担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevResearch.7.013235

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-024-63719-z

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

The trade distance is an important constraining factor underpinning the emergence of social and economic interactions of complex systems. However, agent-based studies supported by the granular analysis of distances are limited. Here, we present a complexity method that places the actual geographical locations of individual firms in Japan at the epicentre of our research. By combining methods derived from network science together with information theory measures, and by using a comprehensive dataset of Japanese inter-firm business transactions, we evaluate the effects of spatial features on the structural patterns of the economy. We find that the normalised probability distributions of the distances between interacting firms obey a power law like decay concomitant with the sizes of firms and regions. Furthermore, small firms would reach large distances to become customers of large firms, while trading between either only small firms or only large firms tends to be at smaller distances. Furthermore, a time evolution analysis suggests a reduction in the overall average trading distances in last 20 years. Lastly, our analysis concerning the trading dynamics among prefectures indicates that the preference to trade with neighbouring prefectures tends to be more pronounced at rural regions as opposed to the larger central conurbations.

DOI： 10.3390/math12081244

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<jats:title>Abstract</jats:title><jats:p>We develop a single two-layered model framework that captures and replicates both the statistical properties of the network as well as those of the intrinsic quantities of the agents. Our model framework consists of two distinct yet connected elements that were previously only studied in isolation, namely methods related to temporal network structures and those associated with money transport flows. Within this context, the network structure emerges from the first layer and its topological structure is transferred to the second layer associated with the money transactions. In this manner, we can explain how the micro-level dynamics of the agents within the network lead to the exogenous manifestation of the aggregated system statistical data en-wrapping the very same agents within the system. This is done by capturing the essential dynamics of collective motion in complex networks that enable the simultaneous emergence of tent-shaped distributions in growth rates within the agents, together with the emergence of scaling properties within the network in the study. We can validate the model framework and dynamics by applying these to the context of the real-world inter-firm trading network of firms in Japan and comparing the results of the statistical distributions at both network and agent levels in a temporal manner. In particular, we compare our results to the fundamental quantities supporting the seven empirical laws observed in data: the degree distribution, the mean degree growth rate over time, the age distribution of the firms, the preferential attachment, the sales distribution in steady states, their growth rates, their scaling relations generated by the model. We find these results to be nearly identical to the real-world data. The framework has the potential to be transformed into a forecasting tool to support decision-makers on financial and prudential policies.</jats:p>

DOI： 10.1038/s41598-024-54719-0

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その他リンク： https://www.nature.com/articles/s41598-024-54719-0

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society (APS)  

<jats:p>Nonlinear transport has been observed in many real systems, such as international trade, business transactions, human movement, and urban traffic. To understand the fundamental properties of transport in such systems, several models have been proposed in the past few years. These models exhibit complex behavior due to the interplay between nonlinearity and the underlying network topology. We studied a transport equation on three-body network motifs both numerically and analytically, and we found bifurcation on two motifs and hysteresis of a model on one motif. These three motifs show different bifurcation points. The first two motifs have a branching node, i.e., a node with outdegree 2, and the third motif is a fully connected bidirectional triangle. In particular, the hysteresis on the bidirectional triangle is not predictable from the linear stability analysis on the uniform stationary solution. The analysis based on the self-consistency equation of the parameter <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>u</a:mi></a:math> [see Eq. (6) for the precise definition] measuring the ratio between sizes on two nodes reveals the following: The bifurcation on the first two motifs is due to supercritical pitchfork bifurcation. The difference between these two motifs comes from the existence of bidirectional edges. The hysteresis on the third motif is due to the combination of the saddle-node and transcritical bifurcation. Our results imply that the nonlinear transport model exhibits nontrivial behavior even in minimal settings and that the bifurcation on large-scale networks becomes far more complex and unpredictable from the underlying network structure.</jats:p>
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<jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement>
<jats:copyright-year>2024</jats:copyright-year>
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DOI： 10.1103/physrevresearch.6.013059

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その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevResearch.6.013059/fulltext

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<jats:title>Abstract</jats:title><jats:p>We analyze the time series of hashtag numbers of social media data. We observe that the usage distribution of hashtags is characterized by a fat-tailed distribution with a size-dependent power law exponent and we find that there is a clear dependency between the growth rate distributions of hashtags and size of hashtags usage. We propose a generalized random multiplicative process model with a theory that explains the size dependency of the fat-tailed distribution. Numerical simulations show that our model reproduces these size-dependent properties nicely. We expect that our model is useful for understanding the mechanism of fat-tailed distributions in various fields of science and technology.</jats:p>

DOI： 10.1038/s41598-023-49572-6

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<jats:title>Abstract</jats:title><jats:p>The convenience store industry in Japan holds immense significance, making a thorough comprehension of customer purchase behaviour invaluable for companies aiming to gain insights into their customer base. In this paper, we propose a novel application of a Markov network model to simulate purchases guided by stopping probabilities calculated from real data. Each node in the Markov network represents different product categories available for purchase. Additionally, we introduce the concept of a “driving force,” quantifying the influence of purchasing product A on the likelihood of purchasing product B, compared to random purchasing. For instance, our analysis reveals that the inclusion of nutrient bars in a purchase set leads to, on average, a 13% reduction in tobacco purchases compared to random patterns. To validate our approach, we compare the simulated macro-level purchase behaviours with real point of Sale (POS) data obtained from a prominent convenience store giant, 7-Eleven. The dataset is comprised of roughly 54 million receipts, in which we focus on the product categories existing in this dataset rather than individual products. Our model successfully replicates the purchase size distribution for 99.9% of all purchases and the purchase counts across various product categories, demonstrating its efficacy in capturing broad purchase patterns.</jats:p>

DOI： 10.1038/s41598-024-60752-w

DOI： 10.21203/rs.3.rs-3229845/v1

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

High-resolution fecal pharmacokinetics are crucial for optimizing therapeutic design and evaluating gastrointestinal motility. However, empirical studies with detailed fecal concentration over time data remain limited. This study aims to characterize fecal pharmacokinetics through high-frequency sampling and parallelized fecal concentration quantification, establishing a simple pharmacokinetics model with physiologically interpretable parameters. We quantified vancomycin concentrations in fecal samples collected at a minimum interval of 4 hours from C57BL/6N mice following a single oral administration of either a low (1 mg/mL) or high (20 mg/mL) dose. Fecal concentrations gradually increased and exhibited an exponential decay, leading to the development of a compartmental model with an absorption phase. This simple model accurately fit the experimental data and provided physiological explanations for intra- and inter-individual pharmacokinetics variability. The results suggest that inter-individual differences in pharmacokinetics are attributable to fecal elimination capacity, which may be influenced by drug dosage via changes in gastrointestinal motility. Since the model predicts antibiotic concentrations within the gastrointestinal tract, it can be applied to fundamental studies investigating the effects of antibiotics on the gut microbiome and gastrointestinal motility.

DOI： 10.1101/2023.05.05.539495

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

We introduce a new non-black-box method of extracting multiple areas in a high-dimensional big data space where data points that satisfy specific conditions are highly concentrated. First, we extract one-dimensional areas where the data that satisfy specific conditions are mostly gathered by using the Bayesian method. Second, we construct higher-dimensional areas where the densities of focused data points are higher than the simple combination of the results for one dimension, and then we verify the results through data validation. Third, we apply this method to estimate the set of significant factors shared in successful firms with growth rates in sales at the top 1% level using 156-dimensional data of corporate financial reports for 12 years containing about 320,000 firms. We also categorize high-growth firms into 15 groups of different sets of factors.

