Design And Development Of Agricultural Mechanization Production Expert System

Agricultural informationization construction is a important approach to solve problems about agriculture, ruralareas and peasantry, is a important way to construct new countrysides in China. As the main agricultural productivity, agricultural mechanization information was paid much attention. In resent years, agricultural machinery departments and operators have abilities to buy and use computers. Many information websites and correlative technology have been putting into use. All of these can enhance the level of agricultural mechanization information. Even though, the amount of the effective softwares for agricultural mechanization cannot satisfy the demand. Under these circumstances, to design and develop the effective software can promote the applying level and effect of agricultural mechanization technology, can promote the agricultural benefits, rise the peasantry's revenue, meanwhile, can promote agricultural economic development. The agricultural mechanization production expert system (AMPES) was designed and developed under the guidance of this thought and according to requests of the national "863" research plan and key projects of science and technology office of Heilongjiang province.To design and develop AMPES can satisfy the demand of the field of agricultural mechanizing production, but is also one of the important content of promoting agricultural information, developing digital agriculture and constructing new countryside. To discuss the basic theory, function and methods of designing and developing AMPES can lead the direction for designing and developing other expert system in the field of agricultural mechanizing production, can make a foundation for developing agricultural information. This research has important significance both in theory and practice.Researching and applying status and developing trends of expert systems in internal and external agricultural mechanization production field were studied on the basis of a mass of related literatures. Problems of agricultural mechanization expert systems applied in our country were pointed out. Concepts, the structure, characteristics and developing methods of the expert system were also detailedly discussed in the dissertation. Main contents of this research include general function design of AMPES, detailed design of modules, design of system databases and research of knowledge acquisition strategies, research of knowledge presentation and knowledge bases, design of management systems of databases and knowledge bases(DBMS/KBMS), research of inference strategies and design of inference engines, development of AMPES and so on.Combining theories with practice is one of the main principles of this research. System analyzing, general designing and modules detailedly designing were accomplished using the top to down method. Great deals of field knowledge had obtained by methods, such as in-depth investigations and studies, visiting field experts, designing and producing videos, and so on. Databases, knowledge bases of AMPES were designed according to hierarchy principle, and DBMS/KBMS were also designed and developed under the same principle. Knowledge acquisition (KA) mechanism had designed and developed which combined artificial KA, semiautomatic KA and automatic KA, and rule-based and semantic network methods were used to represent field knowledge after relative research. These research work effectively solve the bottleneck problem in expect system designing and developing course. On basis that, inference strategies had been analyzed and discussed in depth, forward reasoning and width-first search strategies were adopted, the case-base reasoning thought was also introduced to design inference engines. Conflicts could be resolved according to organizing order and explanation of knowledge with heuristic thought. Visual Basic 6.0 and Microsoft Access were adopted to develop Windows-based AMPES with the methods of prototyping, top-down and down to top.Main conclusions of the dissertation are as follows:(1) The general structure of AMPES was designed and the modules were compartmentalized on the basis of the analysis of the system function. Functions, operating thought and process of each modules were designed detailedly. Databases and knowledge bases were designed and their relation to system function is explicit. All of these are the foundation for the further development of AMPES.(2) AMPES was designed and realized for the first time, which includes three main functional modules which are mechanized technology process and operating criterions module, agricultural machinery selecting and equipping module and agricultural machinery maintenance module. AMPES can realize all functions under different area, different plant structure and sow manner.(3) Knowledge resources of AMPES were studied. Mass of character, photo and video materials were obtained after consulting and dealing mass of literatures, making many investigations in the practice. Field knowledge of AMPES is abundant and represented in variety type. videos about the some types of tractor technology maintenance were produced on the basis of scripts designed by the item group according to the system requirement and lots of photos were shoot. These videos and photos can make knowledge of AMPES more abundant, can enhance the knowledge presentation more intuitionistic and can make interfaces more friendly.(4) Knowledge acquisition (KA) of AMPES is one of the important researches of the dissertation. Semiautomatic KA and automatic KA mechanism were designed. The semiautomatic KA can be realized after knowledge engineers manage knowledge bases according to suggestions provided when experts operated AMPES. Knowledge can be added and renewed automatically after experts modify the consulted results directly and then saved in knowledge bases. Before using the system in each area, running the module can effectively avoid shortcomings of the inaccurate, incomplete knowledge and other disadvantages in the course of investigation. The credibility of the knowledge can be improved, the cycle of knowledge acquisition can be shortened and system efficiency and advisory effect can be improved under the KA strategies designed in the dissertation.(5) Database design and DBMS/KBMS are characteristics of the system. According to AMPES and the function requirements of each module, database were design in hierarchical, and relations between integrated databases and module databases, hierarchical structure, the quantity of tables in database and the specific structure of tables were designed detailedly. and DBMS/KBMS was designed and developed based on the three-layer databases, not only can make the conventional maintenance functions of database / knowledge base come true, but the module can automatically load all databases and knowledge bases of AMPES through the structure and content of its own databases. DBMS / KBMS code existing independently, can enhances the adaptability of the system, and simplifies code maintenance work.(6) According to the characteristics of field knowledge AMPES involves, rule-based method was adopted to express field knowledge such as technology process of mechanized operating and agricultural machinery selection. According to the characteristics of source technology process, the semantic network method was discussed and adopted to express the expert knowledge of the source technology process. Practical application of the system proved that knowledge representation methods designed are effective and practical, are propitious to realize system function.(7) Inference strategies of AMPES were studied. Rule-based inference engines were designed such as basic technology process inference engine, expert's agricultural machinery selection inference engine, ordinary user's agricultural machinery selection inference engine. Source technology process inference engine was designed, which is based on semantic network knowledge representing method. Meanwhile, case-base reasoning thought was also introduced to solve basic technology process inference problem appropriately, to improve the ability of automatic knowledge acquisition.(8) AMPES inference process was designed adopting forward reference and width-first search strategies. Conflicts can be resolved adopting the heuristic thought according to the knowledge organization order and the knowledge explanations. Some complicated inference problems, such as the technology process making and machinery selection, inference processes were realized by means of the strategies using the different inference engines in series in parallel. AMPES functions were realized effectively adopting these strategies.(9) According to the system demand, programs to calculate the amount of agricultural machinery were designed and realized. Functions, such as operating period compartmentalizing automatically, operating loads calculating in each operating period and operating load adjusting were also realized. At the same time, program for making farm machinery maintenance plan was also design and realized based on the calculation method.(10) AMPES can well adapt to changes of databases or knowledge bases because it was realized under the principle of independently programming. AMPES has more advantages according to the production tests in practice, such as perfect functions, friendly interfaces, rapid knowledge acquisition, convenient operation and maintenance, applicable knowledge representation strategies and effective inference engines designed reasonably and so on.