Ce travail de thèse a pour objectif de développer une nouvelle technologie afin de fournir une solution bas coût et simple d’utilisation pour les raccordements de fibres optiques entre elles. Cette technologie fibre-fibre pourra être étendue à des raccordements fibre-composant d’optique intégrée.Cette nouvelle technique est basée sur la photo-polymérisation d’une solution chimique, utilisée pour reconstruire une structure d’indice guidante entre les deux éléments de guides optiques à connecter. Pour mettre au point cette technologie nous nous sommes concentrés sur la réalisation d’un raccordement de deux fibres optiques.Après une analyse des technologies existantes et des causes de pertes lors des raccordements entre deux fibres optiques, nous détaillons les différentes solutions de photo-polymères employés. Nous abordons le fonctionnement de la polymérisation radicalaire, ainsi que la composition des solutions utilisées, puis nous présentons les performances attendues. Pour cela nous utilisons un environnement de simulation FDTD (Finite Différence Time Domaine), ce qui nous permet de mettre en évidence que cette technique de raccordement a le potentiel d’être équivalente aux techniques employées dans les télécoms de nos jours. Toujours dans l’objectif d’étudier ce nouveau type de connexion, et d’en optimiser les performances, nous avons mis en place une méthode d’analyse de la répartition de l’indice de réfraction au cœur même des connexions polymère. Pour cela nous employons une méthode de tomographie interférométrique, que nous avons adapté à la mesure de fibre et de petits objets en extrémité de fibre. Cette nouvelle technique d’analyse, développée en partenariat avec le département mécatronique de l’Université de Varsovie, permet de reconstruire une cartographie en trois dimensions de la répartition de l’indice de réfraction. Nous avons ainsi pu analyser des connexions polymères réalisées avec différentes solutions photochimiques, et observer les défauts d’homogénéité d'indice. Ceci dans le but de reproduire le plus parfaitement possible la structure d’indice des fibres optiques, et par là même réduire au maximum les pertes optiques au niveau de la connexion. A l’aide de ces analyses, nous sommes arrivés à l’application final de cette technique pour le marché des Télécommunication optiques : Nous avons ainsi réaliser des prototypes de raccordement de deux fibres optiques, ainsi que de tous les outils nécessaires à leur réalisation sur le terrain, et avons démontré que leur performances étaient équivalente aux produits aujourd’hui présent sur le marché. / The aim of this thesis is to develop a new technology providing a low cost and “easy to use “solution for interconnections of optical fibers. This fiber-optic technology can be extended to connections between fiber and integrated optical component. This new technique is based on photo-polymerization of a chemical solution used to rebuild a guiding index structure between two elements of optical waveguides. With the aim to study this new type of connection, and optimize it’s performances, we have implemented a method for analysing the distribution of the refractive index within the polymer connexions. For this we use an interferometric tomography method, that we adapted to measure the fiber and small items at fiber end. This new analysis technique, developed in partnership with the Department of Mechatronics of Warsaw University, allows to reconstruct a three-dimensional mapping of the refractive index distribution. We are able to analyse polymers connections made with different photochemical solutions and observe defects in the index homogeneity. This is done in order to replicate as possible the index structure of optical fibers, and thereby minimize optical losses at connection. Using these analysis, we set to the final application of this technique, at the optical Telecommunications market: we have developed prototypes of splicing between two optical fibers, as well as designed all necessary tools for their implementation in the field, and we have demonstrated that their performance is equivalent to products now available on the market.

The scale of the sustainability crisis is mounting exponentially as human development pushes the socio-ecological system closer to its limits. 12 to 18 year olds, who are in a formative life stage, are critical stakeholders in the success of addressing this sustainability challenge. This study explores the role of nature camps as powerful platforms for empowering young people towards sustainability. It begins by creating a conceptual framework to identify, define and design youth empowerment towards sustainability (YES). This is then used to identify relevant current practices and activities in the field through qualitative interviews with nature camp practitioners. A focus group is held to trial the YES Framework and collect suggestions for designing camps. Through thematic analysis, five key themes are distilled which link outcomes of camps to addressing specific sustainability issues. The study concludes that nature camps already empower young people towards sustainability, though neither explicitly nor strategically. Based on these findings we see an excellent opportunity to bring together existing knowledge from the field, combined with the YES Framework, to support the creation of nature camps which can empower new generations of young people to engage in strategic sustainable development.

