茨城大学
理学部
理学科(数学・情報数理コース)

准教授

長谷川 雄央

ハセガワ タケヒサ
HASEGAWA TAKEHISA

論文

  1. 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
  2. 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 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.
  3. 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
  4. Discontinuous transition of a multistage independent cascade model on networks Takehisa Hasegawa, Koji Nemoto Journal of Statistical Mechanics: Theory and Experiment 2014/11/14
  5. Critical Phase in Complex Networks: a Numerical Study Takehisa Hasegawa, Tomoaki Nogawa, Koji Nemoto Discontinuity, Nonlinearity, and Complexity 2014/10/01

研究発表

  1. 口頭発表(一般) 階層スモールワールドネットワーク上の確率過程におけるロバストな臨界性 日本物理学会2016年秋季大会 2016/09
  2. 口頭発表(一般) 複数の感染源が引き起こす感染症の爆発的拡がり 日本物理学会2016年秋季大会 2016/09
  3. 口頭発表(一般) ネットワーク上の感染症における隔離対策の効果 日本物理学会2016年秋季大会 2016/09
  4. 口頭発表(一般) Outbreaks in the SIR epidemics with multiple seeds - a statistical physics approach The 2016 (26th) annual meeting of the Japanese Society for Mathematical Biology (JSMB2016) 2016/09
  5. 口頭発表(一般) 複数の感染源を持つSIRモデルが起こすパーコレーション転移 日本物理学会2015年秋季大会 2015/09