计算机英语 刘艺 王春生 第4版Unit 10B.pptVIP

Antivirus Software; master useful terms understand the approaches to combat computer viruses ;terms or phrases ;terms or phrases ;I. Introduction;回顾;II. Approaches;II. Approaches; Although the dictionary approach can effectively contain virus outbreaks in the right circumstances, virus authors have tried to stay a step ahead of such software by writing oligomorphic, polymorphic and more recently metamorphic viruses, which encrypt parts of themselves or otherwise modify themselves as a method of disguise, so as to not match the viruss signature in the dictionary.;II. Approaches;Dictionary;; Additinally, computer applications that are unwanted by the system administrator are prevented from executing since they are not on the whitelist. Since modern enterprise organizations have large quantities of trusted applications, the limitations of adopting this technique rests with the system administrators ability to properly inventory and maintain the whitelist of trusted applications. As such,viable implementations of this technique include tools for automating the inventory and whitelist maintenance processes.;II. Approaches;II. Approaches;II. Approaches;Suspicious Behavior;This problem has worsened since 1997, since many more non-malicious program designs came to modify other .exe files without regard to this false positive issue. 自1997年以来，因为有更多的非恶意的程序设计用来修改其他exe执行文件而不考虑假的病毒警报问题，这个问题已经恶化。;II. Approaches;Other Approaches;Other Approaches;Other Approaches;Other Approaches;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;III. Issues of Concern;IV. Effectiveness;;过去分词作定语， 过去分词作定语，在语态上表被动，在时间上表示动作已经发生或完成；与它所修饰的名词有逻辑（意义）上的动宾关系。 单个的过去分词作定语时，前置，即位于它所修饰的名词或代词前面。如： a risen sun 已升起的太阳 an organized trip 有组织的旅行 过去分词短语作定语时，后置。即位于它所修饰的名词或代词后面。如： a school built for orphans 为孤儿专建的学校;分词作定语时有下面