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The degree of economic development pattern of economy J. Phys. Complex Pub Date : 2024-04-16 Yuan-Yuan Guo, Xiao-Pu Han
In this article, we explore the concept and measurement of the degree of economic development pattern (DEDP) of economy, which refers to the extent to which the development of an economy can serve as a reference for other economies. Utilizing 76 macroeconomic indicators across 217 economies, the economic development paths in a standardized space of economy is compared to identify variations in DEDP
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Taming travel time fluctuations through adaptive stop pooling J. Phys. Complex Pub Date : 2024-04-10 Charlotte Lotze, Philip Marszal, Malte Schröder, Marc Timme
Ride sharing services combine trips of multiple users in the same vehicle and may provide more sustainable transport than private cars. As mobility demand varies during the day, the travel times experienced by passengers may substantially vary as well, making the service quality unreliable. We show through model simulations that such travel time fluctuations may be drastically reduced by stop pooling
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Higher-order connection Laplacians for directed simplicial complexes J. Phys. Complex Pub Date : 2024-03-28 Xue Gong, Desmond J Higham, Konstantinos Zygalakis, Ginestra Bianconi
Higher-order networks encode the many-body interactions existing in complex systems, such as the brain, protein complexes, and social interactions. Simplicial complexes are higher-order networks that allow a comprehensive investigation of the interplay between topology and dynamics. However, simplicial complexes have the limitation that they only capture undirected higher-order interactions while in
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On the information-theoretic formulation of network participation J. Phys. Complex Pub Date : 2024-03-27 Pavle Cajic, Dominic Agius, Oliver M Cliff, James M Shine, Joseph T Lizier, Ben D Fulcher
The participation coefficient is a widely used metric of the diversity of a node’s connections with respect to a modular partition of a network. An information-theoretic formulation of this concept of connection diversity, referred to here as participation entropy, has been introduced as the Shannon entropy of the distribution of module labels across a node’s connected neighbors. While diversity metrics
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Reconstructing supply networks J. Phys. Complex Pub Date : 2024-03-25 Luca Mungo, Alexandra Brintrup, Diego Garlaschelli, François Lafond
Network reconstruction is a well-developed sub-field of network science, but it has only recently been applied to production networks, where nodes are firms and edges represent customer-supplier relationships. We review the literature that has flourished to infer the topology of these networks by partial, aggregate, or indirect observation of the data. We discuss why this is an important endeavour
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Global synchronization on time-varying higher-order structures J. Phys. Complex Pub Date : 2024-03-21 Md Sayeed Anwar, Dibakar Ghosh, Timoteo Carletti
Synchronization has received a lot of attention from the scientific community for systems evolving on static networks or higher-order structures, such as hypergraphs and simplicial complexes. In many relevant real-world applications, the latter are not static but do evolve in time, in this work we thus discuss the impact of the time-varying nature of higher-order structures in the emergence of global
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Nonuniformly twisted states and traveling chimeras in a system of nonlocally coupled identical phase oscillators J. Phys. Complex Pub Date : 2024-03-13 L A Smirnov, M I Bolotov, A Pikovsky
We explore the model of a population of nonlocally coupled identical phase oscillators on a ring (Abrams and Strogatz 2004 Phys. Rev. Lett. 93 174102) and describe traveling patterns. In the continuous in space formulation, we find families of traveling wave solutions for left-right symmetric and asymmetric couplings. Only the simplest of these waves are stable, which is confirmed by numerical simulations
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Mobility restrictions in response to local epidemic outbreaks in rock-paper-scissors models J. Phys. Complex Pub Date : 2024-03-08 J Menezes
We study a three-species cyclic model whose organisms are vulnerable to contamination with an infectious disease which propagates person-to-person. We consider that individuals of one species perform a self-preservation strategy by reducing the mobility rate to minimise infection risk whenever an epidemic outbreak reaches the neighbourhood. Running stochastic simulations, we quantify the changes in
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Local sign stability and its implications for spectra of sparse random graphs and stability of ecosystems J. Phys. Complex Pub Date : 2024-03-06 Pietro Valigi, Izaak Neri, Chiara Cammarota
