Ambrosio Toval Álvarez

Formally modeling UML and its evolution: a holistic approach

Due to the pervasiveness of diagrams in human communication and because of the increasing availability of graphical notations in Software Engineering, the study of diagrammatic notations is at the forefront of many research efforts. The expressive power of these kinds of languages and notations can be remarkably improved by adding extensibility mechanisms Extensibility, the ability of a notation or a modeling language to be extended from its own modeling constructs, is a feature that has assumed considerable importance with the appearance of the UML (Unified Modeling Language). In this paper, a holistic proposal to formally support the evolution of the UML metamodel is presented. To attain this aim, an algebraic formalization is provided which leads to a seamless formal model of the UML four-layer semantics architecture. These two characteristics — being holistic and seamless together with reflection are the most innovative aspects of the research with respect to formalizing the UML. In particular, a central role is played by reflection. A formal language supporting this feature called Maude is studied and put forward as the basis for the formalization of the UML extensibility mechanisms. Since Maude is an executable specification language, the final set of formal models can also be used as a UML virtual machine at the specification level. To illustrate the approach, a UML Class Diagram prototype is implemented using the Maude interpreter. The integration of this Maude prototype with a UML commercial CASE has been developed, in Java, and is currently working.

Can intuition become rigorous? Foundations for UML model verification tools

The Unified Modeling Language, UML, is the object oriented notation adopted as the standard for object oriented analysis and design by the Object Management Group. The paper reports on research to facilitate the formal revision of UML informal specifications. The approach is based on algebraic specification formal theory, which is used to formalize the UML Statechart diagrams and subsequently verify them. To illustrate the proposal, the so-called orthogonality property is investigated. This property is modeled at the UML metamodel level so that its fulfillment on the part of any particular UML Statechart diagram can be mathematically proven or disproven. The formal models obtained are specified in the executable formal language Maude, thus providing the additional advantage of using them as functional prototypes. These results lead to a whole formalization of the UML, which can be used in practice, and lay the foundations for the construction of rigorous UML CASE tools.

A precise approach for the analysis of the UML models consistency

The UML notation is a well-know standard notation to describe OO systems. But the UML specification has certain imprecisions and ambiguities that, along with possible errors made by the modellers, may cause inconsistency problems in the models of the system. This paper presents a rigorous approach to improve the consistency analysis between UML diagrams. This proposal is based on a previous formalization of the UML metamodel diagrams, [1,4] in Maude. The framework given by the specifications created helps to guarantee the consistency of models because all the specifications are integrated within the same formalism. This work focuses on the analysis of the inter-diagram consistency. Several examples of properties are shown that help to guarantee the consistency between UML Communication and Class Diagrams.

Precise wis development

In recent years, Internet has become the platform that supports most areas in organizations. This fact has led to the appearance of specific tools for the construction of Web Information Systems (WIS). However, in these tools an absence of functionalities for verification and validation (V&V) of the models built has been detected. This work aims to redress this absence with the definition of a strategy for the specification of the models used in the WIS development that can be used with V&V objectives. The approach has been validated in a specific methodology (MIDAS) and an associated tool (MIDAS-CASE), both aligned with the MDA proposal. One of the diagrams used in this methodology has been formalized: the extended navigation model, achieving a precise specification of this diagram. This specification permits the definition and formal verification of properties related to this diagram, as well as its validation. The specification and verification of a concrete property are also shown.

Knowledge Clustering Using a Neural Network in a Course on Medical-Surgical Nursing

This paper presents a neural network-based intelligent data analysis for knowledge clustering in an undergraduate nursing course. A MCQ (Multiple Choice Question) test was performed to evaluate medical-surgical nursing knowledge in a second-year course. A total of 23 pattern groups were created from the answers of 208 students. Data collected were used to provide customized feedback which guide students towards a greater understanding of particular concepts. The pattern groupings can be integrated with an on-line (MCQ) system for training purposes.

A generic approach to improve navigational model usability based upon requirements and metrics

In recent years, the fast evolution of Internet and the Web has caused an exponential increase in the number of Web Information Systems (WIS) developed. This has led to the appearance of a new discipline, Web Engineering, which has served as a framework for the development of numerous methodologies and tools which seek to contribute to the development of WIS with the quality parameters required by their users. Among the quality attributes of a WIS are accessibility, usability and the easy of navigation offered by the system. These attributes are usually analyzed when the WIS has been developed, using strategies like the analysis of the HTML code of the WIS or the evaluation of the system by a group of users. This paper presents a proposal to extend the models used in the methodologies for WIS development and to define a set of quality metrics so that modelers can consider usability requirements during WIS modelling. The automatic support for this proposal and the metamodel extension necessary for its integration into the existing methodologies for WIS development are also presented.