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C.-H. Chi and K.-Y. Lam (Eds.): AWCC 2004, LNCS 3309, pp. 369373, 2004. Springer-Verlag Berlin Heidelberg 2004 Dynamically Reconfiguring Sitemaps Using RDF* Huijae Lee and Sang Bong Yoo School of Computer Science, Inha University, Incheon, Korea Fax: 82-32-874-1435 cyberelfislabs.inha.ac.kr, syooinha.ac.kr Abstract. This paper presents extracting, storing, and applying the metadata and ontology of product data. In this paper, the design and tooling information included in STEP-NC files is focused as an example. By analyzing the relation-ship among the product data, the RDFS schema is designed first. Based on the schema, metadata is extracted and stored in RDF files. As an application of the stored metadata, we can reconfigure the sitemap of product data repositories. The users can select the view that he or she is interested in (e.g., the views from products, tools, persons, or a current location). The sitemaps also can be con-structed from current location dynamically. With such various and dynamic views of product data repository, the users can access the specific data more ef-fectively. 1 Introduction As the Internet prevails all over the world, requirements to handle the data on the Web have been increased rapidly. The Semantic Web, which was initiated by W3C, is an effort to capture more meaning of the data on the Web 1, 2, 4, 6, 8, 9. RDF (Resource Description Framework) and RDFS (RDF Schema) are the primary tools to serialize the metadata from the Web, which enable software agents or human can understand the contents. XML was introduced to enhance the syntax and semantics of Web data over HTML by using meaningful tags with structured schemata. For exam-ple, by using XML we can represent the same person as an employee in one place or as a customer in another place. However, XML has a limited capability to capture the interrelationship among objects. RDF and RDFS have been introduced in order to complement XML with rich semantics of the relationship among objects. One issue in realizing the virtual enterprise is how to support the exchange of product information among application systems or personnel involved in the virtual activities. This is important to obtain the agility for improving the competitiveness of firms. There are two types of data that the enterprises need to properly manage, i.e., business data (e.g., accounting and personnel data) and product data (e.g., CAD and CAM data). Many modern enterprises have enough experience in dealing with busi-ness data, but it is not the case for product data, in particular when the product data need to be exchanged throughout the whole product life cycle with systems dealing with the business data. Product data used to be managed only by the design and pro-duction activities. However, for the virtual enterprises the product data need to be used in later stages of product life cycle (e.g., Web catalog and service manual) 7. Differently from business data, product data have complex semantics and thus are not properly exchanged by different application programs 7. Even though some * This research was supported by Inha University. 370 Huijae Lee and Sang Bong Yoo neutral formats of product data have been developed by standard organizations, trans-lating them among various application programs still needs the comprehensive under-standing of the complex semantics. Recently, it is widely recognized that capturing more knowledge is the next step to overcome the current difficulties on sharing prod-uct data 5. This paper presents extracting, storing, and applying the metadata and ontology of product data. In this paper, the design and tooling information included in STEP-NC files is focused as an example. By analyzing the relationship among the product data, the RDFS schema is designed first. Based on the schema, metadata is extracted and stored in XML files. As an application of the stored ontology and metadata, we can reconfigure the sitemap of product data repositories. The users can select the view that he or she is interested in (e.g., the views from products, tools, persons, or a cur-rent location). With such various views of a product data repository, the users can access the specific data more effectively. 