DOI： 10.3390/e25030488

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society (APS)  

We propose a data-driven stochastic method that allows the simulation of a complex system's long-term evolution. Given a large amount of historical data on trajectories in a multi-dimensional phase space, our method simulates the time evolution of a system based on a random selection of partial trajectories in the data without detailed knowledge of the system dynamics. We apply this method to a large data set of time evolution of approximately one million business firms for a quarter century. Accordingly, from simulations starting from arbitrary initial conditions, we obtain a stationary distribution in three-dimensional log-size phase space, which satisfies the allometric scaling laws of three variables. Furthermore, universal distributions of fluctuation around the scaling relations are consistent with the empirical data.

DOI： 10.1103/physreve.106.064304

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その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevE.106.064304/fulltext

担当区分：最終著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

The two-body stochastic dealer model is revisited to provide an exact solution to the average order-book profile using the kinetic approach. The dealer model is a microscopic financial model where individual traders make decisions on limit-order prices stochastically and then reach agreements on transactions. In the literature, this model was solved for several cases: an exact solution for two-body traders$$N=2$$and a mean-field solution for many traders$$N\gg 1$$. Remarkably, while kinetic theory plays a significant role in the mean-field analysis for$$N\gg 1$$, its role is still elusive for the case of$$N=2$$. In this paper, we revisit the two-body dealer model$$N=2$$to clarify the utility of the kinetic theory. We first derive the exact master-Liouville equations for the two-body dealer model. We next illustrate the physical picture of the master-Liouville equation from the viewpoint of the probability currents. The master-Liouville equations are then solved exactly to derive the order-book profile and the average transaction interval. Furthermore, we introduce a generalised two-body dealer model by incorporating interaction between traders via the market midprice and exactly solve the model within the kinetic framework. We finally confirm our exact solution by numerical simulations. This work provides a systematic mathematical basis for the econophysics model by developing better mathematical intuition.

DOI： 10.1007/s10955-022-03022-1

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その他リンク： https://link.springer.com/article/10.1007/s10955-022-03022-1/fulltext.html

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

<jats:title>Abstract</jats:title><jats:p>During the COVID-19 pandemic, governments faced difficulties in implementing mobility restriction measures, as no clear quantitative relationship between human mobility and infection spread in large cities is known. We developed a model that enables quantitative estimations of the infection risk for individual places and activities by using smartphone GPS data for the Tokyo metropolitan area. The effective reproduction number is directly calculated from the number of infectious social contacts defined by the square of the population density at each location. The difference in the infection rate of daily activities is considered, where the ‘stay-out’ activity, staying at someplace neither home nor workplace, is more than 28 times larger than other activities. Also, the contribution to the infection strongly depends on location. We imply that the effective reproduction number is sufficiently suppressed if the highest-risk locations or activities are restricted. We also discuss the effects of the Delta variant and vaccination.</jats:p>

DOI： 10.1038/s41598-022-22420-9

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その他リンク： https://www.nature.com/articles/s41598-022-22420-9

担当区分：最終著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 日本物理学会  

ウェブサービスの一つであるSNSが国内外問わず広く普及している．SNSの代表例であるFacebookは，世界中で登録者数が28億人ともいわれている．SNSの中では，実社会と同様に地震情報などのニュース速報が瞬時に広まったり，誹謗中傷による告発があったりと，様々な現象が起きている．特に近年，SNSで問題視されているのが，多くの人に誤情報があたかも正情報として伝わり，社会的な混乱を引き起こす現象，デマの拡散である．

SNSにおける情報伝播は，とらえどころがなく，研究対象として，ましてや物理の問題として扱うことができるのか議論が分かれるところであろう．実際に，SNSを構成する人間には個性があり，その間にやり取りされる情報も多種多様な文脈があり，統一的に扱うことは到底困難にも感じる．さらにSNSを運営するのは，特定の営利企業であり，その性質は自然現象とは大きく異なる．

しかし，一歩引いて観察すると，SNSは構成している人をノード，その間を流れている情報をリンクとするネットワークとして表現することができる．しかも，そのやりとりは電子的に精緻に記録されているため，大規模に分析することができる．そのため，SNSに関する研究は特にコンピュータサイエンスや情報処理の分野において活発に行われている．

一方で，情報が伝播していくネットワーク構造のみに着目した研究は，実はあまり多くはない．そこで，われわれは現象をなるべく単純化した形で，正誤情報が伝播していくネットワーク構造の違いを比較した．

具体的には，日本でも広く使われているSNSの一つであるTwitterにおいて，アカウントをノード，その間をつなぐリツイートとよばれる情報の転送関係をリンクとしたネットワークを正情報と誤情報の両方で構築し比較した．そして，これらを比較した結果，誤情報の方が複雑なネットワーク構造をしている点に着目した．特に，正情報の場合，発信源を中心とした星型で伝播するのに対し，誤情報の場合，発信源は必ずしもネットワークの中心とはなっていない．誤情報では，目にした情報を，発信源まで遡ることなく，そのまま身近な人へと転送することがしばしば起こっていることを表している．

このような伝播ネットワークの違いを数値化することにより，伝播している情報の文脈や，情報を発信・転送する人の属性などを考慮することなく，SNSで広まっている情報が正誤どちらに近いのかを評価できるようになる．さらに，数値化においては，ネットワークのローカルな情報である，リンク数の平均，および二乗平均だけを用いている点は，重要である．例えばノードの重要度を表す代表的な指標である媒介中心性を計算するには，ネットワーク中のすべてのノードペア間の最短経路を計算する必要がある．一方，リンク数の平均，および二乗平均であれば，注目するノードのローカルな情報のみで計算ができる．

今後もSNSによる情報流通が増えていくと考えられる．透明性が高く，計算量も軽い指標で新たな「情報生態系」を捉え，明らかにし，さらに社会へも還元するような取り組みは，重要性を増していくのではないだろうか．

DOI： 10.11316/butsuri.77.7_458

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-022-13789-8

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その他リンク： https://www.nature.com/articles/s41598-022-13789-8

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-022-13789-8

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Bursts and collective emotion have been widely studied in social physics field where researchers use mathematical models to understand human social dynamics. However, few researches recognize and separately analyze the internal and external influence on burst behaviors. To bridge this gap, we introduce a non-parametric approach to classify an interevent time series into five scenarios: random arrival, endogenous burst, endogenous non-burst, exogenous burst and exogenous non-burst. In order to process large-scale social media data, we first segment the interevent time series into sections by detecting change points. Then we use the rule-based algorithm to classify the time series based on its distribution. To validate our model, we analyze 27.2 million COVID-19 related comments collected from Chinese social media between January to October 2020. We adopt the emotion category called Profile of Mood States which consists of six emotions:Anger,Depression,Fatigue,Vigor,TensionandConfusion. This enables us to compare the burst features of different collective emotions during the COVID-19 period. The burst detection and classification approach introduced in this paper can also be applied to analyzing other complex systems, including but not limited to social media, financial market and signal processing.

DOI： 10.1038/s41598-022-07067-w

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その他リンク： https://www.nature.com/articles/s41598-022-07067-w

掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.physrep.2021.10.005

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Focusing on the diffusion-localization transition, we theoretically analyzed a nonlinear gravity-type transport model defined on networks called regular ring lattices, which have an intermediate structure between the complete graph and the simple ring. Exact eigenvalues were derived around steady states, and the values of the transition points were evaluated for the control parameter characterizing the nonlinearity. We also analyzed the case of the Bethe lattice (or Cayley tree) and found that the transition point is 1/2, which is the lowest value ever reported.

