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SHIMADA Yutaka
| Mathematics, Electronics and Informatics Division | Associate Professor |
| Department of Information and Computer Sciences |
Performance information
■ Paper- Analysis of the Effect of Music on Audience Behavior at a Concert
Ban Takahiro; Kimura Manami; Nomura Ryota; Shimada Yutaka
Journal of Signal Processing, Volume：28, Number：4, First page：191, Last page：195, Jul. 2024, [Reviewed]
In recent years, collective human behavior has been investigated by using small wireless sensors in several fields including medical and educational settings, where individuals' body movements and their proximity are observed and analyzed. These data have been mainly collected in several educational and medical settings, and few data observed in other situations are thus far available. We here investigate the collective human behavior of audience members during a live music concert by observing their body movements. We examine how different pieces of music to which audience members listen affect their body movements, using the time series data of the magnitude of body movements and the similarities in the body movements of the audience members. The results suggest that fast-tempo music can lead to an increase in the magnitude of body movements of audience members. Moreover, slow-tempo music might cause an increase in similarity between the body movements of the audience members.
Research Institute of Signal Processing, Japan, English
DOI：https://doi.org/10.2299/jsp.28.191
DOI ID：10.2299/jsp.28.191, ISSN：1342-6230, eISSN：1880-1013 - Construction of Distributed Computer Network by Mesh-type NFS Home Sharing in Group of macOS Machines—Fusion of Legacy and Modern Unix Technologies—
YAMADA Taiji; TAKAHASHI Jun; SHIMADA Yutaka; IKEGUCHI Tohru
IEICE ESS Fundamentals Review, Volume：18, Number：1, First page：7, Last page：28, Jul. 2024
NFS (Network File System) is a distributed file system used in Unix. In the 1990s, when managing and operating computer networks using Unix, it was common that users' home directories were shared through NFS from every machine where they logged into. Such an environment in which users' home directories can be referred to at any time within a local network has various advantages, for example, users on the local network can share technology information with each other and use computer resources in the local network. However, now that storage technologies have evolved from HDDs to SSDs, even if a network with a high transmission speed, e.g., 10 GbE, is used, NFS file sharing itself becomes a bottleneck in terms of access speed. Therefore, it is difficult to bring out the performance of faster machines. Therefore, we developed a network environment in which users' home directories can be shared within a local network without reducing the access speed of SSDs on the console. Specifically, we realized a distributed computer network using mesh-type NFS home sharing in which each machine exports its home directory through NFS on macOS, a modern Unix. This article offers one of the technical solutions to this issue.
The Institute of Electronics, Information and Communication Engineers, Japanese
DOI：https://doi.org/10.1587/essfr.18.1_7
DOI ID：10.1587/essfr.18.1_7, eISSN：1882-0875 - A heuristic method for solving the Steiner tree problem in graphs using network centralities
Misa Fujita; Yutaka Shimada; Takayuki Kimura; Tohru Ikeguchi
PLOS ONE, Volume：19, Number：6, First page：e0303764, Last page：e0303764, Jun. 2024, [Reviewed]
We propose a heuristic method of using network centralities for constructing small-weight Steiner trees in this paper. The Steiner tree problem in graphs is one of the practical NP-hard combinatorial optimization problems. Given a graph and a set of vertices called terminals in the graph, the objective of the Steiner tree problem in graphs is to find a minimum weight Steiner tree that is a tree containing all the terminals. Conventional construction methods make a Steiner tree based on the shortest paths between terminals. If these shortest paths are overlapped as much as possible, we can obtain a small-weight Steiner tree. Therefore, we proposed to use network centralities to distinguish which edges should be included to make a small-weight Steiner tree. Experimental results revealed that using the vertex or the edge betweenness centralities contributes to making small-weight Steiner trees.
Public Library of Science (PLoS), Scientific journal
DOI：https://doi.org/10.1371/journal.pone.0303764
DOI ID：10.1371/journal.pone.0303764, eISSN：1932-6203 - Central emotions and hubs in a colexification network.
Mitsuki Fukuya; Tomoko Matsumoto; Yutaka Shimada; Tohru Ikeguchi
Scientific reports, Volume：13, Number：1, First page：21823, Last page：21823, Dec. 2023, [Reviewed], ［International magazine］
By focusing on colexification, we detected central emotions sharing semantic commonalities with many other emotions in terms of a semantic relationship of both similarity and associativity. In analysis, we created colexification networks from multiple languages by assigning a concept to a vertex and colexification to an edge. We identify concepts of emotions with a large weight in the colexification network and specify central emotions by finding hub emotions. Our resultant central emotions are four: "GOOD," "WANT," "BAD," and "LOVE."
English, Scientific journal
DOI：https://doi.org/10.1038/s41598-023-48922-8
DOI ID：10.1038/s41598-023-48922-8, PubMed ID：38071399, PubMed Central ID：PMC10710517 - A routing method with adaptively adjusting memory information based on local routing history
Takayuki Kimura; Yutaka Shimada
PLOS ONE, Volume：18, Number：4, First page：e0283472, Last page：e0283472, Apr. 2023, [Reviewed]
Finding the shortest paths for packets from sources to destinations in packet-switched communication networks is an inevitable problem in building a future high-speed information society. A routing method with memory information has already been proposed to alleviate the congestion of large volumes of packet flow. This routing method shows a high transmission completion rate even for large volumes of packet flows in communication networks with scale-free properties. However, the method exhibits poor performance for networks with local triangular connections and long distances between nodes. To overcome these problems, in this study, we first enhanced the routing performance of the conventional communication network models by using the betweenness centrality of nodes, which is one of the network centralities that measures the number of shortest paths that pass through each node in the networks. Subsequently, we adaptively changed the transmitting paths of packets by using only local information. Numerical simulations indicated that our routing method performs successfully for various topologies of communication networks by avoiding the congested node, and effectively using the memory information.
Public Library of Science (PLoS), Scientific journal
DOI：https://doi.org/10.1371/journal.pone.0283472
DOI ID：10.1371/journal.pone.0283472, eISSN：1932-6203 - Analyzing the relationships between tissue-specific gene expression and subgraphs in gene regulatory networks
Cham Haga; Shimada Yutaka
Nonlinear Theory and Its Applications, IEICE, Volume：13, Number：2, First page：415, Last page：420, Apr. 2022, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.1587/nolta.13.415
DOI ID：10.1587/nolta.13.415, eISSN：2185-4106 - Similarities of inter-point distance distributions on original and reconstructed attractors
Sawada Kazuya; Shimada Yutaka; Ikeguchi Tohru
Nonlinear Theory and Its Applications, IEICE, Volume：13, Number：2, First page：385, Last page：390, Apr. 2022, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.1587/nolta.13.385
DOI ID：10.1587/nolta.13.385, eISSN：2185-4106 - Investigation of the structural features of word co-occurrence networks with increasing numbers of connected words
Magishi Kihei; Matsumoto Tomoko; Shimada Yutaka; Ikeguchi Tohru
Nonlinear Theory and Its Applications, IEICE, Volume：13, Number：2, First page：343, Last page：348, Apr. 2022, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.1587/nolta.13.343
DOI ID：10.1587/nolta.13.343, eISSN：2185-4106 - Possibility of Reconstructing Nonlinear Dynamical System from Marked Point Process
Sawada Kazuya; Shimada Yutaka; Ikeguchi Tohru
Journal of Signal Processing, Volume：25, Number：4, First page：127, Last page：131, Jul. 2021, [Reviewed]
We can observe marked point processes in a wide variety of natural phenomena. Thus, it is important to establish theories and methods for analyzing such observed marked point processes. In a nonlinear time series analysis, the theories are the embedding theorems and the methods are the state space reconstruction from the observed time series. Although it has been revealed that we can reconstruct a state space from a point process without marked values, it has not been clarified yet whether we can reconstruct the state space from a marked point process. Therefore, in this study, we numerically investigated whether a state space could be reconstructed from a marked point process using a delayed coordinate system. To assess the issue, we evaluated the similarity between the interpoint distance distributions on an attractor of the original dynamical system that generated the marked point process and an attractor reconstructed from the marked point process. Results of numerical experiments show that the interpoint distance distributions in the original and reconstructed state spaces are similar, implying that it is possible to reconstruct nonlinear dynamical systems from the observed marked point processes.
