(铁路路基CAD软件系统的设计与实现)

Introduction in Chinese,1.What is a Description Logic?,2. technical contents,3.Relationship with other Logics,4.Reasoning Techniques,5.Conclusions,Design & Realization of CAD Software System for Railway Roadbed,(,铁路路基,CAD,软件系统的设计与实现,),200412110020,Xie Baiyi,18th Apr. 05,Outline,Instruction,technical contents,Software applications,Future Work: the study of Expert system for Roadbed CAD,Roadbed is an important part of railway infrastructure. It has a function to bear the train,s load and resist the damage from environment and other sources. Roadbed design includes three main parts, i.e. the design of slope reinforcement and protection, the design of soft clay ground treatment, and the design of drain system. The roadbed design has a close relationship with the conditions of terrain and geology. For the conditions of terrain and geological are various and changeable, the design for roadbed is various and difficult. This paper introduces a model to simulate the design of roadbed and discusses how to realize it by using Object Oriented Programming technology and ObjectARX.,1.,Instruction,2. technical contents,2.1Roadbed design model,2.2Input data treatment,2.3CAD treatment,2.4Quantity calculation,2.1Roadbed design model,To build an overall roadbed CAD model, there are two key considerations.,The first is the problem reduction principle, i.e. for roadbed design is very difficult in a whole, so I separate it into some components. Each component can be computerized and must be relatively functional independent. So we can use Object Oriented Programming technology to formalize them. And we build a big class of roadbed with aggregating the all component classes. It contains all component classes as its,component base,. The function of the aggregating class of roadbed is to form different performance, i.e. different roadbed design scheme, by choosing one or more different component classes from component base.,2.1Roadbed design model,The second is multiple level parameterized controls. The railroad is a strip structure. And it,s changeable in roadbed design conditions.,The roadbed design has some common features, so we can abstract some overall parameters from it.,2.1Roadbed design model,Secondly the components keep relatively stability in a scope. Moreover, we introduce some control parameters in components according to unification principle, so they can have same parameterized control but perform differently according to different roadbed design conditions.,We make every component have a property of subsections and every subsection has subsection parameters.,So it forms the second level of parameterized control.,2.1Roadbed design model,Finally, in every subsection of a component, there still exist some special features that cannot be completely expressed by subsection parameterized control, especially in a situation that some users are unwilling to have the component to divide into more subsections. So we take the cross-section parameterized control into model. The cross-sections are contained by the component subsection. They can have same or different parameters with subsection they belong to according to real design condition.,2.1Roadbed design model,The software system structure can be expressed as following diagram.,Output,Input data treatment,CAD treatment,Soft clay ground treatment,Drain system,Quantity calculation,Slope reinforcement and protection,2.2Input data treatment,They are the roadbed design,s input part. The key consideration is how they will be obtained more efficiently and what way they will be stored.,2.2Input data treatment,Among these, how to get the geological data efficiently and precisely is a key problem. So we build an,engineering geological automatic stratum connecting model, which contains a simple intelligence reasoning to form an automatic stratum connecting, to give facilities for getting the roadbed,s geological data automatically.,2.3CAD treatment,the design of slope reinforcement and protection,It contains,cross-section design, and,elevation design, i.e. the slope plane design to show exactly the slope design, which shows slope design in detail but ignores other part. There are many,slope treatments, so the software must deal with all these treatments. The cross-section design is the root design. After having finished treatment of cross-section design, the elevation design data are automatically acquired, which can be used to do the elevation design. So the elevation design can be automatically fulfilled in this system.,For elevation design is a more detail design for slope, so we require that its design result can be used to optimize the cross-section design. The software has a method to deal with it, by modifying the component parameters according to elevation result. It is not tough, for all cross section and elevation design result data are all in the same subsection.,2.3CAD treatment,the design of soft clay ground treatment,There are many kinds of,ground treatment,methods. We have analyzed them and draw out some components from it. In soft clay ground design, it contains not only cross-section design, but also soft clay ground treatment,horizontal plane design and engineering geological vertical section design,of soft clay ground treatment. (We merge the soft clay ground horizontal plane parameterized control data into cross-section design data, so we can ensure their consistence).,In order to treat engineering geological vertical section design, we build an,engineering geological automatic stratum connecting model, which has been mentioned in the data treatment part.,2.3CAD treatment,the design for drain system,Roadbed,drain system design,is a very important aspect, for most damages of roadbed are caused by water, directly or indirectly. This software builds a procedure which has some kind of intelligent treatment for drain system, which can automatically locate the horizontal and vertical position, make the water flow along a smooth drain gradient. After being treated automatically, if users want to change design to their own desire, they can do it freely.,2.4Quantity calculation,The calculation for quantity of the materials that used in roadbed is very import, for we must use it to evaluate the economical invest and prepare the materials when constructing the railroad. The software automatically calculates the quantity in components,CAD process with some intelligence.,2.4Quantity calculation,Beside automatic quantity calculation, the name of quantity can be modified flexibly, which is necessary when the materials have changed. This software has a database to manage the quantity names, which produces a quantity code for every quantity item. In the software, all quantity items are identified as a code.,We still can add some new quantity items to the design automatically by giving the new name and a formula of added quantity item.,2.4Quantity calculation,The quantities must be,summed up,and, furthermore, it is required that the quantities and their sum steps must be output in report forms. We can write code to deal with it. But we have an easier way to do it by means of putting them,to EXCEL worksheets,. We know that EXCEL software has a function to provide a service for automation. We can use this feature to fill all reports to EXCEL.,3Software applications,From 1998, the software has been applied in almost all railway line,s roadbed design we took charge in, from primary design stage to detail-drawing design stage. It had a usage rate from 66% when beginning to over 95% latterly. The famous Beijing-Shanghai High-speed railway line and all other railway lines used it to fulfill the design. Corresponded with practice,s needs, it has made three times version conversion and upgrade, and now it still in the process of improving. In Apr. 7th 2001, the software system passed the provincial authentication and we were grad to know an authoritative evaluation that this software system had reached the country,s highest level in its field.,4Discussion for expert system,This railway roadbed CAD software system implements the railway roadbed,s automatic design by producing a model to simulate the process of real world design. It used the Object Oriented and CAD Programming technology, and other technologies. It has been used in the highway roadbed design. By doing some conversion, it can be applied to other relevant fields of rock and soil engineering. It has improved the productive efficiency greatly and gained a great profit to its application field.,4Discussion for expert system,But if we want to do better, we must have some more ideas. We know that CAD software must be combined with MIS, and we have been doing this work and make MIS be the base of the system and CAD the core. But it is not enough. To have a fundamentally changing, we must have an expert system, which provide expert quality advice, diagnoses and recommendations given real world problems.,4Discussion for expert system,As to the roadbed design field, for there are numerous commercial expert system shells. We must find a way to separate domain specific knowledge from more general purpose reasoning and representation techniques.,To cultivate this expert system, we have so much to learn, especially the knowledge of knowledge engineering. But it has encouraged us that expert systems have been used to solve a wide range of problems in engineering domains which involve design. I have confident to realize it in a not far future.,Thank you,End,