JaLCDOI 10.18926/fest/11610
FullText URL 001_047_053.pdf
Author Sasaki, Toru| Ishikawa, Hirofumi| Kajiwara, Tsuyoshi| Watanabe, Masaji|
Abstract We treat the problem of water pollution by the method of a mathematical model. We illustrate the method of analysis with Kojima Lake. We analyze in-flow and out-flow of the lake, compute numerical solutions of the governing equations of the water flow and the pollutant. The simulation leads to the conclusion concerning the figure of Kojima Lake.
Keywords Kojima lake Water analysis Finite element method
Publication Title 岡山大学環境理工学部研究報告
Published Date 1996-03
Volume volume1
Issue issue1
Start Page 47
End Page 53
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313787
JaLCDOI 10.18926/fest/11560
FullText URL 003_031_036.pdf
Author Sasaki, Toru| Kajiwara, Tsuyoshi| Ishikawa, Hirofumi|
Abstract We have computed the phase of spreading contaminations in Kojima Lake by using the upwind-type finite element method. We have treated the two cases: the pollutant flows from the Sasagase river and from the Kurashiki River. We see that the upwind-type finite element method is effective in both cases, when the diffusion constant is quite small.
Keywords Upwind-type Finite element method Kojima Lake
Publication Title 岡山大学環境理工学部研究報告
Published Date 1998-01-14
Volume volume3
Issue issue1
Start Page 31
End Page 36
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313715
JaLCDOI 10.18926/fest/11553
Title Alternative Mathematical analysis of pathogenesis of viral hepatitis.
FullText URL 005_007_011.pdf
Author Sasaki, Toru| Kajiwara, Tsuyoshi|
Abstract Simple mathematical models are considered to explain the pathogenesis of viral hepatitis. Dynamics of populations of liver cells and two virus strains are analyzed qualitatively. This analysis suggests the possibility that the viral mutation causes the hepatitis from the state of carrier.
Keywords hepatitis mathematical model mutation
Publication Title 岡山大学環境理工学部研究報告
Published Date 2000-02-29
Volume volume5
Issue issue1
Start Page 7
End Page 11
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313400
JaLCDOI 10.18926/fest/11555
Title Alternative Simulations of Heel Impact by Viscoelastic Models
FullText URL 005_013_021.pdf
Author Kokubo, Masahito| Sasaki, Toru|
Abstract The purpose of this study is to make some body models with viscoelastic model, to simulate the heel impact and to obtain the ground reaction force. In this paper, we build up body models of linear viscoelastic elements and mass elements to simulate heel impact. Here we consider the systems of linear differential equations numerically for the preparation of mathematical analysis in future. The simplest model with two mass elements is hardly able to simulate the heel impact if the rate of mass of elements is realistic. The models with more elements are suitable to simulate for actual rate of weight of body segments. The model with three mass elements makes it possible to guess the force to each body segment.
Keywords Running Heel Impact Viscoelastic Model Biomechanics
Publication Title 岡山大学環境理工学部研究報告
Published Date 2000-02-29
Volume volume5
Issue issue1
Start Page 13
End Page 21
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313531
JaLCDOI 10.18926/fest/11557
Title Alternative Mathematical analysis of virus infectious diseases by ordinary differential equations
FullText URL 005_023_030.pdf
Author Sasaki, Toru| Kajiwara, Tsuyoshi|
Abstract Some mathematical models describing interaction of virus and cells in vivo are reviewed. Similar models using systems of ordinary differential equations can be used for the analysis of dynamics of virus and cells for different kinds of virus. Models for human immunodeficiency virus, hepatitis C virus and hepatitis B virus are treated here. Although models are similar, different approximations can reduce the systems to the explicitly solvable forms. The solutions obtained here can be used to estimate biological parameters.
Keywords Virus Mathematica models HIV HCV HBV
Publication Title 岡山大学環境理工学部研究報告
Published Date 2000-02-29
Volume volume5
Issue issue1
Start Page 23
End Page 30
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313498
JaLCDOI 10.18926/fest/11527
Title Alternative Random Bit Strings and Antigenic Diversity ― Simulations
FullText URL 006_035_039.pdf
Author Sasaki, Toru|
Abstract Transition of random bit strings is simulated by using pseudorandom numbers. Bit strings are considered as RNA of HIV virus here. Transition of random bit strings represents that of antigenic deversity.
Keywords random bit string simulation of errors in RNA transcription antigenic diversity
Publication Title 岡山大学環境理工学部研究報告
Published Date 2001-02-28
Volume volume6
Issue issue1
Start Page 35
End Page 39
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313453
JaLCDOI 10.18926/fest/11515
Title Alternative Stability analysis of mathematical models of infectious disease
FullText URL 007_017_021.pdf
Author Murase, Akiko| Sasaki, Toru| Kajiwara, Tsuyoshi|
Abstract Dynamics of infectious disease in vivo is described by coupled differential equations. Stability analysis of the complicated systems is difficult without computer calculation, while stability analysis is, in general, important to investigate qualitative behaviour of models. Liu analyzes stability of systems describing HIV dynamics in vivo with a symbolic calculation software. The same method is used for stability analysis of a mathematical model of malaria.
Keywords mathematical model infectious disease dynamics in vivo stability analysis symbolic calculation
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 17
End Page 21
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313783
JaLCDOI 10.18926/fest/11483
Title Alternative On Persistence in Dynamical Systems (Review)
FullText URL 010_013_021.pdf
Author Sasaki, Toru| Kajiwara, Tsuyoshi|
Abstract Some important results on persistence are reviewed. These results concern the behavior of the orbits approaching the boundary. The orbits restrict the flow on the boundary, if one of them approaches more than one invariant set. A typical example is a model for cyclic competition, where the heteroclinic cycle can be the ω-limit set. Thus the persistence can be reduced to some conditions on the boundary flow.
Keywords persistence ordinary differential equation dynamical system
Publication Title 岡山大学環境理工学部研究報告
Published Date 2005-02-28
Volume volume10
Issue issue1
Start Page 13
End Page 21
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313932
JaLCDOI 10.18926/fest/11481
FullText URL 010_009_011.pdf
Author Kajiwara, Tsuyoshi| Sasaki, Toru|
Abstract An elementary proof of permanence for a simple mathematical model proposed by Nowak and Bangham. In many papers, permanence property is proved by theorems established by the general theory of dynamical system. In this paper, we present an elementary proof only using differential inequalities and the theory of linear differential equations with constant coefficients.
Keywords Permanence dynamical system pathogen
Publication Title 岡山大学環境理工学部研究報告
Published Date 2005-02-28
Volume volume10
Issue issue1
Start Page 9
End Page 11
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313596