DOI： 10.1007/s10955-022-02882-x

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その他リンク： https://link.springer.com/article/10.1007/s10955-022-02882-x/fulltext.html

担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

Traders who instantly react to changes in the financial market and place orders in milliseconds are called high-frequency traders (HFTs). HFTs have recently become more prevalent and attracting attention in the study of market microstructures. In this study, we used data to track the order history of individual HFTs in the USD/JPY forex market to reveal how individual HFTs interact with the order book and what strategies they use to place their limit orders. Specifically, we introduced an 8-dimensional multivariate Hawkes process that included the excitations due to the occurrence of limit orders, cancel orders, and executions in the order book change, and performed maximum likelihood estimations of the limit order processes for 134 HFTs. As a result, we found that the limit order generation processes of 104 of the 134 HFTs were modeled by a multivariate Hawkes process. In this analysis of the EBS market, the HFTs whose strategies were modeled by the Hawkes process were categorized into three groups according to their excitation mechanisms: (1) those excited by executions; (2) those that were excited by the occurrences or cancellations of limit orders; and (3) those that were excited by their own orders.

DOI： 10.3390/e24020214

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

To prevent the spread of the COVID-19 pandemic, governments in various countries have severely restricted the movement of people. The large amount of detailed human location data obtained from mobile phone users is useful for understanding the change of flow patterns of people under the effect of pandemic. In this paper, we observe the synchronized human flow during the COVID-19 pandemic using Global Positioning System data of about 1 million people obtained from mobile phone users. We apply the drainage basin analysis method which we introduced earlier for characterization of macroscopic human flow patterns to observe the effect of the spreading pandemic. Before the pandemic the afternoon basin size distribution has been approximated by an exponential distribution, however, the distribution of Tokyo and Sapporo, which were most affected by the first wave of COVID-19, deviated significantly from the exponential distribution. On the other hand, during the morning rush hour, the scaling law holds universally, i.e., in all cities, even though the number of moving people in the basin has decreased significantly. The fact that these scaling laws, which are closely related to the three-dimensionality structure of the city and the fractal structure of the transportation network, have not changed indicates that the macroscopic human flow features are determined mainly by the means of transport and the basic structure of cities which are invariant of the pandemic.

DOI： 10.1007/s41109-021-00416-0

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その他リンク： https://link.springer.com/article/10.1007/s41109-021-00416-0/fulltext.html

担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

The Sigma-Pi structure investigated in this work consists of the sum of products of an increasing number of identically distributed random variables. It appears in stochastic processes with random coefficients and also in models of growth of entities such as business firms and cities. We study the Sigma-Pi structure with Bernoulli random variables and find that its probability distribution is always bounded from below by a power-law function regardless of whether the random variables are mutually independent or duplicated. In particular, we investigate the case in which the asymptotic probability distribution has always upper and lower power-law bounds with the same tail-index, which depends on the parameters of the distribution of the random variables. We illustrate the Sigma-Pi structure in the context of a simple growth model with successively born entities growing according to a stochastic proportional growth law, taking both Bernoulli, confirming the theoretical results, and half-normal random variables, for which the numerical results can be rationalized using insights from the Bernoulli case. We analyze the interdependence among entities represented by the product terms within the Sigma-Pi structure, the possible presence of memory in growth factors, and the contribution of each product term to the whole Sigma-Pi structure. We highlight the influence of the degree of interdependence among entities in the number of terms that effectively contribute to the total sum of sizes, reaching the limiting case of a single term dominating extreme values of the Sigma-Pi structure when all entities grow independently.

DOI： 10.3390/e23020241

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/e23020168

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Detail observation of human locations became available recently by the development of information technology such as mobile phones with GPS (Global Positioning System). We analyzed temporal changes of global human flow patterns in urban regions based on mobile phones’ GPS data in 9 large cities in Japan. By applying a new concept of drainage basins in analogous to river flow patterns, we discovered several universal scaling relations. These include, the number of moving people in a drainage basin of diameter L is proportional to $$L^3$$ in the morning rush hour, which is surprisingly different from reasonable intuition of proportionality to the 2 dimensional area, $$L^2$$. We show that this unexpected 3 dimensional feature is related to the strong attraction of the city center to become a 3 dimensional structure due skyscrapers.

DOI： 10.1038/s41598-020-77163-2

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その他リンク： https://www.nature.com/articles/s41598-020-77163-2

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Public Library of Science (PLoS)  

We propose the epsilon-tau procedure to determine up- and down-trends in a time series, working as a tool for its segmentation. The method denomination reflects the use of a tolerance level ε for the series values and a patience level τ in the time axis to delimit the trends. We first illustrate the procedure in discrete random walks, deriving the exact probability distributions of trend lengths and trend amplitudes, and then apply it to segment and analyze the trends of U.S. dollar (USD)/Japanese yen (JPY) market time series from 2015 to 2018. Besides studying the statistics of trend lengths and amplitudes, we investigate the internal structure of the trends by grouping trends with similar shapes and selecting clusters of shapes that rarely occur in the randomized data. Particularly, we identify a set of down-trends presenting similar sharp appreciation of the yen that are associated with exceptional events such as the Brexit Referendum in 2016.

DOI： 10.1371/journal.pone.0239494

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Public Library of Science (PLoS)  

Foreign exchange rates movements exhibit significant cross-correlations even on very short time-scales. The effect of these statistical relationships become evident during extreme market events, such as flash crashes.In this scenario, an abrupt price swing occurring on a given market is immediately followed by anomalous movements in several related foreign exchange rates. Although a deep understanding of cross-currency correlations would be clearly beneficial for conceiving more stable and safer foreign exchange markets, the microscopic origins of these interdependencies have not been extensively investigated. We introduce an agent-based model which describes the emergence of cross-currency correlations from the interactions between market makers and an arbitrager. Our model qualitatively replicates the time-scale vs. cross-correlation diagrams observed in real trading data, suggesting that triangular arbitrage plays a primary role in the entanglement of the dynamics of different foreign exchange rates. Furthermore, the model shows how the features of the cross-correlation function between two foreign exchange rates, such as its sign and value, emerge from the interplay between triangular arbitrage and trend-following strategies.
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DOI： 10.1371/journal.pone.0234709

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

Social media can be a double-edged sword for society, either as a convenient channel exchanging ideas or as an unexpected conduit circulating fake news through a large population. While existing studies of fake news focus on theoretical modeling of propagation or identification methods based on machine learning, it is important to understand the realistic propagation mechanisms between theoretical models and black-box methods. Here we track large databases of fake news and real news in both, Weibo in China and Twitter in Japan from different cultures, which include their traces of re-postings. We find in both online social networks that fake news spreads distinctively from real news even at early stages of propagation, e.g. five hours after the first re-postings. Our finding demonstrates collective structural signals that help to understand the different propagation evolution of fake news and real news. Different from earlier studies, identifying the topological properties of the information propagation at early stages may offer novel features for early detection of fake news in social media.

