Research On Trustworthy Software Quality Attributes Evaluation Methods Based On User Requirements

Abstract:With the widespread use of computer and rapid development of network technology, software has penetrated into all fields of the national economy as well as national defense construction, and been a very important part of human life. Followed by the increasing the size and complexity of software, it is very difficult to control the risk of software and is very frequent that the disastrous events have happened due to software defects or failures. Development of High Confidence Software has become a strategic high ground of the current international software technology development, which has caused a widespread concern in the human society.Trustworthy software evaluation based on multi-quality-attributes becomes the core foundation to achieve software trustworthiness and carry out the management of trustworthy software, which is also an urgently resolved problem in the process of trustworthy software development and management. Currently, the major research on quality attributes of software is based on the developer's perspective, ignoring the objective practice and subjective experience of software users in the process of using software. So the research based on user requirements in the field of trustworthy software has become very important for theory and practice.This paper discusses the definition of trustworthy software and quality attributes firstly, particularly pays attention to overseas and domestic research status about them, and summarizes several major software quality models, researches on software quality metrics from three aspects of development, classification and procedure. All these are the basic work to research trustworthy software quality attributes.It is not only a basic work but also a crucial step to build the index system of trustworthy software quality attributes for evaluating them. Based on the users'requirements and the features of trustworthy software, this paper divides the quality attributes into two categories, which are key attributes and non-key attributes respectively. And after building the quality attributes evidence model and the quality evaluation system for trustworthy software, an evaluational criteria system for meeting user requirement is built. All these are the basis to evaluation method for trustworthy software quality attributes.The first evaluation method of trustworthy software quality attributes in this paper is an indirect method, which considers that software users and software developers should have a consistent evaluation for quality attributes. Because some quality attributes can't be measured accurately or be compared directly, this paper researches the interrelation of quality attributes in the component, proposes design structure matrix to describe their interrelation, and computer their relative importance by matrix shift. Meanwhile, the running environment of trustworthy software is different, and different people have different perspectives, different explanation and different criteria, they can't gain the consistent criteria to a large degree when evaluating quality attributes. With respond to these difficulties, this paper poses an evaluation method based on above measurement model and three indices. Compared with other methods, our approach depends on the interrelation of quality attributes, which make result objective and have a unified standards and evaluation criteria, considering the consistency of software users and developers for evaluation result.The second evaluation method of trustworthy software quality attributes in this paper is a direct method, which considers the valuators' bounded rationality. Most evaluation methods in the past have suppoosed that the evalutor are entire rationality, but in fact all kinds of subjective factors, such as risk preference, subjective preference, affect the valuator's evaluation result. This paper introduces the prospect theory, which is widely used in the field of psychology and behavioral science. Found the positive, negative ideal solution in the framework, the comprehensive prospect value of software quality attributes can be calculated and ranked to find the best software quality attributes. Because in the evaluation process the risk preference from valuators can affect result, we further analyze relevant parameters in the prospect theory, which make our method more rigorous and more scientific.The third evaluation method of trustworthy software quality attributes in this paper is a dynamic method, considering whether the evaluation result of quality attributes will change, how change, and whether software is trustworthy when the software suffers interference or continuous interference. Software system is a dynamic system with constant development and evolution, when disturbed, the system always is expected to maintain the original state, but in reality it is not always possible. It is inevitable that energy changes in the system with the changing of statement, the paper uses entropy, a physics concepts, to describe the phenomenon. When software suffered interference, its status change shows that it is completely discrete process in time and space, and the subsequent state is affected by previous one. The cellular automation can meet these conditions and simulate this process to gain the evaluation result of software quality attributes.This paper evaluates the trustworthy software quality attributes based on the perspective of software user requirement indirectly, directly and dynamic. It is benefit to evaluate the quality attributes objectively for the software users and to provide an objective basis for software developers, who consider users'requirement a bit more in the process of designing the software.