Mobile Data Management

The management of data in the mobile computing environment offers new challenging problems. Existing software needs to be upgraded to accommodate this environment. To do so, the critical parameters need to be understood and defined. We have surveyed some problems and existing solution

Information Technology and Computer Science

Abstract-Within the last decade, the continuous development of mobile technology has motivated an intense research in mobile data services. Among these services, location-based services and location-dependant queries have attracted a lot of attention from the software industry as well as from researchers. Although a number of locations based service methods have been proposed, the performance is not satisfactory in the case of dynamic data management problems that introduce high overhead in update and query operations. In this paper, we introduce a proxy based distributed dynamic data management architecture for location based services that reduces network cost with required quality of service (QoS). The system proposes a distributed hierarchical database structure with collocated proxy for efficient service delivery to location-dependant queries especially Range Queries (RQ). The system that we propose have the following advantages. i) It performs efficient processing of location dependant queries, especially Range Queries spanning over multiple network cells ii) It reduces wireless communication between mobile devices and servers. iii) The system is scalable where location data is distributed and arranged hierarchically. We use proxy objects to carry out processing task for each mobile user. Thus proxies play an important role and in charge of routing the queries to different (distributed) databases and present the results to queries efficiently. Simulation study shows the effectiveness of our proposed architecture

Updates in Highly Unreliable, Replicated Peer-to-Peer Systems

In this paper we study the problem of updates in truly decentralised and self-organising systems such as pure P2P systems. We assume low online probabilities of the peers (Full Document</a

Investigação e implementação de estratégias de notificação de invalidação para coerência de cache em ambientes de computação móvel sem fio

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Ciência da ComputaçãoA computação móvel está se tornando um ambiente de uso comum nos dias atuais. Desta forma é importante fornecer aos seus usuários serviços com uma qualidade similar à encontrada em ambientes cabeados

Design and analysis of object replacement policies on dynamic data allocation and replication algorithm with buffer constraints

Master'sMASTER OF ENGINEERIN

Maintaining cache consistency in mobile computing environments.

by Leung Wing Man.Thesis (M.Phil.)--Chinese University of Hong Kong, 1996.Includes bibliographical references (leaves 73-75).Abstract --- p.iAcknowledgements --- p.iiiChapter 1 --- Introduction --- p.1Chapter 2 --- Background --- p.7Chapter 2.1 --- What is Mobile Computing? --- p.7Chapter 2.1.1 --- Applications of Mobile Computing --- p.8Chapter 2.1.2 --- New Challenges of Mobile Computing --- p.9Chapter 2.2 --- Related Work --- p.12Chapter 2.2.1 --- Lazy Replicated File Service --- p.12Chapter 2.2.2 --- Dividing the Database into Clusters --- p.14Chapter 2.2.3 --- Applying Causal Consistency --- p.15Chapter 2.3 --- Summary --- p.16Chapter 2.4 --- Serializability and Concurrency Control --- p.17Chapter 3 --- System Model and Suggested Protocol --- p.20Chapter 3.1 --- System Model --- p.20Chapter 3.2 --- Cache Management --- p.21Chapter 3.2.1 --- Version Control Mechanism --- p.22Chapter 3.2.2 --- Cache Consistency --- p.22Chapter 3.2.3 --- Request Data from Servers --- p.25Chapter 3.2.4 --- Invalidation Report --- p.27Chapter 3.2.5 --- Data Broadcasting --- p.30Chapter 4 --- Simulation Study --- p.32Chapter 4.1 --- Physical Queuing Model --- p.32Chapter 4.2 --- Logical System Model --- p.33Chapter 4.3 --- Parameter Setting --- p.34Chapter 4.4 --- The Significance of the Length of Invalidation Range --- p.37Chapter 4.4.1 --- Performance with Different Invalidation Range --- p.38Chapter 4.4.2 --- Increasing the Update Frequency --- p.40Chapter 4.4.3 --- Impact of Piggybacking Popular Data --- p.41Chapter 4.4.4 --- Increasing the Disconnection Period --- p.42Chapter 4.5 --- Comparison of the Proposed Protocol with the Amnesic Terminal Protocol --- p.44Chapter 4.5.1 --- Setting a Short Timeout Period --- p.45Chapter 4.5.2 --- Extending the Timeout Period --- p.46Chapter 4.5.3 --- Increasing the Frequency of Temporary Disconnection --- p.48Chapter 4.5.4 --- Increasing the Frequency of Crossing Boundaries --- p.49Chapter 4.6 --- Evaluate the Performance Gain with Piggybacking Message --- p.50Chapter 4.6.1 --- Adding Piggybacking Messages --- p.51Chapter 4.6.2 --- Reducing the Number of Popular Data --- p.52Chapter 4.6.3 --- Increasing the Frequency of Updates --- p.53Chapter 4.7 --- Behaviour of the Proposed Protocol --- p.54Chapter 4.7.1 --- Finding Maximum Number of Mobile Computers --- p.54Chapter 4.7.2 --- Interchanging the Frequency of Read-Only and Update Transactions --- p.55Chapter 5 --- Partially Replicated Database System --- p.57Chapter 5.1 --- Proposed Amendments --- p.57Chapter 5.1.1 --- Not Cache Partially Replicated Data ( Method 1 ) --- p.58Chapter 5.1.2 --- Drop Partially Replicated Data ( Method 2 ) --- p.59Chapter 5.1.3 --- Attaching Server-List ( Method 3 ) --- p.59Chapter 5.2 --- Experiments and Interpretation --- p.60Chapter 5.2.1 --- Partially Replicated Data with High Accessing Probability --- p.61Chapter 5.2.2 --- Reducing the Cache Size --- p.64Chapter 5.2.3 --- Partially Replicated Data with Low Accessing Probability --- p.65Chapter 6 --- Conclusions and Future Work --- p.70Chapter 6.1 --- Future Work --- p.72Bibliography --- p.73Chapter A --- Version Control Mechanism for Servers --- p.7