論文

公開件数: 28 件
No. 掲載種別 単著・共著区分 タイトル 著者 誌名 出版者 巻号頁 出版日 ISSN DOI URL 概要
1 研究論文(学術雑誌)
共著
Sudden spreading of infections in an epidemic model with a finite seed fraction
Takehisa Hasegawa, Koji Nemoto
The European Physical Journal B

91
2018/03/29

10.1140/epjb/e2018-80343-3


2
共著
Efficiency of prompt quarantine measures on a susceptible-infected-removed model in networks
Hasegawa Takehisa, Nemoto Koji
Physical Review E
American Physical Society (APS)
96/ 2
2017/08/11
2470-0045
10.1103/PhysRevE.96.022311
URL

3
共著
Local cluster-size statistics in the critical phase of bond percolation on the Cayley tree
Tomoaki Nogawa, Takehisa Hasegawa, Koji Nemoto
Journal of Statistical Mechanics: Theory and Experiment


2016/05/11

10.1088/1742-5468/2016/05/053202


4
共著
Outbreaks in susceptible-infected-removed epidemics with multiple seeds
Hasegawa Takehisa, Nemoto Koji
Physical Review E
American Physical Society (APS)
93/ 3
2016/03/31
2470-0045
10.1103/PhysRevE.93.032324
URL
We study a susceptible-infected-removed (SIR) model with multiple seeds on a regular random graph. Many researchers have studied the epidemic threshold of epidemic models above which a global outbreak can occur, starting from an infinitesimal fraction of seeds. However, there have been few studies of epidemic models with finite fractions of seeds. The aim of this paper is to clarify what happens in phase transitions in such cases. The SIR model in networks exhibits two percolation transitions. We derive the percolation transition points for the SIR model with multiple seeds to show that as the infection rate increases epidemic clusters generated from each seed percolate before a single seed can induce a global outbreak.
5
共著
Advantage or disadvantage of migration in a prey-predator system
Kazunori Sato, Takehisa Hasegawa, Satoru Morita, Jin Yoshimura, Kei-ichi Tainaka
Far East Journal of Applied Mathematics


2015




6
共著
Discontinuous transition of a multistage independent cascade model on networks
Takehisa Hasegawa, Koji Nemoto
Journal of Statistical Mechanics: Theory and Experiment


2014/11/14

10.1088/1742-5468/2014/11/P11024


7
共著
Critical Phase in Complex Networks: a Numerical Study
Takehisa Hasegawa, Tomoaki Nogawa, Koji Nemoto
Discontinuity, Nonlinearity, and Complexity


2014/10/01

10.5890/DNC.2014.09.008


8
共著
Suppressing epidemics on networks by exploiting observer nodes
Taro Takaguchi, Takehisa Hasegawa, Yuichi Yoshida
Physical Review E


2014/07/11

10.1103/PhysRevE.90.012807


9
共著
Transition-type change between an inverted Berezinskii-Kosterlitz-Thouless transition and an abrupt transition in bond percolation on a random hierarchical small-world network
Tomoaki Nogawa, Takehisa Hasegawa
Physical Review E


2014/04/07

10.1103/PhysRevE.89.042803


10
共著
Hierarchical scale-free network is fragile against random failure
Hasegawa Takehisa, Nemoto Koji
Physical Review E
American Physical Society
88/ 6, 62807-1-062807-5
2013/12/06
1539-3755
10.1103/PhysRevE.88.062807
URL
We investigate site percolation in a hierarchical scale-free network known as the Dorogovtsev-Goltsev-Mendes network. We use the generating function method to show that the percolation threshold is 1, i.e., the system is not in the percolating phase when the occupation probability is less than 1. The present result is contrasted to bond percolation in the same network of which the percolation threshold is zero. We also show that the percolation threshold of intentional attacks is 1. Our results suggest that this hierarchical scale-free network is very fragile against both random failure and intentional attacks. Such a structural defect is common in many hierarchical network models.
11
共著
Profile and scaling of the fractal exponent of percolations in complex networks
Takehisa Hasegawa, Tomoaki Nogawa, Koji Nemoto
EPL


