1731 research outputs found
Sort by
La "Prima" e la "Seconda Oratione" di Angelo Beolco il Ruzante: edizione critica e commento
Get PDFIl presente lavoro propone una nuova edizione critica commentata delle due orazioni ruzantiane. A un'analisi introduttiva delle due operette, che ne circostanzia temi e occasione di recita, segue il testo criticamente rivisto delle orazioni, accompagnato da una traduzione di servizio e da un commento continuo e puntuale al testo, che mira a enuclearne il significato e i rimandi intertestuali; nella successiva "Nota al testo" si descrive il testimoniale completo, manoscritto e a stampa, delle due tradizioni, per poi procedere alla ricostruzione dei rapporti fra i testimoni e alla scelta del testo-base dell'edizione, di cui vengono individuate e corrette le mende; si stila in seguito un apparato delle varianti di tipo negativo. Concludono il lavoro l'illustrazione dei criteri di edizione e una nota bibliografica
Scalable Safety and Reliability Analysis via Symbolic Model Checking: Theory and Applications
No full textAssuring safety and reliability is fundamental when developing a safety critical system. Road, naval and avionic transportation; water and gas distribution; nuclear, eolic, and photovoltaic energy production are only some examples where it is mandatory to guarantee those properties. The continuous increasing in the design complexity of safety critical system calls for a never ending sought of new and more advanced analytical techniques. In fact, they are required to assure that undesired consequences are highly improbable. In this Thesis we introduce a novel methodology able to raise the bar in the area of automated safety and reliability analysis. The proposed approach integrates a series of techniques, based on symbolic model checking, into the current development process of safety critical systems. Moreover, our methodology and the resulting techniques are thereafter applied to a series of real-world case studies, developed in collaboration with authoritative entities such as NASA and the Boeing Company
Al- 'Eizariyah and the Wall: from the quasi-capital of Palestine to an Arab Ghetto. The Impact of the Separation Wall on the Social Capital of the Palestinians in East Jerusalem and the West Bank
No full textThis doctoral thesis is about the study of the social capital, its effects on the local development and on the socio-economic resilience of the Palestinians trapped in the East Jerusalem's al-'Eizariyah area. The transformation of al-'Eizariyah since 2002 through the Israeli encroachment on Palestinian land by instrumental use of the Separation Wall policies was analysed and re-state through the lenses of the sociological theory and concepts. Based on the accounts of life stories and interviews with various members of the al-'Eizariyah's former and present community and through the visual data of the changes in al-'Eizariyah and the areas adjacent to the Separation Wall a study of the Palestinian coping and survival strategies was undertaken. The thesis demonstrates how the reality of al-'Eizariyah was changed dramatically in the last two decades despite and in the opposite direction of the Oslo Accords of 1993. To be sure, al-‘Eizariyah, which is located two miles east of Jerusalem, had expanded to adjust to the economic boom of the early post-Oslo years coupled with the political expectations of it being part of the future Palestinian capital. This was disrupted by the failure of the Oslo Accords, and the construction of the Israeli Separation Wall in 2002, which served as an instrument of intimidation and harassment to make Palestinians leave Jerusalem, as this thesis demonstrates. The Wall did not only cut off al-'Eizariyah from the main road that used to connect East Jerusalem to Jericho. The Wall's more sinister and long-term damage has been in the physical and psychological isolation of al-‘Eizariyah and in preventing its residents from being fully integrated in the economic, social, cultural, and political life of the East Jerusalem and of the West Bank. This two-sided effect of the Separation Wall started when most of the people who used to work in East Jerusalem and Israel lost their Jobs, students could no longer study in Jerusalem and had to change schools; the sick no longer could use the healthcare facilities, etc. Former residents of al-'Eizariyah could no longer do any of these basic necessities neither their shopping and entertainment in Jerusalem freely without being humiliated with denial of access to Jerusalem based on the persons' ability to present a Blue ID at the checkpoint, the only ID that is recognized by the Israeli regime. While some social capital forms helped in coping with the difficulties caused by this new reality it was the difference in the pre- and post-Wall situations that were examined in order to understand the impact of the adversity represented by the Wall on the social capital of the Palestinians. The purpose of this thesis is to demonstrate the implications of the construction of the Wall on the socio-economic life of al-‘Eizariyah residents and to study the Israel-Palestine conflict from sociological lens using a case study setting and qualitative analysis approach. This thesis demonstrates positive impact of the Wall on social capital types