DOI： 10.1140/epjds/s13688-020-00224-z

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その他リンク： http://link.springer.com/article/10.1140/epjds/s13688-020-00224-z/fulltext.html

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

<jats:p>From the viewpoint of statistical physics, ecosystems in the real world are very attractive targets of research as examples of far-from thermal equilibrium systems where various kinds of components are coming in and out continuously while keeping the whole systems quasi-stationary. As a fortunate example of a fully-observable ecosystem, we analyzed the comprehensive data of convenience stores where approximately 5% of the commodity species is replaced by new ones daily. The share of stores for each species fluctuates significantly; however, the entire distribution of shares is fairly stationary and follows the log-uniform distribution, that is, the power law distribution with exponent 0. We introduce an empirical time evolution model of shares and firstly deduce that the key mechanism of realizing this stationary distribution is random multiplicative diffusion in finite size spaces. Our model based on the general stochastic process is expected to be applicable to various dynamic systems, especially complex systems with highly nonlinear interactions.</jats:p>

DOI： 10.3390/e22030267

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：{MDPI} {AG}  

<jats:p>Complexity and information theory are two very valuable but distinct fields of research, yet sharing the same roots. Here, we develop a complexity framework inspired by the allometric scaling laws of living biological systems in order to evaluate the structural features of networks. This is done by aligning the fundamental building blocks of information theory (entropy and mutual information) with the core concepts in network science such as the preferential attachment and degree correlations. In doing so, we are able to articulate the meaning and significance of mutual information as a comparative analysis tool for network activity. When adapting and applying the framework to the specific context of the business ecosystem of Japanese firms, we are able to highlight the key structural differences and efficiency levels of the economic activities within each prefecture in Japan. Moreover, we propose a method to quantify the distance of an economic system to its efficient free market configuration by distinguishing and quantifying two particular types of mutual information, total and structural.</jats:p>

DOI： 10.3390/e22020206

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Public Library of Science (PLoS)  

DOI： 10.1371/journal.pone.0225853

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Public Library of Science (PLoS)  

Financial prices fluctuate as a results of the market impact of the flow of transactions between traders. Reciprocally, several studies of market microstructure have shown how decisions of individual traders or banks, implemented in their trading strategies, are affected by historical market information. However, little is known about the detailed processes of how such trading strategies at the micro level recursively affect future market information at the macro level. Using a special fined-grained dataset that allows us to track the complete trading behavior of specific banks in a U.S. dollar (USD) versus Japanese yen (JPY) market, we find that position management methods, defined as the number of units of USD bought or sold by banks against JPY, can be classified into two strategies: (1) banks increase their positions by trading in the same direction repeatedly, or (2) banks attempt to reduce their inventories by rapidly shifting their positions toward zero. We then demonstrate that their systematic position management strategies strongly influence future market prices, as demonstrated by our ability using this information to predict market prices about fifteen minutes in advance. Further, by detecting outlier trades, we reveal that traders seem to switch their strategies when they become aware of outlier trades. The evidence obtained here suggests that positions, which are a consequence of historical trading decisions based on the position management strategies of each bank, strongly influence future market prices, and we unravel how market prices at the macro level evolve through an interactive process involving the interaction between well-defined trading strategies at the micro level.
PLoS ONE, 14 (8)
ISSN:1932-6203

DOI： 10.1371/journal.pone.0220645

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Abstract

The analysis of interfirm business transaction networks provides invaluable insight into the trading dynamics and economic structure of countries. However, there is a general scarcity of data available recording real, accurate and extensive information for these types of networks. As a result, and in common with other types of network studies - such as protein interactions for instance - research tends to rely on partial and incomplete datasets, i.e. subsets, with less certain conclusions. Here, we make use of unstructured financial and corporate reporting data in Japan as the base source to construct a financial reporting network, which is then compared and contrasted to the wider real business transaction network. The comparative analysis between these two rich datasets - the proxy, partially derived network and the real, complete network at macro as well as local structural levels - provides an enhanced understanding of the non trivial relationships between partial sampled subsets and fully formed networks. Furthermore, we present an elemental agent based pruning algorithm that reconciles and preserves key structural differences between these two networks, which may serve as an embryonic generic framework of potentially wider use to network research, enabling enhanced extrapolation of conclusions from partial data or subsets.

DOI： 10.1038/s41598-019-47490-0

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その他リンク： https://www.nature.com/articles/s41598-019-47490-0

担当区分：最終著者,　責任著者   記述言語：英語   出版者・発行元：MDPI AG  

<jats:p>Waste reduction in retail is a fundamental problem for sustainability. Among waste reduction approaches such as recycling and donation, stock management based on demand estimation which leads to mitigate waste generation and maintain a high profit is expected to play an important role. However, demand estimation is generally difficult because fluctuations in sales are quite volatile, and stock-out leads to incomplete demand observation. Here, we propose data science solutions to estimate non-stationary demand with censored sales data including stock-outs and realize scientific stock management. Concretely, we extend a non-stationary time series analysis method based on Particle Filter to handle censored data, and combine it with the newsvendor problem formula to determine the optimal stock. Moreover, we provide a way of pricing waste reduction costs. A method to verify consistency between the statistical model and sales data is also proposed. Numerical analysis using actual Point-Of-Sales data in convenience stores shows food waste could be reduced several tenths percent keeping high profits in most cases. Specifically, in cases of foods disposed of frequently about 75% of working days, food waste decreases to about a quarter with the profit increases by about 140%. The way of pricing waste reduction costs tells new insights such as 27% waste reduction is achieved by 1% profit loss. Our method provides a practical solution for food waste reduction in the retail sector.</jats:p>

DOI： 10.3390/su11133589

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Public Library of Science (PLoS)  

DOI： 10.1371/journal.pone.0213843

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

Although scaling relations of power law forms have been revealed in a wide variety of complex systems, the origin of scaling relations in real systems remains mostly unsolved. Based on a long tradition in physics, we here explore the phase space dynamics of business companies, whose different measures of size have been found to exhibit multiple scaling relations. Using a large scale dataset of Japanese companies covering over two million companies for over two decades (1994–2015), we compile the data of three measures of size, namely, annual sales, number of employee and number of trading partners. Tracking the historical time evolution of companies, we first show that there exists a stable region that attracts most of the data points in the long time scale, although the company dynamics in the three-dimensional phase space looks random in a shorter time scale. We then elaborate on ‘evolving flow diagrams’ of the averaged motion in the 3D space. Remarkably, the flow diagrams indicate that a 3D curve which represents the scaling relations between the three size measures can be regarded as an approximate attractor of the averaged flows. The results could serve for better modeling and understanding of companies dynamics and our method can be applied to other dynamics such as social and biological phenomena.

DOI： 10.1088/1367-2630/ab0e55

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その他リンク： http://iopscience.iop.org/article/10.1088/1367-2630/ab0e55/pdf

担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s42001-019-00032-0

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その他リンク： http://link.springer.com/content/pdf/10.1007/s42001-019-00032-0.pdf

担当区分：最終著者,　責任著者   出版者・発行元：MDPI AG  

<jats:p>We propose a parameter estimation method for non-stationary Poisson time series with the abnormal fluctuation scaling, known as Taylor’s law. By introducing the effect of Taylor’s fluctuation scaling into the State Space Model with the Particle Filter, the underlying Poisson parameter’s time evolution is estimated correctly from given non-stationary time series data with abnormally large fluctuations. We also developed a discontinuity detection method which enables tracking the Poisson parameter even for time series including sudden discontinuous jumps. As an example of application of this new general method, we analyzed Point-of-Sales data in convenience stores to estimate change of probability of purchase of commodities under fluctuating number of potential customers. The effectiveness of our method for Poisson time series with non-stationarity, large discontinuities and Taylor’s fluctuation scaling is verified by artificial and actual time series.</jats:p>

DOI： 10.3390/stats2010005

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：IOP Publishing  

DOI： 10.1088/1742-5468/aaf109

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その他リンク： http://stacks.iop.org/1742-5468/2019/i=1/a=013403?key=crossref.49f3ee3044629730a35d9e3dc3b7a096

担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10015-018-0508-0

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その他リンク： http://link.springer.com/article/10.1007/s10015-018-0508-0/fulltext.html

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Public Library of Science (PLoS)  

There is a growing interest to understand financial markets as ecological systems, where the variety of trading strategies correspond to that of biological species. For this purpose, transaction data for individual traders are studied recently as empirical analyses. However, there are few empirical studies addressing how traders submit limit and market order at the level of individual traders. Since limit and market orders are key ingredients finally leading to transactions, it would be necessary to understand what kind of strategies are actually employed among traders before making transactions. Here we demonstrate the variety of limit-order and market-order strategies and show their roles in the financial markets from an ecological perspective. We find these trading strategies can be well-characterized by their response pattern to historical price changes. By applying a clustering analysis, we provide an overall picture of trading strategies as an ecological matrix, illustrating that liquidity consumers are likely to exhibit high trading performances compared with liquidity providers. Furthermore, we reveal both high-frequency traders (HFTs) and low-frequency traders (LFTs) exhibit high trading performance, despite the difference in their trading styles; HFTs attempt to maximize their trading efficiency by reducing risk, whereas LFTs make their profit by taking risk.

