result 2732 件
| JaLCDOI | 10.18926/fest/11575 |
|---|---|
| FullText URL | 005_099_105.pdf |
| Author | Taniguchi, Takeo| |
| Abstract | Delaunay triangulation, a geometric subdivision of any convex domain, is often used as a finite element modeling method, but there are still several problems, which originally come from the characteristics of Delaunay triangulation. One problem appears when we remove some nodes which are already introduced for the triangulation. In this case we aim to obtain the triangulation without nodes by partial modification of the Delaunay triangulation with the node. Another problem occurs when tetrahedra with zero volume are generated by Delaunay triangulation. In this case they must be removed for the numerical analysis in order to guarantee the numerical stability and good numerical solutions. In this paper these two problems occuring at the use of Delaunay triangulation are theoretically discussed. |
| Keywords | Delaunay triangulation Degeneracy Tetrahedron Automatic mesh generation |
| 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 | 99 |
| End Page | 105 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313608 |
| JaLCDOI | 10.18926/fest/11570 |
|---|---|
| FullText URL | 003_105_120.pdf |
| Author | Kidtimonton Surasri| Mitsuno, Toru| |
| Abstract | Two optimization models are formulated based on different objectives for assisting the irrigation planner in making decision on agricultural planning during drought year. The sensitive degree of water shortage area in the irrigation project are classified by those models. They are solved by simplex method. Firstly, the Two-phase method is applied to analyze the artificial variables in the formulated model. Then, the formulated model is modified after getting rid of the artificial variables to obtain the feasible solution. The agricultural planning is planned by considering the classified area with social equity and economic improvement. Crop diversification is introduced to conduct in the very sensitive water shortage area and intermittent irrigation system is introduced to operate in the moderately sensitive water shortage area. The integrated farming system, the separation of land owner and cultivator and the disposition of substitute lots system are also suggested to conduct in this study project. |
| Keywords | agricultural planning Two-phase method integrated farming sensitive water shortage disposition of substitute lots system |
| 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 | 105 |
| End Page | 120 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313819 |
| JaLCDOI | 10.18926/fest/11564 |
|---|---|
| FullText URL | 005_047_056.pdf |
| Author | Otake, Masanori| Ohtsubo, Ryusuke| Tomita, Makoto| Tanaka, Yutaka| |
| Abstract | Main content of this paper is to classify IQ individuals into two categories of normal and abnormal groups. It is too difficult to divide IQ individuals into two groups of normal IQ group and abnormal group because of sparse number of cases with mental retardation. Therefore, we examined a normality of 1673 IQ individuals, but a significant difference was noted for the IQ data. The lowest three mentally retarded cases of less than or equal to 59 IQ score were excluded, the IQ data then fitted to a normal distribution well. The critical value which minimizes the probability of classification is obtained on the basis on an approximate technique with regard to normality. An approximate probability of misclassification for individuals at random from mixture of two normal populations is 25.5%. |
| Keywords | Compound distribution normality Prenatal exposure IQ misclassification |
| 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 | 47 |
| End Page | 56 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313674 |
| JaLCDOI | 10.18926/fest/11563 |
|---|---|
| FullText URL | 003_047_062.pdf |
| Author | Otake, Masanori| Tanaka, Yutaka| Lee Sunghee| |
| Abstract | Exposure to ionizing radiation has been testified to have harmful effects on the developing human brain, particularly in the highly vulnerable period of 8-15 weeks after ovulation as an incereased frequency of severe mental retardation. However, the distribution of cases of severe mental retardation suggests a threshold in the low dose region. Data are composed of a binary (1,0) for mentally retarded or normal individuals. The statistical approaches with a threshold are conceivable for a simple, odds, logistic and Gompertz regression models. Estimation of threshold and 100(1-α)% confidence limits are derived from the maximum likelihood technique based on a profile approach. |
| Keywords | mental retardation threshold model prenatal exposure profile approach atomic bombings |
| 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 | 47 |
| End Page | 62 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313935 |
| JaLCDOI | 10.18926/fest/11561 |
|---|---|
| FullText URL | 005_035_046.pdf |
| Author | Choi, Seung Bae| Tanaka, Yutaka| |
| Abstract | Spatial data is analyzed in three stages of 1) estimating the variograms, 2) fitting a model for the estimated variograms and 3) predicting the value at unknown location based on the information at known locations (kriging). Recently, it has become a subject of interest to detect influential observations in these stages. Choi and Tanaka(1999) have derived influence functions in the above three stages and have proposed sensitivity analysis procedure. So far influence functions have only been derived for variograms by Gunst and Hartfield(1996). The present article makes a comparison of the performances between those influence functions for variograms derived by Choi and Tanaka(1999) and by Gunst and Hartfield(1996). A real numerical example is given to discuss the validity or usefulness of those influence functions. |
| Keywords | Stationary spatal data Influence function Sample variogram Median-polish residual |
| 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 | 35 |
