Although formal methods for developing computersystems have been available for more than a decade, few have had significant impact in practice. A major barrier to their use is that software developers find formal met...
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ISBN:
(纸本)0780339800
Although formal methods for developing computersystems have been available for more than a decade, few have had significant impact in practice. A major barrier to their use is that software developers find formal methods difficult to understand and apply. One exception is a formal method called SCR for specifying computer system requirements which, due to its easy to use tabular notation and its demonstrated scalability, has already achieved some success in industry. Recently, a set of software tools, including a specification editor a consistency checker a simulator and a verifier, has been developed to support the SCR method [9, 11, 5]. this paper describes recent enhancements to the SCR tools: a new dependency graph browser which displays the dependencies among the variables in the specification, an improved consistency checker which produces detailed feedback about detected errors, and an assertion checker which checks application properties during simulation. To illustrate the tool enhancements, a simple automobile cruise control system is presented and analyzed.
software architecture has emerged as an important topic in softwareengineering. this paper examines what is new about the subject, and what is not, and what research trends we may expect in the future. We discuss the...
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software architecture has emerged as an important topic in softwareengineering. this paper examines what is new about the subject, and what is not, and what research trends we may expect in the future. We discuss the promise that work in the field holds, and organize the work into five predominant themes: selection, representation, evaluation, development, and recovery. Technology for the formal representation of architectures is examined in detail, along with notions of architectural styles and patterns. the paper begins by examining the range of meanings associated withthe term in order to provide a context for its treatment.
An early version of the Z Standard included the deductive system W for reasoning about Z specifications. Later versions contain a different deductive system. In this paper we sketch a proof that W is relatively sound ...
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ISBN:
(纸本)3540627170
An early version of the Z Standard included the deductive system W for reasoning about Z specifications. Later versions contain a different deductive system. In this paper we sketch a proof that W is relatively sound with respect to this new deductive system. We do this by demonstrating a semantic basis for a correspondence between the two systems, then showing that each of the inference rules of W can be simulated as derived rules in the new system. these new rules are presented as tactics over the the inference rules of the new deductive system.
the relational database model is currently the target of choice for the conversion of legacy softwarethat uses older models (such as indexed-sequential, hierarchical or network models). the relational model makes up ...
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the relational database model is currently the target of choice for the conversion of legacy softwarethat uses older models (such as indexed-sequential, hierarchical or network models). the relational model makes up for its lower efficiency by a greater expressive power and by optimization of queries, using indexes and other means. However, sophisticated analysis is required in order to take advantage of these features, since converting each database access operation separately does not use the greater expressive power of the target database and does not enable it to perform useful optimizations. By analyzing the behavior of the host program around the database access operations, it is possible to discover patterns such as filtering, joins and aggregative operations. It is then possible to remove those operations from the host program and re-implement them in the target database query language. this paper describes an automatic system, called MIDAS (MIgrator of Database Application systems), that performs high-quality reengineering of legacy database programs in this way. the results of MIDAS were found to be superior to those of the naive one-to-one translation in terms of readability, size, speed and network data traffic.
Mobile software objects are autonomous computational entities that travel in large-scale and widely-distributed heterogeneous systems, and whose functionality can be attached to diverse computing environments. An obje...
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Mobile software objects are autonomous computational entities that travel in large-scale and widely-distributed heterogeneous systems, and whose functionality can be attached to diverse computing environments. An object model that supports mobile objects should have special characteristics such as mutability of object's structure and semantics to facilitate adjustment to different environments, self-containment of objects to allow their migration as autonomous units, and extensive support for security. We discuss the requirements and design guidelines of such a model, and present MROM, a reflective model based on these guidelines. We also discuss MROM's implementation and present a component interoperability framework that was built on top of it, as an example application of the model.
Recent trend in high-performance computing focuses on networks of workstations (NOWs) as a way of realizing cost-effective parallel machines. this has been due to the availability of powerful wide-issue processors, hi...
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this paper stresses the importance of human interaction as a means of coordination and process guidance in system development. A metamodel for cooperative system development is proposed and relevant research (e.g., sp...
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this paper stresses the importance of human interaction as a means of coordination and process guidance in system development. A metamodel for cooperative system development is proposed and relevant research (e.g., speech act theory, design rationale) is presented within this framework the paper finally describes an architecture of a cooperative system development environment (SDE) realized as an extension of the softwareengineering platform MaestroII.
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