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Physical computing: a category theoretic perspective on physical computation and system compositionality 物理计算:从范畴论角度看物理计算和系统组合性
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-07-16 DOI: 10.1088/2632-072x/ad6051
Nima Dehghani and Gianluca Caterina
This paper introduces a category theory-based framework to redefine physical computing in light of advancements in quantum computing and non-standard computing systems. By integrating classical definitions within this broader perspective, the paper rigorously recontextualizes what constitutes physical computing devices and processes. It demonstrates how the compositional nature and relational structures of physical computing systems can be coherently formalized using category theory. This approach not only encapsulates recent formalisms in physical computing but also offers a structured method to explore the dynamic interactions within these systems.
本文介绍了一个基于范畴理论的框架,根据量子计算和非标准计算系统的进步重新定义物理计算。通过将经典定义纳入这一更广阔的视角,本文对物理计算设备和过程的构成进行了严格的重新定义。它展示了物理计算系统的组成性质和关系结构如何能够利用范畴理论进行连贯的形式化。这种方法不仅囊括了物理计算领域的最新形式主义,还为探索这些系统内部的动态互动提供了结构化方法。
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引用次数: 0
Tuning the activation function to optimize the forecast horizon of a reservoir computer 调整激活函数以优化水库计算机的预测范围
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-07-11 DOI: 10.1088/2632-072x/ad5e55
L A Hurley, J G Restrepo and S E Shaheen
Reservoir computing is a machine learning framework where the readouts from a nonlinear system (the reservoir) are trained so that the output from the reservoir, when forced with an input signal, reproduces a desired output signal. A common implementation of reservoir computers (RCs) is to use a recurrent neural network as the reservoir. The design of this network can have significant effects on the performance of the RC. In this paper we study the effect of the node activation function on the ability of RCs to learn and predict chaotic time series. We find that the Forecast Horizon (FH), the time during which the reservoir’s predictions remain accurate, can vary by an order of magnitude across a set of 16 activation functions used in machine learning. By using different functions from this set, and by modifying their parameters, we explore whether the entropy of node activation levels or the curvature of the activation functions determine the predictive ability of the reservoirs. We find that the FH is low when the activation function is used in a region where it has low curvature, and a positive correlation between curvature and FH. For the activation functions studied we find that the largest FH generally occurs at intermediate levels of the entropy of node activation levels. Our results show that the performance of RCs is very sensitive to the activation function shape. Therefore, modifying this shape in hyperparameter optimization algorithms can lead to improvements in RC performance.
蓄水池计算是一种机器学习框架,通过对非线性系统(蓄水池)的读数进行训练,使蓄水池的输出在输入信号的作用下重现所需的输出信号。水库计算机 (RC) 的常见实现方式是使用递归神经网络作为水库。该网络的设计会对 RC 的性能产生重大影响。本文研究了节点激活函数对 RC 学习和预测混沌时间序列能力的影响。我们发现,在机器学习中使用的一组 16 个激活函数中,预测水平线(FH),即储层预测保持准确的时间,会有数量级的变化。通过使用这组函数中的不同函数并修改其参数,我们探索了节点激活水平的熵或激活函数的曲率是否决定了水库的预测能力。我们发现,当在曲率较低的区域使用激活函数时,FH 值较低,而且曲率与 FH 值之间呈正相关。对于所研究的激活函数,我们发现最大的 FH 通常出现在节点激活水平熵的中间水平。我们的结果表明,RC 的性能对激活函数的形状非常敏感。因此,在超参数优化算法中修改这种形状可以提高 RC 性能。
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引用次数: 0
Dynamics and sorting of run-and-tumble particles in fluid flows with transport barriers 有传输障碍的流体流动中翻滚颗粒的动力学和分拣
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-07-10 DOI: 10.1088/2632-072x/ad5bb2
Rafael Dias Vilela, Alfredo J Grados and Jean-Régis Angilella
We investigate the dynamics of individual run-and-tumble particles in a convective flow which is a prototype of fluid flows with transport barriers. We consider the most prevalent case of swimmers denser than the background fluid. As a result of gravity and the effects of the carrying flow, in the absence of swimming the particles either sediment or remain in a convective cell. When run-and-tumble also takes place, the particles may move to upper convective cells. We derive analytically the probability of uprise. Since that probability in a given fluid flow can vary strongly across species, our findings inspire a purely dynamical mechanism for species extraction in the dilute regime. Numerical simulations support our analytical predictions and demonstrate that a judicious choice of the fluid flow’s parameters can lead to particle sorting with an arbitrary degree of purity.
