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Stability switch of tumor-immune system driven by delayed response in cell-to-cell contact

The European Physical Journal Special Topics 2024年第1期234卷 165-178页

作者： Xu, Qian Fan, Aili Qu, Lijin Miao, Yuchen Du, Lin School of Mathematics and Statistics Northwestern Polytechnical University Xi’an China MIIT Key Laboratory of Dynamics and Control of Complex Systems Xi’an China MOE Key Laboratory for Complexity Science in Aerospace Xi’an China

Considering the delayed response in cell-to-cell contact is essential for accurately predicting the progression of cancer. In this paper, the stability switch phenomenon of a tumor-immune interaction system induced by the delayed response is presented. Firstly, the qualitative properties of the system including non-negativity and boundedness of the solutions are discussed. Subsequently, a complete discriminant system for polynomials method is employed to scrutinize the local stability switch conditions, which circumvents the complicated calculation procedures and enhances the analytical accuracy for high-dimensional nonlinear time-delay systems. The delayed response in cell-to-cell contact is observed to exert a suppressive influence on system stability. Specifically, the system with stable initial state will switch to instability when the delayed responding time of cell-to-cell contact exceeds a critical threshold, indicating a weakened resistance of the immune system against tumor cells. While the system with unstable initial state will maintain and even exhibit chaotic behavior, implying uncontrolled tumor proliferation. Finally, the major findings related to cancer therapy are summarized in the conclusion. These results help to understand the complex mechanism of the tumor-immune system and provide ideas for the clinical treatment of tumor.

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Emergence of social cooperation in threshold public goods games with collective risk

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Physical Review E 2009年第1期80卷 016101-016101页

作者： Jing Wang Feng Fu Te Wu Long Wang Center for Systems and Control State Key Laboratory for Turbulence and Complex Systems College of Engineering Peking University Beijing 100871 China Program for Evolutionary Dynamics Harvard University One Brattle Square Cambridge Massachusetts 02138 USA

In real situations, people are often faced with the option of voluntary contribution to achieve a collective goal, for example, building a dam or a fence, in order to avoid an unfavorable loss. Those who do not donate, however, can free ride on others’ sacrifices. As a result, cooperation is difficult to maintain, leading to an enduring collective-risk social dilemma. To address this issue, here we propose a simple yet effective theoretical model of threshold public goods game with collective risk and focus on the effect of risk on the emergence of social cooperation. To do this, we consider the population dynamics represented by replicator equation for two simplifying scenarios, respectively: one with fair sharers, who contribute the minimum average amount versus defectors and the other with altruists contributing more than average versus defectors. For both cases, we find that the dilemma is relieved in high-risk situations where cooperation is likely to persist and dominate defection in the population. Large initial endowment to individuals also encourages the risk-averse action, which means that, as compared to poor players (with small initial endowment), wealthy individuals (with large initial endowment) are more likely to cooperate in order to protect their private accounts. In addition, we show that small donation amount and small threshold (collective target) can encourage and sustain cooperation. Furthermore, for other parameters fixed, the impacts of group size act differently on the two scenarios because of distinct mechanisms: in the former case where the cost of cooperation depends on the group size, large size of group readily results in defection, while easily maintains cooperation in the latter case where the cost of cooperation is fixed irrespective of the group size. Our theoretical results of the replicator dynamics are in excellent agreement with the individual based simulation results.

关键词： cooperation mechanisms simulation results Dilemma Simulation results Endowments Group Size zero fare public goods Threshold Replication Origin Emergence group cooperation

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Batch-to-Batch Optimization with Model Adaptation Leveraging Gaussian Processes: The Case of Optogenetically Assisted Microbial Consortia 23

Batch-to-Batch Optimization with Model Adaptation Leveraging...

