Dynamic thermal performance of building components and application to the experimental and theoretical analysis of a ventilated façade

The general aim of this work is to contribute to the energy performance assessment of ventilated façades by the simultaneous use of experimental data and numerical simulations. A significant amount of experimental work was done on different types of ventilated façades with natural ventilation. The measurements were taken on a test building. The external walls of this tower are rainscreen ventilated façades. Ventilation grills are located at the top and at the bottom of the tower. In this work the modelling of the test building using a dynamic thermal simulation program (ESP-r) is presented and the main results discussed. In order to investigate the best summer thermal performance of rainscreen ventilated skin façade a study for different setups of rainscreen walls was made. In particular, influences of ventilation grills, air cavity thickness, skin colour, skin material, orientation of façade were investigated. It is shown that some types of rainscreen ventilated façade typologies are capable of lowering the cooling energy demand of a few percent points.

The role of collective action in the provision of agri-environmental public goods: theoretical development through case studies in Italy

The thesis aims at analysing the role of collective action as a viable alternative to the traditional forms of intervention in agriculture in order to encourage the provision of agri-environmental public goods. Which are the main benefits of collective action, in terms of effectiveness and efficiency, compared to traditional market or public intervention policies? What are the drivers that encourage farmers to participate into collective action? To what extent it is possible to incorporate collective aspects into policies aimed at providing agri-environmental public goods? With the objective of addressing these research questions, the thesis is articulated in two levels: a theoretical analysis on the role of collective action in the provision of public goods and a specific investigation of two local initiative,s were an approach collective management of agro-environmental resources was successfully implemented. The first case study concerns a project named “Custodians of the Territory”, developed by the local agency in Tuscany “Comunità Montana Media Valle del Serchio”, which settled for an agreement with local farmers for a collective provision of environmental services related to the hydro-geological management of the district. The second case study is related to the territorial agri-environmental agreement experimented in Valdaso (Marche), where local farmers have adopted integrated pest management practices collectively with the aim of reducing the environmental impact of their farming practices. The analysis of these initiatives, carried out through participatory methods (Rapid Rural Appraisal), allowed developing a theoretical discussion on the role of innovative tools (such as co-production and co-management) in the provision of agri-environmental public goods. The case studies also provided some recommendations on the government intervention and policies needed to promote successful collective action for the provision of agri-environmental public goods.

Distributed optimization and games over networks: a system theoretical perspective

Several decision and control tasks involve networks of cyber-physical systems that need to be coordinated and controlled according to a fully-distributed paradigm involving only local communications without any central unit. This thesis focuses on distributed optimization and games over networks from a system theoretical perspective. In the addressed frameworks, we consider agents communicating only with neighbors and running distributed algorithms with optimization-oriented goals. The distinctive feature of this thesis is to interpret these algorithms as dynamical systems and, thus, to resort to powerful system theoretical tools for both their analysis and design. We first address the so-called consensus optimization setup. In this context, we provide an original system theoretical analysis of the well-known Gradient Tracking algorithm in the general case of nonconvex objective functions. Then, inspired by this method, we provide and study a series of extensions to improve the performance and to deal with more challenging settings like, e.g., the derivative-free framework or the online one. Subsequently, we tackle the recently emerged framework named distributed aggregative optimization. For this setup, we develop and analyze novel schemes to handle (i) online instances of the problem, (ii) ``personalized'' optimization frameworks, and (iii) feedback optimization settings. Finally, we adopt a system theoretical approach to address aggregative games over networks both in the presence or absence of linear coupling constraints among the decision variables of the players. In this context, we design and inspect novel fully-distributed algorithms, based on tracking mechanisms, that outperform state-of-the-art methods in finding the Nash equilibrium of the game.

Intangible resources and organization capital: measurement and economic evaluation

Intangible resources have raised the interests of scholars from different research areas due to their importance as crucial factors for firm performance; yet, contributions to this field still lack a theoretical framework. This research analyses the state-of-the-art results reached in the literature concerning intangibles, their main features and evaluation problems and models. In search for a possible theoretical framework, the research draws a kind of indirect analysis of intangibles through the theories of the firm, their critic and developments. The heterodox approaches of the evolutionary theory and resource-based view are indicated as possible frameworks. Based on this theoretical analysis, organization capital (OC) is identified, for its features, as the most important intangible for firm performance. Empirical studies on the relationship intangibles-firm performance have been sporadic and have failed to reach firm conclusions with respect to OC; in the attempt to fill this gap, the effect of OC is tested on a large sample of European firms using the Compustat Global database. OC is proxied by capitalizing an income statement item (Selling, General and Administrative expenses) that includes expenses linked to information technology, business process design, reputation enhancement and employee training. This measure of OC is employed in a cross-sectional estimation of a firm level production function - modeled with different functional specifications (Cobb-Douglas and Translog) - that measures OC contribution to firm output and profitability. Results are robust and confirm the importance of OC for firm performance.

