30219210
Compositional Class Refinement in Object-Z
Object-Z allows coupling constraints between classes which, on the one hand, facilitate specification at a high level of abstraction, but, on the other hand, make class refinement non-compositional. The consequence of this is that refinement is not practical for large systems. This paper overcomes this limitation by introducing a methodology for compositional class refinement in Object-Z. The key step is an equivalence transformation of an arbitrary Object-Z specification to one in which introduced constraints prohibit non-compositional refinements. The methodology also allows the constraints which couple classes to be refined yielding an unrestricted approach to compositional class refinement.
2148830
Architectural design in object-Z
We present a process for introducing an object-oriented architecture into an abstract functional specification written in Object-Z. Since the design is derived from the specification, correctness concerns are addressed as pan of the design process. We base our approach on refactoring rules that apply to class structure, and use the rules to implement design patterns. As a motivating example, we introduce a user-interface design that follows the model-view-controller paradigm into an existing specification.
17770007
Encoding Object-Z in Isabelle/HOL
In this paper, we present a formalisation of the reference semantics of Object-Z in the higher-order logic (HOL) instantiation of the generic theorem prover Isabelle, Isabelle/HOL. This formalisation has the effect of both clarifying the semantics and providing the basis for a theorem prover for Object-Z. The work builds on an earlier encoding of a value semantics for object-oriented Z in Isabelle/HOL and a denotational semantics of Object-Z based on separating the internal and external effects of class methods.
594379
Extending W for Object-Z
This paper presents a logic for Object-Z which extends W, the logic for Z adopted as the basis of the deductive system in the Z Base Standard. The logic provides a basis on which tool support for reasoning about Object-Z specifications can be developed. It also formalises the intended meaning of Object-Z constructs and hence provides an abstract, axiomatic semantics of the language.
52867012
An Object-Oriented Development Framework for Z
This paper presents a framework for developing Z specifications in an object-oriented style. Within the framework, object-oriented concepts and design strategies are captured by the application of development operators. The framework also records the history of operator application enabling “classes” to be identified and, hence, the possibility of modular verification and refinement.
18518522
A Development Framework for Object-Oriented Specification and Refinement
This paper presents a language-independent framework for developing formal speciications in an intuitively object-oriented style. Within the framework, object-oriented concepts and design strategies are captured by the application of development operators. The operators, by eeec-tively hiding the technical details of how object-oriented concepts are captured in a given speci-cation language, allow the speciier to develop speciications in an intuitively object-oriented fashion. They also present a exible approach to object-oriented speciication as libraries of operators can be deened allowing many diierent dee-nitions of object-oriented features to be available. This enables a close mapping to be achieved between the speciication and the implementation in the chosen object-oriented programming language. The framework also records the history of operator application enabling \classes" and \modules" to be identiied in the resulting spec-iications and, hence, the possibility of modular veriication and reenement.
41530585
Computer Games Have Words, Too: Dialogue Conventions in Final Fantasy VII
42279258
A Unified Paradigm for Parallel Genetic Algorithms
Genetic Algorithms contain natural parallelism. There are two main approaches in parallelising GAs. The first one is parallelising individual functional components of a standard, sequential GA. The only difference with the sequential GA is in the computation speed. The second approach more closely resembles the real life simultaneous evolution of species, which is the central theme in GAs. Algorithms following this approach are still referred to as GAs but are different from Holland's standard GA. For these algorithms it is not the improvement in computation speed that is the driving factor, but the efficiency with which they search a given solution space. We describe a number of the most common parallel GA methods found in the literature and mention practical issues concerning their implementation in a Transputer based system. We go on to introduce the Unified Parallel GA system, based on our GA toolkit, GAmeter, which allows the user to select one or more of the GA methods described, by setting various parameters. Finally we present results for the Steiner tree Problem in Graphs (SPG).
1479807
The large-display user experience
The PC's increasing graphical-processing power is fueling a demand for larger and more capable display devices. Several operating systems have supported work with multiple displays for some time. This fact, coupled with graphic-card advancements has led to an increase in multiple monitor (multimon) use. Large displays offer users significant benefits and usability challenges. In this article the authors discuss those challenges along with novel techniques to address these issues.