1956133
Enhancing a requirements baseline with scenarios
Scenarios are well recognised as an important strategy towards understanding the interface between the environment and the system as well as a means of eliciting and specifying software behaviour. We adopt a broader view of scenarios. For us, a scenario is an evolving description of situations in the environment. Our proposal is framed by Leite’s work on a client-oriented requirements baseline, which aims to model the external requirements of a software system and its evolution. Scenarios start by describing the environment situations, according to the main actions performed outside the software system. Scenarios also help to clarify the interrelation between functional and non-functional requirements. We have validated our strategy and the related representations based on case studies.
47231847
Enhancing a requirements baseline with scenarios
Scenarios are well recognized as an important strategy towards understanding the interface between the environment and the system, as well as a means to elicit and specify software behavior. We have a broader understanding of scenarios: for us, a scenario is an evolving description of situations in the environment. Our proposal is framed by Leite's (1995) work on a client-oriented requirements baseline, which aims at modeling the external requirements of a software system and its evolution. Scenarios start by describing the environmental situation, according to the main actions performed outside the software system. Scenarios also help the clarification of the interrelation between functional and non-functional requirements. We have validated our strategy and related representations based on case studies of a real situation.
11116452
The object-oriented hypermedia design model
H ypermedia applications typically include complex information , and may allow sophisticated navigation behavior. The Object-Oriented Hypermedia Design Method (OOHDM) [4] uses abstraction and composition mechanisms in an object-oriented framework to, on one hand, allow a concise description of complex information items, and on the other hand, allow the specification of complex navigation patterns and interface transformations. In OOHDM, a hypermedia application is built in a four-step process supporting an incremental or prototype process model. Each step focuses on a particular design concern, and an object-oriented model is built. Classification, aggregation and generalization/specialization are used throughout the process to enhance abstraction power and reuse opportunities. Figure 1 summarizes the steps, products , mechanisms and design concerns in OOHDM. Domain Analysis In this step a conceptual model of the application domain is built using well-known object-oriented modeling principles [3], augmented with some primitives such as attribute perspectives (multiple-valued attributes, similar to HDM perspectives [1]). Conceptual classes may be built using aggregation and generalization/special-ization hierarchies. There is no concern for the types Abstract interface objects, responses to external events, interface transformations Running application
38243163
Querying Hypermedia Applications in an Object-Oriented Framework
7589770
Specifying Quality Characteristics and Attributes for Websites
In this work, we outline more than a hundred characteristics and attributes for the domain of academic sites in order to analyze the quality requirement tree and a way to specify them. These elements are used in a quantitative methodology for assessment, comparison, and ranking processes. The proposed Web-site Quality Evaluation Methodology (QEM) can be a useful approach to assess the quality in different phases of a Web product life cycle. In the academic study, we have observed three different evaluation audiences regarding visitor users: current and prospective students, academic personnel, and research sponsors. Besides, the aim of this work is to show a hierarchical and descriptive specification framework for characteristics, subcharacteristics and attributes. This framework is a key underlying piece in the construction of a hyperdocumented evaluation tool. Finally, some results are presented and concluding remarks are discussed.
707114
Compiling Intensional Sets in CLP
Constructive negation has been proved to be a valid alternative to negation as failure, especially when negation is required to have, in a sense, an ‘active’ role. In this paper we analyze an extension of the original constructive negation in order to gracefully integrate with the management of set-constraints in the context of a Constraint Logic Programming Language dealing with finite sets. We show that the marriage between CLP with sets and constructive negation gives us the possibility of representing a general class of intensionally defined sets without any further extension to the operational semantics of the language. The presence of intensional sets allows a definite increase in the expressive power and abstraction level offered by the host logic language.
12466079
ACI1 constraints
Disuniication is the problem of deciding satissability of a system of equations and disequations w.r.t. a given equational theory. In this paper we study the disuni-cation problem in the context of ACI1 equational theories. We provide a characterization of the interpretation structures suitable to model the axioms in ACI1 theories. The satissability problem is solved using known techniques for the equality constraints and novel methodologies to transform disequation constraints into solved forms. We propose three solved forms, ooering an increasingly more precise characterization of the set of solutions. Two of them can be computed and tested in polynomial time. The novel results achieved open new possibilities in the practical and eecient manipulation of ACI1 constraints.
50781
Multiset constraints and P systems
Multisets are the fundamental data structure of P systems. In this paper we relate P systems with the language and theory for multisets presented in [9.] This allows us, on the one hand, to define and implement P systems using multiset constraints in a constraint logic programming framework, and, on the other hand, to define and implement constraint solving procedures used to test multiset constraint satisfiability in terms of P systems with active membranes. While the former can be exploited to provide a precise formulation of a P system, as well as a working implementation of it, based on a first-order theory, the latter provides a way to obtain a P system for a given problem (in particular, NP problems) starting from a rather natural encoding of its solution in terms of multiset constraints.
405949
Constructive negation and constraint logic programming with sets
The aim of this paper is to extend theConstructive Negation technique to the case ofCLP(SεT), a Constraint Logic Programming (CLP) language based on hereditarily (and hybrid) finite sets. The challenging aspects of the problem originate from the fact that the structure on whichCLP(SεT) is based is notadmissible closed, and this does not allow to reuse the results presented in the literature concerning the relationships betweenCLP and constructive negation.We propose a new constraint satisfaction algorithm, capable of correctly handling constructive negation for large classes ofCLP(SεT) programs; we also provide a syntactic characterization of such classes of programs. The resulting algorithm provides a novel constraint simplification procedure to handle constructive negation, suitable to theories where unification admits multiple most general unifiers. We also show, using a general result, that it is impossible to construct an interpreter forCLP(SεT) with constructive negation which is guaranteed to work for any arbitrary program; we identify classes of programs for which the implementation of the constructive negation technique is feasible.
3157847
Intensional Sets in CLP
We propose a parametric introduction of intensionally defined sets into any \(CLP(\mathcal \{D\})\) language. The result is a language \(CLP({\mathcal \{D\}})\), where constraints over sets of elements of \(\mathcal D\) and over sets of sets of elements, and so on, can be expressed. The semantics of \(CLP({\mathcal \{D\}})\) is based on the semantics of logic programs with aggregates and the semantics of CLP over sets. We investigate the problem of constraint resolution in \(CLP({\mathcal \{D\}})\) and propose algorithms for constraints simplification.