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Analysis of labor productivity using large-scale data of firm's financial statements

EUROPEAN PHYSICAL JOURNAL B 2010年第4期76卷 491-499页

作者： Ikeda, Y. Souma, W. Aoyama, H. Fujiwara, Y. Iyetomi, H. Hitachi Ltd Hitachi Res Lab Hitachi Ibaraki 3191221 Japan Nihon Univ Coll Sci & Technol Chiba 2748501 Japan ATR Labs Kyoto 6190288 Japan Kyoto Univ Dept Phys Kyoto 6068501 Japan Niigata Univ Dept Phys Niigata 9502181 Japan

We investigated labor productivity distribution by analyzing large-scale financial statement data consisting of listed and unlisted Japanese firms to clarify the characteristics of the Japanese labor market. Both high and low productivity sides of the labor productivity distribution follows the power-law distribution. Large inequality in the low productivity side was observed only for the manufacturing sectors in Japan fiscal year (JFY) 1999 and observed for both the manufacturing and non-manufacturing sectors in JFY 2002. The decline in the Japanese GDP in JFY 1999 and JFY 2002 were coincided with the large inequality in the low productivity side of the distribution. A lower peak was found for all non-manufacturing sectors. This might be the origin of the low productivity of the non-manufacturing sectors reported in recent economic studies.

关键词： Dynamics of social systems structures and organization in complex systems

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Comparison of methods for the detection of node group membership in bipartite networks

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EUROPEAN PHYSICAL JOURNAL B 2009年第4期72卷 671-677页

作者： Sawardecker, E. N. Amundsen, C. A. Sales-Pardo, M. Amaral, L. A. N. Northwestern Univ Dept Chem & Biol Engn Evanston IL 60208 USA Univ Wisconsin Dept Chem & Biol Engn Madison WI 53706 USA Northwestern Univ NW Inst Complex Syst Evanston IL 60208 USA Northwestern Univ Clin & Translat Sci Inst Chicago IL 60611 USA Northwestern Univ HHMI Evanston IL 60208 USA

Most real-world networks considered in the literature have a modular structure. Analysis of these real-world networks often are performed under the assumption that there is only one type of node. However, social and biochemical systems are often bipartite networks, meaning that there are two exclusive sets of nodes, and that edges run exclusively between nodes belonging to different sets. Here we address the issue of module detection in bipartite networks by comparing the performance of two classes of group identification methods - modularity maximization and clique percolation - on an ensemble of modular random bipartite networks. We find that the modularity maximization methods are able to reliably detect the modular bipartite structure, and that, under some conditions, the simulated annealing method outperforms the spectral decomposition method. We also find that the clique percolation methods are not capable of reliably detecting the modular bipartite structure of the bipartite model networks considered.

关键词： structures and organization in complex systems

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Global firing induced by network disorder in ensembles of active rotators

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EUROPEAN PHYSICAL JOURNAL B 2008年第3期62卷 319-326页

作者： Tessone, C. J. Zanette, D. H. Toral, R. Swiss Fed Inst Technol Chair Syst Design CH-8032 Zurich Switzerland Ctr Atom Bariloche Consejo Nacl Invest Cient & Tecn RA-8400 San Carlos De Bariloche Rio Negro Argentina Inst Balseiro RA-8400 San Carlos De Bariloche Rio Negro Argentina CSIC UIB IFISC Palma de Mallorca 07122 Spain

We study the influence of repulsive interactions on an ensemble of coupled excitable rotators. We find that a moderate fraction of repulsive interactions can trigger global firing of the ensemble. The regime of global firing, however, is suppressed in sufficiently large systems if the network of repulsive interactions is fully random, due to self-averaging in its degree distribution. We thus introduce a model of partially random networks with a broad degree distribution, where self-averaging due to size growth is absent. In this case, the regime of global firing persists for large sizes. Our results extend previous work on the constructive effects of diversity in the collective dynamics of complex systems.