Research Institute of Signal Processing, Japan, English
DOI：https://doi.org/10.2299/jsp.25.127
DOI ID：10.2299/jsp.25.127, ISSN：1342-6230, eISSN：1880-1013, CiNii Articles ID：130008060219 - Efficient routing strategy with transmission history information and its surrogate analysis
Akinori Yoshida; Yutaka Shimada; Takayuki Kimura
Physica A: Statistical Mechanics and its Applications, Volume：566, First page：125597, Last page：125597, Mar. 2021, [Reviewed]
Elsevier BV, English, Scientific journal
DOI：https://doi.org/10.1016/j.physa.2020.125597
DOI ID：10.1016/j.physa.2020.125597, ISSN：0378-4371 - Performance evaluation of chaotic random numbers generated from responses of integer logistic maps
Kanamaru Shiki; Shimada Yutaka; Fujiwara Kantaro; Ikeguchi Tohru
Nonlinear Theory and Its Applications, IEICE, Volume：12, Number：3, First page：489, Last page：499, 2021, [Reviewed]
One of the engineering applications of chaotic nonlinear dynamical systems is a pseudorandom number generator. Pseudorandom numbers generated from chaotic dynamical systems are called chaotic random numbers. A logistic map which exhibits a chaotic response can be used as such a chaotic random number. However, an important issue exists when we use such dynamical systems as a pseudorandom number generator by a digital computer: when the chaotic response of a logistic map is reproduced numerically, the number of iterations that the chaotic response is sustained depends on the precision of the numerical calculation, because the precision of the numerical calculation affects the size of the numerical error. In this paper, we extended the logistic map to an integer logistic map to reduce such numerical errors. We investigated the performance of chaotic random numbers obtained from the integer logistic map with varying numerical precisions and transforming them into binary random numbers. We then used NIST SP 800-22 to evaluate the performance of the random numbers. The results show that a numerical precision of 20 orders of magnitude or more is desirable to the generation of a well-performing chaotic random numbers from the response of the integer logistic map.
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.1587/nolta.12.489
DOI ID：10.1587/nolta.12.489, eISSN：2185-4106, CiNii Articles ID：130008060794 - Analysis on the mechanism of enhancing insulin secretion by TRPM2 channel in a pancreatic β-cell
Kasahara Kotaro; Shimada Yutaka; Fujiwara Kantaro; Ikeguchi Tohru
Nonlinear Theory and Its Applications, IEICE, Volume：12, Number：3, First page：500, Last page：511, 2021, [Reviewed]
It has been reported that the activation of the Ca2+-permeable transient receptor potential melastatin2 (TRPM2) channel enhances a pancreatic β-cell's insulin secretion. Further, it increases the resting potential, and prolongs the burst duration of the pancreatic β-cell. However, the mechanism by which the TRPM2 channel activation enhances insulin secretion is unknown. Therefore, in this paper, using a mathematical model that represents the dynamics of the membrane potential, we investigate the reproducibility of the results obtained from physiological experiments, and reveal the mechanism of enhancing insulin secretion. We demonstrate that the TRPM2 channel activation prolongs the burst duration when the TRPM2 reversal potential is close to the value observed in the physiological experiments. This could be a plausible theoretical explanation of the experimental value of the TRPM2 reversal potential. In addition, we reveal that the TRPM2 channel activates the voltage-dependent and Ca2+-sensitive channels with large conductance, thereby inducing insulin secretion.
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.1587/nolta.12.500
DOI ID：10.1587/nolta.12.500, eISSN：2185-4106, CiNii Articles ID：130008060793 - Detecting prediction limit of marked point processes using constrained random shuffle surrogate data
Yutaka Shimada; Kohei Yamamoto; Tohru Ikeguchi
Chaos: An Interdisciplinary Journal of Nonlinear Science, Volume：31, Number：1, First page：013122, Last page：013122, Jan. 2021, [Reviewed]
AIP Publishing, Scientific journal
DOI：https://doi.org/10.1063/5.0005267
DOI ID：10.1063/5.0005267, ISSN：1054-1500, eISSN：1089-7682 - Network structure detection using convergent cross mapping on multivariate time series
Kazuya Sawada; Yutaka Shimada; Tohru Ikeguchi
Nonlinear Theory and Its Applications, IEICE, Volume：11, Number：4, First page：422, Last page：432, 2020, [Reviewed], [Invited]
Institute of Electronics, Information and Communications Engineers (IEICE), Scientific journal
DOI：https://doi.org/10.1587/nolta.11.422
DOI ID：10.1587/nolta.11.422, ISSN：2185-4106, eISSN：2185-4106, Web of Science ID：WOS:000576676300005 - Chaos MIMO system with efficient use of information of bits
Ryo Yamazaki; Yutaka Shimada; Tohru Ikeguchi
Nonlinear Theory and Its Applications, IEICE, Volume：11, Number：4, First page：546, Last page：560, 2020, [Reviewed]
The multiple-input multiple-output (MIMO) system is one of the wireless communication methods that use multiple transmit and receive antennas. To ensure security on the physical layer and also to enhance channel coding efficiency, a chaos MIMO (C-MIMO) system was previously proposed. In this system, a chaotic dynamical system is used for modulation. In this paper, we revealed that the original C-MIMO system does not effectively use the information of bits that are used for modulation, which results in a difficulty in distinguishing encrypted symbols. To solve this issue, we propose a new modulation method for the C-MIMO system. We evaluated the performance of the proposed C-MIMO system and showed that the proposed C-MIMO system significantly improves block error rates.
IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, English, Scientific journal
DOI：https://doi.org/10.1587/nolta.11.546
DOI ID：10.1587/nolta.11.546, ISSN：2185-4106, Web of Science ID：WOS:000576676300014 - Formation mechanisms of local structures in language networks
Yutaka Shimada; Mayumi Tatara; Kantaro Fujiwara; Tohru Ikeguchi
EPL (Europhysics Letters), Volume：127, Number：5, First page：56003, Oct. 2019, [Reviewed], [Lead]
The small-world property has recently been observed in several language networks generated in terms of word co-occurrence. However, a syntactic interpretation of this universal property has not yet been clarified. This study aims to reveal the formation mechanism of local structures involving small-world properties of co-occurrence language networks. We analyse local structures of language networks with directed edges generated from five different languages, where the directed edges provide word-order information. The results show that the following three syntactic properties play a leading role in the formation of the local structure of a language network: i) agglutination of words, ii) changes in the positions of words, and iii) basic word orders of languages. We further show that a common formation mechanism exists in local structures, even though the syntactic rules vary between the considered languages. These syntactic properties potentially drive the small-world property of language networks. Copyright (C) EPLA, 2019.
