till samhället för att därmed kunna tillgodose flyktingarnas behov. Syfte: Syftet med detta arbete är att genom en systematisk litteraturstudie belysa vilka problem som kan uppstå för flyktingar och flyktingfamiljer vid den sociala integrationen i Europa. Metod: Systematisk litteraturstudie som är baserad på 12 vetenskapliga artiklar. Valda artiklar var: 7 kvalitativa artiklar, tre kvantitativa och två med mix-metod. Resultat: Språk, skola, uppehållstillstånd, ett bra bemötande av flyktingar och ett socialt nätverk visade sig vara betydande faktorer för främjandet av integrationsprocessen för flyktingarna. Slutsats: I det sociala arbetet är det viktigt att veta hur flyktingar ska bemötas för att inte försvåra deras integration i det nya samhället. Det är viktigt att flyktingarna inte känner sig exkluderade eller diskriminerade. Det är värdefullt att ha sympati för flyktingarna och förstå att ingen individ skulle frivilligt vilja lämna sitt hemland. Vidare forskning behövs för att kunna hitta nya förhållningssätt som kan främja flyktingfamiljernas integrationsprocess och en hållbar framtid.
Söderberg, Nora. "Climate-Induced Human Mobility in Policy : A Comparative Analysis of Problem Representations in Policy of Two Small-Island Cases." Thesis, Uppsala universitet, Statsvetenskapliga institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-402836.
Full textBös, Mathias [Verfasser], and Karl Otto [Akademischer Betreuer] Hondrich. "Migration als Problem offener Gesellschaften - Globalisierung und sozialer Wandel in Westeuropa und in Nordamerika / Mathias Bös ; Betreuer: Karl Otto Hondrich." Heidelberg : Universitätsbibliothek Heidelberg, 2000. http://d-nb.info/1177808765/34.
Full textPersson, Malin. "Asylum - not an EU problem? Qualitative analysis of the readmission agreements in the asylum and migration policy of the European Union." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22758.
Full textNordberg, Amanda. "Kärlek börjar aldrig med våld, men våld börjar alltid med kärlek – Destruktiva mansnormer eller ett ”importerat problem”? : En kvalitativ textanalys om Sverigedemokraternas förhållningssätt mot det ökade kvinnovåldet i Sverige." Thesis, Malmö universitet, Institutionen för globala politiska studier (GPS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-45783.
Full textVan, Le Wa. "Makten att tysta ner och lyfta upp "problem" med strategisk inramning : En kvalitativ studie om Socialdemokraternas inramning av migrations- och integrationsdiskursen efter migrationskrisen 2015." Thesis, Uppsala universitet, Statsvetenskapliga institutionen, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-345656.
Full textNguyen, Thi Minh. "Optimisation de l'allocation des ressources dans les réseaux d'infrastructure basés sur la virtualisation des fonctions réseau." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066626/document.
Full textNetwork service providers have to cope with the growing on-demand need from end-users as well as the diversity of usage. The "softwerization" and "loudification" of the network components offer a promising solution to achieve the agility necessary to dynamically match the servcice requirements with the level of resource consumption. Cloud-based solutions promises an economy of scale and simpler management. Virtualizing the many network appliances offers the flexibility to adapt to the varying service demand. This materializes with the deployment of Network Functions Virtualization (NFV) where Virtual Network Functions (VNFs) may be chained together to create network services. This dissertation studies the resource allocation problem in an NFV system for minimizing its cost under constraints on interconnectivity among VNFs, system resources, and service requirements. The main consideration is the reduction of the overall deployment cost while efficiently utilizing the available resources. In addition, a number of other important constraints are considered such as migration and congestion. Our first goal is to increase our understanding of the performance of an NFV system with respect to network functions placement and routing. We formalize the problem in a comprehensive maner taking into account a broad set of relevant parameters. The static (OFFLINE) and dynamic (ONLINE) cases are considered. We propose and analyze three heuristic algorithms: two for handling large dimensions of the OFFLINE problem and one designed to address the ONLINE scenario. The results show that our solution outperforms the state of the art with respect to critical performance index. We also evaluate the impact of migrating a set of running demands, and propose a simple migration technique for the dynamic system. We extend this work by proposing a simpler model to improve the performance of our solution. The second part of our work focuses on minimizing the resource utilization of an NFV system. The main distinctive point is that we can apply the model to a dynamic system with large instances. Moreover, we also provide an interesting method for generating some strong inequalities to improve the Linear Programming (LP) solving in a higher dimensional space. The obtained results are not only making the model easier but also can be used efficiently in other models. A third contribution focuses specifically on the routing problem in NFV. An important evolution of the users’ needs is represented by the dynamic on-demand access to network, vstorage and compute resources. Therefore, routing efficiently a demand across nodes handling the functions involved in a given service chain constitutes the a novel problem that we address in this last section. We provide an original formulation of this problem based on the construction of an expanded network. We derive the exact mathematical formulation and propose several approximate algorithms taking into account the main system’s parameters. We conclude by deriving some interesting insights both about the algorithms and the network performance. We finally conclude with our main findings and highlight many avenues for future work
Мартиненко, А. О. "Бідність як економічна проблема людства." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/11763.
