O objetivo deste trabalho foi investigar barreiras, motivações e estratégias que apresentam potencial para promover a mobilidade sustentável de alunos de graduação, pós-graduação, servidores técnico- administrativos e servidores docentes no campus da Universidade de São Paulo em São Carlos. O método utilizado para atingir o objetivo foi dividido em três etapas: i. desenvolvimento de ferramenta para coleta de dados; ii. análise dos dados por meio do modelo transteórico de mudança comportamental; iii. análise de estratégias visando a mobilidade sustentável. O questionário on-line desenvolvido e aplicado para o estudo forneceu uma taxa de resposta robusta e bem distribuída dos principais usuários do campus (25,5% da população do campus total). Percentagens consideráveis de usuários em todos os grupos investigados manifestaram a intenção de mudar para outro modo de transporte. Entre aqueles que mudariam para modos de transporte sustentáveis, 27,1% mudariam para o modo a pé, enquanto que 46,2% mudariam para o modo bicicleta. No entanto, 13,6% dos entrevistados declararam que mudariam para o automóvel, o que representa uma demanda adicional de cerca de 300 lugares de estacionamento no campus. Em relação às barreiras para a adoção de modos de transporte sustentáveis, a posse de um veículo motorizado foi o principal obstáculo identificado (independentemente do modo a ser adotado como uma alternativa). Duas alternativas foram classificadas como as melhores estratégias para promoção da mobilidade sustentável no contexto estudado: a construção de ciclovias que ligam o campus com a rede viária urbana e estacionamento para bicicletas dentro do campus. Uma avaliação adicional da primeira alternativa demonstrou significativo potencial para servir a usuários de vários modos de transporte, com grande impacto positivo sobre o modo a pé. Outra estratégia também testada foi a abertura de novos pontos de acesso para pedestres no campus. Estimou-se que sua implantação resultaria em uma redução de 20% nas distâncias de viagem a pé dos alunos. / The objective of this study was to investigate barriers, motivators and strategies with potential to promote sustainable mobility for graduate and undergraduate students, staff and faculty at the campus of the University of São Paulo at São Carlos. The method used to reach the objective had three steps: i. development of a data collection tool; ii. analysis of the data with the transtheoretical model of behavior change; iii. analysis of strategies aiming at sustainable mobility. The online questionnaire developed and applied for the study provided a robust and well-distributed response rate of the main users (25.5% of the total campus population). Considerable percentages of users in all groups investigated have declared that would eventually change to another travel mode. Among those who would change to sustainable modes, 27.1% would change to the walking mode, whereas 46.2% would change to the cycling mode. However, 13.6% of the respondents declared they would change to the automobile, what represents an additional demand of approximately 300 parking spaces in the campus. Regarding the barriers to the adoption of sustainable modes, owning a motorized vehicle was identified as the main obstacle (regardless of the mode to be adopted as an alternative). Two alternatives have been rated as the best strategies for promoting sustainable mobility in the studied context: the construction of cycling paths connecting the campus with the urban street network and parking facilities for bicycles within the campus. An additional evaluation of the first alternative has shown a significant potential to serve users of several transport modes, with a large positive impact on pedestrians. Another strategy also tested was the opening of new access points to pedestrians in the campus. This strategy could reduce the total walking distance travelled by the students in 20%.

<p> The light even-even nuclei have been studied using the den~ity dependent effective interaction of Sprung and Banerjeee The nuclei were studied initially, using a harmonic variational procedure, to deter mine the most appropriate parameters of t he force for the Hartree Fock study. </p> <p> This chosen force was then used in a comparative study of spherical nuclei to d e termine the inadequacies of our Hartn~e Fock approach, as opposed to the spherical basis calculations of Campi. Some deformed nuclei were then examined and our results were compared with those of K. Lassey and A. B. Volkov , and of J. Zofka and G. Ripka. </p> / Thesis / Master of Science (MSc)

In this thesis, an inverse source (IS) approach is considered for the constrained design of static-passive electromagnetic skins (SP-EMSs). By leveraging the ill-posedness/non-uniqueness of the IS problem at hand, a generalized solution framework is devised for the synthesis of SP-EMSs that simultaneously comply with (i) complex wireless coverage requirements and (ii) manufacturing and installation constraints. These two design goals can be decoupled and tackled separately through the employment of non-radiating (NR) currents. The flexibility of the IS-based formulation is demonstrated in practice with the implementation of two synthesis strategies dealing with different classes of design constraints. Representative results from a wide set of numerical experiments are reported to prove the effectiveness and the computational efficiency of the proposed method as a suitable tool for a real and effective realization of the so-called smart electromagnetic environment (SEME).

