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6.2. VEGETATION SUCCESSIONDr. Ian Noble This system is among the first ecological-oriented advisors reported to be in operation. It is considered a pioneer system in its field and has been field tested and deployed with some measurable success. This expert system on vegetation succession demonstrates capabilities of predicting the alternating changes in ecosystems. The system includes knowledge of the species known to exist in the communities of the various successional states of vegetation. The purpose of the system is to provide advice regarding vegetation dynamics and succession. This advice is pertinent in situations to determine the effects on a particular ecological system if it is subjected to man-controlled manipulation in some way. Such situations could be related to the management and protection of vegetation against fires. Sometimes, small bush fires are beneficial and may prevent the occurrence of a large and hot fire that can have devastating effects. It can also be applied in management of shifting cultivation in Third World countries. The system uses predicate logic to operate its rule base. According to Jeffers (Jeffers 85), the system was successfully tested on community problems in Australia and China. 6.3. TSDSYS: TREATMENT STORAGE AND DISPOSAL SYSTEMHushon Judith Hushon (Hushon 91) reports on a number of systems in a 1991 paper. All of them deal with so-called First Emergency Response systems that treat aspects of accidental releases of chemicals and waste. Some of the systems reported blend into what can be termed the "health-oriented universe." Yet, at the heart of most of these system are the issues of pollution control and environmental protection. One of these early initiatives was the TSDSYS program. The purpose of the system was to meet the need for some kind of assistance for early responders to emergency situations. They need help to identify appropriate contractors for treating, storing, and disposal of chemicals and waste that pose a threat to the environment. This recognition process is complicated because of time constraints and the fact that the government requires three bids, thus imposing the need for multiple contacts. The system is fed with input like the type of waste and the potential pollutant chemicals involved. The geographic location may also be important. The system will in return provide a short summary of information on each vendor that meets the search criteria. This output is sufficient for making telephone contact with the service contractor. If desired, a more extensive output can be produced. This will include elaboration on the types of chemicals confronted with and the type of process that the service company is likely to undertake. With this, there are implications for a first response on site. The system consists of a rule-driven interface and a database. The data was gathered from in-house reports, practical experience, and service directories. TSDSYS was originally designed for the KES expert system shell for operation on a PC/AT-type machine. Its intended users were scientists and technical personnel. Due to the fact that the database required revision three times a year, it became evident that it would be too costly to do maintenance on many stand-alone versions. The application was then reprogrammed in DM and implemented on a VAX 8350. Once having established the rule concepts with KES, the transition to DM worked well. A rule-based, forward-chaining system exploits the database. The assistance teams that were supposed to use this system were equipped with Crosstalk script files to accomplish dial-up and login to the central system. The interaction was patterned after the one originally designed for the PC. The system was deployed in 1987 and has been commercially available since then. 6.4. SIRENASMurcia et al. SIRENAS is a decision support system for management of release emergencies. Its purpose is to yield interpretations of accidental situations as quickly as possible, despite lack of data (Murcia 94). The system supports the task of determining what kind of release of hazardous material accompanies a given accident. This is done by providing the system with the physical characteristics of the situation. The system simulates a contamination scenario. It applies knowledge about surface dispersion, groundwater dispersion, or atmospheric dispersion to do this. The results of a working session is a graphic output that represents the evolution of the pollution from the beginning of the accident to the moment the concentration is not yet dangerous. At the end, the system provides an overview about the effect of the toxic substances on both human health and the environment. The knowledge base built is a synthesis of expertise from many individuals. The application was developed partly in C/C++ and the MFC-SDK programming language. NEXPERT OBJECT, the expert system development tool was applied for the knowledge engineering task. Physical data and material specifications, including their toxity, is maintained by an ORACLE RDBMS.
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