| | | |

Requirements Oracles

A requirements database contains the information elicited or otherwise collected, used, and produced during requirements engineering. From a requirements database, the requirements oracle selects information relevant for the resolution of the requirements problem, such as which goals aresatisfied, which domain assumptions are violated or maintained, which tasks cannot be executed together. Implemented oracles should enable…

| | |

Mixed-Variable Requirements Roadmaps for Adaptive Systems

The requirements roadmap concept is introduced as a solution to the problem of the requirements engineering of adaptive systems. The concept requires a new general definition of the requirements problem which allows for quantitative (numeric) variables, together with qualitative (binary boolean) propositional variables, and distinguishes monitored from controlled variables for use in control loops. We…

| | |

Reasoning with Optional and Preferred Requirements

Of particular concern in requirements engineering is the selection of requirements to implement in the next release of a system. To that end, there has been recent work on multi-objective optimization and user-driven prioritization to support the analysis of requirements trade-offs. Such work has focused on simple, linear models of requirements; in this paper, we…

| | | | |

Techne: Towards a New Generation of Requirements Modeling Languages

Techne is an abstract requirements modeling language that lays formal foundations for new modeling languages applicable during early phases of the requirements engineering process. During these phases, the requirements problem for the system-to-be is being structured, its candidate solutions described and compared in terms of how desirable they are to stakeholders. We motivate the need…

| |

Normative Management of Web Service Level Agreements

Service Level Agreements (SLAs) are used in Service- Oriented Computing to define the obligations of the parties involved in a transaction. SLAs define these obligations, including for instance the expected service levels to be delivered by the provider, and the payment expected from the client. The obligations of the parties must be made explicit prior…

| | |

Theory of Regulatory Compliance for Requirements Engineering

Regulatory compliance is increasingly being addressed in the practice of requirements engineering as a main stream concern. This paper points out a gap in the theoretical foundations of regulatory compliance, and presents a theory that states (i) what it means for requirements to be compliant, (ii) the compliance problem, i.e., the problem that the engineer…

From Decision Theory to Techne, and back
| | |

From Decision Theory to Techne, and back

I gave two talks on the topic of qualitative decision analysis, which is what Techne was designed to support. At the time, we were looking for conceptual foundations for doing qualitative decision analysis, an alternative to standard decision analysis, which assumes richer information than what we typically have during requirements engineering and system design. Much…

| | | |

Acceptability Condition for the Relative Validity of Requirements

A requirements engineering artifact is valid relative to the stakeholders of the system-to-be if they agree on the content of that artifact. Checking relative validity involves a discussion between the stakeholders and the requirements engineer. This paper proposes (i) a language for the representation of information exchanged in a discussion about the relative validity of…

| | | |

A Core Ontology for Requirements

In their seminal paper (ACM T. Softw. Eng. Methodol., 6(1) (1997), 1–30), Zave and Jackson established a core ontology for Requirements Engineering (RE) and used it to formulate the “requirements problem”, thereby defining what it means to successfully complete RE. Starting from the premise that the stakeholders of the system-to-be communicate to the software engineer…

| | |

A Comprehensive Quality Model for Service-oriented Systems

In a service-oriented system, a quality (or Quality of Service) model is used (i) by service requesters to specify the expected quality levels of service delivery; (ii) by service providers to advertise quality levels that their services achieve; and (iii) by service composers when selecting among alternative services those that are to participate in a…

| | | |

Dealing with Quality Tradeoffs during Service Selection

In a service-oriented system (SoS) service requests define tasks to execute and quality of service (QoS) criteria to optimize. A service request is submitted to an automated service selector in the SoS, which allocates tasks to those service that, together, can “best” satisfy the given QoS criteria. When the selector cannot optimize simultaneously the given…

| | | |

Clear Justification of Modeling Decisions for Goal-oriented Requirements Engineering

Representation and reasoning about goals of an information system unavoidably involve the transformation of unclear stakeholder requirements into an instance of a goal model. If the requirements engineer does not justify why one clear form of requirements is chosen over others, the subsequent modeling decisions cannot be justified either. If arguments for clarification and modeling…

| | | |

Timing Nonfunctional Requirements

Analysis of temporal properties of nonfunctional – i.e., quality – requirements (NFRs) has not received significant attention. In response, this paper introduces basic concepts and techniques needed for the specification and analysis of time properties of NFRs. Jureta, I.J. and Faulkner, S., 2008, October. Timing Nonfunctional Requirements. In International Conference on Conceptual Modeling (pp. 302-311). Springer, Berlin,…

| | |

Context-Driven Autonomic Adaptation of Service Level Agreements

Service Level Agreements (SLAs) are used in Service-Oriented Computing to define the obligations of the parties involved in a transaction. SLAs define the service users’ Quality of Service (QoS) requirements that the service provider should satisfy. Requirements defined once may not be satisfiable when the context of the web services changes (e.g., when requirements or…