The Terahertz (THz) band of the electromagnetic spectrum, also defined as sub-millimeter waves, covers the frequency range from 300 GHz to 10 THz. There are several unique characteristics of the radiation in this frequency range such as the non-ionizing nature, since the associated power is low and therefore it is considered as safe technology in many applications. THz waves have the capability of penetrating through several materials such as plastics, paper, and wood. Moreover, it provides a higher resolution compared to conventional mmWave technologies thanks to its shorter wavelengths. The most promising applications of the THz technology are medical imaging, security/surveillance imaging, quality control, non-destructive materials testing and spectroscopy. The potential advantages in these fields provide the motivation to develop room-temperature THz detectors. In terms of low cost, high volume, and high integration capabilities, standard CMOS technology has been considered as an excellent platform to achieve fully integrated THz imaging systems. In this Ph.D. thesis, we report on the design and development of field effect transistor (FET) THz direct detectors operating at low THz frequency (e.g. 300 GHz), as well as at higher THz frequencies (e.g. 800 GHz – 1 THz). In addition, we investigated the implementation issues that limit the power coupling efficiency with the integrated antenna, as well as the antenna-detector impedance-matching condition. The implemented antenna-coupled FET detector structures aim to improve the detection behavior in terms of responsivity and noise equivalent power (NEP) for CMOS based imaging applications. Since the detected THz signals by using this approach are extremely weak with limited bandwidth, the next section of this work presents a pixel-level readout chain containing a cascade of a pre-amplification and noise reduction stage based on a parametric chopper amplifier and a direct analog-to-digital conversion by means of an incremental Sigma-Delta converter. The readout circuit aims to perform a lock-in operation with modulated sources. The in-pixel readout chain provides simultaneous signal integration and noise filtering for the multi-pixel FET detector arrays and hence achieving similar sensitivity by the external lock-in amplifier. Next, based on the experimental THz characterization and measurement results of a single pixel (antenna-coupled FET detector + readout circuit), the design and implementation of a multispectral imager containing 10 x 10 THz focal plane array (FPA) as well as 50 x 50 (3T-APS) visible pixels is presented. Moreover, the readout circuit for the visible pixel is realized as a column-level correlated double sampler. All of the designed chips have been implemented and fabricated in 0.15-µm standard CMOS technology. The physical implementation, fabrication and electrical testing preparation are discussed.

Ce travail de recherche s’intéresse aux processus de construction d’un problème public à une échelle locale, en partant des différentes questions nées autour de campements de travailleurs saisonniers migrants dans des régions d’agriculture intensive en Italie. Il est principalement basé sur une recherche empirique menée entre 2013 et 2017 dans la zone rurale de Saluzzo (Piémont) avec une méthodologie qualitative croisant entretiens sociologiques, observation participante au sein de collectifs militants et à l’intérieur des campements de migrants et analyse d’articles de presse locale. L’objectif principal était celui d’étudier la façon dont la présence de migrants dans ce contexte spécifique est perçue comme un problème public, de quelle manière ce dernier est défini et construit dans un jeu de mobilisations et contremobilisations par une multitude d’acteurs aux intérêts divergents, puis d’analyser les conséquences de ces dynamiques sur les actions mises en places pour tenter de le résoudre. La thèse démontre en particulier comment la construction du problème se focalise progressivement sur le caractère temporaire de la présence des migrants, au détriment d’autres possibles cadrages, en justifiant la mise en place de dispositifs d’accueil provisoires et précaires, conduisant au confinement spatial et temporel des migrants. On verra également comme la création de camps de plus en plus institutionnalisés et contrôlés, gérés par une association humanitaire bénéficiant d’un large consensus, a favorisé un apaisement des conflits autour de cette question et un éloignement du problème au sein du débat politique public. D’une façon plus générale, ce travail, en analysant une question inhérente aux faits migratoires par le prisme de la sociologie politique, invite à une réflexion plus ample sur le traitement politique des migrants et sur la construction collective de la place qu’ils occupent aujourd’hui au sein de la société italienne. / This 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.

