検索結果 1797 件
| JaLCDOI | 10.18926/fest/11552 |
|---|---|
| フルテキストURL | 003_001_003.pdf |
| 著者 | 中島 惇| |
| 抄録 | The existence of a derivation in a near-ring is not known. We construct derivations on 2×2 matrix near-ring in the sense of [MW]. |
| キーワード | Near-ring matrix near-ring derivation |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 1998-01-14 |
| 巻 | 3巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 3 |
| ISSN | 1341-9099 |
| 言語 | 日本語 |
| 論文のバージョン | publisher |
| NAID | 120002313635 |
| JaLCDOI | 10.18926/fest/11548 |
|---|---|
| フルテキストURL | 005_001_006.pdf |
| 著者 | 石川 洋文| 石井 明| 金子 明| |
| 抄録 | 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. |
| キーワード | Plasmodium vivax computer simulation hypnozoite mass drug administration relapse |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2000-02-29 |
| 巻 | 5巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 6 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313438 |
| JaLCDOI | 10.18926/fest/11526 |
|---|---|
| フルテキストURL | 006_025_034.pdf |
| 著者 | 山西 芳裕| 田中 豊| |
| 抄録 | In functional principal component analysis (PCA), we treat the data that consist of functions not of vectors (Ramsay and Silverman, 1997). It is an attractive methodology, because we often meet the cases where we wish to apply PCA to such data. But, to make this method widely useful, it is desirable to study advantages and disadvantages in actual applications. As alternatives to functional PCA, we may consider multivariate PCA applied to 1) original observation data, 2) sampled functional data with appropriate intervals, and 3) coefficients of basis function expansion. Theoretical and numerical comparison is made among ordinary functional PCA, penalized functional PCA and the above three multivariate PCA. |
| キーワード | Functional data Multivariate data Principal component analysis Eigenvalue Eigenvecotor |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2001-02-28 |
| 巻 | 6巻 |
| 号 | 1号 |
| 開始ページ | 25 |
| 終了ページ | 34 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313939 |
| JaLCDOI | 10.18926/fest/11524 |
|---|---|
| タイトル（別表記） | Speeds of travelling wave solutions in a mathematical model of some infectious disease in predator-prey system |
| フルテキストURL | 006_017_023.pdf |
| 著者 | 梶原 毅| 沖田 知毅| |
| 抄録 | 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. |
| キーワード | Travelling wave Infectious disease |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2001-02-28 |
| 巻 | 6巻 |
| 号 | 1号 |
| 開始ページ | 17 |
| 終了ページ | 23 |
| ISSN | 1341-9099 |
| 言語 | 日本語 |
| 論文のバージョン | publisher |
| NAID | 120002313731 |
| JaLCDOI | 10.18926/fest/11523 |
|---|---|
| フルテキストURL | 007_039_044.pdf |
| 著者 | 渡辺 雅二| |
| 抄録 | 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. |
| キーワード | lake flow numerical simulation finite element method global positioning system |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2002-03-22 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 39 |
| 終了ページ | 44 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313386 |
| JaLCDOI | 10.18926/fest/11522 |
|---|---|
| フルテキストURL | 006_011_015.pdf |
| 著者 | 渡辺 雅二| 國貞 茂幸| |
| 抄録 | 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. |
| キーワード | lake flow numerical simulation GPS-float finite element method |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2001-02-28 |
| 巻 | 6巻 |
| 号 | 1号 |
| 開始ページ | 11 |
| 終了ページ | 15 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313583 |
| JaLCDOI | 10.18926/fest/11521 |
|---|---|
| フルテキストURL | 007_031_038.pdf |
| 著者 | 張 方紅| 田中 豊| |
| 抄録 | 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. |
| キーワード | Local influence influence function equality constraints |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2002-03-22 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 31 |
| 終了ページ | 38 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313336 |
| JaLCDOI | 10.18926/fest/11519 |
|---|---|
| フルテキストURL | 007_023_029.pdf |
| 著者 | 成 祉旻| 梁 祐誠| 田中 豊| |
| 抄録 | 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. |
| キーワード | Covariance Selection Local Influence Influence Function Stepwise Procedure |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2002-03-22 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 23 |
| 終了ページ | 29 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002314018 |
| JaLCDOI | 10.18926/fest/11516 |
|---|---|
| フルテキストURL | 006_001_010.pdf |
| 著者 | 冨田 誠| 大竹 正徳| |
| 抄録 | 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. |
| キーワード | Excess relative risks cancer mortalities antagonistic effects prospective studies atomic bomb survivors |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2001-02-28 |
| 巻 | 6巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 10 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313814 |
| JaLCDOI | 10.18926/fest/11515 |
|---|---|
| タイトル（別表記） | Stability analysis of mathematical models of infectious disease |
| フルテキストURL | 007_017_021.pdf |
| 著者 | 村瀬 晶子| 佐々木 徹| 梶原 毅| |
| 抄録 | 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. |
| キーワード | mathematical model infectious disease dynamics in vivo stability analysis symbolic calculation |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2002-03-22 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 17 |
| 終了ページ | 21 |
| ISSN | 1341-9099 |
| 言語 | 日本語 |
| 論文のバージョン | publisher |
| NAID | 120002313783 |
| JaLCDOI | 10.18926/fest/11512 |
|---|---|
| フルテキストURL | 007_007_016.pdf |
| 著者 | 石井 裕之| 石川 洋文| 大賀 潔生| |
| 抄録 | 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. |
| キーワード | Lymphatic filariasis mathematical model Pondicherry vector control Wuchereria bancrofti |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2002-03-22 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 7 |
