SecurityAutomated telephony Usability Empirical study Dialogue design a b s t r a c t This paper describes an experiment to investigate user perceptions of the usability and security of single-factor and two-factor authentication methods in automated telephone banking. In a controlled experiment with 62 banking customers a knowledge-based, singlefactor authentication procedure, based on those commonly used in the financial services industry, was compared with a two-factor approach where in addition to the knowledgebased step, a one-time passcode was generated using a hardware security token. Results were gathered on the usability and perceived security of the two methods described, together with call completion rates and call durations for the two methods. Significant differences were found between the two methods, with the two-factor version being perceived as offering higher levels of security than the single-factor authentication version; however, this gain was offset by significantly lower perceptions of usability, and lower ratings for convenience and ease of use for the two-factor version. In addition, the twofactor authentication version took longer for participants to complete. This research provides valuable empirical evidence of the trade-off between security and usability in automated systems. ª

This paper describes the evaluation of an educational game designed to give learners of foreign languages the opportunity to practice their spoken language skills. Within the speech interactive Computer-Assisted Language Learning (CALL) program, scenarios are presented in which learners interact with virtual characters in the target language using speech recognition technology. Two types of interactive scenarios with virtual characters are presented as part of the game: the one-to-one scenarios which take the form of practice question and answer scenarios where the learner interacts with one virtual character and the interactive scenario which is an immersive contextualised scenario where the learner interacts with two or more virtual characters within the scene to complete a (task-based) communicative goal. The study presented here compares learners' subjective attitudes towards the different scenarios. In addition, the study investigates the performance of the speech recognition component in this game. Forty-eight students of English as a Foreign Language (EFL) took part in the evaluation. Results indicate that learners' subjective ratings for the contextualised interactive scenario are higher than for the one-to-one, practice scenarios. In addition, recognition performance was better for these interactive scenarios.

a b s t r a c tThis paper describes an experiment to investigate the usability of voiceprints for customer authentication in automated telephone banking. The usability of voiceprint authentication using digits (random strings and telephone numbers) and sentences (branded and unbranded) are compared in a controlled experiment with 204 telephone banking customers. Results indicate high levels of usability and customer acceptance for voiceprint authentication in telephone banking. Customers find voiceprint authentication based on digits more usable than that based on sentences, and a majority of participants would prefer to use digits.

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