检索结果-内蒙古大学图书馆

Group size matters: Synergistic effects and reduced inequality in performance rankings

PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2025年 665卷

作者： Reia, Sandro M. Pfoser, Dieter Campos, Paulo R. A. George Mason Univ Coll Sci Geog & Geoinformat Sci 4400 Univ Dr Fairfax VA 22030 USA Univ Fed Pernambuco Ctr Ciencias Exatas & Nat Dept Fis Ave Prof Moraes Rego 1235 BR-50670901 Recife PE Brazil

Contemporary society often employs ranking systems to evaluate and reward individual performances based on meritocratic principles. However, these systems can have unintended consequences, impacting creativity and equality. This study presents a statistical analysis of a ranking performance model to examine the implications of these systems on social dynamics. Using a simulation approach, we explore the role of imitation in determining individuals' success and how these dynamics influence overall group productivity and inequality. Our results unveil a synergistic effect of increasing group size and enhancing collective output while reducing individual performance inequality. Additionally, we investigate the social dynamics on random graphs, scale-free, and small-world networks to understand the influence of network topology, showing that connectivity within the group significantly influences both performance and inequality. Our results also demonstrate that high clustering combined with short path lengths reduces inequalities. These findings provide insights into optimizing ranking systems to balance merit-based recognition with the need for innovation and equality, suggesting strategies to enhance group synergy.

关键词： Agent-based models Computational social science Collective dynamics Social systems patterns in complex systems

来源：评论

学校读者我要写书评

暂无评论

The importance of the incubation time distribution in compartmental epidemiological models

引用

PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2024年 650卷

作者： Rozan, E. A. Kuperman, M. N. Bouzat, S. Univ Nacl Cuyo Inst Balseiro Mendoza Argentina Consejo Nacl Invest Cient & Tecn CONICET San Carlos De Bariloche Argentina Ctr Atom Bariloche Comis Nacl Energia Atom Gerencia Fis San Carlos De Bariloche Argentina

This study investigates the utilization of various mathematical models for comprehending and managing outbreaks of infectious diseases, with a specific focus on how different distributions of incubation times influence predictions regarding epidemics. Two methodologies are examined: a compartmental SEnIR ODE model, which represents an enhanced version of the mean-field SEIR model, and a stochastic agent-based complex network model. Our findings demonstrate that the selection of diverse incubation time distributions can result in noteworthy discrepancies in critical epidemic forecasts, highlighting the crucial role of precise modeling in shaping effective public health interventions. The research underscores the necessity of integrating authentic distribution patterns into epidemic modeling to increase its reliability and applicability.

关键词： Mathematical epidemiology Epidemic modeling Incubation periods patterns in complex systems Compartmental models complex networks

来源：评论

学校读者我要写书评

暂无评论

Swarming in viscous fluids: Three-dimensional patterns in swimmer- and force-induced flows

引用

Physical Review E 2016年第4期93卷 043112-043112页

作者： Yao-Li Chuang Tom Chou Maria R. D'Orsogna Department of Mathematics CSUN Los Angeles California 91330-8313 USA and Department of Biomathematics UCLA Los Angeles California 90095-1766 USA Departments of Biomathematics and Mathematics UCLA Los Angeles California 90095-1766 USA

We derive a three-dimensional theory of self-propelled particle swarming in a viscous fluid environment. Our model predicts emergent collective behavior that depends critically on fluid opacity, mechanism of self-propulsion, and type of particle-particle interaction. In “clear fluids” swimmers have full knowledge of their surroundings and can adjust their velocities with respect to the lab frame, while in “opaque fluids” they control their velocities only in relation to the local fluid flow. We also show that “social” interactions that affect only a particle's propensity to swim towards or away from neighbors induces a flow field that is qualitatively different from the long-ranged flow fields generated by direct “physical” interactions. The latter can be short-ranged but lead to much longer-ranged fluid-mediated hydrodynamic forces, effectively amplifying the range over which particles interact. These different fluid flows conspire to profoundly affect swarm morphology, kinetically stabilizing or destabilizing swarm configurations that would arise in the absence of fluid. Depending upon the overall interaction potential, the mechanism of swimming ( e.g., pushers or pullers), and the degree of fluid opaqueness, we discover a number of new collective three-dimensional patterns including flocks with prolate or oblate shapes, recirculating pelotonlike structures, and jetlike fluid flows that entrain particles mediating their escape from the center of mill-like structures. Our results reveal how the interplay among general physical elements influence fluid-mediated interactions and the self-organization, mobility, and stability of new three-dimensional swarms and suggest how they might be used to kinetically control their collective behavior.

