Statistical properties of Radio Halos and the re-acceleration model

Galaxy clusters occupy a special position in the cosmic hierarchy as they are the largest bound structures in the Universe. There is now general agreement on a hierarchical picture for the formation of cosmic structures, in which galaxy clusters are supposed to form by accretion of matter and merging between smaller units. During merger events, shocks are driven by the gravity of the dark matter in the diffuse barionic component, which is heated up to the observed temperature. Radio and hard-X ray observations have discovered non-thermal components mixed with the thermal Intra Cluster Medium (ICM) and this is of great importance as it calls for a “revision” of the physics of the ICM. The bulk of present information comes from the radio observations which discovered an increasing number of Mpcsized emissions from the ICM, Radio Halos (at the cluster center) and Radio Relics (at the cluster periphery). These sources are due to synchrotron emission from ultra relativistic electrons diffusing through µG turbulent magnetic fields. Radio Halos are the most spectacular evidence of non-thermal components in the ICM and understanding the origin and evolution of these sources represents one of the most challenging goal of the theory of the ICM. Cluster mergers are the most energetic events in the Universe and a fraction of the energy dissipated during these mergers could be channelled into the amplification of the magnetic fields and into the acceleration of high energy particles via shocks and turbulence driven by these mergers. Present observations of Radio Halos (and possibly of hard X-rays) can be best interpreted in terms of the reacceleration scenario in which MHD turbulence injected during these cluster mergers re-accelerates high energy particles in the ICM. The physics involved in this scenario is very complex and model details are difficult to test, however this model clearly predicts some simple properties of Radio Halos (and resulting IC emission in the hard X-ray band) which are almost independent of the details of the adopted physics. In particular in the re-acceleration scenario MHD turbulence is injected and dissipated during cluster mergers and thus Radio Halos (and also the resulting hard X-ray IC emission) should be transient phenomena (with a typical lifetime <» 1 Gyr) associated with dynamically disturbed clusters. The physics of the re-acceleration scenario should produce an unavoidable cut-off in the spectrum of the re-accelerated electrons, which is due to the balance between turbulent acceleration and radiative losses. The energy at which this cut-off occurs, and thus the maximum frequency at which synchrotron radiation is produced, depends essentially on the efficiency of the acceleration mechanism so that observations at high frequencies are expected to catch only the most efficient phenomena while, in principle, low frequency radio surveys may found these phenomena much common in the Universe. These basic properties should leave an important imprint in the statistical properties of Radio Halos (and of non-thermal phenomena in general) which, however, have not been addressed yet by present modellings. The main focus of this PhD thesis is to calculate, for the first time, the expected statistics of Radio Halos in the context of the re-acceleration scenario. In particular, we shall address the following main questions: • Is it possible to model “self-consistently” the evolution of these sources together with that of the parent clusters? • How the occurrence of Radio Halos is expected to change with cluster mass and to evolve with redshift? How the efficiency to catch Radio Halos in galaxy clusters changes with the observing radio frequency? • How many Radio Halos are expected to form in the Universe? At which redshift is expected the bulk of these sources? • Is it possible to reproduce in the re-acceleration scenario the observed occurrence and number of Radio Halos in the Universe and the observed correlations between thermal and non-thermal properties of galaxy clusters? • Is it possible to constrain the magnetic field intensity and profile in galaxy clusters and the energetic of turbulence in the ICM from the comparison between model expectations and observations? Several astrophysical ingredients are necessary to model the evolution and statistical properties of Radio Halos in the context of re-acceleration model and to address the points given above. For these reason we deserve some space in this PhD thesis to review the important aspects of the physics of the ICM which are of interest to catch our goals. In Chapt. 1 we discuss the physics of galaxy clusters, and in particular, the clusters formation process; in Chapt. 2 we review the main observational properties of non-thermal components in the ICM; and in Chapt. 3 we focus on the physics of magnetic field and of particle acceleration in galaxy clusters. As a relevant application, the theory of Alfv´enic particle acceleration is applied in Chapt. 