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An investigation of the Ora del Garda wind by means of airborne and surface measurements
No full textOn fair-weather summer days an intense southerly lake breeze blows across the northern shorelines of Lake Garda (Italy). This wind, known as Ora del Garda, arises regularly in the late morning, and then channels northward into the adjacent Sarca Valley and Lakes Valley, coupling with the local up-valley flow. In the early afternoon, after flowing over an elevated (~400 m high) saddle, the Ora del Garda wind breaks into the Adige Valley north of Trento city; there it flows down on the valley floor, interacting with the local up-valley wind and creating a strongly turbulent flow. The characteristic diurnal cycle of surface meteorological variables determined by the lake-valley coupled circulation is rather well-known, on the basis of climatological analyses of data from surface automatic weather stations operated in the area by local institutions; on the contrary, the valley upper atmosphere structure, i.e. the structure of the atmospheric boundary-layer (ABL), associated with the Ora del Garda development has not yet been investigated. Indeed, in such a complex terrain area, the characterization of the typical structure, spatial variation and depth of the ABL, as well as a sound knowledge of local atmospheric circulation patterns, are of crucial importance for the understanding of the local climate and of air pollution transport and dispersion processes.
To meet this lack of knowledge, a series of targeted measurement campaigns, including both intensive surface observations and research flights, were carried out by the Atmospheric Physics Group of the University of Trento in the study area between 1998 and 2001, providing the database for the present work. Five flights of an instrumented motorglider explored specific sections of the valley atmosphere, namely at Lake Garda’s shoreline, in the lower Sarca Valley, in the Lakes Valley, and where the Ora del Garda and the Adige Valley up-valley flow interact. Position, pressure, temperature and relative humidity were measured along spiralling trajectories performed over the above mentioned target areas. Surface observations from a number of weather stations disseminated along the valley floor provided a picture of the diurnal cycles of meteorological quantities determined at the surface by the development of the investigated wind on the flight days.
The preliminary processing of the experimental dataset included the application of a suitable procedure to correct airborne temperature data for the time-delay effect induced by the slow-response behavior of the sensor, and required the determination of a proper time constant. The dominant vertical structure of the valley ABL was then deciphered on the basis of vertical “pseudo-soundings” (i.e. mean vertical profiles) of potential temperature and water vapour mixing ratio extracted from airborne data. Shallow mixed layers, surmounted by deeper stable layers, likely to be produced by local subsidence associated with up-slope flows, were detected up-valley. This characteristic pattern is indeed in good accord with ABL structures typically observed in deep Alpine valleys in connection with up-valley winds, as reported in the literature. On the other hand, closer to the lake the potential temperature profile was typically stabilized down to lower heights, due to the onshore advection of colder air from above the water surface.
A residual kriging (RK) technique was adopted to map potential temperature fields over 3D high-resolution grids for each explored section of the valley atmosphere, integrating both surface and airborne observations. Exploiting a test-bed database, RK method was preliminarly tested against the interpolation methods commonly used in the literature for mapping airborne data, namely inverse distance, inverse squared distance and natural neighbor methods. The predictive performance of the different methods was assessed by means of a cross-validation procedure, and a critical comparison of the different interpolation results was carried out. Finally, RK resulted the best-performing technique for the specific application.
