在oop walid Al-Ahmad中设计概念模型的框架(含外文出处)

摘要：
在面向对象编程中，有一些语言结构和机制提供对概念模型的支持： liskov替代原则，依据合同的Meyer程序， the Beta的内部结构， C ＃和Java接口 ，从所有集合中分离出子类型的层次作为timor和sather 。所有这些机制和结构是强大而有用的工具，在面向对象编程中，它们能够增强继承机制的概念建模的特性。它们的目的是为了确保被继承联系的类的语义兼容性。当它们被单独应用时，这些机制可建立正确的、可容易理解的、可使用的、可扩展的继承层次。这篇文章论述了不同的机制，并研究了它们之间的相互作用。这将证明，通过使用这些工具概念建模是否能够成功建立。这也将显示出这些工具之间的相互作用可能导致矛盾，并有可能阻止合理的继承关系。在语言水平上，概念建模机制的框架，将更好地支持概念建模。
关键词：合同程序，liskov替代原则，继承，概念建模。

A dual ASP “durable storage” commercial service
Abstract
In this article we will describe a commercial service that will use distributed resources, such as storage or bandwidth, in a cooperative effort. We name this service “durable storage”. This service is able to guarantee the existence of the data it contains in “any circumstance” at “any time”. Although the solution is based on a P2P paradigm, we use a centralized approach that matches the commercial side of the service. We have designed the system with anonymity, confidentiality and security in mind. The ISP, or service provider, will not only assure several of the main functions, such as authentication or directory maintenance, but constitutes as well the only billing point for every user. We will describe the architecture or the service and the implementation of the prototype which is a dual stack IPv4/IPv6 application. Finally we will point out that the solution is not only IPv6 compatible, but it could clearly benefit from an IPv6 only version.