4 where we report the most important results from calculations we have done in the framework of the re-acceleration scenario. In this Chapter we show that a fraction of the energy of fluid turbulence driven in the ICM by the cluster mergers can be channelled into the injection of Alfv´en waves at small scales and that these waves can efficiently re-accelerate particles and trigger Radio Halos and hard X-ray emission. The main part of this PhD work, the calculation of the statistical properties of Radio Halos and non-thermal phenomena as expected in the context of the re-acceleration model and their comparison with observations, is presented in Chapts.5, 6, 7 and 8. In Chapt.5 we present a first approach to semi-analytical calculations of statistical properties of giant Radio Halos. The main goal of this Chapter is to model cluster formation, the injection of turbulence in the ICM and the resulting particle acceleration process. We adopt the semi–analytic extended Press & Schechter (PS) theory to follow the formation of a large synthetic population of galaxy clusters and assume that during a merger a fraction of the PdV work done by the infalling subclusters in passing through the most massive one is injected in the form of magnetosonic waves. Then the processes of stochastic acceleration of the relativistic electrons by these waves and the properties of the ensuing synchrotron (Radio Halos) and inverse Compton (IC, hard X-ray) emission of merging clusters are computed under the assumption of a constant rms average magnetic field strength in emitting volume. The main finding of these calculations is that giant Radio Halos are naturally expected only in the more massive clusters, and that the expected fraction of clusters with Radio Halos is consistent with the observed one. In Chapt. 6 we extend the previous calculations by including a scaling of the magnetic field strength with cluster mass. The inclusion of this scaling allows us to derive the expected correlations between the synchrotron radio power of Radio Halos and the X-ray properties (T, LX) and mass of the hosting clusters. For the first time, we show that these correlations, calculated in the context of the re-acceleration model, are consistent with the observed ones for typical µG strengths of the average B intensity in massive clusters. The calculations presented in this Chapter allow us to derive the evolution of the probability to form Radio Halos as a function of the cluster mass and redshift. The most relevant finding presented in this Chapter is that the luminosity functions of giant Radio Halos at 1.4 GHz are expected to peak around a radio power » 1024 W/Hz and to flatten (or cut-off) at lower radio powers because of the decrease of the electron re-acceleration efficiency in smaller galaxy clusters. In Chapt. 6 we also derive the expected number counts of Radio Halos and compare them with available observations: we claim that » 100 Radio Halos in the Universe can be observed at 1.4 GHz with deep surveys, while more than 1000 Radio Halos are expected to be discovered in the next future by LOFAR at 150 MHz. This is the first (and so far unique) model expectation for the number counts of Radio Halos at lower frequency and allows to design future radio surveys. Based on the results of Chapt. 6, in Chapt.7 we present a work in progress on a “revision” of the occurrence of Radio Halos. We combine past results from the NVSS radio survey (z » 0.05 − 0.2) with our ongoing GMRT Radio Halos Pointed Observations of 50 X-ray luminous galaxy clusters (at z » 0.2−0.4) and discuss the possibility to test our model expectations with the number counts of Radio Halos at z » 0.05 − 0.4. The most relevant limitation in the calculations presented in Chapt. 5 and 6 is the assumption of an “averaged” size of Radio Halos independently of their radio luminosity and of the mass of the parent clusters. This assumption cannot be released in the context of the PS formalism used to describe the formation process of clusters, while a more detailed analysis of the physics of cluster mergers and of the injection process of turbulence in the ICM would require an approach based on numerical (possible MHD) simulations of a very large volume of the Universe which is however well beyond the aim of this PhD thesis. On the other hand, in Chapt.8 we report our discovery of novel correlations between the size (RH) of Radio Halos and their radio power and between RH and the cluster mass within the Radio Halo region, MH. In particular this last “geometrical” MH − RH correlation allows us to “observationally” overcome the limitation of the “average” size of Radio Halos. Thus in this Chapter, by making use of this “geometrical” correlation and of a simplified form of the re-acceleration model based on the results of Chapt. 5 and 6 we are able to discuss expected correlations between the synchrotron power and the thermal cluster quantities relative to the radio emitting region. This is a new powerful tool of investigation and we show that all the observed correlations (PR − RH, PR − MH, PR − T, PR − LX, . . . ) now become well understood in the context of the re-acceleration model. In addition, we find that observationally the size of Radio Halos scales non-linearly with the virial radius of the parent cluster, and this immediately means that the fraction of the cluster volume which is radio emitting increases with cluster mass and thus that the non-thermal component in clusters is not self-similar.