by where the bonding social capital became stronger yet the trend got reversed. At the community level, the challenges were too large to be handled only by bonding social capital. Therefore, there is a combined effort between the Palestinian Authority (PA) and the local civil society associations and the private sector to overcome problems related to education, health care services, trade and labour in addition to social security caused by the Wall. It was found that bridging social capital and linking social capital were strongly present after the Wall was completed. Although civil society associations are strongly present in al-‘Eizariyah but because the Palestinian society is structured along patrimonial, familial, clannish, tribal and contradictory geographical cleavages, most of these associations work in a way that transformed the intended outcome of bridging social capital to some kind of bonding social capital as the beneficiaries and the participants are mostly from their family, clan members, or those who belong to the same political party, and not the community as a whole. However, observations and the empirical evidence show that bonding is stronger than bridging social capital. The social fragmentation caused by several social forces such as the local-stranger relationship, between the locals of al-‘Eizariyah and the displaced residents, prevented efficient cooperation in solving community problems. Lack of the sense of belonging is not only because the locals always express superiority over the displaced, but also because the displaced themselves do not want to lose their rooted original identity, especially the refugees who settled in the town after the 1948 war. This had a great overall impact on the unity of the Palestinian society especially that ‘the refugees’ communities constitute approximately 42 percent of the total population of the West Bank.
The future challenge of the Palestinians in areas such as al-‘Eizariyah is to find ways of detecting de-fragmentation and manipulation policies and develop strategies that would prevent de-fragmentation of the Palestinians being orchestrated by the Israeli Wall policies and that only become apparent with a time lapse when it can be too late
Holistic Security Requirements Engineering for Socio-Technical Systems
No full textSecurity has been a growing concern for large organizations, especially financial and gov- ernmental institutions, as security breaches in the systems they depend have repeatedly resulted in losses of billions per year, and this cost is on the rise. A primary reason for these breaches is the “socio-technical” nature of today’s systems that consist of an amal- gam of social and human actors, processes, technology and infrastructure. We refer to such systems as Socio-Technical Systems (STSs). Finding secure solutions for STSs is a difficult and error-prone task because of their heterogeneity and complexity. The thesis proposes a holistic security requirements analysis framework which catego- rizes system security concerns into three layers, including a social layer (social actors and business processes), a software layer (software applications that support the social layer) and an infrastructure layer (physical infrastructure, hardware, and devices). Within each layer, security requirements are elicited, and security mechanisms are designed to satisfy the security requirements. In particular, a cross-layer support link is defined to capture how security mechanisms deployed at one layer influence security requirements of the next layer down, allowing us to systematically and iteratively analyze security for all three layers and eventually produce holistic security solutions for the systems. To ensure the quality of the analysis of our approach and to promote practical adoption of the three-layer approach, the thesis includes two additional components. Firstly, we propose a holistic attack analysis, which takes an attacker’s perspective to explore realistic attacks that can happen to a system and thus contributes to the identification of critical security requirements. This approach consists of an attack strategy identification method which analyzes attacker’s alternative malicious intentions, and an attack strategy operationalization method which analyzes realistic attack actions that can be performed by attackers. Secondly, the thesis proposes a systematic approach for selecting and applying security patterns, which describe proven security solutions to known security problems. As such, analysts with little security knowledge can efficiently leverage reusable security knowledge to operationalize security requirements in terms of security mechanisms. This approach also allows us to systematically analyze and enforce the impact of deployed security mechanisms on system functional specifications. We have developed a prototype tool, which implements the formalized analysis methods of our three-layer framework and enables the semi-automatic application of our proposal. With the help of the tool, we apply our framework to two large-scale case studies so as to validate the efficacy of our approach
A Programmable Enforcement Framework for Security Policies
