Service-oriented grid architecture and middleware technologies for collaborative e-learning

Grid middleware provides a way to integrate computational and storage resouces for supporting large-scale applications that span across multiple domains. Implicitly, Grid middlware eliminates the interoperability obstacle between different resources. However, with the emerging of a bunch of Grid middlewares, to provide interoperability between Grid middlewares themselves is an important challenge in production Grid infrasturtures. Web Service technologies (specifically, Simple Object Access Protocol) have been adopted in most of the Grid middlewares as the XML messaging protocol for the interoperability in the application layer. For other layers, standard protocols are also adopted for interoperability, e.g., HTTP is utilized as service transport protocol. On the other hand, security is a key issue that needs to be taken into account on each layer, for instance, WS-Security (Web Service Security) is considered as an augment on SOAP protocol for applying security to Web Services; GSI (Globus Security Infrastructure) is considered as an protocol for applying security to transport layer. We present the design consideration and implementation about how to provide flexible support for security protocols in the Advanced Resource Connector(ARC) Grid middleware, and this way clients or/and services developed in ARC middleware can easily interoperate with service/client developed in other middlewares, such as gLite and Globus Toolkit. Also, a flexible authorization framework is presented that can secure the Grid services with configurable authorization modules, as well as a variety of authorization policies.

Significant progress has been made in the design and development of Grid middleware which, in its present form, is founded on Web services technologies. However, we argue that present‐day Grid middleware is severely limited in supporting projected next‐generation applications which will involve pervasive and heterogeneous networked infrastructures, and advanced services such as collaborative distributed visualization. In this paper we discuss a new Grid middleware framework that features (i) support for advanced network services based on the novel concept of pluggable overlay networks, (ii) an architectural framework for constructing bespoke Grid middleware platforms in terms of ‘middleware domains’ such as extensible interaction types and resource discovery. We believe that such features will become increasingly essential with the emergence of next‐generation e‐Science applications. Copyright © 2005 John Wiley & Sons, Ltd.

To be effectively adopted in different application domains, next‐generation Grids need to address different issues such as: an increasing complexity and distribution of applications; different goals, skills and habits of Grid users; availability of different programming and deployment models; heterogeneous capabilities and performances of access networks and devices. Moreover, scientific and commercial applications, as well as Grid middleware, will increasingly produce an overwhelming quantity of application and usage data. Although the ongoing convergence between Grids, Web Services, and the Semantic Web constitutes a milestone towards a service‐oriented Grid architecture, which has the potential to face important issues such as application programming and business modelling, many other issues need research and development efforts. The great availability of data and information at the different layers of Grids, the maturity of data exploration techniques able to extract and synthesize knowledge, such as data mining, text summarization, semantic modelling, and knowledge management, and the demand for intelligent services in different phases of application life cycle are the driving forces towards novel knowledge‐based Grid services. Guided by those considerations, the paper first introduces main requirements of next‐generation Grids and then describes some representative knowledge‐based Grid services for both applications support and system management. Simple cases study showing how such services could be employed are discussed. Copyright © 2005 John Wiley & Sons, Ltd.

The research activity accounted for in this Ph.D thesis belongs to the general field of electrical and electronic measurement. The attention is focused on the implementation of GRID services for performance assessing of digital wireless communication systems. The original contribution consists in the development of two original measurement methods, the former allows measuring the modulation quality of systems compliant with IEEE 802.16d-2004 standard by means of any hardware characterized by a enough sample rate and input band width, and the latter carries out reliability and efficiently the in-service measurements also in presence of in-channel interferences. The high computational burden experienced during the wide experimental phase by proposed methods has encouraged their implementation according to GRID Service paradigm. Respect to the classic Web Service, GRID Service provides the possibility of both sharing the proposed methods among researches and technicians who work on the same topics, and processing some proposed methods stages in parallel way on several calculus nodes, thus reducing the whole processing time. Differently from the normal GRID Service, the developed GRID Services involve the measurement instrumentation, such digital acquisition systems and waveform generator, other than the calculus nodes. Suitable strategies for discovering, accessing, setting the measurement instruments have to be provided for. To this aim, new GRID architecture has been proposed, which virtualizes the measurement instruments into new components, namely instrumentation devices, and makes use of classic mechanisms already presented in GRID architecture, such as PBS scheduler, for dealing with the instruments discovery issue. To take advantage from the proposed GRID Services, a proper web portal is also implemented. An intense experimental phase is executed for assessing the methods and GRID Services performance by applying emulated and real communication signals. Measurement results are analyzed and compared to those achievable through the application of existing methods and/or instrument available on the market. Particular attention is also made to the processing time measurement of GRID Service with respect to a sequential implementation, in order to evidence the gains provided by a parallel implementation.

