2003年, 第16卷, 第3期　刊出日期：2003-07-15

  

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  A CASE OF REFERENCE ON COMPLEXITY

  Jian SONG

  Journal of Systems Science and Complexity. 2003, 16(3): 289-292.

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  The author argues that the population system of human societies, the highest form of lives on the planet, may serve as standard paradigm for study of complex systems, it turned out to be a well investigable, nonlinearly controllable dynamic system, where census plays pivotal role. The theory has led China to succeed in checking the upsurge of population growth of 1970-80s and remains reliable basis for family-planning policy-making in all countries world-wide. It suggests that statistics could be a powerful tool in studying holistic properties of complex systems.
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  ADAPTIVE SYSTEMS THEORY: SOME BASIC CONCEPTS, METHODS AND RESULTS

  Lei GUO

  Journal of Systems Science and Complexity. 2003, 16(3): 293-306.

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  The adaptive systems theory to be presented in this paper consists of two closely related parts: adaptive estimation (or filtering, prediction) and adaptive control of dynamical systems. Both adaptive estimation and control are nonlinear mappings of the on-line observed signals of dynamical systems, where the main features are the uncertain-ties in both the system's structure and external disturbances, and the non-stationarity and dependency of the system signals. Thus, a key difficulty in establishing a mathematical theory of adaptive systems lies in how to deal with complicated nonlinear stochastic dy-namical systems which describe the adaptation processes. In this paper, we will illustrate some of the basic concepts, methods and results through some simple examples. The following fundamental questions will be discussed: How much information is needed for estimation? How to deal with uncertainty by adaptation? How to analyze an adaptive system? What are the convergence or tracking performances of adaptation? How to find the proper rate of adaptation in some sense? We will also ex-plore the following more fundamental questions: How much uncertainty can be dealt with by adaptation ? What are the limitations of adaptation ? How does the performance of adaptation depend on the prior information ? We will partially answer these questions by finding some "critical values" and establishing some "Impossibility Theorems" for the capability of adaptation, for several basic classes of nonlinear dynamical control systems with either parametric or nonparametric uncertainties.
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  VERTICAL HEREDITY VS. HORIZONTAL GENE TRANSFER: A CHALLENGE TO BACTERIAL CLASSIFICATION

  Bai Lin HAO;Ji QI

  Journal of Systems Science and Complexity. 2003, 16(3): 307-314.

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  The diversity and classification of microbes has been a long-standing issue. Molecular phylogeny of the prokaryotes based on comparison of the 16S rRNA sequences of the small ribosomal subunit has led to a reasonable tree of life in the late 1970s. How-ever, the availability of more and more complete bacterial genomes has brought about complications instead of refinement of the tree. In particular, it turns out that different choice of genes may tell different history. This might be caused by possible horizontal gene transfer (HGT) among species. There is an urgent need to develop phylogenetic methods that make use of whole genome data. We describe a new approach in molecular phylogeny, namely, tree construction based on K"-tuple frequency analysis of the genomic sequences. Putting aside the technicalities, we emphasize the transition from randomness to determin-ism when the string length K increases and try to comment on the challenge mentioned in the title.
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  NOISY OBSERVATION BASED STABILIZATION AND OPTIMIZATION FOR UNKNOWN SYSTEMS

  Han Fu CHEN

  Journal of Systems Science and Complexity. 2003, 16(3): 315-326.

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  The paper addresses optimization of a performance function which either is optimized via stabilizing and controlling the underlying unknown system or is directly optimized on the basis of its noise-corrupted observations. For the first case the unknown system is identified and then the indirect adaptive control approach is applied to optimize the performance function. For the second case the stochastic approximation method is used to optimize the objective function, and it appears that a number of problems arising from applications may be reduced to the one solvable by this approach. The paper demonstrates some basic results in the area, but with no intention to give a complete survey.
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  THE J STRUCTURE IN ECONOMIC EVOLVING PROCESS

  Fu Kang FANG;Qing Hua CHEN

  Journal of Systems Science and Complexity. 2003, 16(3): 327-338.