我们研究了对流中单个奔跑和翻滚粒子的动力学,对流是具有传输障碍的流体流动的原型。我们考虑了最常见的游动粒子密度大于背景流体密度的情况。由于重力和携带流的影响,在没有游动的情况下,颗粒要么沉积,要么停留在对流单元中。当发生奔跑和翻滚时,颗粒可能会移动到上层对流单元。我们通过分析得出上浮概率。由于在给定的流体流动中,不同物种的上浮概率会有很大差异,我们的发现启发了稀释体系中物种萃取的纯动力学机制。数值模拟支持我们的分析预测,并证明对流体流动参数的明智选择可以实现任意纯度的粒子分选。
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引用次数: 0
Modeling natural resources exploitation in low-information environments 低信息环境下的自然资源开发建模
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-07-04 DOI: 10.1088/2632-072x/ad5cb9
Silvia Muñoz-Álvarez, Carlos Gracia-Lázaro and Yamir Moreno
The sustainable exploitation of natural resources constitutes a real-world problem of interest for many fields. In this work, we study those situations in which the exploiting agents have information about the state of the resource and their own benefits and costs but not about the behavior or performance of the rest of the agents. Cognitive Hierarchy Theory provides a framework for those low-information scenarios by focusing on the assumptions that agents make about other individuals’ behavior. Motivated by this theory, we introduce a theoretical agent-based model in which agents exhibit varying degrees of rationalization when exploiting the resource, and this resource’s evolution is driven by a differential equation that mirrors the dynamics of real-world resource growth. Our results show that, although most regimes imply depletion, higher benefits and sustainability are obtained when agents assume overexploitation by the rest and try to compensate for it. Furthermore, many exploiting agents and a long-term perspective also involve a better resource state, reaching the optimal exploitation level when all these factors come together.
自然资源的可持续开发是许多领域关注的现实问题。在这项工作中,我们研究的是这样一种情况,即开采者拥有关于资源状况、自身收益和成本的信息,但不了解其他开采者的行为或表现。认知层次理论(Cognitive Hierarchy Theory)通过关注代理对其他个体行为的假设,为这些低信息量情景提供了一个框架。受这一理论的启发,我们引入了一个基于代理的理论模型,在该模型中,代理在开发资源时表现出不同程度的合理化,而这种资源的演变是由一个反映现实世界资源增长动态的微分方程驱动的。我们的研究结果表明,尽管大多数制度都意味着资源枯竭,但当代理假定其他代理过度开发资源并试图对其进行补偿时,就会获得更高的收益和可持续性。此外,许多开发代理人和长期视角也会带来更好的资源状态,当所有这些因素结合在一起时,就会达到最佳开发水平。
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引用次数: 0
The spectral boundary of block structured random matrices 块状结构随机矩阵的谱边界
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-07-04 DOI: 10.1088/2632-072x/ad5cba
Nirbhay Patil, Fabián Aguirre-López and Jean-Philippe Bouchaud
Economic and ecological models can be extremely complex, with a large number of agents/species each featuring multiple interacting dynamical quantities. In an attempt to understand the generic stability properties of such systems, we define and study an interesting new matrix ensemble with extensive correlations, generalising the elliptic ensemble. We determine analytically the boundary of its eigenvalue spectrum in the complex plane, as a function of the correlations determined by the model at hand. We solve numerically our equations in several cases of interest, and show that the resulting spectra can take a surprisingly wide variety of shapes.
经济和生态模型可能极其复杂,其中包含大量的代理/物种,每个代理/物种都具有多个相互作用的动态量。为了理解这类系统的一般稳定性,我们定义并研究了一种有趣的新矩阵集合,它具有广泛的相关性,是椭圆集合的一般化。我们通过分析确定了复平面上特征值谱的边界,它是由手头模型确定的相关性的函数。我们用数值方法求解了几种相关情况下的方程,结果表明所得到的频谱具有令人惊讶的各种形状。
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引用次数: 0
Exploring the interplay of technology, pro-family and prosocial behavior in settlement formation 探索定居形成过程中技术、亲家庭和亲社会行为的相互作用
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-06-20 DOI: 10.1088/2632-072x/ad577f
Carlos Gracia-Lázaro, Alexis R Hernández, Felipe Maciel-Cardoso and Yamir Moreno
We present an agent-based model that explores the intricate relationship between pro-family and prosocial behaviors and their impact on settlement formation. The objective is to investigate how the technological level and various constraints influence the transition from pro-family to prosocial behavior. The model incorporates factors such as the specialization requirements of the technology, societal tolerance, and dynamic interactions within a synthetic population, where individuals may prioritize either their family or their own settlement. Agents’ fitness is determined by two components: the proportion of pro-family agents within their family and the fraction of prosocial agents in their settlement, along with its size. Our findings reveal that (i) the technological level drives the transition from pro-family to prosocial behavior, and (ii) the developmental requirements of the technology shape the smoothness of this transition, ranging from abrupt to gradual. These results emphasize the significance of considering the interplay between the technological level, the nature of the technology, and cultural influences when examining settlement patterns and the dynamics of pro-family and prosocial behaviors in human societies.
