tailieunhanh - Integrated Assessment of Health and Sustainability of Agroecosystems - Chapter 4

Cố gắng để hiểu được mối tương quan giữa, một mặt, mục tiêu và mục tiêu của cộng đồng sống trong một Hệ sinh thái nông nghiệp và, mặt khác, kế hoạch hành động của họ, nhu cầu quy định, và mối quan tâm đòi hỏi sự hiểu biết của một hệ thống phức tạp. Một hệ thống liên quan đến nhiều biến số tương tác với nhau trong một quá trình năng động. Hơn nữa, định nghĩa của các biến này và mối quan hệ của họ phụ thuộc vào các cộng đồng nhận thức thế giới của họ | 4 Use of Systems Theory Directed Graphs and Pulse Process Models in an Adaptive Approach to Agroecosystem Health and Sustainability INTRODUCTION Attempts to understand the interrelationships between on the one hand goals and objectives of communities living in an agroecosystem and on the other hand their planned actions stated needs and concerns require the understanding of a complex system. Such a system involves many variables interacting with each other in a dynamic process. Furthermore the definition of these variables and their relationships depend on how the communities perceive their world. In attempting to model such a complex system one faces a trade-off between the accuracy of the model s predictions and the ability to obtain the detailed information needed to build the model Roberts and Brown 1975 . A system better referred to as a holon to distinguish it from a real-world assemblage of structures and functions is a representation of a situation and consists of an assembly of elements linked in such a way that they form an organized whole Flood and Carson 1993 . An element is a representation of some phenomena by a noun or a noun phrase. Links between elements represent a relationship between them. A relationship can be said to exist between two elements if the behavior of one is influenced or controlled by the other Flood and Carson 1993 . Behavior refers to changes in one or more important attributes of an element. Systems thinking involves formulating a holon and then using it to find out about gain insight into or engineer a part of the perceived world. The difficulty in formulating a holon to study the interrelationships among community values community goals planned actions and perceived problems arises from three predicaments. The first is that values goals and problems are socially constructed based on the perspectives of the stakeholders and these are sometimes divergent or conflicting Ison et al. 1997 . No one such perspective is sufficient