With the move to distributed systems and an increasing emphasis on the use of object-orientation for new system design, effective distribution of object-oriented applications is becoming an important concern for desig...
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With the move to distributed systems and an increasing emphasis on the use of object-orientation for new system design, effective distribution of object-oriented applications is becoming an important concern for designers. Early research in this area has focused on object-clustering schemes for shared memory configurations that have limited value to business applications, which must be distributed over loosely coupled networks. These applications also exhibit the properties of simpler structural relationships and a large number of instances, demanding approaches closer to fragmentation and allocation instead of clustering. This paper develops an approach to distribution of object-oriented applications over geographically dispersed sites in loosely coupled networks-taking account of concerns such as encapsulation, inheritance, messaging, and implicit joins. The approach consists of two phases. First, we develop a scheme for generating class fragments, which ensures that encapsulation is not violated and inheritance is not stretched across sites. Second, considering the message-intensive operation of object-oriented systems, we devise models for allocation of class fragments to sites that minimize inter-site traffic. A nonarbitrary procedure to compile traffic volume estimates exploiting the notion of implicit joins in object-oriented applications provides the natural linkage between the two phases. A research prototype was implemented to establish feasibility of the proposals. We demonstrate usefulness of the approach by its application for distribution of a real-world information system.
With the popularity of English across the world, demands grow for English of daily use. By reviewing the English learning methods and its patterns at home and abroad, this paper conducted a major analysis on the statu...
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With the popularity of English across the world, demands grow for English of daily use. By reviewing the English learning methods and its patterns at home and abroad, this paper conducted a major analysis on the status of English self-learning in China. On this basis, a computer network platform based English learning system was designed and realized by using software engineering approaches, whose development techniques are discussed subsequently. Finally, the performance and safety of the online English learning platform are tested. The test results show that the system is effective in improving students' ability to learn English by themselves.
Utility companies are shifting their maintenance strategies from corrective or time-based to risk based. Meanwhile, the asset datasets which support these strategies are being migrated from spreadsheets to databases. ...
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ISBN:
(纸本)9781467310192
Utility companies are shifting their maintenance strategies from corrective or time-based to risk based. Meanwhile, the asset datasets which support these strategies are being migrated from spreadsheets to databases. As a first necessary step of this migration, the authors analyzes the requirements from risk based maintenance strategies add to the maintenance management software systems, through extending the use cases of existing software products. The main contribution and characteristic of these extensions is to provide "flexible information sharing", i.e. facilitate the growing demands to exchange asset data among stakeholders for the future development of asset management systems.
To solve the difficulties in training on ship,a new simulator was developed by importing,digesting and recreating the Kongsberg *** model-based and object-oriented design following by modular programming method,the wh...
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ISBN:
(纸本)9781510805750
To solve the difficulties in training on ship,a new simulator was developed by importing,digesting and recreating the Kongsberg *** model-based and object-oriented design following by modular programming method,the whole set of system is developed by VB under Windows platforms and Sequence Query Language(SQL) Server *** has functions of liquid cargo handling simulation training,training results evaluation,operation management,real-time monitoring,and simulation data *** than 20 kinds of mathematical model were established,including the model of the temperature,pressure,precooling,liquid level,pump,liquid cargo tank and so *** the experimental test,the training of loading and unloading simulation operation has been completely realized and the result has successfully fulfilled practical *** work laid the foundation of the follow-up improvement and development for LNG carrier liquid cargo handling simulator.
With the move to distributed systems and an increasing emphasis on the use of object-orientation for new system design, effective distribution of object-oriented applications is becoming an important concern for desig...
详细信息
With the move to distributed systems and an increasing emphasis on the use of object-orientation for new system design, effective distribution of object-oriented applications is becoming an important concern for designers. Early research in this area has focused on object-clustering schemes for shared memory configurations that have limited value to business applications, which must be distributed over loosely coupled networks. These applications also exhibit the properties of simpler structural relationships and a large number of instances, demanding approaches closer to fragmentation and allocation instead of clustering. This paper develops an approach to distribution of object-oriented applications over geographically dispersed sites in loosely coupled networks-taking account of concerns such as encapsulation, inheritance, messaging, and implicit joins. The approach consists of two phases. First, we develop a scheme for generating class fragments, which ensures that encapsulation is not violated and inheritance is not stretched across sites. Second, considering the message-intensive operation of object-oriented systems, we devise models for allocation of class fragments to sites that minimize inter-site traffic. A nonarbitrary procedure to compile traffic volume estimates exploiting the notion of implicit joins in object-oriented applications provides the natural linkage between the two phases. A research prototype was implemented to establish feasibility of the proposals. We demonstrate usefulness of the approach by its application for distribution of a real-world information system.
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