UNCORRECTED PROOF 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 Dependability issues in visual–haptic interfaces Stefano Ricciardi a , Michele Nappi a , Luca Paolino a , Monica Sebillo a , Giuliana Vitiello a,Ã , Gabriella Gigante b , Domenico Pascarella b , Lidia Travascio b , Angela Vozella b a Department of Mathematics and Computer Science, University of Salerno, 84084 Fisciano, Salerno, Italy b CIRA Centro Italiano Ricerche Aerospaziali-Capua (CE), Italy article info Keywords: Q1 ’ ’ ’ abstract Dependability of a system is commonly referred to its reliability, its availability and its maintenability (RAM), but when this concept is applied to user interfaces there is no common agreement on what aspects of user–system interaction are related to a satisfactory RAM level for the whole system. In particular, when dealing with haptic systems, interface dependability may become a crucial issue in medical and in military domains when life-critical systems are to be manipulated or where costly remote control operations are to be performed, like in industrial processes control or in aerospace/automotive engineering and manufacturing. This paper discusses the role of dependability in haptic user interfaces, aiming to the definition of a framework for the assessment of the usability and dependability properties of haptic systems and their possible correlations. The research is based on the analysis of a visual–haptic-based simulator targeted to maintenance activity training for aerospace industry which is taken as a case study. As a result, we propose a novel framework able to collect and then process relevant interaction data during the execution of haptic tasks, enabling to analyze dependability vs. usability correlations. & 2009 Published by Elsevier Ltd. 1. Introduction When working with haptic systems, two different aspects may cause difficulties. One is related to the haptic device functional requirements, the other is related to the associated user interface (user interface requirements). Haptic devices should be designed to guarantee dexterity (no motion constraints causing uneasiness in the ex- tended use), human safety and portability (robust, easy to fit and adjust and be self-contained with wireless communications) [1,2]. However, an effective use of those devices may be strongly affected by the lack of depend- ability in the user interface, which is the second important property haptic system designers should strive for. Dependability of a system is commonly referred to the ability to deliver service that can justifiably be trusted as a result of its reliability, its availability and its maintain- ability (RAM) and this concept can be further expanded by including safety (RAMS). The aforementioned properties may be probabilistically defined as follows: (1) The reliability of a device is the probability that this device will be able to perform the function it was designed to accomplish under given conditions during a time interval (t1,t2); it is written R(t1,t2). (2) The availability of a device is the probability that this device be in such a state so as to perform the function for which it was designed under given conditions and at a given time t, under the assumption that external conditions needed are assured; it is written D(t). Fig. 1 depicts these functions. Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jvlc Journal of Visual Languages and Computing ARTICLE IN PRESS YJVLC : 457 1045-926X/$ - see front matter & 2009 Published by Elsevier Ltd. doi:10.1016/j.jvlc.2009.07.001 Ã Correspondence to: Dipartimento di Matematica e Informatica, Universita ` degli Studi di Salerno, Via Ponte don Melillo, 84084 Fisciano, Salerno, Italy. Tel.: +39089963317. E-mail addresses: sricciardi@unisa.it (S. Ricciardi), mnappi@unisa.it (M. Nappi), lpaolino@unisa.it (L. Paolino), msebillo@unisa.it (M. Sebillo), gvitiello@unisa.it (G. Vitiello), vozella@cira.it (A. Vozella). Journal of Visual Languages and Computing ] (]]]]) ]]]–]]] Please cite this article as: S. Ricciardi, et al., Dependability issues in visual–haptic..., Journal of Visual Language and Computing (2009), doi:10.1016/j.jvlc.2009.07.001