作物害虫天敌微生物系统的动力学研究

以棉田生态系统能量流动分析为基础,建立了作物害虫天敌微生物的种群动力学模型,对作物害虫天敌微生物系统进行了初步的研究.对系统的能量流动使用微分方程进行了模拟,并对系统正平衡点的存在性及局部渐近稳定性给出了相关条件.最后使用MATLAB软件对模型进行了动态模拟,对正平衡点的存在性条件和稳定性进行了验证.     

微生物组学中的高维计数和成分数据分析

人体微生物组对人体健康和疾病起着重要作用.高通量测序技术的发展使得我们可以定量分析微生物组中所有菌种的成分.本文回顾近来在微生物组学研究中的高维计数和成分数据分析方法,其中包括Dirichlet多项分布模型及其拓展、从大维稀疏计数矩阵估计成分数据、高维成分回归和基于对数基底的成分数据统计推断方法.     

害虫胁迫下的棉田能量生态系统稳定性分析

在棉田生态系统的基础上研究了以能量为单位的能流数学模型,模型主要包括五个种群:棉株、害虫、捕食性天敌、寄生性天敌以及土壤微生物.基于模型使用微分方程模拟出了能量在各个每个物种之间的流动,并给出了系统的正平衡点存在性和稳定性的条件.最后使用Matlab软件对模型中各个种群的能量变化进行直观的模拟.旨在通过已知的模型在正平衡点处稳定的条件,对棉田生态系统的管理和系统控制提供理论指导.     

近岸海域赤潮藻非线性生态模型的建立和动力学分析

基于海洋浮游生态系统特性,以主要赤潮藻-中肋骨条藻为研究对象,建立了中肋骨条藻生物量随氮磷营养盐浓度变化的微分方程,并考虑了养料循环和时滞的影响,利用非线性动力学方法得到了边界平衡点的全局渐近稳定性,正平衡点的局部稳定性和Hopf分支的存在性,以及系统持久的充分条件.     

棉田生态系统时滞动力学模型及其应用

以棉田生态系统能量流动分析为基础,建立了作物-害虫-天敌-微生物的时滞种群动力学模型,利用泛函微分方程理论对该系统进行了持久性和稳定性研究,对系统解的正性、持久性、正平衡点的存在性及全局渐近稳定性给出了相关条件,证明该系统的时滞是无害时滞.最后使用MATLAB软件对模型进行了动态模拟,对正平衡点的存在性条件和稳定性进行了验证.     

微生物组学的大数据研究

微生物组学大数据在生态环境、人类健康和疾病研究方面都起到了重要作用。通过数学、统计等数据挖掘方法,从高维复杂数据中提取有用信息,是微生物组学大数据建模和分析的关键问题。本文分析了微生物组学大数据的特点,对当前数据分析和计算研究中存在的热点和难点进行了探讨分析,并综述了当前微生物组学大数据模式挖掘、网络重建与分析的研究概况。     

什么是随机动力系统

微生物组学大数据在生态环境、人类健康和疾病研究方面都起到了重要作用。通过数学、统计等数据挖掘方法,从高维复杂数据中提取有用信息,是微生物组学大数据建模和分析的关键问题。本文分析了微生物组学大数据的特点,对当前数据分析和计算研究中存在的热点和难点进行了探讨分析,并综述了当前微生物组学大数据模式挖掘、网络重建与分析的研究概况。     

红树林自然保护区湿地生态系统的数学模型及其应用

研究了红树林自然保护区自然环境和人类社会活动对于生态系统的影响,考虑了生物之间的相互关系,将生物量、生物生长的面积等作为主要指标,建立了常微分方程组模型,对生态系统的变化情况进行了描述,借助稳定性分析对方程进行了研究,并进行了数值模拟。根据理论分析和数值模拟的结果,对保护区的林木恢复工作提出了合理的建议。     

非线性生态系统的复杂动力学行为研究(Ⅲ)

本文继续文献[1～2]的研究,首先引进了生态系统的系综概念,在此基础上比较详细地讨论了生态协同学的微观方法和宏观方法.将这二者结合起来,利用生态系统输出(或可以测得)的宏观数据,建立广义金兹堡-朗道方程(GGLE),把握广义相变(群落演替)前后的信息变化,找出其微观对客观结果的作用机制,这也许是对复杂生态系统作用机制研究的一条新途径.     