2013/11/06

10.1209/0295-5075/104/16006


12
共著
Observability transitions in correlated networks
Takehisa Hasegawa, Taro Takaguchi, Naoki Masuda
Physical Review E


2013/10/14

10.1103/PhysRevE.88.042809


13
共著
Absence of the non-percolating phase for percolation on the non-planar Hanoi network
Takehisa Hasegawa, Tomoaki Nogawa
Physical Review E


2013/03/18

10.1103/PhysRevE.87.032810


14
共著
Criticality governed by the stable renormalization fixed point of the Ising model in the hierarchical small-world network
Nogawa Tomoaki, Hasegawa Takehisa, Nemoto Koji
Physical Review E
American Physical Society
86/ 3
2012/09
1539-3755
10.1103/PhysRevE.86.030102
URL
We study the Ising model in a hierarchical small-world network by renormalization group analysis and find a phase transition between an ordered phase and a critical phase, which is driven by the coupling strength of the shortcut edges. Unlike ordinary phase transitions, which are related to unstable renormalization fixed points (FPs), the singularity in the ordered phase of the present model is governed by the FP that coincides with the stable FP of the ordered phase. The weak stability of the FP yields peculiar criticalities, including logarithmic behavior. On the other hand, the critical phase is related to a nontrivial FP, which depends on the coupling strength and is continuously connected to the ordered FP at the transition point. We show that this continuity indicates the existence of a finite correlation-length-like quantity inside the critical phase, which diverges upon approaching the transition point.
15
共著
Robustness of correlated networks against propagating attacks
Takehisa Hasegawa, Keita Konno, Koji Nemoto
The European Physical Journal B - Condensed Matter And Complex Systems


2012/07/30

10.1140/epjb/e2012-30290-0


16
共著
Generalized Scaling Theory for Critical Phenomena Including Essential Singularities and Infinite Dimensionality
Nogawa Tomoaki, Hasegawa Takehisa, Nemoto Koji
Physical Review Letters
American Physical Society
108/ 25
2012/06/22
0031-9007
10.1103/PhysRevLett.108.255703
URL
We propose a generic scaling theory for critical phenomena that includes power-law and essential singularities in finite and infinite dimensional systems. In addition, we clarify its validity by analyzing the Potts model in a simple hierarchical network, where a saddle-node bifurcation of the renormalization-group fixed point governs the essential singularity.
17
共著
Phase transition without global ordering in a hierarchical scale-free network
Hasegawa Takehisa, Sato Masataka, Nemoto Koji
Physical Review E
American Physical Society
85/ 1
2012/01
1539-3755
10.1103/PhysRevE.85.017101
URL
We study the site-bond percolation on a hierarchical scale-free network, namely, the decorated (2,2)-flower, by using the renormalization group technique. The phase diagram essentially depends on the fraction of occupied sites. Surprisingly, when each site is unoccupied even with a small probability, the system permits neither the percolating phase nor the nonpercolating phase, but rather only critical phases. Although the order parameter always remains zero, a transition still exists between the critical phases that is characterized by the value of the fractal exponent, which measures the degree of criticality; the system changes from one critical state to another with the jump of the fractal exponent at the transition point. The phase boundary depends on the fraction of occupied sites. When the fraction of unoccupied sites exceeds a certain value, the transition line between the critical phases disappears, and a unique critical phase remains.
18
単著
An Introduction to Complex Networks
HASEGAWA Takehisa
Interdisciplinary Information Sciences
The Editorial Committee of the Interdisciplinary Information Sciences
17/ 3, 175-195
2011
1340-9050
10.4036/iis.2011.175
URL
GSIS SELECTED LECTURES: Exploring Collaborative Mathematics
19
共著
Robustness of networks against propagating attacks under vaccination strategies
Takehisa Hasegawa, Naoki Masuda
Journal of Statistical Mechanics: Theory and Experiment


