This paper presents the Maestro tools for rapid development of reliable, interoperable, object-oriented distributed applications. The tools include IIOP-conformant object Request Broker with an open architecture suppo...
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This paper presents the Maestro tools for rapid development of reliable, interoperable, object-oriented distributed applications. The tools include IIOP-conformant object Request Broker with an open architecture supporting multiple execution styles/request processing policies. The Replicated Updates execution style implemented in Maestro can be used to add reliability/high availability properties to client/server CORBA applications in settings where it is not feasible to make any modifications at the client side. Measurements over Horus group communication system have shown that Maestro offers good performance with little overhead for reliability. (C) 1998 John Wiley & Sons, Inc.
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.
Experience in industry suggests that reuse does not happen without retraining. However, since reuse is meant to simplify programming, this paper argues the case for re-ordering a traditional data structures and algori...
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Experience in industry suggests that reuse does not happen without retraining. However, since reuse is meant to simplify programming, this paper argues the case for re-ordering a traditional data structures and algorithms course, using an object-oriented language, so that it starts from abstraction and reuse, and postpones coding from scratch as far as possible. The intention is that reuse should be learnt before other strategies, so coding from scratch does not have to be unlearnt before reuse seems natural. The paper presents experience with a restructured abstraction;fir st course, and proposes that an essential tool for such a strategy is a set of scaled-down libraries and frameworks, designed for teaching. Compared with a Modula-2-based course and an earlier C++-based course in which concepts were presented in a different order, more ground was covered, without a major change in the students' results (grades). (C) 1998 Elsevier Science Ltd. All rights reserved.
Component programming models offer rapid construction for complex distributed applications, without recompiling and relinking code. This survey of the theory and design of component-based software illustrates their us...
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Component programming models offer rapid construction for complex distributed applications, without recompiling and relinking code. This survey of the theory and design of component-based software illustrates their use and utility with a prototype system for manipulating and solving large, sparse systems of equations.
This paper presents an object-oriented distributed language, called PVOOL, that is a good tool for developing real distributed applications. PVOOL is based on active objects called pv-units and concurrent message pass...
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This paper presents an object-oriented distributed language, called PVOOL, that is a good tool for developing real distributed applications. PVOOL is based on active objects called pv-units and concurrent message passing among them. The main feature of PVOOL is the possibility to coordinate the activity of different pv_units through virtual circuits. Virtual circuits are objects that indicate what are the operations to be performed, what are the pv_units that must do them, and what is the order in which they must be done to give a certain task. Virtual circuits can be dynamically created by pv_units and so this distributed object-oriented system can change its behavior during its life. PVOOL takes advantage of PVM procedures to perform objects distribution and message exchange, without explicitly writing low-level code. The use of PVM allows an easily distribution of a program, that is of its objects, on a heterogeneous network of parallel and serial computers. In particular, the paper describes how the features offered by PVOOL were useful to implement a flexible environment for the development of computer vision applications. (C) 1998 Elsevier Science inc.
This paper presents a high level class library for dynamic world modelling. Any virtual physical world is considered here as a body system, i.e. a set of interrelated bodies. This library offers not only classes of pr...
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This paper presents a high level class library for dynamic world modelling. Any virtual physical world is considered here as a body system, i.e. a set of interrelated bodies. This library offers not only classes of primitive bodies and a hierarchy of inter-body constraints, but also a hierarchy of basic body system classes. Building a specific dynamic world and its parts consists of sub-classing and instantiating these classes. This library facilitates the construction of dynamic virtual worlds by offering a systematic and extensible programming interface. The body system model provides also some hints to future evolution of VRML and a framework for dynamic world modelling in Java programming language. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
In the present paper, we have proposed and applied a new object-oriented modeling and programming paradigm to the CFD problems, especially to the Navier-Stokes flow problems. The modeling procedures are integrated and...
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In the present paper, we have proposed and applied a new object-oriented modeling and programming paradigm to the CFD problems, especially to the Navier-Stokes flow problems. The modeling procedures are integrated and reconstructed according to the object-Based (OB) modeling and programming paradigm, which is one of the object-oriented paradigms. Throughout this integrated OB modeling and programming process,an object-oriented (or OB), flexible Navier-Stokes numerical simulation system has newly been developed and applied to the actual flow simulation problems. We have also developed the integrated support environments, for example, the body shape definition GUI tool, the computing nodes handling tool, the visualization system, and the object-Based Repository (OBR), etc.. From the simulation results of this system we have verified that (1) the OB modeling and programming methodology, (2) its actually developed fluid flow simulation system with the aid of the integrated support environments, are very valuable, flexible and useful for the domain users in the CFD field. This system powerfully helps the CFD simulation user to search and discover the essentials of the simulated fluid flow world in detail without any tedious troubles and with the satisfactory simulation controls. (C) 1998 Elsevier Science Ltd. All rights reserved.
Wiener agrees with Hatton that OO does not match the way we normally think. He goes on to say, however, that this is true of programming in any language using any paradigm. Given this, he argues, it is essential that ...
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Wiener agrees with Hatton that OO does not match the way we normally think. He goes on to say, however, that this is true of programming in any language using any paradigm. Given this, he argues, it is essential that we use good principles, good ideas, and good languages. Further, to compare OO and non-OO implementations, researchers should look at a true OO language-and that isn't C++.
object-oriented programs are simpler to implement and maintain than those using traditional programming methods. At the same time, object-oriented programs create and destroy objects, incurring overhead costs. They al...
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object-oriented programs are simpler to implement and maintain than those using traditional programming methods. At the same time, object-oriented programs create and destroy objects, incurring overhead costs. They also cause unnamed temporary objects of the same type to be created in the scope of the calling routine. Both of these factors affect the performance of object-oriented programs compared to procedural programs. For these reasons, programmers view object-orientedprogramming as wasteful compared to procedural programming. When runtime efficiency is important, developers have a legitimate reason to reject OOP. In this article, the authors propose to improve the efficiency of the underlying implementation by reusing temporaries. They report experimental results showing large speedups using this method.
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