result 2732 件
| JaLCDOI | 10.18926/fest/11502 |
|---|---|
| FullText URL | 010_083_088.pdf |
| Author | Kankam-Yeboah Kwabena| Darko Philip K.| Nishigaki, Makoto| |
| Abstract | Groundwater has been recognised as the most cost-effective option of safe water supply to rural communities in Ghana. The demand for potable water has led to the drilling of a large number of boreholes in many parts of the country. To establish the threshold of groundwater development from storage in a major river catchment (Pra River) in South-West Ghana, studies on recharge to the weathered aquifer and statistical evaluations of specific capacity and potential yield have been carried out. The SACSMA conceptual hydrological modelling system was used for the recharge estimate. With recharge rate of 50 mm/yr, the natural groundwater resources in the basin was estimated to support a maximum withdrawal of 12 l/s for a 10 hour per day pumping. The groundwater resources potential of 1.6 l/sｋ㎡ could be considered the threshold of groundwater exploitation in similar river basins in South-West Ghana. A study into the relation between permeability and recharge under different conditions and scenarios is required to define their limiting role in groundwater resources development. |
| Keywords | Groundwater storage recharge aquifer specific capacity base flow hydrologic budget |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2005-02-28 |
| Volume | volume10 |
| Issue | issue1 |
| Start Page | 83 |
| End Page | 88 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313829 |
| JaLCDOI | 10.18926/fest/11495 |
|---|---|
| Title Alternative | A note on the effect of quadratic term on final pattern in Turing model |
| FullText URL | 008_019_022.pdf |
| Author | Yamauchi, Ken-ichi| Kajiwara, Tsuyoshi| |
| Abstract | The effect of the quadratic term on the final pattern in Turing model is disscussed numerically. Turing models are non linear reaction diffusion equations. Linear analysis for wave length is very useful to find evolving waves. But when a quadratic term appear in the equation, an initial wave can disappears and changes drastically to a spot which is independent of linear analysis. |
| Keywords | Turing instability Reaction Diffusion equation Quadratic term |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2003-03 |
| Volume | volume8 |
| Issue | issue1 |
| Start Page | 19 |
| End Page | 22 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313586 |
| Author | Ohtani, Yu| |
|---|---|
| Published Date | 2007-03-23 |
| Publication Title | |
| Content Type | Thesis or Dissertation |
| JaLCDOI | 10.18926/fest/11489 |
|---|---|
| Title Alternative | Considering variable selection criteria in correspondence analysis |
| FullText URL | 010_049_056.pdf |
| Author | Mori, Yuichi| Du, Xiao Dong| Iizuka, Masaya| |
| Abstract | Ordinary goodness of fit criteria in correspondence analysis are considered as variable selection criteria in case correspondence analysis which is one of multivariate methods without external variables can be applied. The goodness of fit criteria focused here are proportion of cumulative eigenvalues, proportion of cumulative squared-eigenvalues and proportion of cumulative off-diagonal fitness. Each criterion is applied to a couple of real data sets and evaluated with interpretation of the selection process and result (selected subset of variables). Four selection procedures such as backward elimination and forward-backward selection are also performed to compare with each other as well as with all possible selection procedure. These results illustrate that the criteria can be used as selection criteria to select a subset of variables in correspondence analysis and to assess categorical items (questions) in a survey (questionnaire). |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2005-02-28 |
| Volume | volume10 |
| Issue | issue1 |
| Start Page | 49 |
| End Page | 56 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313834 |
| JaLCDOI | 10.18926/fest/11487 |
|---|---|
| FullText URL | 008_001_007.pdf |
| Author | Tsunekuni Yasuhiro| Ohga Yukio| Ishikawa, Hirofumi| |
| Abstract | 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. |
| Keywords | AIDS HIV prostitution Thailand transmission model |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2003-03 |
| Volume | volume8 |
| Issue | issue1 |
| Start Page | 1 |
| End Page | 7 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002314019 |
| JaLCDOI | 10.18926/fest/11483 |
|---|---|
| Title Alternative | On Persistence in Dynamical Systems (Review) |
| FullText URL | 010_013_021.pdf |
| Author | Sasaki, Toru| Kajiwara, Tsuyoshi| |
| Abstract | Some important results on persistence are reviewed. These results concern the behavior of the orbits approaching the boundary. The orbits restrict the flow on the boundary, if one of them approaches more than one invariant set. A typical example is a model for cyclic competition, where the heteroclinic cycle can be the ω-limit set. Thus the persistence can be reduced to some conditions on the boundary flow. |
| Keywords | persistence ordinary differential equation dynamical system |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2005-02-28 |
| Volume | volume10 |
| Issue | issue1 |
| Start Page | 13 |
| End Page | 21 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313932 |
| JaLCDOI | 10.18926/fest/11481 |
|---|---|
| FullText URL | 010_009_011.pdf |
| Author | Kajiwara, Tsuyoshi| Sasaki, Toru| |
| Abstract | An elementary proof of permanence for a simple mathematical model proposed by Nowak and Bangham. In many papers, permanence property is proved by theorems established by the general theory of dynamical system. In this paper, we present an elementary proof only using differential inequalities and the theory of linear differential equations with constant coefficients. |