关键词： Synchronization, coupled oscillators Nonlinear dynamics and chaos structures and organization in complex systems

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Ordering phase transition in the one-dimensional Axelrod model

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EUROPEAN PHYSICAL JOURNAL B 2002年第3期30卷 399-406页

作者： Vilone, D Vespignani, A Castellano, C Univ Roma La Sapienza Dipartimento Fis I-00185 Rome Italy Abdus Salam Int Ctr Theoret Phys I-34100 Trieste Italy INFM Unita Roma 1 I-00185 Rome Italy

We study the one-dimensional behavior of a cellular automaton aimed at the description of the formation and evolution of cultural domains. The model exhibits a non-equilibrium transition between a phase with all the system sharing the same culture and a disordered phase of coexisting regions with different cultural features. Depending on the initial distribution of the disorder the transition occurs at different values of the model parameters. This phenomenology is qualitatively captured by a mean-field approach, which maps the dynamics into a multi-species reaction-diffusion problem.

关键词： Dynamics of social systems Lattice theory and statistics (Ising, Potts, etc.) structures and organization in complex systems

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Model of mobile agents for sexual interactions networks

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EUROPEAN PHYSICAL JOURNAL B 2006年第3期49卷 371-376页

作者： González, MC Lind, PG Herrmann, HJ Univ Stuttgart Inst Computat Phys D-70569 Stuttgart Germany Ctr Fis Teor & Computac P-1649003 Lisbon Portugal Univ Fed Ceara Dept Fis BR-60451970 Fortaleza Ceara Brazil

We present a novel model to simulate real social networks of complex interactions, based in a system of colliding particles (agents). The network is build by keeping track of the collisions and evolves in time with correlations which emerge due to the mobility of the agents. Therefore, statistical features are a consequence only of local collisions among its individual agents. Agent dynamics is realized by an event-driven algorithm of collisions where energy is gained as opposed to physical systems which have dissipation. The model reproduces empirical data from networks of sexual interactions, not previously obtained with other approaches.

关键词： Social and economic systems structures and organization in complex systems Networks and genealogical trees systems obeying scaling laws

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The network of concepts in written texts

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EUROPEAN PHYSICAL JOURNAL B 2006年第4期49卷 523-529页

作者： Caldeira, S. M. G. Lobao, T. C. Petit Andrade, R. F. S. Neme, A. Miranda, J. G. V. Univ Fed Bahia Inst Fis BR-40210340 Salvador BA Brazil Univ Fed Bahia Inst Matemat BR-40210340 Salvador BA Brazil Univ Marne la Vallee Inst Gaspard Monge F-77454 Marne La Vallee 2 France

complex network theory is used to investigate the structure of meaningful concepts in written texts of individual authors. Networks have been constructed after a two phase filtering, where words with less meaning contents are eliminated and all remaining words are set to their canonical form, without any number, gender or time flexion. Each sentence in the text is added to the network as a clique. A large number of written texts have been scrutinised, and it is found that texts have small-world as well as scale-free structures. The growth process of these networks has also been investigated, and a universal evolution of network quantifiers have been found among the set of texts written by distinct authors. Further analyses, based on shuffling procedures taken either on the texts or on the constructed networks, provide hints on the role played by the word frequency and sentence length distributions to the network structure.

关键词： structures and organization in complex systems Networks and genealogical trees Combinatorics, graph theory

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Sudden onset of log-periodicity and superdiffusion in non-Markovian random walks with amnestically induced persistence: exact results

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EUROPEAN PHYSICAL JOURNAL B 2009年第3期72卷 427-433页

作者： Felisberto, M. L. Passos, F. S. Ferreira, A. S. da Silva, M. A. A. Cressoni, J. C. Viswanathan, G. M. Univ Fed Alagoas Inst Fis BR-57072970 Maceio AL Brazil Univ Sao Paulo Dept Quim & Fis FCFRP BR-14040903 Ribeirao Preto SP Brazil Univ New Mexico Consortium Amer Interdisciplinary Sci Albuquerque NM 87131 USA Univ New Mexico Dept Phys & Astron Albuquerque NM 87131 USA

Random walks can undergo transitions from normal diffusion to anomalous diffusion as some relevant parameter varies, for instance the L,vy index in L,vy flights. Here we derive the Fokker-Planck equation for a two-parameter family of non-Markovian random walks with amnestically induced persistence. We investigate two distinct transitions: one order parameter quantifies log-periodicity and discrete scale invariance in the first moment of the propagator, whereas the second order parameter, known as the Hurst exponent, describes the growth of the second moment. We report numerical and analytical results for six critical exponents, which together completely characterize the properties of the transitions. We find that the critical exponents related to the diffusion-superdiffusion transition are identical in the positive feedback and negative feedback branches of the critical line, even though the former leads to classical superdiffusion whereas the latter gives rise to log-periodic superdiffusion.

