Reuse (Assume have source code, not a commercial product) Ariane 5. Therac-25. British AtC Expectation Significantly lower development costs and time. Amortize costs among all users or uses Assumptions

Formal design Reviews Associated with each of documentation phases Evaluate with respect to Customer requirements Prescribed standards and practices Contractual requirements

State Machine specifications Define behavior using states and transitions between states

Outline: Software Design Goals History of software design ideas Design principles Design methods Life belt or leg iron?(Budgen)

design: added inheritance, multiple inheritance, and polymorphism to ADT In process added complexity and increased some types of connectivity Lots of claimed advantages -- so far empirical evaluation is not supporting them well

法语语法课堂：法语常用并列从属连词一览 法语语法 aussi 因此 ou ... ou (bien) 或者 ...或者 car 因为 pourtant 然而 cependant 然而 puis 接着

Abstract Model Specifications Build an abstract model of required software behavior using mathematically defined(perhaps using axioms )types(e. g sets, relations) Define operations by showing effects of that operation on the model Specification includes Model

先看看一般的线性规划,即变量看作为实数.结果为

Requirements specification: A structured document that sets out the services the system is expected to provide Should be precise so that it can act as a contract between the system procurer and software developer and thus needs to be understandable by procurers and developers

一．简答题。 1.简述半导体材料的概念，特征及发展历史，并分别表明代表性的材料