No full textThis thesis proposes the MAP-REDUCE framework, a programmable framework, that can be used to construct enforcement mechanisms of different security policies. The framework is based on the idea of secure multi-execution in which multiple copies of the controlled program are executed. In order to construct an enforcement mechanism of a policy, users have to write a MAP program and a REDUCE program to control inputs and outputs of executions of these copies. This thesis illustrates the framework by presenting enforcement mechanisms of non-interference (from Devriese and Piessens), non-deducibility (from Sutherland) and deletion of inputs (a policy proposed by Mantel). It demonstrates formally soundness and precision of these enforcement mechanisms. This thesis also presents the investigation on sufficient condition of policies that can be enforced by the framework. The investigation is on reactive programs that are input total and have to finish processing an input item before handling another one. For reactive programs that always terminate on any input, non-empty testable hypersafety policies can be enforced. For reactive programs that might diverge, non-empty downward closed w.r.t. termination policies can be enforced
Rolling-Ball Rubber-Layer system for the lightweight structures seismic protection: experimentation and numerical analyses
No full textProtection of high-value building contents from seismic damage represents a worldwide challenging task. Artefacts, sophisticated medical and electrical equipment, high performance computer installations and other special contents have shown, in the last years, their high vulnerability both for high and moderate earthquakes. The lack of effective techniques, sufficiently developed for seismic risk mitigation of such objects, makes the seismic protection of contents a crucial issue. An effective means to provide this protection is seismic isolation. The isolation techniques to be used for the content are not a mere extension of the ones used for civil structures, although the basic theories and concepts of seismic isolation are the same. Indeed, the following technical peculiarities have to be considered: the contents have masses orders of magnitude smaller than those characteristic of civil structures and, secondly, they are often very vulnerable and are not able to withstand even small seismic actions. This thesis, that fits into this context, presents an innovative seismic isolation device for lightweight structures, named “RBRL” system, i.e. “Rolling-Ball Rubber-Layer”, and it is aimed at studying the dynamic behaviour of the system itself through numerical analyses and parametric experimentations, with the goals to get a sufficient comprehension of the system performance and its general numerical characterization. The device, invented by Alan Thomas at TARRC (“Tun Abdul Razach Research Centre”) comprises: a rolling-based bearing system, which allows any displacements in the horizontal plane; two rubber layers bonded to the steel tracks, which give an adequate damping to the rolling steel balls; some rubber springs, which ensure the recentering of the system through their elastic stiffness
Die (Un)Verhältnismäßigkeit der Strafe: eine Vergleichende Untersuchung Anhand Konkreter Fälle
No full textNel presente lavoro è stato approfondito il ruolo del principio di proporzionalità nel campo delle sanzioni, attraverso un confronto con il sistema penale tedesco e con i principi derivanti dal piano sovranazionale. Partendo da un’analisi dei fondamenti giuridico-filosofici del principio in questione, si è voluto mettere in evidenza la fungibilità dello stesso nelle argomentazioni di posizioni teoriche anche distanti tra loro. Minimo comun denominatore di tali impostazioni risiede nell’attribuzione alla nozione di proporzionalità del concetto di giustizia e razionalità. Nel prosieguo della trattazione si è analizzato il ruolo del principio di proporzionalità all’interno del sistema giuridico italiano, ed in particolare il ruolo svolto dallo stesso nelle pronunce della Corte Costituzionale, ove il concetto di proporzionalità viene adoperato quale sinonimo di ragionevolezza. Rimanendo sul piano delle pronunce di costituzionalità sulle pene, si è analizzata la nozione di proporzionalità quale ultima ratio del diritto penale, come elaborata dai tribunali tedeschi, nonché dalla Corte Europea dei diritti dell’uomo. Sebbene al legislatore venga riservato un discreto margine di discrezionalità nel campo della scelta dei comportamenti da punire (come mostrano i casi dell’incesto e della preparazione di un grave atto violento idoneo a mettere pericolo l’integrità dello stato), la possibilità di svolgere il controllo prima di proporzionalità in senso ampio (ove si valuti l’idoneità e la necessarietà della norma penale rispetto ad un determinato scopo di tutela) e poi di proporzionalità in senso stretto (ove si valuti l’opportunità in sé della “intromissione” del legislatore, rispetto alla lesione di diritti che ne consegue) fa sì che l’esame della proporzionalità si possa riempire di sostanza e pertanto se ne delineano le caratteristiche che lo renderebbero percorribile anche nel sistema italiano. Di seguito viene maggiormente sviluppata la nozione di proporzionalità quale sproporzionalità della pena nell’ordinamento tedesco, ovvero nella sua accezione negativa. In sede di Strafzumessung un giudizio di