It is well known that the object data model has improved the expression power with regard to the relational model, supporting constructors such as multi-valued attributes or inheritance. However, there are still some ...
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ISBN:
(纸本)9608052122
It is well known that the object data model has improved the expression power with regard to the relational model, supporting constructors such as multi-valued attributes or inheritance. However, there are still some other important constructors, as ternary relationships or composite objects, that are neglected by most of the object data base systems, even by the object database standard, ODMG. Nevertheless, ternary relationships (and n-ary relationships, in general) are supported by almost every conceptual model due to their importance in modelling the real world. The problem is that n-ary relationships can only be used to define the conceptual schema, and so, it is necessary to invent a way of covering the gap between n-ary relationships allowed at a conceptual level and binary ones supported by the implementation models. To solve the mentioned problem, we propose an extension of the ODMG data model to support ternary relationships, based on the definition of a new collection type.
Extreme programming (XP) is a lightweight design method developed by Kent Beck, Ward Cunningham, and others. After notable successes, XP has been generating huge interest, and no small amount of controversy. Much of t...
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Extreme programming (XP) is a lightweight design method developed by Kent Beck, Ward Cunningham, and others. After notable successes, XP has been generating huge interest, and no small amount of controversy. Much of the interest stems from XP's pragmatic approach to development. Key practices include pair programming, writing tests upfront, frequent refactoring and rebuild, continuous integration and testing. Key principles incremental and iterative development, working with the simplest solution, cutting out extraneous documentation, and collective code ownership.
Legacy software systems present a high level of entropy combined with imprecise documentation. This makes their maintenance more difficult, more time consuming, and costlier. In order to address these issues, many org...
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Legacy software systems present a high level of entropy combined with imprecise documentation. This makes their maintenance more difficult, more time consuming, and costlier. In order to address these issues, many organizations have been migrating their legacy systems to emerging technologies. In this paper, we describe a computer-supported approach aimed at supporting the migration of procedural software systems to the object-oriented (OO) technology. Our approach is based on the automatic formation of concepts, and uses information extracted directly from code to identify objects. The approach tends, thus, to minimize the need for domain application experts.
To cope with the growing demands for simulation models of ever increasing complex industrial systems, the research community effort has been mainly focused in creating different software tools which simplify the model...
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To cope with the growing demands for simulation models of ever increasing complex industrial systems, the research community effort has been mainly focused in creating different software tools which simplify the modelling task. There is a recognized necessity of modelling tools supporting libraries of non-causal models which could be coupled in the same way as physical units are assembled in a system. This work presents an object-oriented Modelling language, PML, designed to support a modelling methodology where system models are described by linking system component models analogously as the system components are linked. This modelling language introduces a new modularization of physical knowledge, making a clear separation between the physical behaviour representation (declarative knowledge) and the computational aspects of model simulation (procedural knowledge).
The objectoriented paradigm is considered as one of the best approaches for systems development. There exists many models, techniques an tools developed following this paradigm. Nevertheless, most of the object-orien...
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The objectoriented paradigm is considered as one of the best approaches for systems development. There exists many models, techniques an tools developed following this paradigm. Nevertheless, most of the object-oriented techniques used in the development of systems does not take into account Human-Computer interaction issues. This is a very important aspect that must be tackled in order to correctly fulfil the user needs and requirements. The main purpose of this paper is to present an objectoriented approach for the integration of a user model in an objectoriented software production environment.
The object-oriented paradigm has been used extensively both in CASE tools for modeling and design of distributed real-time systems as well as in software tools for developing supervisory control systems. Supervisory t...
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The object-oriented paradigm has been used extensively both in CASE tools for modeling and design of distributed real-time systems as well as in software tools for developing supervisory control systems. Supervisory tools are very useful in the context of real-time industrial automation systems. Recent researches prove that the use of object-orientation paradigm in the development of these systems tend to produce better-structured and more reusable programs. This paper analyzes, using case studies, some of the widely used commercial tools for modeling and supervisory control generation. After that, some case studies using the analyzed tools are reported and finally a proposal of an integrated object-oriented environment for application development and monitoring is made. This work is part of an ongoing research project that has been developed at the Industrial Automation Lab. of Federal University of Rio Grande do Sul in Brazil.
Scientific visualization and simulation frameworks mostly use data/event flow mechanisms for simulation specification, control, and interactivity. Even though object orientation powerfully and elegantly models many ap...
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Scientific visualization and simulation frameworks mostly use data/event flow mechanisms for simulation specification, control, and interactivity. Even though object orientation powerfully and elegantly models many application domains, integration of OO libraries in such systems remains difficult. The elegance and simplicity of OO design gets lost in the integration phase, as most systems do not support combination of OO and dataflow concepts. We propose a general-purpose OO visualization and simulation system which addresses simulation design, control and interactivity by merging OO and dataflow modelling in a single abstraction. The system's advantages over similar ones are illustrated by a comprehensive set of examples.
In this work we present SmartBooks, a new approach to support framework instantiation based on the active cookbook concept, extended with the combination of the concept of user-tasks modeling and least commitment plan...
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In this work we present SmartBooks, a new approach to support framework instantiation based on the active cookbook concept, extended with the combination of the concept of user-tasks modeling and least commitment planning methods. Based on this technique, a tool can present to the developer the different high level activities that can be carried on when creating a new application from a framework, taking as basis the documentation provided by the designer through instantiation rules. For example, if the framework is on the accounting domain, some of the initial activities may be to create a new type of account, or to describe a new algorithm to calculate the tax rate. For each of these high level activities, there is a list of tasks that the user must carry out in order to complete the activity. When the user selects her next objective, the tool is able to build the sequence of tasks that have to be done to accomplish that objective;this list of tasks is called the instantiation plan, and the process of plan creation is named planning. In this paper we present the main characteristics of the planning approach and a example of the instantiation tool being developed.
One of the major reasons why finite element codes are difficult to keep clean and maintainable is that operations involving nodal information (and in particular, boundary conditions) show up in many sections of the pr...
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One of the major reasons why finite element codes are difficult to keep clean and maintainable is that operations involving nodal information (and in particular, boundary conditions) show up in many sections of the programs and in many different contexts. The matter is further complicated by the inadequacy of the unstructured procedural programming approach promoted by the Fortran language. This article addresses the management of linear constraints, and does so from an object-orientedprogramming viewpoint. Emphasis is laid on both the model design and the practical programming details.
This talk provides an insight into a variety of approaches to using visual programming tools. The talk introduces techniques that assist in the production of well designed, visually programmed software systems. Visual...
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This talk provides an insight into a variety of approaches to using visual programming tools. The talk introduces techniques that assist in the production of well designed, visually programmed software systems. Visual programming tools are very powerful but offer many paths that allow for the production of software that is difficult to maintain and interpret. The techniques introduced in this talk provide a basic framework for reducing the possibilities for developers to `shoot themselves in the foot'. IBM's VisualAge for Java is used as the basis for a variety of demonstrations showing these techniques in action.
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