Computer-mediated teaching can be very effective in enhancing students' understanding of concepts and increasing their involvement in the classroom. This paper presents an interactive visual simulation tool to ass...
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Computer-mediated teaching can be very effective in enhancing students' understanding of concepts and increasing their involvement in the classroom. This paper presents an interactive visual simulation tool to assist instructors in demonstrating power system stability phenomena. Power flow computations, used to initialise the simulation, are carried out using Mat lab, whereas the simulation is implemented using Simulink. The Graphical User Interface (GUI), which controls the whole program and is constructed using C#, provides the capability to change system parameters/operating points interactively. To further the grasp of stability notions and reinforce the sense of seamless photorealistic interaction with the simulation, visual animation illustrating the synchronous generator along with virtual analogue meters, represented as ActiveX controls to portray inherent machine variables, are constructed. Several test cases, which cover various power system stability events, are described and analysed.
We propose to use modal logic as a logic for coalgebras and discuss it in view of the work done on coalgebras as a semantics of object-oriented programming. Two approaches are taken: First, standard concepts of modal ...
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We propose to use modal logic as a logic for coalgebras and discuss it in view of the work done on coalgebras as a semantics of object-oriented programming. Two approaches are taken: First, standard concepts of modal logic are applied to coalgebras. For a certain kind of functor it is shown that the logic exactly captures the notion of bisimulation and a complete calculus is given. Examples of verifications of object properties are given. Second, we discuss the relationship of this approach with the coalgebraic logic of Moss (Coalgebraic logic, Ann. pure Appl. Logic 96 (1999) 277-317.). (C) 2001 Elsevier Science B.V. All rights reserved.
Given that corrective-maintenance costs already dominate the software life cycle and look set to increase significantly, reliability in the form of reducing such costs should be the most important software improvement...
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Given that corrective-maintenance costs already dominate the software life cycle and look set to increase significantly, reliability in the form of reducing such costs should be the most important software improvement goal. Yet the results are not promising when we review recent corrective-maintenance data for big systems in general and for OO in particular-possibly because of mismatches between the OO paradigm and how we think.
Emerald is a general-purpose language with aspects of traditional object-oriented languages, such as Smalltalk, and abstract data type languages, such as Modula-2 and Ada. It is strongly typed with a nontraditional ob...
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Emerald is a general-purpose language with aspects of traditional object-oriented languages, such as Smalltalk, and abstract data type languages, such as Modula-2 and Ada. It is strongly typed with a nontraditional object model and type system that emphasize abstract types, allow separation of typing and implementation, and provide the flexibility of polymorphism and subtyping with compile-time checking. This paper describes the Emerald language and its programming methodology. We give examples that demonstrate Emerald's features, and compare and contrast the Emerald approach to programming with the approaches used in other similar languages.
The burden of organizational learning surrounding software process innovations (SPIs)-and complex organizational technologies in general-creates a ''knowledge barrier'' that inhibits diffusion. Attewel...
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The burden of organizational learning surrounding software process innovations (SPIs)-and complex organizational technologies in general-creates a ''knowledge barrier'' that inhibits diffusion. Attewell (1992) has suggested that many organizations will defer adoption until knowledge barriers have been sufficiently lowered;however, this leaves open the question of which organizations should be more likely to innovate, even in face of high knowledge barriers. It is proposed here that organizations will innovate in the presence of knowledge barriers when the burden of organizational learning is effectively lower, either because much of the required know-how already exists within the organization, or because such knowledge can be acquired more easily or more economically. Specifically, it is hypothesized that organizations will have a greater propensity to initiate and sustain the assimilation of SPIs when they have a greater scale of activities over which learning costs can be spread (learning-related scale), more extensive existing knowledge related to the focal innovation (related knowledge), and a greater diversity of technical knowledge and activities (diversity). An empirical study using data on the assimilation of object-oriented programming languages (OOPLs) by 608 information technology organizations strongly confirmed the importance of the three hypothesized factors in explaining the assimilation of OOPLs.
An interesting and little documented problem is the influence of a design methodology on the program architecture. In this case study, we compared two design methodologies and their impact on both development process ...
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An interesting and little documented problem is the influence of a design methodology on the program architecture. In this case study, we compared two design methodologies and their impact on both development process and the resulting program architecture. The methodologies are object-based variants of refinement methodology and structured design, respectively. Both methodologies were applied to the same problem (a library system of less than 1000 lines of Ada code), and the results were compared. Substantial differences between the two resulting architectures are analysed and discussed.
Method schemas were proposed as a formal model of object-oriented languages. A method schema S is called consistent if, for each method invocation during the execution of S, a method definition to be bound to the invo...
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Method schemas were proposed as a formal model of object-oriented languages. A method schema S is called consistent if, for each method invocation during the execution of S, a method definition to be bound to the invoked method name is uniquely determined. However, the consistency testing problem is known to be undecidable in general. This paper presents an algorithm which analyzes the consistency of a given method schema. The algorithm decides the consistency problem in polynomial time for monadic method schemas. We also provide an incremental algorithm for testing consistency after updates of a method schema.
An architecture for an expert-system shell that mixes declarative nd procedural knowledge, overcoming a major problem of conventional shells, is presented. The prototype shell uses structured knowledge representations...
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An architecture for an expert-system shell that mixes declarative nd procedural knowledge, overcoming a major problem of conventional shells, is presented. The prototype shell uses structured knowledge representations and its built-in database interface not only allows automatic extraction of data from a database management system but also provides a fuzzy database query facility. The shell's object-oriented approach to knowledge representation supports data and knowledge acquisition and management. Another feature is encapsulation which prevents object manipulation except by defined operations. A comparison of representation methods and two case studies showing System X-I's power and flexibility are included
Design plays a key role in the development of software. The quality of design is crucial and is a fundamental decision element in assessing the software product. The early availability of design quality evaluation pro...
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Design plays a key role in the development of software. The quality of design is crucial and is a fundamental decision element in assessing the software product. The early availability of design quality evaluation provides a better way to decide the quality of the final product. This avoids presumption in the quality evaluation process. Hence Software Metrics provide a valuable and objective insight of enhancing each of the software quality characteristics. This paper proposes a quality model to assess the design phase of any object-oriented system based on the works of Chidamber, Kemrer and Basili and suggests two new metrices. Teh research focuses on analyzing a set of metrices, which has direct influence on the quality of the software and creating a metrices tool based on Java that is carried out on a set of real world projects designed using Unified Modeling Language, which are used as test cases. These metrices and models are proposed to add more quality information in refining any object-oriented system during the early stages of design itself.
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