We study the spectral properties of sparse random graphs with different topologies and type of interactions, and their implications on the stability of complex systems, with particular attention to ecosystems. Specifically, we focus on the behaviour of the leading eigenvalue in different type of random matrices (including interaction matrices and Jacobian-like matrices), relevant for the assessment
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Detection of limit cycle signatures of El Niño in models and observations using reservoir computing J. Phys. Complex Pub Date : 2024-03-06 Francesco Guardamagna, Claudia Wieners, Xianghui Fang, Henk A Dijkstra
While the physics of the El Niño–Southern Oscillation (ENSO) phenomenon in the Tropical Pacific is quite well understood, there is still debate on several more fundamental aspects. The focus of this paper is on one of these issues that deals with whether ENSO variability, within the recharge-discharge oscillator theory arising from a stochastic Hopf bifurcation, is subcritical or supercritical. Using
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Pathways to discontinuous transitions in interacting contagion dynamics J. Phys. Complex Pub Date : 2024-02-28 Santiago Lamata-Otín, Jesús Gómez-Gardeñes, David Soriano-Paños
Yet often neglected, dynamical interdependencies between concomitant contagion processes can alter their intrinsic equilibria and bifurcations. A particular case of interest for disease control is the emergence of discontinuous transitions in epidemic dynamics coming from their interactions with other simultaneous processes. To address this problem, here we propose a framework coupling a standard epidemic
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Transfer operators on graphs: spectral clustering and beyond J. Phys. Complex Pub Date : 2024-02-23 Stefan Klus, Maia Trower
Graphs and networks play an important role in modeling and analyzing complex interconnected systems such as transportation networks, integrated circuits, power grids, citation graphs, and biological and artificial neural networks. Graph clustering algorithms can be used to detect groups of strongly connected vertices and to derive coarse-grained models. We define transfer operators such as the Koopman
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Effects of topological structure and destination selection strategies on agent dynamics in complex networks J. Phys. Complex Pub Date : 2024-02-23 Satori Tsuzuki, Daichi Yanagisawa, Eri Itoh, Katsuhiro Nishinari
We analyzed agent behavior in complex networks: Barabási–Albert, Erdos–Rényi, and Watts–Strogatz models under the following rules: agents (a) randomly select a destination among adjacent nodes; (b) exclude the most congested adjacent node as a potential destination and randomly select a destination among the remaining nodes; or (c) select the sparsest adjacent node as a destination. We focused on small
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The role of intervention mechanisms on a self-organized system: dynamics of a sandpile with site reinforcement J. Phys. Complex Pub Date : 2024-02-22 P B Sy, R C Batac
We revisit the sandpile model and examine the effect of introducing site-dependent thresholds that increase over time based on the generated avalanche size. This is inspired by the simplest means of introducing stability into a self-organized system: the locations of collapse are repaired and reinforced. Statistically, for the case of finite driving times, we observe that the site-dependent reinforcements
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Stochastic-like characteristics of arithmetic dynamical systems: the Collatz hailstone sequences J. Phys. Complex Pub Date : 2024-02-19 J G Polli, E P Raposo, G M Viswanathan, M G E da Luz
The numerical hailstone sequences, or orbits, generated by the Collatz map have been disclosed to present relevant features commonly associated with complex systems. It is so despite the extreme simplicity of the arithmetic dynamical system iteration rule. Indeed, for a positive integer n, the Collatz map f reads f(n)=n/2 ( f(n)=3n+1 ) for n even (odd). Seeking to elucidate this surprising fact, here
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Equivalence between the Fitness-Complexity and the Sinkhorn-Knopp algorithms J. Phys. Complex Pub Date : 2024-02-16 D Mazzilli, M S Mariani, F Morone, A Patelli
We uncover the connection between the Fitness-Complexity algorithm, developed in the economic complexity field, and the Sinkhorn–Knopp algorithm, widely used in diverse domains ranging from computer science and mathematics to economics. Despite minor formal differences between the two methods, both converge to the same fixed-point solution up to normalization. The discovered connection allows us to
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Strength of minority ties: the role of homophily and group composition in a weighted social network J. Phys. Complex Pub Date : 2024-02-16 José R Nicolás-Carlock, Denis Boyer, Sandra E Smith-Aguilar, Gabriel Ramos-Fernández
Homophily describes a fundamental tie-formation mechanism in social networks in which connections between similar nodes occur at a higher rate than among dissimilar ones. In this article, we present an extension of the weighted social network (WSN) model that, under an explicit homophily principle, quantifies the emergence of attribute-dependent properties of a social system. To test our model, we