Full textRocha, Francisco Matias da [Verfasser], Frank [Akademischer Betreuer] Nullmeier, and Michael [Akademischer Betreuer] Windzio. "Zum Problem der Land-Stadt-Migration im Nordosten Brasiliens - Die Gemeinden Tauá (CE) und Picos (PI) / Francisco Matias da Rocha. Gutachter: Frank Nullmeier ; Michael Windzio. Betreuer: Frank Nullmeier." Bremen : Staats- und Universitätsbibliothek Bremen, 2013. http://d-nb.info/1072225824/34.
Full textAhmadi, Forooshani Sayedhabibollah. "Examining the impact of trauma on young people's social adjustment: Developing a multi-dimensional intervention." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/225898/1/Sayedhabibollah_Ahmadi%20Forooshani_Thesis.pdf.
Full textCENTORRINO, SAMUELE. "Essays in Nonparamentric Estimation with Instrumental Variables." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/109031.
Full textCarcuz, Jerez Juan Ramon de Jesus. "An AVO method toward direct detection of lithologies combining P-P and P-S reflection data." Texas A&M University, 2003. http://hdl.handle.net/1969/38.
Full textСеменчук, Василь Миколайович, and Vasyl Semenchuk. "Методи та програмно-апаратні засоби оптимізаційних процесів на основі генетичних алгоритмів." Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/33351.
Full textThesis deals with the study of genetic algorithms as a way of optimization, their efficiency and complexity. The Travelling Salesman Problem was taken into consideration as it is very well studied, has effective ways of the decision, in order to compare with the received results. Also, one of the aims of this work is to study the propagation of genetic algorithms to a model with several interacting populations (migration and island). The MATLAB environment was taken as the main tool for practical research, as it has many built-in functions and toolbars for solving problems of genetic programming and their parallel execution.
1 Аналітична частина. 2 Теоретична частина. 3. Практична частина. Розв’язок задачі комівояжера з використанням можливостей пакета MATLAB. 4 Охорона праці та безпека в надзвичайних ситуаціях
Henseler, Joachim [Verfasser]. "Mobilität und Migration in der Einwanderungsgesellschaft / Joachim Henseler." Erfurt : Universität Erfurt, 2007. http://d-nb.info/1215980566/34.
Full textVaškelienė, Irena. "Pastarieji Lietuvos gyventojų migracijos pokyčiai ir grįžtamoji migracija." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20090120_140711-14690.
Full textThe subject of the master work is urgent reseach of the migration processes of Lithuania population. The streams, scales, and problems of Lithuania population migration have influence not only on sociodemographical changes of population but also on the economic, social and other policies of the government. Return migration is a new subject, as until recent the reseach on return migration reasons and the problems of migrants integration has not been done. The identification of its factors and problems is important. It is essencial in creating measures and putting them into practice, because it stimulates return migration of Lithuania population. The object of the study is the recent return migration of Lithuania population and its tendencies. The object is investigated trying to evaluate the streams, scales and reasons of Lithuania migration and the problems of return migrants integration. Moreover, the study presents some suggestions how to solve the problems of return migration. Fulfilling the assigments of the work some analysis on migration theories, Lithuania migration history, scientific as well as juridical and statistical literature, return migration reseach have been done. The factors and problems of return migration are determined and evaluated here. Also, the measures stimulating return migration are provided in the study. The hypotheses made in the work are that intensive migration streams allow the factor of return migration to form and social and family relations... [to full text]
Budathoki, Aakash. "Migration & Modernity." Thesis, Karlstad University, Faculty of Social and Life Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-2809.