Percorsi di gender performance: fotografia tra arte e moda dagli anni Novanta ad oggi

My project explores and compares different forms of gender performance in contemporary art and visual culture according to a perspective centered on photography. Thanks to its attesting power this medium can work as a ready-made. In fact during the 20th century it played a key role in the cultural emancipation of the body which (using a Michel Foucault’s expression) has now become «the zero point of the world». Through performance the body proves to be a living material of expression and communication while photography ensures the recording of any ephemeral event that happens in time and space. My questioning approach considers the gender constructed imagery from the 1990s to the present in order to investigate how photography’s strong aura of realism promotes and allows fantasies of transformation. The contemporary fascination with gender (especially for art and fashion) represents a crucial issue in the global context of postmodernity and is manifested in a variety of visual media, from photography to video and film. Moreover the internet along with its digital transmission of images has deeply affected our world (from culture to everyday life) leading to a postmodern preference for performativity over the more traditional and linear forms of narrativity. As a consequence individual borders get redefined by the skin itself which (dissected through instant vision) turns into a ductile material of mutation and hybridation in the service of identity. My critical assumptions are taken from the most relevant changes occurred in philosophy during the last two decades as a result of the contributions by Jacques Lacan, Michel Foucault, Jacques Derrida, Gilles Deleuze who developed a cross-disciplinary and comparative approach to interpret the crisis of modernity. They have profoundly influenced feminist studies so that the category of gender has been reassessed in contrast with sex (as a biological connotation) and in relation to history, culture, society. The ideal starting point of my research is the year 1990. I chose it as the approximate historical moment when the intersection of race, class and gender were placed at the forefront of international artistic production concerned with identity, diversity and globalization. Such issues had been explored throughout the 1970s but it was only from the mid-1980s onward that they began to be articulated more consistently. Published in 1990, the book "Gender trouble: feminism and the subversion of identity" by Judith Butler marked an important breakthrough by linking gender to performance as well as investigating the intricate connections between theory and practice, embodiment and representation. It inspired subsequent research in a variety of disciplines, art history included. In the same year Teresa de Lauretis launched the definition of queer theory to challenge the academic perspective in gay and lesbian studies. In the meantime the rise of Third Wave Feminism in the US introduced a racially and sexually inclusive vision over the global situation in order to reflect on subjectivity, new technologies and popular culture in connection with gender representation. These conceptual tools have enabled prolific readings of contemporary cultural production whether fine arts or mass media. After discussing the appropriate framework of my project and taking into account the postmodern globalization of the visual, I have turned to photography to map gender representation both in art and in fashion. Therefore I have been creating an archive of images around specific topics. I decided to include fashion photography because in the 1990s this genre moved away from the paradigm of an idealized and classical beauty toward a new vernacular allied with lifestyles, art practices, pop and youth culture; as one might expect the dominant narrative modes in fashion photography are now mainly influenced by cinema and snapshot. These strategies originate story lines and interrupted narratives using models’ performance to convey a particular imagery where identity issues emerge as an essential part of fashion spectacle. Focusing on the intersections of gender identities with socially and culturally produced identities, my approach intends to underline how the fashion world has turned to current trends in art photography and in some case turned to the artists themselves. The growing fluidity of the categories that distinguish art from fashion photography represents a particularly fruitful moment of visual exchange. Varying over time the dialogue between these two fields has always been vital; nowadays it can be studied as a result of this close relationship between contemporary art world and consumer culture. Due to the saturation of postmodern imagery the feedback between art and fashion has become much more immediate and then increasingly significant for anyone who wants to investigate the construction of gender identity through performance. In addition to that a lot of magazines founded in the 1990s bridged the worlds of art and fashion because some of their designers and even editors were art-school graduates encouraging innovation. The inclusion of art within such magazines aimed at validating them as a form of art in themselves supporting a dynamic intersection for music, fashion, design and youth culture: an intersection that also contributed to create and spread different gender stereotypes. This general interest in fashion produced many exhibitions of and about fashion itself at major international venues such as the Victoria and Albert Museum in London, the Metropolitan Museum of Art and the Solomon R. Guggenheim Museum in New York. Since then this celebrated success of fashion has been regarded as a typical element of postmodern culture. Owing to that I have also based my analysis on some important exhibitions dealing with gender performance like "Féminin-Masculin" at the Centre Pompidou of Paris (1995), "Rrose is a Rrose is a Rrose. Gender performance in photography" at the Solomon R. Guggenheim Museum of New York (1997), "Global Feminisms" at the Brooklyn Museum (2007), "Female Trouble" at the Pinakothek der Moderne in München together with the workshops dedicated to "Performance: gender and identity" in June 2005 at the Tate Modern of London. Since 2003 in Italy we have had Gender Bender - an international festival held annually in Bologna - to explore the gender imagery stemming from contemporary culture. In few days this festival offers a series of events ranging from visual arts, performance, cinema, literature to conferences and music. Being aware that any method of research is neither race nor gender neutral I have traced these critical paths to question gender identity in a multicultural perspective taking account of the political implications too. In fact, if visibility may be equated with exposure, we can also read these images as points of intersection of visibility with social power. Since gender assignations rely so heavily on the visual, the postmodern dismantling of gender certainty through performance has wide-ranging effects that need to be analyzed. In some sense this practice can even contest the dominance of visual within postmodernism. My visual map in contemporary art and fashion photography includes artists like Nan Goldin, Cindy Sherman, Hellen van Meene, Rineke Dijkstra, Ed Templeton, Ryan McGinley, Anne Daems, Miwa Yanagi, Tracey Moffat, Catherine Opie, Tomoko Sawada, Vanessa Beecroft, Yasumasa Morimura, Collier Schorr among others.

