Suihui Zhu

GDSA: A Grid-Based Distributed Simulation Architecture

This paper focuses on architecture suitable for large-scale simulation system. Based on the scenario of large-scale Internet simulation, the grid technology is introduced and a new architecture, GDSA is proposed. GDSA, a full grid-based architecture mainly focuses on four pending problems in distributed system: scalability, communications, management mechanism and QoS insurance computing environment. The advantages of grid in scalability and uniform communication will be used to improve systems scalability and communication method. Management system will be built according to meta-service mechanism. Contractual computing mechanism (CCM), a special mechanism added in GDSA, will provide QoS insurance for users. Three-layer QoS model, which is the core of CCM, will take charge of QoS problems in different levels. At the end, a prototype is designed and the experiment results based on this platform show that GDSA is a promising system to overcome the pending problems in distributed simulation

Dynamic Service Composition Based on Peer-to-Peer Network

To address the problem of service composition in SOA, this paper presents a novel mechanism to abstract a complex composite service as a peer-to-peer network. Thus, the problem of service composition is converted into a problem of peer-to-peer network construction. An extended state machine model is developed to extract the network model from a service. Based on this model, a service composition algorithm is introduced in detail to show the service composition process. A Pastry based service composition is given to show how to build complex service using peer-to-peer network. A MetaService based prototype reveals that the peer-to-peer based service composition mechanism is efficient, reliable, flexible and reusable

QoS Enhancement for PDES Grid Based on Time Series Prediction

The combination of parallel/distributed discrete event simulation (PDES) and Grid technology is a new trend in simulation. QoS is important yet difficult in this process. With the special features of Gird architecture and PDES input, such as periodical and predictable inputs, we could enhance QoS with a PDES-specific prediction. A Grid-based framework is presented that is designed to help predict the performance of PDES. Based on this framework, a prediction algorithm using time series theory is presented in the context of large scale Grid simulations. Experiments are executed in the context of GridSim, which shows methods discussed before to help to improve QoS level.

A Pipeline Virtual Service Pre-Scheduling Pattern and its Application in Astronomy Data Processing

Based on Open Grid Services Architecture (OGSA), the concept and the formal model of Pipeline Virtual Service (PVS) are proposed and presented in this paper. PVS is used to model a special type of grid workflow composed of a group of services that can be executed as a pipeline. A PVS Pre-Scheduling Pattern is described in detail, which can overlap the execution time of a PVS with the time of generating and optimizing the scheduling solution pool. The Pattern includes two independent components, the solution generating component (GenFunc) and the solution execution component (ExeFunc). GenFunc can take advantage of the powerful computing potential of grid environment to find the optimal or a near optimal scheduling solution, while ExeFunc can select a suitable scheduling solution and put a PVS into running as soon as possible. Two corresponding algorithms, SODGen and SODExe, are also developed. The analytic and simulation results show that the PVS Pre-Scheduling Pattern can not only balance the scheduling cost and scheduling precision, save the scheduling time greatly, but also reduce the execution time through selecting the optimized solution. A prototype is designed and implemented for a large scale astronomy data processing center. The early engineering evaluation experiments show that the PVS Pre-Scheduling Pattern is feasible, efficient, and flexible in real astronomy data processing.Based on Open Grid Services Architecture (OGSA), the concept and the formal model of Pipeline Virtual Service (PVS) are proposed and presented in this paper. PVS is used to model a special type of grid workflow composed of a group of services that can be executed as a pipeline. A PVS Pre-Scheduling Pattern is described in detail, which can overlap the execution time of a PVS with the time of generating and optimizing the scheduling solution pool. The Pattern includes two independent components, the solution generating component (GenFunc) and the solution execution component (ExeFunc). GenFunc can take advantage of the powerful computing potential of grid environment to find the optimal or a near optimal scheduling solution, while ExeFunc can select a suitable scheduling solution and put a PVS into running as soon as possible. Two corresponding algorithms, SODGen and SODExe, are also developed. The analytic and simulation results show that the PVS Pre-Scheduling Pattern can not only balance the scheduling cost and scheduling precision, save the scheduling time greatly, but also reduce the execution time through selecting the optimized solution. A prototype is designed and implemented for a large scale astronomy data processing center. The early engineering evaluation experiments show that the PVS Pre-Scheduling Pattern is feasible, efficient, and flexible in real astronomy data processing.