基于Logistic模型的创新生态系统的种群关系研究

京津冀产业创新生态系统是京津冀协同发展的重要内容.从产业创新生态系统外部和内部两个角度对京津冀电子信息制造业创新生态系统进行剖析,一方面运用生态学理论构建京津冀电子信息制造业创新生态系统,借用Logistic模型分析京津冀区域电子信息制造业创新生态系统种群间的动态演化,协同效应初步显现;另一方面结合仿真方法模拟研究京津冀电子信息制造业创新生态系统内部各类种群之间的演化关系和演化规律.互惠共生是电子信息制造业创新生态系统演化的最佳关系模式.各创新主体之间不同的演化关系导致动态创新生态系统不同的演化方向,最终达到平衡状态,并提出相应对策建议.     

An approach to a metagenomic data processing workflow

Metagenomics is a rapidly growing field, which has been greatly driven by the ongoing advancements in high-throughput sequencing technologies. As a result, both the data preparation and the subsequent in silico experiments pose unsolved technical and theoretical challenges, as there are not any well-established approaches, and new expertise and software are constantly emerging.Our project main focus is the creation and evaluation of a novel error detection and correction approach to be used inside a metagenomic processing workflow. The approach, together with an indirect validation technique and the already obtained empirical results, are described in detail in this paper. To aid the development and testing, we are also building a workflow execution system to run our experiments that is designed to be extensible beyond the scope of error detection which will be released as a free/open-source software package.     

海洋立管涡激损伤分析的虚拟激励法概述

立管是连接海底钻井和海上平台的重要系统.涡激振动是造成立管疲劳损伤的主要因素.受海流的随机作用,立管涡激振动表现出不确定性,对这种随机振动进行快速有效地分析,对于立管的工程设计具有非常重要的意义.考虑随机激励作用,要比确定性激励困难得多,虚拟激励法对于克服这种困难具有很好的效果.近年来,应用虚拟激励法分析立管的涡激损伤问题,取得一些成果,该文对此作一概略的叙述.     

Merging bottom‐up and top‐down approaches to study prostate cancer biology

The sequencing of the human genome has opened new areas of possibility for understanding diseases such as cancers. Sequencing has given us the necessary building blocks for identifying the components of important signaling networks, whereas new tools such as automated gene sequencing, cDNA microassays, and tissue arrays are beginning to produce a torrent of data about these components. As we determine the components of these signaling networks, we can learn how the components are altered by transformations in the cell DNA. However, this torrent of information has also imposed a barrier: It is often unclear how to organize and use the data in ways that tell us more about the signaling networks. As with building blocks in a box, many of the components are still to be assembled into coherent structures. © 2002 Wiley Periodicals, Inc.     

基于灰色定权聚类法的广西北部湾海洋经济生态文明研究——灰色系统理论应用系列论文之四

广西北部湾海洋经济近年来发展迅速,与此同时,其海洋经济生态文明出现的问题也日益突出.通过借鉴生态文明指标,构建广西北部湾海洋经济生态文明指标,与珠三角相关指标数据进行对比,利用灰色定权聚类法对广西北部湾与珠三角的海洋经济生态文明程度进行评价,得出广西北部湾海洋经济生态文明为达标,珠三角海洋经济生态文明为良好的结论,从而提出调整北部湾海洋经济结构、加大海洋科技创新力度、完善海洋灾害预警与保障机制、提高海洋生态保护意识等对策建议,以期为政府制定相关决策提供科学依据.     

