検索結果 2117 件
| 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 |
| JaLCDOI | 10.18926/fest/11453 |
|---|---|
| フルテキストURL | 009_037_044.pdf |
| 著者 | Sung Jimin| 田中 豊| |
| 抄録 | There have been proposed so far many methods of statistical diagnostics in Cox regression for checking the goodness of the estimated model or checking the adequacy of the data. The former type contains the checking of the overall goodness of fit, the validity of the assumption of proportional hazards and the proper functional forms of the effects of covariates. While the latter type contains the checking whether there exist singly and/or jointly influential observations in the data set. In the present paper we study numerically the performances of various methods of diagnostics including our method of influence analysis for multiple-case diagnostics (Sung and Tanaka, 2003) by analyzing a real data set of lung cancer patients. |
| キーワード | Cox regression Influence function Local influence Influential Subsets Cox-Snell residuals Martingale residual Deviance residual |
| 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 | 37 |
| 終了ページ | 44 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313595 |
| JaLCDOI | 10.18926/fest/11452 |
|---|---|
| フルテキストURL | 011_015_018.pdf |
| 著者 | 渡辺 雅二| Liu Ying| Wang Ming Jun| |
| 抄録 | 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. |
| キーワード | tsunami finite elements 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 | 2006-03-15 |
| 巻 | 11巻 |
| 号 | 1号 |
| 開始ページ | 15 |
| 終了ページ | 18 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002314045 |
| JaLCDOI | 10.18926/fest/11451 |
|---|---|
| フルテキストURL | 009_027_036.pdf |
| 著者 | 中島 惇| |
| 抄録 | Let A/R be a ring extension and P a subset of Hom(A(R),A(R)). In his paper [5], K. Kishimoto introduced the notion of a P-Galois extension and gave several basic properties of these extensions. The author showed that these extensions are closely related to Hopf Galois extensions and the structure of quadratic or cubic P-Galois extensions over a field were given in [9] and [10]. Recently,the author classify commutative quartic P-Galois extensions over a field of characteristic not 2 in [11]. Continuing [11], we treat commutative quartic P-Galois extensions over a field of characteristic 2. |
| キーワード | Cyclic extension P-Galois extension Hopf Galois extension |
| 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 | 27 |
| 終了ページ | 36 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313989 |
| JaLCDOI | 10.18926/fest/11449 |
|---|---|
| フルテキストURL | 009_019_026.pdf |
| 著者 | Sakamura Kenichi| Dong Wang Xiao| 石川 洋文| |
| 抄録 | We have investigated the linear cryptanalysis of AES cipher in this article. As the previous encryption standard DES could be broken by the linear cryptanalysis, NIST decided a new encryption standard AES in 2000. We try to analyze one and two rounds AES cipher by the method of the linear cryptanalysis and learn the limits of this mehtod. AES cipher provides a conspicuous difficulty in breaking its keys because of small bias of its S-box. We report the experimental results of success rate and are led to conclusion that this method would not work well on more than 3 rounds to break keys. |
| キーワード | AES Chosen plaintext attack Linear cryptanalysis |
| 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 | 19 |
| 終了ページ | 26 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313376 |
| JaLCDOI | 10.18926/fest/11448 |
|---|---|
| フルテキストURL | 009_009_017.pdf |
| 著者 | Setiawan Agus| 垂水 共之| |
| 抄録 | Small Area Estimation (SAE) is the process of using statistical models to link survey outcome variables to a set of predictor variables known for small domains, in order to predict domain-level estimates. The need for detailed statistics on small area is constantly increasing. Small area estimation is becoming important in survey sampling due to a growing demand for reliable small area statistics from both public and private sectors. Bayesian hierarchical models provide a convenient framework for disease mapping and geographical correlation studies. Computation may be carried out using the freely-available WinBUGS software. Two approaches prediction to estimate total patient in small area i will be presented. For the purpose of this paper, the small area estimation in this context use data of Indnesia's population based on the 2000 census for the population of Jakarta and data of patient diarrhea from District Health Service of Jakarta. We interest to predict total patient of diarrhea as variable of interest and data population as auxiliary data from unsample for each small area. |
| キーワード | Auxiliary data Population density Sample survey Small area estimation WinBUGS |
| 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 | 9 |
| 終了ページ | 17 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313784 |
| JaLCDOI | 10.18926/fest/11436 |
|---|---|
| フルテキストURL | 012_063_070.pdf |
| 著者 | Saif Eideen S. A.| 谷口 健男| |
| 抄録 | The homogenization method is used to model steel fiber reinforced concrete SFRC by converting the random distribution of fibers to a periodic one. The periodic distribution is chosen to hold similar properties of the composite material in both perpendicular directions to represent an average approximation for the random distribution. The material is modeled as a composite with brittle matrix and elastic fibers. Two patterns of the unit cell are examined to establish the homogenized stiffiness matrix in elastic and plastic stages. A rigid plastic bonding is considered between matrix and fibers. The smeared crack model is used to represent the nonlinearity of concrete. The validity of the homogenized model is examined by comparing the numerical results with the experimental results. The results show good agreement with the experimental work when a suitable pattern of the unit cell is used. |
| キーワード | fiber reinforced concrete composite materials homogenization periodicity finite element |
| 出版物タイトル | 岡山大学環境理工学部研究報告 |
| 発行日 | 2007-03-15 |
| 巻 | 12巻 |
| 号 | 1号 |
| 開始ページ | 63 |
| 終了ページ | 70 |
| ISSN | 1341-9099 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002313536 |