Il critico teatrale come operatore di scrittura scenica. La critica teatrale italiana tra pratica organizzativa e utilizzo dei nuovi media nel Nuovo Teatro e in alcune esperienze dal 2003 ad oggi

La crisi del “teatro come servizio pubblico” degli Stabili, Piccolo Teatro in testa, si manifesta allo stadio di insoddisfazione interna già alla fine degli anni Cinquanta. Se dal punto di vista della pratica scenica, la prima faglia di rottura è pressoché unanimemente ricondotta alla comparsa delle primissime messe in scena –discusse, irritanti e provocatorie- di Carmelo Bene e Quartucci (1959-60) più difficile è individuare il corrispettivo di un critico-intellettuale apportatore di una altrettanto deflagrante rottura. I nomi di Arbasino e di Flaiano sono, in questo caso, i primi che vengono alla mente, ma, seppure portatori di una critica sensibile al “teatro ufficiale”, così come viene ribattezzato dopo il Convegno di Ivrea (1967) il modello attuato dagli Stabili, essi non possono, a ben vedere, essere considerati i veri promotori di una modalità differente di fare critica che, a partire da quel Convegno, si accompagnerà stabilmente alla ricerca scenica del Nuovo Teatro. Ma in cosa consiste, allora, questa nuova “operatività” critica? Si tratta principalmente di una modalità capace di operare alle soglie della scrittura, abbracciando una progressiva, ma costante fuoriuscita dalla redazione di cronache teatrali, per ripensare radicalmente la propria attività in nuovi spazi operativi quali le riviste e l’editoria di settore, un rapporto sempre più stretto con i mass-media quali radio e televisione e la pratica organizzativa di momenti spettacolari e teorici al contempo -festival, convegni, rassegne e premi- per una forma di partecipazione poi identificata come “sporcarsi le mani”. La seconda parte della tesi è una raccolta documentaria sull’oggi. A partire dal Manifesto dei Critici Impuri redatto nel 2003 a Prato da un gruppo di critici dell'ultima generazione, la tesi utilizza quella dichiarazione come punto di partenza per creare un piccolo archivio sull’oggi raccogliendo le elaborazioni di alcune delle esperienze più significative di questi dieci anni. Ricca appendice di materiali.

