Resource Information Management of Spatial Information Grid Deke Guo, Honghui Chen, Xueshan Luo Department of Management Science and Engineering, National University of Defence Technology, Changsha, 410073, P.R. China
[email protected]
Abstract. Spatial Information Grid (SIG) is an infrastructure and framework which enable us to congregate and share large-scale, heterogeneous, distributed spatial resources across dynamic “virtual organizations”, to organize and manage spatial resources systematically. In order to enable the users and soft agents to locate, select, employ and integrate spatial resources semiautomatically in SIG, we propose the idea of resource information management, and describe it from the aspects of framework, resource information description and resource information registry. Furthermore we proposed the design and implementation solution of resource information registry.
1 Introduction Spatial data is the data that can be associated with location on Earth. It also is the dominant form of data in terms of data volume, and has been widely used in many fields of social and economic activities, ranging from mines exploitation to mobile application. China has accumulated large-scale, heterogeneous spatial resources which include established and establishing fundamental spatial database, spatial data processing and application software, spatial facility and instrument, etc. But these spatial resources were distributed over related departments for long, and this has caused lots of obstacle when other users want to share, integrate spatial resource across departments and regions dynamically. This difficult problem can be characterized as grid problem defined as “Flexible, secure, coordinated resource sharing among dynamic collections of individuals, institutions, and resources” [1]. We propose Spatial Information Grid (SIG) as an effective solution of this grid problem based on the latest grid theory and technology, this solutions involved adoption of a service-oriented model and attention to metadata. In the following, we first introduce the philosophy of SIG in section 2. In section 3, we discuss the resource information management solution from the aspects of framework, resource information description and resource information registry in details. Section 4 is the conclusion and our future work.*
*
Supported by National High Technology Research and Development Program of China
2 Spatial Information Grid SIG is defined as an infrastructure and framework which enables us to share distributed, large-scale, and heterogeneous spatial resources across dynamic virtual organizations cooperatively, organizes and deals with them systematically. It aims to make any kinds of users acquire spatial information on any kinds of spatial resources, especially the metadata about spatial resources, and possesses the capability of service-on-demand. The sharing that we are concerned with is not primarily file exchange but rather direct access to computers, software, data, and other resources. As the increasing spread of sharing architecture and technologies for spatial resources, especially Web services and OGSA (Open Grid Services Architecture) [2], all kinds of wide-area distributed, large-scale, and heterogeneous Web-accessible spatial data/program /device/sensor could be encapsulated diverse spatial web service and grid service. Although there will be enough spatial services in the future, they are deployed on discrete information isolates. In order to enable users and agents can locate, select, employ and integrate spatial service across those discrete information isolates effectively and efficiently, SIG should provide appropriate and efficient mechanism to describe, publish, manage, and discover metadata information of spatial resources and services shared, namely resource information management.
3
Framework of Resource Information Management
To make use of a spatial web service, user needs interpretable and standard description of the service, and the means by which it is accessed. An important goal for spatial resources information management, then, is to establish a framework within which these descriptions are made and share. The framework builds upon the spatial resource grid, and provides technical support for resources information description, publication, discovery and employ. Furthermore, it exposes a unified starting point for resources information publication, organization and sharing, that is the resources information registry. The framework has the characteristic of open and extensible. The fundamental framework designed based on web service protocol stacks just supports the Human user to discover, interpret, select and invocate spatial resource freely, it is difficult for software agent to do so. The extensible framework focus on the semantic markup for spatial resources, Thus Human user and software agent should be able to discover, interpret, select and invoke spatial resource. Figure 1 shows the extensible framework that will be discussed in detail in the following chapter. 3.1 Resource Information Description There are two kinds of major languages which we can select to describe spatial web service, which are Web services Description Language and DAML-S [3]. WSDL provides a communication level description of the messages and protocols used by a
web service, while DAML-S provides application level description above WSDL. The fundamental framework just adopts WSDL, but the extensible framework employs not only WSDL but also DAML-S. WSDL doesn’t support semantic description of Web services. DAML-S describes the semantic markup information of Web services from aspects of Profile, Process Model, and Grounding. Profile and Process Model are considered to be abstract specifications, in the sense that they don’t specify the details of particular message formats, protocols, and network addresses by which a Web service is instantiated. The role of the grounding is to provide these more concrete details.