2011/09/20

10.1088/1742-5468/2011/09/P09014


20
共著
Numerical study of a three-state host-parasite system on the square lattice
Takehisa Hasegawa, Norio Konno, Naoki Masuda
Physical Review E


2011/04/06

10.1103/PhysRevE.83.046102


21
共著
Generating-function approach for bond percolations in hierarchical networks
Takehisa Hasegawa, Masataka Sato, Koji Nemoto
Physical Review E


2010/10/01

10.1103/PhysRevE.82.046101


22
共著
Critical phase of bond percolation on growing networks
Hasegawa Takehisa, Nemoto Koji
Physical Review E
American Physical Society
81/ 5
2010/05
1539-3755
10.1103/PhysRevE.81.051105
URL
The critical phase of bond percolation on the random growing tree is examined. It is shown that the root cluster grows with the system size N as Nψ and the mean number of clusters with size s per node follows a power function ns ∝ s(-τ) in the whole range of open bond probability p. The exponent τ and the fractal exponent ψ are also derived as a function of p and the degree exponent γ and are found to satisfy the scaling relation τ=1 + ψ^[-1]. Numerical results with several network sizes are quite well fitted by a finite-size scaling for a wide range of p and γ, which gives a clear evidence for the existence of a critical phase.
23
共著
Reply to the comment on 'Monte Carlo simulation study of the two-stage percolation transition in enhanced binary trees'
Tomoaki Nogawa, Takehisa Hasegawa
Journal of Physics A: Mathematical and Theoretical


2009/11/04

10.1088/1751-8113/42/47/478002


24
共著
Ferromagnetic Ising spin systems on the growing random tree
Hasegawa Takehisa, Nemoto Koji
Physical Review E
American Physical Society
80/ 2
2009/08
1539-3755
10.1103/PhysRevE.80.026126
URL
We analyze the ferromagnetic Ising model on a scale-free tree; the growing random tree model with the linear attachment kernel A_k=k+α. We derive an estimate of the divergent temperature T_s below which the zero-field susceptibility of the system diverges. Our result shows that T_s is related to α as tanh(J/T_s)=α/[2(α+1)], where J is the ferromagnetic interaction. An analysis of exactly solvable limit for the model and numerical calculation supports the validity of this estimate.
25
共著
Monte-Carlo simulation study of the two-stage percolation transition in enhanced binary tree
Tomoaki Nogawa, Takehisa Hasegawa
Journal of Physics A: Mathematical and Theoretical


2009/03/16

10.1088/1751-8113/42/14/145001


26
共著
Susceptibility of the Ising model on the scale free network with a Cayley tree-like structure
Takehisa Hasegawa, Koji Nemoto
Physica A: Statistical mechanics and its applications


2007/10/22

10.1016/j.physa.2007.10.041


27
共著
Ising model on the scale-free network with a Cayley-tree-like structure
Takehisa Hasegawa, Koji Nemoto
Physical Review E


2007/02/21

10.1103/PhysRevE.75.026105


28
共著
Real Space Renormalization Group Analysis with the Replica Method for the Two Dimensional Ising Edwards–Anderson Model
Hasegawa Takehisa, Nemoto Koji
Journal of the Physical Society of Japan
THE PHYSICAL SOCIETY OF JAPAN
75/ 7
2006/06/26
0031-9015
10.1143/JPSJ.75.074701
URL
We apply the real space renormalization group (RG) to the replica Hamiltonian of the two dimensional Ising Edwards–Anderson model to discuss the existence of the spin glass (SG) phase. We derive the RG equations under the replica symmetric (RS) ansatz and the resulting flow diagram indicates the existence of the SG phase. The critical exponent for the SG transition has a plausible value while that of the multicritical point (MCP) is a complex number. We consider that this failure at the MCP is due to not taking the RS breaking into account. Indeed we find that the RS breaking parameter is relevant both at the SG critical point and the MCP, indicating the nontriviality of the SG phase of this model.