Population ageing, longevity and migration: an overlapping generations approach

The silent demographic revolution characterizing the main industrialized countries is an unavoidable factor which has major economic, social, cultural and psychological implications. This thesis studies the main consequences of population ageing and the connections with the phenomenon of migration, The theoretical analysis is developed using Overlapping Generations Models (OLG). The thesis is divided in the following four chapters: 1) “A Model for Determining Consumption and Social Assistance Demand in Uncertainty Conditions”, focuses on the relation between demographic impact and social insurance and proposes the institution of a non selfsufficiency fund for the elderly. 2) "Population Ageing, Longevity and Health", analyzes the effects of health investment on intertemporal individual behaviour and capital accumulation. 3) "Population Ageing and the Nursing Flow", studies the consequences of migration in the nursing sector. 4) "Quality of Multiculturalism and Minorities' Assimilation", focuses on the problem of assimilation and integration of minorities.

Wireless systems for the fourth generation

Today, third generation networks are consolidated realities, and user expectations on new applications and services are becoming higher and higher. Therefore, new systems and technologies are necessary to move towards the market needs and the user requirements. This has driven the development of fourth generation networks. ”Wireless network for the fourth generation” is the expression used to describe the next step in wireless communications. There is no formal definition for what these fourth generation networks are; however, we can say that the next generation networks will be based on the coexistence of heterogeneous networks, on the integration with the existing radio access network (e.g. GPRS, UMTS, WIFI, ...) and, in particular, on new emerging architectures that are obtaining more and more relevance, as Wireless Ad Hoc and Sensor Networks (WASN). Thanks to their characteristics, fourth generation wireless systems will be able to offer custom-made solutions and applications personalized according to the user requirements; they will offer all types of services at an affordable cost, and solutions characterized by flexibility, scalability and reconfigurability. This PhD’s work has been focused on WASNs, autoconfiguring networks which are not based on a fixed infrastructure, but are characterized by being infrastructure less, where devices have to automatically generate the network in the initial phase, and maintain it through reconfiguration procedures (if nodes’ mobility, or energy drain, etc..., cause disconnections). The main part of the PhD activity has been focused on an analytical study on connectivity models for wireless ad hoc and sensor networks, nevertheless a small part of my work was experimental. Anyway, both the theoretical and experimental activities have had a common aim, related to the performance evaluation of WASNs. Concerning the theoretical analysis, the objective of the connectivity studies has been the evaluation of models for the interference estimation. This is due to the fact that interference is the most important performance degradation cause in WASNs. As a consequence, is very important to find an accurate model that allows its investigation, and I’ve tried to obtain a model the most realistic and general as possible, in particular for the evaluation of the interference coming from bounded interfering areas (i.e. a WiFi hot spot, a wireless covered research laboratory, ...). On the other hand, the experimental activity has led to Throughput and Packet Error Rare measurements on a real IEEE802.15.4 Wireless Sensor Network.

Enabling Blocks for Integrated CMOS UWB Transceivers

The last decades have seen an unrivaled growth and diffusion of mobile telecommunications. Several standards have been developed to this purposes, from GSM mobile phone communications to WLAN IEEE 802.11, providing different services for the the transmission of signals ranging from voice to high data rate digital communications and Digital Video Broadcasting (DVB). In this wide research and market field, this thesis focuses on Ultra Wideband (UWB) communications, an emerging technology for providing very high data rate transmissions over very short distances. In particular the presented research deals with the circuit design of enabling blocks for MB-OFDM UWB CMOS single-chip transceivers, namely the frequency synthesizer and the transmission mixer and power amplifier. First we discuss three different models for the simulation of chargepump phase-locked loops, namely the continuous time s-domain and discrete time z-domain approximations and the exact semi-analytical time-domain model. The limitations of the two approximated models are analyzed in terms of error in the computed settling time as a function of loop parameters, deriving practical conditions under which the different models are reliable for fast settling PLLs up to fourth order. Besides, a phase noise analysis method based upon the time-domain model is introduced and compared to the results obtained by means of the s-domain model. We compare the three models over the simulation of a fast switching PLL to be integrated in a frequency synthesizer for WiMedia MB-OFDM UWB systems. In the second part, the theoretical analysis is applied to the design of a 60mW 3.4 to 9.2GHz 12 Bands frequency synthesizer for MB-OFDM UWB based on two wide-band PLLs. The design is presented and discussed up to layout level. A test chip has been implemented in TSMC CMOS 90nm technology, measured data is provided. The functionality of the circuit is proved and specifications are met with state-of-the-art area occupation and power consumption. The last part of the thesis deals with the design of a transmission mixer and a power amplifier for MB-OFDM UWB band group 1. The design has been carried on up to layout level in ST Microlectronics 65nm CMOS technology. Main characteristics of the systems are the wideband behavior (1.6 GHz of bandwidth) and the constant behavior over process parameters, temperature and supply voltage thanks to the design of dedicated adaptive biasing circuits.

