Although the term 'non-functional requirement' has been in use for more than 20 years, there is still no consensus in the requirements engineering community what non-functional requirements are and how we should elicit, document, and validate them. On the other hand, there is a unanimous consensus that non-functional requirements are important and can be critical for the success of a project. This paper surveys the existing definitions of the term, highlights and discusses the problems with the current definitions, and contributes concepts for overcoming these problems.

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On Non-Functional Requirements

Survey: A survey on search-based software design

It is of general agreement that quality issues should be considered very early in the software development process, to mitigate risks and to facilitate the achievement of the overall software system. Moreover, the architecture of the system drives the whole development process. The fulfillment of nonfunctional quality requirements by a candidate architecture is crucial to select the convenient architecture on which the whole system will be articulated. This issue is very important in the construction of reliable evolutionary applications. Software development methods do not give many details on this important stage. This work deals with the specification of quality requirements for software architecture, introducing a technique based on the ISO 91261 standard. The quality characteristics of the ISO quality model are refined into attributes, which can be measured to enrich the information about the architecture. Our technique is used to help selecting a suitable architecture among a set of candidates, by comparing the values of the respective quality attributes. A case study illustrates the application of the technique on a monitoring system. Our approach facilitates the choice of the right decisions during the architecture analysis process. It could be easily integrated into a general software development process or into specific architectural design methods.

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Quality Characteristics for Software Architecture.

As in every engineering discipline, metrics play an important role in software development, with the difference that almost all software projects need the customization of metrics used. In other engineering disciplines, the notion of a measurement system (i.e. a tool used to collect, calculate, and report quantitative data) is well known and defined, whereas it is not as widely used in software engineering. In this paper we present a framework for developing custom measurement systems and its industrial evaluation in a software development unit within Ericsson. The results include the framework for designing measurement systems and its evaluation in real life projects at the company. The results show that with the help of ISO/IEC standards, measurement systems can be effectively used in software industry and that the presented framework improves the way of working with metrics. This paper contributes with the presentation of how automation of metrics collection and processing can be successfully introduced into a large organization and shows the benefits of it: increased efficiency of metrics collection, increased adoption of metrics in the organization, independence from individuals and standardized nomenclature for metrics in the organization.

A framework for developing measurement systems and its industrial evaluation

The process of measuring in software engineering has already been standardized in the ISO/IEC 15939 standard, where activities related to identifying, creating, and evaluating of measures are described. In the process of measuring software entities, however, an organization usually needs to create custom measurement systems, which are intended to collect, analyze, and present data for a specific purpose. In this paper, we present a proven industrial process for developing measurement systems including the artifacts and deliverables important for a successful deployment of measurement systems in industry. The process has been elicited during a case study at Ericsson and is used in the organization for over 3 years when the paper was written. The process is supported by a framework that simplifies the implementation of the measurement systems and shortens the time from the initial idea to a working measurement system by the factor of 5 compared with using a standard development process not tailored for measurement systems. Copyright © 2010 John Wiley & Sons, Ltd.

Developing measurement systems: an industrial case study

The main concern of this paper is measuring the quality of the architectural design. The goal of this work is to use the architectural design process proposed in the unified process framework, adapting and detailing it to include the quality requirements specification at architectural level. There is general agreement on the fact that in modern applications the selection of the architecture must be addressed early in the development process, to mitigate risks. Moreover, the integration of enterprise applications is a component-based development requiring quality values associated to the services offered by the components. The services depend mostly on the architecture. In consequence, methods arise for guiding the selection or for constructing software architectures. Our approach allows associating the quality requirements (nonfunctional properties) for the architecture expressed using the ISO 9126-1 standard quality model, with the use cases, to facilitate the selection of the “key” use cases. Measures for the architecture's quality characteristics are specified in details, precising attributes, units, numerical systems and scale types. A case study of a real-time application for monitoring stock exchanges illustrates our approach. We hope that our results will be particularly useful for practitioners, such as software architects, analysts and designers.

ISO quality standards for measuring architectures

Characterizing a data model for software measurement

We address the problems related with the construction of quality software systems. A generally accepted claim is that the evaluation and control of each stage of development in a well-defined process will improve the overall quality of the final software product. In particular, we are interested in the early analysis and design stages, where the architecture of the system is an intermediate product. Several approaches are discussed, where quality models are established in order to determine the influence of the system non-functional characteristics, as part of the software initial requirements, on the final software system. These characteristics affect mostly the software system structure or architecture. The main goal is to discuss three important approaches based on quality models: ISO 9126, Dromey and ABAS (Attribute-Based Architectural Styles), and establish several criteria or points of comparison.

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Ledis Chirinos

Papers

Quality Characteristics for Software Architecture.

ISO quality standards for measuring architectures

ISO quality standards for measuring architectures

Characterizing a data model for software measurement

Quality models to design software architectures