proporzionalità nel senso del raggiungimento di quel perfetto rapporto tra colpa del reo, gravità del fatto di reato e quantum di pena rischia di fallire: molto più spesso la proporzionalità viene infatti ad essere meglio definita attraverso il ricorso alla sua accezione negativa, della sproporzionalità della pena, nel senso della sua insopportabilità. Tale nozione potrebbe costituire il parametro per un giudizio – da far valere in sede di esame di legittimità e di costituzionalità – sulla plausibilità delle pene già commisurate. Sul piano sovranazionale il concetto di sproporzionalità della pena si arricchisce di un ulteriore significato: il riferimento alla nozione di “inumanità” della stessa. Prendendo le mosse dall’art. 49 della Carta dei diritti fondamentali dell’Unione Europea in base al quale la pena non deve essere sproporzionata rispetto al reato, si giunge all’analisi dell’interpretazione più recente della Corte europea dei diritti dell’uomo in tema di ergastolo senza possibilità di liberazione anticipata, dove il giudizio di manifesta sproporzionalità della pena viene ancorato all’art. 3 della Convenzione europea dei diritti dell’uomo
Essays on the demand and supply of small business finance
No full textThis PhD dissertation is a collection of four essays focusing on the demand and supply of small business finance in Kenya. The studies are the result of primary research conducted over three years with both demand-side players, more specifically micro and small-scale entrepreneurs operating in a low-income area in Nairobi. And the main suppliers of small businesses finance in Kenya - commercial banks - which provided data on the size, characteristics and evolution of their SME finance portfolio between 2009 and 2013. Since commercial banks are not the only players in the provision of finance to small firms, the dissertation studies the entire financial landscape of both formal and informal financial providers, including institutions such as microfinance institutions, savings groups and moneylenders among others. The dissertation is divided in two parts: the first half of the dissertation analyses the determinants, effects and challenges of access to formal and informal finance by small enterprises in Nairobi (Essays 1 and 2). These two essays use primary data collected through a survey questionnaire with 344 micro and small enterprises in a low income neighbourhood in Nairobi. The analysis describes the financial landscapes in which businesses operate and the effects of access to credit on firm performance (e.g. investments, profitability and employment growth.). The second half of the dissertation analyses the supply-side, more specifically the relation between formal financial sector development and economic growth (Essay 3) and the characteristics and development of bank financing to SMEs (small and medium enterprises) in Kenya (Essay 4). Essay 3 relies on secondary time-series data taken from the World Bank databases, whereas Essay 4 uses original survey data administered to commercial banks in Kenya in two survey rounds in 2012 and 2014. Each essay in this dissertation is a standalone study with its own literature survey, research questions, data and methodological approach. The main findings of the demand-side chapters is that informality has significant effects on access (or exclusion) to bank finance, but is less relevant when we investigate informal financial instruments such as self-help groups and family/friend loans. Essay 2 of the dissertation shows that different types of loans have different effects on the performance of businesses, and that loans from commercial banks seem to incentivize investments and employment creation more than other types of loans. The supply-side chapters on the other hand show that there is a long-term association between financial sector development in Kenya and economic growth, and that there is a reciprocal relation of causality over the long-run. Finally, Essay 4 shows that bank financing to SMEs has grown steadily over the last few years and that banks are increasingly exposed to small businesses in their lending portfolio. However, the financial products to SMEs tend to be unsophisticated and concentrated in few sectors
Modelling input texts: from Tree Kernels to Deep Learning
No full textOne of the core questions when designing modern Natural Language Processing (NLP) systems is how to model input textual data such that the learning algorithm is provided with enough information to estimate accurate decision functions. The mainstream approach is to represent input objects as feature vectors where each value encodes some of their aspects, e.g., syntax, semantics, etc. Feature-based methods have demonstrated state-of-the-art results on various NLP tasks. However, designing good features is a highly empirical-driven process, it greatly depends on a task requiring a significant amount of domain expertise. Moreover, extracting features for complex NLP tasks
often requires expensive pre-processing steps running a large number of linguistic tools while relying on external knowledge sources that are often not available or hard to get. Hence, this process is not cheap and often constitutes one of the major challenges when attempting a new task or adapting to a different language or domain.