Full textThe main objective of this essay is to analyze the challenges caused by today's modern phenomenon of change in our society and to discuss it in relationship to the process of migration. In doing so I focus on questions like, "what does it really mean when a person becomes a migrant and what does it mean to be the host country?" Becoming a migrant or a host country is a complex process which involves variety of challenges both for individuals and the locality. New inventions are made in the field of science and technology. Societies and social institutions are subjected to change and we undergo several changes or modifications to fit in to this changing system. This makes integration process more tedious and complex. I feel that the process of accepting and adopting begins from the very first moment in the new society. The one who comes in also brings in new cultural perspectives, new ideologies and beliefs. This establishes the background of plurality which has both positive and negative consequences.
I believe that every factor from bigger social institutions to minute incidents associated with an individual are of equal importance in understanding society as a whole. So I approach my research question here by considering both micro and macro theorists. I have also referred to migrations history of Sweden which provides general idea of types and mode of migration in the past few decades.
Forster, Emma. "Migration decision-making processes : an empirical investigation." Thesis, Edinburgh Napier University, 2000. http://researchrepository.napier.ac.uk/Output/3711.
Full textBudathoki, Aakash. "Modernity & Migration." Thesis, Karlstad University, Faculty of Social and Life Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-2807.
Full textSummery
The main objective of this essay is to analyze the challenges caused by today’s modern phenomenon of change in our society and to discuss it in relationship to the process of migration. In doing so I focus on questions like, “what does it really mean when a person becomes a migrant and what does it mean to be the host country?” Becoming a migrant or a host country is a complex process which involves variety of challenges both for individuals and the locality. New inventions are made in the field of science and technology. Societies and social institutions are subjected to change and we undergo several changes or modifications to fit in to this changing system. This makes intigration process more difficult and complex. I feel that the process of accepting and adopting begins from the very first moment in the new society. The one who comes in also brings in new cultural perspectives, new ideologies and beliefs. This establishes the background of plurality which has both positive and negative consequences.
I believe that every factor from bigger social institutions to minute incidents associated with an individual are of equal importance in understanding society as a whole. So I approach my research question here by considering both micro and macro theorists. I have also referred to migrations history of Sweden which provides general idea of types and mode of migration in the past few decades.
Melo, Márcio Daniel Tavares de. "Network virtualisation from an operator perspective." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/12876.
Full textNetwork virtualisation is seen as a promising approach to overcome the so-called “Internet impasse” and bring innovation back into the Internet, by allowing easier migration towards novel networking approaches as well as the coexistence of complementary network architectures on a shared infrastructure in a commercial context. Recently, the interest from the operators and mainstream industry in network virtualisation has grown quite significantly, as the potential benefits of virtualisation became clearer, both from an economical and an operational point of view. In the beginning, the concept has been mainly a research topic and has been materialized in small-scale testbeds and research network environments. This PhD Thesis aims to provide the network operator with a set of mechanisms and algorithms capable of managing and controlling virtual networks. To this end, we propose a framework that aims to allocate, monitor and control virtual resources in a centralized and efficient manner. In order to analyse the performance of the framework, we performed the implementation and evaluation on a small-scale testbed. To enable the operator to make an efficient allocation, in real-time, and on-demand, of virtual networks onto the substrate network, it is proposed a heuristic algorithm to perform the virtual network mapping. For the network operator to obtain the highest profit of the physical network, it is also proposed a mathematical formulation that aims to maximize the number of allocated virtual networks onto the physical network. Since the power consumption of the physical network is very significant in the operating costs, it is important to make the allocation of virtual networks in fewer physical resources and onto physical resources already active. To address this challenge, we propose a mathematical formulation that aims to minimize the energy consumption of the physical network without affecting the efficiency of the allocation of virtual networks. To minimize fragmentation of the physical network while increasing the revenue of the operator, it is extended the initial formulation to contemplate the re-optimization of previously mapped virtual networks, so that the operator has a better use of its physical infrastructure. It is also necessary to address the migration of virtual networks, either for reasons of load balancing or for reasons of imminent failure of physical resources, without affecting the proper functioning of the virtual network. To this end, we propose a method based on cloning techniques to perform the migration of virtual networks across the physical infrastructure, transparently, and without affecting the virtual network. In order to assess the resilience of virtual networks to physical network failures, while obtaining the optimal solution for the migration of virtual networks in case of imminent failure of physical resources, the mathematical formulation is extended to minimize the number of nodes migrated and the relocation of virtual links. In comparison with our optimization proposals, we found out that existing heuristics for mapping virtual networks have a poor performance. We also found that it is possible to minimize the energy consumption without penalizing the efficient allocation. By applying the re-optimization on the virtual networks, it has been shown that it is possible to obtain more free resources as well as having the physical resources better balanced. Finally, it was shown that virtual networks are quite resilient to failures on the physical network.
