On Notification Importance for Online Social Network Users

Over the last decade, online social networks (OSNs) have been growing quickly to become some of the largest systems in use. Their users are sharing more and more content, and in turn have access to vast amounts of information from and about each other. This increases the risk of information overload for every user. We…

Agile Requirements Evolution via Paraconsistent Reasoning

Innovative companies need an agile approach towards product and service requirements, to rapidly respond to and exploit changing conditions. The agile approach to requirements must nonetheless be systematic, especially with respect to accommodating legal and non-functional requirements. This paper examines how to support lightweight, agile requirements processes which can still be systematically modeled, analyzed and…

Legal Compliance of Roles and Requirements

The problem of regulatory compliance for a software system consists of ensuring through a systematic, tool-supported process that the system complies with all elements of a relevant law. To deal with the problem, we build a model of the law and contrast it with a model of the requirements of the system. In earlier work,…

An Overview of Requirements Evolution

Changing requirements are widely regarded as one of the most significant risks for software systems development. However, in today’s business landscape, these changing requirements also represent opportunities to exploit new and evolving business conditions. In consonance with other agile methods, we advocate requirements engineering techniques that embrace and accommodate requirements change. This agile approach to…

The Requirements Problem for Adaptive Systems

Requirements Engineering (RE) focuses on eliciting, modeling, and analyzing the requirements and environment of a system-to-be in order to design its specification. The design of the specification, known as the Requirements Problem (RP), is a complex problem-solving task because it involves, for each new system, the discovery and exploration of, and decision making in a…

Knowledge-Based Recommendation Systems: A Survey

Knowledge-Base Recommendation (or Recommender) Systems (KBRS) provide the user with advice about a decision to make or an action to take. KBRS rely on knowledge provided by human experts, encoded in the system and applied to input data, in order to generate recommendations. This survey overviews the main ideas characterizing a KBRS. Using a classification…

An Exploratory Study of Topic Importance in Requirements Elicitation Interviews

Interviewing stakeholders is a common way to elicit information about requirements of the system-to-be and the conditions in its operating environment. One difficulty in preparing and doing interviews is how to avoid missing the information that may be important to understand the requirements and environment conditions. Some information may remain implicit throughout the interview, if…

Context Factors and Requirements Problems

When eliciting requirements, it is important to understand why some information may remain implicit, while other are shared by stakeholders. This requires knowing which variables influence if an individual shares implicit information during requirements elicitation. Based on our past experimental work on decision-making, we identify variables – Context Factors (CFs) – which influence whether implicit…

Toward Benchmarks to Assess Advancement in Legal Requirements Modeling

As software engineers create and evolve information systems to support business practices, these engineers need to address constraints imposed by laws, regulations and policies that govern those business practices. Requirements modeling can be used to extract important legal constraints from laws, and decide how, and evaluate if an information system design complies to applicable laws….

Adaptability of Process-based Service Compositions

When implementing (semi-)automatic business processes with services, engineers are facing two sources of variability. One source of variability are alternative refinements and decompositions of requirements. The other source of variability is that various (combinations of) services can be used to satisfy the same requirements. We suggest a method based on the use of a goal…

Choosing Compliance Solutions through Stakeholder Preferences

Compliance to relevant laws is increasingly recognized as a critical, but also expensive, quality for software requirements. Laws contain elements such as conditions and derogations that generate a space of possible compliance alternatives. During requirements engineering, an analyst has to select one of these compliance alternatives and ensure that the requirements specification she is putting…

Product Portfolio Scope Optimization based on Features and Goals

In this paper we propose a mathematical program able to optimize the product portfolio scope of a software product line and sketch both a development and a release planning. Our model is based on the description of customer needs in terms of goals. We show that this model can be instantiated in several contexts such…

Influence of Context on Decision Making during Requirements Elicitation

Requirements engineers should strive to get a better insight into decision making processes. During elicitation of requirements, decision making influences how stakeholders communicate with engineers, thereby affecting the engineers’ understanding of requirements for the future information system. Empirical studies issued from Artificial Intelligence offer an adequate groundwork to understand how decision making is influenced by…

Context-driven Elicitation of Default Requirements

In Requirements Engineering, requirements elicitation aims the acquisition of information from the stakeholders of a system-to-be. An important task during elicitation is to identify and render explicit the stakeholders’ implicit assumptions about the system-to-be and its environment. Purpose of doing so is to identify omissions in, and conflicts between requirements. This paper offers a conceptual…

Requirements Engineering Methods: A Classification Framework

Requirements Engineering Methods (REMs) support Requirements Engineering (RE) tasks, from elicitation, through modeling and analysis, to validation and evolution of requirements. Despite the growing interest to design, validate and teach REMs, it remains unclear what components REMs should have. A classification framework for REMs is proposed. It distinguishes REMs based on the domain-independent properties of…

Analysis and Design of Advice

Advice involves recommendations on what to think; through thought, on what to choose; and via choices, on how to act. Advice is information that moves by communication, from advisors to the recipient of advice. This book offers a general way to analyze advice. The analysis applies regardless of what the advice is about and from…

Finding Incremental Solutions for Evolving Requirements

This paper investigates aspects of the problem of software evolution resulting from top-level requirements change. In particular, while most research on design for software focuses on finding some correct solution, this ignores that such a solution is often only correct in a particular, and often short-lived, context. Using a logic-based goal-oriented requirements modeling language, the…

Towards Conceptual Foundations of Requirements Engineering for Services

A service-oriented system should be engineered to satisfy the requirements of its stakeholders. Requirements are understood in terms of stakeholder goals, softgoals, quality constraints, preferences, tasks, and domain assumptions. The service-oriented system is viewed in terms of services, mediators, choreographies, and orchestrations, among others. To engineer the system according to requirements, it is necessary to…

Requirements Engineering for Self-Adaptive Systems: Core Ontology and Problem Statement

The vision for self-adaptive systems (SAS) is that they should continuously adapt their behavior at runtime in response to changing user’s requirements, operating contexts, and resource availability. Realizing this vision requires that we understand precisely how the various steps in the engineering of SAS depart from the established body of knowledge in information systems engineering….

Establishing Information System Compliance via Argumentation

This paper introduces a mixed modeling and argumentation framework applied to assess the compliance of requirements with legal norms, and reports the results of its application in an industrial project in healthcare. Domain experts applied a goal-oriented modeling framework for the representation of requirements and norms, then used argumentation techniques to assess the compliance of…

Techne Family of Formalisms for the Resolution of Requirements Problems

Between 2010 and 2013, I argued that Techne should be extended into a family of formalisms; this was related to some extent to the idea that Techne is an “abstract” requirements modeling language, something that a reviewer remarked in relation to the original Techne paper here. This led to a lot of discussions and writing…

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…