Studi sull'immaginario musicale in Euripide

La dissertazione è suddivisa in due capitoli più tre appendici. Nel I capitolo, Musica e dolore, si indagano i casi di metamusicalità in riferimento al dolore, che si intensificano in Euripide: si nota lo sviluppo di una riflessione sul ruolo della mousike rispetto al dolore, espressa attraverso un lessico medico e musicale. Si dimostra che in Euripide si pone il problema di quale scopo abbia la musica, se sia utile, e in quale forma lo sia. Nella prima produzione si teorizza una mousa del lamento come dolce o terapeutica per chi soffre. Molti personaggi, però, mostrano sfiducia nel potere curativo del lamento. Nell’ultima produzione si intensificano gli interrogativi sulla performance del canto, che si connotano come casi metamusicali e metateatrali. Nell’Elena, nell’Ipsipile e nelle Baccanti, E. sembra proporre una terapia ‘omeopatica’ del dolore attraverso la musica orgiastico-dionisiaca. Nel II capitolo, Natura e musica, si sceglie l’Ifigenia Taurica come esempio di mimetismo orchestico-musicale fondato – oltre che su casi di autoreferenzialità – su un immaginario naturale che, ‘facendo musica’, contribuisce all’espressività della choreia e della musica in scena. Si ipotizza inoltre un accompagnamento musicale mimetico rispetto ai suoni della natura e movimenti di danza lineari accanto a formazioni circolari, che sembrano richiamare la ‘doppia natura’ del ditirambo. L’Appendice I, Gli aggettivi poetici ξουθός e ξουθόπτερος: il loro significato e la loro potenzialità allusiva, affronta un caso particolare e problematico di ‘mimetismo lessicale’, innescato dal termine ξουθός e dal composto euripideo ξουθόπτερος. Si dimostra che l’aggettivo indica originariamente un movimento vibratorio, ma sviluppa anche un senso sonoro, ed è quindi un termine evocativo rispetto alla performance. Nell’Appendice II, Il lessico musicale in Euripide, è raccolto il lessico euripideo coreutico-musicale. Nell’Appendice III, La mousike nei drammi euripidei, sono raccolti i riferimenti alla mousike in ogni dramma.

Il repertorio italiano del Ms Gr. Rés. Vm7 676 della Biblioteca Nazionale di Parigi

La tesi esamina il codice musicale Gr. Rés Vm7 676 della Biblioteca Nazionale di Parigi, che rappresenta una fonte di grande interesse per lo studio della musica vocale italiana tra Quattro e Cinquecento. Compilato nel 1502, il codice è stato oggetto di analisi da parte di vari studiosi, che ne hanno preso in esame singoli brani o intere sezioni, allo scopo di attestare procedimenti compositivi particolari (Torrefranca) o caratteri stilistici locali, in particolare relativi alla frottola mantovana e ferrarese (Prizer). Un’accurata ricognizione sul repertorio è stata effettuata da Nanie Bridgman in un saggio degli anni Cinquanta del secolo scorso, ma non è mai stato realizzato uno studio organico sul manoscritto. Pertanto la ricerca si è proposta di riconsiderare l’intero repertorio italiano tramandato dal codice, per proporre un plausibile inquadramento stilistico nella cultura della poesia per musica coeva. La trascrizione dei testi e delle musiche, supportata dal confronto con le fonti manoscritte e a stampa, letterarie e musicali, ha consentito di formulare alcune ipotesi in merito alla circolazione del repertorio tramandato e all’ambiente di produzione del documento. L’inconsueta varietà di forme musicali riscontrate nel codice consente inoltre di assumere questo manoscritto come una delle principali fonti della tradizione musicale che precede immediatamente la ‘sistemazione’ del repertorio frottolistico effettuata da Ottaviano Petrucci, a partire dal 1504, con la pubblicazione dei suoi undici libri di frottole (1501-1514).