DOI： 10.1371/journal.pone.0208332

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society (APS)  

DOI： 10.1103/physreve.98.052317

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その他リンク： http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevE.98.052317/fulltext

担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

We introduce a systematic method to estimate an economic indicator from the Japanese government by analyzing big Japanese blog data. Explanatory variables are monthly word frequencies. We adopt 1352 words in the section of economics and industry of the Nikkei thesaurus for each candidate word to illustrate the economic index. From this large volume of words, our method automatically selects the words which have strong correlation with the economic indicator and resolves some difficulties in statistics such as the spurious correlation and overfitting. As a result, our model reasonably illustrates the real economy index. The announcement of an economic index from government usually has a time lag, while our proposed method can be real time.

DOI： 10.3390/e20110852

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physa.2018.06.002

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

DOI： 10.3390/e20070511

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-018-23675-x

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society (APS)  

DOI： 10.1103/PhysRevLett.120.138301

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0185712

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担当区分：最終著者,　責任著者   掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/e19080417

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0180863

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Physical Society of Japan  

DOI： 10.7566/jpscp.16.011013

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Physical Society of Japan  

DOI： 10.7566/jpscp.16.011004

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Physical Society of Japan  

DOI： 10.7566/jpscp.16.011011

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Physical Society of Japan  

DOI： 10.7566/jpscp.16.011003

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-017-05362-5

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/1742-5468/aa6ddb

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0177652

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1038/s41598-017-00242-4

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記述言語：日本語   出版者・発行元：国立研究開発法人 科学技術振興機構  

<p>インターネットという情報の巨大な伝送装置を得，おびただしい量の情報に囲まれることになった現代。実体をもつものの価値や実在するもの同士の交流のありようにも，これまで世界が経験したことのない変化が訪れている。本連載では哲学，デジタル・デバイド，サイバーフィジカルなどの諸観点からこのテーマをとらえることを試みたい。「情報」の本質を再定義し，情報を送ることや受けることの意味，情報を伝える「言葉」の役割や受け手としてのリテラシーについて再考する。</p><p>第5回は，サイバー空間における情報拡散の推移がテーマ。ある単語の出現数やその減衰を数理モデルで表し，科学的にシミュレーションすることから何がわかるのか。</p>

DOI： 10.1241/johokanri.60.512

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I028534383

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Physical Society of Japan  

Proceedings of the Asia-Pacific Econophysics Conference 2016 — Big Data Analysis and Modeling toward Super Smart Society — (APEC-SSS2016)

DOI： 10.7566/JPSCP.16.011014

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16K16016/

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Physical Society of Japan  

Proceedings of the Asia-Pacific Econophysics Conference 2016 — Big Data Analysis and Modeling toward Super Smart Society — (APEC-SSS2016)

DOI： 10.7566/JPSCP.16.011008

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16K16016/

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the Physical Society of Japan  

Proceedings of the Asia-Pacific Econophysics Conference 2016 — Big Data Analysis and Modeling toward Super Smart Society — (APEC-SSS2016)

DOI： 10.7566/JPSCP.16.011012

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16K16016/

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevE.94.052317

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0157653

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掲載種別：研究論文（学術雑誌）  

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記述言語：日本語   出版者・発行元：国立研究開発法人 科学技術振興機構  

DOI： 10.1241/johokanri.59.271

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0142685

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevE.92.042811

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記述言語：英語   出版者・発行元：Springer International Publishing  

DOI： 10.1007/978-3-319-20591-5

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記述言語：英語   出版者・発行元：IEEE  

To examine number fluctuations in online social media, we focus on the daily appearances of adjectives, adnominal particles, and conjunctions in a Japanese blog space. We show that a non-trivial fluctuation scaling law exists between the standard deviation and the mean. When the number of appearances becomes larger, the standard deviation linearly increases. We introduce a random posting (RP) model, which is inspired by the random diffusion model, to reproduce the observed scaling law. We confirm that the RP model can estimate number fluctuations in a Japanese blog space from both analytical and simulated results.

DOI： 10.1109/ICNF.2015.7288568

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Physical Society  

DOI： 10.1103/PhysRevE.91.042815

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0119979

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担当区分：筆頭著者,　最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0121443

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevE.91.042815

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer International Publishing  

DOI： 10.1007/978-3-319-20591-5_18

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer International Publishing  

DOI： 10.1007/978-3-319-20591-5_10

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

記述言語：英語   掲載種別：論文集(書籍)内論文   出版者・発行元：Springer  

DOI： 10.1007/978-3-319-20591-5_1

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer International Publishing  

DOI： 10.1007/978-3-319-20591-5_11

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-26310207/

記述言語：英語   出版者・発行元：Springer International Publishing  

DOI： 10.1007/978-3-319-20591-5_3

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記述言語：日本語   出版者・発行元：日本シミュレーション学会  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/00949655.2013.781603

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0100338

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s10955-014-0956-4

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevLett.112.098703

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記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.69.2.2.0_156_2

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掲載種別：研究論文（学術雑誌）  

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-24540395/

掲載種別：研究論文（学術雑誌）  

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-25750130/

記述言語：英語  

DOI： 10.1002/cplx.21452

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physa.2012.10.020

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevE.87.012805

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記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.68.2.2.0_246_2

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記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.68.2.2.0_245_3

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記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.68.1.2.0_405_3

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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出版者・発行元：National Bureau of Economic Research  

DOI： 10.3386/w18541

DOI： 10.1016/j.jimonfin.2021.102502_references_DOI_4LN1KJmwn31QN3Q50tInA7YSHyh

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media {LLC}  

DOI： 10.1140/epjst/e2012-01654-7

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.irfa.2011.06.010

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-24223003/

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevLett.108.168701

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1088/1367-2630/14/4/043034

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出版者・発行元：World Scientific Pub Co Pte Lt  

<jats:p> Non-trivial autocorrelation in up-down statistics in financial market price fluctuation is revealed by a multi-scale runs test(Wald-Wolfowitz test). We apply two models, a stochastic price model and dealer model to understand this property. In both approaches we successfully reproduce the non-stationary directional price motions consistent with the runs test by tuning parameters in the models. We find that two types of dealers exist in the markets, a short-time-scale trend-follower and an extended-time-scale contrarian who are active in different time periods. </jats:p>

DOI： 10.1142/s2010194512007830

DOI： 10.1080/00949655.2013.781603_references_DOI_JDpVNwnMU0TacpgVRvNoTcnEi70

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掲載種別：研究論文（学術雑誌）   出版者・発行元：World Scientific Pub Co Pte Lt  

<jats:p> We analyze Japanese inter-firm network data showing scale-free properties as an example of a real complex network. The data contains information on money flow (annual transaction volume) between about 7000 pairs of firms. We focus on this money-flow data and investigate the correlation between various quantities such as sales or link numbers. We find that the flux from a buyer to a supplier is given by the product of the fractional powers of both sales with different exponents. This result indicates that the principle of detailed balance does not hold in the real transport of money; therefore, random walk type transport models such as PageRank are not suitable. </jats:p>

DOI： 10.1142/s2010194512007805

DOI： 10.1103/physreve.91.042815_references_DOI_1uXEyc2U1nSQSEC1gP9mNJK2DEI

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-24540395/

記述言語：日本語   出版者・発行元：The Japanese Society for Artificial Intelligence  

The dealer model is an agent based model that simulates the simplified dealer's behavior and satisfies various empirical laws of the foreign exchange markets by tuning major three parameters. In this study,we improve the dealer model to satisfy a newly established empirical law about widening of spread as a response to big market price changes. As a result when a big news occurs and the market becomes turbulent, this new model can reproduce broadening of distribution of price change.In a peculiar price change of official intervention in the foreign exchange market by Bank of Japan, this model can be used for estimation of strategies of intervention and responses of the market.