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Classification of stochastic processes based on deep learning J. Phys. Complex Pub Date : 2024-02-15 Shamsan A Al-Murisi, Xiangong Tang, Weihua Deng
Stochastic processes model the time evolution of fluctuation phenomena widely observed in physics, chemistry, biology, and even social science. Typical examples include the dynamics of molecular interactions, cellular signalling, animal feeding, disease transmission, financial market fluctuation, and climate change. We create three datasets based on the codes obtained from the published article; the
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The complexity of climate change mitigation: an experiment with large groups J. Phys. Complex Pub Date : 2024-02-14 Antonio Alfonso, Pablo Brañas-Garza, Antonio Cabrales, Angel Sánchez
We have studied the problem of climate change mitigation in large groups by means of a series of experiments with 1785 people. Our participants included both young university students and people of relevance in different organizations, in particular, those attending the presentation of the annual report on innovation by Fundación COTEC (Spain). In the experiment, the participants, distributed in groups
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Filtering higher-order datasets J. Phys. Complex Pub Date : 2024-02-13 Nicholas W Landry, Ilya Amburg, Mirah Shi, Sinan G Aksoy
Many complex systems often contain interactions between more than two nodes, known as higher-order interactions, which can change the structure of these systems in significant ways. Researchers often assume that all interactions paint a consistent picture of a higher-order dataset’s structure. In contrast, the connection patterns of individuals or entities in empirical systems are often stratified
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Analysis of the structural complexity of Crab Nebula observed at radio frequency using a multifractal approach J. Phys. Complex Pub Date : 2024-01-29 Athokpam Langlen Chanu, Pravabati Chingangbam, Fazlu Rahman, R K Brojen Singh, Preeti Kharb
The Crab Nebula is an astrophysical system that exhibits complex morphological patterns at different observing frequencies. We carry out a systematic investigation of the structural complexity of the nebula using publicly available imaging data at radio frequency. For the analysis, we use the well-known multifractal detrended fluctuation analysis in two dimensions. We find that radio data exhibit long-range
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Fault resilience in network of energy harvesters J. Phys. Complex Pub Date : 2024-01-25 Samana Pranesh, Sayan Gupta
Energy harvesters (EH) that scavenge energy from ambient environment are gaining popularity and are used for powering low demand devices on account of their low power outputs. Enhancement of the power is achieved through an array or network of identical EH. The focus of this study is on investigating how the network topology affects the harvesting efficiency per EH, using complex network theory. The
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Measuring an artificial intelligence language model’s trust in humans using machine incentives J. Phys. Complex Pub Date : 2024-01-24 Tim Johnson, Nick Obradovich
Will advanced artificial intelligence (AI) language models exhibit trust toward humans? Gauging an AI model’s trust in humans is challenging because—absent costs for dishonesty—models might respond falsely about trusting humans. Accordingly, we devise a method for incentivizing machine decisions without altering an AI model’s underlying algorithms or goal orientation and we employ the method in trust
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On the advances in machine learning and complex network measures to an EEG dataset from DMT experiments J. Phys. Complex Pub Date : 2024-01-22 Caroline L Alves, Manuel Ciba, Thaise G L de O. Toutain, Joel Augusto Moura Porto, Eduardo Pondé de Sena, Christiane Thielemann, Francisco A Rodrigues
There is a growing interest in the medical use of psychedelic substances, as preliminary studies using them for psychiatric disorders have shown positive results. In particular, one of these substances is N, N-dimethyltryptamine (DMT), an agonist serotonergic psychedelic that can induce profound alterations in the state of consciousness. In this work, we use an exploratory tool to reveal DMT-induced
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Rewiring driven evolution of quenched frustrated signed network J. Phys. Complex Pub Date : 2024-01-16 Sven Benjamin Kožić, Salvatore Marco Giampaolo, Vinko Zlatić
A framework for studying the behavior of a classically frustrated signed network in the process of random rewiring is developed. We describe jump probabilities for change in frustration and formulate a theoretical estimate in terms of the master equation. Stationary thermodynamic distribution and moments are derived from the master equation and compared to numerical simulations. Furthermore, an exact
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Epidemic modelling requires knowledge of the social network J. Phys. Complex Pub Date : 2024-01-09 Samuel Johnson
