Exploring Usability Needs by Human-Computer Interaction Patterns

Covering quality aspects such as usability through the software development life cycle is challenging. These “-ilities” are generally difficult to grasp and usually lack an appropriate quantifiability, which would ease their systematic consideration. We propose a pattern-based development method supporting the identification of usability requirements and their proper specification. By taking usability principles from Human-Computer Interaction (HCI) design patterns and incorporate them into patterns for software analysis (problem frames), we obtain a new kind of patterns applicable for requirements engineering: HCIFrames. They are used for exploring usability needs of a given problem situation. 1 Motivation and Related Work Patterns for developing software have become popular for quite some time. They support reuse of development knowledge, which has proven of value, and can assist developers to build software efficiently. A common approach is using design patterns, which represent best practice solutions for recurrent, but also varying design problems. They were originally introduced in architecture by Alexander et al. [1] and first transferred to the software domain by Beck and Cunningham [2]. Gamma et al. [7] developed a pattern catalog for Software Engineering (SE). Recently, design patterns have encountered high interest in Human-Computer Interaction (HCI), where various pattern collections for different purposes exist, e.g. web design [14], user interfaces [13], groupware applications [11], navigational design [10], or collections of general HCI design patterns [3]. From the SE point of view there are two drawbacks for HCI design patterns that we take into account. Firstly, many HCI design patterns are still merely represented by graphics such as screenshots and a corresponding text passage containing their natural-language description, even though approaches for formalizing them exist [6]. This meets the philosophy to provide patterns understandable by laymen, but constrains their methodical deployment in the software development life cycle. Secondly, there are many synonym patterns in diverse collections, even if the pattern authors use different names for their design patterns and describe them in different ways. From the HCI point of view common SE approaches neglect to address quality aspects or so-called non-functional software properties [4]. Primarily, they concentrate on describing the functionality of a program, although quality aspects, e.g. usability should be built systematically into software from the beginning. As different views of the term usability exist [15], our understanding of usability refers to ISO 9241-110:2006 [9].