Approaches to use semantic web technologies in real applications.

Seiler, Sven ; Sell, Raivo

1. INTRODUCTION

System overspanning compatiblity in smart houses and building automation is still a serious problem today. Variant systems, such as light and heating control or door closure systems manufactured by different producers can not operate together. These proprietary systems are not built to be controlled by one central controlling unit, but mostly only by one special kind of proprietary software or controlling hardware. These circumstances makes it impossible to build complex systems which can interoperate without any interfaces and communicate with each other.

The W3C and Tim Berners Lee is still working on a new approach to make the internet, and therefore in further step any information machine readable (Bernes-Lee et al., 2001). This is realized in the Semantic Web initiative. The focus of this paper is to combine the Semantic Web with the field of building automation to make such systems smarter and (more) intelligent.

2. STATE-OF-ART

There are several different systems existing on the market in the areas of building automation and smart houses. The main flaw of most of them is that they are not compatible to each other and often proprietary software must be used to control such automation installations. There are several approaches and standards to simplify the interaction of different systems, like DALI, EIB, KNX or LON. But it is also possible to have really intelligent systems which can be loosely connected and communicate with each other directly, reacting on environment changes. The combining of these technologies with building automation and smart houses shall be in focus of interest. The general idea is to make building automation more compatible by the use of XML based data exchange. In addition, intelligence systems on base of a reasoner can be set up. More than just the interchange of information between automation devices would be possible. Additional data sources, like conventional databases (e.g. student personal information database) or any XML based data can be used to support decision making.

The novelty of the system prototype developed is the use of semantic web based data for the information flow in the overall system (Tanenbaum, 2003). Also a new approach is researched, which make it possible to build an interface between the conventional "soft" information from databases and general information (e.g. student and staff databases) and the automation units. This interface (the reasoner) can react directly and change the behavior of automation units by information gathered from data sources. Therefore it is possible to give access to a particular subset of students (data from student database) to a special room (automation unit) based on information (student schedules from another database). The main intention by the researchers was to figure out the possibilities to implement semantic technologies in all day applications and the changes of improvement of such applications by the use of XML based information exchange.

3. SYSTEM DESIGN

3.1 General system overview

The overall system consists of several different parts, as presented in fig. 1, which act together.

[FIGURE 1 OMITTED]

3.2 The web server with reasoner and presentation tool

The reasoner is the logical unit of the system for formulating and implementing the goals and rules. It also reasons with information gathered from other parts of the whole facility system and can react on changes of input values directly. The reasoner is also able to change the behavior of units integrated in the whole system. Therefore it is the highest stage of controlling unit. But due to some minor (possible) intelligence in the units themselves they can also react and work independently, without the interaction from the reasoner in a restricted way.

The website presentation and control tool is also present on the web server. It is the implementation of the user interface and the interface to the database. It is also a control system for displaying system status information and semantic information in XML dialects. The presentation tool is used for a user interface to the overall system with possibilities to control its behavior.

3.3 Hardware

The ATMega128 board and the communication board are for sending opening and closing events to the door. As it can also hold information about door accessing rights, it can also act independently from the server control. In the prototype only the direct control by the reasoner and the functionality as an active closure system is implemented.

The communication board (seen in fig.2.) is a development by Hochschule Bochum during Interstudy project (Interstudy, 2008). It is directly wire connected to the ATMega128 board and the server system and can be loosely connected with Bluetooth devices. The communication board plays a main role for this implementation, as information between all devices is always transmitted over this one.

[FIGURE 2 OMITTED]

3.4 Ontology

The whole system is presented and specified by the use of XML dialects, in the Resource Description Frame Work Schema (RDFS) and Web Ontology Language (OWL) (Antoniou et al., 2004). The general structure and data structure are presented here and also a taxonomy of stated data. A rather small overview of the systems description can be seen in figure 3.

[FIGURE 3 OMITTED]

3.5 Use Case

The use case presented in fig. 4 was implemented by Sven Seiler to show the possibilities of using semantic web technologies in his thesis. It is still a lucid scenario but it shows what is possible by using semantic web technologies for controlling the building infrastructure.

The reasoner, who works with external data sources like student directory, schedules, department or laboratory affiliations or any other data source will come to a conclusion and sends his decision back to the ATMega128 controller, which will act according to this information.

In the presented use case a member from the university tries to open the door by sending his UUID by Bluetooth or RFID to the communication board. The connected ATMega128 will then "ask" the reasoner for a decision, if the controller is allowed the door for the person with the ID at this special time.

4. CONCLUSION

This approach offers many interesting aspects for deepening the research. Only a few Semantic relations could be realized in the thesis. A more detailed and complex linking of semantic information would improve the beneficing of this approach and offer more complexity of the whole system. It would be possible to dim the light in an office room, when a staff member is on holidays and he forgot to disable the light, when there are existing semantic relations between the holiday calendar and the building automation system. Also a late room change can be realized, when a professor enters a different room as an exception into a computer system, even right before his course begins. The guidance system in the building could display the new room Y next to the door of room X and show the way to the new room Y, where the course would be held. And, of course--the system directly reacts on these changes. The room Y inherits the information of room X immediately. This is not applicable in known and existing systems. Furthermore the general information exchange based on XML technologies can be used in several other units in the building automation, as well as in the smart houses for home entertainment or other systems (Seiler, 2009). The limitation of the overall system is based on the occurrence of external data sources, which can be linked to the system. The coherence of the sources must be made first by manually, because existing sources are mostly not rehashed in the appropriate form. The security aspect of this system was also not discussed, yet; a good and secure implementation would be necessary to finalize the concept to a product and offers a lot of questions for further research.

[FIGURE 4 OMITTED]

5. REFERENCES

Antoniou, G. & van Harmelen, F. (2004). A Semantic Web Primer, MIT Press, ISBN 0262012103, Massachusetts

Berners-Lee, T.; Hendler, J. & Lassila, O. (2001). The Semantic Web. Scientific American Magazine

Seiler, S. (2009). Approaches to use Semantic Web Technologies in Smart Houses, Master Thesis, Tallinn University of Technology

Tanenbaum, A. S. (2003). Computernetzwerke, Pearson Stadium, ISBN 3827370469, Munich

*** (2008) http://interstudy.ttu.ee/--Project Interstudy Website, Project Webpage, Accessed on:2009-09-28