Reasoning of Competitive Non-Functional Requirements in Agent-Based Models

During the decision-making process in real-time competitive environments, there is a need to perform concurrent optimisation of multiple competitive objectives to select an optimal design decision for interdependent stakeholders. To handle such issues, this thesis successfully assimilates the goal-oriented requirements-engineering knowledge with analytical decision-making approaches to facilitate reasoning and analysis by encouraging stakeholders’ involvement. This leads to optimal decisions with domain knowledge improvement in the agent-based i*-goal model by balancing multiple conflicting non-functional requirements reciprocally

Exploiting a Goal-Decomposition Technique to Prioritize Non-functional Requirements

Business stakeholders need to have clear and realistic goals if they want to meet commitments in application development. As a consequence, at early stages they prioritize requirements. However, requirements do change. The effect of change forces the stakeholders to balance alternatives and reprioritize requirements accordingly. In this paper we discuss the problem of priorities to non-functional requirements subjected to change. We, then, propose an approach to help smooth the impact of such changes. Our approach favors the translation of nonoperational specifications into operational definitions that can be evaluated once the system is developed. It uses the goal-question-metric method as the major support to decompose non-operational specifications into operational ones. We claim that the effort invested in operationalizing NFRs helps dealing with changing requirements during system development. Based on\ud this transformation and in our experience, we provide guidelines to prioritize volatile non-functional requirements

AHP based Optimal Reasoning of Non-functional Requirements in the i∗ Goal Model

Goal-Oriented Requirements Engineering (GORE) has been found to be a valuable tool in the early stages of requirements engineering. GORE plays a vital role in requirements analysis like alternative design/ goal selection during decision-making. The decision-making process of alternative design/ goal selection is performed to assess the practicability and value of alternative approaches towards quality goals. Majority of the GORE models manage alternative selection based on qualitative approach, which is extremely coarse-grained, making it impossible for separating two alternatives. A few works are based on quantitative alternative selection, yet this does not provide a consistent judgement on decision-making. In this paper, Analytic Hierarchy Process (AHP) is modified to deal with the evaluation of selecting the alternative strategies of inter-dependent actors of i∗ goal model. The proposed approach calculates the contribution degrees of alternatives to the fulfilment of top softgoals. It is then integrated with the normalized relative priority values of top softgoals. The result of integration helps to evaluate the alternative options based on the requirements problem against each other. To clarify the proposed approach, a simple telemedicine system is considered in this paper

Optimal Reasoning of Opposing Non-functional Requirements based on Game Theory

Goal-Oriented Requirement Engineering is a modeling technique that represents software system requirements using goals as goal models. In a competitive environment, these requirements may have opposing objectives. Therefore, there is a requirement for a goal reasoning method, which offers an alternative design option that achieves the opposing objectives of inter-dependent actors. In this paper, a multi-objective zero-sum game theory-based approach is applied for choosing an optimum strategy for dependent actors in the i* goal model. By integrating Java with IBM CPLEX optimisation tool, a simulation model based on the proposed method was developed. A successful evaluation was performed on case studies from the existing literature. Results indicate that the developed simulation model helps users to choose an optimal design option feasible in real-time competitive environments

Evaluating Security Assurance Case Adaptation

Security certification processes for information systems involve expressing security controls as functional and non-functional requirements, monitoring deployed mechanisms that satisfy the requirements, and measuring the degree of confidence in system compliance. With the potential for systems to perform runtime self-adaptation, functional changes to remedy system performance may impact security control compliance. This impact can extend throughout a network of related controls causing significant degradation to the system’s overall compliance status. We represent security controls as security assurance cases and implement them in XML for management and evaluation. The approach maps security controls to softgoals, introducing achievement weights to the assurance case structure as the foundation for determining security softgoal satisficing levels. Potential adaptations adjust the achievement weights to produce different satisficing levels. We show how the levels can be propagated within the network of related controls to assess the overall security control compliance of a potential adaptation

A goal-oriented approach for the generation and evaluation of alternative architectures

There is a recognized gap between requirements and architectures. There is also evidence that architecture evaluation, when done at the early phases of the development lifecycle, is an effective way to ensure the quality attributes of the final system. As quality attributes may be satisfied at a different extent by different alternative architectural solutions, an exploration and evaluation of alternatives is often needed. In order to address this issue at the requirements level, we propose to model architectures using the i* framework, a goal-oriented modelling language that allows to represent the functional and non-functional requirements of an architecture using actors and dependencies instead of components and connectors. Once the architectures are modelled, we propose guidelines for the generation of alternative architectures based upon existing architectural patterns, and for the definition of structural metrics for the evaluation of the resulting alternative models. The applicability of the approach is shown with the Home Service Robot case study.Peer ReviewedPostprint (author's final draft