关键词： patterns in complex systems Active matter Microswimmers

来源：评论

学校读者我要写书评

暂无评论

Inferring missing edges in a graph from observed collective patterns

引用

Physical Review E 2022年第6期105卷 064610-064610页

作者： Selim Haj Ali Marc-Thorsten Hütt Department of Life Sciences and Chemistry Jacobs University Bremen D-28759 Bremen Germany

Many real-life networks are incomplete. Dynamical observations can allow estimating missing edges. Such procedures, often summarized under the term ‘network inference’, typically evaluate the statistical correlations among pairs of nodes to determine connectivity. Here, we offer an alternative approach: completing an incomplete network by observing its collective behavior. We illustrate this approach for the case of patterns emerging in reaction-diffusion systems on graphs, where collective behaviors can be associated with eigenvectors of the network's Laplacian matrix. Our method combines a partial spectral decomposition of the network's Laplacian matrix with eigenvalue assignment by matching the patterns to the eigenvectors of the incomplete graph. We show that knowledge of a few collective patterns can allow the prediction of missing edges and that this result holds across a range of network architectures. We present a numerical case study using activator-inhibitor dynamics and we illustrate that the main requirement for the observed patterns is that they are not confined to subsets of nodes, but involve the whole network.

关键词： Collective dynamics complex systems Computational complexity Network structure Pattern formation patterns in complex systems Self-organization

来源：评论

学校读者我要写书评

暂无评论

Cellular automata approach to modeling self-organized periodic patterns in nanoparticle-doped liquid crystals

引用

Physical Review E 2022年第4期106卷 044705-044705页

作者： Piotr Fronczak Agata Fronczak Piotr Lesiak Karolina Bednarska Wiktor Lewandowski Michał Wójcik Faculty of Physics Warsaw University of Technology Koszykowa 75 PL-00-662 Warszawa Poland Faculty of Chemistry University of Warsaw ul. Pasteura 1 PL-02-093 Warszawa Poland

Elementary cellular automata provide one of the simplest ways to generally describe the phenomena of pattern formation. However, they are considered too simple to be able to describe in detail the more complex phenomena occurring in real experimental systems. In this article, we demonstrate the an application of these methods to optical systems, providing an understanding of the mechanisms behind the formation of periodic patterns in nanoparticle-doped liquid crystals. Our extremely simplified model also explains the observed linear relationship between periodicity and system size.

关键词： Emergence of patterns Pattern formation patterns in complex systems Liquid crystals Cellular automata

来源：评论

学校读者我要写书评

暂无评论

Large-Scale patterns in a Minimal Cognitive Flocking Model: Incidental Leaders, Nematic patterns, and Aggregates

引用

Physical Review Letters 2016年第24期117卷 248001-248001页

作者： Lucas Barberis Fernando Peruani Université Côte d’Azur Laboratoire J.A. Dieudonné UMR 7351 CNRS Parc Valrose F-06108 Nice Cedex 02 France IFEG FaMAF CONICET UNC X5000HUA Córdoba Argentina

We study a minimal cognitive flocking model, which assumes that the moving entities navigate using the available instantaneous visual information exclusively. The model consists of active particles, with no memory, that interact by a short-ranged, position-based, attractive force, which acts inside a vision cone (VC), and lack velocity-velocity alignment. We show that this active system can exhibit—due to the VC that breaks Newton’s third law—various complex, large-scale, self-organized patterns. Depending on parameter values, we observe the emergence of aggregates or millinglike patterns, the formation of moving—locally polar—files with particles at the front of these structures acting as effective leaders, and the self-organization of particles into macroscopic nematic structures leading to long-ranged nematic order. Combining simulations and nonlinear field equations, we show that position-based active models, as the one analyzed here, represent a new class of active systems fundamentally different from other active systems, including velocity-alignment-based flocking systems. The reported results are of prime importance in the study, interpretation, and modeling of collective motion patterns in living and nonliving active systems.

关键词： Collective behavior Flocking patterns in complex systems Swarming Theories of collective dynamics & active matter

来源：评论

学校读者我要写书评

暂无评论

Determining conduction patterns on a sparse electrode grid: Implications for the analysis of clinical arrhythmias

引用

Physical Review E 2016年第5期94卷 050401(R)-050401(R)页

作者： David Vidmar Sanjiv M. Narayan David E. Krummen Wouter-Jan Rappel Department of Physics University of California San Diego La Jolla California 92903 USA

We present a general method of utilizing bioelectric recordings from a spatially sparse electrode grid to compute a dynamic vector field describing the underlying propagation of electrical activity. This vector field, termed the wave-front flow field, permits quantitative analysis of the magnitude of rotational activity (vorticity) and focal activity (divergence) at each spatial point. We apply this method to signals recorded during arrhythmias in human atria and ventricles using a multipolar contact catheter and show that the flow fields correlate with corresponding activation maps. Further, regions of elevated vorticity and divergence correspond to sites identified as clinically significant rotors and focal sources where therapeutic intervention can be effective. These flow fields can provide quantitative insights into the dynamics of normal and abnormal conduction in humans and could potentially be used to enhance therapies for cardiac arrhythmias.

