| Agent-Based Framework for Forest Planning | |||||
| Author | Rasol Manaf� | ||||
| Abstract | Owing to dynamically changing environment inherent to forestry demands and expectations, a shift from application-centric to agent-centric for information processing often becomes necessary in forestry planning. Forest Management systems as a vital part of forest planning systems have to master these latest requirements, i.e. forest management systems have to deal with complexity and uncertainty. The motivation for this study is based on the study that a rigid centralized approach to forestry planning and control is no longer suitable. Therefore, this thesis advocates an agent-based approach as a means of supporting operationally resource-centered management systems towards a dynamic and flexible conduct, nowadays essential in forest planning. The core of this thesis presents a modeling and simulation framework integrating concepts of the fields of management dynamic, forest growth simulation management, artificial intelligence, and object-oriented concurrent programming. As such, the work is at the crossroads of these fields. The framework features three modeling levels. The resulting models can be verified separately utilizing the existing developed simulation kernel. Physical layout considerations-such as the projection of forest growth and yield -are mapped on the reactive level. Operational issues are addressed at the deliberative level, meaning that directions are given on how to activate a reactive system. Organizational structures and task responsibilities regarding the operations are modeled on the coordination level. The organizations being mapped on the management coordination level of this framework are multi-agent systems providing means for forest planning systems in their striving to improve their dynamically to the situational conditions of the envirinment. In order to efficiently support forest planning systems, multi-agent systems must follow the structural guidelines as proposed by forest management. Operationalized, the framework supports recursively structured multi-agent systems, in which the behaviors of planning, scheduling and execution can be found in every multi-agent system. Thus, a behavior determines an agent's entire action selection, denoted also as capabilities. The advanced level of dynamic conduct as a source for building multi-criteria decision making in forest planning is supported in a way that agents feature multiple levels of adaptation. Owing to the multi-level unified process, robustness can be gained by satisfying uncertainty. In order to maintain the system's consistency, the adjustment of agents' variety is brought about by the introduction of constraint blocks, so called Object Constraint Language (OCL) to be respected by them. The information base of agents is embodied by their knowledge bases and internal models. Additionally, a note has been made between problem solving agents (management agents) and decision-supporting agents (service agents). Multi-agent systems containing management agents are being developed on the coordination level and are subject to performance assessments regarding their organizational structure. The primary reason for the introduction of the coordination level is not the analysis of algorithmic competence, but rather to examine its utilization by problem solving agents. The conceptual development of agents is technically backed up by an implementation based on an active object approach, which allows agents communication and process autonomy. The conceptual separation of the three modeling levels is technically supported as well. However, agents must interfere on the deliberative level. Mediators or Agent Request Brokers as special types of service agents can encapsulate objects on the deliberative level. As a result, the mediators are able to redirect the information flow to managerial agents, which was originally connecting the objects on the deliberative level. Thus, these agents are, among other things, able to allocate resources differently than originally planned. |
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