‘Compartmental models’ of epidemics are widely used to forecast the effects of communicable diseases such as COVID-19 and to guide policy. Although it has long been known that such processes take place on social networks, the assumption of ‘random mixing’ is usually made, which ignores network structure. However, ‘super-spreading events’ have been found to be power-law distributed, suggesting that
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Inferring comparative advantage via entropy maximization J. Phys. Complex Pub Date : 2023-12-28 Matteo Bruno, Dario Mazzilli, Aurelio Patelli, Tiziano Squartini, Fabio Saracco
We revise the procedure proposed by Balassa to infer comparative advantage, which is a standard tool in Economics to analyze specialization (of countries, regions, etc). Balassa’s approach compares a country’s export of a given product with what would be expected from a benchmark based on the total volumes of countries and product flows. Based on results in the literature, we show that implementing
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Computational phase transition signature in Gibbs sampling J. Phys. Complex Pub Date : 2023-12-27 Hariphan Philathong, Vishwanathan Akshay, Igor Zacharov, Jacob Biamonte
Gibbs sampling is fundamental to a wide range of computer algorithms. Such algorithms are set to be replaced by physics based processors—be it quantum or stochastic annealing devices—which embed problem instances and evolve a physical system into a low-energy ensemble to recover a probability distribution. At a critical constraint to variable ratio, satisfiability (SAT) problem instances exhibit a
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From statistical physics to social sciences: the pitfalls of multi-disciplinarity J. Phys. Complex Pub Date : 2023-12-08 Jean-Philippe Bouchaud
This is the English version of my inaugural lecture at Collège de France in 2021. I reflect on the difficulty of multi-disciplinary research, which often hinges on unexpected epistemological and methodological differences, for example about the scientific status of models. What is the purpose of a model? What are we ultimately trying to establish: rigorous theorems or ad-hoc calculation recipes; absolute
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Energy landscapes of some matching-problem ensembles J. Phys. Complex Pub Date : 2023-11-30 Till Kahlke, Alexander K Hartmann
The maximum-weight matching problem and the behavior of its energy landscape is numerically investigated. We apply a perturbation method adapted from the analysis of spin glasses. This method provides insight into the complexity of the energy landscape of different ensembles. Erdős–Rényi graphs and ring graphs with randomly added edges are considered, and two types of distributions for the random edge
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Zoo guide to network embedding J. Phys. Complex Pub Date : 2023-11-29 A Baptista, R J Sánchez-García, A Baudot, G Bianconi
Networks have provided extremely successful models of data and complex systems. Yet, as combinatorial objects, networks do not have in general intrinsic coordinates and do not typically lie in an ambient space. The process of assigning an embedding space to a network has attracted great interest in the past few decades, and has been efficiently applied to fundamental problems in network inference,
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Quantifying the hierarchical adherence of modular documents J. Phys. Complex Pub Date : 2023-11-23 Alexandre Benatti, Ana C M Brito, Diego R Amancio, Luciano da F Costa
Several natural and artificial structures are characterized by an intrinsic hierarchical organization. The present work describes a methodology for quantifying the degree of adherence between a given hierarchical template and a respective modular document (e.g. books or homepages with content organized into modules) organized as a respective content network. The original document, which in the case
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Encapsulation structure and dynamics in hypergraphs J. Phys. Complex Pub Date : 2023-11-22 Timothy LaRock, Renaud Lambiotte
Hypergraphs have emerged as a powerful modeling framework to represent systems with multiway interactions, that is systems where interactions may involve an arbitrary number of agents. Here we explore the properties of real-world hypergraphs, focusing on the encapsulation of their hyperedges, which is the extent that smaller hyperedges are subsets of larger hyperedges. Building on the concept of line
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Impact of tropical teleconnections on the long-range predictability of the atmosphere at midlatitudes: a reduced-order multi-scale model perspective J. Phys. Complex Pub Date : 2023-11-01 Stéphane Vannitsem
Teleconnections between the tropical and the extratropical climates are often considered as a potential source of long-term predictability at seasonal to decadal time scales in the extratropics. This claim is taken up in the present work by investigating the predictability of a coupled ocean–atmosphere extratropical model under a one-way forcing generated by a tropical model. Both models display a