L'idea di metafora nell'opera di Oswald Mathias Ungers

This research focuses on the definition of the complex relationship that exists between theory and project, which - in the architectural work by Oswald Mathias Ungers - is based on several essays and on the publications that - though they have never been collected in an organic text - make up an articulated corpus, so that it is possible to consider it as the foundations of a theory. More specifically, this thesis deals with the role of metaphor in Unger’s theory and its subsequent practical application to his projects. The path leading from theoretical analysis to architectural project is in Ungers’ view a slow and mediated path, where theory is an instrument without which it would not be possible to create the project's foundations. The metaphor is a figure of speech taken from disciplines such as philosophy, aesthetics, linguistics. Using a metaphor implies a transfer of meaning, as it is essentially based on the replacement of a real object with a figurative one. The research is articulated in three parts, each of them corresponding to a text by Ungers that is considered as crucial to understand the development of his architectural thinking. Each text marks three decades of Ungers’ work: the sixties, seventies and eighties. The first part of the research deals with the topic of Großform expressed by Ungers in his publication of 1966 Grossformen im Wohnungsbau, where he defines four criteria based on which architecture identifies with a Großform. One of the hypothesis underlying this study is that there is a relationship between the notion of Großform and the figure of metaphor. The second part of the thesis analyzes the time between the end of the sixties and the seventies, i.e. the time during which Ungers lived in the USA and taught at the Cornell University of Ithaca. The analysis focuses on the text Entwerfen und Denken in Vorstellungen, Metaphern und Analogien, written by Ungers in 1976, for the exhibition MAN transFORMS organized in the Cooper - Hewitt Museum in New York. This text, through which Ungers creates a sort of vocabulary to explain the notions of metaphor, analogy, signs, symbols and allegories, can be defined as the Manifesto of his architectural theory, the latter being strictly intertwined with the metaphor as a design instrument and which is best expressed when he introduces the 11 thesis with P. Koolhaas, P. Riemann, H. Kollhoff and A. Ovaska in Die Stadt in der Stadt in 1977. Berlin das grüne Stadtarchipel. The third part analyzes the indissoluble tie between the use of metaphor and the choice of the topic on which the project is based and, starting from Ungers’ publication in 1982 Architecture as theme, the relationship between idea/theme and image/metaphor is explained. Playing with shapes requires metaphoric thinking, i.e. taking references to create new ideas from the world of shapes and not just from architecture. The metaphor as a tool to interpret reality becomes for Ungers an inquiry method that precedes a project and makes it possible to define the theme on which the project will be based. In Ungers’ case, the architecture of ideas matches the idea of architecture; for Ungers the notions of idea and theme, image and metaphor cannot be separated from each other, the text on thematization of architecture is not a report of his projects, but it represents the need to put them in order and highlight the theme on which they are based.

International openness in transition countries: further evidence on foreign direct investment

The thesis focuses on the process of international openness of Transition Countries. This study provides a theoretical analysis based on reference literature, and an empirical analysis which is aimed at estimating some main effects of Foreign Direct Investment. Transition has represented a highly complex phenomenon, characterized by several aspects, whose interaction has shaped the developmental path of each country involved. Although the thesis focuses on economic issues it is outstanding to underline that Transition implies political, institutional, and even social deep changes, which must be taken into consideration in the general overview of the contex. The empirical part has been developed along two different ways: a country analysis and a firm analysis, thus allowing to widen the study and delve deeper into the use of econometric instruments. More specifically, in the first empirical stage both static (Fixed Effects) and dynamic (LSDV Corrected) methodologies have been implemented, whereas in the second stage the Cox Proportional Function has been chosen in order to handle with censored data.

