复杂系统.pdf

系统科学系统科学
与与 复杂网络复杂网络
狄增如狄增如
北京师范大学管理学院系统科学系北京师范大学管理学院系统科学系
北京师范大学复杂性研究中心北京师范大学复杂性研究中心

Simple Complicated
Complex System
Complex Systems
Complex Systems
Complex systems are all around us:
–
economies
–
nature: ant, bee, bird colonies
–
little robots
Complex systems
„ Often-cited examples of complex systems in
nature and society include the brain, the
immune system, biological cells, metabolic
networks, ant colonies, the Internet and
World Wide Web, economic markets, and
human socialnetworks.
„ There is no generally accepted formal
definition of “complex system”. Informally, a
complex system is a large network of
relatively simple components with no central
control, in which emergent complex
behavior is exhibited.
„ 生物系统
„ 社会经济系统
Complexity Research ————
UnderstandingUnderstanding andand EngineeringEngineering EmergenceEmergence
„ Complex systems have many autonomous units
with adaptive capabilities, and show important
emergent phenomena.
„ One of the greatest challenges in building a science
of such systems is precisely to understand – how it
is that micro level properties determine or at least
influence those on the macro level.
„ Our current lack of understanding presents a huge
obstacle in designing systems with specified
behavior – to design the units of a system, their
interactions and adaptive features, so as to achieve
a targeted behavior from the whole.
Complexity Approach
Emergent properties:
Local and simple interactions
Global behavior
The emergence of dynamical structures
in complex systems
系统科学
„ 《1999科学发展报告》
系统科学是自然科学与社会科学的基础学
科。它关心涉及复杂系统性质和演化规律的基
本科学问题，试图通过对生命、生态、信息技
术、资源环境、社会经济等具体系统演化过程
中关键问题的研究，揭示复杂系统所具有的一
般性规律，研究复杂系统宏观层次上的涌现性
行为、系统性质和功能的智能控制等科学问题
，并促进对具体系统的认识。
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