IOP Publishing, English, Scientific journal
DOI：https://doi.org/10.1209/0295-5075/127/56003
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85075147428&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85075147428&origin=inward
DOI ID：10.1209/0295-5075/127/56003, ISSN：0295-5075, eISSN：1286-4854, SCOPUS ID：85075147428, Web of Science ID：WOS:000504868700003 - Person Re-identification for Estimating Bus Passenger Flow
Yutaka Shimada; Motoki Takagi; Yukinobu Taniguchi
Proceedings of IEEE 2nd International Conference on Multimedia Information Processing and Retrieval, MIPR 2019, First page：169, Last page：174, Apr. 2019, [Reviewed], [Invited], [Lead]
© 2019 IEEE. A bus transportation system provides social and economic advantages and plays a key role in our daily lives. This study aims at utilizing videos recorded by cameras installed in buses to improve and optimize bus services, where the required basic and important information is bus passenger flow. We here consider the problem of estimating the bus passenger flow as person re-identification problem on a bus. Then, we propose a method for improving the identification accuracy of persons by using bus-specific properties. Results show that the proposed method is simple but effective in solving the person re-identification problem on buses.
IEEE, English, International conference proceedings
DOI：https://doi.org/10.1109/MIPR.2019.00037
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85065626286&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85065626286&origin=inward
DOI ID：10.1109/MIPR.2019.00037, SCOPUS ID：85065626286, Web of Science ID：WOS:000493730600030 - Tracking Temporal Networks by Means of Graph Distance Based on a Laplacian Matrix
Yutaka Shimada; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：585, Last page：586, 2019, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-14
DOI ID：10.34385/proc.48.A3L-C-14 - Estimation of Predictability of Marked Point Processes Using Constrained Random Shuffle Surrogate Data
Kohei Yamamoto; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：532, Last page：535, 2019, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-13
DOI ID：10.34385/proc.48.A3L-C-13 - Estimation of Neural Network Structure Using Inter-Spike Intervals
Kazuya Sawada; Yutaka Shimada; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, Volume：119, Number：19(NLP2019 1-17), First page：591, Last page：594, 2019, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-12
DOI ID：10.34385/proc.48.A3L-C-12, ISSN：0913-5685, J-Global ID：201902233829802473 - Effects of TRPM2 Channel on Insulin Secretion
Kotaro Kasahara; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：54, Last page：57, 2019, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-11
DOI ID：10.34385/proc.48.A3L-C-11 - Analysis of Structural Features of Musical Compositions Using Complex Network Theory
Fujia Mao; Yutaka Shimada; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：587, Last page：590, 2019, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-10
DOI ID：10.34385/proc.48.A3L-C-10 - A Method for Extracting Deterministic Properties of Nonlinear Time Series with a Variable Threshold
Shiki Kanamaru; Yutaka Shimada; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：536, Last page：539, 2019, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-9
DOI ID：10.34385/proc.48.A3L-C-9 - Estimation of Connections between Neurons only from Inter-Spike-Interval
Kazuya Sawada; Yutaka Shimada; and Tohru Ikeguchi
the 5th International Conference on Mathematical NeuroScience (ICMNS 2019), Volume：1, Number：1, 2019, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-8
DOI ID：10.34385/proc.48.A3L-C-8 - Analysis of synchronization of mechanical metronomes
Tohru Ikeguchi; Yutaka Shimada
Understanding Complex Systems, First page：141, Last page：152, 2019, [Reviewed]
© 2019, Springer Nature Switzerland AG. Synchronization phenomena are ubiquitous around us and are observed in various real systems, for example, hands clapping (rhythmic applause) at the concert hall, light emission of fireflies, callings of frogs, circadian rhythms, pendulum clocks, mechanical metronomes placed on a plate, pedestrians on a suspension bridge, water flowing out of plastic bottles connected by hoses, candle flames fluctuation. In this paper, we focused on the synchronization phenomena observed in a mechanical system: mechanical metronomes on a plate. In particular, we discussed how to construct a mathematical model, or the equations of motion, which describe dynamical behavior of synchronization of mechanical metronomes put on a plate hung by strings. We also investigated their dynamical behavior by solving the equations of motions numerically. In the numerical experiments, parameter values of the equations of motion are experimentally obtained from the experimental equipment. We found that synchronization behavior of mechanical metronomes depends on the following two factors: relation between the frequencies of the metronomes and the plate, and initial angles of the metronomes. We also found the individual difference of the metronomes strongly affects the final behavior. In addition, the results also indicate that if the number of mechanical metronomes increases, it becomes extremely harder to observe the in-phase synchronization until energy applied to the metronomes through spiral springs is exhausted.
International conference proceedings
DOI：https://doi.org/10.1007/978-3-030-10892-2_15
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85064933478&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85064933478&origin=inward
DOI ID：10.1007/978-3-030-10892-2_15, ISSN：1860-0832, eISSN：1860-0840, SCOPUS ID：85064933478 - Synaptic Dynamics in ISO by Dopaminergic Modulation and Inhibitory Synaptic Learnings
Tohru Ikeguchi; Yutaka Shimada; Kantaro Fujiwara; Sakura Rai; Toshihiro Kobayashi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：164, Last page：167, 2018, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-7
DOI ID：10.34385/proc.48.A3L-C-7 - Nonlinear Time Series Analysis on LOTO7
Shiki Kanamaru; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：430, Last page：433, 2018, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-6
DOI ID：10.34385/proc.48.A3L-C-6 - Nonlinear Analysis on Temporally High Resolution Data of Stock Markets in Japan
Kohei Yamamoto; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：434, Last page：437, 2018, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-5
DOI ID：10.34385/proc.48.A3L-C-5 - Investigation of ISO Generated by Dopaminergic Modulation and Inhibitory Synaptic Learning
Sakura Rai; Mayu Aoki; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
the 4th International Conference on Mathematical NeuroScience (ICMNS 2018), Volume：1, Number：1, 2018, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-4
DOI ID：10.34385/proc.48.A3L-C-4 - Temporal video alignment based on integrating multiple features by adaptive weighting
Taiki Sato; Yutaka Shimada; Yukinobu Taniguchi
2018 International Workshop on Advanced Image Technology (IWAIT), Jan. 2018, [Reviewed]
IEEE, International conference proceedings
DOI：https://doi.org/10.1109/iwait.2018.8369748
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85048826961&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85048826961&origin=inward
DOI ID：10.1109/iwait.2018.8369748, SCOPUS ID：85048826961 - Reproducing Infra-Slow Oscillations with Dopaminergic Modulation
Toshihiro Kobayashi; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Scientific Reports, Volume：7, Number：1, First page：2411, Dec. 2017, [Reviewed]
In the human brain, billions of neurons construct a neural network via synaptic connections. Neuronal excitation and inhibition are transmitted to other neurons through synapses via neurotransmitters. Dopamine is one of these neurotransmitters that plays a number of important roles. There are a variety of rhythms in the brain, such as alpha rhythm, beta rhythm, and so on. Infra-slow oscillation, ISO, is one of the rhythms observed in the brain, and ranges below 0.1 Hz. One of the key roles of dopamine is the generation of ISO in neural networks. Although the mechanism underlying the generation of ISO remains unknown, ISO can be generated by activation of the D1-type dopamine receptor. The D1-type receptor regulates spike timing-dependent plasticity (STDP), which is a learning rule of the change in synaptic weights. In this paper, to reproduce ISO in neural networks, we show that dopaminergic modulation of STDP is essential. More specifically, we discovered a close relationship between two dopaminergic effects: modulation of the STDP function and generation of ISO. We therefore, numerically investigated the relationship in detail and proposed a possible mechanism by which ISO is generated.