The thesis deals with the benefits of modern technologies to public land transport, an area which has not been notably impacted by modern technologies to this day. The work anal-yses both the way modern technologies can help transport companies, and also which tech-nologies in particular can bring something new to the conservative sector. The specific ob-jectives of the thesis are the analysis of D2D systems key components, benefits of Yield Management to the transport industry and implementation of carriers into the Bileto plat-form.

Following some incidents in high-rise buildings, such as Ronan Point London 1968, in which collapse of a limited number of structural elements progressed to a failure disproportionate to the initial cause, consideration of robustness was introduced in British Standard. The main method of preventing progressive collapse for providing robustness to steel framed buildings with precast concrete floor slabs focuses on the allowable tying forces that the reinforcement in between the slabs and in hollowcores should carry. However there are uncertainties about the basis of the practical rules associated with this method. This thesis presents the results of numerical and analytical studies of tie connection behaviour between precast concrete floor slabs (PCFS). It is shown that under current design regulations the tie connection is not able to resist the accidental load limit applied on the damaged floor slabs. By establishing the capability of a finite element model to depict and predict the behaviour of concrete members in situations such as arching and catenary action against several experimental tests, an extensive set of parametric studies was conducted in order to identify the effective parameters in enhancing the resistance of the tie connection between PCFSs. These parameters include: tie bar diameter, position, length, yield stress and ultimate strain; the slab’s height, length; and the compressive strength of the grouting concrete in between the slabs that encases the tie bar. Recommendations are made based on the findings of this parametric study in order to increase the resistance of the tie connection. Based on the identified effective parameters in the parametric study a predictive analytical relationship is derived which is capable of determining the maximum vertical displacement and load that the tie connection is able to undergo. This relationship can be used to enable the connection to capture the accidental limit load on a damaged slab. The identified parameters are examined in a three dimensional finite element model to assess their effect when columns of the structure are lost in different locations such as an edge, corner or internal column. Based on the findings of this study methods for improving the connections performance are presented. Also the effect of alternative transverse tying method is evaluated and it is concluded that although this kind of tie increases the load carrying capacity of the connection, its effect on the catenary action is not significant.