Resources information registry
Users
discover
DAML-S Profile, UDDI Spatial resource description information
WSDL DAML-S Grounding
Other description language
Spatial resource invocate
Spatial web service
use
Spatial fundamental Resource
Fig. 1. The Extensible Framework of Resource Information Management
3.2 Resource Information Registry As mentioned above, the fundamental and extensible framework requires a unified registry which supports the publication, organization and discovery of the description information about spatial web service both in WSDL and DAML-S format. There are many kinds of different registry methods and standards. For example: 1) Metadata registries defined by ISO standard 11179; 2) Registries for software components and developments; 3) Universal Description, Discovery and Integration (UDDI) registries; 4) Electronic Business XML (ebXML) registries; 5) SQL database catalogs. Among these methods and standards, UDDI [4] is the most suitable for spatial web service, which is completely compatible with WSDL. But UDDI does not support semantic descriptions of services. Thus, depending on the functionality offered by UDDI specification, although agents can search the UDDI registry and retrieve service descriptions, a human needs to be involved in the loop to make sense of the descriptions, and to program the access interface. In order to satisfy the need of the extensible framework, we must combine UDDI specification and DAML-S specification. Academe already pays more attention to this problem and has lots of achievement, such as [5].
3.2.1 Resources Information Publication and Discovery Resources information registry aims to facilitate the publication and discovery of potential business partners, services and their groundings. This may or may not be done automatically. When this discovery occurs, programmers affiliated with the business partners program their own systems to interact with the services discovered. DAML-S enables more flexible discovery by allowing searches to take place on almost any attribute of the Service-Profile. Resources information registry must offer a Web service compliant Inquiry, Publication, Security, and Ownership API sets, please refer [4] for more details. The Subscription and Value Set API sets are optional for resources information registry. But these API sets just base keywords, don’t contain domain semantic information except for some taxonomies. Although it is possible to publish and discover DAML-S profile of web service by tModel, this way still is immature and impracticable. 3.3.2 Implementation of Resource Information Registry We combined the B/S and RPC model to realize the design and implementation of resource information registry. We employ Jsp as the representation technology, Java and Beans as the realization technologies of application logic, JDBC and RDBMS as the database technology in the framework of B/S. Furthermore, Simple Object Access Protocol (SOAP) is selected to realize the RPC model. Users can send the request soap message encapsulated by all kinds of SOAP toolkits to the object servlet which parses the soap message and activates related Beans to execute application logic. Then users get, parse and use the response soap message encapsulated by the servlet.
4 Conclusions In this paper, we have presented the philosophy of SIG, and analyzed the resource information management problem of SIG from the aspects of framework, resource information description and resource information registry. Furthermore we proposed the design solution of resource information registry. In the future work, we will pay more attention to import the domain semantic in the resource information registry.
References 1. Ian Foster, Carl Kesselman, Steven Tuecke. The Anatomy of the Grid-Enabling Scalable Virtual Organizations. Intl J. Supercomputer Applications, 2001 2. Ian Foster, Carl Kesselman, Jeffrey M. Nick4 et al. The Physiology of the Grid-An Open Grid Services Architecture for Distributed Systems Integration. Draft paper, 2002 3. Ankolenkar, A., Burstein, M., Hobbs, J.R. DAML-S: Web Service Description for the Semantic Web. The First International Semantic Web Conference (ISWC), June, 2002 4. Barbara McKee, Dave Ehnebuske. UDDI 2.0 API Specification. http://www.ud di.org/pubs/ ProgrammersAPI-V2.00-Open 20010608.pdf , June 2001 5. Paolucci, M., Kawamura, T., Payne, T.R. and Sycara, K. Importing the Semantic Web in UDDI. Web Services, E-Business and Semantic Web Workshop, 2002