DOI： 10.1527/tjsai.27.365

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記述言語：日本語   掲載種別：研究論文（その他学術会議資料等）  

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出版者・発行元：IEEE  

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その他リンク： http://dblp.uni-trier.de/db/conf/fusion/fusion2012.html#conf/fusion/YuraTTN12

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1080/14697681003792237

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記述言語：英語  

DOI： 10.1143/ptps.194.202

DOI： 10.1371/journal.pone.0246884_references_DOI_DgKwlEOgcqmwZmpFBXy7gIT4m3x

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その他リンク： http://dl.ndl.go.jp/info:ndljp/pid/10887536

記述言語：日本語   出版者・発行元：一般社団法人 システム制御情報学会  

DOI： 10.11509/isciesci.56.10_536

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I023997648

記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.67.1.2.0_380_1

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記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.67.2.2.0_236_2

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記述言語：日本語   出版者・発行元：一般社団法人 システム制御情報学会  

DOI： 10.11509/isciesci.56.10_517

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I023997597

記述言語：英語   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.physa.2010.09.032

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記述言語：英語  

DOI： 10.1109/icnf.2011.5994382

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記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.66.2.2.0_276_4

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記述言語：英語  

DOI： 10.1007/s11403-010-0066-6

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その他リンク： http://link.springer.com/article/10.1007/s11403-010-0066-6/fulltext.html

記述言語：英語  

DOI： 10.1007/s11403-010-0072-8

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1142/S0219635210002469

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出版者・発行元：IOP Publishing  

We have analyzed the lifetime distributions of more than 0.7 million products sold across approximately 400 Japanese supermarkets. The distributions are well approximated by an exponential function for products with lifetimes longer than 1000 days, implying that the manufacturers' decisions about whether to continue production are purely random. However, the distributions tend to deviate from an exponential distribution for products with lifetimes shorter than 1000 days. Specifically, the distributions for food products exhibit a quicker decay in a short time scale, suggesting the existence of competing products during the initial stages of the product lifecycle. On the other hand, the distributions for toiletry products exhibit a slower decay in a short time scale.

DOI： 10.1088/1742-6596/221/1/012018

DOI： 10.1109/bigdata.2016.7840887_references_DOI_c8mr8abJy3XJKW75nrkXoQlkCp

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記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）   出版者・発行元：物性研究刊行会  

この論文は国立情報学研究所の電子図書館事業により電子化されました。
ポスターセッション

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その他リンク： http://hdl.handle.net/2433/169211

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Physics Publishing  

DOI： 10.1088/1742-6596/221/1/012012

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記述言語：英語   出版者・発行元：Springer Japan  

DOI： 10.1007/978-4-431-53853-0-5

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記述言語：英語   出版者・発行元：IOP Publishing  

We numerically analyze an artificial market model consisted of N dealers with time dependent stochastic strategy. Observing the change of market price statistics for different values of N, it is shown that the statistical properties are almost same when the dealer number is larger than about 30.

DOI： 10.1088/1742-6596/221/1/012015

DOI： 10.1527/tjsai.27.365_references_DOI_PTs4sDjf3LTO1RxwrEwueDLVFjV

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

We observe the statistical properties of blogs that are expected to reflect social human interaction. Firstly, we introduce a basic normalization preprocess that enables us to evaluate the genuine word frequency in blogs that are independent of external factors such as spam blogs, server-breakdowns, increase in the population of bloggers, and periodic weekly behaviors. After this process, we can confirm that small frequency words clearly follow an independent Poisson process as theoretically expected. Secondly, we focus on each blogger's basic behaviors. It is found that there are two kinds of behaviors of bloggers. Further, Zipf's law on word frequency is confirmed to be universally independent of individual activity types.
10 pages, 14 figures

DOI： 10.1007/s11403-010-0065-7

DOI： 10.48550/arxiv.0906.1744

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その他リンク： http://link.springer.com/article/10.1007/s11403-010-0065-7/fulltext.html

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：一般社団法人 日本応用数理学会  

Firms build business relationships during economic activities. We empirically analyze an inter-firm network consisting of about one million firms and four million directed links by evaluating PageRank and specifying network motifs. The topology of the network exhibits both small-world and scale-free properties. By comparing with randomized networks, we find that PageRank correlates significantly with the growth rate of the firm. By specifying network motifs, which are small subgraphs that occur more frequently than expected in a randomly generated network, we find that V-shaped triads are network motifs, while feedforward and feedback loop are anti-motifs. By defining roles in the subgraph according to structural equivalence, we also detect the significance profile of roles characterizing the industry sector. The taxonomy of industries obtained from the profiles is economically meaningful. These empirical findings provide a valuable insight into the relationship between the network structure and the economic function.

DOI： 10.11540/bjsiam.20.3_223

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Physics Publishing  

DOI： 10.1088/1742-6596/221/1/012013

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Institute of Physics Publishing  

DOI： 10.1088/1742-6596/221/1/011001

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevE.80.056110

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1103/PhysRevE.79.051120

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語  

DOI： 10.1143/ptps.179.1

DOI： 10.1080/00949655.2013.781603_references_DOI_Wk37HDmaKuPOLiDBjrXSAlmmvrG

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出版者・発行元：Springer  

DOI： 10.1007/978-0-387-30440-3_223

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記述言語：英語  

DOI： 10.1143/ptps.179.157

DOI： 10.1007/978-4-431-55390-8_2_references_DOI_O2pC5t5ZnRy6Kh8pivvMu1yR7XM

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I10225456

記述言語：英語  

DOI： 10.1143/ptps.179.71

DOI： 10.48550/arxiv.0905.2474

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I10225432

記述言語：英語  

DOI： 10.1143/ptps.179.8

DOI： 10.1016/j.physrep.2021.10.005_references_DOI_HnfqK45fFtLkI46ESNFIkKQ1fyM

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I10225408

記述言語：英語  

DOI： 10.1016/j.physa.2008.01.059

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1140/epjb/e2008-00155-4

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出版者・発行元：Springer Science and Business Media LLC  

We empirically investigate price fluctuations of yen-dollar exchange rate using the high-frequency data recorded in the electronic broking system for seven-year period. The distribution of quote price changes has symmetric fat-tails approximated by a power law; however, that of deal price is asymmetrical. The autocorrelation function and diffusion of price changes indicate that quote price exhibits anti-correlation feature in short time scale, whereas deal price is essentially uncorrelated. The bid-ask spread shows power-law distribution and long range temporal correlations similar to that observed in absoute price changes.