RK-interpolated fields revealed fine-scale local features of the complex ABL thermal structures determined by the Ora del Garda in the study area valleys, revealing at the same time macroscopic features of the thermo-topographically driven wind field, mainly amenable to irregular topography and land cover heterogeneities. In particular, a non-homogeneous penetration of the lake-breeze front across the flat basin facing Lake Garda was detected in the morning, while in the afternoon the presence of a sharp discontinuity in the upper-level vertical stratification, originated by updrafts and downdrafts associated with the lake breeze circulation, was observed. Moreover, a strongly asymmetric potential temperature field, resulting from the contrast between the stable core of the Ora del Garda up-valley flow and an intense up-slope flow layer developing along a bare-rock valley sidewall, was detected in the area of Cavedine Lake in the Lakes Valley. Further up-valley, RK-interpolated fields displayed a thermal structure compatible with the occurrence of a single-cell cross-valley circulation, likely to be originated by asymmetric solar irradiation and by the local valley curvature. The valley curvature was also found to induce a preferential channeling of the up-valley flow along the northwestern sidewall at the valley end, in proximity of the elevated saddle from where the Ora del Garda overflows into the underlying Adige Valley, giving origin to an anomalous, strong katabatic wind that hinders the regular development of the local up-valley wind in the area north of Trento. Here the westerly inflow from the Lakes Valley feeds a denser wedge of potentially cooler air, which forces the local up-valley (i.e. southerly) wind to flow over it. Regridded potential temperature fields provided further insight into this flow pattern, revealing the occurrence in the area of a hydraulic jump structure, due to the blocking exerted on the flow by the eastern Adige Valley sidewall. This induced a pronounced deepening of the local mixed layer, which was likely produced by the highly-turbulent flow conditions that usually develop here following the Ora del Garda outbreak
On structure and decoding of Hermitian codes
No full textGiven a linear code, it is important both to identify fast decoding algorithms and to estimate the rst terms of its weight distribution. Ecient decoding algorithms allow the exploitation of the code in practical situations, while the knowledge of the number of small-weight codewords allows to estimate its decoding performance. For ane-variety codes and its subclass formed by Hermitian codes, both problems are as yet unsolved. We investigate both and provide some solutions for special cases of interest.
The rst problem is faced with use of the theory of Gröbner bases for zero-dimensional ideals.
The second problem deals in particular with small-weight codewords of high-rate Hermitian codes. We determine them by studying some geometrical properties of the Hermitian curve, specically the intersection number of the curve with lines and parabolas
Silicon Concentrator Solar Cells: Fabrication, Characterization and Development of Innovative Designs
No full textThis work presents the design, realization and characterization of high efficiency Silicon photovoltaic cells for concentration applications.
In order to develop high efficient Si concentrator solar cells two different ways have been followed. The first one aims to optimize the design and the fabrication process of a conventional front-side contacted cell, based on a planar n-p junction. Although this cell structure is rather simple and cheap to produce, we show that a conversion effciency higher than 23% can be reached under concentrated light, if the cell design and the fabrication process are suitably optimized. The second way aims to investigate and propose completely new cell designs which use some 'three-dimensional' structures, such as deep-grooved contacts and through-silicon vertical connections. The new cell designs allow to overcome some intrinsic limits of the conventional front-side contacted cells and could be worthwhile to improve the conversion eciency in future real applications
Functional characterization of the RNA binding protein RALY
No full textOf 25000 genes encoded from genome, more than 90% are subject to alternative splicing or other post-transcriptional modifications. All these events produce a high number of different proteins that form the basis for the high variety of cells. The RNAbinding proteins (RBPs) play crucial roles in this variability by regulating many steps of biological processes regarding RNA metabolism. The heterogeneous nuclear ribonucleoproteins (hnRNPs) belong to big family of RBPs involved in many aspects of RNA metabolism including RNA stability, intracellular transport and translation. More recently, RALY, a RNA-binding protein associated with the lethal yellow mutation in mouse, has been identified as new member of the hnRNP family even if, its biological function remains still elusive.
My PhD project aimed to characterize human RALY and to assess its function in mammalian cells. Initially I dentified the expression pattern of this protein into the cell and I characterized the functional nuclear localization sequence that localizes RALY protein into the nuclear compartment. In order to better understand the role of RALY in the cells, I identified the proteins component of RALY-containing complexes using a new assay named iBioPQ (in vivo-Biotinylation-Pulldown-Quant assay). I also performed polyribosome profiling assay to check the resence of RALY in translating mRNAs. Moreover, a microarray assay was performed in order to identify potential mRNAs whose metabolism appears dependent on RALY expression. Taken together, the results that I obtained suggest that RALY is involved in mRNA metabolism. Unfortunately more studies remain to do before shedding some light on the biological
role of RALY in mammal
Multimodal Personality Recognition from Audiovisual Data
No full textAutomatic behavior analysis lies at the intersection of different social and technical research domains. The interdisciplinarity of the field, provides researchers with the means to study the manifestations of human constructs,
such as personality. A branch of human behavior analyis, the study of personality provides insight into the cognitive and psychological construction of the human being. Research in personality psychology, advances in com-
puting power and the development of algorithms, have made it possible to analyze existing data in order to understand how people express their own personality, perceive others’, and what are the variables that influence its manifestation.