A Service Level QoS Mechanism and Algorithm for Data Distribution and Backup in an Grid Based Astronomy Data Management System

Based on the research of SLA, SNAP, MetaService and contractual computing service, a service level QoS mechanism and algorithm for astronomy data distribution and backup in grid environment is proposed. A weight based comparison method for different data services provided by data servers is described first. The method can choose suitable data servers under the requirements of consumers. Based on the weight based comparison method, a data distribution algorithm is designed and this algorithm can obtain an optimized data allocating solution with a time complexity of O(x lg x + nxy) . In a practical example of data distribution and backup, the balancing mechanism is explained between two factors: the performance and the cost. The mechanism and the algorithm have been implemented in an astronomy data management prototype system. Compared to non- QoS guarantee scenario, a set of experiments with different weights of performance and cost have been tested and the results show that the QoS guarantee method can satisfy consumers requirement effectively.

A market-oriented model for grid service management

Grid service management and trading is a complex undertaking as services are geographically distributed, heterogeneous and large-scale, owned by different organizations with their local policies. Each service provider needs flexible relationships between them, and each consumer joins Grid with the intention of getting its purchase requirements satisfied. To allow Grid to reduce the cost of e-business trading, to deal faster and to open up more new opportunities, a market-oriented architecture called GTM (Grid Trading Model) is proposed in order to establish a real-life Grid which provides a business mechanism for organizing users and services efficiently based on market economic rationale. GTM derives from an inherent similarity between typical networks and classical economic market structures based on Virtual Organization (VO) concept and the small-world theory. An emulated environment is presented to illustrate the models economic feature, performance and cheap service trading cost.

A Grid QoS Provision Solution for PGAS based on MetaService and CCM

This paper mainly focuses on solution to QoS provision in power grid analysis system (PGAS) which is an improvement for the electric power information system. The solution consists of two parts. The first part is the grid QoS provision model for PGAS based on metaservices and CCM. The model is proposed based on requirement of data-intensive QoS guaranteed grid systems. The second part is an adaptive scheduling algorithm which handles two types of tasks (with/without QoS guarantee tasks) in PGAS. Simulations of two types of tasks based on GridSim show the results of our solution can meet various QoS requirements of users in PGAS and the scheduling algorithm take good effect.

Optimizing Service Data Transmission in an OGSA Based Grid System

The problem of providing suitable data transmission mechanism among services is critical in an Open Grid Services Architecture (OGSA) based grid system. Four typical data transmission methods between two services are provided first. Then for one complex data transmission patterns among multiple services, the corresponding data transmission scheduling mechanism is discussed in detail. Based on the steps of one data transmission path between two services, a data transmission performance prediction model is described. Together with some implementation and environment dependent parameters, the model can provide different performance prediction functions for different data transmission methods. At the same time, a set of comparison experiments have been designed and tested in a grid environment built up with Globus Toolkit 3. The comparison results show that the theoretical data transmission performance is very close to the experimental performance. At the end of the paper, a grid data transmission optimizing MetaService is designed to select suitable transmission mechanism in a grid environment dynamically. The MetaService can adapt to different scenarios, and improve the data transmission performance.

Automatically building service evaluation metadata in a grid environment

This paper presents a mechanism that automatically build evaluation metadata for grid services by using the information from the execution of different applications. A new MetaService AMDBS, automatic metadata building service, is designed to support this mechanism. The typical feature of this mechanism is that it can get not only the absolute evaluation information, but also the relative global ranking result through the collaboration of different AMDBSs. Web service group testing is used as an example of a grid application to accelerate the process of evaluation metadata building. Simulation experiment results show that the HP (heavy-powerful) algorithm which is designed based on the dynamic evaluation metadata can improve the application performance significantly, compared with the RR (round-robin) algorithm which does not use the evaluation metadata. The effect of using evaluation metadata in different task and resource conditions is also demonstrated by experiment results