La città divisa. Conflittualità, confini, prove di comunità

Il presente lavoro approfondisce le tematiche della conflittualità e della separazione etnica, sociale, religiosa, generazionale e culturale. In particolare, riporta i risultati di ricerche condotte in alcuni degli attuali contesti urbani più carichi di tensioni conflittuali, cercando di individuare i motivi vicini e remoti del confligere, le attività messe in atto per contenere le tensioni e le relative necessità educative poste in primo piano. L’elaborato si compone di cinque parti. La prima parte consiste in una riflessione teorica sulle dinamiche che caratterizzano le interazioni sociali nello spazio cittadino. Nella seconda parte viene trattato il tema del settarismo in Scozia, che vede contrapposti i cattolici di origine irlandese (generalmente tifosi della squadra di calcio dei Celtic) e i protestanti di sangue scozzese (generalmente tifosi dei Rangers). La terza parte ricostruisce la storia e il presente della lunga convivenza tra tatari musulmani e russi cristiano-ortodossi nei territori dell’attuale Repubblica etnica del Tatarstan, situata nel cuore della Russia europea, ponendo particolare attenzione agli aspetti religiosi, linguistici, culturali ed educativi. La quarta parte parla del disagio nelle periferie europee, manifestatosi in modo eclatante con le rivolte giovanili in Francia (2005) e nel Regno Unito (2011). La parte conclusiva, infine riprenderà alcuni degli elementi emersi per proporre una riflessione di tipo pedagogico atta ad affrontare in tutta la sua complessità, e con approcci nuovi, il tema della città divisa, con le relative conflittualità, i confini e le prove di comunità.

Evaluation of Human Exposure to Magnetic Fields Generated by Electric Power Systems in Complex Configurations

The international growing concern for the human exposure to magnetic fields generated by electric power lines has unavoidably led to imposing legal limits. Respecting these limits, implies being able to calculate easily and accurately the generated magnetic field also in complex configurations. Twisting of phase conductors is such a case. The consolidated exact and approximated theory regarding a single-circuit twisted three-phase power cable line has been reported along with the proposal of an innovative simplified formula obtained by means of an heuristic procedure. This formula, although being dramatically simpler, is proven to be a good approximation of the analytical formula and at the same time much more accurate than the approximated formula found in literature. The double-circuit twisted three-phase power cable line case has been studied following different approaches of increasing complexity and accuracy. In this framework, the effectiveness of the above-mentioned innovative formula is also examined. The experimental verification of the correctness of the twisted double-circuit theoretical analysis has permitted its extension to multiple-circuit twisted three-phase power cable lines. In addition, appropriate 2D and, in particularly, 3D numerical codes for simulating real existing overhead power lines for the calculation of the magnetic field in their vicinity have been created. Finally, an innovative ‘smart’ measurement and evaluation system of the magnetic field is being proposed, described and validated, which deals with the experimentally-based evaluation of the total magnetic field B generated by multiple sources in complex three-dimensional arrangements, carried out on the basis of the measurement of the three Cartesian field components and their correlation with the field currents via multilinear regression techniques. The ultimate goal is verifying that magnetic induction intensity is within the prescribed limits.

Essays on Innovative Activity and the Protection of Innovations

This dissertation looks at three widely accepted assumptions about how the patent system works: patent documents disclose inventions; this disclosure happens quickly, and patent owners are able to enforce patents. The first chapter estimates the effect of stronger trade secret protection on the number of patented innovations. When firms find it easier to protect business information, there is less need for patent protection, and accordingly less need for the disclosure of technical information that is required by patent law. The novel finding is that when it is easier to keep innovations, there is not only a reduction in the number of patents but also a sizeable reduction in disclosed knowledge per patent. The chapter then shows how this endogeneity of the amount of knowledge per patent can affect the measurement of innovation using patent data. The second chapter develops a game-theoretic model to study how the introduction of fee-shifting in US patent litigation would influence firms’ patenting propensities. When the defeated party to a lawsuit has to bear not only their own cost but also the legal expenditure of the winning party, manufacturing firms in the model unambiguously reduce patenting, with small firms affected the most. For fee-shifting to have the same effect as in Europe, the US legal system would require shifting of a much smaller share of fees. Lessons from European patent litigation may, therefore, have only limited applicability in the US case. The third chapter contains a theoretical analysis of the influence of delayed disclosure of patent applications by the patent office. Such a delay is a feature of most patent systems around the world but has so far not attracted analytical scrutiny. This delay may give firms various kinds of strategic (non-)disclosure incentives when they are competing for more than a single innovation.