Springer Science and Business Media LLC, English, Scientific journal
DOI：https://doi.org/10.1038/s41598-017-02366-z
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85019750659&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85019750659&origin=inward
DOI ID：10.1038/s41598-017-02366-z, ISSN：2045-2322, eISSN：2045-2322, PubMed ID：28546544, SCOPUS ID：85019750659, Web of Science ID：WOS:000401962500015 - Izhikevichニューロンモデルにおけるカオス応答とカオス同期
内木 楓; 島田 裕; 藤原 寛太郎; 池口 徹
Volume：J100-A, Number：5, First page：195, Last page：204, May 2017, [Reviewed]
Scientific journal - Effect of Connectivity Weights of Inhibitory Neurons in Neuronal Avalanches
Mayu Aoki; Hideyuki Kato; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：29, First page：152, Last page：155, 2017, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.29.A2L-C-4
DOI ID：10.34385/proc.29.A2L-C-4, CiNii Articles ID：230000009391 - Chaotic Neurodynamical search with small number of neurons for solving QAP
Ohnishi Hikaru; Shimada Yutaka; Fujiwara Kantaro; Ikeguchi Tohru
Nonlinear Theory and Its Applications, IEICE, Volume：8, Number：3, First page：255, Last page：265, 2017, [Reviewed]
Quadratic Assignment Problem (QAP) is one of the combinatorial optimization problems which are classified into Nondeterministic Polynomial time solvable (NP)-hard problems. Therefore, it is important to develop algorithms for finding good approximate solutions in short time. In this paper, we proposed an algorithm for approximately solving QAP by using chaotic neurodynamics. The proposed algorithm has three characteristics. First, compared with the conventional method, the number of neurons was substantially reduced. Second, the effect of external inputs to neurons was changed. Third, a new parameter tuning method was introduced. As a result, our algorithm can find good solutions compared with the conventional method using chaotic neurodynamics.
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.1587/nolta.8.255
DOI ID：10.1587/nolta.8.255, ISSN：2185-4106, CiNii Articles ID：130006903507, Web of Science ID：WOS:000425331600008 - Symmetry of lyapunov exponents in bifurcation structures of one-dimensional maps
Yutaka Shimada; Emiko Takagi; Tohru Ikeguchi
Chaos, Volume：26, Number：12, First page：123119, Dec. 2016, [Reviewed], [Lead]
© 2016 Author(s). We observe a symmetry of Lyapunov exponents in bifurcation structures of one-dimensional maps in which there exists a pair of parameter values in a dynamical system such that two dynamical systems with these paired parameter values have the same Lyapunov exponent. We show that this is a consequence of the presence of an invariant transformation from a dynamical system with one of the two paired parameter values to that with another parameter value, which does not change m natures of dynamical systems.
AMER INST PHYSICS, English, Scientific journal
DOI：https://doi.org/10.1063/1.4972401
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85007403405&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85007403405&origin=inward
DOI ID：10.1063/1.4972401, ISSN：1054-1500, eISSN：1089-7682, SCOPUS ID：85007403405, Web of Science ID：WOS:000392001500019 - Graph distance for complex networks
Yutaka Shimada; Yoshito Hirata; Tohru Ikeguchi; Kazuyuki Aihara
Scientific Reports, Volume：6, First page：34944, Oct. 2016, [Reviewed], [Lead]
© 2016 The Author(s). Networks are widely used as a tool for describing diverse real complex systems and have been successfully applied to many fields. The distance between networks is one of the most fundamental concepts for properly classifying real networks, detecting temporal changes in network structures, and effectively predicting their temporal evolution. However, this distance has rarely been discussed in the theory of complex networks. Here, we propose a graph distance between networks based on a Laplacian matrix that reflects the structural and dynamical properties of networked dynamical systems. Our results indicate that the Laplacian-based graph distance effectively quantifies the structural difference between complex networks. We further show that our approach successfully elucidates the temporal properties underlying temporal networks observed in the context of face-to-face human interactions.
NATURE PUBLISHING GROUP, English, Scientific journal
DOI：https://doi.org/10.1038/srep34944
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84994045405&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84994045405&origin=inward
DOI ID：10.1038/srep34944, ISSN：2045-2322, eISSN：2045-2322, SCOPUS ID：84994045405, Web of Science ID：WOS:000385061400001 - Analysis on Differences of Japanese and English Languages by the Complex Network Theory
Mayumi Tatara; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on Nonlinear Theory and Its Applications, First page：137, Last page：140, 2016, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-4
DOI ID：10.34385/proc.48.A3L-C-4, CiNii Articles ID：230000009198 - Numerical Analysis on Synchronization of Four Metronomes
Yusuke Shiomi; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：48, First page：506, Last page：509, 2016, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.B3L-D-2
DOI ID：10.34385/proc.48.B3L-D-2, CiNii Articles ID：230000009211 - A Chaotic Search with the Effect of Wide Range Search for Solving QAP
Hikaru Ohnishi; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：48, First page：52, Last page：55, 2016, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A2L-D-5
DOI ID：10.34385/proc.48.A2L-D-5, CiNii Articles ID：230000009233 - Irregularity of Inter-Event Interval of Diastrophism
Keisuke Miyata; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：48, First page：141, Last page：144, 2016, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A3L-C-5
DOI ID：10.34385/proc.48.A3L-C-5, CiNii Articles ID：230000009253 - Analysis of Synaptic Dynamics During Infra-Slow Oscillation
Toshihiro Kobayashi; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：48, First page：261, Last page：264, 2016, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A4L-D-2
DOI ID：10.34385/proc.48.A4L-D-2, CiNii Articles ID：230000009273 - Which Vertices Affect the Spread of Disease in Temporal Networks?
Koshi Abe; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：48, First page：618, Last page：621, 2016, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.C1L-E-6
DOI ID：10.34385/proc.48.C1L-E-6, CiNii Articles ID：230000009445 - Synchronization in a Coupled Izhikevich Neuron Model
Kaede Naiki; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Volume：2016, Number：48, First page：257, Last page：260, 2016, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.48.A4L-D-1
DOI ID：10.34385/proc.48.A4L-D-1, ISSN：2189-700X, CiNii Articles ID：230000009272, CiNii Books ID：AA12732012 - Numerical analysis on behavior of coupled maps on regular ring lattice with high degrees
Yutaka Shimada; Tohru Ikeguchi
IFAC-PapersOnLine, Volume：28, Number：18, First page：239, Last page：244, Nov. 2015, [Reviewed], [Lead]
© 2015, IFAG (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Behavior of coupled dynamical systems strongly depends on network structures, i.e. how dynamical systems connect with each other. We here numerically show what happens when the degree (K) of regular ring lattice increases. In the ring lattice, it is known that the clustering coefficient (C) is 3(K - 2)/4(K - 1). This predicts that C becomes about 3/4, when K is sufficiently large. However, we find that this is not satisfied when K is large, because of the periodic boundary condition of the ring lattice. We further investigate how the change in C of the ring lattice affects behavior of coupled dynamical systems on the ring lattice.
