A TAXONOMY OF PARTIALLY EXCLUDED SERVICE DESCRIPTIONS B. Al-Ani (Ph.D. Candidate, email: taha@ee.uts.edu.au) J. R. Leaney (Senior Lecturer, email: jrleaney@ee.uts.edu.au) D. B. Lowe (Senior Lecturer, email: dblowe@ee.uts.edu.au) Computer Systems Engineering, Faculty of Engineering, University of Technology, Sydney, Tel: (02) 9514 2000 Abstract: This paper presents a taxonomy of partially complete service descriptions based on the desirability of excluded information. The taxonomy is founded on the premise that services captured in natural language are incomplete because features have been totally or partially excluded. The premise of partially excluded service description and taxonomy classes are discussed and mathematically defined. Applying the suggested classification scheme will assist the requirement analyst in determining the best course of action to be taken. INTRODUCTION The problem of incomplete requirements (captured in natural language) is an existing reality for most practitioners (Luqi 1997, Siddiqi 1996). This problem may lead to assumptions about intended system behaviour (Woods, 1994, Davis, 1993). While a greater degree of completeness may be achieved using formal documentation methods (i.e. Z specification language), such an approach is not feasible when dealing with the user requirement document because requirements have not matured to the point of formal requirements specification. At the front end of the requirement formulation process there is usually a set of key documents. Although the documents in the set vary depending upon the particular development process, it sometimes consists of the needs report document, the user requirements document (URD), and the user requirements specifications document (URSD). Incomplete transfer of information from one document to another could occur during the requirement formulation process resulting in an incomplete requirement document. The URD is considered of primary importance because it is the basis of the URSD (which is usually a formal version of the URD). The main purpose of this paper is to outline a taxonomy of service descriptions that are excluded from the URD. Oncoming sections provide background information on which the taxonomy is