Search

We present a fully automatic and weighted dictionary to be used in topical opinion retrieval. We also de?ne a simple topical opinion retrieval function that is free from parameters, so that the retrieval does not need any learning or tuning phase

In order for Web services to be able to fully exploit the advantages of dynamic binding, requesting agents must be given a way to select the most "convenient" service at invoke time. Current techniques do not address the problem of selecting services that best fit a requester' needs. In this paper, we propose an extension of the UDDI specification in order to provide and exploit predictions about the behavior of Web services. Such values/parameters are expressed in terms of availability, reliability and completion time. The computed predictions are used by requesting agents to implement an effective dynamic service selection. A prototype, named eUDDIr, implementing such extension has been developed. Our proposal is particularly suited for scenarios where requestors do not wish to explicitly deal with QoS aspects, or in case provider agents have no convenience in building up the infrastructure for guaranteed QoS, but aim to provide services of good quality to their customers. The adoption of eUDDIr can effectively improve the service requestors "satisfaction", in particular when they are involved in a Web services composition process

In the online traveling salesman problem requests for visits to cities (points in a metric space) arrive online while the salesman is traveling. The salesman moves at no more than unit speed and starts and ends his work at a designated origin. The objective is to find a routing for the salesman which finishes as early as possible. We consider the online traveling salesman problem when restricted to the non-negative part of the real line. We show that a very natural strategy is 3/2-competitive which matches our lower bound. The main contribution of the paper is the presentation of a "fair adversary", as an alternative to the omnipotent adversary used in competitive analysis for online routing problems. The fair adversary is required to remain inside the convex hull of the requests released so far. We show that on IR0+ algorithms can achieve a strictly better competitive ratio against a fair adversary than against a conventional adversary. Specifically, we present an algorithm against a fair adversary with competitive ratio (1+√17)/4 ≅ 1:28 and provide a matching lower bound. We also show competitiveness results for a special class of algorithms (called diligent algorithms) that do not allow waiting time for the server as long as there are requests unserved.

In this paper we deal with the problem of designing virtual path layouts in ATM networks with given hop-count and minimum load, for which we prove a lower bound with respect to networks with arbitrary topology. The result is then applied to derive a tight lower bound for the one-to-many communication pattern in networks with arbitrary topology, and for the many-to-many communication pattern in planar graphs and graphs with bounded treewidth.

This paper briefly reports on the results of some testing activities performed at IASI on the efficiency of multimedia conferencing on both local and wide-area packet switched networks. The aim of the testing was to study under which hypothesis it was possible to obtain acceptable - in terms of rate of information exchanged - multimedia conferencing sessions. A specific goal was to verify the possibility of obtaining an acceptable quality by using widely available, cheap resources. The tests performed have been carried out on an Ethernet LAN, connected to Internet by a 64Kbps link, using TCP/IP with multicast extension as transport protocol, in order to avoid IP datagrams multiplication when a multimedia conference involves more than two participants