International conference proceedings
DOI：https://doi.org/10.1016/j.ifacol.2015.11.043
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84992488225&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84992488225&origin=inward
DOI ID：10.1016/j.ifacol.2015.11.043, eISSN：2405-8963, SCOPUS ID：84992488225 - A Chaotic Search with Small Memory Consumption for Solving QAP
Hikaru Ohnishi; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：47, First page：610, Last page：613, 2015, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.47.B3L-E-1
DOI ID：10.34385/proc.47.B3L-E-1, CiNii Articles ID：230000008946 - STDP Learning Can Reproduce Infra-Slow Oscillation
Toshihiro Kobayashi; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：47, First page：447, Last page：450, 2015, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.47.B2L-C-2
DOI ID：10.34385/proc.47.B2L-C-2, CiNii Articles ID：230000009022 - Analysis on the Spread of Disease on Temporal Networks
Koshi Abe; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：47, First page：337, Last page：340, 2015, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.47.A5L-A-1
DOI ID：10.34385/proc.47.A5L-A-1, CiNii Articles ID：230000009070 - A Graph Laplacian Based Approach for Facilitating Synchronization in Networked Dynamical Systems
Yutaka Shimada; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：47, First page：856, Last page：859, 2015, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.47.C2L-E-4
DOI ID：10.34385/proc.47.C2L-E-4, CiNii Articles ID：230000009101 - Common Noise-Induced Synchronization of Chaotic Oscillators and Contraction Regions
Tsubasa Kawai; Yutaka Shimada; Kantaro Fujiwara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：47, First page：852, Last page：855, 2015, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.47.C2L-E-3
DOI ID：10.34385/proc.47.C2L-E-3, CiNii Articles ID：230000009176 - Common noise-induced synchronization of relaxation oscillators
Tsubasa Kawai; Takuya Kurihara; Yutaka Shimada; Kantaro Fujiwara; Kenya Jin'no; Tohru Ikeguchi
IFAC-PapersOnLine, Volume：48, Number：18, First page：233, Last page：238, 2015, [Reviewed]
© 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Common noise-induced synchronization is widely observed in various nonlinear oscillators. We used the relaxation oscillators that have two internal states changed by their threshold values. We investigated how the relaxation oscillators synchronize by common 1/fα noise. As a result, we found that characteristics of the noise-induced synchronization of these relaxation systems depend on how the common 1/fα noise is applied, namely to the internal state or to the threshold value.
Elsevier BV, Scientific journal
DOI：https://doi.org/10.1016/j.ifacol.2015.11.042
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84992507366&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84992507366&origin=inward
DOI ID：10.1016/j.ifacol.2015.11.042, eISSN：2405-8963, SCOPUS ID：84992507366 - Performance analysis of adaptive tabu search for quadratic assignment problems
Akio Watanabe; Yutaka Shimada; Kantaro Fujiwara; Takaomi Shigehara; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：46, First page：241, Last page：244, 2014, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.46.B1L-C2
DOI ID：10.34385/proc.46.B1L-C2, CiNii Articles ID：230000008737 - Analysis on temporal effects in time-varying social networks
Yutaka Shimada; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：46, First page：541, Last page：544, 2014, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.46.C2L-D5
DOI ID：10.34385/proc.46.C2L-D5, CiNii Articles ID：230000008797 - Phase synchronization in chaotic oscillators induced by common noise
Tsubasa Kawai; Yutaka Shimada; Kantaro Fujiwara; Kenya Jin'no; Tohru Ikeguchi
Proceedings of International Symposium on the Nonlinear Theory and its Applications, Number：46, First page：621, Last page：624, 2014, [Reviewed]
The Institute of Electronics, Information and Communication Engineers, English, International conference proceedings
DOI：https://doi.org/10.34385/proc.46.C3L-D4
DOI ID：10.34385/proc.46.C3L-D4, CiNii Articles ID：230000008807 - Detecting stretch-and-fold mechanism in chaotic dynamics
Yutaka Shimada; Taiji Yamada; Tohru Ikeguchi
International Journal of Bifurcation and Chaos, Volume：22, Number：11, First page：1230038, Nov. 2012, [Reviewed], [Lead]
We propose a simple but effective visualization method for detecting the stretch-and-fold mechanism in chaotic dynamical systems. In the proposed method, we first place a hypersphere that is centered at a point on the trajectory of an attractor produced from the chaotic dynamical system. Second, we uniformly arrange points on the surface of the hypersphere. Third, we evolve the dynamics and observe the temporal evolution of the center point and the points on the surface. We then calculate the temporal evolution of the distances between the center point and the points on the surface. Finally, we express them using multiple colors and draw the colors representing the distances at the initial position on the hypersphere. Then, we observe the temporal changes of these colors generated by the temporal evolution of the distances. Application of the proposed method to chaotic dynamics results in the appearance of stripe patterns on the surface of the hypersphere over time. The results indicate that we can detect the stretch-and-fold mechanism, or the horse-shoe structure embedded in chaotic dynamics. We also discussed the reason for the generation of the stripe pattern under the framework of the proposed method. © 2012 World Scientific Publishing Company.
WORLD SCIENTIFIC PUBL CO PTE LTD, English, Scientific journal
DOI：https://doi.org/10.1142/S0218127412300388
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84871030677&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84871030677&origin=inward
DOI ID：10.1142/S0218127412300388, ISSN：0218-1274, SCOPUS ID：84871030677, Web of Science ID：WOS:000312456300003 - From networks to time series
Yutaka Shimada; Tohru Ikeguchi; Takaomi Shigehara
Physical Review Letters, Volume：109, Number：15, First page：158701, Oct. 2012, [Reviewed], [Lead]
In this Letter, we propose a framework to transform a complex network to a time series. The transformation from complex networks to time series is realized by the classical multidimensional scaling. Applying the transformation method to a model proposed by Watts and Strogatz, we show that ring lattices are transformed to periodic time series, small-world networks to noisy periodic time series, and random networks to random time series. We also show that these relationships are analytically held by using the circulant-matrix theory and the perturbation theory of linear operators. The results are generalized to several high-dimensional lattices. © 2012 American Physical Society.
AMER PHYSICAL SOC, English, Scientific journal
DOI：https://doi.org/10.1103/PhysRevLett.109.158701
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84867320265&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84867320265&origin=inward
DOI ID：10.1103/PhysRevLett.109.158701, ISSN：0031-9007, eISSN：1079-7114, SCOPUS ID：84867320265, Web of Science ID：WOS:000309658300025 - Reconstruction of Input Information Using Transformation from Spike Trains to an Instantaneous Mean-Firing-Rate Time Series
KURODA Kaori; SHIMADA Yutaka; SUZUKI Mai; IKEGUCHI Tohru
The IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences (Japanese edition) A, Volume：94, Number：2, First page：64, Last page：72, Feb. 2011, [Reviewed]
本論文では, ニューロンへの入力情報再構成問題に対する新たな手法として, ニューロンから生成されたスパイク列を瞬時平均発火率の時系列に変換する手法を提案する.具体的には, カーネル関数を用いた瞬時平均発火率の推定に基づく手法である.その際, カーネル関数のバンド幅を最適設定するために二つの手法を導入した.第1の手法はShimazakiらによって提案されたカーネルバンド幅最適化法の応用である.第2の手法は, カオス時系列解析において用いられるアトラクタ再構成での時間遅れ値設定法の応用である.ニューロンに対する入力時系列と二つのバンド幅設定法により変換された再構成時系列の比較実験を行った.入力時系列には, 数理モデルにより作成した周期時系列, 準周期時系列, カオス時系列と日本語母音「あ」の発音時系列を用いている.相互相関係数を用いて提案手法の性能を評価した結果, 導入した最適バンド幅の設定法によりカーネル関数のバンド幅を定めることで, ニューロンに対する入力情報を再構成できることが示された.