We are pursuing this line of research because insights into the personality of the user can have an impact on how we interact with technology. Incorporating research on personality recogniton, both from a cognitive as well
as an engineering perspective, into computers could facilitate the interactions between humans and machines. Previous attempts on personality recognition have focused on a variety of different corporas (ranging from text to audiovisual data), different scenarios (interviews, meetings), different channels of communication (audio, video, text) and different subsets of personality traits (out of the five ones present in the Big Five Model:
Extraversion, Agreeableness, Conscientiousness, Emotional Stability and Creativity). Our work builds on previous research, by considering simple acoustic and visual non-verbal features extracted from multimodal data, but doesn’t fail to bring novelties: we consider previously uninvestigated scenarios, and at the same time, all of the five personality traits and not just a subset
Traits, States and Situations: Automatic Prediction of Personality and Situations from Actual Behavior
No full textTechnology has a great impact on our everyday lives; computers, smart devices, sensors and digital
technology in general, try to communicate with us to accomplish some task. Each step of the communication
however, requires understanding of the future behavioral utterance, deciding on what is
the circumstance and the social context, and finally predicting the individual’s needs. Even if computers
are so deeply involved in our daily lives, they lack basic social skills that would allow for
natural communication. We believe automatic personality recognition will provide computers with
an essential social notion, improving the quality of services, such as in intelligent tutoring systems
or information retrieval systems among many other uses. Over the past few years, researcher in
social computing have shown that personality trait recognition from nonverbal behavior is feasible,
yet, the accuracy rate never exceeds a certain level, due to a phenomenon called within-person
variability. This means that individuals may vary their behavioral manifestation according to the
situational context in which they are in. In this thesis, we propose a shift from the traditional
personality trait theory, to an approach which incorporates the personality fluctuations. This new
perspective defines personality as dynamic episodes, the so called personality states, which relate
to situational factors. Based on this property, we define the notion of social situations and propose
a fully data-driven approach based on the Topic Modeling theory. The active situational characteristics
that emerge from the model are interpreted according to their interrelation to the personality
states fluctuations. We also present an automatic framework based on topic modeling, which handles
dynamic spatio-temporal patterns of behavior and aims to predict the semantic meaning of the
situational patterns, in meaningful situations, without the need of expert annotators
L'eroe satirico di Luciano tra Aristofane e Platone
No full textTra le caratteristiche costitutive della produzione di Luciano di Samosata, la mixis è una dimensione fondamentale, attiva a vari livelli. Fra questi rientra anche la caratterizzazione dei protagonisti dei dialoghi e, in particolar modo, dei personaggi satirici, portavoce del messaggio autoriale e, per ciò stesso, in parte ma non totalmente identificabili con Luciano. L'analisi di queste figure mostra come gli archetipi comico, platonico e menippeo (identificati come tali dall'autore in Bis acc. 33) intervengano nella creazione del personaggio satirico, non senza una certa continuità. Allo stesso tempo, questa non si piega, però, a facili categorizzazioni, in linea con l'intera produzione lucianea
Effective Analysis, Characterization, and Detection of Malicious Activities on the Web
No full textThe Web has evolved from a handful of static web pages to billions of dynamic and interactive web pages. This evolution has positively transformed the paradigm of communication, trading, and collaboration for the benefit of humanity. However, these invaluable benefits of the Web are shadowed by cyber-criminals who use the Web as a medium to perform malicious activities motivated by illegitimate benefits. Cyber-criminals often lure victims to visit malicious web pages, exploit vulnerabilities on victims’ devices, and then launch attacks that could lead to: stealing invaluable credentials of victims, downloading and installation of malware on victims’ devices, or complete compromise of victims’ devices to mount future attacks. While the current state-of-the-art is to detect malicious web pages is promising, it is yet limited in addressing the following three problems. First, for the sake of focused detection of certain class of malicious web pages, existing techniques are limited to partial analysis and characterization of attack payloads. Secondly, attacker-motivated and benign evolution of web page artifacts have challenged the resilience of existing detection techniques. The third problem is the prevalence and evolution of Exploit Kits used in spreading web-borne malware. In this dissertation, we