DOI： 10.1007/s11403-008-0033-7

DOI： 10.1016/j.irfa.2011.06.010_references_DOI_Il7aCMbJurlaGWSCe7X72CYAkMM

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その他リンク： http://link.springer.com/article/10.1007/s11403-008-0033-7/fulltext.html

記述言語：英語  

DOI： 10.1016/j.physa.2007.04.093

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出版者・発行元：Elsevier BV  

We introduce a deterministic dealer model which implements most of the empirical laws, such as fat tails in the price change distributions, long term memory of volatility and non-Poissonian intervals. We also clarify the causality between microscopic dealers' dynamics and macroscopic market's empirical laws.
10pages, 5figures, 1table, Proceedings of APFA5

DOI： 10.1016/j.physa.2007.02.027

DOI： 10.48550/arxiv.physics/0608099

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記述言語：英語  

DOI： 10.1016/j.physa.2007.02.026

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記述言語：英語   出版者・発行元：Elsevier BV  

Abstract By using the historical data from the Japanese banks’ database at “The Bankers Library” of Japanese Banker Association, we analyze the historical network of banks from 1868 to 2006. Firstly, we define a bank every year by a particle and draw a space–time evolution process of merger, division, establishment, and failure by a tree diagram structure. We found that the distribution of the tree basin size of real data and simulation result are mostly fitting well. Secondly, we analyze the raw data of financial statements of banks collected by the National Diet library. We confirm that the distributions of the amount of deposits have fat-tail every year, however, small deviations are observed relating to governmental policy.

DOI： 10.1016/j.physa.2007.04.098

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記述言語：英語   出版者・発行元：Elsevier BV  

Based on the new type of random walk process called the Potentials of Unbalanced Complex Kinetics (PUCK) model, we theoretically show that the price diffusion in large scales is amplified 2/(2 + b) times, where b is the coefficient of quadratic term of the potential. In short time scales the price diffusion depends on the size M of the super moving average. Both numerical simulations and real data analysis of Yen-Dollar rates are consistent with theoretical analysis.
8 pages, 4 figures, Proceedings of APFA5

DOI： 10.1016/j.physa.2007.02.049

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記述言語：英語   出版者・発行元：Elsevier BV  

Abstract We show that random walks in a moving potential function, with its center at the moving average of market prices, are represented in the form of the self-modulation model. From this point of view we confirm the existence of non-trivial autocorrelation in real market price changes. By generalizing the formulation of potential function we prove that the ARCH model belongs to the special case of random walk in an asymmetric potential with randomly changing coefficient.

DOI： 10.1016/j.physa.2007.04.094

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physa.2006.04.113

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physa.2006.04.041

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記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）   出版者・発行元：物性研究刊行会  

近年,高頻度時系列データを用いた解析が進み,様々な市場の統計性が明らかになった.そこで,この統計性を再現する市場モデルの構築が期待されるが,そのようなモデルはまだない.本研究では,高安らによって提案された,閾値型のディーラーモデルを改良することにより,為替市場の統計性を幅広く再現するモデルを構築した.
この論文は国立情報学研究所の電子図書館事業により電子化されました。
研究会報告

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その他リンク： http://hdl.handle.net/2433/110550

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）   出版者・発行元：物性研究刊行会  

金融市場での価格の動きは、時間反転させても統計性は変わらないと仮定されることがあるが、実際には異なっている。我々は、時間方向の正しい外国為替レートと時間を反転させたレートを用いて、金融市場に潜む時間の矢の存在を示す。正しい時間方向のレートでは、急激な変動後に揺らぎが増加するが、時間反転したレートでは揺らぎが減少するという、統計性の違いを見出すことができる。
この論文は国立情報学研究所の電子図書館事業により電子化されました。
研究会報告

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I8029553

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physa.2005.08.079

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16540346/

記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physa.2005.04.026

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記述言語：英語  

DOI： 10.1002/dac.722

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記述言語：英語  

DOI： 10.1016/j.physa.2004.06.118

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記述言語：英語   出版者・発行元：Wiley  

DOI： 10.1002/ecja.1187

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.physa.2003.10.006

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記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）   出版者・発行元：物性研究刊行会  

平均場近似のアイデアを用いて企業所得分布におけるPower-Law発生メカニズムを明らかにする。膨大な企業財務データから企業所得は物理学で用いられる乗算ノイズを持つ離散Langevin方程式によって記述されることを示す。Zipf則を30年間維持している日本企業では前年度の所得が統計的に今年度の所得に依存していないという経験則から所得分布のべき指数を理論的に示し、アメリカやイギリスの所得分布については数値計算により示す。
この論文は国立情報学研究所の電子図書館事業により電子化されました。

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I6833596

記述言語：日本語   掲載種別：研究論文（大学，研究機関等紀要）   出版者・発行元：物性研究刊行会  

自己変調モデルとは、自分の履歴の移動平均値に対して乗算型でランダムに値が変化していくような確率過程である。金融市場の取引間隔のような点過程の場合には、間隔の分布がベキ乗則に従うことやパワースペクトルが1/fに従うことが厳密に証明できる。自分の履歴にしたがって未来の振る舞いが影響を受けるため、結果として、長時間相関を持つようになり、定常過程と非定常過程のちょうど境目としての振る舞いを示すのである。市場は、直近の影響を受けやすいので、自己変調モデルがよく当てはまる典型的な例であるが、経済現象以外にもいろいろな応用が考えられている。
この論文は国立情報学研究所の電子図書館事業により電子化されました。

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I6833628

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

We introduce an autoregressive-type model of prices in financial market taking into account the self-modulation effect. We find that traders are mainly using strategies with weighted feedbacks of past prices. These feedbacks are responsible for the slow diffusion in short times, apparent trends and power law distribution of price changes.
4 pages, 5 figures, submitted to Physica A

DOI： 10.1016/j.physa.2004.06.145

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その他リンク： https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16540346/

記述言語：英語   出版者・発行元：一般社団法人情報処理学会  

We propose a new TCP optimization scheme for improving TCP performance over congested networks. The scheme which we name LEAP leaps a data segment for retransmission and transmits a new data segment when ACK segment loss is suspected. LEAP is based on judgment whether retransmission of a data segment is caused by a data segment loss or an ACK segment loss. According to our simulation results LEAP eliminates nearly all duplicated segments in heavily congested networks involving multiple connections. Additionally by avoiding such duplicated segments LEAP drastically decreases the number of total transmitted segments in each connection. Our results show that LEAP improves overall network utilization more than 120% higher than conventional TCP variants under congested networks.We propose a new TCP optimization scheme for improving TCP performance over congested networks. The scheme, which we name LEAP, leaps a data segment for retransmission and transmits a new data segment when ACK segment loss is suspected. LEAP is based on judgment whether retransmission of a data segment is caused by a data segment loss or an ACK segment loss. According to our simulation results LEAP eliminates nearly all duplicated segments in heavily congested networks involving multiple connections. Additionally by avoiding such duplicated segments LEAP drastically decreases the number of total transmitted segments in each connection. Our results show that LEAP improves overall network utilization more than 120% higher than conventional TCP variants under congested networks.

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その他リンク： http://id.nii.ac.jp/1001/00010881/

出版者・発行元：Springer Japan  

DOI： 10.1007/978-4-431-53947-6_21

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：電子情報通信学会  

イメージセンサ上に情報処理機能の一部を取り込むVision Chipが広く研究されているが,ロボットビジョンなどで必要な画像の「意味」を抽出しようとするものはほとんどない.本論文では,画像の「意味」を出力とするイメージセンサとして,画像中の動く輝点の速度と方向を出力とするイメージセンサのための新規アーキテクテャの提案とその基礎的な検討を行う.この輝点の方向検出の際に,画素を格子状に並べる通常の構成で問題となる方向の特異性を解消し,任意方向の検出が可能となるアーキテクヂャの提案とその基礎的な検討を行う.