Il valore precettivo dei diritti sociali fondamentali previsti dal titolo IV della Carta

Il dibattito giuridico, politico ed economico in tema di protezione dei diritti sociali nel contesto del processo di integrazione europea risale alle origini stesse di tale processo. A circa dieci anni dall’attribuzione alla Carta dei diritti fondamentali dell’UE dello stesso valore giuridico dei Trattati, sembra possibile tracciare un primo bilancio in termini di aspettative inverate ed aspettative non soddisfatte quanto alla giustiziabilità dei diritti sociali fondamentali contenuti nel Titolo IV direttamente o indirettamente al rapporto di impiego (articoli da 27 a 34). A questo fine, la tesi ha adottato una struttura tripartita capace di coniugare una metodologia di analisi pratica, in relazione alla giurisprudenza della Corte di giustizia UE post Lisbona (Capitolo III), con un’analisi dal carattere maggiormente teorico-ricostruttivo (Capitoli I e II). La ricerca cerca di dimostrare come tanto i più interessanti sviluppi quanto i limiti registratisi nella giurisprudenza della CGUE (rispettivamente, l’efficacia diretta, anche orizzontale, di alcuni di essi negli ordinamenti nazionali, e la determinazione del loro ambito di applicazione e delle modalità di interazione con il diritto secondario e primario) possano essere meglio compresi tenendo in debito conto il percorso ed il significato di ciascuno di tali diritti nel contesto del processo di integrazione europea. In breve, si sostiene che la “costituzionalizzazione” dei diritti sociali in esame abbia certamente un “valore aggiunto” che, tuttavia, riflette la natura sui generis e le finalità dell’Unione, il sistema di riparto di competenze tra Stati membri e Unione, ed il significato ultimo del sistema UE di tutela dei diritti fondamentali. Ciò non toglie che questi caratteri, con il tempo, possano infine mutare.

New perspectives in statistical mechanics and high-dimensional inference

The main purpose of this thesis is to go beyond two usual assumptions that accompany theoretical analysis in spin-glasses and inference: the i.i.d. (independently and identically distributed) hypothesis on the noise elements and the finite rank regime. The first one appears since the early birth of spin-glasses. The second one instead concerns the inference viewpoint. Disordered systems and Bayesian inference have a well-established relation, evidenced by their continuous cross-fertilization. The thesis makes use of techniques coming both from the rigorous mathematical machinery of spin-glasses, such as the interpolation scheme, and from Statistical Physics, such as the replica method. The first chapter contains an introduction to the Sherrington-Kirkpatrick and spiked Wigner models. The first is a mean field spin-glass where the couplings are i.i.d. Gaussian random variables. The second instead amounts to establish the information theoretical limits in the reconstruction of a fixed low rank matrix, the “spike”, blurred by additive Gaussian noise. In chapters 2 and 3 the i.i.d. hypothesis on the noise is broken by assuming a noise with inhomogeneous variance profile. In spin-glasses this leads to multi-species models. The inferential counterpart is called spatial coupling. All the previous models are usually studied in the Bayes-optimal setting, where everything is known about the generating process of the data. In chapter 4 instead we study the spiked Wigner model where the prior on the signal to reconstruct is ignored. In chapter 5 we analyze the statistical limits of a spiked Wigner model where the noise is no longer Gaussian, but drawn from a random matrix ensemble, which makes its elements dependent. The thesis ends with chapter 6, where the challenging problem of high-rank probabilistic matrix factorization is tackled. Here we introduce a new procedure called "decimation" and we show that it is theoretically to perform matrix factorization through it.

Grant-free protocols for massive multiple access

In next generation Internet-of-Things, the overhead introduced by grant-based multiple access protocols may engulf the access network as a consequence of the proliferation of connected devices. Grant-free access protocols are therefore gaining an increasing interest to support massive multiple access. In addition to scalability requirements, new demands have emerged for massive multiple access, including latency and reliability. The challenges envisaged for future wireless communication networks, particularly in the context of massive access, include: i) a very large population size of low power devices transmitting short packets; ii) an ever-increasing scalability requirement; iii) a mild fixed maximum latency requirement; iv) a non-trivial requirement on reliability. To this aim, we suggest the joint utilization of grant-free access protocols, massive MIMO at the base station side, framed schemes to let the contention start and end within a frame, and succesive interference cancellation techniques at the base station side. In essence, this approach is encapsulated in the concept of coded random access with massive MIMO processing. These schemes can be explored from various angles, spanning the protocol stack from the physical (PHY) to the medium access control (MAC) layer. In this thesis, we delve into both of these layers, examining topics ranging from symbol-level signal processing to succesive interference cancellation-based scheduling strategies. In parallel with proposing new schemes, our work includes a theoretical analysis aimed at providing valuable system design guidelines. As a main theoretical outcome, we propose a novel joint PHY and MAC layer design based on density evolution on sparse graphs.