| | | | |

Revisiting the Core Ontology and Problem in Requirements Engineering

In their seminal paper in the ACM Transactions on Software Engineering and Methodology, Zave and Jackson established a core ontology for Requirements Engineering (RE) and used it to formulate the “requirements problem”, thereby defining what it means to successfully complete RE. Given that stakeholders of the system-to-be communicate the information needed to perform RE, we…

| | | |

Engineering Pluripotent Information Systems

A pluripotent information system is an open and distributed information system that (i) automatically adapts at runtime to changing operating conditions, and (ii) satisfies both the requirements anticipated at development time, and those unanticipated before but relevant at runtime. Engineering pluripotency into an information system therefore responds to two recurring critical issues: (i) the need…

| | |

Capturing and Using QoS Relationships to Improve Service Selection

In a Service-Oriented System (SOS), service requesters specify tasks that need to be executed and the quality levels to meet, whereas service providers advertise their services’ capabilities and the quality levels they can reach. Service selectors then match to the relevant tasks, the candidate services that can perform these tasks to the most desirable quality…

| | |

Continually Learning Optimal Allocations of Services to Tasks

Open service-oriented systems which autonomously and continually satisfy users’ service requests to optimal levels are an appropriate response to the need for increased automation of information systems. Given a service request, an open service-oriented system interprets the functional and nonfunctional requirements laid out in the request and identifies the optimal selection of services-that is, identifies…

| | | |

Clarifying Goal Models

Representation and reasoning about information system (IS) requirements is facilitated with the use of goal models to describe the desired and undesired IS behaviors. One difficulty in goal modeling is arriving at a shared understanding of a goal model instance, mainly due to different backgrounds of the system stakeholders who participate in modeling, and the…

| | | | |

Tracing the Rationale Behind UML Model Change Through Argumentation

Neglecting traceability—i.e., the ability to describe and follow the life of a requirement—is known to entail misunderstanding and miscommunication, leading to the engineering of poor quality systems. Following the simple principles that (a) changes to UML model instances ought be justified to the stakeholders, (b) justification should proceed in a structured manner to ensure rigor…

| | |

Dynamic Web Service Composition within a Service-Oriented Architecture

Increasing automation requires open, distributed, service-oriented systems capable of multicriteria-driven, dynamic adaptation for appropriate response to changing operating conditions. We combine a simple architecture with a novel algorithm to enable openness, distribution, and multi-criteria-driven service composition at runtime. The service-oriented architecture involves mediator Web services coordinating other Web services into compositions necessary to fulfill user…

| | | | |

Achieving, Satisficing, and Excelling

Definitions of the concepts derived from the goal concept (including functional and nonfunctional goal, hardgoal, and softgoal) used in requirements engineering are discussed, and precise (and, when appropriate, mathematical) definitions are suggested. The concept of satisficing, associated to softgoals is revisited. A softgoal is satisficed when thresholds of some precise criteria are reached. Satisficing does…

| | | | |

Dynamic Requirements Specification for Adaptable and Open Service-Oriented Systems

It is not feasible to engineer requirements for adaptable and open service-oriented systems (AOSS) by specifying stakeholders’ expectations in detail during system development. Openness and adaptability allow new services to appear at runtime so that ways in, and degrees to which the initial functional and nonfunctional requirements will be satisfied may vary at runtime. To…

| | | |

Allocating Goals to Agent Roles During Multi-Agent Systems Requirements Engineering

Allocation of goal responsibilities to agent roles in Multi-Agent Systems (MAS) influence the degree to which these systems satisfy nonfunctional requirements. This paper proposes a systematic approach that starts from nonfunctional requirements identification and moves towards agent role definition guided by the degree of nonfunctional requirements satisfaction. The approach relies on goal-dependencies to allow potential…

| | | |

A More Expressive Softgoal Conceptualization for Quality Requirements Analysis

Initial software quality requirements tend to be imprecise, subjective, idealistic, and context-specific. An extended characterization of the common Softgoal concept is proposed for representing and reasoning about such requirements during the early stages of the requirements engineering process. The types of information often implicitly contained in a Softgoal instance are highlighted to allow richer requirements…

| | |

Justifying Goal Models

Representation and reasoning about information system (IS) requirements is facilitated with the use of goal models to describe the desired and undesired IS behaviors. One difficulty in building and using goal models is in knowing why a model instance is as it is at some point of the requirements engineering (RE) process. If justifications for…

| | |

An Agent-Oriented Meta-model for Enterprise Modelling

The model identifies constructs that enable capturing the intrinsic characteristics of an agent system such as autonomy, intentionality, sociality, identity and boundary, or rational self- interest; an agent being an organizational actor and/or a software component. Such an approach of the concept of agent allows the analyst to have a holistic perspective integrating human and…

| | |

Formalizing Agent-Oriented Enterprise Models

This paper proposes an agent-oriented metamodel that provides rigorous concepts for conducting enterprise modelling. The aim is to allow analysts to produce an enterprise model that precisely captures the knowledge of an organization and of its business processes so that an agent-oriented requirements specification of the system-to-be and its operational corporate environment can be derived…