Sequencing and scheduling for filling lines in dairy production

We consider an integrated sequencing and scheduling problem arising at filling lines in dairy industry. Even when a processing sequence is decided, still a scheduling problem has to be solved for the sequence. This incorporates typical side constraints as they occur also in other sequencing problems in practice. Previously, we proposed a framework for general sequencing and scheduling problems: A genetic algorithm is utilized for the sequencing, incorporating a problem specific algorithm for the fixed-sequence scheduling. In this paper, we investigate how this approach performs for filling lines. Based on insights into structural properties of the problem, we propose different scheduling algorithms. In cooperation with Sachsenmilch GmbH, the algorithm was implemented for their bottleneck filling line, and evaluated in an extensive computational study. For the real data from production, our algorithm computes almost optimal solutions. However, as a surprising result, our simple greedy algorithms outperform the more elaborate ones in many aspects, showing interesting directions for future research.     

Chaotic dynamics of a simple oscillator — a pictorial introduction

That seemingly simple mechanical oscillators show already many general phenomena including local and global bifurcations as well as chaotic behavior makes their study so important in the theory of nonlinear dynamics. A considerable body of knowledge has been developed in recent years for analyzing and evaluating this variety of behavior. By studying a Duffing oscillator some well approved techniques are demonstrated and discussed. The presentation is highly illustrated to improve understanding.     

An optimization approach to the reconstruction of positional DNA sequencing by hybridization with errors

Positional DNA sequencing by hybridization (PSBH) is a recently proposed enhancement of DNA sequencing by hybridization (SBH, potentially a powerful alternative to the DNA sequencing by gel electrophoresis). It has been discussed in many papers and applied to large scale sequencing by hybridization. However, the computational part of PSBH reconstruction is a difficult problem, especially for the occurrence of hybridization errors. So far the problem has not been solved well. Taking PSBH as a combinatorial optimization problem, a novel reconstruction approach to PSBH is presented in this paper. The proposed approach accepts both the negative and positive errors and can greatly reduce ambiguities in the reconstruction of PSBH. The computational experiment shows that our algorithm works satisfactorily and correctly on the test data, especially for the positive errors and k-tuple repetitions.     

Behavioural modelling of career progression in the European Commission

Though manpower planning models have been part of OR for many years, and simulation has always been acknowledged as a potential approach, there are few reported applications of its use. In this case-based study we report on a micro-simulation model that exploits the structure of the European Commission’s appraisal and promotion rules, and includes regression-based sampling schemes which allow for non-Normal error terms to represent behavioural factors that led to the need for a new system. With a suitably parsimonious formulation the 20,000 person model runs very effectively, and the transparency associated with simulation proves an important factor in the successful use of the model as the basis for designing a promotion box system that was implemented across the Commission in 2009. The simulation modelling incorporates many Markov-type elements, and we reflect on important lessons learned from this combined use of micro-simulation and Markov-based approaches to manpower modelling.     

Numerical solutions of diffusive logistic equation

In this paper we investigate numerically positive solutions of a superlinear Elliptic equation on bounded domains.The study of Diffusive logistic equation continues to be an active field of research. The subject has important applications to population migration as well as many other branches of science and engineering. In this paper the “finite difference scheme” will be developed and compared for solving the one- and three-dimensional Diffusive logistic equation. The basis of the analysis of the finite difference equations considered here is the modified equivalent partial differential equation approach, developed from many authors these years.     

中国海洋经济可持续发展能力省际空间差异研究——基于组合综合评价方法

海洋经济可持续发展是实现海洋经济强国发展战略的重要手段,定量评价海洋经济可持续发展水平及其特征是合理开发海洋资源、发展海洋经济的重要保证.在构建我国海洋经济可持续发展能力评价指标体系基础上,运用组合综合评价方法定量分析我国11个沿海地区海洋经济可持续发展类型及其发展对策.