| 終了ページ | 16 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313471 |
| JaLCDOI | 10.18926/fest/11510 |
|---|---|
| フルテキストURL | 007_001_005.pdf |
| 著者 | 大賀 潔生| 石川 洋文| 土井 陸雄| 石井 裕之| |
| 抄録 | 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. |
| キーワード | Echinococcus multilocularis food habit of foxes Hokkaido population dynamics vole |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2002-03-22 |
| 巻 | 7巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 5 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| JaLCDOI | 10.18926/fest/11497 |
|---|---|
| フルテキストURL | 008_023_026.pdf |
| 著者 | 渡辺 雅二| Numaguchi Satoshi| |
| 抄録 | 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. |
| キーワード | water environment global positioning system |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2003-03 |
| 巻 | 8巻 |
| 号 | 1号 |
| 開始ページ | 23 |
| 終了ページ | 26 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313912 |
| JaLCDOI | 10.18926/fest/11487 |
|---|---|
| フルテキストURL | 008_001_007.pdf |
| 著者 | Tsunekuni Yasuhiro| Ohga Yukio| 石川 洋文| |
| 抄録 | In 1990s, there were rapid increases in the number of HIV epidemics and AIDS cases in Thailand, Southeast Asia. In particular the risk of HIV infection was very high among female prostitutes who played a large part in the transmission of HIV infection. We formulated a mathematical model for the transmission of HIV in prostitutes. We carried out the model simulations to analyze the incipient spread of HIV infection and the effect of AIDS prevention methods in prostitutes. The simulation of our model indicates that even if the effect of AIDS prevention methods such as the recommendation of condom use for commercial sex workers would block the transmission at rate by 70%, the elimination of the HIV epidemic is still beyond attainment. |
| キーワード | AIDS HIV prostitution Thailand transmission model |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2003-03 |
| 巻 | 8巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 7 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002314019 |
| JaLCDOI | 10.18926/fest/11485 |
|---|---|
| フルテキストURL | 010_029_039.pdf |
| 著者 | Ju Xian Meng| |
| 抄録 | The generalized Grothendieck-Witt ring of nonsingular Hermitian forms with positioning map is the cartesian product of the ordinary Grothendieck-Witt ring of nonsingular Hermitian forms and a map ring. We study the generalized Grothendieck-Witt ring by computing the map ring. |
| キーワード | Grothendieck Witt ring orbit GAP |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2005-02-28 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 29 |
| 終了ページ | 39 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313655 |
| JaLCDOI | 10.18926/fest/11484 |
|---|---|
| フルテキストURL | 010_023_028.pdf |
| 著者 | 渡辺 雅二| Liu Ying| Wang Ming Jun| |
| 抄録 | 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. |
| キーワード | water environment finite element method numerical simulation |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2005-02-28 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 23 |
| 終了ページ | 28 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313649 |
| JaLCDOI | 10.18926/fest/11481 |
|---|---|
| フルテキストURL | 010_009_011.pdf |
| 著者 | 梶原 毅| 佐々木 徹| |
| 抄録 | 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. |
| キーワード | Permanence dynamical system pathogen |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2005-02-28 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 9 |
| 終了ページ | 11 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313596 |
| JaLCDOI | 10.18926/fest/11479 |
|---|---|
| フルテキストURL | 010_001_007.pdf |
| 著者 | Wang Xiao Dong| 石川 洋文| |
| 抄録 | The one-way hash function plays an important role in digital signatures and message authentication from the viewpoint of security. No effective attacking method has been discovered to the algorithm of hash function standard. In this study, we tried to attack SHA-256 in encryption mode using linear and differential cryptanalysis to solve a private key. We deduced that an estimate of the private key would require huge known and chosen plaintexts in both linear and differential cryptanalysis, and that it would be difficult to decipher SHA-256 in view of the required computation. |
| キーワード | differential cryptanalysis encryption mode hash function linear cryptanalysis SHA-256 |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2005-02-28 |
| 巻 | 10巻 |
| 号 | 1号 |
| 開始ページ | 1 |
| 終了ページ | 7 |
| ISSN | 1341-9099 |
| 言語 | 日本語 |
| 論文のバージョン | publisher |
| NAID | 120002313630 |
| JaLCDOI | 10.18926/fest/11456 |
|---|---|
| フルテキストURL | 009_053_058.pdf |
| 著者 | Numaguchi Satoshi| Med Mahmoud Ould Med Lemine| 渡辺 雅二| |
| 抄録 | 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. |
| キーワード | water environment global positioning system numerical simulation |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2004-02-27 |
| 巻 | 9巻 |
| 号 | 1号 |
| 開始ページ | 53 |
| 終了ページ | 58 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313924 |
| JaLCDOI | 10.18926/fest/11455 |
|---|---|
| フルテキストURL | 009_045_051.pdf |
| 著者 | Iuchi Takuma| 梶原 毅| |
| 抄録 | Qualitative analysis for the model of HIV infection in vivo presented by Perelson and Nelson are developed. The local stability analysis is done for the interior equilibrium, and it is shown that, for some paramter value, the interior equilibrium can be unstable and a Hopf bifurcation can occur. It is shown that the boundary equilibrium is globally asymptotically stable. Last, it is shown that this system is permanent. |
| キーワード | HIV Mathematical model Stability Liapunov function |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2004-02-27 |
| 巻 | 9巻 |
| 号 | 1号 |
| 開始ページ | 45 |
| 終了ページ | 51 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313809 |