A mobile agent system is regarded as an attractive technology when developing distributed applications. However, mobility makes it more difficult to trace agents. It is also more complex for agents to communicate with each other in a reliable manner. Therefore, a reliable communication protocol is necessary to control and monitor mobile agents and deliver messages between them. In this paper, a new reliable communication protocol (RCP) is proposed for a multiregion mobile agent computing environment. RCP is implemented on the ODDUGI mobile agent system. Analysis and evaluation show that RCP fulfills the following design goals: reliability, asynchrony, timeliness, location dependency, scalability, and communication cost.

Desktop Grid has recently received the strong attraction for executing high throughput applications as CPU, storage and network capacities improve and become cheaper. Desktop Grid is different from Grid in many respects, but there is no general survey or taxonomy for desktop Grid. Therefore, we propose a new comprehensive taxonomy and survey of desktop Grid in order to characterize and categorize desktop Grid.

In P2P systems, the speed of searching for desired lists of sharable files is one of the most important measurement issues in evaluation of overall system performance. Although the searching schemes of existing non-structured P2P systems have been improved to enhance speed considerably, they still never reach to the level of those of the centralized and structured systems. In this paper, we propose a multi-node global directory in P2P systems, where all the lists of sharable resources of the joining peers are aggregated and divided into the chosen nodes while keeping collating sequence as a whole to make one big linked list. Thus in indexed sequential searching, the system provides us with convenience of using the command like 'dir' of MS-DOS, and in general keyword searching, which is naturally impossible for the structured P2P systems, the searching speed is even faster than those of centralized P2P systems since a small list segment is scanned at each node synchronously in parallel

A volunteer node can join and leave a volunteer computing system freely. However, existing volunteer computing systems suffer from interruptions of job execution, delays of execution time, and increases of total execution time, since they do not consider dynamic scheduling properties (i.e. volatilities), such as leave, join, and suspension. Therefore, dynamic execution properties of volunteer node should be considered in scheduling schemes, in order to design a stable and reliable volunteer computing system. This paper proposes a new scheduling scheme based on the dedication rate (DR), which reflects the dynamic properties of a volunteer. The scheduling scheme improves the completeness and reliability of execution, while also decreasing delay and total execution time. In addition, an implementation of the proposed scheduling scheme on top of Korea@Home is described, as well as performance evaluation

Fault tolerance is essential to the development of reliable mobile agent systems in order to guarantee continuous execution of mobile agents. For this purpose, previous work has proposed fault tolerant protocols for mobile agent execution based on stage construction. However, when previous protocols are applied to a multiregion mobile agent computing environment, the overhead of work such as monitoring, election, voting and agreement is increased. We propose a region-based stage construction (RBSC) protocol for fault tolerant execution of mobile agents in a multiregion mobile agent computing environment. The RBSC protocol uses new concepts of quasiparticipant and substage in order to put together some places located in different regions within a stage in the same region. Therefore, the RBSC protocol decreases the overhead of stage works. Consequently, the RBSC protocol decreases the total execution time of mobile agents.

Location management and message delivery protocol is fundamental to the further development of mobile agent systems in a multiregion mobile agent computing environment in order to control mobile agents and guarantee message delivery between them. However, previous works have some problems when they are applied to a multiregion mobile agent computing environment. First, the cost of location management and message delivery is increased relatively. Second, a following problem arises. Finally, cloned mobile agents and parent & child mobile agents don't get dealt with respect to location management and message delivery. We present a HB (home-blackboard) protocol which is a new location management and message delivery protocol for mobile agents in a multiregion mobile agent computing environment. We have implemented the HB protocol. The HB protocol decreases the cost of location management and message delivery and solves the following problem with low communication cost. In addition, the HB protocol deals with the location management and message delivery of cloned and parent & child mobile agents, so that it guarantees message delivery of these mobile agents.

Fault tolerance is essential to the further development of desktop grid computing system in order to guarantee continuous and reliable execution of tasks in spite of failures. In a desktop grid computing environment, volunteers are often susceptible to volunteer autonomy failures such as volatility failure and interference failure in the middle of execution of tasks because a desktop grid computing maximally respects autonomy of volunteers. The failures result in an independent livelock problem (i.e. the delay and blocking of the entire execution of a job). Therefore, the failures should be considered in a scheduling mechanism. In This work, in order to tolerate volunteer autonomy failures, we propose a new fault tolerant scheduling mechanism. First, we specify a volunteer autonomy failures and an independent livelock problem. Then, we propose a volunteer availability which reflects the degree of volunteer autonomy failures. Finally, we propose a fault tolerant scheduling mechanism based on volunteer availability (which is called VAFTSM).