263 EXPLORING USER INTERFACE DESIGN PATTERNS Costin Pribeanu ICI Bucharest, Bucharest, Romania Email: pribeanu@acm.org Jean Vanderdonckt Universite Catholique de Louvain, Louvain-la-Neuve, Belgium Email: vanderdonckt@isys.ucl.ac.be Abstract User interface design patterns could increase the usability while reducing the software development effort. In this paper we explore design patterns for the derivation of the presentation from task and domain models. Key words: user interface design, design patterns, HCI 1 Introduction Little budgets and low usability awareness in organizations has always been an obstacle in promoting the effective use of user and task models. On another hand, the widespread use of software engineering methodology paying little attention to usability issues but providing with effective integration between subsequent design stages creates a strong appetite for productivity in the development process. Therefore designers rarely consent to pay an extra effort by using task models as driving specifications towards usable designs. This paper aims at investigating how user interface design patterns could increase the usability while reducing the software development effort. The basic idea of our approach is to identify typical interaction structures in the task and domain models and to elaborate on a pattern language that captures the essential mappings between the various models that are used in the development process. A special emphasis is put on the relation between the task and presentation models. 2 Usability patterns and design patterns Pattern languages are representations that focus on the interaction between physical form and social behaviour and express design solutions in an understandable and generalizable form [2]. The original model for patterns was the work of Christopher Alexander and his colleagues [1] who applied pattern languages in architecture and urban design. The emphasis was put on the characteristics of the physical form of the built environment, which can afford certain social behaviour.