The problem of modelling input objects is even more acute in cases when the input examples are not just single objects but pairs of objects, such as in various learning to rank problems in Information Retrieval and Natural Language processing. An alternative to feature-based methods is using kernels which are essentially non-linear functions mapping input examples into some high dimensional space thus allowing for learning decision functions with higher discriminative power. Kernels implicitly generate a very large number of features computing similarity between input examples in that implicit space. A well-designed kernel function can greatly reduce the effort to design a large set of manually designed features often leading to superior results. However, in the recent years, the use of kernel methods in NLP has been greatly under-estimated primarily due to the following reasons: (i) learning with kernels is slow as it requires to carry out optimization in the dual space leading to quadratic complexity; (ii) applying kernels to the input objects encoded with vanilla structures, e.g., generated by syntactic parsers, often yields minor improvements over carefully designed feature-based methods.
In this thesis, we adopt the kernel learning approach for solving complex NLP tasks and primarily focus on solutions to the aforementioned problems posed by the use of kernels. In particular, we design novel learning algorithms for training Support Vector Machines with structural kernels, e.g., tree kernels, considerably speeding up the training over the conventional SVM training methods. We show that using the training algorithms developed in this thesis allows for training tree kernel models on large-scale datasets containing millions of instances, which was not possible before. Next, we focus on the problem of designing input structures that are fed to tree kernel functions to automatically generate a large set of tree-fragment features. We demonstrate that previously used plain structures generated by syntactic parsers, e.g., syntactic or dependency trees, are often a poor choice thus compromising the expressivity offered by a tree kernel learning framework. We propose several effective design patterns of the input tree structures for various NLP tasks ranging from sentiment analysis to answer passage reranking. The central idea is to inject additional semantic information relevant for the task directly into the tree nodes and let the expressive kernels generate rich feature spaces. For the opinion mining tasks, the additional semantic information injected into tree nodes can be word polarity labels, while for more complex tasks of modelling text pairs the relational information about overlapping words in a pair appears to significantly improve the accuracy of the resulting models. Finally, we observe that both feature-based and kernel methods typically treat words as atomic units where matching different yet semantically similar words is problematic. Conversely, the idea of distributional approaches to model words as vectors is much more effective in establishing a semantic match between words and phrases. While tree kernel functions do allow for a more flexible matching between phrases and sentences through matching their syntactic contexts, their representation can not be tuned on the training set as it is possible with distributional approaches. Recently, deep learning approaches have been applied to generalize the distributional word matching problem to matching sentences taking it one step further by learning the optimal sentence representations for a given task. Deep neural networks have already claimed state-of-the-art performance in many computer vision, speech recognition, and natural language tasks. Following this trend, this thesis also explores the virtue of deep learning architectures for modelling input texts and text pairs where we build on some of the ideas to model input objects proposed within the tree kernel learning framework. In particular, we explore the idea of relational linking (proposed in the preceding chapters to encode text pairs using linguistic tree structures) to design a state-of-the-art deep learning architecture for modelling text pairs. We compare the proposed deep learning models that require even less manual intervention in the feature design process then previously described tree kernel methods that already offer a very good trade-off between the feature-engineering effort and the expressivity of the resulting representation. Our deep learning models demonstrate the state-of-the-art performance on a recent benchmark for Twitter Sentiment Analysis, Answer Sentence Selection and Microblog retrieval
Impurities in a Bose-Einstein condensate using quantum Monte-Carlo methods: ground-state properties.
Get PDFIn this thesis we investigate the properties of impurities immersed in a dilute Bose gas at zero temperature using quantum Monte-Carlo methods. The interactions between bosons are modeled by a hard sphere potential with scattering length a, whereas the interactions between the impurity and the bosons are modeled by a short-range, square-well potential where both the sign and the strength of the scattering length b can be varied by adjusting the well depth. We calculate the binding energy, the effective mass and the pair correlation functions of a impurity along the attractive and the repulsive polaron branch. In particular, at the unitary limit of the impurity-bosons interaction, we find that the binding energy is much larger than the chemical potential of the bath signaling that many bosons dress the impurity thereby lowering its energy and increasing its effective mass. We characterize this state by calculating the bosons-boson pair correlation function and by investigating the dependence of the binding energy on the gas parameter of the bosonic bath. We also investigate the ground-state properties of M impurities in a Bose gas at T=0. In particular, the energy and the phase diagram by using both quantum Monte-Carlo and mean field methods