This paper reports on the design, implementation and performance evaluation of a suite of GridRPC programming middleware called Ninf-G Version 2 (Ninf-G2). Ninf-G2 is a reference implementation of the GridRPC API, a proposed GGF standard. Ninf-G2 has been designed so that it provides 1) high performance in a large-scale computational Grid, 2) the rich functionalities which are required to adapt to compensate for the heterogeneity and unreliability of a Grid environment, and 3) an API which supports easy development and execution of Grid applications. Ninf-G2 is implemented to work with basic Grid services, such as GSI, GRAM, and MDS in the Globus Toolkit version 2. The performance of Ninf-G2 was evaluated using a weather forecasting system which was developed using Ninf-G2. The experimental results indicate that high performance can be attained even in relatively fine-grained task-parallel applications on hundreds of processors in a Grid environment.

In the research area of grid computing and workflow technology, workflow products based on Web-service technology can work as grid services in grid architecture. A new algorithm of scheduling grid resource with workflow engine is discussed in this paper. The QoS, executing time of process, cost and workload of grid resources are the key factors in grid resources scheduling. Dynamic feed back mechanism and executing time estimation are applied in this algorithm, which can keep the grid resources in a good balance and advance the whole performance of the grid application with workflow service.

Grid computing is becoming a research focus in distributed and parallel systems. The idea of the grid service being a kernel of the whole grid architecture is accepted by the researchers. The grid service has the characteristics of high scalability and dynamic. By analyzing the resource management in heterogeneous environment and agent-based hierarchy model, this paper presents an agent-based distributed model on grid service advertisement and discovery. It can’t only satisfy the scalability and dynamic of grid service, but may also reduce the system overhead comparing to central management of service advertisement

The open grid services infrastructure (OGSI) defines a distributed system framework by integrating grid and Web services technologies to facilitate the sharing of various resources, which result in grid service. Grid service inherits the features from Web service, aiming at enabling interoperability among heterogeneous grid application. However, in the open grid services architecture (OGSA), grid services are isolated, it is difficult building a grid service management framework which can work across organizations. Based on BPEL4WS, this paper proposes an agent-oriented grid service modeling framework to address the difficulties in developing grid applications based on grid services.

As the complexity of application system for enterprises, an important challenge is to dynamically schedule and integrate the heterogeneous and distributed services or activities to work cooperatively and efficiently. An effective technology to resolve the problem is grid service. A grid service built on both grid computing and web services technologies is an extended Web service. An application system for enterprises is a grid service composition that consists of a collection of grid services related by data and control flow. Therefore, there is a need for modeling and analyzing techniques and tools for reliable and effective grid service composition. The Petri net based method is an idea approach. in this paper, we use a colored dynamic timed Petri net (CDTPN) to model the grid service composition. The definition of CDTPN for grid service and an algorithm to construct a composite service are proposed. We give a definition of reachable service graph and an algorithm for constructing the reachable service graph of CDTPN. Finally, we discuss the correctness and effectiveness of the grid service composition by analyzing the reachable service graph.

Interactive Problem Solving Environments (PSEs) offer an integrated approach for constructing and running complex systems, such as distributed simulation systems. New distributed infrastructures, like the Grid, support the access to a large variety of core services and resources that can be used by interactive PSEs in a secure environment.We are experimenting with Grid access for interactive PSEs built on top of the High Level Architecture (HLA), a middleware for interactive simulations. Our current approach is such that once a PSE simulation has been executed in the framework, mechanisms from both HLA and Grid middleware are used to broker resources, for job submission services, performance monitoring services, and security services for efficient and transparent execution.We are experimenting with the Web-based Open Grid Services Architecture (OGSA) for HLA RTI Federate registration and discovery, as well as for data transmission. We have found that Grid Services give the possibility to allow for dynamic modification capabilities of HLA Federates, though the dynamic discovery of Federates and the use of Service Data (metadata) for service introspection is not trivial. Also, we have found that opening many data transmission channels between HLA Federates to one destination affects the number of connections you can make with other destinations.KeywordsPSEinteractiveGridOGSAHLA

