Apr. 1, 2008 Second Life is more than an on-line game for ETH Zurich. It is a handy three-dimensional tool used for resolving real issues. ETH Zurich Computer Science students recently used it to analyze and solve the everyday frustrations involved in borrowing a book from a library.
The project to tackle the problems that lending libraries face was carried out within the framework of the Information Systems Laboratory course taught by Professor Nesime Tatbul at the Computer Science Department (D-INFK), The study of information systems is a core area of computer science. It has evolved from the more established study of database management. Research into information systems now includes pervasive computing: the convergence of largely wireless technologies and the Internet. This may well signal a shift away from personal computing and into pools of shared information, available to anyone from anywhere at any time.
Professor Tatbul’s lab group used the ETH Zurich island in Second Life to visualize an automated library that uses Radio Frequency IDentification (RFID) technology. The virtual environment created in Second Life was the typical library setting: a check-out counter, a help desk, detection gates against theft and a self check-in area. In reality, books were tagged with RFID labels and so were the ID cards of the library users. RFID readers were placed at the shelves, at a check-out counter, as well as at the library exit. There was, true to Second Life custom, the ever-hip female avatar, providing library presence. All that remained was to invite ETH Zurich’s first virtual bookworm.
The research group used five event detection queries to illustrate their system. For example, a book was checked in and checked out, a humdrum exercise that could lead to more than a bit of trouble if inaccuracies were recorded. And all libraries have trouble holding onto reference books that are restricted to internal use. Then there is the tendency to check out more than the allowed number of books on one subject, which is almost as great a problem as outright theft. All of these events reflect real life. Nevertheless, the researchers introduced some distinctively Second Life characteristics too, especially the way a book flew through space to be stuck on a wall after having been checked out properly.
The system architecture of the Smart RFLib System is three-tiered. Its most important layer is data acquisition, the layer that interacts with the RFID tags on the books and on people via library cards. Electronic readers and antennas capture the data that itself is cleaned and compressed based on a time period or an event. The second tier – query processing – analyzes the collected information, detects important events of interest (theft, for example), and triggers the appropriate action or alert in response. This in turn updates the database, which then activates the third layer, visualization, which enables the viewer to see the results in three dimensions.
It is essential that the data be clean, in other words, non-repetitive and always relevant. Although there are two data cleaning choices at the data acquisition layer, the adaptive method was chosen over the fixed-window alternative since it accommodates the uncertainty of data volume in a more flexible way.
Sizing up the facts
And size matters. RFID tag readers harvest huge amounts of data. To compress this deluge into fewer tuples (sequenced lists of objects), the project group developed two methods: regular responses to be sent by book-tags or data that are captured only when a tag acquires new information.
Of course, solving one problem often creates another. In this case, the new challenge was getting the query processing layer to talk to Second Life. There was a third difficulty as well: how to get Second Life to receive and process events from the real world.
The normal client-server architecture for Second Life detects changes in the status or position of objects from the inside. Each object has its own script written in LSL, the Second Life programming language. Sophisticated though it is, Second Life is not able to capture all the information that one would like to keep track of concerning library books, people or policies. Therefore, the Informations Systems Lab students had to design an additional web interface to complement their Second Life visualizer. This interface enabled virtual visitors to make their own queries about books, check their current status as book borrowers and keep tabs on the system itself, all in real time.
The SmartRFLib project team were able to use their five events to illustrate how well their approach worked. As well, they enjoyed being vigilant Second Life librarians: at the same time that one person was following the correct procedure in checking out a book, a maverick visitor tried to steal one. The alarm sounded. That test and others showed that the research team had achieved their goals; policy could be maintained and applied in their 3D library.
Working with RFID was not easy, but the ETH Zurich Information Systems Lab project demonstrated that SmartRFLib could also be adapted to other RFID-based data management applications. Supply chain management, for example.
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