Deu anys de cor a la UdG

El Cor de la UdG fa 10 anys. La formació coral ha assolit una dolça maduresa que no és obstacle per ambicionar nous reptes. El seu punt fort és haver aconseguit un alt grau de cohesió, un sentiment de pertinença que conviu amb la renovació natural del grup de cantants

Relacions entre la identitat catalana i la percepció de vitalitat etnolingüística en una mostra d’estudiants universitaris

This article analyses, on the one hand, the perception of ethno-linguistic vitality in a sample of university students in the province of Girona, and, on the other, links this perceived vitality to the feeling of identity in the group to which they belong. 112 Catalan-speaking students who described themselves as Catalan (Catalan identity) responded to the questionnaire on subjective vitality, in terms of adaptation to Catalan. This instrument assesses the beliefs about one’s own group’s and its language’s vitality (in this case Catalan) and that of the exocentric group and language (in this case Spanish). The results show that the students see their language (Catalan) as having greater status and institutional support than Spanish, but a lower demographic impact (birth rate, immigration, mixed marriages, emigration). Identity is also positively correlated with the perception of ethno-linguistic perception. These results are discussed in relation to the role of vitality in the choice of the language for education (Catalan versus Spanish) and day-to-day communication, and the level at which language policy is defined in order to promote communication in Catalan in the fields of business, politics, education and the media

Enhanced convolution approach for CAC in ATM networks, an analytical study and implementation

The characteristics of service independence and flexibility of ATM networks make the control problems of such networks very critical. One of the main challenges in ATM networks is to design traffic control mechanisms that enable both economically efficient use of the network resources and desired quality of service to higher layer applications. Window flow control mechanisms of traditional packet switched networks are not well suited to real time services, at the speeds envisaged for the future networks. In this work, the utilisation of the Probability of Congestion (PC) as a bandwidth decision parameter is presented. The validity of PC utilisation is compared with QOS parameters in buffer-less environments when only the cell loss ratio (CLR) parameter is relevant. The convolution algorithm is a good solution for CAC in ATM networks with small buffers. If the source characteristics are known, the actual CLR can be very well estimated. Furthermore, this estimation is always conservative, allowing the retention of the network performance guarantees. Several experiments have been carried out and investigated to explain the deviation between the proposed method and the simulation. Time parameters for burst length and different buffer sizes have been considered. Experiments to confine the limits of the burst length with respect to the buffer size conclude that a minimum buffer size is necessary to achieve adequate cell contention. Note that propagation delay is a no dismiss limit for long distance and interactive communications, then small buffer must be used in order to minimise delay. Under previous premises, the convolution approach is the most accurate method used in bandwidth allocation. This method gives enough accuracy in both homogeneous and heterogeneous networks. But, the convolution approach has a considerable computation cost and a high number of accumulated calculations. To overcome this drawbacks, a new method of evaluation is analysed: the Enhanced Convolution Approach (ECA). In ECA, traffic is grouped in classes of identical parameters. By using the multinomial distribution function instead of the formula-based convolution, a partial state corresponding to each class of traffic is obtained. Finally, the global state probabilities are evaluated by multi-convolution of the partial results. This method avoids accumulated calculations and saves storage requirements, specially in complex scenarios. Sorting is the dominant factor for the formula-based convolution, whereas cost evaluation is the dominant factor for the enhanced convolution. A set of cut-off mechanisms are introduced to reduce the complexity of the ECA evaluation. The ECA also computes the CLR for each j-class of traffic (CLRj), an expression for the CLRj evaluation is also presented. We can conclude that by combining the ECA method with cut-off mechanisms, utilisation of ECA in real-time CAC environments as a single level scheme is always possible.