Concrete-Filled Steel Tubular (CFST) columns are increasingly being used because of their many advantages, including high strength, high ductility, and higher fire resistance than conventional steel or concrete columns of the same size. In order to maximise the advantages of CFST column, composite action of the column should be ensured. In realistic structures, the load is not directly applied to the entire CFST column section and is introduced from the beam-column connection. Simple shear connections, which are usually preferred in constructions, are only connected to the external face of the steel tube and there is an issue about how this load is introduced to the concrete core, through the bond at the steel/concrete interface. There are fundamental errors in the load introduction mechanism assumed in various current design methods. Furthermore, based on this erroneous load introduction mechanism, construction methods, such as placing shear connectors inside the steel tube or using through-column plates, are recommended to ensure complete load introduction. However, these methods are either impractical or uneconomical. The aim of this project, therefore, is to develop a thorough understanding of the load introduction mechanism and to use the new insights to assess design implications, for both ambient temperature and fire safety design. The research has been conducted through physical testing, extensive numerical modelling and detailed analytical derivations. A series of new load introduction tests, in which square CFST columns are loaded through simple fin plate connections, are carried out. These tests are designed to investigate the effects of changing column lengths below and above the connection, the effectiveness of using shear connectors inside the steel tube below the connection (according to Eurocode 4) and using a cap plate on the column top for load introduction into the concrete core. The test results indicate that the connection load is introduced to the concrete core through the column length above and within the connection or the cap plate on top of the column. This is different from the currently assumed mechanism of load introduction which assumes that load introduction occurs from underneath the connection. Below the connection, there is transfer of forces from the steel tube to the concrete core, but the total force in the column remains unchanged. Consequently, using shear connectors below the connection is ineffective in increasing CFST column strength, as has been demonstrated by the tests. The physical tests are supplemented by an extensive numerical parametric study to check whether the conclusions are applicable to different design conditions and to provide data for development of a new design method. The parameters include: section geometry (square, circular, and rectangular), position of load application to CFST column, dimensions of the square column cross-section, steel tube thickness, connection length, column length above the connection, column length below the connection, and maximum bond stress at the steel-concrete interface. The numerical simulation results confirm the experimental observations. Furthermore, the numerical simulation results indicate that the entire column length and the entire perimeter of the steel-concrete interface above and within the connection are engaged in load introduction. Based on the experimental and numerical simulation results, a simple calculation method has been proposed to calculate the column cross-section resistance under compression. According to this equation, the concrete compression resistance to the composite column is the minimum of the plastic resistance or the bond strength within and above the connection. This gives rise to a “concrete strength reduction factor” to account for incomplete load introduction, being the ratio of the load introduced to the concrete core through the interface bond to the concrete plastic resistance. Based on the new load introduction calculation method and using representative values of column dimensions and concrete cylinder strength, it has been demonstrated that complete load introduction can be achieved in almost all practical arrangements of concrete-filled tubular construction. For slender CFST column design, this concrete strength reduction factor should also be used to calculate the CFST column cross-section flexural stiffness. For a CFST column under combined axial compression and bending, the concrete strength reduction factor should be used when calculating the compression force, but should be ignored when calculating the bending resistance because composite action is not necessary for bending of the CFST column. The new load introduction mechanism induces additional compression in the concrete core and possible tension in the steel tube above the connection. Therefore, the concrete core of the column above the connection in multi-storey construction should be designed to resist the additional compression force. For the steel tube, in ambient temperature design, the steel contribution ratio (steel section resistance/plastic resistance of composite cross-section) of the top floor column should be at least 0.25. For fire resistance design, the steel contribution ratio of the top floor columns, those on the floor below the top floor, and those two floors below the top floor, should not be less than 0.5, 0.33, and 0.25 respectively.

In this paper we have developed a general theory of characteristic classes of modules. To a given invariant map defined on a Lie algebra, we associate a cohomology class by using the curvature form of a certain kind of connections. Here we present a very simple proof of the invariance theorem (Theorem 12), which states that equivalent connections give rise to the same characteristic class. We have used those invariant maps of {9} to define Chern classes of projective modules and we have derived their basic properties. It might be interesting to observe that this theory could be applied to define characteristic classes of bilinear maps. In particular, the Euler classes of {6} can be obtained in this way.

Cette thèse a pour but de résoudre certains problèmes de connexion et de décrire diverses propriétés asymptotiques des fonctions de Painlevé V et I. Dans le cas de l’équation de Painlevé V, nous approchons ces problèmes en développant une nouvelle approche basée sur la théorie conforme des champs bidimensionelle. Nous proposons de calculer les blocs conformes irréguliers de première et seconde espèce par confluence des blocs conformes réguliers de Virasoro. Une conséquence de cette construction est la solution du problème de connexion de l’équation de Painlevé V entre 0 et +i∞. Les formules pour les normalisations relatives (constantes de connexion) de la fonction tau de Painlevé V entre 0, +∞, et +i∞ sont également proposées. Enfin, le développement asymptotique complet de la fonction tau à courte distance pour des données de monodromie génériques est prouvé. Ce résultat est obtenu en construisant une représentation de la fonction tau en termes d’un déterminant de Fredholm. Dans le cas de l’équation de Painlevé I, nous présentons les constantes de connexion relatant les asymptotiques de la fonction tau sur les cinq raies canoniques à l’infini. Ce résultat est obtenu en construisant une extension de la forme différentielle de Jimbo-Miwa-Ueno à l’espace des données de monodromie. Ces constantes de connexion sont exprimées en termes de dilogarithmes de coordonnées de type cluster dans l’espace des données de Stokes. / The aim of this thesis is to solve several connection problems and describe asymptotic properties of Painlevé V and I functions. In the case of Painlevé V equation, we approach these problems by developing a new toolbox based on two dimensional conformal field theory. We propose to compute irregular conformal blocks of the first and second kind by confluence of regular Virasoro conformal blocks. One consequence of this construction is the solution of the connection problem for Painlevé V equation between 0 and +i∞. Formulas for the relative normalizations (connection constants) of Painlevé V tau function between 0, +∞, and +i∞ are also proposed. Finally, the full asymptotic expansion of the tau function at short distances for generic monodromy data is proved. This result is obtained by constructing a Fredholm determinant representation for the tau function. In the case of Painlevé I equation, we present connection constants relating asymptotics of the tau function on the five canonical rays at infinity. This result is obtained by extending the definition of the Jimbo-Miwa-Ueno differential to the space of monodromy data. These connection constants are expressed in terms of dilogarithms of cluster type coordinates on the space of Stokes data.