Le rappresentazioni sociali della musica degli insegnanti di scuola dell'infanzia. Documenti orientativi e indagini empiriche a confronto tra Italia e Venezuela

Questo lavoro si occupa di studiare l’effetto delle rappresentazioni sociali della musica degli studenti universitari che diventeranno insegnanti di scuola dell’infanzia e in particolare i cambiamenti che intervengono durante il periodo di formazione universitaria sia italiana sia venezuelana. Obiettivo fondamentale è quindi realizzare un’analisi comparativa sulle seguenti tematiche: bambino musicale, competenze dell’insegnante e finalità dell’educazione musicale. Questo lavoro si è inserito all’interno del progetto “Il sapere musicale come rappresentazione sociale” (Addessi-Carugati 2010). L’ipotesi guida è che le concezioni implicite della musica funzionino come rappresentazioni sociali che influenzano le pratiche dell’insegnamento e dell’educazione musicale. Il primo capitolo, affronta i temi dei bambini, degli insegnanti e dell’educazione musicale nella scuola dell’infanzia in Italia e Venezuela. Nel secondo vengono presentati gli studi sui saperi musicali; la teoria delle rappresentazioni sociali (Moscovici 1981) e il progetto pilota realizzato presso l’Università di Bologna “Il sapere musicale come Rappresentazione Sociale”. Il capitolo successivo presenta l'analisi e l'interpretazione dell’indagine empirica effettuata su un gruppo di studenti dei corsi di formazione per insegnanti dell’Università di Mérida (Venezuela). Nel quarto capitolo si sviluppano riflessioni e discussioni riguardo i risultati dello studio comparativo; i piani e programmi di studio universitari e il profilo professionale musicale dell’insegnante. Le conclusioni finali illustrano come l’ipotesi iniziale sia effettivamente confermata: dall’analisi e interpretazione dei dati sembra che le concezioni implicite sui saperi musicali possedute dagli studenti influiscano sulla loro pratica professionale in qualità di futuri insegnanti. Si è anche osservato che le differenze incontrate sembrano essere dovute ai diversi tipi di variabili del contesto dove si trova l’insegnante di educazione musicale; e soprattutto ai significati espressi dai programmi di studi, dai contenuti didattici diversi, dai contesti sociali e culturali e dal curriculum universitario.

Luigi Nono: spazio e composizione

Architettura e musica. Spazio e tempo. Suono. Esperienza. Queste le parole chiave da cui ha preso avvio la mia ricerca. Tutto è iniziato dall’intuizione dell’esistenza di un legame tra due discipline cui ho dedicato molto tempo e studio, completando due percorsi accademici paralleli, la Facoltà di architettura e il Conservatorio. Dopo un lavoro d’individuazione e analisi degli infiniti spunti di riflessione che il tema offriva, ho focalizzato l’attenzione su uno degli esempi più emblematici di collaborazione tra un architetto e un musicista realizzatasi nel Novecento: Prometeo, tragedia dell’ascolto (1984), composta da Luigi Nono con la collaborazione di Massimo Cacciari e Renzo Piano. Attraverso lo studio di Prometeo ho potuto affrontare la trattazione di molte delle possibili declinazioni del rapporto interdisciplinare tra musica e architettura. La ricerca si è svolta principalmente sullo studio dei materiali conservati presso l’Archivio Luigi Nono e l’archivio della Fondazione Renzo Piano. La tesi è organizzata in tre parti: una prima parte in cui si affronta il tema del ruolo dello spazio nelle opere di Nono precedenti a Prometeo, facendo emergere l’importanza dell’ambiente culturale e sonoro veneziano; una seconda parte in cui si approfondisce il processo compositivo che ha portato alle rappresentazioni di Prometeo a Venezia, Milano e a Parigi; una terza parte in cui si prende in considerazione quanto avvenuto dopo Prometeo e si riflette sui contributi che questa esperienza può portare alla progettazione di spazi per la musica, analizzando diversi allestimenti dell’opera senza arca e prendendo in considerazione i progetti dell’auditorium dell’International Art Village di Akiyoshidai e della sala della nuova Philharmonie di Parigi. Lo studio dell’esperienza di Prometeo ha lo scopo di stimolare la curiosità verso la ricerca e la sperimentazione di quegli infiniti possibili della composizione architettonica e musicale di cui parla Nono.