Attraverso un ampio studio di campo, il contributo propone un'analisi sociologica della fotografia in Italia e della sua parziale legittimazione artistica. Prendendo in considerazione sia lo sviluppo storico del campo della fotografia artistica in Italia che la sua condizione contemporanea, lo studio si concentra sui processi attraverso cui diversi attori e istituzioni promuovono la legittimità e lo status della fotografia come arte. Combinando la sociologia dell'arte e dei processi culturali con gli studi organizzativi, la ricerca sviluppa un quadro interpretativo che delinea la relazione tra legittimazione, categorizzazione sociale e processi di valutazione culturale. La ricerca, adottando la metodologia della Constructivist Grounded Theory, raccoglie e analizza diverse fonti: interviste faccia a faccia con fotografi, critici, storici, curatori, galleristi, direttori di musei e collezionisti italiani; note etnografiche raccolte durante l'osservazione partecipante di vari eventi di arte e fotografia, come festival, fiere, presentazioni, visite a musei e aperture di gallerie; risultati d'asta (2009-2020) e analisi di mercato disponibili; dati secondari, come libri di storia e opere critiche sulla fotografia italiana, documenti di archivio e comunicati stampa. I risultati mostrano che la fotografia in Italia sta ancora lottando per assicurarsi uno statuto di forma d'arte legittima a causa di processi storici e dinamiche socio-economiche che rafforzano il confine simbolico tra il mondo professionale della fotografia e quello legittimo dell'arte contemporanea. Rispetto ad altri paesi europei, il campo della fotografia artistica è emerso tardi, solo alla fine degli anni '70, in seguito all'emergere di tre spazi di opportunità favorevoli, in particolare la crisi del fotogiornalismo italiano. Di conseguenza, i membri del campo della fotografia artistica hanno sviluppato strategie di mobilitazione delle risorse e di teorizzazione di un'ideologia legittimante ancora in fase di sviluppo. Inoltre, il contributo teorizza tre processi di legittimazione che, agendo in combinazione tra loro, stabiliscono le condizioni per la completa legittimazione della fotografia come arte: differenziazione, emulazione e sublimazione. Questi processi, discussi alla luce di esperienze empiriche di legittimazione sia completa che parziale, mostrano che il campo della fotografia occupa una posizione di "inclusione segregata" all'interno delle istituzioni artistiche, poiché persiste ancora una contestata identificazione della fotografia come arte. / Through an in-depth field study, this thesis provides a sociological analysis of photography in Italy and its partial artistic legitimation. Taking into account both the historical development of the field of art photography in Italy and its contemporary condition, the study focuses on the processes through which different actors and institutions promote the legitimacy and status of photography as art. Combining the sociology of art and cultural processes to organisation studies, the study develops an interpretative framework that spells out the relationship between legitimation, social categorisation and cultural evaluation processes. Adopting the Constructivist Grounded Theory methodology, the research collects and analyses different sources: face-to-face interviews with photographers, critics, historians, curators, gallery owners, museum directors and Italian collectors; ethnographic notes collected during participant observation of various art and photography events, such as festivals, fairs, presentations, museum visits and gallery openings; auction data (collected from 2009 to 2020) and extant market analyses; secondary textual data, such as history and critical works on Italian photography, archival records and press releases. The results show that photography in Italy is still struggling to secure its status as a legitimate art form due to historical processes and socio-economic dynamics that reinforce the symbolic boundary between the professional world of photography and the legitimate world of contemporary art. Compared to other European countries, the field of artistic photography emerged late, only at the end of the 1970s, following the emergence of three favourable opportunity spaces, notably the crisis of Italian photojournalism. As a result, members of the field of artistic photography developed strategies of resource mobilisation and theorisation of a legitimising ideology that are still ongoing today. In addition, the contribution theorises three processes of legitimation which, acting in combination with each other, establish the conditions for the complete legitimation of photography as art: differentiation, emulation and sublimation. These processes, discussed in the light of empirical experiences of both full and partial legitimation, show that the field of photography occupies a position of "segregated inclusion" within art institutions, as a contested identification of photography as art still persists.