Le but de cette thèse est d'étudier différents exemples des variétés de caractères régulières et sauvages des courbes complexes.La première partie est consacrée à l'étude d'un exemple de variété de caractères de la sphère avec quatre trous et groupe exotique G₂ comme son groupe de structure. On démontre que pour un choix particulier de classes de conjugaison du groupe G₂ , la variété obtenue est de dimension complexe deux et isomorphe à la surface cubique de Fricke—Klein. Cette surface apparaît déjà dans le cas classique comme la variété de caractères de cette surface avec le groupe de structure SL₂ (C). De plus, on interprète les orbites de groupe de tresses de taille 7 dans cette surface comme les droites passant par les triplés de points dans le plan de Fano P² (F₂).Dans la deuxième partie, on établit plusieurs cas de la „conjecture d'écho”, correspondant aux équations différentielles de Painlevé I, II et IV. On montre que sur la sphère de Riemann avec un point singulier, pour des choix particuliers de la singularité il y a trois familles infinies de variétés de caractères sauvages de dimension complexe deux. Dans ces familles, le rang du groupe de structure n'est pas borné et augmente jusqu'à l'infini. Le résultat principal de cette partie démontre que tous les membres de ces trois familles de variétés sont isomorphes aux espaces de phase des équations de Painlevé associées. En calculant les quotients de la théorie géométrique des invariants, on fournit des isomorphismes explicites entre les anneaux de fonctions des variétés affines qui apparaissent et relie les paramètres des surfaces cubiques.Dans la dernière partie, avec des outils de la géométrie quasi-Hamiltonienne, on étudie une famille des espaces généralisant les hiérarchies de Painlevé I et II pour les groupes linéaires de rang supérieur. En particulier, pour toute variété Bk dans la hiérarchie il y a une application moment, prenant ses valeurs dans un groupe, qui s'avère être un polynôme continuant d'Euler. Ces polynômes admettent des factorisations en continuants plus courts et on montre que les factorisations d'un polynôme continuant de longueur k en termes de longueur un sont énumérées par le nombre de Catalan Ck. De plus, chaque factorisation fournit un plongement du produit de fusion de k copies de GLn (C) sur un ouvert dense de Bk et on démontre que ces plongements relient les structures quasi-Hamiltoniennes. Finalement, on utilise ce résultat pour dériver une formule explicite pour la 2-forme quasi-Hamiltonienne sur Bk, généralisant la formule connue dans le cas de B₂ . / The aim of this thesis is to study various examples of tame and wild character varieties of complex curves.In the first part, we study an example of a tame character variety of the four-holed sphere with simple poles and exotic group G₂ as the structure group. We show that for a particular choice of conjugacy classes in G₂, the resulting affine symplectic variety of complex dimension two is isomorphic to the Fricke-Klein cubic surface, known from the classical case of the character variety for the group SL₂(C). Furthermore, we interpret the braid group orbits of size 7 in this affine surface as lines passing through triples of points in the Fano plane P²(F₂).In the second part, we establish multiple cases of the so-called „echo conjecture”, corresponding to the cases of Painleve I, II and IV differential equations. We show that for the Riemann sphere with one singular point and suitably chosen behavior at the singularity, there are three infinite families of wild character varieties of complex dimension two. In these families, the rank of the structure group is not bounded and goes to infinity. The main result of this part shows that in each family all the members are affine cubic surfaces, isomorphic to the phase spaces of the aforementioned Painleve equations. By computing the geometric invariat theory quotients, we provide explicit isomorphisms between the rings of functions of the arising affine varieties and relate the coefficients of the affine surfaces.The last part is dedicated to the study of a family of spaces generalizing the Painleve I and II hierarchies for higher rank linear groups, which is done by the means of quasi-Hamiltonian geometry. In particular, for each variety Bk in the hierarchy there is a group-valued moment map and they turn out to be the Euler's continuant polynomials. These in turn admit factorisations into products of shorter continuants and we show that for a continuant of length k, the distinct factorisations into continuants of length one are counted by the Catalan number Ck. Moreover, each such factorisation provides an embedding of the fusion product of k copies of GLn(C) onto a dense open subset of B_k and the quasi-Hamiltonian structures do match up. Finally, using this result we derive the formula for the quasi-Hamiltonian two form on the space Bk, which generalises the formula known for the case of B₂.

