This paper describes the development of an optimal management system of stored grain in GIS environment ,which provides a new method for designing and implementing an advanced stored grain management system for farmers and specialists related to stored grain management. In the project, the general principle and basic method of designing the system were developed. The system consisted of key subsystems such as expert system, simulation models and basic GIS environment. Especially, Esri�s advanced GIS software ARCVIEW 2.1 was used to integrate all subsystems into the final system. A number of simulation models were developed using the numeric or graphic variable methods under ARCVIEW environment, which are used to monitor and describe some dangerous status such as dangerous temperature and moisture values in stored grain. A layered architecture model was developed to describe architecture of the stored management system and to guide the system design and implementation. An ARCVIEW real world based on the architecture was built to complete final O-O implementation of the system. Some key techniques such as design of various basic models, their each other relationship analysis and how to integrate them under ARCVIEW environment were also discussed in detail. The performance of prototype of this system is very satisfactory. In current time, we have been testing and refining the prototype functions in order to constant larger practical application system based on it.
1. INTRODUCTION Scientific management of stored grain is one of the most parts that consist of grain production system in modern agricultural production. In recent several years, the number of stored grain loss during the store period in the world has been increasing due to the very poor or no scientific management of stored grain, especially in most of developing countries. Thus, it is really necessary to construct an advanced management system of stored grains with some current advanced techniques of information science for implementing their scientific management in order to increase modern level of grain production. In fact, because of the possible large size of grain shortage in the world extent in next century, the constructions of advanced stored grain facilities and related management systems will become a more and more problem in the future. However, how to design and construct the management system has been being a very complex and important problem in the researches on stored grain management engineering. In past many years, a number of technical papers had discussed deeply the problems how to design and implement a number of stored grain management systems and provided many usual practical experiences and outcomes. But, we consider that those outcomes lack a scientific system method to describe and solve this problem, so that so far is how to implement the scientific management of stored grain still a very complex and difficult problem. In general, this stored grain management belongs to a problem of large complex system management about optimal control and decision that involves other problems about how to control and manage many complex objectives. Thus, there are a number of factors to influence the design and implementation of this system, which include the stored grain kind and quality, stored grain facilities, environmental temperature and moisture, and various possible pests, etc.. Main objective of this management is to control the stored grain environment using natural and artificial aeration means to destroy any possible conditions resulting in any possible stored grain disasters in order to assure that temperature and moisture of stored grain are in the safety range. In general, an advanced stored grain management system based on a green control rule (no chemical means) must complete two basic tasks as follows. (1)Estimate or predict the temperature and moisture values of any position in a stored grain entity in any necessary time. (2)Manage or control various possible dangerous states of the temperature and moisture in the entity for storing grain because they could result in various possible stored grain disasters. One of most important tasks completed by the advanced grain management system is to precisely predict the temperature and moisture in the grain of all stored grain entities of grain warehouses distributed on a very large geographical areas. The previous or past mathematical models developed for completing the task used mainly a linear regression concept to predict the temperature and moisture and did not consider the strong influence from geographic region factor or information to the prediction. Further, because those models used only a few factors effecting on the temperature and moisture as their input parameters, and considered that all physical positions in a stored grain entity had the same temperature and moisture value, so that their precision and practical value in practical application were not satisfactory. However, in recent several years, some mathematical models based on the analysis of differential equation and vector field had be developed to predict the temperature and moisture on any space position in stored grain entity on the condition that the stored grain entity was investigated as a complex temperature and moisture fields. Some of those models could be used to predict the temperature and moisture on any spatial point in the entity, whose precision was basically satisfactory. Otherwise, those models have also some common and obvious disadvantages such as large computation cost, vague computation results and obvious difficulty to determine various dangerous states. Further, the main reason resulting in the above disadvantages is really that those models belong usually to one dimension numeric computations model. However, our research shown that those models must be reasonably improved to overcome their disadvantages. On the other hand, a modeling method based on graphic variables had be successfully developed and be used to design and implement the mathematical model used in our advanced stored grain management system. This paper presented mainly our new method for designing and implementing an optimal management system of stored grain in GIS environment and our new advances in the research of stored grain management. First, the general principle and basic method of designing basic model of the management system were discussed. Secondly, the basic GIS environment based on ARCVIEW 2.1 and how to implement the above basic model in it were respectively investigated. Thirdly, some key techniques which were used to implement the management model in the GIS environment were discussed, which includes how to integrate the optimal system from several subsystems. 2. MANAGEMENT SYSTEM ARCHITECTURE. The architecture of optimal stored grain management system can be described by a seven-layer architecture model shown in Fig. 1. The layer of basic facilities