[pt] Esse trabalho se dedica a uma análise de ordem projetual e construtiva do Pavilhão João Lyra Filho, edifício principal do Campus Francisco Negrão de Lima, sede da Universidade do Estado do Rio de Janeiro (UERJ). O campus, objeto de um concurso realizado pela Universidade em 1968, no qual os arquitetos Flávio Marinho Rêgo e Luiz Paulo Conde foram os vencedores, tem origem em um período de transição da arquitetura moderna brasileira e de expansão da estrutura voltada para o ensino superior no Brasil e no mundo. Nesse período, surgem no cenário internacional propostas inovadoras de campi que dialogam com a ideia de megaestrutura. Stefan Muthesius, autor do livro The postwar university: Utopianist campus and college, publicado no ano 2000, reconhece esses campi como single structure campus, em uma tradução livre campus de estrutura única. Essa classificação remete à campi em que o complexo programa universitário se concentra majoritariamente em um único edifício. Nesses casos, campus e edifício se confundem em uma única estrutura, impossibilitando dissociarmos um do outro. / [en] This work is dedicated to an analysis of the design and construction order of the João Lyra Filho Pavilion, the main building on the Francisco Negrão de Lima Campus, headquarters of the Universidade Estadual do Rio de Janeiro (UERJ). The campus, the object of a competition held by the University in 1968, in which the architects Flávio Marinho Rêgo and Luiz Paulo Conde were the winners, has its origins in a period of transition of modern Brazilian architecture and expansion of the structure aimed at higher education in Brazil. During this period, innovative proposals for campuses that dialogue with the idea of megastructure emerged on the international scene. Stefan Muthesius, author of the book The postwar university: Utopianist campus and college, published in 2000, recognizes these campuses as single structure campus. This classification refers to campuses such as UERJ, where the complex university program is concentrated in a single building, in the case of the University in the João Lyra Filho Pavilion. In these cases, campus and building are confused in a single structure, making it impossible for us to dissociate from each other.

Modern communication and space systems such as satellite communication devices, radars, SAR and radio astronomy interferometers are realized with large antenna arrays since this kind of radiating systems are able to generate radiation patterns with high directivity and resolution. In such a framework conventional arrays with uniform inter-element spacing could be not satisfactory in terms of costs and dimensions. An interesting alternative is to reduce the array elements obtaining the so called "thinned arrays". Large isophoric thinned arrays have been exploited because of their advantages in terms of weight, consumption, hardware complexity, and costs over their filled counterparts. Unfortunately, thinning large arrays reduces the control of the peak sidelobe level (PSL) and does not give automatically optimal spatial frequency coverage for correlators. First of all the state of the art methodologies used to overcome such limitations, e.g., random and algorithmic approaches, dynamic programming and stochastic optimization algorithms such as genetic algorithms, simulated annealing or particle swarm optimizers, are analyzed and described in the introduction. Successively, innovative guidelines for the synthesis of large radiating systems are proposed, and discussed in order to point out advantages and limitations. In particular, the following specific issues are addressed in this work: 1. A new class of analytical rectangular thinned arrays with low peak sidelobe level (PSL). The proposed synthesis technique exploits binary sequences derived from McFarland difference sets to design thinned layouts on a lattice of P(P+2) positions for any prime P. The pattern features of the arising massively-thinned arrangements characterized by only P(P+1) active elements are discussed and the results of an extensive numerical analysis are presented to assess advantages and limitations of the McFarland-based arrays. 2. A set of techniques is presented that is based on the exploitation of low correlation Almost Difference Sets (ADSs) sequences to design correlator arrays for radioastronomy applications. In particular three approaches are discussed with different objectives and performances. ADS-based analytical designs, GA-optimized arrangements, and PSO optimized arrays are presented and applied to the synthesis of open-ended "Y" and "Cross" array configurations to maximize the coverage u-v or to minimize the peak sidelobe level (PSL). Representative numerical results are illustrated to point out the features and performances of the proposed approaches, and to assess their effectiveness in comparison with state-of-the-art design methodologies, as well. The presented analysis indicates that the proposed approaches overcome existing PSO-based correlator arrays in terms of PSL control (e.g., &gt;1.0dB reduction) and tracking u-v coverage (e.g., up to 2\% enhancement), also improving the speed of convergence of the synthesis process. 3. A genetic algorithm (GA)-enhanced almost difference set (ADS)-based methodology to design thinned planar arrays with low-peak sidelobe levels (PSLs). The method allows to overcome the limitations of the standard ADS approach in terms of flexibility and performance. The numerical validation, carried out in the far-field and for narrow-band signals, points out that with affordable computational efforts it is possible to design planar array arrangements that outperform standard ADS-based designs as well as standard GA design approaches.

