Mobile Information Systems - Volume 2, issue 1

Article Type: Other

Citation: Mobile Information Systems, vol. 2, no. 1, pp. 1-1, 2006

Authors: Abawajy, J.H. | Deris, M. Mat | Omar, M.

Article Type: Research Article

Abstract: Mobile computing has enabled users to seamlessly access databases even when they are on the move. Mobile computing environments require data management approaches that are able to provide complete and highly available access to shared data at any time from any where. In this paper, we propose a novel replicated data protocol for achieving such goal. The proposed scheme replicates data synchronously over stationary sites based on three dimensional grid structure while objects in mobile sites …are asynchronously replicated based on commonly visited sites for each user. This combination allows the proposed protocol to operate with less than full connectivity, to easily adapt to changes in group membership and not require all sites to agree to update data objects at any given time, thus giving the technique flexibility in mobile environments. 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. Show more

Citation: Mobile Information Systems, vol. 2, no. 1, pp. 3-19, 2006

Authors: Kovács, Benedek | Szalay, M. | Imre, S.

Article Type: Research Article

Abstract: This paper discusses the improvements and parameter optimization issues of LTRACK, a recently proposed mobility management algorithm. Mathematical modelling of the algorithm and the behavior of the Mobile Node (MN) are used to optimize the parameters of LTRACK. A numerical method is given to determine the optimal values of the parameters. Markov chains are used to model both the base algorithm and the so-called loop removal effect. An extended qualitative and quantitative analysis is carried out to …compare LTRACK to existing handover mechanisms such as MIP, Hierarchical Mobile IP (HMIP), Dynamic Hierarchical Mobility Management Strategy (DHMIP), Telecommunication Enhanced Mobile IP (TeleMIP), Cellular IP (CIP) and HAWAII. LTRACK is sensitive to network topology and MN behavior so MN movement modelling is also introduced and discussed with different topologies. The techniques presented here can not only be used to model the LTRACK algorithm, but other algorithms too. There are many discussions and calculations to support our mathematical model to prove that it is adequate in many cases. The model is valid on various network levels, scalable vertically in the ISO-OSI layers and also scales well with the number of network elements. Show more

Keywords: LTRACK, mobility management, location tracking, Markov chain

Citation: Mobile Information Systems, vol. 2, no. 1, pp. 21-50, 2006

Authors: Bottoni, Paolo | De Rosa, Fabio | Hoffmann, Kathrin | Mecella, Massimo

Article Type: Research Article

Abstract: In emergency scenarios we can obtain a more effective coordination among team members, each of them equipped with hand-held devices, through the use of workflow management software. Team members constitute a Mobile Ad-hoc NETwork (MANET), whose topology both influences and is influenced by the workflow. In this paper we propose an algebraic approach for modeling workflow progress as well as its modifications as required by topology transformations. The approach is based on Algebraic Higher-Order Nets and …sees both workflows and topologies as tokens, allowing their concurrent modification. Show more

Keywords: Mobile Ad-hoc NETworks (MANETs), adaptive workflow management, algebraic approaches

Citation: Mobile Information Systems, vol. 2, no. 1, pp. 51-76, 2006

Authors: Ishak, Ruzana | Salleh, Shaharuddin | Olariu, Stephan | Aziz, Mohd.Ismail Abdul

Article Type: Research Article

Abstract: Wireless sensor network refers to a group of sensors, linked by a wireless medium to perform distributed sensing task. The primary interest is their capability in monitoring the physical environment through the deployment of numerous tiny, intelligent, wireless networked sensor nodes. Our interest consists of a sensor network, which includes a few specialized nodes called processing elements that can perform some limited computational capabilities. In this paper, we propose a model called SPLAI that allows the …network to compute a finite element problem where the processing elements are modeled as the nodes in the linear triangular approximation problem. Our model also considers the case of some failures of the sensors. A simulation model to visualize this network has been developed using C++ on the Windows environment. Show more

Keywords: Wireless sensor network, corona, wedges, routing and finite element method

Citation: Mobile Information Systems, vol. 2, no. 1, pp. 77-92, 2006