The Institute of Electronics, Information and Communication Engineers, Japanese
ISSN：0913-5707, CiNii Articles ID：110008440901, CiNii Books ID：AN10013345 - Emergence of fit-get-rich networks from chaotic attractors
Yutaka Shimada; Tohru Ikeguchi
Physics Letters A, Volume：374, Number：31-32, First page：3170, Last page：3176, Jul. 2010, [Reviewed], [Lead]
Connecting dynamical information of the nonlinear dynamical systems to the temporal evolution of complex networks, we analyze nonlinear dynamical systems with complex-network theory. We dynamically construct networks from attractors of nonlinear dynamical systems depending on their dynamical information and thereby we can evaluate the attractors through the evolution processes of constructed networks. As a result, we find that the constructed networks from periodic attractors correspond to the first-mover-advantage phase and those from chaotic attractors correspond to the fit-get-rich phase. We also show that the fit-get-rich property is originated to an essential mechanism for producing chaotic dynamics stretching and folding. (C) 2010 Elsevier B.V. All rights reserved.
Elsevier BV, English, Scientific journal
DOI：https://doi.org/10.1016/j.physleta.2010.05.048
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=77955311218&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=77955311218&origin=inward
DOI ID：10.1016/j.physleta.2010.05.048, ISSN：0375-9601, SCOPUS ID：77955311218, Web of Science ID：WOS:000280452700012 - Transformation from complex networks to time series using classical multidimensional scaling
Yuta Haraguchi; Yutaka Shimada; Tohru Ikeguchi; Kazuyuki Aihara
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Volume：5769 LNCS, Number：PART 2, First page：325, Last page：334, 2009, [Reviewed]
Various complex phenomena exist in the real world. Then, many methods have already been proposed to analyze the complex phenomena. Recently, novel methods have been proposed to analyze the deterministic nonlinear, possibly chaotic, dynamics using the complex network theory [1, 2, 3]. These methods evaluate the chaotic dynamics by transforming an attractor of nonlinear dynamical systems to a network. In this paper, we investigate the opposite direction: we transform complex networks to a time series. To realize the transformation from complex networks to time series, we use the classical multidimensional scaling. To justify the proposed method, we reconstruct networks from the time series and compare the reconstructed network with its original network. We confirm that the time series transformed from the networks by the proposed method completely preserves the adjacency information of the networks. Then, we applied the proposed method to a mathematical model of the small-world network (the WS model). The results show that the regular network in the WS model is transformed to a periodic time series, and the random network in the WS model is transformed to a random time series. The small-world network in the WS model is transformed to a noisy periodic time series. We also applied the proposed method to the real networks - the power grid network and the neural network of C. elegans - which are recognized to have small-world property. The results indicate that these two real networks could be characterized by a hidden property that the WS model cannot reproduce. © 2009 Springer Berlin Heidelberg.
International conference proceedings
DOI：https://doi.org/10.1007/978-3-642-04277-5_33
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=70450183314&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=70450183314&origin=inward
DOI ID：10.1007/978-3-642-04277-5_33, ISSN：0302-9743, eISSN：1611-3349, SCOPUS ID：70450183314 - Analysis of chaotic dynamics using measures of the complex network theory
Yutaka Shimada; Takayuki Kimura; Tohru Ikeguchi
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Volume：5163 LNCS, Number：PART 1, First page：61, Last page：70, 2008, [Reviewed], [Lead]
Complex phenomena are observed in various situations. These complex phenomena are produced from deterministic dynamical systems or stochastic systems. Then, it is an important issue to clarify what is a source of the complex phenomena and to analyze what kind of response will emerge. Then, in this paper, we analyze deterministic chaos from a new aspect. The analysis method is based on the idea that attractors of nonlinear dynamical systems and networks are characterized by a two-dimensional matrix: a recurrence plot and an adjacent matrix. Then, we transformed the attractors to the networks, and evaluated the clustering coefficients and the characteristic path length to the networks. As a result, the networks constructed from the chaotic systems show a small world property. © Springer-Verlag Berlin Heidelberg 2008.
SPRINGER-VERLAG BERLIN, English, International conference proceedings
DOI：https://doi.org/10.1007/978-3-540-87536-9_7
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=58949092347&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=58949092347&origin=inward
DOI ID：10.1007/978-3-540-87536-9_7, ISSN：0302-9743, eISSN：1611-3349, SCOPUS ID：58949092347, Web of Science ID：WOS:000259566200007
- An Analysis on the Relationship Between the Backbone Structure of Word Co-Occurrence Networks and Stylistic Features of Novels
Tazawa Shodai; Shimada Yutaka
IEICE Proceeding Series, Volume：76, First page：194, Last page：197, 21 Sep. 2023
Complex networks observed in the real world contain strongly connected vertex pairs. A set of such vertex pairs and their connections in a network is sometimes called backbone of the network. The disparity filter is one of the methods for extracting these strongly connected vertex pairs from observed networks. We have generated word co-occurrence networks from English novels, where vertices represent words, edges represent co-occurrence relationships of words, and weights of edges correspond to the co-occurrence frequencies. We have investigated backbone structure of word co-occurrence networks extracted by the disparity filter. The results show that the backbones of word co-occurrence networks might contain information about stylistic attributes of the author who wrote the novels from which the word co-occurrence networks were generated.
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.34385/proc.76.a5l-32
DOI ID：10.34385/proc.76.a5l-32, eISSN：2188-5079 - A Network-Based Analysis on Collective Behavior of the Audience in a Concert
Ban Takahiro; Kimura Manami; Nomura Ryota; Shimada Yutaka
IEICE Proceeding Series, Volume：76, First page：190, Last page：193, 21 Sep. 2023
The studies on networks of human interactions have attracted much attention in various fields including social and network sciences, epidemiology, and cognitive psychology. The data on human behavior such as human body motion and proximity relationships between individuals play an important role in these studies. These data are collected mainly in several educational and medical settings, while few data in other situations are so far available. In this paper, we observed body motions of audience members at a concert and investigated collective behavior through a network in which vertices represent audience members and edges reflect similarities between the motions of audience members. The results indicate that differences in performers have a significant effect on the collective behavior of audience members and the local structure of the obtained networks might reflect characteristic behavioral features of audience members.