It is now broadly accepted that Vaughan Williams's music betrays a more complex relation to national influences than has traditionally been assumed. It is argued in this thesis that despite the trends towards revisionism that have characterized recent work, Vaughan Williams's interest in and engagement with English folk materials and cultures remains only partially understood. Offering contextual interpretation of materials newly available in the field, my work takes as its point of departure the critical neglect surrounding Vaughan Williams's contradictory compositional debut, in which he denounced the value of folk song in English art music in an article published alongside his song 'Linden Lea', subtitled 'A Dorset Folk Song'. Reconstructing the under-documented years of the composer's early career, it is demonstrated that Vaughan Williams's subsequent 'conversion' and lifelong attachment to folk song emerged as part of a broader concern with the intelligible and participatory quality of song and its performance by the human voice. As such, it is argued that the ways in which this composer theorized an idea of 'song' illuminate a powerful perspective from which to re-consider the propositions of his project for a national music. Locating Vaughan Williams's writings within contemporaneous cultural ideas and practices surrounding 'song', 'voice', and 'Englishness', this work brings such contexts into dialogue with readings of various of the composer's works, composed both before and after the First World War. It is demonstrated in this way that the rehabilitation of Vaughan Williams's music and reputation profitably proceeds by reconstructing a complex dialogue between his writings; between various cultural ideas and practices of English music; between the reception of his works by contemporaneous critics; and crucially, by considering the propositions of his music as explored through analysis. Ultimately, this thesis contends that Vaughan Williams's music often betrays a complex and self-conscious performance of cultural ideas of national identity, negotiating an optimistic or otherwise ambivalent relationship to an English musical tradition that is constructed and referenced through a particular idea of song.

La description détaillée des systèmes désordonnés et vitreux représente un défi central en physique statistique et de la matière condensée, puisqu'à ce jour il n'existe pas de théorie unique et établie permettant de comprendre ces systèmes, pourtant omniprésents.Ce travail de recherche est lié en particulier à l'étude des matériaux vitreux à basse température. Plus précisément, si l'on considère des systèmes formés par un ensemble de particules athermiques avec des interactions répulsives de portée finie, en augmentant la densité, on peut observer une transition dite d'encombrement ("jamming"). Celle-ci consiste en un blocage des degrés de liberté accompagné par une augmentation spectaculaire de la rigidité du matériau.Nous étudierons ce problème à l’aide d’une analogie formelle entre des modèles de sphères et le perceptron, un modèle théorique qui développe une transition d'encombrement et des phénomènes de frustration typiques des systèmes désordonnés.En tant que modèle en champ moyen, il permet d'obtenir des résultats analytiques précis et généralisables à des systèmes à haute dimension.L'enjeu majeur de cette étude est de reconstruire le spectre des modes de vibration et toutes les propriétés pertinentes d'une phase spécifique (correspondant au régime dit des sphères dures).Dans ce cadre, nous dériverons le potentiel effectif en fonction des paramètres d'ordre du modèle et nous montrerons qu'il est dominé à proximité du point de jamming par une interaction logarithmique non triviale, qui clarifiera le lien entre les forces de contact et les distances moyennes entre les particules, dans la région critique et au-delà.Comprendre pleinement la transition d'encombrement et les propriétés du perceptron nous permettra de faire des progrès dans plusieurs domaines reliés. En premier lieu, cela peut conduire à une théorie complète des systèmes amorphes, à la fois en dimension infinie et en dimension finie.De plus, le modèle du perceptron semble avoir un lien étroit avec des problèmes dits de Von Neumann. En effet, les systèmes biologiques et écologiques