A formal approach supporting the comparative predictive assessment of the interruption-tolerance of interactive systems

Abstract

This paper presents an approach for investigating in a predictive way potential disruptive effects of interruptions on task performance in a multitasking environment. The approach combines previous work in the field of interruption analysis, formal description techniques for interactive systems and stochastic processes to support performance analysis of user activities constrained by the occurrence of interruptions. The approach uses formal description techniques to provide a precise description of user tasks, and both system and interruptions behavior. The detailed mechanism by which systems and interruptions behave is first described using a Petri nets-based formal description technique called Interactive Cooperative Objects (ICO). The use of a formal modeling technique for the description of these three components makes it possible to compare and analyze different interaction techniques. In particular, it allows us to determine which of the system states are most affected by the occurrence of interruptions. Once composed together, models describing the system, user tasks and interruptions behavior are transformed into PEPA models (i.e. Performance Evaluation Process Algebra) that are amenable to performance analysis using the PRISM model checker. The approach is exemplified by a simple example that models two interaction techniques for manipulating icons in a desktop environment.

State of the Art on Formal Methods for Interactive Systems

“…set of states represented in intention in Petri nets while represented in extension in an automata). (Palanque et al 2009) Formal verification involves techniques that are strongly rooted in mathematics. Defects in models can be detected by formal verification.…”

Student Response to Teaching of Memory Cues and Resumption Strategies in Computer Science Classes

“…He then experimented with sensors to evaluate a person's personal and social interruptability and achieved a 98.1% recognition score for social interruptability. Palanque et al [25] analyzed interruptions using model-based analytical techniques that could be used in designing interruption-tolerant systems. To demonstrate, the authors used a case study to compare two interaction techniques, Speak and Drop and Drag and Drop, and found the latter was more resistant to interruptions.…”

A Model-Based Approach for Supporting Offline Interaction with Web Sites Resilient to Interruptions

“…Notwithstanding, there are some situations where the interruption of present task can be predicted -in particular when users decided to get interrupted -, so that the systems should provide an alternative representation of the interrupted tasks. Only a few works in the literature have addressed the description of interruptions in system specifications [14]. It is interesting to notice that despite the fact that modelbased approaches [15] are prominent in the field of Web engineering, as far as we could investigate there is no clear proposal for using Model-Driven Approaches for building Web sites resilient to interruptions.…”

“…Formally speaking an interruption can be defined as a (intentional or unexpected) switch between two tasks; when an interruption occurs, users are forced to do something else (the secondary task) until the primary task can be resumed [19].It has also been shown that interruptions will ultimately affect users' ability to complete tasks but the disruptive effect varies according to the type of interruption (e.g. system alarms and notification, denial of service, loss of connectivi-ty…) [14]. Thus, there is no universal solution for dealing with interruptions.…”

“…Nonetheless, an interruption is not a fate. Indeed, previous works [6,14,18] have shown that it is possible to design interactive applications resilient to interruptions. The term resilient is often used to name systems that are able to recover from failures, but in the present context it is used to qualify applications that can prevent from the occurrence of interruptions, help users to resume from interrupted tasks, and/or ensure a minimum level of service for performing a task in spite of the interruption [14].…”