Abstract:

Abstract:Recently the research about heterogeneous database access and integration is booming in grid technology and related applications.UDMGrid(university digital museum grid)is devoted to the integration and sharing of resources from 12 university digital museums with grid technology,and it is necessary for UDMGrid to investigate the mechanism and method for heterogeneous specimen-database access and integration.In this paper,an effective schema-reusable method on database access and integration in UDMGrid(UDMGrid-DAI)is presented.It includes a schema-reusable virtual database to define the global uniform or heterogeneous database resources,and to describe the concepts and their relations of one or one sort of scientific domain through virtual tables and virtual columns.It also includes the ways of database registering and query mapping to the virtual databases based on the above virtual database mechanism.Furthermore,This UDMGrid-DAI provides a consistent interface to the virtual databases through the registry processing and the virtual database services.Finally,the experimental results demonstrate the work of this paper,and show that this schema-reusable mechanism of virtual database is correct and useful on database access and integration,especially in UDMGrid.

Abstract:RAM(random access memory)Grid is a new grid system aiming at memory resources sharing in wide-area network;it can improve the performance of memory intensive or IO intensive applications when lack of physical memory.Reducing or hiding the network overhead can improve the performance of RAM Grid,which lies on the overhead of network communication.In this paper,through the analysis of RAM Grid,a “push” based prefetching mechanism is proposed for it.The corresponding prefetching algorithm,which comes from the sequential pattern mining method in data mining area,is also raised.The prefetching algorithm is evaluated and proved by trace driven simulation.

Abstract:In grid environment, when every participating node tries to maximize its own utility, the overall utility of the collaboration drops. In the worst case scenario, grid resources are easily depleted due to selfish users taking free rides without offering any sharing resource. Certain resource management scheme has to be implemented on grid systems to ensure them working properly and to achieve better scalability. In this paper, the relationship of resources incentive and allocation in the grid is discussed. In grid computing, the evaluation of shared resource is the key to allocate and manage them. To address the issue, the price strategy of sellers and an adaptive trust-incentive compatible resource allocation mechanism ATIM (adaptive trust-incentive compatible resource allocation) are presented to ensure the balance of supply and demand, promote the users to share valuable resource, and maximize resource utility. Intending for a secure collaborative environment, the framework considers the factors of trust and economy to ensure the steady development of grid resource market. This approach is also evaluated by comprehensive experiments in CROWN (China research and development environment over wider-area network).

Abstract:Web services management and organizing technologies based on syntax level can not meet the need of getting relevant information,responding to diversity service request and reusing Web services in information grid.In this paper,a Web service dynamic integrating and constructing(WS-DIC)strategy based on ontology for information grid is proposed.By the ontology and its reasoning capability,WS-DIC can reuse existing Web services to generate an optimized integrating or constructing paths set to meet the need of request diversity and information relevancy.By the abstraction and formalized model of WS-DIC,the regulation and arithmetic of dynamic integration and reconstruction is discussed.Experimenters indicate that WS-DIC can effectively get the optimized integrating or constructing path and get more advantage then full-text search and SQL query.

Abstract:As resource management becomes a hot research in Grid Computing area,current research forces on solving heterogeneity of grid environment,but the research on enhancing the efficiency of resource management on condition of delivering seamless QoS(quality of service)is not very abundant.In addition,current research about Grid QoS forces on importing related fruit on QoS from multimedia network to support Grid QoS.For that,a hierarchical structure of gird QoS is proposed in this paper.QoS parameters are newly classified into five categories and they can be measured at VO(virtual organization)layer.Then by making use of SNAP(service negotiation and acquisition protocol),the analysis on QoS parameter mapping and converting based on the hierarchical structure model is also addressed.At last,the research on Grid QoS is applied to scheduling heuristics to improve on Min-Min algorithm.The result of the simulation shows that QoS-based resource management can effectively improve grid resource utilization and service ask for success rate in dynamic service-oriented grid.

