dIn this paper, we present the design and implementation of a VRML97 multi-user layer, which is introduced in the EVE distributed virtual reality platform. Though other approaches use a VRML node insertion mechanism, ...
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dIn this paper, we present the design and implementation of a VRML97 multi-user layer, which is introduced in the EVE distributed virtual reality platform. Though other approaches use a VRML node insertion mechanism, Such as VSPLUS, or a substitution mechanism, Such as SPIN-3D, our approach uses a removal mechanism. Main consideration of our multi-user extension is the ease of transforming single-user virtual worlds into multi-user virtual worlds, as well as the conformity with any standard VRML97 browser. Furthermore, we present the EVE' s communication platform, which can be used in order to support Collaborative Virtual Environments. Main issues regarding the effective network communication as well as the initialization of the 3D scene are discussed in this paper. (C) 2003 Elsevier Ltd. All rights reserved.
Motivated by the wavelength assignment problem in WDM optical networks, we study path coloring problems in graphs. Given a set of paths P on a graph G, the path coloring problem is to color the paths of P so that no t...
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In this paper we demonstrate the significant impact of (a) the mobility rate and (b) the user density on the performance of routing protocols in ad-hoc mobile networks. In particular, we study the effect of these para...
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In this paper we demonstrate the significant impact of (a) the mobility rate and (b) the user density on the performance of routing protocols in ad-hoc mobile networks. In particular, we study the effect of these parameters on two different approaches for designing routing protocols: (a) the route creation and maintenance approach and (b) the "support" approach, that forces few hosts to move acting as "helpers" for message delivery. We study one representative protocol for each approach, i.e., AODV for the first approach and RUNNERS for the second. We have implemented the two protocols and performed a large scale and detailed simulation study of their performance. For the first time, we study AODV (and RUNNERS) in the 3D case. The main findings are: the AODV protocol behaves well in networks of high user density and low mobility rate, while its performance drops for sparse networks of highly mobile users. On the other hand, the RUNNERS protocol seems to tolerate well (and in fact benefit from) high mobility rates and low densities. Thus, we are able to partially answer an important conjecture of [Chatzigiannakis, I et al. (2003].
In this paper we challenge the question of whether there is value in having multiple layers of semantic information associated with corpus semantic annotation. In this context we introduce a semantic annotation experi...
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ISBN:
(纸本)2951740816
In this paper we challenge the question of whether there is value in having multiple layers of semantic information associated with corpus semantic annotation. In this context we introduce a semantic annotation experiment in which novice annotators were asked to assign sense tags to a set of polysemous corpus nouns, using Wordnet as their referential sense repository. Wordnet is a rich sense inventory that provides explicit information of the semantic types associated with every word sense. To measure the effect semantic types' knowledge has on the sense assignment process, we carried out two annotation sessions. In the first session, annotators relied exclusively on Wordnet synsets to annotate corpus nouns, whereas in the second session the same pool of annotators examined Wordnet synsets in conjunction with their semantic types, prior assigning a sense tag. Comparing annotators' performance in both sessions shows that when consulting semantic types, annotators assigned more salient senses to highly polysemous nouns, whereas for the same set of terms, when relying exclusively on Wordnet synsets, annotators tended to assign narrower senses, which whatsoever were more error-prone. Results indicate that semantic types have a potential in dealing with subtle sense distinctions in the course of corpus annotation.
Fairly rapid environmental changes call for continuous surveillance and on-line decision making. There are two main areas where IT technologies can be valuable. In this paper we present a multi-agent system for monito...
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In this paper we consider two random graph models and their relationship. More specifically, we consider the random graph model Gn,m, where a random graph is constructed by drawing uniformly and independently m edges ...
We consider optimal itinerary problems in time-table information systems supporting a vast number of on-line queries. We exhibit two important extensions of the time-dependent approach to model realistic versions of t...
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In this work we study how to process complex queries in DHT-based Peer-to-Peer (P2P) data networks. Queries are made over tuples and relations and are expressed in a query language, such as SQL. We describe existing r...
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As the size of the Web grows, it becomes an imperative to equip search engines with sophisticated indexing modules in order to enable a meaningful organization of the stored data. In this paper we present a structured...
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ISBN:
(纸本)2951740816
As the size of the Web grows, it becomes an imperative to equip search engines with sophisticated indexing modules in order to enable a meaningful organization of the stored data. In this paper we present a structured multilingual conceptual repository that has been employed as the backbone of a conceptual indexing and retrieval system. Our conceptual warehouse originates from a multilingual semantic network (Balkanet) and its Inter-Lingual-Index, which was enriched with domain ontology information inherited from the SUMO ontology. We report on the ontology's design principles and provide a description of its structure. We argue that an important attribute of the Balkanet's ILI is its flexibility in incorporating new concepts and/or languages by allowing the percolation of shared semantic attributes to all concepts represented within taxonomies. We further present our approach to conceptual indexing, and introduce an indexing algorithm that utilizes Balkanet's classified conceptual taxonomies. Finally, we discuss how conceptual taxonomies can help retrieval algorithms in making links between terms used in search requests and semantically related terms that might be found in the indexed documents.
In this paper, we present the design, implementation and evaluation of FESMI, a fuzzy expert system that deals with diagnosis and treatment of male impotence. The diagnosis process, linguistic variables and their valu...
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