（）analysis emphasizes the drawing of pictorial system models to document and validate both existing and/or proposed systems. Ultimately, the system models become the（）for designing and constructing an improved system.（）is such a technique. The emphasis in this technique is process-centereD. Systems analysts draw a series of process models called（）.（）is another such technique that integrates data and process concerns into constructs called objects.

Ultimately, the system models become the （） for designing and constructing an improved system.

A．image

B．picture

C．layout

D．blueprint

交流接触器上短路环的作用是什么？