document: Model-directed web transactions under constrained modalities Online transactions ( e.g. , buying a book on the Web ) typically involve a number of steps spanning several pages . Conducting such transactions under constrained interaction modalities as exemplified by small screen handhelds or interactive speech interfaces - the primary mode of communication for visually impaired individuals - is a strenuous , fatigue-inducing activity . But usually one needs to browse only a small fragment of a Web page to perform a transactional step such as a form fillout , selecting an item from a search results list , etc. . We exploit this observation to develop an automata-based process model that delivers only the `` relevant '' page fragments at each transactional step , thereby reducing information overload on such narrow interaction bandwidths . We realize this model by coupling techniques from content analysis of Web documents , automata learning and statistical classification . The process model and associated techniques have been incorporated into Guide-O , a prototype system that facilitates online transactions using speech\/keyboard interface ( Guide-O-Speech ) , or with limited-display size handhelds ( Guide-O-Mobile ) . Performance of Guide-O and its user experience are reported .
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