A virtualização de rede é vista como uma abordagem promissora para ultrapassar o “Impasse da Internet” e permitir inovação na Internet, possibilitando assim uma migração fácil para novas abordagens de redes, bem como a coexistência de arquiteturas de redes complementares numa infraestrutura compartilhada e em ambiente comercial. Recentemente tem crescido de forma bastante significativa o interesse pela virtualização de rede por parte dos operadores e dos grandes fabricantes, desde que os potenciais benefícios da virtualização se tornaram claros, tanto de ponto de vista económico como operacional. No início, o conceito foi versado pelo meio académico, onde foram realizadas provas de conceito de pequena escala, e em que a virtualização de rede foi considerada como forma de investigação de novos protocolos. Esta Tese de Doutoramento tem como objetivo geral dotar uma rede de operador de um conjunto de mecanismos e algoritmos capazes de gerir e controlar redes virtuais. Para este fim, é proposta uma framework que visa alocar, monitorizar e controlar recursos virtuais de uma forma centralizada e eficiente. De forma a analisar o desempenho da framework, procedeu-se à sua implementação e avaliação numa rede de pequena dimensão. De forma a permitir que se possa efetuar uma alocação eficiente, em tempo real, e a pedido, de redes virtuais numa rede física, é proposta uma heurística para efetuar o mapeamento na rede física. Para que o operador de rede possa rentabilizar ao máximo a sua infraestrutura de rede, é ainda proposta uma formulação matemática que, através de programação linear, visa maximizar o número de redes alocadas na infraestrutura de rede. Dado que o consumo energético de uma infraestrutura de rede começa a ter significância nos custos de operação, é importante que se faça a alocação das redes virtuais no menor número de recursos físicos e também em recursos físicos ativos. Para endereçar este desafio é proposta uma formulação matemática que visa minimizar o consumo energético da rede física sem afetar a eficiência da alocação de redes virtuais. Para minimizar a fragmentação da infraestrutura de rede e ao mesmo tempo aumentar as receitas do operador, é também estendida a formulação inicial para contemplar a re-otimização de redes virtuais previamente mapeadas, fazendo com que o operador tenha um melhor aproveitamento da sua infraestrutura física. Será ainda necessário endereçar a migração de redes virtuais, quer por motivos de balanceamento de carga, quer por motivos de falha iminente de recursos físicos, sem afetar o bom funcionamento da rede virtual. Para este fim, é proposto um método baseado em técnicas de clonagem, para efetuar a migração de redes virtuais entre recursos da infraestrutura física de forma transparente e sem impacto para a rede virtual. De forma a avaliar a resiliência das redes virtuais a falhas na rede física, e ao mesmo tempo obter a solução ótima de migração de redes virtuais em caso de falha iminente dos recursos físicos, a formulação matemática é estendida para minimizar o número de nós migrados em simultâneo com a realocação de ligações virtuais. Em comparação com as nossas propostas de otimização verificou-se que as heurísticas existentes para mapeamento de redes virtuais têm um desempenho muito baixo. Verificou-se ainda que é possível efetuar a redução do consumo energético sem a penalização da alocação eficiente. Com a re-otimização das redes virtuais mostrou-se que é possível obter mais recursos livres, assim como obter uma melhor distribuição dos recursos. Por último, demonstrou-se que as redes virtuais são bastante resilientes a falhas na rede física.
Moss, Philip John. "The migration and racialisation of doctors from the Indian subcontinent." Thesis, University of Warwick, 1991. http://wrap.warwick.ac.uk/71953/.
