start-ver=1.4 cd-journal=joma no-vol=1707 cd-vols= no-issue= article-no= start-page=050017 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=2016 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Numerical study on anaerobic digestion of fruit and vegetable waste: Biogas generation en-subtitle= kn-subtitle= en-abstract= kn-abstract= The study provides experimental results and numerical results concerning anaerobic digestion of fruit and vegetable waste. Experiments were carried out by using batch floating drum type digester without mixing and temperature setting. The retention time was 30 days. Numerical results based on Monod type model with influence of temperature is introduced. Initial value problems were analyzed numerically, while kinetic parameters were analyzed by using trial error methods. The numerical results for the first five days seems appropriate in comparison with the experimental outcomes. However, numerical results shows that the model is inappropriate for 30 days of fermentation. This leads to the conclusion that Monod type model is not suitable for describe the mixture degradation of fruit and vegetable waste and horse dung. en-copyright= kn-copyright= en-aut-name=WardhaniPuteri Kusuma en-aut-sei=Wardhani en-aut-mei=Puteri Kusuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Environmental and Life Science, Okayama University kn-affil= en-keyword=Anaerobic digestion kn-keyword=Anaerobic digestion en-keyword=monod model kn-keyword=monod model en-keyword=numerical simulation kn-keyword=numerical simulation END start-ver=1.4 cd-journal=joma no-vol=1707 cd-vols= no-issue= article-no= start-page=050013 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2016 dt-pub=2016 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Mathematical Formulation and Numerical Simulation of Bird Flu Infection Process within a Poultry Farm en-subtitle= kn-subtitle= en-abstract= kn-abstract= Bird flu infection processes within a poultry farm are formulated mathematically. A spatial effect is taken into account for the virus concentration with a diffusive term. An infection process is represented in terms of a traveling wave solutions. For a small removal rate, a singular perturbation analysis lead to existence of traveling wave solutions, that correspond to progressive infection in one direction. en-copyright= kn-copyright= en-aut-name=PutriArrival Rince en-aut-sei=Putri en-aut-mei=Arrival Rince kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NovaTertia Delia en-aut-sei=Nova en-aut-mei=Tertia Delia kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Graduate School Environmental and Life Science, Okayama University kn-affil= affil-num=2 en-affil=Andalas University kn-affil= affil-num=3 en-affil=Graduate School Environmental and Life Science, Okayama University kn-affil= en-keyword=bird flu kn-keyword=bird flu en-keyword=spatial effect kn-keyword=spatial effect en-keyword=traveling wave solutions kn-keyword=traveling wave solutions en-keyword=singular perturbation kn-keyword=singular perturbation END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue=1 article-no= start-page=57 end-page=62 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=200803 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Numerical Study of Effects of Tsunami Wave Generated on Nankai Trough en-subtitle= kn-subtitle= en-abstract= kn-abstract=Numerical techniques to simulate tsunami waves are described, and numerical results are introduced. A finite difference method is applied to shallow water equations to analize the propagation of tsunami wave. Numerical results to simulate a tsunami wave generated on the Nankai Trough are introduced. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=LiuYing kn-aut-sei=Liu kn-aut-mei=Ying aut-affil-num=1 ORCID= en-aut-name=SumidaShinya en-aut-sei=Sumida en-aut-mei=Shinya kn-aut-name=角田晋哉 kn-aut-sei=角田 kn-aut-mei=晋哉 aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=CericMajda kn-aut-sei=Ceric kn-aut-mei=Majda aut-affil-num=3 ORCID= en-aut-name=YamamotoKazuhiro en-aut-sei=Yamamoto en-aut-mei=Kazuhiro kn-aut-name=山本和弘 kn-aut-sei=山本 kn-aut-mei=和弘 aut-affil-num=4 ORCID= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡邊雅二 kn-aut-sei=渡邊 kn-aut-mei=雅二 aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 affil-num=5 en-affil= kn-affil=岡山大学 en-keyword=tsunami kn-keyword=tsunami en-keyword=finite difference kn-keyword=finite difference en-keyword=staggered grid kn-keyword=staggered grid en-keyword=leapfrog kn-keyword=leapfrog END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=1 article-no= start-page=1 end-page=6 dt-received= dt-revised= dt-accepted= dt-pub-year=2007 dt-pub=20070315 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Numerical study of biodegradation of xenobiotic polymers based on exogenous depolymerization model with time dependent degradation rate en-subtitle= kn-subtitle= en-abstract= kn-abstract=A mathematical model for exogenous depolymerization with time dependent degradation rate is analyzed in order to study the biodegradation of polyethylene glycol. The weight distribution with respect to the molecular weight before and after cultivation of microorganisms were analyzed an inverse problem to determine the time dependent degradation rate. Numerical techniques to solve the inverse problem and to simulate the transition of the weight distribution are described. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡邊雅二 kn-aut-sei=渡邊 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name=KawaiFusako en-aut-sei=Kawai en-aut-mei=Fusako kn-aut-name=河合富佐子 kn-aut-sei=河合 kn-aut-mei=富佐子 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 en-keyword=biodegradation kn-keyword=biodegradation en-keyword=polyethylene glycol kn-keyword=polyethylene glycol en-keyword=mathematical model kn-keyword=mathematical model en-keyword=numerical simulation kn-keyword=numerical simulation END start-ver=1.4 cd-journal=joma no-vol=11 cd-vols= no-issue=1 article-no= start-page=15 end-page=18 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=20060315 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Numerical Techniques for Simulation of Tsunami Based on Finite Elements en-subtitle= kn-subtitle= en-abstract= kn-abstract=Numerical techniques to simulate tsunamis are described. Partial differential equations are reduced to a system of ordinary differential equations to which appropriate numerical solvers can be applied. The techniques are illustrated with an example in which tsunami due to an earthquake is simulated. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=LiuYing kn-aut-sei=Liu kn-aut-mei=Ying aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=WangMing Jun kn-aut-sei=Wang kn-aut-mei=Ming Jun aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=tsunami kn-keyword=tsunami en-keyword=finite elements kn-keyword=finite elements en-keyword=numerical simulation kn-keyword=numerical simulation END start-ver=1.4 cd-journal=joma no-vol=10 cd-vols= no-issue=1 article-no= start-page=23 end-page=28 dt-received= dt-revised= dt-accepted= dt-pub-year=2005 dt-pub=20050228 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Computational Analysis of Currents Generated in Kojima Lake Based on Updated Topographical Data en-subtitle= kn-subtitle= en-abstract= kn-abstract=Topographical data of Kojima Lake have been updated by applying data obtained after dredging. Together with tide level of Kojima Bay and water levels of Kurashiki River and Sasagase river, the information was incorporated in computational analysis of unsteady flows generated in the lake when the water was discharged from Kojima Lake to Kojima, Bay. A finite element method was applied to equations governing unsteady flows, and the transition of discharge was obtained. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=LiuYing kn-aut-sei=Liu kn-aut-mei=Ying aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=WangMing Jun kn-aut-sei=Wang kn-aut-mei=Ming Jun aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=water environment kn-keyword=water environment en-keyword=finite element method kn-keyword=finite element method en-keyword=numerical simulation kn-keyword=numerical simulation END start-ver=1.4 cd-journal=joma no-vol=26 cd-vols= no-issue= article-no= start-page=17 end-page=22 dt-received= dt-revised= dt-accepted= dt-pub-year=2004 dt-pub=200411 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Analysis of biodegradability for polyethylene glycol via numerical simulation kn-title=数値シミュレーションによるポリエチレングリコール生分解性解析 en-subtitle= kn-subtitle= en-abstract= kn-abstract=We examined the biodegradability of polyethylene glycol by analyzing gel permeation chromatography patterns, which were obtained before and after cultivation of a microbial consortium E-1 in culture media containing polyethylene glycol as its sole carbon source. We solved an inverse problem of the initial value problem, which consists of an exogenous depolymerization model and the initial weight distribution, in order to determine an oxidation rate, for which the solution of the initial value problem also satisfies the final condition. Given the oxidation rate, we simulated the transition of the weight distribution solving the initial value problem. We interpret the result that reflects a physical significance of the molecular weight on the oxidation rate, and reach a conclusion concerning the role of the membrane transport in exogenous depolymerization processes. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name=KawaiFusako en-aut-sei=Kawai en-aut-mei=Fusako kn-aut-name=河合富佐子 kn-aut-sei=河合 kn-aut-mei=富佐子 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=岡山大学環境理工学部 affil-num=2 en-affil= kn-affil=岡山大学資源生物科学研究所 en-keyword=biodegradation kn-keyword=biodegradation en-keyword=polyethylene glycol kn-keyword=polyethylene glycol en-keyword=exogenous depolymerization kn-keyword=exogenous depolymerization en-keyword=mathematical model kn-keyword=mathematical model en-keyword=numerical simulation kn-keyword=numerical simulation END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=1 article-no= start-page=59 end-page=64 dt-received= dt-revised= dt-accepted= dt-pub-year=2004 dt-pub=20040227 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Study on Effects of the Density Current Generator by Experiment and Measurement kn-title=実験と計測に基づく密度流拡散装置の効果に関する考察 en-subtitle= kn-subtitle= en-abstract= kn-abstract=The density current generator (Manufacturer: Nakashima Propeller Co., Ltd., Patent owner: Hitachi Metals, Ltd.) is designed to generate vertical circulation over a wide water area harnessing the density current effect. We present some experimental results that we obtained using a float equipped with a GPS unit to study water flows generated by a density current generator unit set in S-Reservoir in Okayama Prefecture. We also present some measured results concerning the water temperature around the unit. We discuss its effects observing the experimental results and the measured results. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name=YamatogiToshio en-aut-sei=Yamatogi en-aut-mei=Toshio kn-aut-name=山磨敏夫 kn-aut-sei=山磨 kn-aut-mei=敏夫 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=ナカシマプロペラ株式会社技術本部開発グループ en-keyword=density current kn-keyword=density current en-keyword=stratification kn-keyword=stratification en-keyword=water environment kn-keyword=water environment END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=1 article-no= start-page=53 end-page=58 dt-received= dt-revised= dt-accepted= dt-pub-year=2004 dt-pub=20040227 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Experimental and Computational Water Analysis for Kojima Lake en-subtitle= kn-subtitle= en-abstract= kn-abstract=We study a wind-generated current in Kojima Lake. We introduce an experimantal result which was obtained using a float equipped with a GPS unit. We also present a result of numerical study in which a result from finite element analysis of flow is applied to the momentum equation of the float to simulate its motion. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=NumaguchiSatoshi kn-aut-sei=Numaguchi kn-aut-mei=Satoshi aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=Med MahmoudOuld Med Lemine kn-aut-sei=Med Mahmoud kn-aut-mei=Ould Med Lemine aut-affil-num=2 ORCID= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 en-keyword=water environment kn-keyword=water environment en-keyword=global positioning system kn-keyword=global positioning system en-keyword=numerical simulation kn-keyword=numerical simulation END start-ver=1.4 cd-journal=joma no-vol=25 cd-vols= no-issue= article-no= start-page=25 end-page=32 dt-received= dt-revised= dt-accepted= dt-pub-year=2003 dt-pub=200308 dt-online= en-article= kn-article= en-subject= kn-subject= en-title=Analysis of polymeric biodegradability based on experimental results and numerical simulation kn-title=実験結果と数値シミュレーションによるポリマー生分解性解析 en-subtitle= kn-subtitle= en-abstract= kn-abstract=We describe techniques that we developed previously in studies of biodegradation of polymeric compounds. We present some experimental results concerning biodegradation of polyethylene. We introduce a mathematical model that govern the evolution of the weight distribution, and show how its inverse problem can be analyzed. We also introduce a mathematical model that governs the evolution of the weight distribution of polymeric compound subjected to enzymatic degradation, and present some numerical results concerning enzymatic degradation of polyvinyl alcohol. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name=KawaiFusako en-aut-sei=Kawai en-aut-mei=Fusako kn-aut-name=河合富佐子 kn-aut-sei=河合 kn-aut-mei=富佐子 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=岡山大学環境理工学部環境数理学科 affil-num=2 en-affil= kn-affil=岡山大学資源生物科学研究所 en-keyword=biodegradation kn-keyword=biodegradation en-keyword=mathematical model kn-keyword=mathematical model en-keyword=numerical simulation kn-keyword=numerical simulation en-keyword=polyethylene kn-keyword=polyethylene en-keyword=polyvinyl alcohol kn-keyword=polyvinyl alcohol END start-ver=1.4 cd-journal=joma no-vol=8 cd-vols= no-issue=1 article-no= start-page=23 end-page=26 dt-received= dt-revised= dt-accepted= dt-pub-year=2003 dt-pub=200303 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An Experimental Study of Unsteady Flows Generated in Kojima Lake en-subtitle= kn-subtitle= en-abstract= kn-abstract=The global positioning system (GPS) is utilized for analysis of flows in the water environment. A float equipped with a GPS unit is designed to drift on the surface of the water. Its driving force is the fluid resistance exerted on a pair of rectangular plates. While it travels over the surface, the GPS unit evaluates its position every second, and spatiotemporal data that specify its motion are transmitted to be recorded. Results of experiments conducted to study unsteady flows generated in Kojima Lake are introduced. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=NumaguchiSatoshi kn-aut-sei=Numaguchi kn-aut-mei=Satoshi aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 en-keyword=water environment kn-keyword=water environment en-keyword=global positioning system kn-keyword=global positioning system END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=1 article-no= start-page=39 end-page=44 dt-received= dt-revised= dt-accepted= dt-pub-year=2002 dt-pub=20020322 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Numerical Analysis and an Experimental Study of an Unsteady Flow in Kojima Lake en-subtitle= kn-subtitle= en-abstract= kn-abstract=We present some results of a finite element analysis for an unsteady flow in Kojima Lake. We also present an experimental result. The global positioning system was utilized in the experiment in order to record the temporal and the spatial data of a float traveling with the driving force of the fluid resistance. The spatial and temporal data were recorded to examine their correspondence with analytical results. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 en-keyword=lake flow kn-keyword=lake flow en-keyword=numerical simulation kn-keyword=numerical simulation en-keyword=finite element method kn-keyword=finite element method en-keyword=global positioning system kn-keyword=global positioning system END start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue=1 article-no= start-page=11 end-page=15 dt-received= dt-revised= dt-accepted= dt-pub-year=2001 dt-pub=20010228 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An Experimental Evaluation of Lake Flow Simulation en-subtitle= kn-subtitle= en-abstract= kn-abstract=The global positioning system is utilized in lake flow analysis to facilitate experimental evaluation for numerical results of a lake flow simulation. In our lake flow experiment a float travels on the lake surface receiving the fluid resistance due to lake flow, while a global positioning system receiver keeps track of its position. A momentum equation is derived when the product of the float mass and its acceleration is set equal to the driving force. The temporal change in the position of the float can be simulated when numerical solutions of lake flow equations are given. A comparison of numerical results and experimental data leads to an evaluation of the numerical simulation of lake flow. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= en-aut-name=KunisadaShigeyuki en-aut-sei=Kunisada en-aut-mei=Shigeyuki kn-aut-name=國貞茂幸 kn-aut-sei=國貞 kn-aut-mei=茂幸 aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 en-keyword=lake flow kn-keyword=lake flow en-keyword=numerical simulation kn-keyword=numerical simulation en-keyword=GPS-float kn-keyword=GPS-float en-keyword=finite element method kn-keyword=finite element method END start-ver=1.4 cd-journal=joma no-vol=5 cd-vols= no-issue=1 article-no= start-page=31 end-page=34 dt-received= dt-revised= dt-accepted= dt-pub-year=2000 dt-pub=20000229 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Numerical Analysis of Unsteady Flow in Kojima Lake en-subtitle= kn-subtitle= en-abstract= kn-abstract=We study unsteady flow that models lake flow in Kojima Lake. We assume that a lake is connected to another area with gates, and that those gates are opened when the water level outside the gates is lower than the water level of the lake. We study unsteady flow due to the opening of the gates. We analyze the problem with the finite element method, and take detailed structures of the gates into account. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 en-keyword=unsteady flow kn-keyword=unsteady flow en-keyword=lake flow kn-keyword=lake flow en-keyword=finite element method kn-keyword=finite element method END start-ver=1.4 cd-journal=joma no-vol=4 cd-vols= no-issue=1 article-no= start-page=1 end-page=6 dt-received= dt-revised= dt-accepted= dt-pub-year=1999 dt-pub=19990226 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Circadian Oscillations in Systems of Biochemical Oscillators Coupled to Stationary Systems en-subtitle= kn-subtitle= en-abstract= kn-abstract=According ot previous studies, we may expect that slow oscillations can occur in dynamics of a parameterized family of systems in which a biochemical oscillator is coupled to a stationary systems. We introduce some numerical results that confirm our expectation. The results suggest that it is possible for slow oscillations to occur in dynamics of a system in which an active oscillatory unit is coupled to a passive medium, and that it is possible for circadian oscillations to arise from fast glycolytic oscillations in such a coupled system. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 en-keyword=circadian rhythm kn-keyword=circadian rhythm en-keyword=glycolytic oscillation kn-keyword=glycolytic oscillation en-keyword=nonlinear oscillator kn-keyword=nonlinear oscillator END start-ver=1.4 cd-journal=joma no-vol=3 cd-vols= no-issue=1 article-no= start-page=11 end-page=24 dt-received= dt-revised= dt-accepted= dt-pub-year=1998 dt-pub=19980114 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A numerical analysis of slow oscillations in dynamics of coupled systems en-subtitle= kn-subtitle= en-abstract= kn-abstract=We study a system that models a problem in which an oscillatory unit is coupled to a passive medium. We analyze the case in which an RCL circuit is coupled to an RC circuit. Some numerical results indicate when slow oscillations occur in coupled systems. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 en-keyword=coupled circuits kn-keyword=coupled circuits en-keyword=Van der Pol's equation kn-keyword=Van der Pol's equation en-keyword=slow oscillations kn-keyword=slow oscillations END start-ver=1.4 cd-journal=joma no-vol=2 cd-vols= no-issue=1 article-no= start-page=19 end-page=24 dt-received= dt-revised= dt-accepted= dt-pub-year=1997 dt-pub=19970110 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=On Long-Period Oscillations in Coupled Systems of Nonlinear Oscillators and Stationary Systems en-subtitle= kn-subtitle= en-abstract= kn-abstract=We study a system obtained by coupling a nonlinear oscillator and a stationary system. We analyze the dynamics in a singular limit and show that asymptotically orbitally stable periodic solutions can exist. We also show how a slow oscillation can arise in the coupled system. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 END start-ver=1.4 cd-journal=joma no-vol=1 cd-vols= no-issue=1 article-no= start-page=47 end-page=53 dt-received= dt-revised= dt-accepted= dt-pub-year=1996 dt-pub=199603 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Computational water analysis in an artificial lake: Kojima Lake case en-subtitle= kn-subtitle= en-abstract= kn-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. en-copyright= kn-copyright= en-aut-name=SasakiToru en-aut-sei=Sasaki en-aut-mei=Toru kn-aut-name=佐々木徹 kn-aut-sei=佐々木 kn-aut-mei=徹 aut-affil-num=1 ORCID= en-aut-name=IshikawaHirofumi en-aut-sei=Ishikawa en-aut-mei=Hirofumi kn-aut-name=石川洋文 kn-aut-sei=石川 kn-aut-mei=洋文 aut-affil-num=2 ORCID= en-aut-name=KajiwaraTsuyoshi en-aut-sei=Kajiwara en-aut-mei=Tsuyoshi kn-aut-name=梶原毅 kn-aut-sei=梶原 kn-aut-mei=毅 aut-affil-num=3 ORCID= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 affil-num=2 en-affil= kn-affil=岡山大学 affil-num=3 en-affil= kn-affil=岡山大学 affil-num=4 en-affil= kn-affil=岡山大学 en-keyword=Kojima lake kn-keyword=Kojima lake en-keyword=Water analysis kn-keyword=Water analysis en-keyword=Finite element method kn-keyword=Finite element method END start-ver=1.4 cd-journal=joma no-vol=1 cd-vols= no-issue=1 article-no= start-page=55 end-page=64 dt-received= dt-revised= dt-accepted= dt-pub-year=1996 dt-pub=199603 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=On Resonance in Periodically Forced Oscillators and Coupled Systems of Excitable Systems and Nonlinear Oscillators en-subtitle= kn-subtitle= en-abstract= kn-abstract=We analyze some mathematical problems that arise in studies of phenomena observed in the cardiac action. We illustrate a method to characterize the response of a nonlinear oscillator to an external forcing, and introduce some numerical results. We also introduce some results of numerical computation in an example of a coupled system of an excitable system and a nonlinear oscillator. en-copyright= kn-copyright= en-aut-name=WatanabeMasaji en-aut-sei=Watanabe en-aut-mei=Masaji kn-aut-name=渡辺雅二 kn-aut-sei=渡辺 kn-aut-mei=雅二 aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=岡山大学 en-keyword=periodic forcing kn-keyword=periodic forcing en-keyword=nonlinear oscillators kn-keyword=nonlinear oscillators en-keyword=excitable systems kn-keyword=excitable systems en-keyword=couples systems. kn-keyword=couples systems. END