Design and Optimization of Extensible Vector Graphics Markup Language and its Integration with Knowledge-based System
ZHANG Guo gang, WANG Jian hua, WU An bo(School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049)
Electrical drawing is an important engineering language to describe the structure, principle, function and etc. of electrical system and equipment. This paper proposes an XML based language, XvgML, which is designed to represent the electrical drawings. The XvgML definition includes three steps: establishing the object model, defining and naming the elements and properties, and compiling the DTD document. Two kinds of method can be applied to optimize XvgML. One is to remove the property equal to the default value which is set in DTD document, the other uses LZW algorithm to compress the XvgML document. These two methods make an obvious effect to reduce its storage and promote application performance. XvgML is composed of geometry elements and electrical elements so that it is able to model electrical systems and equipments. It is more powerful than other vector graphics languages with only geometry elements. With inherited from XML, XvgML is well formed, simple and extensible, and can be well integrated with knowledge based system. An example of electrical circuit layout Intelligent CAD has been build, it benefits from using XvgML as the intermediate language between the CAD engine and expert system. In short, XvgML will be widely used as an electrical graphic format in Web based Intelligent CAD system, Web based quoting system, or as an intersystem data exchanging medium.