胡大伟
清明节,沉痛悼念Sven Eric Jørgensen教授 精选
2016-4-4 23:00
阅读:7822
标签:style, 生态, 热力学


近期在学习和思考生态热力学建模问题的过程中,有个问题想与Sven Jørgensen教授讨论一刚把我的问题发过去,不久就收到了他助手发来的一个令人无比震惊的消息:

We are sorry to inform you that Prof. Sven E. Jørgensen has passed away on March 5. He passed away suddenly but peacefully due to heart failure. This email account will no longer be used.

Sorry about the vacation title of the auto reply. We only have access to Svens email through his phone and it can't be changed.

Regards

Mette and Morten

顿时感觉失去了一位长者、一位亲人一样地悲恸。

1、初识Sven Jørgensen教授

最早知道Sven Jørgensen教授,是因为他的一本巨著“Handbook on Environmental Data and Ecological Parameters” (Oxford University Press,Oxford, 1979)2007年,俄罗斯专家来访,与Degermendzhy院士探讨生态系统的数学建模问题的时候,院士提到了这本书。于是我们立刻分头去找,找了北航的图书馆、北图、国图、……,都没有,最后终于在中国科学院文献情报中心找到了它,1161页,里面有动物、植物和微生物在不同环境因子下的各种生态学参数。我如获至宝,立刻复印了一本(馆藏不外借),至今珍藏着。

我当时在想,这是怎样的一个人,要怎样的博学、要花多少时间和精力,才能收集整理资料、完成这样一部百科全书式的宏篇巨著呢?在我看来,这样的人简直就是一个圣人。因为这样的人,今天在我国是绝不可能有的,学者们都很忙、很忙、很忙,不会有人做这种毫不利己、专门利人的事的。

我建立的很多模型的参数要么直接从该书中引用,要么以书中给出的参数值作为初始值进一步加以校正获得。

很想知识Sven Jørgensen教授是一位怎么样的人,可那时在我以目中,他只是一位遥不可及的偶像。

2、一篇Ecological Modeling文章的审稿

这些年我一直在思考生态系统的自组织问题,这绝不是用系统动力学的常微分方程模型可以解决的任务——因为它的模型结构是不能改变的,而生态系统的进化是质变,即内部结构的复杂化,而不是表观上的量变。我认为生物能够响应生态信息改变内部结构,以适应生态信息里包含的环境变化。建立了一个模型,并准备把它发表到Ecological Engineering,题目是:Robust stability mechanism of an artificial ecosystem based on biological mutations and synergies driven by ecologicalinformation可是没有想到这篇文章被送到了Sven Jørgensen教授手中,他能作为我文章的评阅人,我实在是太荣幸了。他给我来信说:

The paper is not ecological engineering, but a modeling / system ecology paper. I would recommend that you submit the paper to Ecological Modelling. I am in charge of being editor for a 40 year anniversary issue of Ecological Modelling and we would like to focus on where are we and where are we going in ecological modeling and systems ecology. Therefore, I would recommend you to send the paper to me msijapan@hotmail.com or to submit it to Ecological Modelling under the special anniversary issue, but let me before submission to me recommend, and some of the figures are improved and that the authors consider structurally dynamic modeling SDM which is close to the idea of the paper. SDM: there are several papers in Ecological modeling about SDM and you can read more about in Fundamentals of Ecological Modelling by Jørgensen and Fath (2011) and in Introduction to Systems Ecology by S.E. Jørgensen (2012). The paper would fit to the idea of the special issue but will of course be reviewed by 2-3 reviewers as always.

得知Sven Jørgensen教授是Ecological modeling的创刊人(1975)。我非常高兴,修改了一下格式后,就转投Ecological modeling,但没有想到文章引起了极大的争议,乃至最后被拒:

(1) This paper should be rejected for several reasons: even if the title states that the paper dealswith models collected from an artificial ecosystem, the introduction and theconclusions arbitrarily generalize the results to all ecosystems. The major drawback of the paper is that the use of the Lyapunov stability has not been proven in the paper or from literature references to be appropriate to analyze ecological systems. The paper also deals with the validation of the FSM model. No mention is made in the introduction that one of the purposes of the paper is to validate the FSM model.   The word"validation" in ecological modeling implies comparison of model simulation with data. No comprehensive statistical validation is done in this paper.   In the results the results ofthe stability analysis are described in a short paragraph.   No ecological results are included in this section. In the title the word "robust stability" is used but in the presentation of the Lyapunov indirect method there is no mention of the  "robust" property. In the abstract there is a statement that"the ecosystem stability was significantly underestimated ..." but there is no mention in the paper of this underestimation.   Thus, the reader is misled. The abstract generalizes the results of a modeling exercise of an artificial system to all natural ecosystems. No mention is made in the abstract of the mathematical stability criteria used in the paper. .