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Assessing the impact of Byzantine attacks on coupled phase oscillators J. Phys. Complex Pub Date : 2023-10-26 Melvyn Tyloo
For many coupled dynamical systems, the interaction is the outcome of the measurement that each unit has of the others as e.g. in modern inverter-based power grids, autonomous vehicular platoons or swarms of drones, or it is the result of physical flows. Synchronization among all the components of these systems is of primal importance to avoid failures. The overall operational state of these systems
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Evolution of cooperation driven by sampling reward J. Phys. Complex Pub Date : 2023-10-23 Jiafeng Xiao, Linjie Liu, Xiaojie Chen, Attila Szolnoki
A social dilemma implies that individuals will choose the defection strategy to maximize their individual gains. Reward is a powerful motivator to promote the evolution of cooperation, thus addressing the social dilemma. Nevertheless, it is costly since we need to monitor all participants in the game. Inspired by these observations, we here propose an inexpensive protocol, a so-called sampling reward
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Unraveling the dynamics of wealth inequality and the impact on social mobility and health disparities J. Phys. Complex Pub Date : 2023-10-23 Caterina A M La Porta, Stefano Zapperi
Inequalities in wealth, income, access to food and healthcare have been rising worldwide in the past decades, approaching levels seen in the early 20th century. Here we study the relationships between wealth inequality and mobility for different segments of the population, comparing longitudinal surveys conducted in the USA and in Italy. The larger wealth inequality observed in the USA is reflected
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Disorder unleashes panic in bitcoin dynamics J. Phys. Complex Pub Date : 2023-10-17 Marco Alberto Javarone, Gabriele Di Antonio, Gianni Valerio Vinci, Raffaele Cristodaro, Claudio J Tessone, Luciano Pietronero
The behaviour of Bitcoin owners is reflected in the structure and the number of bitcoin transactions encoded in the Blockchain. Likewise, the behaviour of Bitcoin traders is reflected in the formation of bullish and bearish trends in the crypto market. In light of these observations, we wonder if human behaviour underlies some relationship between the Blockchain and the crypto market. To address this
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Modeling interdisciplinary interactions among physics, mathematics and computer science J. Phys. Complex Pub Date : 2023-10-13 Rima Hazra, Mayank Singh, Pawan Goyal, Bibhas Adhikari, Animesh Mukherjee
Interdisciplinarity has over the recent years have gained tremendous importance and has become one of the key ways of doing cutting edge research. In this paper we attempt to model the citation flow across three different fields—physics (PHY), mathematics (MA) and computer science (CS). For instance, is there a specific pattern in which these fields cite one another? We carry out experiments on a dataset
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Efficient network exploration by means of resetting self-avoiding random walkers J. Phys. Complex Pub Date : 2023-10-09 Gaia Colombani, Giulia Bertagnolli, Oriol Artime
The self-avoiding random walk (SARW) is a stochastic process whose state variable avoids returning to previously visited states. This non-Markovian feature has turned SARWs a powerful tool for modeling a plethora of relevant aspects in network science, such as network navigability, robustness and resilience. We analytically characterize self-avoiding random walkers that evolve on complex networks and
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Crossover phenomenon in adversarial attacks on voter model J. Phys. Complex Pub Date : 2023-09-25 Shogo Mizutaka
A recent study (Chiyomaru and Takemoto 2022 Phys. Rev. E 106 014301) considered adversarial attacks conducted to distort voter model dynamics in networks. This method intervenes in the interaction patterns of individuals and induces them to be in a target opinion state through a small perturbation ε. In this study, we investigate adversarial attacks on voter dynamics in random networks of finite size
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Group polarization, influence, and domination in online interaction networks: a case study of the 2022 Brazilian elections J. Phys. Complex Pub Date : 2023-09-13 Ruben Interian, Francisco A Rodrigues
The erosion of social cohesion and polarization is one of the topmost societal risks. In this work, we investigated the evolution of polarization, influence, and domination in online interaction networks using a large Twitter dataset collected before and during the 2022 Brazilian elections. From a theoretical perspective, we develop a methodology called d-modularity that allows discovering the contribution
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Smallworldness in hypergraphs J. Phys. Complex Pub Date : 2023-09-11 Tanu Raghav, Stefano Boccaletti, Sarika Jalan