| End Page | 46 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313332 |
| JaLCDOI | 10.18926/fest/11559 |
|---|---|
| FullText URL | 005_031_034.pdf |
| Author | Watanabe, Masaji| |
| 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. |
| Keywords | unsteady flow lake flow finite element method |
| 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 | 31 |
| End Page | 34 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313848 |
| 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 | Japanese |
| File Version | publisher |
| NAID | 120002313498 |
| JaLCDOI | 10.18926/fest/11556 |
|---|---|
| FullText URL | 003_011_024.pdf |
| Author | Watanabe, Masaji| |
| 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. |
| Keywords | coupled circuits Van der Pol's equation slow oscillations |
| 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 | 11 |
| End Page | 24 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313697 |
| 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 | Japanese |
| File Version | publisher |
| NAID | 120002313531 |
| 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 | Japanese |
| File Version | publisher |
| NAID | 120002313400 |
| JaLCDOI | 10.18926/fest/11548 |
|---|---|
| FullText URL | 005_001_006.pdf |
| Author | Ishikawa, Hirofumi| Ishii, Akira| Kaneko, Akira| |
| Abstract | We have estimated the degree of transmission of Plasmodium vivax malaria in Vanuatu Islands, eastern Melanesia with the aid of the computer simulations, which has been carried out on the platform of a mathematical transmission model. The malaria caused by Plasmodium vivax has a relapse character, which arises from hypnozoites in the liver. This phenomen makes a malaria control strategy difficult. When the mass drug administration is executed, the prevalence of Plasmodium vivax decreases moderately as compared with that of Plasmodium falciparum, and it recovers before long being affected by the relapses. The simulations suggest that one cannot attain the eradication of Plasmodium vivax malaria without the concentrated execution of the mass drug administration and the vector control that fairly reduces the vactorial capacity. |
| Keywords | Plasmodium vivax computer simulation hypnozoite mass drug administration relapse |
| 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 | 1 |
| End Page | 6 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313438 |
| JaLCDOI | 10.18926/fest/11528 |
|---|---|
| Title Alternative | Damage factors analysis for small embankment dams due to the Hyogoken-Nambu earthquake special to Hokudan Town |
| FullText URL | 007_055_074.pdf |
| Author | Fujii, Hiroaki| Kunimasa, Kana| Nanba, Akiyo| Yokomizo, Takayuki| Nishimura, Shin-ichi| Shimada, Kiyoshi| Hori, Toshio| Nishiyama, Tatsuro| Wakitani, Yoshiaki| |
| Abstract | This study was performed to clarify which factors affected damage to take-ike (small embankment dams for irrigation in Japanese) of Hokudan Town on Awaji Island in western Japan due to Hyogoken-Nambu earthquake. Multivariate and ordinary statistical analysis were carried out using documentary data (181 damaged and 328 undamaged dams), and ordinary one was done for the results investigated in situ. The model for the multivariate analysis was created with 13 items and 94 categories for 4 groups (Location, Geology Structure, and History of Dam). As a result, the factors causing to damage for dam are (1) the nearest fault (Nojima, Mizukoshi and D2), (2) embankment volume (the larger the more), (3) angle of crest axis to epicenter (diagonal and normal), (4) distance to the nearest fault (less than 500 m), (5) distance to the epicenter (8 to 14 km which almost agree to the location of seismic intensity 7 JMA), (6) play view of dam axis (3 or 4 axes), (7) angle of crest axis to nearest fault (diagonal and normal), (8) elevation of dam site (over 100 m), (9) surface geology of dam site (non-cohesive soil), (10) era of construction (prior to 1891), and (11) soil properties of embankment (constructed of sand, smaller penetration resistance). |
| Keywords | Earth dam earthquake damage site investigation statistical analysis case study |
| 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 | 55 |
| End Page | 74 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002314039 |
| 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 | Japanese |
| File Version | publisher |
| NAID | 120002313453 |
| JaLCDOI | 10.18926/fest/11524 |
|---|---|
| Title Alternative | Speeds of travelling wave solutions in a mathematical model of some infectious disease in predator-prey system |
| FullText URL | 006_017_023.pdf |
| Author | Kajiwara, Tsuyoshi| Okita, Tomoki| |
| Abstract | In this paper we construct a simple mathematical model for infectious disease in a pradator-prey system, and study the speeds of travelling wave solutions of this model. We present a method of estimation of speeds and make a numerical study about this matter. |
| Keywords | Travelling wave Infectious disease |
| 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 | 17 |
| End Page | 23 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313731 |
| JaLCDOI | 10.18926/fest/11521 |
|---|---|
| FullText URL | 007_031_038.pdf |
| Author | Zhang, Fanghong| Tanaka, Yutaka| |
| Abstract | Relationship has been discussed by Tanaka and Zhang(1999) between the sensitivity analyses based on influence functions and on Cook's local influence, and it has been shown that equivalent results are obtained under general conditions by these analyses in statistical modeling without/with equality constraints. However, a condition implicitly assumed in the proof in Tanaka and Zhang(1999) in the case with equality constraints does not necessarily hold. The present paper gives a complete proof without assuming the condition. Also a formula for the normal curvature is derived for the convenience of practical computation. |
| Keywords | Local influence influence function equality constraints |
| 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 | 31 |