The Institute of Electronics, Information and Communication Engineers, English
DOI：https://doi.org/10.34385/proc.76.a5l-31
DOI ID：10.34385/proc.76.a5l-31, eISSN：2188-5079 - Detecting causality for marked point processes
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会技術研究報告(Web), Volume：122, Number：436(NLP2022 107-155), 2023
ISSN：2432-6380, J-Global ID：202302273916491727 - Effect of reconstruction dimension on causality detection for spike trains
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2023, 2023
ISSN：1349-144X, J-Global ID：202302251745300379 - A study on prediction of outcomes of future games by network-based ranking for competitive sports
石倉龍海; 島田裕
電子情報通信学会大会講演論文集(CD-ROM), Volume：2023, 2023
ISSN：1349-144X, J-Global ID：202302236716731109 - Analysis on body-motion behavior of audience at a concert
伴崇弘; 木村真実; 野村亮太; 島田裕
電子情報通信学会大会講演論文集(CD-ROM), Volume：2023, 2023
ISSN：1349-144X, J-Global ID：202302227891744507 - On link prediction of temporal networks using graph distances
猪狩大気; 島田裕
電子情報通信学会大会講演論文集(CD-ROM), Volume：2023, 2023
ISSN：1349-144X, J-Global ID：202302232637471366 - An analysis on backbone structure of word co-occurrence networks
田澤将大; 島田裕
電子情報通信学会技術研究報告(Web), Volume：122, Number：436(NLP2022 107-155), 2023
ISSN：2432-6380, J-Global ID：202302241004749307 - Investigation of backbone structure of word co-occurrence networks generated from novels
田澤将大; 島田裕
電子情報通信学会大会講演論文集(CD-ROM), Volume：2023, 2023
ISSN：1349-144X, J-Global ID：202302212824573146 - Emotions and hubs in a network of colexification
福家水月; 松本朋子; 島田裕; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2022, 2022
ISSN：1349-144X, J-Global ID：202202252651320786 - A study on reconstruction parameters for transforming photoplethysmogram into time-delay coordinate system
澤田和弥; SVIRIDOVA Nina; 島田裕; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2022, 2022
ISSN：1349-144X, J-Global ID：202202244769624771 - Detecting causality for spike trains based on reconstructing dynamical systems from inter-spike intervals
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会技術研究報告(Web), Volume：122, Number：145(CCS2022 26-42), 2022
ISSN：2432-6380, J-Global ID：202202241698224564 - On causality detection for neural spike trains
澤田和弥; 島田裕; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2022, 2022
ISSN：1349-144X, J-Global ID：202302217543453624 - Reconstructing dynamical system from marked point processes and its application to real world data
澤田和弥; SVIRIDOVA Nina; SVIRIDOVA Nina; 島田裕; 池口徹; 池口徹
電子情報通信学会技術研究報告(Web), Volume：121, Number：335(NLP2021 69-125), 2022
ISSN：2432-6380, J-Global ID：202202249176915860 - Extraction of Property for Nonlinear Time Series by Changing Density of Recurrence Plots
金丸志生; SVIRIDOVA Nina; 島田裕; 池口徹; 池口徹
電子情報通信学会技術研究報告(Web), Volume：120, Number：330(NLP2020 40-54), 2021
ISSN：2432-6380, J-Global ID：202102211471373624 - Discrimination between Chaotic Time Series and Noisy Quasi-periodic Solutions
金丸志生; SVIRIDOVA Nina; 島田裕; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2021, 2021
ISSN：1349-144X, J-Global ID：202102247560469039 - Relation between Frequency of Words and Language Network Structures
眞岸祈平; 松本朋子; 島田裕; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2021, 2021
ISSN：1349-144X, J-Global ID：202102258990671164 - Influence of Contact Properties to Information Diffusion on Temporal Networks
XU Luyan; 澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2021, 2021
ISSN：1349-144X, J-Global ID：202102279905258883 - Tissue Specific Network Motifs in Gene Regulatory Networks
CHAM Haga; 島田裕; 重原孝臣
電子情報通信学会大会講演論文集(CD-ROM), Volume：2021, 2021
ISSN：1349-144X, J-Global ID：202102287359188065 - On State Space Reconstruction from Marked Point Processes
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2021, 2021
ISSN：1349-144X, J-Global ID：202102288757103356 - Detection of Unobserved Vertices in Network Inference Problems
榊原有貴; 島田裕; 重原孝臣
電子情報通信学会大会講演論文集(CD-ROM), Volume：2021, 2021
ISSN：1349-144X, J-Global ID：202102290913315952 - A study on estimating appropriate parameters of state space reconstruction
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会技術研究報告(Web), Volume：121, Number：307(NLP2021 43-68), 2021
ISSN：2432-6380, J-Global ID：202202234489011812 - Robustness against Noise on Detecting Causality between Spike Trains
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2020, 2020
ISSN：1349-144X, J-Global ID：202002252854183223 - Analysis of language networks for the New Testament
眞岸祈平; 松本朋子; 島田裕; 池口徹
電子情報通信学会技術研究報告(Web), Volume：120, Number：55(NLP2020 11-21), 2020
ISSN：2432-6380, J-Global ID：202002222550837268 - On Investigation of Invariant Characteristics of Deterministic Nonlinear Dynamical Systems and Marked Point Processes
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会技術研究報告(Web), Volume：120, Number：165(NLP2020 22-31), 2020
ISSN：2432-6380, J-Global ID：202002255344893562 - Causality Analysis for Marked Point Process
澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2020, 2020
ISSN：1349-144X, J-Global ID：202102222058712322 - Effects of excitatory/inhibitory neuron ratio on synaptic infomation entropy
宮南風; 島田裕; 藤原寛太郎; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2020, 2020
ISSN：1349-144X, J-Global ID：202102222810635044 - Analysis of Information Diffusion on Temporal Networks
XU Luyan; 澤田和弥; 島田裕; 池口徹; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2020, 2020
ISSN：1349-144X, J-Global ID：202102242472172520 - Impact of the differences in document contents on the structure of language networks
眞岸祈平; 松本朋子; 島田裕; 池口徹
電子情報通信学会大会講演論文集(CD-ROM), Volume：2020, 2020
ISSN：1349-144X, J-Global ID：202102255548947241 - 拡張Visibility Graphを用いた楽曲構造の特徴抽出について
MAO Fujia; 島田裕; 池口徹; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902223141661018 - 非線形力学系理論に基づいたスパイク列間の因果推定
澤田和弥; 島田裕; 池口徹; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902238233867376 - カオスダイナミクスによる擬似乱数にXORを施した場合の性能評価
金丸志生; 島田裕; 藤原寛太郎; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902242162495086 - マーク付点過程データに対する決定論性の調査手法
山本紘平; 島田裕; 池口徹; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902246522627033 - 興奮性/抑制性ニューロン比率がシナプス結合強度とネットワーク構造に与える影響
宮南風; 島田裕; 藤原寛太郎; 池口徹; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902260056869336 - 興奮性/抑制性ニューロン比率が発火率と学習に与える効果
宮南風; 島田裕; 藤原寛太郎; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902263324051887 - 領域閾値リカレンスプロットを用いた非線形時系列解析
金丸志生; 島田裕; 池口徹; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902265048013930 - カオスMIMOシステムにおけるビットの利用法の改良とその性能評価
山崎凌; 島田裕; 池口徹; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902273634387927 - Convergent Cross Mappingによる複雑ネットワーク構造上での因果推定
澤田和弥; 島田裕; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902284473110894 - TRPM2チャネルがインスリン分泌に与える影響の調査
笠原宏太朗; 島田裕; 藤原寛太郎; 池口徹; 池口徹
Volume：2019, 2019
ISSN：1349-144X, J-Global ID：201902280191152341 - 整数ロジスティック写像の応答より生成した乱数列の統計的解析
金丸志生; 島田裕; 島田裕; 藤原寛太郎; 池口徹
Volume：2018, 2018
ISSN：1349-144X, J-Global ID：201802244504912137 - メトロノーム同期実験において出現するカオス応答の解析
中川祐季; 島田裕; 島田裕; 藤原寛太郎; 池口徹
Volume：2018, 2018
ISSN：1349-144X, J-Global ID：201802253730894041 - サロゲートデータ法を用いたカオスMIMOシステムの性能解析
山崎凌; 島田裕; 藤原寛太郎; 池口徹
Volume：2018, 2018
ISSN：1349-144X, J-Global ID：201802264669389014 - 重み付き有向ネットワークの指標を用いた多言語間の比較
多々良真弓美; 島田裕; 藤原寛太郎; 藤原寛太郎; 池口徹; 池口徹
Volume：2018, 2018
ISSN：1349-144X, J-Global ID：201802277604513764 - 高速株式取引データに対する非線形解析
山本紘平; 島田裕; 島田裕; 藤原寛太郎; 池口徹
Volume：2018, 2018
ISSN：1349-144X, J-Global ID：201802278680534151 - 有色ノイズによるカオス写像の共通ノイズ同期現象に関する一検討
栗田いずみ; 島田裕; 藤原寛太郎; 池口徹; 池口徹
Volume：2018, 2018
ISSN：1349-144X, J-Global ID：201802214151378265 - 数理モデルによる膵β細胞のTRPM2チャネル活性の再現
笠原宏太朗; 島田裕; 藤原寛太郎; 池口徹
Volume：2018, 2018