Most real-world networks are endowed with the small-world property, by means of which the maximal distance between any two of their nodes scales logarithmically rather than linearly with their size. The evidence sparkled a wealth of studies trying to reveal possible mechanisms through which the pairwise interactions amongst the units of a network are structured in a way to determine such observed regularity
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Learning capacity and function of stochastic reaction networks J. Phys. Complex Pub Date : 2023-09-01 Abolfazl Ramezanpour, Alireza Mashaghi
Biochemical reaction networks are expected to encode an efficient representation of the function of cells in a variable environment. It is thus important to see how these networks do learn and implement such representations. The first step in this direction is to characterize the function and learning capabilities of basic artificial reaction networks. In this study, we consider multilayer networks
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Entropy of microcanonical finite-graph ensembles J. Phys. Complex Pub Date : 2023-08-25 Tatsuro Kawamoto
The entropy of random graph ensembles has gained widespread attention in the field of graph theory and network science. We consider microcanonical ensembles of simple graphs with prescribed degree sequences. We demonstrate that the mean-field approximations of the generating function using the Chebyshev–Hermite polynomials provide estimates for the entropy of finite-graph ensembles. Our estimate reproduces
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Exploring 3D community inconsistency in human chromosome contact networks J. Phys. Complex Pub Date : 2023-08-23 Dolores Bernenko, Sang Hoon Lee, Ludvig Lizana
Researchers have developed chromosome capture methods such as Hi-C to better understand DNA’s 3D folding in nuclei. The Hi-C method captures contact frequencies between DNA segment pairs across the genome. When analyzing Hi-C data sets, it is common to group these pairs using standard bioinformatics methods (e.g. PCA). Other approaches handle Hi-C data as weighted networks, where connected node pairs
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A reasoning of economic complexity based on simulated general equilibrium international trade model * J. Phys. Complex Pub Date : 2023-07-26 Yumin Hu, Zhongchen Fan, Justin Yifu Lin, Mingzhi (Jimmy) Xu
By simulating a multi-country general equilibrium international trade model, we investigate how the economic complexity index (ECI) and fitness index (FI) are related directly to economic fundamentals with a clear basis in theory. The model is based on Eaton and Kortum (2002 Econometrica 70 1741–79) and combines factor endowment (Heckscher-Ohlin) and technological (Ricardian) reasons for specialization
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Hierarchical team structure and multidimensional localization (or siloing) on networks J. Phys. Complex Pub Date : 2023-07-25 Laurent Hébert-Dufresne, Guillaume St-Onge, John Meluso, James Bagrow, Antoine Allard
Knowledge silos emerge when structural properties of organizational interaction networks limit the diffusion of information. These structural barriers are known to take many forms at different scales—hubs in otherwise sparse organizations, large dense teams, or global core-periphery structure—but we lack an understanding of how these different structures interact and shape dynamics. Here we take a
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Stasis in heterogeneous networks of coupled oscillators: discontinuous transition with hysteresis J. Phys. Complex Pub Date : 2023-07-13 Samir Sahoo, Awadhesh Prasad, Ramakrishna Ramaswamy
We consider a heterogeneous ensemble of dynamical systems in R4 that individually are either attracted to fixed points (and are termed inactive) or to limit cycles (in which case they are termed active). These distinct states are separated by bifurcations that are controlled by a single parameter. Upon coupling them globally, we find a discontinuous transition to global inactivity (or stasis) when
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A network approach to atomic spectra J. Phys. Complex Pub Date : 2023-07-06 David Wellnitz, Armin Kekić, Julian Heiss, Michael Gertz, Matthias Weidemüller, Andreas Spitz
Network science provides a universal framework for modeling complex systems, contrasting the reductionist approach generally adopted in physics. In a prototypical study, we utilize network models created from spectroscopic data of atoms to predict microscopic properties of the underlying physical system. For simple atoms such as helium, an a posteriori inspection of spectroscopic network communities
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A controlled transfer entropy approach to detect asymmetric interactions in heterogeneous systems J. Phys. Complex Pub Date : 2023-06-27 Rishita Das, Maurizio Porfiri
Transfer entropy is emerging as the statistical approach of choice to support the inference of causal interactions in complex systems from time-series of their individual units. With reference to a simple dyadic system composed of two coupled units, the successful application of net transfer entropy-based inference relies on unidirectional coupling between the units and their homogeneous dynamics.