This study analyses mistrust of media. Door-to-door interviews were conducted with 318 respondents in six different parts of Sweden. In 2015 the Swedish research institute SOM published an interesting study of mistrust of media in Sweden, showing that the group that mistrust the media is dominated by supporters of the Sweden Democrats. The aim of this study is to gain understanding of the causes and nature of mistrust of media. The interviews featured both open and closed questions, covering political interest and the respondents opinions about what is good and less good in society. This essay primarily analyses the issues that concern trust in the media linked to community involvement. This essay is based on the framework of a larger study by the think tank Arena Idé. The interviews were conducted by 10 interviewers and the coding of the material was done by a person employed by the think tank. For the interview guide, a code scheme was created and the computer programme Nvivo was used for the coding. Employing theories about public connection and the hostile media effect, this study aims to provide a better understanding of popular mistrust. The findings point to the conclusion that there are reasons to believe that a hostile media effect exists. The expressions of mistrust of media are classified into three different themes: Source criticism, Alleged obfuscation of truth, and Angling of media. The connection to society in the group with a low level of trust in the media is found to be narrow but intense.

It is becoming a problem that the number of people who have loneliness by a physical distance between family members has lately kept increasing. Home is not only about space, but also about where an individual makes memories, feels secured with its familiarity and feels comfortable with his or her family member(s). Individuals, who live alone and feel lonely, have not been getting these senses. The available ways of connection between remote family members are not enough.  The aim of the research is to understand the current condition of the connection between remote family members to map pain points. The purpose is to develop a product that can decrease a sense of loneliness and increase positive emotions through an experience which makes a lonely individual feel a little bit more connected to a long-distance family in everyday life.  Based on the in-depth interviews, eight insights and two kinds of stakeholders, whom the connection should be made between, was revealed. Over forty ideas were created to solve the problem of loneliness based on the defined insights and stakeholders, and the ideas were narrowed down on the criteria of to what extent the idea can satisfy the revealed insights and to what extent the connection created by each idea can last easily between the two stakeholders.  The resulting product called One Home Lamp can provide an emotionally warmer experience to a target user than other similar products do with four main features: 1) a connection which lasts in everyday life in a way that everyone can keep in touch with each other more easily, 2) a better sense of identity which belongs to each family by customization with colour and stickers, 3) a better sense of belongingness towards a family by seeing an imaginal house where you and your family live together, 4) a better sense of touch which is closer to human warmth with the material and soft texture used.  The result is beneficial for modern societies in terms of the fact that it has a great possibility to reduce loneliness, increase positive emotions and improve well-being among lonely individuals which is one of the sustainable development goals to be achieved by 2030 advocated by the United Nations General Assembly.