我们提出了一个基于代理的模型,探讨亲家庭行为和亲社会行为之间错综复杂的关系及其对定居形成的影响。目的是研究技术水平和各种限制因素如何影响从亲家庭行为到亲社会行为的过渡。该模型结合了技术的专业化要求、社会容忍度以及合成种群内的动态互动等因素,在合成种群中,个体可能会优先考虑自己的家庭或自己的定居点。个体的适应性由两部分决定:其家庭中亲家庭个体的比例和其聚居地中亲社会个体的比例,以及聚居地的规模。我们的研究结果表明:(i) 技术水平推动了从亲家庭行为到亲社会行为的过渡;(ii) 技术的发展要求决定了这一过渡的平稳程度,从突然到渐进不等。这些结果表明,在研究人类社会的定居模式以及亲家庭和亲社会行为的动态时,考虑技术水平、技术性质和文化影响之间的相互作用具有重要意义。
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引用次数: 0
Hopf bifurcations of twisted states in phase oscillators rings with nonpairwise higher-order interactions 具有非成对高阶相互作用的相位振荡器环中扭曲态的霍普夫分岔
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-06-19 DOI: 10.1088/2632-072x/ad5635
Christian Bick, Tobias Böhle and Oleh E Omel’chenko
Synchronization is an essential collective phenomenon in networks of interacting oscillators. Twisted states are rotating wave solutions in ring networks where the oscillator phases wrap around the circle in a linear fashion. Here, we analyze Hopf bifurcations of twisted states in ring networks of phase oscillators with nonpairwise higher-order interactions. Hopf bifurcations give rise to quasiperiodic solutions that move along the oscillator ring at nontrivial speed. Because of the higher-order interactions, these emerging solutions may be stable. Using the Ott–Antonsen approach, we continue the emergent solution branches which approach anti-phase type solutions (where oscillators form two clusters whose phase is π apart) as well as twisted states with a different winding number.
在相互作用的振荡器网络中,同步是一种重要的集体现象。扭曲态是环形网络中的旋转波解,其中振荡器相位以线性方式环绕圆周。在这里,我们分析了具有非成对高阶相互作用的相位振荡器环形网络中扭曲状态的霍普夫分岔。霍普夫分岔会产生沿振荡器环以非对偶速度移动的准周期解。由于高阶相互作用,这些新出现的解可能是稳定的。利用奥特-安东森方法,我们继续研究新出现的解分支,这些分支接近反相型解(振荡器形成两个相位相差 π 的簇群)以及具有不同绕组数的扭曲状态。
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引用次数: 0
Multifractal analysis of the perimeters of glaciers in the Svalbard Archipelago 斯瓦尔巴群岛冰川周缘的多分形分析
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-06-16 DOI: 10.1088/2632-072x/ad5263
Marina Carpineti, Valerio Lupo Sepe, Antonella Senese, Giacomo Traversa, Guglielmina A Diolaiuti and Alberto Vailati
The investigation of the evolution of glaciers largely relies on the characterisation of extensive quantities like their mass, area, and perimeter. In this work we use fractal and multifractal analysis to investigate the non-extensive structural properties of the perimeters of glaciers in the Svalbard Archipelago. We show that the perimeters of the glaciers exhibit a fractal structure with a fractal dimension , independently from the area of the glaciers. The investigation of the multifractal properties of the perimeters shows that small glaciers exhibit a more pronounced multifractal structure, as witnessed by the larger range of generalized dimensions Dq needed to characterise them. The range ΔDq of generalised dimensions required to characterise the multifractal perimeter of a glacier exhibits a power-law dependence with exponent −1.2 from the area, and represents a non-extensive parameter able to grab effectively the dependence of the multifractal structure of the perimeters on the size of glaciers. The comparison with similar results obtained in a previous study performed on glaciers in the Lombardy region of the Italian Alps confirms the robustness of the analysis performed, which does not appear to be affected by the morphology of the substrate or by climate conditions.