Target Tracking in UWB Multistatic Radars

Detection, localization and tracking of non-collaborative objects moving inside an area is of great interest to many surveillance applications. An ultra- wideband (UWB) multistatic radar is considered as a good infrastructure for such anti-intruder systems, due to the high range resolution provided by the UWB impulse-radio and the spatial diversity achieved with a multistatic configuration. Detection of targets, which are typically human beings, is a challenging task due to reflections from unwanted objects in the area, shadowing, antenna cross-talks, low transmit power, and the blind zones arised from intrinsic peculiarities of UWB multistatic radars. Hence, we propose more effective detection, localization, as well as clutter removal techniques for these systems. However, the majority of the thesis effort is devoted to the tracking phase, which is an essential part for improving the localization accuracy, predicting the target position and filling out the missed detections. Since UWB radars are not linear Gaussian systems, the widely used tracking filters, such as the Kalman filter, are not expected to provide a satisfactory performance. Thus, we propose the Bayesian filter as an appropriate candidate for UWB radars. In particular, we develop tracking algorithms based on particle filtering, which is the most common approximation of Bayesian filtering, for both single and multiple target scenarios. Also, we propose some effective detection and tracking algorithms based on image processing tools. We evaluate the performance of our proposed approaches by numerical simulations. Moreover, we provide experimental results by channel measurements for tracking a person walking in an indoor area, with the presence of a significant clutter. We discuss the existing practical issues and address them by proposing more robust algorithms.

Keplero e la musica. Il Libro III dell'Harmonice mundi (Linz, 1619): traduzione e Introduzione

Questo lavoro si concentra su un particolare aspetto della sfaccettata ricerca scientifica di Johannes Kepler (1571-1630), ossia quello teorico-musicale. I pensieri dell’astronomo tedesco riguardanti tale campo sono concentrati – oltre che in alcuni capitoli del Mysterium cosmographicum (1596) ed in alcune sue lettere – nel Libro III dell’Harmonices mundi libri quinque (1619), che, per la sua posizione mediana all’interno dell’opera, tra i primi due libri geometrici e gli ultimi due astronomici, e per la sua funzione di raccordo tra la «speculazione astratta» della geometria e la concretizzazione degli archetipi geometrici nel mondo fisico, assume la struttura di un vero e proprio trattato musicale sul modello di quelli rinascimentali, nel quale la «musica speculativa», dedicata alla teoria delle consonanze e alla loro deduzione geometrica precede la «musica activa», dedicata alla pratica del canto dell’uomo nelle sue differenze, generi e modi. La tesi contiene la traduzione italiana, con testo latino a fronte, del Libro III dell’Harmonice, e un’ampia introduzione che percorre le tappe fondamentali del percorso biografico e scientifico che hanno portato alla concezione di quest’opera – soffermandosi in particolare sulla formazione musicale ricevuta da Keplero, sulle pagine di argomento musicale del Mysterium e delle lettere, e sulle riflessioni filosofico-armoniche sviluppate negli anni di ricerca – e offre gli elementi fondamentali per poter comprendere l’Harmonice mundi in generale e il Libro III in particolare. A ciò si aggiunge, in Appendice, la traduzione, anch’essa con testo latino a fronte, della Sectio V, dedicata alla musica, del Liber IX dell’Almagestum novum (1651) di Giovanni Battista Riccioli (1598-1671), interessante sia dal punto di vista della recezione delle teorie di Keplero che dal punto di vista della storia delle idee musicali.

Non-thermal emission in High Frequency Peaked blazars towards the Square Kilometer Array era

In this thesis work we will explore and discuss the properties of the gamma-ray sources included in the first Fermi-LAT catalog of sources above 10 GeV (1FHL), by considering both blazars and the non negligible fraction of still unassociated gamma-ray sources (UGS, 13%). We perform a statistical analysis of a complete sample of hard gamma-ray sources, included in the 1FHL catalog, mostly composed of HSP blazars, and we present new VLBI observations of the faintest members of the sample. The new VLBI data, complemented by an extensive search of the archives for brighter sources, are essential to gather a sample as large as possible for the assessment of the significance of the correlation between radio and very high energy (E>100 GeV) emission bands. After the characterization of the statistical properties of HSP blazars and UGS, we use a complementary approach, by focusing on an intensive multi-frequency observing VLBI and gamma-ray campaign carried out for one of the most remarkable and closest HSP blazar Markarian 421.