Database federation is one approach to data integration, in which a middleware, called mediator, provides uniform access to a number of heterogeneous data sources. In this thesis, we focus on the query optimization for distributed joins over database federation. One important observation in query optimization over distributed database system is that run-time conditions (namely available buffer size, CPU utilization in machine and network environment) can significantly affect the execution cost of a query plan. However, in existing database federation systems, very few studies have addressed run-time conditions. It is a challenging problem, because usually the mediator is not able to know the run-time conditions of remote sites and considering run-time conditions will bring about extra complexity to the optimizer. This thesis proposes the Cluster-and-Conquer algorithm for query optimization over database federation while efficiently considering run-time conditions. This algorithm has three-fold benefits. Firstly, the run-time conditions of machines are now available for cluster mediator. Secondly, each cluster mediator can deal with its own sub query concurrently, so the complexity of processing query plan is decreased. Thirdly, the algorithm outperforms other related approaches in terms of“cost of costing", because it removes unnecessary inter-cluster operations in the early stage. I have implemented a prototype data federation system with Cluster-and-Conquer algorithm. The experimental results showed the capabilities and efficiency of our algorithm and described the target scenarios where the algorithm performs better than other related approaches.

Thesis (M.A.)--Ball State University, 2009. / Title from PDF t.p. (viewed on Dec. 14, 2009). Includes bibliographical references (p. [70]-77).

Thesis (M.S. in National Security Affairs)--Naval Postgraduate School, June 2004. / Thesis advisor(s): David S. Yost, Anne Clunan. Includes bibliographical references (p. 71-74). Also available online.

Inaug, Dimm.--Bonn. / Vita. Bibliography: p. xviii-xxviii.

Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, March 2002. / Thesis advisor(s): Lyman Miller, Donald Abenheim. Includes bibliographical references (p. 55-59). Also available online.

Thesis (Ph. D.)--University of Chicago, Dept. of Sociology, August 2003. / Includes bibliographical references. Also available on the Internet.

Thesis (M.A in National Security Affairs)--Naval Postgraduate School, June 2003. / Thesis advisor(s): Lyman Miller, Gaye Christoffersen. Includes bibliographical references (p. 75-79). Also available online.

Cloud Computing is the new trend in sharing resources, sharing and managing data and performing computations on a shared resource via the Internet. However, with the constant increase in demand, these resources are insufficient. So users often use another network in conjunction with the current one. All these networks accom- plish the goal of providing the user with a virtual or physical machine. However, to achieve the result, virtual machine users have to maintain multitude credentials and follow a different process for each network. In this thesis, we focus on SAGEFed, a product that enables a user to use the same credentials and commands to reserve the resources on two different federated clouds, i.e., SAVI and GENI. As a part of SAGEFed, the user can acquire or reserve resources on the clouds with the same API. The same service also manages the credentials, so they do not have to manage different credentials while acquiring resources. Furthermore, SAGEFed demonstrates that any cloud that has some form of client tool can be easily integrated. / Graduate

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The variation in expansion of national political parties into regional politics in Russia poses a fundamental challenge to theories of party development by presenting an empirical puzzle: why have national politics dominated in some regions yet failed to elect or even present candidates in others? Conventional explanations for party weakness in Russia invoke cultural constraints or poor institutional incentives but neither provide sufficient variation to explain these outcomes at the regional level. These failures correspond to a larger lacunae in the party literature on the process by parties become nationalized and eliminate their regional competitors. / This study addresses these empirical questions by re-examining regional elites and their ability to create informal alternatives to parties. I argue that the failure of national political party development in Russian regional politics is not simply the product of poor institutional incentives but rather due to the active opposition of regional elites. Where regional elites successfully mobilized the resources made available during transition, they prevented the entry of national parties by furnishing their own candidates with powerful financial resources and lending them reputation that resonated with the electorate. These outcomes were not predetermined by legacies of the Soviet era, however, but were rather contingent on the ability of regional executives to rapidly construct winning coalitions, particularly through the mobilization of administrative resources and the construction of patronage networks. Hence, the successful development national parties in regional politics was as much a story of weak regional regimes as it was a story of successful regional party branches.