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23rd International Conference on control, Automation and systems, ICCAS 2023

作者： Espinel-Rios, Sebastian Kok, Rudolph Klamt, Steffen Avalos, Jose L. Findeisen, Rolf Analysis and Redesign of Biological Networks Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany Princeton University Department of Chemical and Biological Engineering Princeton United States Institute for Automation Engineering Otto von Guericke University Magdeburg Magdeburg Germany Control and Cyber-Physical Systems Laboratory TU Darmstadt Germany

ISBN: (纸本)9788993215274

Microbial consortia are promising biotechnological production systems with the potential to divide complex metabolic pathways into smaller submodules, as well as make products and consume substrates that monocultures cannot. Maintaining optimal cell population levels and preventing mono culture formation challenge bioproduction by microbial consortia. Optogenetics allows for regulating the expression of key growth-regulatory genes through light to modulate cell population levels. Model-based dynamic optimization can determine optimal light trajectories and inoculum sizes that maximize product synthesis while satisfying system constraints, e.g., safety, economic, or technical aspects. Further-more, closed-loop dynamic optimization can address system uncertainty to a certain extent;however, its implementation is challenging due to limited online sensors. Alternatively, here we propose to perform open-loop optimization with batch-to-batch model adaptation based on Gaussian processes for maximizing bioproduction by optogenetically assisted consortia. The proposed approach enables knowledge transfer from existing to new models, improving predictability and optimization performance in each batch while avoiding costly and time-consuming modeling experiments. Compared to closed-loop optimization, this strategy is easier to implement as it does not rely on online monitoring, contributing to the state of the art in optimizing bioproduction by microbial consortia. We outline the applicability of the approach using simulation experiments of an optogenetically assisted consortium for the biosynthesis of the flavonoid naringenin, considering both parameter and model structure uncertainty. © 2023 ICROS.

关键词： Substrates

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Consensus of population systems with community structures

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Physical Review E 2008年第5期78卷 051923-051923页

作者： Jing Wang Bin Wu Long Wang Feng Fu Center for Systems and Control State Key Laboratory for Turbulence and Complex Systems College of Engineering Peking University Beijing 100871 China Program for Evolutionary Dynamics Harvard University One Brattle Square Cambridge Massachusetts 02138 USA

Multicommunity population systems may reach a consensus state where the fractions of each species in different communities agree on a common value. In this paper, by analyzing the evolutionary dynamics based on an extended replicator equation incorporating community effects, the consensus problem of population systems with n communities is studied. In particular, the simple case of two communities is investigated in detail. In general, for n communities, a sufficient and necessary condition for population systems to reach a consensus of coexistent state is provided. Regarding the population dynamics for the four different types of games, whether the population systems can achieve consensus is determined. The dynamics of community-structured populations shows richer features than nonstructured populations, and some nontrivial phenomena arising from different community-structured population systems are illustrated with concrete numerical examples.

关键词： Population dynamics

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基于反常热传导的分数阶热弹耦合理论

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Acta Mechanica Sinica 2024年第5期40卷 141-149页

作者：尉亚军吴华邓子辰 School of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University Xi’an 710072 China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical University Xi’an 710072 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong University Xi’an 710049 China

原子模拟和实验研究表明低维纳米材料具有反常热传导特性,建立唯象反常热弹耦合模型,研究强热传导导致的热力耦合响应,对微纳器件的安全稳定运行至关重要.本文旨在从反常热传导的视角重新审视分数阶热弹耦合模型。反常热传导由第二声效... 详细信息

原子模拟和实验研究表明低维纳米材料具有反常热传导特性,建立唯象反常热弹耦合模型,研究强热传导导致的热力耦合响应,对微纳器件的安全稳定运行至关重要.本文旨在从反常热传导的视角重新审视分数阶热弹耦合模型。反常热传导由第二声效应引起,考虑波动热传导理论,建立了波动热传导与粘弹性理论的类比,阐明了Cattaneo-Vernotte模型和Green-Naghdi模型的关联.通过引入分数阶导数,构建了基于Cattaneo-Vernotte和Green-Naghdi理论的分数阶热弹耦合模型。数值结果表明:对分数阶次区间[O,1],分数阶Cattaneo-Vernotte(FCV)I模型和分数阶Green-Naghdi(FGN)I-III模型都能预测反常热弹耦合响应:比经典热弹性理论更高的温度和应力;温度和应力随时间的变化显示:FGNII模型在所有时间范围内都能得到反常响应.对Green-Naghdi模型及其分数阶模型的进一步系统研究,有助于揭示反常热传导和热弹耦合机理,并促进纳米材料的广泛应用.

