On the base of the traditional approaches for designing synchronous sequential circuits,a new approach for designing asynchronous sequential logic circuit is proposed in this paper where the trigger pulses can be directly obtained from sequential waveforms in sequential circuits,and the next state Karnaugh maps can be acomplished according to the state transformations caused by clock signals.

The realization method of three inner function modules of FPGA based on quartus Ⅱplatform is expatiated and the timing simulation waveform of these modules is given.

A method to recongnize valve variable table by timing diagram of control valve;

The polymorphism characteristic of the object-orient software is not considered in the research for sequence diagram metrics and the metrics are not exact.

The control principle of the Microgovernor is right described by sequence diagram for the first time.

Beehive Customer Management System used UML class diagram to build static model,used use case diagram to analyze requirement and used sequence diagram to build dynamic model.

Methods and skills using timing sequence diagram to proceed with PLC programming and program analysis were introduced,particularly the drawing of timing sequence and programming procedure in light with design requirement,and using timing sequence to know the procedure and analysis of programming.