describes the function, geographic position, performance and quality of basic facilities for the management of stored grain. The layer of stored grain kinds describes all information for management of kinds of stored grain, which includes the number of kinds of stored grain and the characters of stored grain in the facilities. The third layer is weather environment layer, which is used to implement weather environment management of stored grain. In the management, a number of historical and current weather data are used to analyze the weather environment of regions where stored grain facilities are built and managed. The main task of decision data layer is to generate a number of basic data form service of the low three layers for supporting operation of decision models in its high layer. The decision layer consists of a number of basic decision models to make basic optimal management decisions of stored grain. The management layer is used to define various different integrated management decisions for different stored grain facilities according to practical requirement of those facilities and with the help of various basic decision services provided by decision layer. The application layer is mainly to support various different applications of optimal stored grain management in order to suite the needs from various different users. In the layered architecture, the lower layer provides always its service for its higher layer, the higher layer uses the service from its lower layer. Our experiences have shown that to construct the layered architecture model is a very effective method for designing and implementing a high quality GIS application system. 3. ARCHITECTURE IMPLEMENTATION The above layered model can be further divided into three different subsystems such as basic management, advanced management and application subsystems. The basic management subsystem provides mainly some raw management data about stored grain facilities, kinds and weather environment and some simple management suggestion for the management system users. The subsystem structure and relationship with GIS environment is shown in Fig. 2. Obviously,
operation of basic management subsystem is supported mainly by GIS environment. This is because three management tasks of the subsystem have very close relationship with geographic information. For example, a number of data used to describe weather environment, managed grain kinds and various basic facilities about stored grain have very obvious geographic characters. Thus, this subsystem is finally implemented in GIS environment. Otherwise, this subsystem provides also various services for advanced management subsystem with the exchange of basic management data between them under custom/server (c/s) mode. Three layers on basic management subsystem construct the advanced management subsystem. This management subsystem is mainly used to complete all optimal control and management works about stored grain according to basic management data from its next subsystem. A typical advanced management subsystem is shown in Fig. 3. The decision data layer makes mainly use of various simulations models
further generate a number of support data that are used by decision models to provide optimal control and management decision for stored grain. These models can further be divided into two classes such as numeric simulation models and graphic simulation models in order to suite different requirements from various different decision models. In fact, the numeric models are very common and support mainly operation of numeric decision models. However, graphic simulation models are used to provide graphic decision data for our new graphic decision models in the decision layer. The operation of graphic simulation model was implemented on GIS processor based on GIS environment with the help of complex operations among various graphic coverages about the data from basic management subsystem. In the decision layer, an expert system is used to support operation of those decision models, which is a rule-based system containing an inference engine, a file maintenance system for the decision model input data, a database system for the knowledge base, and a interface- driven system for interactions of higher and lower layers. The inference engine applies rules to set up weather and management practices, to execute a special decision program, and to interpret the operation results of decision models to make recommendations on the control and management of temperature, moisture and pest of stored grain. In the expert system, the rule-base is based on some excellent expert experiences and ability to run decision models, interprets their results for higher layer and make the layer produce various effective management decision. There are a number of application-oriented management models in the management layer, which are designed and implemented in order to flexibly satisfy the requirement of various typical stored grain facilities. The application subsystem includes only the application layer, which is shown in Fig. 4. There are three classes of models to support the subsystem operation. The