关键词： Action potential propagation Cardiac dynamics patterns in complex systems

来源：评论

学校读者我要写书评

暂无评论

Noncapillary Wave Dynamics due to Interfacial Coupling with Plasma patterns at a Liquid Surface

引用

Physical Review Letters 2024年第10期133卷 105301页

作者： Oles Dubrovski Jinyu Yang Felipe Veloso David B. Go Hsueh-Chia Chang Paul Rumbach Department of Aerospace and Mechanical Engineering Instituto de Física Department of Chemical and Biomolecular Engineering

We identify a new class of surface waves that arise at a plasma-liquid interface due to resonant coupling between discrete plasma pattern modes and a continuum of interfacial liquid surface wave modes. A wave mode is selected due to localized excitation by the plasma, and standing waves result when waves excited from different locations interact. These waves propagate with a slower phase velocity than traditional capillary waves, but exhibit the same damping behavior with respect to liquid viscosity. Surface tension does not appear to play a significant role. We propose a curvature-dependent Maxwell pressure mechanism to explain these nondispersive interfacial waves in the presence of plasma.

关键词： Capillary waves Electrochemistry Electrohydrodynamic effects Electrokinetic flows Glow & corona plasma discharges patterns in complex systems Plasma instabilities Plasma ionization Plasma stability Scaling laws of complex systems

来源：评论

学校读者我要写书评

暂无评论

Stability of milling patterns in self-propelled swarms on surfaces

引用

Physical Review E 2020年第2期102卷 022212-022212页

作者： Jason Hindes Victoria Edwards Sayomi Kamimoto George Stantchev Ira B. Schwartz U.S. Naval Research Laboratory Washington D.C. 20375 USA Department of Mathematics George Mason University Fairfax Virginia 22030 USA

In some physical and biological swarms, agents effectively move and interact along curved surfaces. The associated constraints and symmetries can affect collective-motion patterns, but little is known about pattern stability in the presence of surface curvature. To make progress, we construct a general model for self-propelled swarms moving on surfaces using Lagrangian mechanics. We find that the combination of self-propulsion, friction, mutual attraction, and surface curvature produce milling patterns where each agent in a swarm oscillates on a limit cycle with different agents splayed along the cycle such that the swarm's center-of-mass remains stationary. In general, such patterns loose stability when mutual attraction is insufficient to overcome the constraint of curvature, and we uncover two broad classes of stationary milling-state bifurcations. In the first, a spatially periodic mode undergoes a Hopf bifurcation as curvature is increased, which results in unstable spatiotemporal oscillations. This generic bifurcation is analyzed for the sphere and demonstrated numerically for several surfaces. In the second, a saddle-node-of-periodic orbits occurs in which stable and unstable milling states collide and annihilate. The latter is analyzed for milling states on cylindrical surfaces. Our results contribute to the general understanding of swarm pattern formation and stability in the presence of surface curvature and may aid in designing robotic swarms that can be controlled to move over complex surfaces and terrains.

关键词： Bifurcations Collective behavior Mathematical physics Nonequilibrium statistical mechanics Pattern formation patterns in complex systems Self-organized systems Swarming Synchronization

来源：评论

学校读者我要写书评

暂无评论

Classification of emerging patterns in self-assembled two-dimensional magnetic lattices

引用

Physical Review E 2021年第4期104卷 044902-044902页

作者： Ehsan Norouzi Audrey A. Watkins Osama R. Bilal Wave Engineering through eXtreme & Intelligent matTEr Laboratory Department of Mechanical Engineering University of Connecticut Storrs Connecticut 06269 USA

Self-assembled granular materials can be utilized in many applications such as shock absorption and energy harvesting. Such materials are inherently discrete with an easy path to tunability through external applied forces such as stress or by adding more elements to the system. However, the self-assembly process is statistical in nature with no guarantee for repeatability, stability, or order of emergent final assemblies. Here we study both numerically and experimentally the two-dimensional self-assembly of free-floating disks with repulsive magnetic potentials confined to a boundary with embedded permanent magnets. Six different types of disks and seven boundary shapes are considered. An agent-based model is developed to predict the self-assembled patterns for any given disk type, boundary, and number of disks. The validity of the model is experimentally verified. While the model converges to a physical solution, these solutions are not always unique and depend on the initial position of the disks. The emerging patterns are classified into monostable patterns (i.e., stable patterns that emerge regardless of the initial conditions) and multistable patterns. We also characterize the emergent order and crystallinity of the emerging patterns. The developed model along with the self-assembly nature of the system can be key in creating re-programmable materials with exceptional nonlinear properties.

关键词： Emergence of patterns patterns in complex systems Self-assembly Pattern formation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：