اطلاعات تلفن همراه و مدیریت معامله

Mobile computing paradigm has emerged due to advances in wireless or cellular networking technology. This rapidly expanding technology poses many challenging research problems in the area of mobile database systems. The mobile users can access information independent of their physical location through wireless connections. However, accessing and manipulating information without restricting users to specific locations complicates data processing activities. There are computing constraints that make mobile database processing different from the wired distributed database computing. In this paper, we survey the fundamental research challenges particular to mobile database computing, review some of the proposed solutions and identify some of the upcoming research challenges. We discuss interesting research areas, which include mobile location data management, transaction processing and broadcast, cache management and replication and query processing. We highlight new upcoming research directions in mobile digital library, mobile data warehousing, mobile workflow and mobile web and e-commerce.

The rapid technological advancements in cellular communications, wireless LAN and satellite services have led to the emergence of mobile computing [11]. In mobile computing, users are not attached to a fixed geographical location; instead their point of attachment to the network changes as they move. The emergence of relatively sophisticated low-power, low-cost and portable computing platforms such as laptops and personal digital assistants (PDA) have made possible for people to work from anywhere at any time (from their offices, homes and while travelling) via wireless communication network. As the technology advancing, millions of users carry portable computer and communicator devices that use a wireless connection to access worldwide global information network. Each mobile unit equipped with wireless network can be connected to global information network to provide unrestricted user mobility. Mobility and portability pose new challenges to the mobile database management and distributed computing [34]. The database software support for mobile computing is still in the germinating stage. There is necessity to design specifications for energy efficient data access methodologies and in general develop database software systems that extend existing database systems designs and platforms to satisfy the constraints imposed by mobile computing (see Fig. 1). How to handle long period of disconnection, and other constrained resources of mobile computing such as limited battery life and variable bandwidth etc.? In mobile computing, there will be more competition for shared data since it provides users with ability to access information and services through wireless connections that can be retained even while the user is moving. Further, mobile users will have to share their data with others. The task of ensuring consistency of share data becomes more difficult in mobile computing because of limitations and restrictions of wireless communication channels. Some of the several questions need to be answered are how mobile computing differs from distributed database computing? How does mobility affect transaction processing and replication? Is location management a database management problem? How to replicate the location data? Caching is key to handle frequent disconnection in mobile computing. How to keep cache consistent with minimum communication cost? Is the weaker notion of consistency more appropriate? How query processing is different in mobile computing environment? In this paper, we discuss some of the problems identified with mobile database computing and review proposed solutions, and explore the upcoming research challenges. Some of the problems involved in supporting transaction services and distributed data management in a mobile environment has been identified in [2], [8], [34] and [46]. At the time of submitting this paper, we found a recent survey, which is very specific towards data dissemination, location-dependent query and advanced interfaces for mobile computers in [8]. Our survey here is much more comprehensive and gives elaborate coverage of wide variety of research issues in mobile data management, not reported in [8]. Also, we categorize mobile database research and discuss future research issues and applications on mobile platform, again not covered in [8]. The rest of the paper is organized as follows. Section 2 discusses the mobile database architecture. We highlight data processing and mobile constraints issues in Section 3. In Section 4, we give in depth treatment to various the mobile data management issues. Section 5 discusses transaction processing in mobile databases. In Section 6, we explore upcoming mobile database research directions. We conclude in Section 7.

Management of data in the mobile computing environment offers new challenging problems. Existing DBMS software need to be upgraded to adapt them to the new environment. To be able to do so, the critical parameters need to be understood and defined. Mobility brings in new dimension to the existing solutions to the problems in distributed databases. We have surveyed some of the problems and existing solutions in that direction. We have highlighted the merits and demerits of existing solutions. We have identified some of the upcoming research areas that require rethinking due to nature and constraints of mobile computing environment. The upcoming mobile database research directions discussed here will be the centres of attractions among mobile database researchers in years to come. There is a need to explore these issues further and improve the existing solutions offered in that direction.