2 Reconfigurable Sitemaps Sitemaps usually have hierarchical structures. However, as you can see the RDF schema, the structure of the schema for product data is a general graph that includes cycles. For drawing this graph as a sitemap, we have several choices to select a node to be the root node. According to the selection of the root node, different hierarchical structures result as in Fig. 1. There are 3 different structures in Fig. 1; each of them starts from nodes Model, Tool, and Person, respectively. Because different users may have different views of interests, it would be very useful to enable the users to select a particular node as the root in a sitemap. The algorithm for reconfiguring sitemaps from RDF schema is basically same as the level search of graphs. The algorithm for reconfiguring sitemaps is as follows. Because the algorithm traverses each node only once, the complexity of the algorithm is O(n). Algorithm Reconfiguring Sitemaps Input: RDF Schema, Starting node Output: Hierarchical Sitemap Procedure Initialize a queue and a sitemap Insert the Starting node into the queue and the sitemap While (queue is not empty) Dequeue a node from the queue Mark the node as visited and add it into the sitemap For each properties of the node If (it is not marked as visited) Add it to the sitemap Enqueue it into the queue 3 Prototype of Product Data Repository A prototype of product data repository has been implemented and the reconfigurable sitemaps have been applied with example data. The overall architecture of the proto-Dynamically Reconfiguring Sitemaps Using RDF 371 type is depicted in Fig. 2. Because the product data are usually specified in design files, we analyze standard design files (i.e., STEP files) and extract metadata from them. Extracted metadata are stored in RDF files and analyzed for reconfiguring sitemaps. The users can use Web browsers to navigate the product data repository. (a) Structure from node Model. (b) Structure from node Tool. (c) Structure from node Person. Fig. 1. Different structures of RDF model from various nodes Fig. 2. Architecture of the prototype of a product data repository In order to handle STEP and RDF files the following libraries are used in the pro-totype: a) ST-Developer: A commercial tool from Steptools Inc. It analyzes STEP files and extracts metadata from them. b) IsaViz: RDF generator and viewer from W3C. It verifies and tests RDF files. 372 Huijae Lee and Sang Bong Yoo c) libgnurdf: RDF tool from gnu. It supports C programming for generating RDF files and adding data to them. d) RAPRDF-API: It generates and extracting data from RDF files with php pro-gramming. e) Others: php 4.2.3 and VisualStudio Fig. 3 depicts a screen capture of the prototype. After the user logged in, he or she can select the type of sitemaps (e.g., model view, tool view, and person view). The screen captured in Fig. 3 is an example of model view. When the user click the Ima-geName (i.e., 20021313oh.jpg in Fig. 3), the image file is on the browser as in Fig. 4. In Fig. 4, we can see a link named “From Here”. When this link is clicked, the site-map from the current location is displayed as in Fig. 4. This is an example of dynamic sitemap that draws a hierarchical structure of data from the current location. For dy-namic sitemap the same algorithm can be applied as for reconfigurable sitemaps. Fig. 3. An example of sitemap from the node Model Fig. 4. An example of dynamic sitemap 4 Conclusion As an application of metadata and ontology represented in RDF and RDFS, respec-tively, reconfigurable and dynamic sitemaps are presented in this paper. In virtual enterprise environments, there are mainly two types of data, i.e., business data and Dynamically Reconfiguring Sitemaps Using RDF 373 engineering data. As for the business data we have enough experience to organize and handle them effectively. However, because the structures of engineering data are usually general graphs including cycles, representing their structure hierarchically is not trivial. According to the interests of the users different views of sitemaps are more helpful. A simple algorithm has been presented to provide different sitemaps to the users for product data repositories. The same algorithm can be applied for generating a dynamic sitemap that draws the structure form the current location dynamically. The reconfigurable and dynamic sitemaps enable the user can access the information more effectively that he or she is looking for. A prototype of product data repository that supports the reconfigurable and dynamic sitemaps has been implemented and pre-sented. The contribution of this paper can be summarized as follows. Models the metadata and ontology in RDF and RDFS, respectively, for data re-positories. Presents an algorithm that generates reconfigurable and dynamic sitemaps for data repositories. Implements and presents a prototype of data repositories that supports the recon-figurable and dynamic sitemaps. Prospected application areas of the proposed system are almost all data repositories with complicated structures and relationship among stored data. Most engineering data repositories (e.g., CAD, CAM, e-manufacturing systems, GIS, LBS, real-time systems, monitoring systems, and tracking systems) have these characteristics. In order to be more powerful, it needs to be extended with various development tools. Novice users may have difficulties to model the metadata and ontology in RDF and RDFS, respectively. Some user-friendly designed GUI tools could make the system more effective. References 1. Tim Berners-Lee, J. Hendler, and Ora Lassila, “The Semantic Web A new form of Web content that is meaningful to computers will unleash a revolution of new possibilities,” Sci-entific American, May 20