52874049
Negotiating data access in federated database systems
A protocol is presented for negotiating access to data in a federated database. This protocol deals with several important aspects of data sharing in an environment where databases belonging to different organizations coexist and cooperate. It is based on the concept of quasicopies. These are cached values that are allowed to deviate from the central value in a controlled fashion. The degree of consistency of a quasicopy is established by the entity where the quasicopy is to reside. Two techniques are presented that can be used for numerical data and for copies that rely on version numbers. It is believed that these two ideas encompass many of the interesting cases in practice. However, it is also possible to fine tune the estimation of this function once the exact semantics of the data involved are known.<<ETX>>
29614860
A mobile computer interface for heterogeneous databases
Computer-based personal information services are evolving beyond simple applications such as retrieval of phone numbers to include interaction with collections of large, heterogeneous, geographically distributed information bases. Concurrently, small, pen-based, mobile computers are becoming the machine of choice for personal computing. This latter trend suggests simple interfaces that are easy-to-use, avoid keyboard use, and are suited for the small screens and small memory sizes of mobile machines. The former trend, however, suggests an increased sophistication in database interfaces, so as to provide access to the more complex heterogeneous collection of databases that are now part of a personal information service. At the Matsushita Information Technology Laboratory (MITL) they are working on a pen-based graphical database language that begins to combine these conflicting demands for simplicity and sophistication. The authors sketch the highlights of the research approach, and present a brief description of the current prototype.<<ETX>>
41657422
Long-Term Caching Strategies for Very Large Distributed File Systems
206600407
Profile-Based Security Against Malicious Mobile Agents
In this paper we describe a security system against malicious agents in a wireless ad hoc network. This system monitors the activities of mobile agents. By mining the log data, the system builds dynamic behavioral profiles for each class of agents. The profiles are then used to classify each agent instance and detect anomalous agents. The malicious nature of identified anomalous agents are further determined by a threat assessment module. For mobile agent profiling, we presented two approaches: one based on rule-learning and another on histograms of features related each agent class. We have implemented a prototype system using the histogram-based approach. The prototype is also described in the paper.
62611509
Query optimization in distributed databases through load balancing
Abstract : As technology advances, computing environments composed of large numbers of workstations and mainframes connected by a high bandwidth local area network become attractive. These systems typically support a large number of application classes, and the heterogeneity of their workload, coupled with the decentralization of the systems, can lead to load imbalances across the network. This work attempts to study the benefits of load balancing strategies in the context of a particular application, distributed database systems. It was felt that, by focusing on a specific area, the problem would become more tractable. The choice of database management systems can be justified not only by their intrinsic importance, but also by the adaptability of load balancing strategies to query optimization algorithms. In order to determine whether load balancing strategies can indeed be adapted to current optimizers with a moderate amount of effort and to see whether the resulting performance benefits are sizable, both benchmarking and simulation experiments were carried out.
16077675
Hybrid Multi-agent Systems: Integrating Swarming and BDI Agents
The individual agents that interact in a multi-agent system typically exist along a continuum ranging from heavyweight cognitive agents (often of the "BDI" type) to lightweight agents with limited individual processing (digital ants). Most systems use agents from a single position along this spectrum. We have successfully implemented several systems in which agents of very different degrees of internal sophistication interact with one another. Based on this experience, we identify several different ways in which agents of different kinds can be integrated in a single system, and offer observations and lessons from our experiences.
42014672
Trade Press News - Announcement and Preface
29591299
Trade Press News