Catálogo de publicaciones - libros

The Unified Modeling Language (UML) has been widely accepted as the standard object-oriented (OO) modeling language for modeling various aspects of software and information systems. The UML is an extensible language, in the sense that it provides mechanisms to introduce new elements for specific domains if necessary, such as web applications, database applications, business modeling, software development processes, data warehouses and so on. Furthermore, the latest approach of the Object Management Group (OMG) surrounding the UML even got bigger and more complicated with a more number of diagrams with some good reasons. Although providing different diagrams for modeling specific parts of a software system, not all of them need to be applied in most cases. Therefore, heuristics, design guidelines, lessons learned from experiences are extremely important for the effective use of UML and to avoid unnecessary complication.

Despite widespread interest in the Unified Modeling Language (UML), there is little evidence about the extent and nature of UML use. This paper reports results of a survey of UML use by practitioners. Results indicate varying levels of use, and perceived usefulness, of different UML diagrams. In addition, we found significant involvement of non-IT professionals in the development of UML diagrams. An understanding of the range of current practices is an important foundation for determining “best practices.”

As UML statechart diagrams are the core for modeling the dynamic aspects of software systems, we have been studying their understandability for the last three years. In previous researches, we have already studied the relationship between many of the constructs of the UML statechart diagrams and the effect that they have on the understandability of the diagrams themselves. We have also performed a family of experiments whose results indicated that the use of composite states make UML statechart diagrams easier to understand. This fact motivated us to go a step further and investigate if the Nesting Level of Composites States (NLCS) has an impact on the understanding of the diagrams through a controlled experiment and a replication. In this paper, we present the experimental process and the main findings of them. Unfortunately, the obtained results are not quite conclusive and we have not been able to find an optimal use of nesting within UML statechart diagrams and further empirical research is needed, considering more complex UML statechart diagrams.

To support the design of data models for multimedia applications, we employ the concept of a framework introduced in object-oriented design. We define a UML framework, which can be used for deriving application-specific multimedia database models. With the UML framework, we define the core elements of a multimedia database model, such as mediatype- and application-independent structure, content, relationships and operations. Thereby, the advantages of using UML for representing multimedia data as well as shortcomings of this approach are discussed. Furthermore, we describe the utilization of the UML framework for the instantiation of a model for an image database of scanned handwritten music scores.

In UML class diagrams, a many-to-many relationship with attributes can be represented by an association class or by a connecting object class. It is unclear which modeling construct is preferred in particular modeling scenarios. Because of lack of theory, this paper investigates the issue empirically. An experiment was conducted that tested the effect of representational form chosen on the performance of model users at cardinality interpretation tasks. It was shown that, controlling for cardinality knowledge, business users can better interpret the information that a UML class diagram conveys about a many-to-many relationship with attributes if this relationship is represented as an association class. The implication for ‘best practices’ in UML modeling is that modelers should refrain from objectifying such relationships if the goal is an effective communication of domain semantics to users that are not modeling experts.

The UML recommends that software system functionality and interactions be documented through use case narrative descriptions and use case diagrams. The UML, however, provides no structure or framework for organizing a large number of use cases that may be required for complex systems. In this paper, we present various taxonomies of existing use case classification schemes and one additional scheme for classifying and organizing use cases. We then discuss how we can effectively understand categorized use cases in terms of project priority and personnel skills to achieve the best possible allocation of project resources to use case-driven development efforts. The proposed method uses simple sequential questions to determine use case categories to aid analyzers in real-world projects. Our method is moderately simple to understand and implement.

Use case relationships are used to manage the complexity of use cases. The UML defines the three types of use case relationships: include, extend, and generalization. The appropriate use of the use case relationships, however, is one of the most contentious areas. We found that the suggestions of various authors overlap but conflict, leaving room for dissension. In this paper, we present a comparative analysis of the use case relationships discussed in eleven literatures, including the UML 2.0 specification. For a coherent approach for applying use case relationships, we present three rules derived from the review of the literatures and our own experience and illustrates the rules with examples. Our rules are based on the analysis of preconditions, postconditions of use cases, and characteristics of the behaviors being separated.

Nowadays, the maturity reached by the Web engineering research community can be assessed by the myriad of web design methods that have proven successful for the specification of the functional and navigational requirements posed by Web information systems. However, these proposals often fail to address architectural features, which results in Web specifications with rigid architectures, with no regard for their actual circumstances of use. To overcome this limitation, we propose a generic approach called WebSA. WebSA is based on the MDA (Model-driven Architecture) paradigm. It proposes a Model Driven Development made up of a set of UML architectural models and QVT transformations as mechanisms to integrate the functional aspects of the current methodologies with the architectural aspects. In order to illustrate our approach, in this paper we combine WebSA with the OO-H method to tackle the design of the well known J2EE Petstore specification.

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.

Current UML Profiles for Business Process Modelling realise a narrow focus of the process, and capture the process flow on a low level of detail. They do not provide a comprehensive coverage of theoretical aspects. In this work, we have designed a UML 2 Profile for Business Process Modelling that provides two complementary perspectives, focussing on the business process context (e.g. goals, measures, products, customers, etc.) as well as on the detailed business process flow. Therefore, the profile presents a business process in a very comprehensive way. It is tested with an example business process.