Abstract:Focusing on the problem of task scheduling under large-scale,heterogeneous and dynamic environments in grid computing,a heuristic algorithm based on fuzzy clustering is presented.Many previous scheduling algorithms need to search and compare every processing cell in the target system in order to choose a suitable one for a task.Though those methods can get an approving Make-span,undoubtedly,it would increase the entire runtime.A group of features,which describe the synthetic performance of processing cells in the target system,are defined in this paper.With these defined features,the target system,also called processing cell network,is pretreated by fuzzy clustering method in order to realize the reasonable clustering of processor network.In the scheduling stage,the cluster with better synthetic performance will be chosen first.There is no need to search every processing cell in the target system at every scheduling step.Therefore,it largely reduces the cost on choosing which processing cell to execute the current task.The design of the ready task's priority considers not only the influence that comes from the executing of nodes on critical path,but also the influence induced by heterogeneous resource,on which the task will be scheduled.In the last part,the algorithm's performance is analyzed and compared with other algorithms,and the test results show that the bigger the target system is,the better performance the algorithm shows.

Abstract:In this paper, a novel k-Nearest Neighbor (k-NN) query over the Chinese calligraphic character databases based on Data Grid is proposed. First when user in the query node submits a query character and k, the character filtering algorithm is performed using the hybrid distance metric (HDM) index. Then the candidate characters are transferred to the executing nodes in a package mode. Furthermore, the refinement process of the candidate characters is conducted in parallelism to get the answer set. Finally, the answer set is transferred to the query node. If the number of answer set is less than k, then the query procedure is re-performed by increasing the query radius until the k nearest neighbor characters are obtained. The analysis and experimental results show that the performance of the algorithm is good in minimizing the response time by decreasing network transfer cost and increasing parallelism of I/O and CPU.

Abstract:With the richness of common database resources, distributed users in wide areas hope to transparently access and use these data resources on demand. DS_Grid (database grid) is an SOA (service-oriented architecture) based database grid system for data sharing in multiple application domains. DS_Grid adopts a P2P (peer-to-peer) Multi-Chord (MultiChord) architecture to realize the distributed storage, query processing and dynamic data integration of data resources. According to the text similarity, the data resources are registered to the corresponding domains to realize rapidly discovering data resources. The domain ontology knowledge and reasoning rules are used to support the semantics based intelligent query. A multi-root and multi-peer maintenance based data resources replica management mechanism is applied to improve the reliability of the system. A keyword filter based distributed data integration strategy is adopted to reduce the communication cost. A distributed clustering technique is used to summarize the huge data information. The experiments demonstrate the feasibility and effectiveness of the key techniques of DS_Grid.

Abstract:Grid scheduling which aims at improving resource utilization and grid application performance is a key concern in grid. Currently, much research can be found about grid scheduling and some algorithms on it were proposed. However, since grid resources are autonomic, distributed and their status change over time, those scheduling algorithms did not fit for the cases well. In this paper, a cache based feedback grid scheduling (CBFS) approach is presented to capture the dynamics and impact of simultaneously co-allocated tasks in a grid. In this approach, grid scheduler utilizes recent resource performance data, such as recent task submitting time and execution time of task which are kept in cache and a feedback approach to engineer load balancing across multiple grid resources. After comparing this dynamic grid scheduling approach with previous research, it is found that CBFS is more generous than other scheduling approaches. Experimental results demonstrate that this approach diminishes latency and contributes to the overall grid load balancing, which significantly improves resource utilization and response time of tasks.

Abstract:How to dynamically select, bind and invoke Web service that can best meet the requirements of service consumer is an ongoing research topic in Web services community. In this paper, a QoS-Guaranteed and distributed mechanism of Web service discovery is proposed, which supports Web service discovery with QoS constraints and enhances the QoS of service discovery system. First, a novel three-dimensional QoS model of Web service is introduced, and a Web service-selecting algorithm is proposed based on the novel model. Second, the implementation model of UDDI (universal description, discovery, and integration) specification is improved by integrating the service-selecting algorithm based on QoS constraints. Third, an unstructured peer-to-peer network of UDDI with an informed routing protocol based on Bloom Filters is proposed, and an extended Kautz graph is used as the logical topology of this network. The experimental results show that the new mechanism for Web service discovery possesses higher recall rate, query response rate, and better load balance. Furthermore, the results for QoS of the selected Web service can satisfy the requirements of service consumers.

