On the multiplicity of Laplacian eigenvalues and Fiedler partitions

In this paper we study two classes of graphs, the (m,k)-stars and l-dependent graphs, investigating the relation between spectrum characteristics and graph structure: conditions on the topology and edge weights are given in order to get values and multiplicities of Laplacian matrix eigenvalues. We prove that a vertex set reduction on graphs with (m,k)-star subgraphs is feasible, keeping the same eigenvalues with reduced multiplicity. Moreover, some useful eigenvectors properties are derived up to a product with a suitable matrix. Finally, we relate these results with Fiedler spectral partitioning of the graph. The physical relevance of the results is shortly discussed

Errors, Correlations and Fidelity for noisy Hamilton flows. Theory and numerical examples

We analyse the asymptotic growth of the error for Hamiltonian flows due to small random perturbations. We compare the forward error with the reversibility error, showing their equivalence for linear flows on a compact phase space. The forward error, given by the root mean square deviation $\sigma(t)$ of the noisy flow, grows according to a power law if the system is integrable and according to an exponential law if it is chaotic. The autocorrelation and the fidelity, defined as the correlation of the perturbed flow with respect to the unperturbed one, exhibit an exponential decay as $\exp\left(-\sigma^2(t)\right)$. Some numerical examples such as the anharmonic oscillator and the H\'enon Heiles model confirm these results. We finally consider the effect of the observational noise on an integrable system, and show that the decay of correlations can only be observed after a sequence of measurements and that the multiplicative noise is more effective if the delay between two measurements is large.Comment: 22 pages, 3 figure

Dalla Pangea ...

Il Mediterraneo non è sempre stato come lo vediamo oggi, ma è il risultato di una complessa evoluzione geodinamica. La sua storia geologica inizia circa 250 milioni di anni fa (Ma) quando i grandi movimenti della crosta terrestre iniziano a frammentare la Pangea e a formare la Tetide, un mare interposto tra due “supercontinenti”, Laurasia e Gondwana

Protons Acceleration by CO2 Laser Pulses and Perspectives for Medical Applications

In the present note we shall review the basic mechanisms for laser acceleration to present the related scaling laws and compare the results one expects from small (1 \u3bc) and large (10 \u3bc) wavelength pulses. Systematic 2D and 3D simulations were performed with the high order PICcodeALaDyn [Benedetti et al.(2008)] developedbytheuniversityofBolognatoprovide quantitative results in addition to the qualitative results of scaling laws. We shall also discuss the transport of a protons beam through an optical system. The paper consists of six sections: after this introduction, in section 2 we recall the basic features and parameters of the laser beam, in section 3 the TNSA regime is reviewed, in section 4 the RPA regime is presented, in section 5 the acceleration on under-critical target is discussed, in section 6 we discuss the transport of the optically accelerated proton bunch, in section 7 we analyze the perspectives for therapy

Il deposito legale regionale in Italia: stato dell’arte e risultati di una recente indagine

The article sets out the results of the survey conducted between October and November 2019 by the Commissione nazionale biblioteche e servizi nazionali of the AIB on Regional Legal Deposit, fifteen years after the last field research on the same subject. The Regional Legal Deposit was established by Law 106/2004 and regulated by Presidential Decree 252/2006 and two ministerial decrees of 2007 and 2009. This set of rules provides that each publisher should send several copies of its publications to certain libraries in the Region where the publishing houses are based to create a regional archive of the Italian editorial production. Regional Legal Deposit is one of the most innovative, albeit most critical and lesser-known, aspects of legal deposit regulation. In the first phase of the investigation, it was decided to make an accurate analysis of the information released by the libraries themselves, which made it possible to photograph the reality of the regional depository libraries in Italy, partially changed since 2009. The second phase of the survey consisted of an online questionnaire addressed to depository libraries, divided into nine questions – each of which included three closed responses and the opportunity to leave a comment. The survey, which obtained a good degree of participation (62%), showed a somewhat similar situation to the past, highlighting the problems of insufficient storage space, insufficient staff, lack of resources and excessive dependence on local policies. However, some of the answers to the questionnaire are encouraging: publications are sent with a certain regularity, the Regional Legal Deposit is perceived as an obligation that has also positive aspects and checks are carried out on its fulfillment. In addition emerges the importance of setting up a unified publisher database, which could facilitate the management of the Legal Deposit and provide a starting point for future synergies.L’articolo espone i risultati dell’indagine condotta dalla Commissione nazionale biblioteche e servizi nazionali dell’AIB sul deposito legale regionale fra ottobre e novembre 2019, a quindici anni dall’ultima ricerca sul campo che aveva per oggetto la stessa tematica. Il deposito legale regionale, istituito con la l. 106/2004 e regolato dal d.p.r. 252/2006 e da due decreti ministeriali del 2007 e del 2009, prevede che ogni editore invii un certo numero di copie delle proprie pubblicazioni a determinate biblioteche della Regione in cui le case editrici hanno sede, al fine di creare un archivio regionale della produzione editoriale italiana. Esso costituisce uno degli aspetti più innovativi ma anche più critici e meno conosciuti nell’ambito della normativa sul deposito legale. Nella prima fase dell’indagine si è deciso di effettuare un’analisi delle informazioni rilasciate dalle stesse biblioteche che consentisse di fotografare la realtà delle biblioteche depositarie regionali sul territorio italiano, parzialmente mutata rispetto al 2009. La seconda fase dell’indagine è consistita nella somministrazione di un questionario online rivolto alle biblioteche depositarie, articolato in nove domande – ciascuna delle quali prevedeva tre risposte chiuse e la possibilità di commentare. L’indagine, che ha ottenuto un confortante dato di partecipazione (62%), ha mostrato una situazione non troppo diversa dal passato, evidenziando soprattutto i problemi della mancanza di spazi, della carenza di personale, di risorse e la dipendenza dalle politiche locali. Alcune risposte al questionario sono però incoraggianti: le pubblicazioni arrivano con una certa regolarità, il deposito legale regionale è percepito come un obbligo che comporta anche aspetti positivi e vengono operate verifiche sul suo adempimento. Emerge l’importanza di approntare un database unificato degli editori, che potrebbe agevolare la gestione del deposito legale e costituire un punto di partenza per sinergie future

