02212nas a2200193   4500008004100000245009100041210006900132260000900201300001400210490000600224520150300230653004301733653001701776653002601793653002501819653003901844100001801883856011701901       2007                        eng d00aQuerying unstructured and structured peer-to-peer networks: Models, issues, algorithms0 aQuerying unstructured and structured peertopeer networks Models   c2007  a201 - 2100 v53 aPeer-to-Peer (P2P) networks are defined as a collection of peers that expose client/server functionalities simultaneously. P2P systems, built on top of P2P networks, support information sharing primitives and lookup mechanisms of data objects located on peers. It has been demonstrated that the P2P paradigm is able to efficiently capture models and, above all, dynamics of modem applications, beyond limitations of conventional produce/consumer paradigms. Traditionally, P2P primitives and mechanisms have been implemented by means of keyword-based search and matching operations. Modern P2P systems require more complex query functionalities, beyond capabilities of DBMS-inspired models and algorithms. As a consequence, the issue of efficiently querying the underling P2P network is gaining momentum in the research community. Indeed, querying P2P networks, which can be in the unstructured and structure modes, plays a critical role in next-generation P2P systems, as its performance heavily affect the efficiency of the overall system. Starting from these considerations, in this paper we propose a survey on models, issues and algorithms for querying unstructured and structured P2P systems. We also put in evidence similarities and differences of state-of-the-art proposals appearing in literature, with critical discussion, and we provide a rigorous taxonomy of P2P query strategies. Finally, we complete our analytical contribution via hihlighting future directions in this research field.10aIssues and algorithms for P2P networks10aQuery models10aQuerying P2P networks10aRouting P2P networks10aTaxonomies of P2P query strategies1 aCuzzocrea, A.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-44949141961&partnerID=40&md5=6ec618e515388beb0fc88c49914b805800470nas a2200121   4500008004100000245007400041210006900115260000900184300001400193490000600207100001800213856011700231       2007                        eng d00aSpecial issue on "Advances in querying non-conventional date sources"0 aSpecial issue on Advances in querying nonconventional date sourc  c2007  a178 - 1790 v51 aCuzzocrea, A.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-44949092229&partnerID=40&md5=28170025218311b3a1d87a2ec56ac3ab