对冰川演变的研究在很大程度上依赖于对其质量、面积和周长等广义量的描述。在这项研究中,我们利用分形和多分形分析方法研究了斯瓦尔巴群岛冰川周缘的非广义结构特性。我们的研究表明,冰川周缘呈现出分形结构,其分形维度与冰川面积无关。对冰川周缘多分形特性的研究表明,小冰川表现出更明显的多分形结构,这一点可以从表征小冰川所需的更大范围的广义维数 Dq 中得到证明。表征冰川多分形周长所需的广义尺寸范围ΔDq与面积呈指数为-1.2的幂律关系,是一个非广义参数,能够有效地反映冰川周长的多分形结构与冰川大小的关系。与之前对意大利阿尔卑斯山伦巴第地区冰川进行的一项研究中获得的类似结果进行比较,证实了所做分析的稳健性,分析结果似乎不受基底形态或气候条件的影响。
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引用次数: 0
Lyapunov analysis of data-driven models of high dimensional dynamics using reservoir computing: Lorenz-96 system and fluid flow 利用储层计算对数据驱动的高维动力学模型进行李亚普诺夫分析:洛伦兹-96 系统和流体流动
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-06-16 DOI: 10.1088/2632-072x/ad5264
Miki U Kobayashi, Kengo Nakai and Yoshitaka Saiki
We computed the Lyapunov spectrum and finite-time Lyapunov exponents of a data-driven model constructed using reservoir computing. This analysis was performed for two dynamics that exhibit a highly dimensionally unstable structure. We focused on the reconstruction of heterochaotic dynamics, which are characterized by the coexistence of different numbers of unstable dimensions. This was achieved by computing fluctuations in the number of positive finite-time Lyapunov exponents.
我们计算了利用水库计算构建的数据驱动模型的李亚普诺夫谱和有限时间李亚普诺夫指数。该分析是针对两个表现出高维度不稳定结构的动力学模型进行的。我们的重点是重建异相动力学,其特点是不同数量的不稳定维度并存。这是通过计算正有限时间李亚普诺夫指数的波动来实现的。
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引用次数: 0
Economic complexity and the sustainability transition: a review of data, methods, and literature 经济复杂性和可持续性转型:数据、方法和文献综述
IF 2.7 Q1 MATHEMATICS, INTERDISCIPLINARY APPLICATIONS Pub Date : 2024-06-16 DOI: 10.1088/2632-072x/ad4f3d
Bernardo Caldarola, Dario Mazzilli, Lorenzo Napolitano, Aurelio Patelli and Angelica Sbardella
Economic Complexity (EC) methods have gained increasing popularity across fields and disciplines. In particular, the EC toolbox has proved particularly promising in the study of complex and interrelated phenomena, such as the transition towards a more sustainable economy. Using the EC approach, scholars have been investigating the relationship between EC and sustainability, and identifying the distinguishing characteristics of green activities and to assess the readiness of productive and technological structures for the sustainability transition. This article proposes to review and summarize the data, methods, and empirical literature that are relevant to the study of the sustainability transition from an EC perspective. We review three distinct but connected blocks of literature on EC and environmental sustainability. First, we survey the evidence linking measures of EC to indicators related to environmental sustainability. Second, we review articles that strive to assess the green competitiveness of productive systems. Third, we examine evidence on green technological development and its connection to non-green knowledge bases. Finally, we summarize the findings for each block, while identifying criticalities and avenues for further research in this recent and growing body of empirical literature.
经济复杂性(Economic Complexity,EC)方法在各个领域和学科越来越受欢迎。特别是,事实证明,经济复杂性工具箱在研究复杂和相互关联的现象(如向更可持续的经济转型)方面特别有前途。学者们一直在使用生态经济方法研究生态经济与可持续发展之间的关系,确定绿色活动的显著特征,并评估生产和技术结构是否为可持续发展转型做好了准备。本文拟回顾和总结与从欧共体角度研究可持续性转型相关的数据、方法和实证文献。我们回顾了有关欧共体和环境可持续性的三组不同但相互关联的文献。首先,我们调查了将欧共体措施与环境可持续性相关指标联系起来的证据。其次,我们回顾了致力于评估生产系统绿色竞争力的文章。第三,我们研究了绿色技术发展及其与非绿色知识基础之间联系的证据。最后,我们总结了每个部分的研究结果,同时指出了最近不断增加的实证文献中的关键问题和进一步研究的途径。
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引用次数: 0
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Journal of Physics Complexity
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