Abstract:Grid software test is an important approach to assure the quality of grid services, so it has been the highlight of the grid technology. As an open architecture, SOA (service oriented architecture) supplies the effective method and means for grid technology. In this paper, the key technology for service oriented grid software test is discussed. The grid software testing environment is designed, and emphasis is laid on the grid services test, the grid performance test, and the test management of grid software.

Abstract:QoS allows for the selection and execution of Grid workflow to better fulfill customer’s expections. Introducing of QoS can provide means for schedule of component services and make the execution of workflow satisfy the requirements of users better. The estimate algorithms of QoS and QoS-awared workflow schedule are two basic problems of workflow QoS management. In this paper, the QoS parameters of grid workflow are discussed, the corresponding QoS estimate algorithms are presented based on a Grid workflow model, and the problem of QoS-awared gird workflow schedule is proposed. Some QoS-awared schedule algorithms are discussed and a solution based on genetic algorithms is proposed.

Abstract:Task scheduling is a fundamental issue in achieving high performance in grid computing systems.However,it is a big challenge for efficient scheduling algorithm design and implementation.In this paper,the problem of scheduling independent tasks on tree-based grid computing platforms,where resources have different speeds of computation and communication,is discussed.In contrast to minimizing the total execution time,which is NP-hard in most formulations,an integer linear programming model for this problem is presented.Using the model,the optimal scheduling scheme that determines the optimal number of tasks assigned to each computing node is obtained.With the optimal scheduling scheme,two demand-driven and dynamic heuristic algorithms for task allocation are proposed:OPCHATA(optimization-based priority-computation heuristic algorithm for task allocation)and OPBHATA(optimization-based priority-bandwidth heuristic algorithm for task allocation).The experimental results show that the proposed algorithms for the scheduling problem obtain better performance than other algorithms.

Abstract:Task scheduling is a fundamental issue in achieving high performance in grid computing systems. However, it is a big challenge for efficient scheduling algorithm design and implementation. In this paper, the problem of scheduling independent tasks on tree-based grid computing platforms, where resources have different speeds of computation and communication, is discussed. In contrast to minimizing the total execution time, which is NP-hard in most formulations, an integer linear programming model for this problem is presented. Using the model, the optimal scheduling scheme that determines the optimal number of tasks assigned to each computing node is obtained. With the optimal scheduling scheme, two demand-driven and dynamic heuristic algorithms for task allocation are proposed: OPCHATA (optimization-based priority-computation heuristic algorithm for task allocation) and OPBHATA(optimization-based priority-bandwidth heuristic algorithm for task allocation). The experimental results show that the proposed algorithms for the scheduling problem obtain better performance than other algorithms.

Abstract:Failure detector is one of the fundamental building blocks to build reliable grid environments. There are large numbers of distributed applications with different QoS of failure detection in grids. Thus, in order to keep its efficiency and scalability in grid environments, a failure detector should not only provide QoS of accurate failure detection for applications, but also avoid redundant loads of designing multiple detectors for different QoS. Therefore, a new failure detector GA-FD (adaptive failure detector for grid) is presented, which adopts heartbeat detection strategy based on PULL mode. GA-FD can provide QoS of failure detection for multi-applications according to quantitative QoS metrics , and does not need any hypothesis about message behavior ),,(UMLMRUDTTTand clock synchronization. In addition, it proves that GA-FD implements a failure detector that belongs to ◇P in the partially synchronous model, and the experimental results are given in the end.

Abstract:In grid environment, resource load prediction is one of the most important problems in resource allocation optimization. But load status is difficult to estimate accurately due to the dynamic nature and heterogeneity of grid resource. In response to this issue, a resource allocation strategy that uses sequential game method to predict resource load for time optimization in a proportional resource sharing environment is proposed. The problem of multiple users bidding to compete for a common computational resource is formulated as a multi-player dynamic game. Through finding the Nash equilibrium solution of the multi-player dynamic game, resource load is predicted. Using this load information, a set of user optimal bids is produced to partition resource capacity according to proportional sharing mechanism. The experiments are performed based on the GridSim toolkits and the results show that the proposed strategy could generate reasonable user bids, reduce resource processing time, hence overcome the deficiency of Bredin’s strategy, which is not concerned with resource load variation. The conclusion indicates that employing sequential game method for load prediction is feasible in grid resource allocation and adapts better to the dynamic nature of heterogeneous resource in grid environment.