Browsing by Subject "data management"
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Item In Reputation We Believe: Query Processing in Mobile Ad-Hoc Networks(IEEE, 2004-08-22) Perich, Filip; Kagal, Lalana; Joshi, Anupam; Finin, Tim; Yesha, YelenaCurrent research on data management in mobile ad-hoc networks focuses on discovering sources and acquiring information. In this mode of operation, mobile devices assume answers to be correct and do not verify the veracity of the information or their providers. This assumption is suitable for most client-server environments; however, peer-to-peer environments lack the intrinsic stability of ``anchored'' sources. In mobile peer-to-peer environments, some sources may provide faulty information, which can lead to incorrect conclusions. Consequently, devices need a mechanism to evaluate the integrity of their peers and the accuracy of peer provided information. To address this problem we propose a query processing model that relies on distributed trust and belief. In our model, each device maintains and shares beliefs regarding the degree of trust it has for its peers -- where trust is determined by experience and reputation. Additionally, each device associates a value indicating its belief in the accuracy of the information the device holds. Each device, when querying its peers, uses the trust it has placed in the peers, in conjunction with the peers' accuracy belief of their information, to determine the reliability of the responses to its query. We have implemented our model in GloMoSim and provide experimental results for different combinations of trust and accuracy algorithms.Item Issues in Data Management for Pervasive Environments(2002-01-12) Avancha, Sasikanth; Chakraborty, Dipanjan; Chen, Harry; Kagal, Lalana; Perich, Filip; Joshi, AnupamA new vista is open for research in the area of data management in pervasive environments where mobile devices gather and exchange information from other devices based on their current context. Each device is both a data source and a data consumer pursuing its individual and collective tasks. Our research group is investigating various ideas aimed at realizing pervasive computing systems based on the cooperation of autonomous, dynamic and adaptive components located in vicinity of one another. These systems will enable devices to discover information, compose it, and analyze it for consistency, all in a secure and trusted manner.Item Numi: A Framework for Collaborative Data Management in a Network of InfoStations(2002-11-20) Kodeswaran, Sethuram Balaji; Ratsimor, Olga Vladi; Joshi, Anupam; Finin, Tim; Yesha, YelenaA network of infostations offering high bandwidth islands of data connectivity has often been suggested as a viable alternative to cellular WAN for providing network connectivity for mobile devices. Current data management models proposed for such networks treat these infostations mainly as passive entities that offer devices in range, access to needed information. In this paper, we propose a novel approach wherein infostations actively participate in delivering content even to devices that are not in range. Other participating mobile devices that have excess spare capacity are used as carrier nodes to transport data towards remote devices. Short range wireless technologies enabling creation of ad-hoc peer-to-peer networking capabilities between devices are used to form transient communities to exchange information. The infostations are responsible for selecting appropriate carrier devices to use so that these carriers meet the device in need at the appropriate time to participate in this collaboration. Through this, dependency on the more expensive WAN networks is minimized. We present a design of our proposed framework and its components along with a prototype implementation.