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  The economic evolution exhibits complexity. Behind the variable and fluctuant economic data there exists basic characters and rules. One basic structure in economic evolving process called as "J" structure is studied by us. This kind of structure exists in a wide area, such as economic growth, technology innovation, international trade, education, human capital, ecology aud environment etc. From the view of economic evolution, J structure has the character that system should suffer the pressure of initial investment with profit decreasing but get larger return afterwards. It is a kind of adaptation in complex economic systems; it reflects the adaptive and reformative ability of the system under the surrounding change. We illustrate the J structure by discussing economic growth. Based on a two-dimension dynamic system the geometric character and mechanism of J structure are studied, also the phase graphs with its condition are given. Also some further works are discussed.
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  EXTERNAL AND INTERNAL CONTROL IN PLANT DEVELOPMENT

  Beata Oborny

  Journal of Systems Science and Complexity. 2003, 16(3): 339-349.

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  Bodies of plants are modularly organized. Development proceeds by adding new modules to open endings with a potential for branching. Each module is autonomous to some extent. Development relies on the self-organized patterns that emerge from the interactions of individual modules. Interactions include both competition and cooperation, and several types of positive and negative feedback loops are involved. Development can be open to external influences, thus enabling the plant to adjust its form to the environment, for example, to the spatial distribution of ecological resources. This paper provides a review on adaptive plasticity in plants.
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  ON COMPLEX DYNAMIC CONTROL SYSTEMS

  Dai Zhan CHENG

  Journal of Systems Science and Complexity. 2003, 16(3): 350-357.

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  This paper presents some recent works on the control of dynamic systems, which have certain complex properties caused by singularity of the nonlinear structures, structure-varyings, or evolution process etc. First, we consider the structure singularity of nonlinear control systems. It was revealed that the focus of researches on nonlinear control theory is shifting from regular systems to singular systems. The singularity of nonlinear systems causes certain complexity. Secondly, the switched systems are considered. For such systems the complexity is caused by the structure varying. We show that the switched systems have significant characteristics of complex systems. Finally, we investigate the evolution systems. The evolution structure makes complexity, and itself is a proper model for complex systems.
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  SYNCHRONIZATION IN COMPLEX DYNAMICAL NETWORKS

  Xiao Fan WANG

  Journal of Systems Science and Complexity. 2003, 16(3): 358-371.

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  In the past few years, the discovery of small-world and scale-free properties of many natural and artificial complex networks has stimulated increasing interest in further studying the underlying organizing principles of various complex networks. This has led to significant advances in understanding the relationship between the topology and the dynamics of such complex networks. This paper reviews some recent research works on the synchronization phenomenon in various dynamical networks with small-world and scale-free connections.
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  EMERGENCE FROM LOCAL EVALUATION FUNCTION

  Jing HAN;Qing Sheng CAI

  Journal of Systems Science and Complexity. 2003, 16(3): 372-390.

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  This paper presents a new look on emergence from the aspect of locality and globality of evaluation functions for solving traditional computer problems. We first translate the Constraint Satisfaction Problem (CSP) into the multi-agent system, and then show how a global solution emerges from the system in which every agent uses a local evaluation function to decide its action, while comparing to other traditional algorithms, such as Local search and Simulated Annealing which use global evaluation functions. We also give some computer experimental results on large-scale JV-queen problems and k-Coloring problems, and show that emergence only depends on problem instance, not details of agent settings, i.e. in some CSPs, the system can self-organize to a global solution, but can not in some other CSPs no matter what settings of agents have.
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  ON COMPLEXITY OF POWER SYSTEMS

  Jin MA;Dai Zhan CHEN;Yi Guang HONG;Yuan Zhang SUN

  Journal of Systems Science and Complexity. 2003, 16(3): 391-403.

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  The power system is a classical example of complex systems. In this paper it is shown that the power industry in China is facing a tremendous challenge. The complexity in power systems is investigated as follows. First, the cascade failure in power systems is analyzed, and compared with sand-pile model. Next, we show that the agent-based modelling is a proper way for power network. Mathematically, the geometric dynamics and differential inclusion are useful tools for the stability analysis of large scale power systems. As for power market, the game theory and generalized control system model are proposed. For a complex power system, an evolutive model may be more accurate in description and analysis. Finally, certain newly developed numerical methods in the power system computation are introduced. Overall, we are convinced that the theorem of complexity, combined with modern control theory, may be the right way to answer the challenges faced by the power industry in China.
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  SWITCHING CONTROL: FROM SIMPLE RULES TO COMPLEX CHAOTIC SYSTEMS

  Jin Hu LU

  Journal of Systems Science and Complexity. 2003, 16(3): 404-413.

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  This paper reviews and introduces some simple switching pieeewise-linear controllers, which can generate complex chaotic behaviors from simple switching systems. The mechanism of simple switching rules creating complex chaotic behaviors is further investigated.