1,721,020 research outputs found
Musica e Figura
No full text"Musica e Figura" è una rivista promossa dalla Fondazione Ugo e Olga Levi onlus di Venezia e dal Dipartimento di Storia delle arti visive e della musica dell'Università di Padova. Essa trae origine dall'intenzione di presentare scritti di storia dell'arte e di storia della musica, prodotti anzitutto da studiosi accomunati dall'esperienza del Dipartimento di Storia delle arti visive e della musica e della Scuola di Dottorato in storia e critica dei beni artistici, musicali e dello spettacolo dell'Università di Padova. La relazione tra i due campi si basa sulla ricognizione di ambiti di committenza e condizioni sociali favorevoli; sulla ricerca dei modelli storiografici utilizzati in varie epoche per valorizzare le opere passate e presenti, in un ampio disegno nazionale e internazionale; sui suggerimenti che possono derivare dalle analisi linguistiche messe in opera nei due settori, il cui confronto ha comunque offerto nel tempo importanti modelli di riflessione metodica
Generalized Parallel Delta Networks: a New Class of Rearrangeable Interconnection Networks
No full textThis paper deals with the definition of a class of NxN multistage interconnection networks called Generalized Parallel Delta Networks (GPDNs). This class includes the already known Replicated Delta Networks (RDNs) and Parallel Delta
Networks (PDNs). For the GPDNs the rearrangeability condition is given and a routing algorithm for the establishment of any set of connection requests is presented. The proposed algorithm operates in case of GPDNs composed of 2Qx2Q swtching elements and it is able to set-up any permutation with a time complexity equal to O(Nlog2N).
As far as the implementation of rearrangeable topologies is concerned, the fields of applicability of RDNs, PDNs and other GPDNs have been investigated. In particular, it has been proved that, if large networks (N)256) have to be implemented, GPDNs structures requires a lower number of switching elements with respect to RDNs and PDNs. This features can be obtained without any impairment on the complexity of the routing algorithm
On non-blocking properties of Parallel Delta Networks
No full textThis paper deals with the definition of a class of NxN interconnection networks called Parallel Delta Network (PDN). For this class of networks the non-blocking conditions are given. In particular, by means of the graph colouring technique, it has been proved that the minimum number of Delta subnetworks (L) necessary to provide the non-blocking property is L=nfS/21-1 where n is the size of the basic switching element and S the number of stages required by an NxN Delta network. A routing algorithm for the establishment of any permutation has been defined.
It operates for any value of n and shows a polynomial time
complexity equal to O(N3/2). Moreover, in case of the setup
of a single connection request, this algorithm assures a
time complexity equal to O(VN). This property makes it
well suitable to an asynchronous telecommunication
environment
Distributed CBO call set-up in a circuit emulation ATM switch
No full textThis paper deals with a fully distributed routing control scheme, called flooding technique, to be applied to an ATM switch architecture for the set-up of CBO calls. The main advantage of this technique with respect to a centralized solution consists in a sensitive improvement of the system performance, in particular as far as the fault-tolerance and the flexibility are concerned. Two service scenarios are considered: in the first one the CBO services are characterized by a burstiness equal to one, in the second one they have a burstiness greater than one. The implementation alternatives of the flooding technique relevant to both the scenarios are presented and their main characteristics arecompared. In the paper, the ATM switch architecture and its mode of operation are also described. In particular, the different strategies for the handling of CBO and non-isochronous classes of traffic are presented and some properties on the topology of the switching fabric are given
Evolution of the Generalized Parallel Delta Networks towards a photonic switching environment
No full textThis paper deals with the non-blocking properties of the Generalized Parallel Delta Networks and their application to the photonic switching environment. The peculiar characteristics of GPDNs well suit the constraints arising from this new application area In particular, these characteristics consist in a low number of stages and a high fault tolerance due to the stacking of identical Delta networks. Moreover, it is here demonstrated that the crosstalk due to the switch crossover can be completely avoided by means of a proper dimensioning of the network parameters. A new classification of the non-blocking properties is proposed. In particular, a new non-blocking condition, named as strong, has been defined. It establishes that two paths are not in conflict if they do not share any switching element. The strong non-blocking condition has been considered together with the traditional one. This second condition is normally applied in the electronic environment; as it is based on the unshareability of the interstage links, here, it is named as weak. The conditions which have to be satisfied so that a Generalized Parallel Delta Network can be weakly and/or strongly non-blocking have been found and demonstrated