| End Page | 38 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313336 |
| JaLCDOI | 10.18926/fest/11519 |
|---|---|
| FullText URL | 007_023_029.pdf |
| Author | Sung, JiMin| Yang, WooSung| Tanaka, Yutaka| |
| Abstract | Analysis of covariance selection models is a useful multivariate method to analyze the covariance structure of a multivariate normal distribution. It is used to reveal cause-and-effect relationships. In the present paper we review the theory and study numerically how the stepwise procedure of covariance selection works in actual data analysis. Then we try to develop a method of influence analysis in covariance selection, and show a numerical example to illustrate the usefulness of the method of influence analysis. |
| Keywords | Covariance Selection Local Influence Influence Function Stepwise Procedure |
| 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 | 23 |
| End Page | 29 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002314018 |
| JaLCDOI | 10.18926/fest/11516 |
|---|---|
| FullText URL | 006_001_010.pdf |
| Author | Tomita, Makoto| Otake, Masanori| |
| Abstract | In many epidemiological and medical studies, a number of cancer motralities in catagorical classification may be considered as having Poisson distribution with person-years at risk depending upon time. The cancer mortalities have been evaluated by additive or multiplicative models with regard to background and excess risks based on several covariances such as sex, age at the time of bombings, time at exposure, or ionizing radiation, cigarette smoking habits, duration of smoking habits, etc. An interest herein to examine an additive, synergistic,or antagonistic relationship between radiation exposures and cigarette smoking habits for cancer mortalities. The results revealed a highly significant antagonistic influence for cancer mortalities from all nonhematologic findings, lung and respiratory system with negative interaction between radiation exposures and cigarette smoking amounts. |
| Keywords | Excess relative risks cancer mortalities antagonistic effects prospective studies atomic bomb survivors |
| 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 | 1 |
| End Page | 10 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313814 |
| 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 | Japanese |
| File Version | publisher |
| NAID | 120002313783 |
| JaLCDOI | 10.18926/fest/11512 |
|---|---|
| FullText URL | 007_007_016.pdf |
| Author | Ishii, Hiroyuki| Ishikawa, Hirofumi| Ohga, Yukio| |
| Abstract | We have constructed a stochastic transmission model for lymphatic filariasis caused by Wuchereria bancrofti, and have analyzed its prevalence using computer simulations. In Pondicherry, India, where Wuchereria bancrofti has been spreading, the Vector Control Research Centre has carried out an integrated vector control strategy against malaria and filariasis for five years (1981~1985) with good results reported. Our study was aimed at evaluating the effect of vector control in the context of Pondicherry, and in particular the continuous effect for the post-control period. In this paper, we have used the LYMFASIM model proposed by Plaisier et al., the carrying capacity model by Rochet and the population dynamics model by us. In the LYMFASIM model and the carrying capacity model, we have modified the quantities of parameters in order to fit the models to the parasitological, entomological and epidemiological data in Pondicherry. We have combined the improved LYMFASIM model with the other models. Through simulations of our combinated model, we have compared the prevalence rate in the human population as well as the mean number of L3-larvae in the mosquito population, with and without vector control. As a result, the simulations show that the prevalence rate would be restrained for a long time even if only a small continuous effect of the vector control remains in the post-control period. However, the mean number of L3-larvae would recovered within a short time comparatively. This is because of the differences in life spans between human and mosquito as well as the incubation periods between the adult worm in the human host and L3-larvae in the mosquito vector. |
| Keywords | Lymphatic filariasis mathematical model Pondicherry vector control Wuchereria bancrofti |
| 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 | 7 |
| End Page | 16 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313471 |
| JaLCDOI | 10.18926/fest/11510 |
|---|---|
| FullText URL | 007_001_005.pdf |
| Author | Ohga, Yukio| Ishikawa, Hirofumi| Doi, Rikuo| Ishii, Hiroyuki| |
| Abstract | In our study, we have investigated the influence of the intermediate host population density on the prevalence of Echinococcus multilocularis in the definitive host using a mathematical model of transmission. For the vole population (intermediate host) in Hokkaido, a model of population dynamics has been constructed in this paper which follows the seasonal and annual fluctuations. In the northeastern area, the vole density appears to fluctuate periodically with a 4 year cycle. The prevalence of Echinococcus multilocularis in the fox population (definitive host) can be affected by the density of vole through the fox ingesting infectious voles. Therefore we have prepared a food habit function of foxes and the logistic distribution has been proposed. The simulations which have been carried out using the mathematical model for transmission of Echinococcus multilocularis together with the vole dynamics have indicated that the prevalence in foxes is correlated and synchronized with the population dynamics of vole. In addition they have also made us recognize that it is necessary to introduce a suitable food habit function into the transmission model. |
| Keywords | Echinococcus multilocularis food habit of foxes Hokkaido population dynamics vole |
| 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 | 1 |
| End Page | 5 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
