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| 55. |
- Katchaounov, Timour, et al.
(författare)
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Interface Capabilities for Query Processing in Peer Mediator Systems
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A peer mediator system (PMS) is a decentralized mediator system based on the P2P paradigm, where mediators integrate data sources and other mediators through views defined in a multi-mediator query language. In a PMS mediator peers compose views in terms of views in other peers - mediators and sources, or directly pose queries in the multi-mediator query language to some peer. All peers are fully autonomous and there is no central catalog or controller. Each peer in a PMS must provide an interface to its data and meta-data sufficient to allow the cooperative processing of queries by the PMS. We analyze the computational capabilities and meta-data that a software system has to export in order to participate as a peer in a PMS. For the analysis we identify and compare six classes of peer interfaces with increasing complexity. For each class we investigate the performance and scalability implications that result from the available capabilities and required meta-data. Our results are two-fold: \emphi) we provide guidelines for the design of mediator peers that can make best use of the interfaces provided by the data sources, and \emphii) we analyze the tradeoffs in the design of inter-mediator interfaces so that mediator peers can efficiently cooperate to process queries against other composed mediators. Finally we describe the choices made in a concrete implementation of a PMS.
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| 56. |
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- Katchaounov, Timour, 1969-
(författare)
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Query Processing for Peer Mediator Databases
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The ability to physically interconnect many distributed, autonomous and heterogeneous software systems on a large scale presents new opportunities for sharing and reuse of existing, and for the creataion of new information and new computational services. However, finding and combining information in many such systems is a challenge even for the most advanced computer users. To address this challenge, mediator systems logically integrate many sources to hide their heterogeneity and distribution and give the users the illusion of a single coherent system. Many new areas, such as scientific collaboration, require cooperation between many autonomous groups willing to share their knowledge. These areas require that the data integration process can be distributed among many autonomous parties, so that large integration solutions can be constructed from smaller ones. For this we propose a decentralized mediation architecture, peer mediator systems (PMS), based on the peer-to-peer (P2P) paradigm. In a PMS, reuse of human effort is achieved through logical composability of the mediators in terms of other mediators and sources by defining mediator views in terms of views in other mediators and sources. Our thesis is that logical composability in a P2P mediation architecture is an important requirement and that composable mediators can be implemented efficiently through query processing techniques. In order to compute answers of queries in a PMS, logical mediator compositions must be translated to query execution plans, where mediators and sources cooperate to compute query answers. The focus of this dissertation is on query processing methods to realize composability in a PMS architecture in an efficient way that scales over the number of mediators. Our contributions consist of an investigation of the interfaces and capabilities for peer mediators, and the design, implementation and experimental study of several query processing techniques that realize composability in an efficient and scalable way.
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| 58. |
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| 59. |
- Ketabchi, M.A, et al.
(författare)
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Comparative analysis of RDBMS and OODBMS: a case study
- 1990
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Ingår i: Proc. of the COMPCON IEEE Computer Society International Conference.
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Konferensbidrag (refereegranskat)abstract
- The underlying hypothesis of the case study described in this article is that the development, implementation, operations, and maintenance of large complex data intensive applications such as computer integrated manufacturing can be simplified through the use of object-oriented DBMS. The objective of the case study is to verify this hypothesis.The approach of the case study is to prototype selected representative components of a computer integrated manufacturing system, which have been developed on top of a relational DBMS, using an object-oriented DBMS.The results of the study illustrate that the object-oriented prototype has a superior schema, is capable of providing convenient access to information, and is easier to extend and maintain.
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