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Start of funding 01.01.2004

Porous InP: A New Host Material for Biosensing Applications

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This project originated from our ongoing work where porous InP formed by oscillating anodization in HCl is being explored for sensor applications. For the first time, it has been demonstrated that adsorption of small organic molecules (sucrose) induced changes in the refractive index of porous InP. It has been found that the excellent sensitivity combined with the high stability make porous InP an ideal potential host for biosensing applications. During this work we joined the expertise of the Bavarian and Californian groups to fabricate a new optical biosensor based on chemically modified thin films of porous InP. The detection of reversible binding of IgG to a protein A-modified surface will be investigated. Molecular binding will be detected through a shift in wavelength of Fabry-Perot fringes. We will also study and compare the sensitivity as well as the stability of such a system with a porous Si-based biosensor.

Final report:
The last decade has seen a general trend in Human-Computer Interaction to emulate aspects of human-human dialogue. Computers are ever less viewed as tools and ever more as partners or assistants to whom tasks may be delegated. The objective of the APA (Affective Pedagogical Agents) project is the development of a new generation of synthetic pedagogical agents that are able to interact with the user in a socially desirable manner. This includes the expression of emotions and attitudes via mimics, gestures and speech as well as the exhibition of politeness and empathy. Such agents will be able to promote learner motivation, engagement, and self-confidence, and will help prevent and overcome negative learner affective states such as frustration and fear of failure.

We used the politeness theory of Brown and Levinson as a starting point for modelling motivational tactics. Politeness theory provides a general framework for analyzing dialog in social situations, and in particular the ways in which speakers mitigate face threats. When human tutors interact with learners they constantly risk threatening the learner’s face, by showing disapproval or taking control away from the learner. They can also enhance learner face by showing approval and respect for the learner’s choices. This in turn can have an impact on the learner’s attitude and motivation. Prof. Johnson and colleagues have developed a model for characterizing tutorial dialog moves in terms of the amount of face threat redress they exhibit, and implemented it in a tutorial tactic generator that can vary the manner in which a tutorial dialog move is realized depending upon the degree of attention paid to the learner’s face and motivational state.

An interesting aspect of Brown and Levinson’s theory is that it applies to all languages and cultures. Every language has a similar set of methods for mitigating face threat; however, not all cultures ascribe equal importance to each type of face threat. Using politeness theory as a framework, it is possible to create tutorial tactics in multiple languages and compare them to assess their impact in different cultures. Within the APA project, we performed such a comparison. German subjects evaluated the degree of face threat mitigation implied by a range of tutorial tactics for a pedagogical agent. These ratings were compared against similar ratings by American subjects of pedagogical agent tactics in English.

Our studies have demonstrated that politeness theory applies equally to tutorial dialog tactics in English and in German, applied by pedagogical agents, as evaluated by university students in The United States and Germany. Politeness ratings are remarkably similar between the two languages and cultures. The “Du”/”Sie” distinction, which can be an important indicator of social standing in German society, does not have a significant influence on perceived politeness. There are some slight differences in judgments of politeness in individual cases, in part because direct translations are not always possible and the best equivalent translations sometimes connote a somewhat different degree of politeness. Nevertheless, the degree of correlations between American and German ratings is quite high. Obviously, the eight categories of commands retrieved from the US corpus are common in German tutorial dialogues as well. It would appear that tutorial tactics falling into these classes can be translated fairly freely between the German and American educational contexts, without much concern for differences in language, culture, or educational setting.

These results are further evidence for the contention that developers of intelligent tutors should take into account the possibility that learners will relate to the tutors as if they were social actors. They have implications for efforts to adapt pedagogical agents for other languages and cultures, to create multilingual pedagogical agents, and provided important guidelines for modelling of the behaviour of computer-based agents at USC/ISI and at Augsburg University.

During a one-month stay of Prof. André at USC/ISI, we studied the function of head movements of gestures occurring in tutorial dialogues. Based on this work, we examined cross-cultural effects of agent gestures with the European Network of Excellence Humaine in cooperation with two institutes in France (IUT de Montreuil and LIMSI-CNRS).

The results of the study were presented at AIED 2005 (International Conference in Artificial Intelligence and Education) in Amsterdam in Juli 2005 [Johnson et al. 2005]. By means of the Bacatec fundings, we financed a stay of several days by Prof. Johnson at Augsburg University in March 2004 as well as a one-month stay of Prof. André at USC/ISI in March 2005. In addition, we had five additional meetings (not financed by Bacatec) in conjunction with workshops and conferences in Kloster Irsee/Bavaria in June 2004, Marina del Rey/USA in October 2004, in Augsburg in March 2005, in Lisboa in April 2005 and in Amsterdam in July 2005.

References:
Lewis Johnson, Richard Mayer, Elisabeth André, and Matthias Rehm. Cross-Cultural Evaluation of Politeness in Tactics for Pedagogical Agents. In Proc. of the 12th International Conference on Artificial Intelligence in Education (AIED), 2005.