développent souvent des propriétés liées à une condition pseudo-critique en mettant en oeuvre des mécanismes d'optimisation de ressource-consommation.Est-il possible d'identifier un régime caractérisé par une brisure de symétrie? Quel serait le spectre de fluctuations d'énergie dans ces systèmes?Ce ne sont que quelques-unes des questions auxquelles nous essayerons de répondre dans cette thèse.Cependant, l'approximation de champ moyen peut parfois fournir des informationsincorrectes ou trompeuses, en particulier dans l'étude de certaines transitions de phase et la détermination des dimensions critiques inférieure et supérieure.Afin d'avoir une vue d'ensemble et pouvoir manipuler correctement des systèmes en dimension finie, dans la suite de la thèse nous discuterons comment obtenir un développement perturbatif systématique, applicable à tout modèle, à condition que ce dernier soit défini sur un réseau ou un graphe biparti.Notre motivation est en particulier liée à la possibilité d'étudier certaines transitions de phase du second ordre qui existent sur le réseau de Bethe - c'est-à-dire un réseau en arbre sans boucles dont chaque noeud a une connectivité fixe - mais qui sont qualitativement différentes ou absentes dans le modèle entièrement connecté correspondant. / The detailed description of disordered and glassy systems represents an open problem in statistical physics and condensed matter. As yet, there is no single, well-established theory allowing to understand such systems. The research presented in this thesis is related in particular to the study of glassy materials in the low-temperature regime. More precisely, considering systems formed by athermal particles subject to repulsive short-range interactions, upon progressively increasing the density, a so-called jamming transition can be detected. It entails a freezing of the degrees of freedom and hence a huge increase of the material rigidity.We shall study this problem in view of a formal analogy between sphere models and the perceptron, a theoretical model undergoing a jamming transition and frustration phenomena typical of disordered systems. Being a mean-field model, it allows to obtain exact analytical results, which are generalizable to more complex high-dimensional settings.The main aim is to reconstruct the vibrational spectrum and all the relevant properties of a specific phase of the perceptron, corresponding to the hard-sphere regime.In this framework, we will derive the effective potential as a function of the gaps between and forces among the particles, and we will show that it is dominated by a non-trivial logarithmic interaction near the jamming point. This interaction in turn will clarify the relations existing between the relevant variables of the system, in the critical jamming region and beyond.Understanding the jamming transition and the perceptron properties will allow us to make progress in several related fields. First, this study could lay part of the groundwork towards a complete theory of amorphous systems, in both infinite and finite dimensions. Furthermore, the perceptron model seems to a have a close connection with the so-called Von Neumann problems. Indeed, biological and ecological systems often develop pseudo-critical properties and give rise to general mechanisms of resource-consumption optimisation.Is the identification of a broken symmetry regime possible? What would it yield in terms of the spectrum of the energy fluctuations?These are just a few questions we shall attempt to answer in this context.However, the mean-field approximation can sometimes provide wrong or misleading information, especially in studying certain phase transitions and determining the exact lower and upper critical dimensions. To have a broad perspective and correctly deal with finite-dimensional systems, in the second part of the thesis we will discuss obtaining a systematic perturbative expansion which can be applied to any model, as long as defined on a lattice or a bipartite graph.Our motivation is in particular due to the possibility of studying relevant second-order phase transitions which exist on the Bethe lattice — a lattice with a locally tree-like structure and fixed connectivity for each node — but which are qualitatively different or absent in the corresponding fully-connected version.