ISSN：1349-144X, J-Global ID：201802268371702930 - AS-1-6 Relations between the method for transforming networks to time series and communities in a network
Shimada Yutaka; Hirata Yoshito; Ikeguchi Tohru; Aihara Kazuyuki
Proceedings of the Society Conference of IEICE, Volume：2013, First page："S, Last page：10"-"S-11", 03 Sep. 2013
The Institute of Electronics, Information and Communication Engineers, English
CiNii Articles ID：110009737291, CiNii Books ID：AN10489017
- A Hyperheuristic Method Using The Nonlinear Dynamical Theory for Next-Generation Delivery Planning
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), 01 Apr. 2023 - 31 Mar. 2026
Nippon Institute of Technology
Grant amount(Total)：4810000, Direct funding：3700000, Indirect funding：1110000
Grant number：23K04274 - 非線形力学系理論に基づく人間行動データ解析基盤の構築
01 Apr. 2021 - 31 Mar. 2026
Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
Grant number：21H03508 - メタ文法規則の導出による数理言語学基盤の構築
01 Apr. 2021 - 31 Mar. 2025
Grant amount(Total)：17160000, Direct funding：13200000, Indirect funding：3960000
Grant number：21H03514 - Reconstructing common inputs that evoke audience's collective behaviours
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), 01 Apr. 2021 - 31 Mar. 2025
Waseda University
Grant amount(Total)：4160000, Direct funding：3200000, Indirect funding：960000
Grant number：21K12093 - Fundamentals and developments of brainmorphic computing hardware
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), 01 Apr. 2020 - 31 Mar. 2025
Tohoku University
Grant amount(Total)：44590000, Direct funding：34300000, Indirect funding：10290000
Grant number：20H00596 - Analysis on high-resolution spatiotemporal patterns by a graph distance and its application to information diffusion analysis
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Early-Career Scientists, 01 Apr. 2018 - 31 Mar. 2021
Shimada Yutaka, Saitama University
Grant amount(Total)：3770000, Direct funding：2900000, Indirect funding：870000
Spatio-temporal changes in the relationship between any two individuals in a population can be described by temporal networks, which is a series of graphs consisting of a set of nodes and links. In this study, incorporating a notion of inter-netowork distance, we proposed a new method for analyzing temporal networks and demonstrated its effectiveness in the prediction of temporal networks and structural analyses of various types of networks. We also investigated information diffusion on temporal networks and discuss the applicability of our method to its prediction and control.
Grant number：18K18125 - Network Dynamical System Theory and its Application to Big Data analysis
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), 01 Apr. 2017 - 31 Mar. 2020
Ikeguchi Tohru, Tokyo University of Science
Grant amount(Total)：4550000, Direct funding：3500000, Indirect funding：1050000
The purpose of this study is to consturct a new theory of network dynamical systems with new distance between networks which is appropriate to characterize the network. In addition, we apply the theory developed here to real-world network analysis. The concrete results are as follows. (1) Using a quantitative measure of distance between networks based on spectral graph theory, we estabish the foundation of network dynamical system theory. (2)We also have developed several theories on the network theory. Furthermore, we have applied the proposed theory to the analysis of spatio-temporal network data in the real world with high resolution.
Grant number：17K00348 - Person flow estimation by the analysis of bus drive-recorder videos for bus operation planning
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), 01 Apr. 2017 - 31 Mar. 2020
Taniguchi Yukinobu, Tokyo University of Science
Grant amount(Total)：4550000, Direct funding：3500000, Indirect funding：1050000
A bus transportation system provides social and economic advantages and plays a key role in our daily lives. This study aims at utilizing videos recorded by cameras installed in buses to improve and optimize bus services, where the required basic and important information is bus passenger flow. We mainly explored a method for automatically estimating the boarding section from camera images. The accuracy was improved by leveraging the bus-specific properties or constraints. With the collaboration with a bus company, we evaluated our methods using the drive-recorder videos and showed that the proposed method can achieve almost the same accuracy as that obtained via human visual inspection.
Grant number：17K06608 - Towards Math-Agro Science -Mathematical Analysis and Control on Alternate Bearing and Synchronization-
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), 10 Jul. 2015 - 31 Mar. 2019
IKEGUCHI TOHRU, Tokyo University of Science
Grant amount(Total)：4680000, Direct funding：3600000, Indirect funding：1080000
The purpose of this research project is to consruct a basic framework of "math-agro science," which treats several unresolved issues in the field of agriculture by using methodologies of mathematical science. In particular, in this project, we resolve an issue of synchronization in plants, which is called "alternate bearing." The alternate bearing is a synchronization of fruit bearing in which the volumes of product increases or decreases every two years.
In this project, this phenomenon is modeled by applying the theory of common noise synchronization phenomenon of nonlinear oscillators.
The results clearly show that the proposed models can reproduce the alternate bearing and synchronization, which indecates that using the proposed framework in this project, we can analyze and control the alternate bearing and synchronization.
Grant number：15KT0112 - Analysis on human interaction by Nonlinear time series analysis toward the prediction of infectious disease
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), 01 Apr. 2016 - 31 Mar. 2018
Shimada Yutaka, Tokyo University of Science
Grant amount(Total)：2470000, Direct funding：1900000, Indirect funding：570000
We proposed a method for analyzing human interaction data by using a nonlinear time series analysis, where we incorporated the graph distance for complex networks into the conventional nonlinear time series analysis. Using this method, we elucidated the underlying properties of these data. We also applied our method to the prediction of infectious disease, and showed its predictability.
Grant number：16K16126 - Analysis method for time-evolving networks and its application to high resolution data analysis
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity Start-up, Grant-in-Aid for Research Activity Start-up, 29 Aug. 2014 - 31 Mar. 2016
Shimada Yutaka, Tokyo University of Science
Grant amount(Total)：2600000, Direct funding：2000000, Indirect funding：600000
The internet, neuronal networks, sending/receiving relationship of e-mails, and human contacts are described and analyzed as complex networks. They usually evolve with time, changing their connections between vertices, and it is highly important to analyze their underlying spatio-temporal properties in observed data.
We have focused on networks whose structures vary with time, and proposed a distance that can appropriately evaluate the amount of change from the perspective of spatio-temporal structures of networks. We applied our method to mathematical models and real network data, and showed that the proposed distance can detect the properties of networks that cannot be detected by the conventional distances.
Grant number：26880020 - 非線形時系列解析論と複雑ネットワーク論を融合した新しい複雑現象の解析法
2010 - 2011
Grant amount(Total)：1400000, Direct funding：1400000
Grant number：10J08148