著者
中村 直俊
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.31, no.3, pp.28-33, 2021-09-22 (Released:2021-12-26)
参考文献数
19
著者
吉田 善章
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.29, no.3, pp.6-13, 2019-09-25 (Released:2019-12-26)
参考文献数
12

The creation of macroscopic hierarchy (such as fluids or plasmas) is studied in the context of noncanonical Hamiltonian systems. We study the origin of noncanonicality in two perspectives; (1) the reductions from canonical systems, (2) the Lie-Poisson algebras and their deformations, and show how the dynamics of macro-systems can be different from those of microscopic canonical systems.
著者
矢島 美寛
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.11, no.4, pp.281-294, 2001-12-14 (Released:2017-04-08)
参考文献数
53

This paper provides a survey of long memory models and their applications in economic and financial time series. Section 2 describes the definition of long memory models, particularly two popular models, ARFIMA and FGN. Section 3 describes unit roots tests and cointegration, two major topics of the recent decades in theoretical and applied econometrics. Section 4 discusses a generalization of unit roots tests and cointegration to long memory models. Section 5 describes ARCH models and SV models which have been paid much attention to analyze volatility in actual financial data. Section 6 considers a generalization of these volatility models to those with long memory properties. Finally Section 7 considers some problems to be solved in future.
著者
宮武 勇登
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.28, no.3, pp.15-22, 2018-09-26 (Released:2018-12-26)
参考文献数
35

Continuous stage Runge-Kutta (CSRK) methods, which were introduced around 2010, are a framework of iterative numerical methods for solving ordinary differential equations. It turned out that some CSRK methods preserve some underlying geometric structures of differential equations, such as symplecticity or energy-preservation of Hamiltonian systems. This paper reviews CSRK methods and their recent developments with emphasis on their structure-preservation properties.
著者
川越 大輔
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.30, no.4, pp.16-23, 2020-12-22 (Released:2021-03-31)
参考文献数
18

Optical tomography is a new medical imaging technique which makes use of near infrared light, and it is mathematically modeled as an inverse problem to determine a coefficient in the stationary transport equation from boundary measurements. In this paper, we show two results on regularity of solutions to the direct problem of the stationary transport equation. The first result is to describe discontinuity of the solution which arises from discontinuous points of the incoming boundary data, and we show the exponential decay of a jump of the solution on a discontinuous point. The decay gives an idea for solving the inverse problem. The second one is to give a W1, p estimate of the solution to the direct problem in two-dimensional cases. Here, the exponent p has an upper bound pm, which is a real number depending only on the shape of the domain. This estimate is crucial when we solve the direct problem numerically with the discrete-ordinate discon-tinuous Galerkin method.
著者
今 隆助
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.25, no.3, pp.112-119, 2015-09-25 (Released:2017-04-08)

Periodical cicadas are known for their perfectly synchronized prime number emergences of either 13 or 17 year period. One of th eexplanations for the prime periodicity is that the prime periods are selected to prevent cicadas from resonating with predators with submultiple periods. This paper considers this hypothesis by investigating a population model for periodical predator and prey. The study shows that if the periods of the two periodical species are not coprime, then the predator cannot resist the invasion of the prey. On the other hand, if the periods are coprime, then the predator can eradicate the prey. These results suggest that prime number periods are disadvantageous under periodic predation pressure. Numerical investigations illustrate a non-coprime case where both populations coexist.
著者
桂 利行
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.14, no.1, pp.71-74, 2004-03-25 (Released:2017-04-08)
参考文献数
3
著者
松葉 育雄
出版者
一般社団法人 日本応用数理学会
雑誌
応用数理 (ISSN:24321982)
巻号頁・発行日
vol.5, no.3, pp.192-208, 1995-09-18 (Released:2017-04-08)
参考文献数
22
被引用文献数
1

不規則に変動する成分をランダムノイズとする統計的手法に従う時系列データ処理法に対し,カオスの発見以来,確率的成分を有しない非線形ダイナミクスが内在するメカニズムのみから不規則な様相を見せることが明らかにされ,不規則データのモデル化に関して従来と異なるアプローチが要求されるようになってきた.実際,カオティックな時系列データに対して統計モデルよりも非線形なモデルを基礎にした決定論的な方式が優れていることが示されるようになってきた.本稿では,カオスモデルだけではなく実際的な例を通してニューラルネットワークを予測の道具に用いた非線形予測の可能性を議論する.