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Semantic Web Workshop 2002 Hawaii, USA

Copyright by the authors. is utilized to make sure that the content corresponds to the a "‘Semantic Web-enabled HTTP server"’ While these tools aim into the right direction, they still both from a common fact base { , thus requiring the user desired structure. The two systems mentioned above are ment containing information about the department’s sta, Given a Semantic Web tool followed a generative aptage addressing simplicity, the generative approach provides tool would then be able to generate the actual HTML pages place at run-time, we arrive at a tool that could be seen as able to incorporate regular HTML for the unstructured part to maintain this fact base only, at least as far as structured number has to be propagated to the RDF version as well as ontology and fact management. Information is stored in a able to export their fact base to an RDF representation. tured site like this is suitable for participating in the semanTake, for example, a typical web site for a university departresearch topics, projects, and publications. A highly structhe HTML version. tic web, and it can easily be modelled using a corresponding automatically from the existing RDF information { or even RDF-version of the facts as well as a human-readable knowledge base providing ne grained access. The ontology other advantages that fall into the area of "‘added value"’: for insertion of information contained in the fact base. The have a problem: As long as one wants a machine-readable information is concerned. If the generation of pages takes While the avoidance of redundancy already is a big advandomain ontology. Yet, a change as simple as a telephone proach, the situation would be easier: Assume this tool were HTML-version, duplicate eort is required to main tain both. of the web site, and these pages could contain placeholders Looking at existing tools developed for or related to the Semantic Web, for example Protege-2000 [23] or Ontobroker [15], one notices that these are primarily designed to support language also allows to specify integrity constraints for them domains such as university departments often still use plain weight"’ database solution. (more than 10), each of which potentially contains only a use of database tables. in maintaining the tables. icantly. For a low number of instances, the internal knowlUsing Semantic Web tools, the picture may change signifsites with a simple, low-dimensional structure, such as guest Here, the reason may be that a high number of taHTML les for their w eb presentation, or make only limited cient. Associations are direcly supported, and the ontology tion tables, this results in quite a lot of normalised tables a possible UML class diagram of the database’s conceptual features and thus position it as an alternative to a "‘heavyTo broaden the possible target audience of our Semanbles would be required for modeling even simple ontologies, single set of data, does not outweigh the extra eort inheren t model. Since all n:n associations require separate associasearch topics, projects, and publications. Figure 1 shows end are quite common these days (e.g. Cold Fusion [8], PHP tic Web server, we might try to incorporate database-like [ 2 ], Enhydra [1] etc.), these solutions are mainly used for mainly because associations are not rst class members of at an appropriate level. Since Semantic Web tools usually While relational databases with HTML-generating frontedge base provided by a Semantic Web tool may be suÆrelational database systems. Revisiting the university deforms for editing the tables is avoided.

In this case, the benet for the creator, that is, the dyvery small subset of all the possible instances. namic generation of HTML or { in our case { RDF from a come with a generic user interface, the need to create HTML books or news pages (e.g. Slashdot.org). More complex partment scenario, we need at least tables for persons, re2.2 Incorporation of database features 3. THE INFORMATION LAYER 2.3 Incorporation of Content Management

Features 2.4 Openess to Alternative Schema Languages 3.1 XMI Import content for instances of the class \Member". In the temtology on top of the SWRC ontology. Also, SWRC concepts local ontology automatically [12]. However, this feature is organization can be stored in a single static RDF le, not which is determined from the page URL. which may be bloated and still not fullll all local requireand last name. If the local application requires having both plates, elements in a special namespace, denoted by the t does not match the \shared" SWRC ontology exactly. Howbloating the local ontology. like \Organization" may not be required in a local ontology name slot illustrates the advantage of this approach: SWRC covering a single organization. Information about the local the corresponding information, when building the local onwithout needing to extend a predened shared ontology, signed to t the needs of our \regular" w eb presentation, it parts available separately, it would be necessary to duplicate prex in the example, are replaced b y content queried from tance hierarchy of the SWRC ontology. be possible to generate RDF directly corresponding to the In addition to template based RDF generation, it would contains only one person name slot that is not split into rst not implemented yet. template that is used to generate SWRC-compliant RDF the Information Layer with respect to the current instance ever, using the template mechanism of our system, we are able to generate RDF pages corresponding to the SWRC ments. Instead, the domain of interest can be modelled using a lean domain specic local on tology. The SWRC person Thus, it is possible to participate in the Semantic Web Since our \local" research unit ontology was primarily deontology on the y . Figure 3 shows a simplied example 3.2 HTML Generation 3.3 SWRC and RDF Integration 3.4 Infrastructure Integration <RDF xmlns="http://www.w3.org/1999/02/22<ScientificStaff xmlns="http://www.semanticweb.org/ont xmlns:p0="http://www.w3.org/1999/02/2 <name>Stefan Haustein</name> <email>stefan.haustein@udo.edu</email> <phone>+49 231 755 2499</phone> <fax>+49 231 755 5105</fax> </ScientificStaff> </RDF>

3.5 File Upload 3.6 Installation This installation makes use of the content management feaThe Information Layer is also being used as a prototypical support, nor do not have a priority here in the future. velops multimedia teaching material for software engineering able protocols and known bugs. Changes to the fact base web presence for MuSofT, a Germany-wide project that debeen and still are are used as a basis for the MLnet teaching rent form is a database for Java-enabled small devices like Previous versions of the Information Layer system have plications, please refer to http://infolayer.org. into the system from a Web browser. To allow eÆcient reA web site that utilizes the Information Layer in its curtured information suitable for the Semantic Web. We did education. The site’s goal is to manage and distribute the using the system’s ontology capabilities. not put a focus on advanced features like full DAML+OIL ogy descibes the devices, their capabilities, vendors, availand content management features to broaden the target auavoid redundancy, others are the incorporation of database trieval of material, meta-data is provided LOM2-conforming cell phones and personal digital Here, the ontol- assistants1. learning objects contributed by the various project partners. tion of HTML as well as RDF from a common fact base to tures the system provides: Learning object can be uploaded in the Semantic Web. One of these benets is the generaare quite frequent, but do not require the duplicated eort of updating a human and a machine-readable version, which information and in various internal projects. server3 For more details about the Information Layer and its apdience. This way, we hope to improve availability of strucmakes the site very easy to maintain. 5. REFERENCES 3.7 Related Systems 4. CONCLUSION AND OUTLOOK 1http://www.kobjects.org/devicedb 2http://ltsc.ieee.org/wg12/index.html 3http://kiew.cs.uni-dortmund.de:8001/