关键词： structures and organization in complex systems Random walks and Lévy flights Neuroscience

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Clusters in weighted macroeconomic networks: the EU case. Introducing the overlapping index of GDP/capita fluctuation correlations

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EUROPEAN PHYSICAL JOURNAL B 2008年第4期63卷 533-539页

作者： Gligor, M. Ausloos, M. Natl Coll Roman Voda Neamt 5550 Romania Univ Liege GRAPES B-4000 Liege Belgium

GDP/capita correlations are investigated in various time windows (TW), for the time interval 1990-2005. The target group of countries is the set of 25 EU members, 15 till 2004 plus the 10 countries which joined EU later on. The TW-means of the statistical correlation coefficients are taken as the weights (links) of a fully connected network having the countries as nodes. Thereafter we de. ne and introduce the overlapping index of weighted network nodes. A cluster structure of EU countries is derived from the statistically relevant eigenvalues and eigenvectors of the adjacency matrix. This may be considered to yield some information about the structure, stability and evolution of the EU country clusters in a macroeconomic sense.

关键词： structures and organization in complex systems Networks and genealogical trees Economics, econophysics, financial markets, business and management Dynamics of social systems

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Relating the microscopic rules in coalescence-fragmentation models to the cluster-size distribution

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EUROPEAN PHYSICAL JOURNAL B 2009年第2期72卷 289-302页

作者： Ruszczycki, B. Burnett, B. Zhao, Z. Johnson, N. F. Univ Miami Dept Phys Coral Gables FL 33146 USA Univ Oxford Rudolf Peierls Ctr Theoret Phys Oxford England

Coalescence-fragmentation problems are now of great interest across the physical, biological, and social sciences. They are typically studied from the perspective of rate equations, at the heart of which are the rules used for coalescence and fragmentation. Here we discuss how changes in these microscopic rules affect the macroscopic cluster-size distribution which emerges from the solution to the rate equation. Our analysis elucidates the crucial role that the fragmentation rule can play in such dynamical grouping models. We focus our discussion on two well-known models whose fragmentation rules lie at opposite extremes. In particular, we provide a range of generalizations and new analytic results for the well-known model of social group formation developed by Eguiluz and Zimmermann, [Phys. Rev. Lett. 85, 5659 (2000)]. We develop analytic perturbation treatments of this original model, and extend the analytic analysis to the treatment of growing and declining populations.

关键词： structures and organization in complex systems Networks and genealogical trees Economics, econophysics, financial markets, business and management General theory and mathematical aspects

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Synchronization in evolving snowdrift game model

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EUROPEAN PHYSICAL JOURNAL B 2009年第3期69卷 431-438页

作者： Huang, Y. Wu, L. Zhu, S. Q. Suzhou Univ Sch Phys Sci & Technol Suzhou 215006 Jiangsu Peoples R China

The interaction between the evolution of the game and the underlying network structure with evolving snowdrift game model is investigated. The constructed network follows a power-law degree distribution typically showing scale-free feature. The topological features of average path length, clustering coefficient, degree-degree correlations and the dynamical feature of synchronizability are studied. The synchronizability of the constructed networks changes by the interaction. It will converge to a certain value when sufficient new nodes are added. It is found that initial payoffs of nodes greatly affect the synchronizability. When initial payoffs for players are equal, low common initial payoffs may lead to more heterogeneity of the network and good synchronizability. When initial payoffs follow certain distributions, better synchronizability is obtained compared to equal initial payoff. The result is also true for phase synchronization of nonidentical oscillators.

关键词： systems obeying scaling laws structures and organization in complex systems World Wide Web, Internet

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