The aim of this thesis is to design and implement a new Grid Resource Management methodology, where non-massive resources owners would be able to share their resources and integrate human collaboration across multiple domains regardless of network technology, operative platform or administrative domain.<br/>This thesis proposes a distributed and heuristic policy-based resource management architecture for large-scale Grids. The resource management architecture proposed herein is composed of four main building blocs: services management, resource discovery and monitoring, resource scheduling and jobs allocation and activation. The Grid Services Management (GSM) and Jobs Allocation and Activation (JAA) are supported by means of a Policy-based Grid Resource Management Architecture (PbGRMA). This architecture is able to identify service needs arising from diverse sources during the deployment and management of Grid Services, such as requirements demanded by customers, applications and network conditions. Afterwards, the PbGRMA merges these requirements into deployment policies for the corresponding Grid Services. The Grid Resource Discovery and Monitoring (GRDM) is supported by the introduction of the SNMP-based Balanced Load Monitoring Agents for Resource Scheduling (SBLOMARS), in which network and computational resources are monitored by distributed agents. This allows for a flexible, heterogeneous and scalable monitoring system. The Grid Resource Scheduling (GRS) is based on the Balanced Load Multi-Constrained Resource Scheduler (BLOMERS). This heuristic scheduler represents an alternate way of solving the inherent NP-hard problem for resource scheduling in large-scale distributed networks by means of the implementation of a Genetic Algorithm.<br/>Finally, based on the outcome of both the GRDM and GRS, the PbGRMA allocates the corresponding Grid Services by means of its interfaces with Globus ToolKit Middleware and Unix-based CLI commands along of any large-scale Grid Infrastructure. <br/>The synergy obtained by these components allows Grid administrators to exploit the available resources with predetermined levels of Quality of Service (QoS), reducing computational costs and makespan in resource scheduling while ensuring that the resource load is balanced throughout the Grid. The makespan of a schedule is the time required for all jobs to be processed when no one job could be interrupted during its execution and each node can perform at most one operation at any time.<br/>This new approach has been successfully tested in a real large-scale scenario such as Grid5000. The results presented along this Thesis show that our general solution is a reliable, flexible and scalable architecture to deploy and manage Grid Services in large-scale Grid Infrastructures. Moreover, the substitution of the heuristic algorithm approach used into the Grid Resource Scheduling (GRS) phase by other non-heuristics selection algorithms could make our solution useful in smaller Grid Infrastructures.

This paper describes the design and implementation of CampusWare, a lightweight grid middleware for the compute-intensive applications in campus environment. Though there are many grid middlewares available, they are unnecessarily complex for use in the campus environment where the main applications are compute-intensive, and the main requirements are the convenience and efficiency in clusters management and job submissions. To deal with the problem, CampusWare proposes a “fast job” concept and provides a two-layer middleware architecture as well as a three-layer user account hierarchy. Compared with the existing grid middlewares, its deployment, configuration and usage are all simplified, which makes it easy-to-use, efficient and portable.

Grid technology is widely used in recent years, it has solved the real sharing of resources, make each node of unified command and use of resources, the information grid is on the basis of computational grid, using data mining. Information fusion and search engine technology and building are advantageous for the collection and sharing of grid resources. The goal to create a build on OS and Web is based on the new generation of Internet information platform. In this platform, the distribution of the information processing is the collaboration and intelligent. Focus crawler sets according to the target subject. In the form of intelligent collection topics come from the Web page, and then adopt the method of machine learning. The information retrieval on the collected information intelligent need process and analyze. Finally, the effective retrieval way is to meet the demand of the user's information retrieval.

Grid Middleware and Services

Grid technology has received wide acceptance in fields ranging from industry to academia. Its capability to integrate heterogeneous and distributed computing resources to provide transparent access has been leveraged in different areas of computing needs including healthcare provisioning. The global effort focuses on exploiting the grid infrastructure opportunities in the enhancement of health related activities. This paper reviewed few of the existing healthgrids in the context of applying existing grid infrastructures and middleware in providing specific medical services. The focus is on the services provided using grid services and infrastructures, the middleware forming the bases of interoperability between the services as well as service client specific applications. The contributions of this paper are to highlight and identify open problems, challenges within the healthgrid that can impede the goal of pervasiveness healthcare provisioning.