Feng-n Li

Taking goal models downstream: A systematic roadmap

Creating and reasoning with goal models is useful for capturing, understanding, and communicating about requirements in the early stages of information system (re)development. However, the utility of goal models is greatly enhanced when an awareness of system intentions can feed into other stages in the requirements analysis process (e.g. requirements elaboration, validation, planning), and can be used as part of the entire system life cycle (e.g., architecture, process design, coding, testing, monitoring, adaptation, and evolution). In order to understand the progress that has been made in integrating goal models with downstream system development, we ask: what approaches exist which map/integrate/transform goal-oriented languages to other software artifacts or languages? To answer this question, we conduct a systematic survey, producing a roadmap of work summarizing 174 publications. Results include a categorization of the “why?” and “how?” for each approach. Findings show that there are a wide variety of proposals with many proposed sources and targets, covering multiple paradigms, motivated by a variety of purposes. We conclude that although much work has been done in this area, the work is fragmented and is often still in a proposal stage.

Using Goal Models Downstream: A Systematic Roadmap and Literature Review

Goal models have proven useful for capturing, understanding, and communicating requirements during early stages of software development. However, the utility of goal models is greatly enhanced when they can be exploited during downstream stages of the requirements analysis process (e.g. requirements elaboration, validation, planning), and can be used as part of the entire system life cycle (e.g., architectural and behavioral process design, coding, testing, monitoring, adaptation, and evolution). In order to better understand the progress that has been made in integrating goal models with downstream system development, the authors ask: what approaches exist that map/integrate/transform goal models to later stage software artifacts? To answer this question, they conduct a systematic survey, producing a roadmap of work summarizing 243 publications. Results include a categorization of the “why?†and “how?†for each approach. Furthermore, they select the 50 most prominent publications, based on citation numbers, in order to perform an in-depth literature review. Findings show that there is a wide variety of proposals with a variety of proposed goal models and targets, covering multiple paradigms, motivated by a variety of purposes. The authors conclude that although much work has been done in this area, the work is fragmented, following multiple separate strands of goal-orientation, and is often still in early stages of maturity.

Non-functional requirements as qualities, with a spice of ontology

We propose a modeling language for non-functional requirements (NFRs) that views NFRs as requirements over qualities, mapping a software-related domain to a quality space. The language is compositional in that it allows (recursively) complex NFRs to be constructed in several ways. Importantly, the language allows the definition of requirements about the quality of fulfillment of other requirements, thus capturing, among others, the essence of probabilistic and fuzzy goals as proposed in the literature. We also offer a methodology for systematically refining informal NFRs elicited from stakeholders, resulting in unambiguous, de-idealized, and measurable requirements. The proposal is evaluated with a requirements dataset that includes 370 NFRs crossing 15 projects. The results suggest that our framework can adequately handle and clarify NFRs generated in practice.

From Stakeholder Requirements to Formal Specifications Through Refinement

[Context and motivation] Stakeholder requirements are notoriously informal, vague, ambiguous and often unattainable. The requirements engineering problem is to formalize these requirements and then transform them through a systematic process into a formal specification that can be handed over to designers for downstream development. [Question/problem] This paper proposes a framework for transforming informal requirements to formal ones, and then to a specification. [Principal ideas/results] The framework consists of an ontology of requirements, a formal requirements modeling language for representing both functional and non-functional requirements, as well as a rich set of refinement operators whereby requirements are incrementally transformed into a formal, practically satisfiable and measurable specification. [Contributions] Our proposal includes a systematic, tool-supported methodology for conducting this transformation. For evaluation, we have applied our framework to a public requirements dataset. The results of our evaluation suggest that our ontology and modeling language are adequate for capturing requirements, and our methodology is effective in handling requirements in practice.

Evaluating Modeling Languages: An Example from the Requirements Domain

Modeling languages have been evaluated through empirical studies, comparisons of language grammars, and ontological analyses. In this paper we take the first approach, evaluating the expressiveness and effectiveness of Techne, a requirements modeling language, by applying it to three requirements problems from the literature. We use our experiences to propose a number of language improvements for Techne, addressing challenges discovered during the studies. This work presents an example evaluation of modeling language expressiveness and effectiveness through realistic case studies.

Engineering Requirements with Desiree: An Empirical Evaluation

The requirements elicited from stakeholders suffer from various afflictions, including informality, vagueness, incompleteness, ambiguity, inconsistencies, and more. It is the task of the requirements engineering process to derive from these a formal specification that truly captures stakeholder needs. The Desiree requirements engineering framework supports a rich collection of refinement operators through which an engineer can iteratively transform stakeholder requirements into a specification. The framework includes an ontology, a formal representation for requirements, as well as a tool and a systematic process for conducting requirements engineering. This paper reports the results of a series of empirical studies intended to evaluate the effectiveness of Desiree. The studies consist of three controlled experiments, where students were invited to conduct requirements analysis using textbook techniques or our framework. The results of the experiments offer strong evidence that with sufficient training, our framework indeed helps users conduct more effective requirements analysis.

Software Service Evolution: A Requirements Perspective

Software service has to adapt to constant changes of requirements and environment, which would give rise to the concentration on service evolution. Among the many reasons for evolution, requirements are regarded as the major driving factor. However, most current work on service evolution focuses on different kinds of tactics to keep the compatibility between services and client applications, few of them treat requirements in priority. In this paper, we thoroughly survey the state-of-the-art studies on service evolution, including basic concepts, types, challenges and approaches; then analyze service evolution from four dissimilar dimensions, and for each one we identify the open problems and inadequacies. Based on our analysis and discovery, we argue that requirements driven service evolution would become an essential and promising research direction.