Efficiency and fairness issues in multihop networks supporting a guaranteed bandwidth transport service
No full textThis paper deals with the feasibility of a Guaranteed Bandwidth Transport Service (GBTS) on Shuffle Multihop Networks (SMHNs); moreover. a simple Resource Allocation Protocol. allowing a high flexibility in bandwidth allocation, is proposed. A performance study is carried out to verify the response of the SMHNs to GB traffic. In particular, the path blocking probability is evaluated by means of an analytical model in the cases of balanced and unbalanced loads. A comparison with the performance of similar LAN/MAN structures, i.e. simple ring and ring with spatial reuse, is carried out. Finally, a methodology to manage the resources in order to make the grade of service independent of the physical location of the network nodes is proposed and its impact on the network performance is evaluated. Moreover, some considerations about its actual implementation are presented
Throughput analysis of multihop shufflenets in a hot spot traffic scenario: impact of routing strategies
No full textThis paper deals with the analysis of the throughput performance of Shuffle Multihop Networks under general traffic configurations and aims at investigating the impact of different classes of routing schemes. A hot-spot traffic scenario was considered, modeling the presence of a centralized network resource to which a quota of the internal traffic is directed or originated from. The analysis was carried out by varying the traffic unbalance degree, from a uniform traffic distribution to a completely unbalanced one (all the traffic is concentrated in the hot spot node). As for the routing algorithms, both minimum path length (fixed or adaptive) and unconstrained path length schemes are studied. Simple analytical expressions of the actual throughput limits were obtained for each class of routing algorithms. By comparing the upper bounds with simulation results, it is shown that there exists an increase in the tightness of the upper bound which can be directly correlated to an increase in the network size. The results obtained show that the throughput performance deteriorates for increasing unbalance of the network load. This worsening can be partially relieved by employing adaptive routing algorithms. These algorithms provide remarkable throughput improvements with respect to fixed routing schemes, but only in the case of moderate hot spot traffic quota. Moreover, results show that unconstrained path length routing schemes lead to the best performance provided that the maximum path length be bounded
Presentazione
No full textLa breve introduzione spiega le ragioni e gli obiettivi che hanno portato alla pubblicazione dell'annuario interdisciplinare "Musica e Figura", nato all’interno del Dipartimento di storia delle arti visive e della musica e della Scuola di Dottorato in storia e critica dei beni artistici, musicali e dello spettacolo dell'Università di Padova, in collaborazione con la Fondazione Ugo e Olga Levi di Venezia. La rivista è stata pensata per i giovani, per offrire una sede amica agli studi da loro intrapresi negli anni di vita universitaria e post-universitaria, nell’ambito della struttura nella quale si sono formati. Essa, però, non è né intende essere un organo ufficiale, ma vuole garantire piena libertà alla collaborazione nel rispetto delle linee programmatiche, senza alcuna chiusura verso contributi che vengano dal di fuori per contatti e collaborazioni variamente intrecciati. I vari progetti sulle relazioni tra arti visive e musica che il Dipartimento di Padova sostiene costituiscono il nucleo, metodologico e tematico, che giustifica l’unità di «musica e figura», termini che vanno intesi come allusione all’attività artistica e all’invenzione musicale nel loro gesto più originale rispetto ai condizionamenti posti dalla realtà
A FULLY DISTRIBUTED ROUTING CONTROL SCHEME IN AN ATM SWITCH
No full textThis paper deals with a fully distributed routing control scheme, called flooding technique, to be applied to an ATM switch architecture for the set-up of CBO calls. The aim of the flooding technique is to find, in a completely distributed fashion, an available path, between the source and destination line units, through the switching fabric in order to route the cells belonging to a CBO call. The main advantages of this technique with respect to a centralized solution consist in a sensitive improvement of both the system performance and its fault-tolerance and a greater flexibility in case of the system grow. In the paper, the switch architecture and its mode of operation are also described. In particular, the different strategies for the handling of CBO and non-isochronous classes of traffic are presented and some properties on the topology of the switching fabric are given
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