关键词：粘弹性理论分数阶导数热弹耦合热弹性理论热传导低维纳米材料分数阶模型微纳器件

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Effects of heterogeneous wealth distribution on public cooperation with collective risk

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Physical Review E 2010年第1期82卷 016102-016102页

作者： Jing Wang Feng Fu Long Wang Center for Systems and Control State Key Laboratory for Turbulence and Complex Systems College of Engineering Peking University Beijing 100871 China Program for Evolutionary Dynamics Harvard University One Brattle Square Cambridge Massachusetts 02138 USA

The distribution of wealth among individuals in real society can be well described by the Pareto principle or “80-20 rule.” How does such heterogeneity in initial wealth distribution affect the emergence of public cooperation, when individuals, the rich and the poor, engage in a collective-risk enterprise, not to gain a profit but to avoid a potential loss? Here we address this issue by studying a simple but effective model based on threshold public goods games. We analyze the evolutionary dynamics for two distinct scenarios, respectively: one with fair sharers versus defectors and the other with altruists versus defectors. For both scenarios, particularly, we in detail study the dynamics of the population with dichotomic initial wealth—the rich versus the poor. Moreover, we demonstrate the possible steady compositions of the population and provide the conditions for stability of these steady states. We prove that in a population with heterogeneous wealth distribution, richer individuals are more likely to cooperate than poorer ones. Participants with lower initial wealth may choose to cooperate only if all players richer than them are cooperators. The emergence of pubic cooperation largely relies on rich individuals. Furthermore, whenever the wealth gap between the rich and the poor is sufficiently large, cooperation of a few rich individuals can substantially elevate the overall level of social cooperation, which is in line with the well-known Pareto principle. Our work may offer an insight into the emergence of cooperative behavior in real social situations where heterogeneous distribution of wealth among individual is omnipresent.

关键词： Pareto principle

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Path integral solutions for n-dimensional stochastic differential equations underα-stable Lévy excitation

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Theoretical & Applied Mechanics Letters 2023年第2期13卷 98-112页

作者： Wanrong Zan Yong Xu Jürgen Kurths School of Mathematics Northwest UniversityXi’an710127China Department of Applied Mathematics Northwestern Polytechnical UniversityXi’an710129China MIIT key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi’an710129China Potsdam Institute for Climate Impact Research Potsdam14412Germany Department of Physics Humboldt University of BerlinBerlin12489Germany

In this paper,the path integral solutions for a general n-dimensional stochastic differential equa-tions(SDEs)withα-stable Lévy noise are derived and ***,the governing equations for the solutions of n-dimensional SDEs under the excitation ofα-stable Lévy noise are obtained through the characteristic function of stochastic ***,the short-time transition probability density func-tion of the path integral solution is derived based on the Chapman-Kolmogorov-Smoluchowski(CKS)equation and the characteristic function,and its correctness is demonstrated by proving that it satis-fies the governing equation of the solution of the SDE,which is also called the Fokker-Planck-Kolmogorov ***,illustrative examples are numerically considered for highlighting the feasibility of the proposed path integral method,and the pertinent Monte Carlo solution is also calculated to show its correctness and effectiveness.

关键词： Path integral method α-stable Lévy noise Monte carlo method Fokker-Planck-Kolmogorov equation

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Generation of Code for Reading Data from the Declarative File Format Specifications Written in Language FlexT

Generation of Code for Reading Data from the Declarative Fil...

