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The increase in the popularity of small digital mobile devices also implies an increased demand in applications. The limited computing capabilities on the mobile devices and the unreliability of wireless links are barriers to the smooth access of mobile devices to the Grid applications and resources. In this paper a proxy-based approach is presented that is able to support various kinds of applications to be used by mobile devices by providing specific-purpose services on the proxy. The implemented prototype that includes some of the realized proxy services and the example client application for a mobile device show the viability of the proposed approach. [ABSTRACT FROM AUTHOR]

Mobile Grid is a branch of Grid where the infrastructure includes mobile devices. The mobile Grid exhibits different challenges such as resource-constraints and users΄ movements, compared to the traditional Grid. Mobile agent is an attractive technology to overcome these challenges. In this paper, we present a new mobile Grid system based on the mobile agent. This paper describes the architecture of the new system: multi-proxy based mobile grid environment with location management and message delivery mechanism. Our system is lightweight enough to be installed on mobile devices. It also provides the physical and logical mobility of mobile agents. We implemented the mobile Grid system based on Globus Toolkit and ODDUGI mobile agent system. [ABSTRACT FROM AUTHOR]

Mobile Grid is a branch of Grid computing where the infrastructure includes mobile devices. Because mobile devices are resource-constrained, mobile Grid should provide new scheduling strategies considering its environment. This paper presents a group-based fault tolerance scheduling algorithm. The algorithm classifies mobile devices into several groups considering characteristic parameters of mobile Grid. Then, it uses an adaptive replication algorithm for enduring faults in an active manner. The experimental results show that our scheduling algorithm provides a superior performance in terms of execution times to the one without considering grouping and fault tolerance. Throughout the experiments, we found that the active fault tolerance (i.e., replication) is essential to improving performance in mobile Grid. [ABSTRACT FROM AUTHOR]

Grid computing using wireless networks is receiving increasing attention and is expected to become a critical part of future grid computing. However, the inherent challenges of mobile environments such as mobility management, disconnected operation, device heterogeneity, service discovery, and resource sharing are significant issues in mobile grid computing. To achieve the best performance in a mobile grid computing environment, the mobile devices with the lowest probability of mobility should be selected for use first. We therefore focus on the idle state of mobile devices and use IP-paging scheme to identify the idle mobile devices. For this, we propose a user-defined checkpoint technique for task migration, which is based on the information of when a mobile device will leave the network or stop due to low battery. Our checkpoint technique performs checkpoints by two conditions: when a mobile device leaves its current cell and when it turns off due to low battery capacity. [ABSTRACT FROM AUTHOR]

Recently mobile devices become considered as grid resources as the technology of mobile devices and wireless communication network improves. But mobile devices have several problems such as instability of wireless communication, intermittent connection, limitation of power supply, and low communication bandwidth. These problems make it difficult to use mobile grid computing resources for stable job processing effectively. For stable resource participation of mobile devices, a monitoring scheme that collects and analyzes dynamic information of mobile devices, such as CPU, memory, storage, network and location, is required. But, if the time interval of monitoring is very short, overhead of collecting information increases. The scheme, however, cannot keep correct state information in dynamic environments if the interval is very long. This paper proposes a monitoring service scheme that adjusts the time interval of monitoring according to the state information predicted by Markov Chain model. [ABSTRACT FROM AUTHOR]

Recently, many studies have attempted to utilize mobile nodes as resources in mobile grids. Due to their underlying restrictions such as intermittent communication disconnections, limited battery capacity, and so on, mobile nodes are less reliable than wired nodes for job processing. Therefore, it is imperative to find an enhanced job scheduling method to provide stable job processing for mobile grids. In this paper, we propose an efficient job scheduling method in mobile grids, which can determine the suitable number of replicas for a job based on resource (mobile node) information, node status, and access point information. In our job scheduling method, mobile nodes are divided into node groups, and the number of subjobs assigned to each node group is derived from the reliability and performance of the node group. Simulation results show that our scheduling algorithms can reduce the makespan of entire jobs in mobile grid environments compared with random-based job scheduling. [ABSTRACT FROM AUTHOR]

The emerging Grid is extending the scope of resources to mobile devices and sensors that are connected through unreliable networks. Nowadays the number of mobile device users is increasing dramatically and the mobile devices provide various capabilities such as location awareness that are not normally incorporated in fixed Grid resources. Nevertheless, mobile devices exhibit inferior characteristics such as poor performance, limited battery life, and unreliable communication, compared to fixed Grid resources. Therefore, the job scheduling and the load balancing are more challenging and sophisticated in mobile Grid environment. This paper presents a novel balanced scheduling algorithm in mobile Grid, taking into account the mobility and availability in scheduling. We analyzed users΄ mobility patterns to quantitatively measure the resource availability that is classified into three types: full availability, partial availability, and unavailability. We also propose a load balancing technique by classifying mobile devices into nine groups depending on availability. The experimental results show that our scheduling algorithm provides a superior performance in terms of execution times to one without considering availability and load-balancing. [ABSTRACT FROM AUTHOR]

The goal of mobile GRID is to provide the same QoS to mobile users as experienced by wired users. However, inherent unstable nature of the wireless network causes many challenges. Inherent characteristics make frequency disconnection, delay, and jitter. For the reason, we focus on the error resilience scheme for video communication over mobile GRID environments. We propose an error concealment technique to recover lost motion vectors at the H.264 decoder side. To recover the lost motion vectors, there are two simple techniques: (1) no prediction, where the lost motion vectors are set to zeros, and (2) the prediction using the average or median of spatially adjacent blocks΄ motion vectors. In this paper, we propose a Kalman filter based scheme for motion vector recovery, and experimented with two test image sequences: Mobile&Calendar and Susie. The experimental results show that our Kalman filter based motion vector recovery scheme improves at average 2 dB PSNR over conventional H.264 decoding with no error recovery. We also improve our scheme using Hilbert curve scan order for Kalman input, and we get 0.512 – 1.652 dB PSNR improvements with better subjective quality over line-by-line scan order. [ABSTRACT FROM AUTHOR]