present the approaches and the tools we developed to address these problems. To the address partial analysis and characterization of attack payloads, we propose a holistic and lightweight approach that combines static analysis and minimalistic emulation to analyze and detect malicious web pages. This approach leverages features from URL structure, HTML content, JavaScript executed on the client, and reputation of URLs on social networking websites to train multiple models, which are then used in confidence-weighted majority vote classifier to detect unknown web pages. Evaluation of the approach on a large corpus of web pages shows that the approach not only is precise enough in detecting malicious web pages with very low false signals but also does detection with a minimal performance penalty. To address the evolution of web page artifacts, we propose an evolution-aware approach that tunes detection models inline with the evolution of web page artifacts. Our approach takes advantage of evolutionary searching and optimization using Genetic Algorithm to decide the best combination of features and learning algorithms, i.e., models, as a function of detection accuracy and false signals. Evaluation of our approach suggests that it reduces false negatives by about 10% on a fairly large testing corpus of web pages. To tackle the prevalence of Exploit Kits on the Web, we first analyze source code and runtime behavior of several Exploit Kits in a contained setting. In addition, we analyze the behavior of live Exploit Kits on the Web in a contained environment. Combining the analysis results, we characterize Exploit Kits pertinent to their attack-centric and self-defense behaviors. Based on these behaviors, we draw distinguishing features to train classifiers used to detect URLs that are hosted by Exploit Kits. The evaluation of our classifiers on independent testing dataset shows that our approach is effective in precisely detecting malicious URLs linked with Exploit Kits with very low false positives
Experimental models of Elastic Structures: Tensile Buckling and Eshelby-like Forces
No full textMechanical models have been invented, designed and realized to experimentally confirm unexpected behaviours theoretically predicted in elasticity:
- instabilities and bifurcations occurring in structures under ‘tensile dead load’ and the influence of the constraint’s curvature;
- the presence of an ‘Eshelby-like’ or ‘configurational’ force in structures with movable constraints.
Furthermore, ‘classical’ features in elasticity have been substantied by testing small-scale models and observing:
- linearity in the mechanical response of a truss-structure, confirming the usual assumption of linear elasticity when small displacements are considered;
- stress singular fields near stiff quadrilateral inclusions embedded in a ‘soft’ elastic plate, validating the model of rigid inclusion.
All the experiments have been performed at the Laboratory for Physical Modeling of Structures and Photoelasticity of the Department of Civil,Environmental and Mechanical Engineering of the University of Trento
La capacità nel processo. Profili statici e dinamici
No full textIl presente studio è un’indagine “a tutto tondo” sul tema della capacità processuale, che tocca tutti i suoi principali profili d’interesse: la sua definizione e il suo legame con la capacità di diritto sostanziale; la distinzione che essa opera fra soggetti “capaci” e soggetti “incapaci”; le funzioni che essa svolge all’interno del processo e il modo in cui la sua assenza o il suo difetto ne condizionano lo svolgimento; le peculiarità che presenta come thema probandum e come oggetto di decisione in mancanza di prove. L’attenzione che questi molteplici aspetti hanno ricevuto nel nostro ordinamento (sia da parte del legislatore, sia da parte degli interpreti) è piuttosto scarsa: a parte un certo interesse rivolto alla capacità come species del genus “presupposti processuali”, nonché come termine di paragone della capacità di agire di diritto sostanziale all’interno del processo, gli altri profili di rilievo appaiono, tutt’oggi, terreni inesplorati.
Nell’ordinamento processuale tedesco, invece, la capacità processuale (Prozessfähigkeit) non solo è stata disciplinata in maniera più complessa e completa nel diritto positivo, ma soprattutto è stata oggetto di un ampio e approfondito dibattito dottrinale – dibattito che ha riguardato tutti i profili d’interesse del tema in questione e che, valicate le disposizioni e le ripartizioni stabilite dal diritto positivo, ha coinvolto i principi fondamentali cui l’argomento si ricollega e gli interessi che esso sottende.
Il modus procedendi della presente indagine consiste nel sottoporre a un confronto i due differenti approcci (quello italiano e quello tedesco) all’istituto in esame, ripercorrendo uno dopo l’altro i diversi profili di rilievo menzionati; l’obiettivo è quello di osservare come sono risolti, in Germania, i problemi e gli interrogativi sulla capacità processuale che nel nostro ordinamento non trovano una risposta adeguata; il fine ultimo è quello di ricavarne spunti e direttive di riflessione utili all’interprete italiano per tentare di colmare le lacune che, nel nostro sistema processuale, il tema della capacità presenta