Review of Some Transaction Models used in Mobile Databases

Mobile computing is presently experiencing a period of unprecedented growth with the convergence of communication and computing capabilities of mobile phones and personal digital assistant. However, mobile computing presents many inherent problems that lead to poor network connectivity. To overcome poor connectivity and reduce cost, mobile clients are forced to operate in disconnected and partially connected modes. One of the main goals of mobile data access is to reach the ubiquity inherent to the mobile systems: to access information regardless of time and place. Due to mobile systems restrictions such as, for instance, limited memory and narrow bandwidth, it is only natural that researchers expend efforts to soothe such issues. This work approaches the issues regarding the cache management in mobile databases, with emphasis in techniques to reduce cache faults while the mobile device is either connected, or with a narrow bandwidth, or disconnected at all. Thus, it is expected improve data availability while a disconnection. Here in the paper, we try to describe various mobile transaction models, focusing on versatile data sharing mechanisms in volatile mobile environments

Review of Some Transaction Models used in Mobile Databases

Mobile computing is presently experiencing a period of unprecedented growth with the convergence of communication and computing capabilities of mobile phones and personal digital assistant. However, mobile computing presents many inherent problems that lead to poor network connectivity. To overcome poor connectivity and reduce cost, mobile clients are forced to operate in disconnected and partially connected modes. One of the main goals of mobile data access is to reach the ubiquity inherent to the mobile systems: to access information regardless of time and place. Due to mobile systems restrictions such as, for instance, limited memory and narrow bandwidth, it is only natural that researchers expend efforts to soothe such issues. This work approaches the issues regarding the cache management in mobile databases, with emphasis in techniques to reduce cache faults while the mobile device is either connected, or with a narrow bandwidth, or disconnected at all. Thus, it is expected improve data availability while a disconnection. Here in the paper, we try to describe various mobile transaction models, focusing on versatile data sharing mechanisms in volatile mobile environments

Building distributed heterogeneous smart phone Java applications an evaluation from a development perspective

The advances in mobile phone technology have enabled such devices to be programmed to run general-purpose applications using a special edition of the Java programming language. Java is designed to be a heterogeneous programming language targeting different platforms. Such ability when coupled with the provision of high-speed mobile Internet access would open the door for a new breed of distributed mobile applications. This paper explores the capabilities and limitations of this technology and addresses the considerations that must be taken when designing and developing such distributed applications. Our findings are verified by building a test client-server system where the clients in this system are mobile phones behaving as active processing elements not just mere service requesters

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

Context-sensitive mobile database summarisation

In mobile computing environments, as a result of the reduced capacity of local storage, it is commonly not feasible to replicate entire datasets on each mobile unit. In addition, reliable, secure and economical access to central servers is not always possible. Moreover, since mobile computers are designed to be portable, they are also physically small and thus often unable to hold or process the large amounts of data held in centralised databases. As many systems are only as useful as the data they can process, the support provided by database and system management middleware for applications in mobile environments is an important driver for the uptake of this technology by application providers and thus also for the wider use of the technology. One of the approaches to maximize the available storage is through the use of database summarisation. To date, most strategies for reducing data volumes have used compression techniques that ignore the semantics of the data. Those that do not use data compression techniques adopt structural (i.e. data and use-independent) methods. In this paper, we outline the special constraints imposed on storing information in mobile databases and provide a flexible data summarisation policy. The method works by assigning a level of priority to each data item through the setting of a number of parameters. The paper discusses some policies for setting these parameters and some implementation strategies.Bedford Park, South Australi

Supporting disconnected operations in mobile computing

Mobile computing has enabled users to seamlessly access databases even when they are on the move. However, in the absence of readily available high-quality communication, users are often forced to operate disconnected from the network. As a result, software applications have to be redesigned to take advantage of this environment while accommodating the new challenges posed by mobility. In particular, there is a need for replication and synchronization services in order to guarantee availability of data and functionality, (including updates) in disconnected mode. To this end we propose a scalable and highly available data replication and management service. The proposed replication technique is compared with a baseline replication technique and shown to exhibit high availability, fault tolerance and minimal access times of the data and services, which are very important in an environment with low-quality communication links.<br /

Transaction Management Model for Mobile Database

Transaction support is crucial in mobile data management. Specific characteristics of mobile environments (e.g. variable bandwidth, disconnections, and limited resources on mobile hosts) make traditional transaction management techniques no longer appropriate. This is due the fact that the Atomicity, Consistency, Isolation and Durability (ACID) properties of transactions are not simply followed, in particular the consistency property. Thus, transaction management models adopting weaker form of consistency are needed and these models can now tolerate a limited amount of consistency. As a result, several transaction management models for mobile databases have been proposed, each of which has attempted to overcome some issues pertaining to transaction processing in mobile environment. However, issues such as (a) only one mobile host (MH) is allowed to update the data item (b) large number of rejected transactions (c) commit time execution of transactions at mobile host (MH) is large are not well handled. The proposed the model with the aims at solving the stated issues. The main idea underlying the model is that transaction execution can be done at the base station (BS) and mobile host (MHs). Transactions at a MH can update data locally and then precommit. When the MH connects to the BS, these pre-committed transactions are sent to the BS and re-executed as base transactions (BT) to maintain data consistency at the BS. BTs are serialized on the master data stored at the BS. This will results in data consistency. The availability of data item at MHs makes the execution of transaction at MHs possible. Each MH is allocated some value of data item, and the rest of it is kept at the base server. By having the own this resource, a transaction at a MH is allowed to update the data item within the limit of iSi. The model has been implemented and the result has shown that the model works correctly as expected

Context-Awareness Enhances 5G Multi-Access Edge Computing Reliability

The fifth generation (5G) mobile telecommunication network is expected to support Multi- Access Edge Computing (MEC), which intends to distribute computation tasks and services from the central cloud to the edge clouds. Towards ultra-responsive, ultra-reliable and ultra-low-latency MEC services, the current mobile network security architecture should enable a more decentralized approach for authentication and authorization processes. This paper proposes a novel decentralized authentication architecture that supports flexible and low-cost local authentication with the awareness of context information of network elements such as user equipment and virtual network functions. Based on a Markov model for backhaul link quality, as well as a random walk mobility model with mixed mobility classes and traffic scenarios, numerical simulations have demonstrated that the proposed approach is able to achieve a flexible balance between the network operating cost and the MEC reliability.Comment: Accepted by IEEE Access on Feb. 02, 201