DOI： 10.24517/00007384

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その他リンク： http://hdl.handle.net/2297/3004

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語  

DOI： 10.1016/S0378-4371(02)01958-1

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記述言語：英語  

DOI： 10.1016/S0378-4371(02)01881-2

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記述言語：英語  

DOI： 10.1016/S0378-4371(03)00003-7

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記述言語：英語   出版者・発行元：Japanese Circulation Society  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1007/978-4-431-53947-6_3

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記述言語：英語   出版者・発行元：Springer Japan  

DOI： 10.1007/978-4-431-53947-6_23

DOI： 10.1007/978-3-319-08473-2_11_references_DOI_B8EQNXSxfWKjvemAfCaYf3DtSds

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記述言語：日本語   出版者・発行元：映像情報メディア学会  

イメージセンサ上に情報処理機能の一部をとりこむVisionChipが広く研究されているが、ロボットビジョンなどで必要な画像の「意味」を抽出しようとするものはほとんどない。本稿では、画像の「意味」を出力とするイメージセンサとして、画像中の動く輝点の速度と方向を出力とするイメージセンサのための新規アーキテクチャの提案とその基礎的な検討を行なう。この輝点の方向検出の際に、画素を格子状に並べる通常の構成で問題となる方向の特異性を解消し、任意方向の検出が可能となるアーキテクチャの提案とその基礎的な検討を行なう。

DOI： 10.11485/itetr.26.42.0_23

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その他リンク： http://hdl.handle.net/2297/3532

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/S0378-4371(02)00598-8

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記述言語：英語  

DOI： 10.1016/S0378-4371(02)00561-7

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記述言語：英語   出版者・発行元：Springer  

Following the work of Okuyama, Takayasu and Takayasu [Okuyama, Takayasu and Takayasu 1999] we analyze huge databases of Japanese companies' financial figures and confirm that the Zipf's law, a power law distribution with the exponent -1, has been maintained over 30 years in the income distribution of Japanese companies with very high precision. Similar power laws are found not only in income distribution of company's income, but also in the distributions of capital, sales and number of employees. From the data we find an important time evolutionary property that the growth rate of income is approximately independent of the value of income, namely, small companies and large ones have similar statistical chances of growth. This observational fact suggests the applicability of the theory of multiplicative stochastic processes developed in statistical physics. We introduce a discrete version of Langevin equation with additive and multiplicative noises as a simple time evolution model of company's income. We test the validity of the Takayasu-Sato-Takayasu condition [Takayasu, Sato and Takayasu 1997] for having an asymptotic power law distribution as a unique statistically steady solution. Directly estimated power law exponents and theoretically evaluated ones are compared resulting a reasonable fit by introducing a normalization to reduce the effect of gross economic change.
Empirical science of financial fluctuations: the advent of econophysics/ Hideki Takayasu (ed.), Proceeding of a workshop hosted by the Nihon Keizai Shimbun, Inc., and held in Tokyo, Nov. 15-17, 2000

DOI： 10.1007/978-4-431-66993-7_35

DOI： 10.48550/arxiv.cond-mat/0308365

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出版者・発行元：Springer Japan  

DOI： 10.1007/978-4-431-66993-7_3

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

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DOI： 10.1016/S0378-4371(00)00452-0

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記述言語：英語  

DOI： 10.1142/s0218348x0000038x

DOI： 10.48550/arxiv.cond-mat/0006038

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記述言語：英語  

DOI： 10.1016/S0378-4371(99)00499-9

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記述言語：英語   出版者・発行元：Elsevier BV  

Abstract Fluctuations of information flow in a public domain of the Internet are analyzed in view of statistical physics. It is shown that the characteristics of the massive traffics can be well described by the framework of dynamic phase transition between sparse and congested phases.

DOI： 10.1016/S0378-4371(99)00398-2

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記述言語：英語  

DOI： 10.1016/S0378-4371(99)00076-X

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/S0378-4371(99)00086-2

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出版者・発行元：World Scientific Pub Co Pte Lt  

<jats:p> An elastic block lattice model is proposed to simulate the spatio-temporal seismicity and stress patterns in the Earth's brittle crust. The famous Gutenberg-Richter magnitude-frequency law in seismology is reproduced. The synthetic catalogs generated by this model are analyzed by using a linked stress release model, which incorporates the stress transfer and spatial interactions. The results highlight the triggering mechanism of earthquake occurrence and the evidence that the crust may lie in a near-critical or self-organized critical state due to the long-range spatial interaction of elastic stress. The spatio-temporal complexity of seismicity is closely related to both nonlinear dynamics of faults and heterogeneities in a seismic region. </jats:p>

DOI： 10.1142/s0218348x9900030x

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出版者・発行元：World Scientific Pub Co Pte Lt  

<jats:p> We have developed an approach which allows the determination of relative congestion levels on nodes of TCP/IP computer network by observing test packet round trip time sequences for a series of routers located along the same path. We have also demonstrated the existence of strong spatial correlation of congestion levels. Propagation of congestion between neighboring routers can be observed directly. With increasing network load, distribution of congestion duration times changes from exponential to a distribution falling off slower than power law, via power law distribution. We thus conclude that direct observations of network congestion agree with predictions of a model based on contact process. </jats:p>

DOI： 10.1142/s0218348x99000049

DOI： 10.1109/waina.2013.180_references_DOI_9VBG6PXF2OkxatPdVAmusNzPxGC

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記述言語：英語  

DOI： 10.1016/S0375-9601(98)00176-5

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/S0378-4371(97)00659-6

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記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

インターネットにおける渋滞は, ネットワーク内のパケットの密度が増加することに伴い引き起こされる臨界現象を伴う相転移現象とみなせることがわかった. この相転移現象を引き起こす本質的なメカニズムは, 接触過程によるルータ間の渋滞の伝播であり, 臨界点においては1/fゆらぎが観測される.

DOI： 10.11316/butsuri1946.53.346

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I4480459

記述言語：英語  

DOI： 10.1103/PhysRevLett.79.966

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出版者・発行元：Springer Japan  

DOI： 10.1007/978-4-431-66862-6_16

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DOI： 10.1016/S0378-4371(96)00189-6

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1111/j.1525-1594.1996.tb04539.x

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DOI： 10.1209/epl/i1996-00305-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier {BV}  

DOI： 10.1016/0928-4680(95)00025-v

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1111/j.1525-1594.1995.tb02413.x

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記述言語：英語  

DOI： 10.1142/S0217979294001676

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DOI： 10.1142/S0218348X93000885

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DOI： 10.1016/0378-4371(93)90591-Q

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語  

DOI： 10.1016/0378-4371(92)90122-7

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記述言語：英語  

DOI： 10.1103/PhysRevA.46.782

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記述言語：英語  

DOI： 10.1103/PhysRevA.45.8965

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DOI： 10.1103/PhysRevA.46.782

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記述言語：英語  

DOI： 10.1007/bf01053751

DOI： 10.1143/jpsj.63.3629_references_DOI_9VW2rKKNUxcjPn206SUAo3fygAJ

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その他リンク： http://link.springer.com/article/10.1007/BF01053751/fulltext.html

記述言語：英語  

DOI： 10.1103/PhysRevA.42.7087

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記述言語：英語  

DOI： 10.1103/PhysRevA.39.4345

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記述言語：英語  

DOI： 10.1016/0375-9601(88)90507-5

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記述言語：英語  

DOI： 10.1016/0375-9601(88)91040-7

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記述言語：日本語  

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記述言語：日本語  

DOI： 10.1241/johokanri.59.271

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記述言語：日本語  

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その他リンク： http://id.ndl.go.jp/bib/026736841

記述言語：日本語  

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