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Ivannikov ISPRAS Open Conference (ISPRAS)

作者： Alexei Hmelnov Hmelnov Andrei Mikhailov Laboratory of Complex information systems Matrosov Institute for System Dynamics and Control Theory of Siberian Branch of Russian Academy of Sciences Irkutsk Russia

ISBN: (纸本)9781728112763;9781728112756

The language FlexT (Flexible Types) is intended for specification of binary data formats. The language is declarative and designed to be well understood for human readers. Its main elements are the data type declarations, which look very much like the usual type declarations of the imperative programming languages, but are more flexible. While the primary purpose of the language FlexT development was to make the binary data understandable by displaying them according to the format specifications, recently we have implemented the code generator, which can produce data reading code in some imperative languages from the specifications. By now we have implemented the code generation for the most widely used FlexT data types, but some complex types like that used in specifications of machine instructions' encoding are not supported yet. The current capabilities of the code generator are well characterized by that it have successfully produced a full-featured data reader code for the well-known for the GIS community Shape file format. In the article we first give a review of the features of the modern projects oriented to specification of binary file formats and consider their code generation capabilities. Then we briefly review the main features of the FlexT language. Finally we describe the main approaches that we use for the code generation.

关键词： Protocols Computer languages Generators Task analysis Syntactics Arrays Encoding

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Constrained Gaussian Process Learning for Model Predictive control ⁎

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IFAC-PapersOnLine 2020年第2期53卷 971-976页

作者： Janine Matschek Andreas Himmel Kai Sundmacher Rolf Findeisen Laboratory for Systems Theory and Automatic Control Otto von Guericke University Magdeburg Germany Process Systems engineering Otto von Guericke University Magdeburg Germany Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany

Many control tasks can be formulated as tracking problems of a known or unknown reference signal. examples are motion compensation in collaborative robotics, the synchronisation of oscillations for power systems or the reference tracking of recipes in chemical process operation. Both the tracking performance and the stability of the closed-loop system depend strongly on two factors: Firstly, they depend on whether the future reference signal required for tracking is known, and secondly, whether the system can track the reference at all. This paper shows how to use machine learning, i.e. Gaussian processes, to learn a reference from (noisy) data while guaranteeing trackability of the modified desired reference predictions within the framework of model predictive control. Guarantees are provided by adjusting the hyperparameters via a constrained optimisation. Two specific scenarios, i.e. asymptotically constant and periodic REFERENCES, are discussed.

关键词： Gaussian processes trajectory tracking learning supported model predictive control

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Shapiro steps and chaos in the Frenkel-Kontorova model with substrate lateral vibration

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Physical Review E 2022年第4期106卷 044204-044204页

作者： Yongfeng Wei Youming Lei School of Mathematics and Statistics Northwestern Polytechnical University Xi'an 710072 China Ministry of Industry and Information Technology Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical University Xi'an 710072 China

Numerical simulations are used to examine the dynamics of the dc-driven Frenkel-Kontorova model with an oscillation substrate subjected to lateral periodic excitations in overdamped and underdamped cases, respectively. The results reveal that the system exhibits frequency locking and chaotic behaviors due to the fact that the lateral vibration of the substrate potential introduces an additional frequency and degree of freedom into the system. In the overdamped case, we show that the appearance of subharmonic Shapiro steps can be attributed to the deformation of the substrate potential or inertia. The characteristics of the steps are significantly affected by the amplitude and frequency of the lateral vibration. When the vibration frequency is relatively high, the change of the width of the first harmonic Shapiro step with increasing amplitude exhibits a Bessel-type oscillation, but the oscillation deviates from the Bessel curve at lower frequencies. In the amplitude dependence, although the oscillatory behavior of the critical depinning force at the high frequency is anomalous, local maxima (minima) of the first step width correspond to local minima (maxima) of the critical depinning force, and the largest Lyapunov exponent obtained in the pinned state represents a mirror relationship of the critical depinning force. In contrast to the overdamped system, the underdamped one exhibits both subharmonic Shapiro steps and chaotic behaviors. We show the increased inertia of the latter system plays an important role in suppressing the emergence of subharmonic steps, which is opposite to the result of the former. When the dc force changes, chaos appears not only between adjacent subharmonic Shapiro steps but also on some specific steps where chaos should be avoided. The variation regularity of the first step width and the critical depinning force is thus annihilated in vibration amplitude and frequency dependence. However, superlubricity can be achieved by careful adjustmen

关键词： Chaos Classical mechanics Coupled oscillators Synchronization

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