(2) The introduction states that the stability of ecosystems is "sustained creatures behaviorsresponse" however the authors do not explain to the reader how the formal mathematical definition of Lyapunov stability is related to populations. Thus, the reader is left hanging in this qualitative statement of stability that deals of the interaction between populations and "their surrounding". In the next sentence "mutation" and "synergy" are introduced but with no immediate relation with stability. We are then told that the literature pointed out that population models can not evaluate ecosystem stability. No references are given of past studies of ecosystem stability from the early seventies.  

(3) The authors thanstate the ODE models developed in the last 40 plus years are not sufficient to model complex populations behaviors and that finite state machines should be used. This is fine but now the purpose seems to be the modeling of populations and not the study of stability. The relation between stability and FSM should be stated here so that the reader understands the complete problem.

我都感到绝望了…………。然而2015年年底的时候收到了Jørgensen教授的来信,他说他力排众议,坚决将我的这篇文章选入Ecologicalmodeling40周年特刊。在特刊的首页,他评价道:Robust stability mechanism of an artificial ecosystem based on biological mutationsand synergies driven by ecological information by D. Hu, X. Du, L. Li, Y. Sun and J. Zhang presents a new tool in systems ecology to obtain knowledge about complexbehavior of ecosystems. The goal of this study is to discuss the perspective and method of modeling complicated biological behaviors such as mutation and synergy, and compare the sizes of the stability region of two types of ecologicalmodels in parametric space through digital simulation. The paper demonstrates that ecological models of artificial/virtual ecosystems can be applied to understand complicated biological behaviors and how the biological components in ecosystem are able to sustain balance of ecosystems. It will be interesting to see how this promising tool will be applied in the nearest future.

2001年读研,开始做理论生态学模型与计算机仿真实验,虽然我没有做出什么非常有价值的成果,但能得到Sven教授的认可,我非常高兴。

3、与Sven Jørgensen教授的数次通信

在接下来的几个月里面,我与教授通了12封信,主要是探讨生态系统的建模问题。我的每封信他都会仔细地回复,语气是那么的谦和,感觉不到一点高高在上的口气,他甚至说,他的工作可能都不一定是对的,你不要把它们作为教条来理解。我说在人工生态系统从事了近10年的建模工作,paper虽然发了一些,但我并不满意,因为我并没有真正找到驱动系统运行的真正的动力学原因,虽然我的模型都是认为生物与生物、生物与非生物环境之间的关系就是人工生态系统运行、演化的动力学原因,是它们让系统的状态发生变化,但还是没有把握住本质,预测的结果在理论和实践中往往并不奏效。他告诉我,他也做了一辈子的生态系统建模,以前和我现在认为的一样,后来他终于明白了,驱动生态系统运行与进化的动力学原因应该是Energy & Exergy,………………。

来不及多说了,还没有更深入的请教与探讨,先生就仙逝了!

Sven Jørgensen教授,谢谢您对我的支持与鼓励,您是世界理论生态学领域的泰斗,我只是一个默默无闻的晚辈,您能如此耐心、谦卑地与我讨论问题,是我无上的荣幸。

今天是中国的清明节,在这里向您致以最崇高的敬意!

在我今后的学术生涯里,一定继承您的遗志,完成您的部分未竟之业,以告慰您的在天之灵。



(1) Robust stability mechanism of an artificial ecosystem based on biological mutati.pdf

Editorial of ecological modelling

(2) Jorgensen's Comments.pdf

(3) Introduction to Systems Ecology.PDF      (4)Science in the Age of Computer - Winsberg, Eric_5608.pdf



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