Full textRivinoja, Peter. "Migration problems of Atlantic salmon (Salmo salar L.) in flow regulated rivers /." Umeå : Dept. of Aquaculture, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/2005114.pdf.
Full textHeinzmann, Cornelia [Verfasser]. "Mobilitätspartnerschaften und zirkuläre Migration zwischen der EU und Afrika / Cornelia Heinzmann." Frankfurt : Peter Lang GmbH, Internationaler Verlag der Wissenschaften, 2015. http://d-nb.info/1080458719/34.
Full textBalta, Venetia. "Problemes d'identite dans la litterature neo-hellenique de la migration." Université Marc Bloch (Strasbourg) (1971-2008), 1996. http://www.theses.fr/1996STR20080.
Full textThe purpose of this dissertation is to examine the main identity problems of the greek literature of migration in prose which was created in europe. The first part contains main theoretical elements of the identity notion in psychology and sociology as well as the total number of the literary texts collected and studied during the research. The second part is devoted to the systematic study of a limited number of literary texts belonging in two different periods (19th century/ post-war period). These are texts of nine authors of a great variety. The third part is devoted to the elaboration on certain suppositions put forward during the analysis of the texts. In this cese the objective is to search the main traits of the greek migration literature in prose: the interdependence of the issue of migration and the problematic of identity, the function of space and time facts, the role of characters in the development of the plot etc
Handke, Daniela [Verfasser], and Karin [Akademischer Betreuer] Böllert. "Frühe Hilfen und Migration : Familien mit Migrationshintergrund im Kontext Früher Hilfen / Daniela Handke ; Betreuer: Karin Böllert." Münster : Universitäts- und Landesbibliothek Münster, 2020. http://d-nb.info/1211003116/34.
Full textAziz, Karima. "Migration aspirations and experiences of female Polish migrant workers in the UK." Thesis, London Metropolitan University, 2018. http://repository.londonmet.ac.uk/3029/.
Full textPopova, MARINA. "Lietuvoje gyvenančių trečiųjų šalių piliečių socialinės integracijos problema socialinio darbo kontekste." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20120125_144447-62305.
Full textM. Popova. The Problem of Social Integration of Third-Countries Citizens in the Context of Social Work in Lithuania. Final thesis of master’s degree study programme in social work. Supervisor prof. dr. E.Aciene, Klaipeda university: Klaipeda, 2011. – 106 pages. Social integration of third world country citizens living in Lithuania is one of the key issues of today’s society as considering a trend of decrease in numbers, next year the growth of immigration to Lithuania is possible and necessary. Integration of immigrants is very important for both social linkage and economic development. So that immigrants could feel a part of society we must treat them honestly and provide them with means necessary to become members of our society. Integration is a continual, two-way process based on mutual rights and duties of both immigrants and Lithuanian society. Having analyzed scientific literature, a research object is an evaluation of third world country citizens’ problem of social integration. Aim of research – to analyze a problem of social integration of citizens of third world countries living in Lithuania. Method of research: analysis of scientific literature, quantitative research applying questionnaire and qualitative research applying interview. Analyzing the firs goal – a theoretic discourse of migration rating theories of world migration, trends of world migration, theories of international migration and immigration challenge for Lithuania were studied. The second goal... [to full text]
Specht, Johannes [Verfasser]. "Sicherheit, Migration und Menschenrechte in Mexikos Grenzräumen : Eine Untersuchung der staatlichen mexikanischen „Betagruppen zum Schutz der Migrierenden“ / Johannes Specht." Berlin : Freie Universität Berlin, 2015. http://d-nb.info/107386880X/34.
Full textCulliney, Martin. "Going nowhere? : rural youth employment, social capital and migration in Britain." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4624/.
Full textSveinsson, Kjartan Páll. "Swimming against the tide : trajectories and experiences of migration amongst Nigerian doctors in England." Thesis, London School of Economics and Political Science (University of London), 2015. http://etheses.lse.ac.uk/3279/.
Full textSanson, Esther Mary. "The Chinese Communist Party and China's Rural Problems." Thesis, University of Canterbury. Languages and Cultures, 2008. http://hdl.handle.net/10092/1903.
