Methodology for rapid prototyping and testing of Speech Recognition user interfaces in Telefonica Moviles Espana

摘要

Telefonica Moviles Espana (TME) is Spain's largest mobile telecommunications operator in number of customers. TME is continuously providing new services to its customers and a main objective is to ensure their usability. One of the key services deployed during 2002 has been the Portal de Voz (Voice Portal). This service provides hierarchical navigation on prerecorded or synthetic speech contents like news, weather forecasts, horoscope, stocks news, and also complex queries, as films shown in a specific theatre, all obtained by a complex information retrieval service that can be managed by both speech recognition and more traditional DTMF commands. The product brief placed great emphasis on the usability of the system, and thus planned for a corporate Style Guide for dialogues and navigation procedures. This Style Guide was made available to designers and developers from the beginning of the project, and iteratively refined from early tests of the prototypes. The user tests were based on a methodology that combined usage scenarios, several types of users, and different use contexts, by means of experimental design procedures. However, the difficulty in producing realistic working prototypes in early phases suggested the need to have a software tool that could emulate limited sets of the system functions in selected contexts, to allow quick testing by using a software simulation rather than actual prototypes. This software tool is called SIS-PRUEBA and is built on top of Microsoft Visio~(TM), integrating proprietary software tools to manage the simulation processes, the user tests and data capture, and the generation of documents from the trials. The software tool can also simulate data services, by using a mobile terminal on-screen emulator. In short, SIS PRUEBA: 1. Integrates realistic usage scenarios within a standard software design tool. Designers can easily integrate user responses and input together with more usual functional parameters. 2. Makes possible the on-line query of the style guide developed prior to the project. 3. Simulates realistic user navigation processes by scanning through the forms represented in flowcharts. This way it allows detecting and storing critical points and errors by means of rapid tests on the flowcharts. 4. Allows the quick testing of variations of important system properties: time-outs, delays, interruptibility of speech sequences, number of active grammars, error probabilities associated to speech recognitions, etc. 5. Generates and manages user test cases by applying experimental design procedures to the combinations of scenarios, contexts and type of users. This software tool has made possible a quick deployment in TME of a design methodology firmly based on customer needs, and focused from the beginning on the usability.