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Boosted fluctuation responses in power grids with active voltage dynamics J. Phys. Complex Pub Date : 2023-06-16 Moritz Thümler, Marc Timme
Secure electric energy supply and thus stable operation of power grids fundamentally relies on their capability to cope with fluctuations. Here, we study how active voltage dynamics impacts the collective response dynamics of networked power grids. We find that the systems driven by ongoing fluctuating inputs exhibit a bulk, a resonance, and a localized grid frequency response regime, as for static
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Minor extensions of the logistic equation for growth curves of word counts on online media: parametric observation of diversity of growth in society J. Phys. Complex Pub Date : 2023-06-12 Hayafumi Watanabe
To understand the growth phenomena in collective human systems, we analyzed monthly word count time series of new vocabularies extracted from approximately 1 billion Japanese blog articles from 2007 to 2019. In particular, we first introduced the extended logistic equation by adding one parameter to the original equation and showed that the model can consistently reproduce various patterns of actual
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Similarity matrix average for aggregating multiplex networks J. Phys. Complex Pub Date : 2023-06-09 Federica Baccini, Lucio Barabesi, Eugenio Petrovich
We introduce a methodology based on averaging similarity matrices with the aim of integrating the layers of a multiplex network into a single monoplex network. Multiplex networks are adopted for modelling a wide variety of real-world frameworks, such as multi-type relations in social, economic and biological structures. More specifically, multiplex networks are used when relations of different nature
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Syndication network associates with specialisation and performance of venture capital firms J. Phys. Complex Pub Date : 2023-06-08 Qing Yao, Shaodong Ma, Jing Liang, Kim Christensen, Wanru Jing, Ruiqi Li
The Chinese venture capital (VC) market is a young and rapidly expanding financial subsector. Gaining a deeper understanding of the investment behaviours of VC firms is crucial for the development of a more sustainable and healthier market and economy. Contrasting evidence supports that either specialisation or diversification helps to achieve a better investment performance. However, the impact of
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Laplacian dynamics of convergent and divergent collective behaviors J. Phys. Complex Pub Date : 2023-05-26 Yang Tian, Yunhui Xu, Pei Sun
Collective dynamics is ubiquitous in various physical, biological, and social systems, where simple local interactions between individual units lead to complex global patterns. A common feature of diverse collective behaviors is that the units exhibit either convergent or divergent evolution in their behaviors, i.e. becoming increasingly similar or distinct, respectively. The associated dynamics changes
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Structure and stability of the Indian power transmission network J. Phys. Complex Pub Date : 2023-05-26 Vedang Tamhane, G Ambika
We present the study on the Indian power transmission network using the framework of a complex network and quantify its structural properties. For this, we build the network structure underlying the Indian power grid, using two of its most prevalent power lines. We construct an equivalent model of an exponential network and study its structural changes with changes in two parameters related to redundancy
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Spatial patterns and biodiversity in rock-paper-scissors models with regional unevenness J. Phys. Complex Pub Date : 2023-05-26 J Menezes, M Tenorio
Climate changes may affect ecosystems destabilising relationships among species. We investigate the spatial rock-paper-scissors models with a regional unevenness that reduces the selection capacity of organisms of one species. Our results show that the regionally weak species predominates in the local ecosystem, while spiral patterns appear far from the region, where individuals of every species play
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Permutation entropy of indexed ensembles: quantifying thermalization dynamics J. Phys. Complex Pub Date : 2023-05-25 Andrés Aragoneses, Arie Kapulkin, Arjendu K Pattanayak
We introduce ‘PI-Entropy’ Π(ρ˜) (the Permutation entropy of an Indexed ensemble) to quantify mixing due to complex dynamics for an ensemble ρ of different initial states evolving under identical dynamics. We find that Π(ρ˜) acts as an excellent proxy for the thermodynamic entropy S(ρ) but is much more computationally efficient. We study 1-D and 2D iterative maps and find that Π(ρ˜) dynamics distinguish
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Demographic noise in complex ecological communities J. Phys. Complex Pub Date : 2023-05-19 Ferran Larroya, Tobias Galla
We introduce an individual-based model of a complex ecological community with random interactions. The model contains a large number of species, each with a finite population of individuals, subject to discrete reproduction and death events. The interaction coefficients determining the rates of these events is chosen from an ensemble of random matrices, and is kept fixed in time. The set-up is such