9126 at Work

SPACE-UFO

Introduction

The European SPACE-UFO project (Software Product Advanced Certification and Evaluation - User Focus) will provide an enhanced user-oriented method for general IT product quality requirements specification, which can be used as the "Quality Target" for both IT product evaluation processes and IT product development processes. The "Quality Target" is like a contract between the people who express the needs and define the requirements and the people who perform and produce the software product. This "contract" must be described in unambiguous language, in a formalized form which is widely recognized: the ISO 9126 standard [9126-91]. Practice shows that it is difficult to establish a relationship between a user need and its translation into a quality characteristics and therefore also an evaluation result.

The ESPRIT project SPACE-UFO will also define operational methods, evaluation instruments and training material to support rapid and effective adoption of the SPACE-method by the IT industry. Detailed experiments will validate this set. Nine European partners are involved in this project.

SPACE-UFO Methodology

Warning: the reference model presented in this chapter is SPACE-UFO copyright. These results are not definitive.

As a basis for the SPACE-UFO methodology a reference model has been defined. The concept of the SPACE-UFO reference model is displayed in the figure below. The picture consists of four levels:

the main objective level
the high level
the conceptual level
the instrumental and technical level.

This diagram is called the SPACE-UFO reference model. Processes are drawn as squares with rounded corners and real entities are drawn as simple squares.

Fig. 1: The SPACE-UFO reference model

The main objective level

The main objective of the SPACE-UFO project is to develop a methodology that is useful:

to specify the quality requirements to be set for a software product,
to assess the quality of that software product,

as seen from the user/customer perspective. It describes methods, techniques, tools and the way to apply these (guidelines). The scope of the methodology extends (see the conceptual level) from the description of business processes, user needs (or expectations) until and including the quality specification and the evaluation plan.

The high level

Business processes to be supported by the software product and user needs (or expectations) to be fulfilled require a certain software quality objective. This quality objective is expressed by one or several (software) quality characteristics. These characteristics have to meet certain requirements that are set, so as to ensure that the user needs are fulfilled. The quality characteristics can be met by the more technical characteristics of the software itself.

For instance, the business process "production to order" requires easy adaptation of programs, the computer infrastructure and the database. This implies that the aspect of maintenance is important and that certain requirements have to be set with regard to this aspect. This requirement can, again as an example, be met by a certain number of source code comment lines or the structure complexity which are software characteristics.

The conceptual level

The conceptual level gives a more detailed description of the high level.

The software quality specification and assessment process starts with a description of the business processes that have to be supported by the software product, the needs (or expectations) of the user/customer and the software product (type) itself (e.g. embedded software or not). Related to the product are issues such as applicable laws, standards and conditions necessary for use of certain hardware or technologies (e.g. operating system).

The software product quality level is described by means of a quality profile based on the ISO 9126 model. A quality specification and an evaluation plan are developed from this. They describe:

which quality specifications will be set for the software to be developed;
which standards, methods, techniques and tools will be used to develop or to evaluate the software with respect to the aspects that were described in the quality profile.

The quality specification is a description of the quality characteristics that have to be fulfilled by the software being developed. This specification is input to the software development process.

The evaluation plan is the formal description of the way the software will actually be evaluated. The end result of the evaluation is the evaluation report. The equivalent of the evaluation plan regarding development is the software architecture and technical plan.

The instrumental and technical level

The instrumental and technical level addresses the operational aspects of the methodology and comprises the methods, techniques and tools (based on the concepts of the conceptual level) to carry out the processes and describe the entities mentioned at the conceptual level. It can be ISO standards, questionnaires, checklists, decision matrices, description methods, guidelines, etc.

The quality profile can be described by means of a number of ISO 9126 characteristics (e.g. 'functionality', 'maintainability', ...) and a level indication of each characteristic (A to D or 'not relevant').

For the transformation process between quality profile and evaluation plan a selection has to be made from a number of standards, methods, techniques and tools such as ISO 9241, ISO 14598, QSEAL, SUMI, Logiscope software, checklists, guidelines, etc. This selection depends on the characteristics to be evaluated. The selection can also be a part of a method.

The transformation process

The first process defined in the conceptual level has been detailed. We present here the first results.

The main objective of this process is to produce the quality profile of the software product from the user needs (the three user categories are: end-user/customer, business, and software product class). A quality profile is intended to be a list of prioritised quality characteristics (and sub-characteristics, as defined by ISO 9126), and of a set of requirements associated to these quality characteristics.

The activities proposed in this process are the following:

To introduce the approach to all persons which will be involved in the process;
To collect data (by questionnaire, checklists...) related to the software product in its contexts of use (technical characteristics, context and conditions of use, features of users...);
To analyse data collected and combine to provide an unformal, accessible and reusable data basis, to identify the potential inconsistencies between the different participants' points of view, to determine potential quality levels (A possible support are predefined requirements/quality levels decision tables, i.e. data base which suggests relationship between a set of common contexts of use and their corresponding quality levels);
To consolidate the combined results by obtaining feedback (inconsistencies resolved, modifications/adjustements to the quality levels initially proposed...);
To elaborate the Quality Profile with the explanations and additional information to support a correct interpretation of the quality profile established, to translate the quality levels into evaluation levels (as defined in the SCOPE project).

The following figure provides a graphical representation of the process activities, including inputs, outputs, mechanisms and controls for each step (the SADT (Specification Analysis Description Technique) method has been used to provide this graphical representation):

Fig. 2: The transformation process to produce the quality profile
This figure is available as a postscript file

	9126 at work
	Quality Characteristics