1,720,974 research outputs found
Performance of the Vickrey auction for digital goods under various bid distributions
Get PDFThe generalized Vickrey auction is analysed as a mechanism for setting prices of digital goods. A selection of models of the bidders' behaviour (embodied by the probability distribution of their bids' values) are employed to derive the optimal auctioneer's choice as to the number of items to sell. The satisfaction levels of both the auctioneer and the bidders are taken into account through the evaluation of the expected revenues, the percentage of winning bidders and their aggregated utilities under each of the probabilistic scenarios considered. (C) 2007 Elsevier B.V. All rights reserved
Hypertextual Pedagogy and the genre of Web-mediated Citizenship Lessons
No full textThis paper sets out to analyse the genre of the lesson plan as it has evolved from its traditional paper version into an online multimodal resource and to examine which conventional and changing features characterize Internet-based lessons. In particular, our study is focused on citizenship lessons because of the current interest in civic engagement (Mintzber 1996; Dunkin et al. 1998) and of the mainstream view fostered by the media that ordinary citizens have a role to play besides leading politicians and that they can and must indeed take part in global governance
A normal copula model for the economic risk analysis of correlated failures in communications networks
No full textThe reliability of a communications network is often evaluated without taking into account the economic consequence of failures. Here a new approach is proposed to assess the economic consequences of failures as a figure of merit of reliable networks. For this purpose a partition of the network operator’s market into service basins is proposed, which includes the presence of correlation between the subsystems needed to serve different service basins as well as within the same service basin. A simulation algorithm, based on the Cross-Entropy method, is fully described to evaluate the probability that the economic loss exceeds a given threshold. An application of the method to a simple scenario is finally reported
Option pricing in a privacy-aware market
No full textIn a privacy-aware market a producer may satisfy the demand by end customers either by producing itself the items or by placing the items provided by privacy-aware suppliers at a reduced price. Price-aware suppliers provide a noisy information about their level of stock. Through an option contract the producer may protect itself against the risk of buying also the excess items delivered by privacy- aware suppliers. We provide a formula for the option price, which is found to be somewhat larger than the cost of the declared excess items
Cross-entropy-based adaptive optimization of simulation parameters for Markovian-driven service systems
No full textMarkov fluid models represent a general description of the process of service request arrivals to service systems. The solution of performance analysis problems incorporating them often calls for a simulation approach, for which a reference methodology is Importance Sampling. However, in this case the appropriate choice of the biasing conditions is a problem in itself. In this paper an iterative method based on the cross-entropy is proposed for this choice. The equations are given that allow to derive the biasing conditions from the simulation itself. The application of the proposed method to three different sample cases, referring to one transient scenario (finite time horizon and prescribed initial conditions) and two stationary cases, shows that the method is quite accurate and that during the path towards overflow the buffer fills mostly in the first phases. (c) 2005 Elsevier B.V. All rights reserved
Big data e privacy by design. Anonimizzazione, pseudonimizzazione, sicurezza. Con Contenuto digitale per download e accesso on line
No full textMETODO DI STIMA DEL PREZZO DI ESERCIZIO DI UN TITOLO DERIVATO E DISPOSITIVO DI ELABORAZIONE ELETTRONICA CHE REALIZZA TALE METODO
No full textMr X vs. Mr Y: The emergence of externalities in differential privacy
No full textThe application of differential privacy requires the addition of Laplace noise, whose level must be measured out to achieve the desired level of privacy. However, the protection of the data concerning a Mr. X, i.e., its privacy level, also depends on the other data contained in the database: a negative externality is recognized. In this paper we show that an attack on Mr. X can be conducted by an oracle, by computing the likelihood ratio under two scenarios, where the database population is made of either independent or correlated entries. We show that the target Mr. X can be spotted, notwithstanding the addition of noise, when its position happens to be eccentric with respect to the bulk of the database population
The role of SHALL and SHOULD in two international treaties: the UN Charter (1948) and the European Convention on Human Rights (1950).
No full textThe aim of the study is to analyse the language if two international treaties: The United Nation Charter (1945) and the European Convention of HumanRights (1950). In particular, it investigates the value of 'shall' and 'Should' in the institutional language of the United Nation and of the Council of Europe through a comparison between the English version of the documents and their Italian translations. The contrastive analysis will provide evides of difficulties encountered in the interpretation of the value and the meaning of modal auxiliary verbs in different language
- …