local application models describe various different requirements and application means of local users when they use the optimal management system of stored grain. On the other band, the remote application models provide a number of means to support those remote users to use the management system though computer network or any other telecommunication network. The models for testing system functions are designed and implemented for determining whether the management system can complete its predetermined various operations. Otherwise, those models assure that the management system can complete its normal operation. In fact, our practices have shown that the layered architecture model and the division of those subsystem as well as the implementation of those subsystems are very reasonable for designing and implementing the optimal management system of stored grain in GIS environment. 4. IMPLEMENTATION BASED ON ARCVIEW 2.1 According to the above discussion, the optimal management of stored grain is a very complex system related closely to geographic information and includes several relative alone subsystems. Thus, how to integrate those subsystems become really another key problem to determine whether the management system can obtain its success in practical applications. We selected Esri�s advanced GIS software ARCVIEW 2.1 with Avenue as a basic frame work to implement the above integration. The relationship of three subsystems and ARCVIEW is shown in Fig. 5. This figure shows that the three subsystems make use of ARCVIEW and a< IMG SRC = "P3425.GIF" ALT = "Integration of Sub-systems">
number of scripts developed by Avenue finally implement their integration. During the practical integration for those subsystems, those subsystems and ARCVIEW construct logically a simple star network where ARCVIEW is used as a switching node to implement a number of data exchanges among those subsystems, which is shown in Fig. 6. The star structure describes in practice a object-oriented design
and integration decision of the optimal management system of stored grain. From the star network, I can construct an ARCVIEW world to integrate all key modulars in those subsystems. This connection among those subsystems is facilitated by ARCVIEW or scripts developed by Avenue that translates data and procedure calls between subsystems and also controls execution of the entire system. The O-O design based on the star network does not allow subsystems to communicate directly. All communication is governed by the ARCVIEW real world model of stored grain application domain. The advantage of this method was that the management system would not be built around any specific type of subsystem, so as to make the system compatible with many more environments and applications. ARCVIEW real world model of Fig. 7 shows how to integrate all subsystems and
implement the O-O design. The ARCVIEW with Avenue, VISUAL BASIC 4.00 and VISUAL C++ 2.0 were used to develop various scripts, objects, programs and procedures for implementing the integration. In practical implementation of the system, we found that ARCVIEW 2.1 and VISUAL BASIC 4.0 provided very satisfactory user interfaces for our system, on the other hand, ARCVIEW 2.1 completed also some complex computation about graphic coverges for supporting the operation of graphic simulation and decision models. In the process to develop and implement the system, VISUAL C++ 2.0 was used to design various complex objects and to complete various complex numeric computation and simulation operation. Otherwise, our current research and achievements had shown that ARCVIEW 2.1 with Avenue is one of most efficient and flexible environments or frameworks for developing the optimal management system of stored grain. 5. DISCUSSION The prototype of optimal management system of stored grain was validated using a number of experimental data collected from various sources. In addition, the prototype system has been extensively validated by our team, who compared the system�s predictions and decisions with some field data collected at several sources. The final results for all resources was very satisfactory and with the predetermined performance range. The system is currently being evaluated technically. It is necessary to determine economic value of the system in application of practical stored grain management and to further develop simulation models to aid the analysis of complex stored grain environments. Further research is necessary to look into means of dangerous state prediction of stored grain in GIS environment, which is the most difficult area of the research project because of the high computation cost and respondent time of the current system. Further study is required to look into appropriate ways of increasing the precision of graphic simulation and decision models and decreasing their computation cost where Esri ArcInfo�s 3D function will be used to support the development. 6. ACKNOWLEDGMENTS The authors wish to acknowledge the valuable contributions of other members of our research team to the research. They also acknowledge funding of the research by China National Foundation of Natural Sciences. 7. REFERENCES Harrison, S. R., 1991. Validation of agricultural expert systems. Agric. Syst., 35: 265-286. Rumbaugh, J., Blaha, M., Premerlani, W., et. Al., (1991) Object- Oriented Modeling and Design. Prentice-Hall, Englewood Cliffs, NJ, 500 pp. Turban, E. (1992) Expert systems and applied artificial intelligence. Macmillan, New York. Power, J. M., 1993. Object-Oriented design of decision support systems in natural resource management. Compute. Electron. Agric., 8: 301-324. Lob, D. K., et al ., 1994. Integration of a rule-based expert system with GIS through a relational database management system for forest resource management. _, 11: 215-228. Chang, C. S. And J. L. Steele. 1995. Development and evaluation of aeration control straggles for maintaining stored grain quality. Applied Engineering in Agriculture 11(4): 577-582. Chang, C. S., H. H. Converse and J. L. Steele. 1994. Modeling of moisture content of grain during storage with aeration. Transactions of the ASAE 37(6): 1891-1898. Chang, C. S., H. H. Converse and J. L. Steele. 1993. Modeling of temperature of grain during storage with aeration. Transactions of the ASAE 36(2): 509-519. Singh, A. K., E. Leonardi and G. R. Thorpe. 1993. A solution procedure for the equations that govern three-dimensional free convection in bulk stored grains. Transactions of the ASAE 36(4): 1159-1173.