Full textKovner, Nimrod Z. "Migration in a warming world : on the responsibility and obligations of states towards climate change immigrants." Thesis, London School of Economics and Political Science (University of London), 2017. http://etheses.lse.ac.uk/3582/.
Full textHenning, Karla [Verfasser], Stephan [Akademischer Betreuer] Klasen, Michael [Gutachter] Grimm, and Marcela [Gutachter] Ibanez. "Essays on Social Preferences in the Contexts of Donations, Migration, Religious Worship and Insurance / Karla Henning ; Gutachter: Michael Grimm, Marcela Ibanez ; Betreuer: Stephan Klasen." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://d-nb.info/1177361817/34.
Full textBrovia, Cristina. "Migrants de saison : les camps de travailleurs agricoles étrangers comme problème public : le cas de Saluzzo (Italie)." Thesis, Paris 1, 2018. http://www.theses.fr/2018PA01D041.
Full textThis thesis examines how the presence of seasonal migrant workers’ camps in intensive agricultural areas in Northern Italy is framed and addressed as a public problem. It draws on fieldwork carried out between 2013 and 2017 in the rural area of Saluzzo (Piedmont). The qualitative methodology includes sociological interviews, participant observation with organizations and in migrants’ camps, and the analysis of the local press. The thesis aims to understand how the presence of seasonal migrants is defined and constructed by a range of actors with divergent interests. In particular, it examines a set of public mobilisations and counter-mobilisations, analysing how they have influenced the actions undertaken to solve “the problem” of migrants’ camps in the Saluzzo area. The main argument is that the problem has been progressively constructed around the temporariness of migrants’ presence in the area. This has justified the setting up of temporary and precarious reception systems, leading to the spatial and temporal confinement of the migrants. In particular, the thesis shows how the organisation of institutionalised and controlled camps, managed by a major humanitarian organization and benefiting from wide public consensus, resulted in a decrease of conflict around seasonal labour migration, and to the sidelining of the issue in the political debate. Contributing to literature on migration in the field of political sociology, the monograph represents a timely intervention in highly topical debates on the politics of migrants’ presence in the Italian society
Questa ricerca riguarda i processi di costruzione di un problema pubblico ad un livello locale, partendo da diverse problematiche scaturite intorno ad accampamenti di lavoratori migranti stagionali in alcune zone di agricoltura intensiva in Italia. Lo studio è principalmente basato su una ricerca empirica svolta tra il 2013 e il 2017 nell’area rurale di Saluzzo (Piemonte) utilizzando una metodologia qualitativa che comprende interviste sociologiche, osservazione partecipante con associazioni militanti e all’interno degli accampamenti di migranti e l’analisi di articoli della stampa locale. L’obiettivo principale era quello di studiare il modo in cui la presenza di lavoratori migranti, in questo contesto specifico, è percepita come un problema pubblico, in che modo quest’ultimo è definito e costruito da una serie di attori animati da interessi contrastanti in un gioco di mobilitazioni e contro-mobilitazioni, poi di analizzare le conseguenze di tali dinamiche sulle azioni messe in atto per la risoluzione del problema. La tesi dimostra in particolare che la costruzione del problema si è progressivamente focalizzata sul carattere temporaneo della presenza dei migranti, a scapito di altri possibili frame, andando a giustificare la messa in atto di dispositivi di accoglienza precari e provvisori, finalizzati al confinamento spaziale e temporale dei migranti. Inoltre, l’instaurazione di campi sempre più istituzionalizzati e controllati, gestiti da un’organizzazione umanitaria riconosciuta, ha favorito la riduzione dei conflitti intorno alla questione e un accantonamento del problema sul piano del dibattito politico pubblico. Più in generale, questo lavoro, analizzando una questione inerente a dinamiche migratorie attraverso il prisma della sociologia politica, invita ad una più ampia riflessione sul trattamento politico dei migranti e sulla costruzione collettiva della posizione che essi occupano all’interno della società italiana di oggi
Kosygina, Larisa Vladimirovna. "The Russian migration regime and migrants' experiences : the case of non-Russian nationals from former Soviet republics." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/650/.
Full textChauris, Hervé. "Analyse de vitesse par migration pour l'imagerie des structures complexes en sismique réflexion." Paris, ENMP, 2000. http://www.theses.fr/2000ENMP1055.
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