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<Paper uid="W06-1301">
  <Title>Adaptive Help for Speech Dialogue Systems Based on Learning and Forgetting of Speech Commands</Title>
  <Section position="7" start_page="6" end_page="7" type="concl">
    <SectionTitle>
5 Summary and Future Work
</SectionTitle>
    <Paragraph position="0"> In this paper we presented studies dealing with learning and forgetting of speech commands in an in-car environment. In terms of learning, we compared the power law of learning and the exponential law of learning as models that are used to describe learning curves. We conducted tests under driving conditions and showed that learning in this case follows the power law of learning. This implies that learning is most effective in the beginning and requires more effort the more it tends towards an expert level.</Paragraph>
    <Paragraph position="1"> Concerning forgetting we compared four possible mathematical functions: a power function, an exponential function, a logarithmic function and a square root function. Our retention tests showed that the forgetting curve was described most adequately by the exponential function. Within the observed time span of 50 days about 75% of the initial amount of speech commands have been forgotten. null The test results have been transferred into an algorithm specifying the driver's knowledge of commands within the SDS. Based on the learning experiments we are able to deduce a threshold that defines the minimal number of trials that are needed to learn a speech command. The forgetting experiments allow us to draw conclusions on how long this specific knowledge will be remebered. With this information, we developed an algorithm for an adaptive options list. It provides help on unfamiliar speech commands.</Paragraph>
    <Paragraph position="2"> Future work focuses on usability tests of the prototype system, e.g. using the PARADISE evaluation framework to evaluate the general usabil- null ity of the system (Walker et al., 1997). One main question that arises in the context of an adaptive help system is if the adaption will be judged useful on the one hand and be accepted by the user on the other hand. Depending on user behaviour the help system could shift its contents very fast, which may cause some irritation. The test results will show whether people get irritated and whether the general approach for the options lists appears to be useful.</Paragraph>
  </Section>
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