Context-Aware Sensing and Implicit Ground Truth Collection: Building a Foundation for Event Triggered Surveys on Autonomous Shuttles: Artikel

The LINC project aims to study interactions between passengers and autonomous vehicles in natural settings at the campus of Technical University of Denmark. To leverage the potential of IoT components in smartphone-based surveying, a system to identify specific spatial, temporal and occupancy contexts relevant for passengers’ experience was proposed as a central data collection strategy in the LINC project. Based on predefined contextual triggers specific questionnaires can be distributed to affected passengers. This work focuses on the data-based discrimination between two fundamental contexts for LINC passengers: be-in and be-out (BIBO) of the vehicle. We present empirical evidence that Bluetooth-low-energy beacons (BLE) have the potential for BIBO independent classification. We compare BLE with other smartphone onboard sensors, such as the global positioning system (GPS) and the accelerometer through: (i) random-forest (RF); (ii) multi-layer perceptron (MLP); and (iii) smartphone native off-the-shelve classifiers. We also perform a sensitivity analysis regarding the impact that faulty BIBO ground-truth has on the performance of the supervised classifiers (i) and (ii). Results show that BLE and GPS could allow reciprocal validation for BIBO passengers’ status. This potential might lift passengers from providing any further validation. We describe the smartphone-sensing platform deployed to gather the dataset used in this work, which involves passengers and autonomous vehicles in a realistic setting

Bifurcations of beam-beam like maps

The bifurcations of a class of mappings including the beam-beam map are examined. These maps are asymptotically linear at infinity where they exhibit invariant curves and elliptic periodic points. The dynamical behaviour is radically different with respect to the Henon-like polynomial maps whose stability boundary (dynamic aperture) is at a finite distance. Rather than the period-doubling bifurcations exhibited by the Henon-like maps, we observe a systematic appearance of tangent bifurcations and in phase space one observes the disappearance of chains of islands born from the origin and coming from infinity. This behaviour has relevant consequences on the transport process

Il deposito legale regionale in Italia: stato dell’arte e risultati di una recente indagine

The article sets out the results of the survey conducted between October and November 2019 by the Commissione nazionale biblioteche e servizi nazionali of the AIB on Regional Legal Deposit, fifteen years after the last field research on the same subject. The Regional Legal Deposit was established by Law 106/2004 and regulated by Presidential Decree 252/2006 and two ministerial decrees of 2007 and 2009. This set of rules provides that each publisher should send several copies of its publications to certain libraries in the Region where the publishing houses are based to create a regional archive of the Italian editorial production. Regional Legal Deposit is one of the most innovative, albeit most critical and lesser-known, aspects of legal deposit regulation. In the first phase of the investigation, it was decided to make an accurate analysis of the information released by the libraries themselves, which made it possible to photograph the reality of the regional depository libraries in Italy, partially changed since 2009. The second phase of the survey consisted of an online questionnaire addressed to depository libraries, divided into nine questions – each of which included three closed responses and the opportunity to leave a comment. The survey, which obtained a good degree of participation (62%), showed a somewhat similar situation to the past, highlighting the problems of insufficient storage space, insufficient staff, lack of resources and excessive dependence on local policies. However, some of the answers to the questionnaire are encouraging: publications are sent with a certain regularity, the Regional Legal Deposit is perceived as an obligation that has also positive aspects and checks are carried out on its fulfillment. In addition emerges the importance of setting up a unified publisher database, which could facilitate the management of the Legal Deposit and provide a starting point for future synergies