| Keywords | Permanence dynamical system pathogen |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2005-02-28 |
| Volume | volume10 |
| Issue | issue1 |
| Start Page | 9 |
| End Page | 11 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313596 |
| JaLCDOI | 10.18926/fest/11469 |
|---|---|
| Title Alternative | Measurement of thermal conductivity in soils and application of de Vries model |
| FullText URL | 009_117_120.pdf |
| Author | Moroizumi, Toshitsugu| Sato, Yuichi| Sato, Koichi| Sasaki, Choichi| |
| Abstract | Thermal conductivity of soil samples were measured using a twin transient-state cylindrical-probe method. The system of measurement consists of DC power supply, data logger, personal computer, 100cc soil sample, reference material sample, and two heat probes. The typical results were as follows: (1) Thermal conductivity of soils increased according to an increase of soil water content. (2) The thermal conductivity of Toyoura sand was larger than one of Kuroboku soil. (3) The thermal conductivity estimated by de Vries model had good agreement with the measured value. |
| Keywords | Thermal conductivity Twin transient-state cylindrical-probe method de Vries model Volumetric water content |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 117 |
| End Page | 120 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313616 |
| JaLCDOI | 10.18926/fest/11466 |
|---|---|
| FullText URL | 009_099_110.pdf |
| Author | Dewan A.M.| Nishigaki, Makoto| Komatsu, Mitsuru| |
| Abstract | Dhaka city, the capital of Bangladesh and home for more than 10 million people, has been affected by seasonal flooding almost in every year, however, the situation aggravates depending on rainfall and surrounding river waters. The aim of this paper is to delineate the flood extent in Dhaka city using digital elevation model (DEM), an integral part of geographic information system. Catastrophic floods of the 1988 and 1998 events are taken into consideration. Hydro-meteorological assessment of these events revealed that the 1988 flood was severe due to the lack of flood protection in the city together with transboundary flow of the major rivers while the 1998 flood was become deluge due to incessant monsoonal downpour along with early peaked of the river water levels. The 1998 event has done colossal damage in the city compare to the 1988 event. Flood extent estimation showed that DEM data is very precious to model inundation in the city, however, in order to be spatially explicit flood model, high resolution DEM is necessary. Finally, flood management issues are reviewed and found that combination of structural and nonstructural measures are necessary to help reducing flood induced losses and damage in the city. |
| Keywords | Dhaka City Floods Digital Elevation Model 1998 and 1988 Floods |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 99 |
| End Page | 110 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313678 |
| JaLCDOI | 10.18926/fest/11455 |
|---|---|
| FullText URL | 009_045_051.pdf |
| Author | Iuchi Takuma| Kajiwara, Tsuyoshi| |
| Abstract | 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. |
| Keywords | HIV Mathematical model Stability Liapunov function |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 45 |
| End Page | 51 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313809 |
| JaLCDOI | 10.18926/fest/11453 |
|---|---|
| FullText URL | 009_037_044.pdf |
| Author | Sung Jimin| Tanaka, Yutaka| |
| Abstract | 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. |
| Keywords | Cox regression Influence function Local influence Influential Subsets Cox-Snell residuals Martingale residual Deviance residual |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 37 |
| End Page | 44 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313595 |
| JaLCDOI | 10.18926/fest/11448 |
|---|---|
| FullText URL | 009_009_017.pdf |
| Author | Setiawan Agus| Tarumi, Tomoyuki| |
| Abstract | 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. |
| Keywords | Auxiliary data Population density Sample survey Small area estimation WinBUGS |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2004-02-27 |
| Volume | volume9 |
| Issue | issue1 |
| Start Page | 9 |
| End Page | 17 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313784 |
| JaLCDOI | 10.18926/fest/11439 |
|---|---|
| FullText URL | 012_071_076.pdf |
| Author | Chen W.| Yoshida R.| Kawara, Osami| |
| Abstract | The Asahi River Dam reservoir is one of the important fresh water resources in Okayama, Japan, and its eutrophication has been noted since the 1980s. Therefore, aeration has been applied to control the growth of phytoplankton. In this study, we discussed the effect of aeration and water-intake depth on the water quality distribution in the reservoir, based on numerical simulation and observation. The principal conclusions were as follows:(1) The numerical simulation models applied here reproduced observations fairly well. (2) Water intake from the surfacce layer reduced the concentration of chlorophyll a in the surface layers. Water intake from the middle or bottom layer improved the deficit of dissolved oxygen in the bottom layers. (3) Aeration together with water intake from the middle or bottom layer improved the deficit of dissolved oxygen in the bottom layers. |
| Keywords | the Asahi River Dam Reservoir numerical simulation eutrophication water intake depth dissolved oxygen chlorophylla |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 71 |
| End Page | 76 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002314056 |
| JaLCDOI | 10.18926/fest/11436 |
|---|---|
| FullText URL | 012_063_070.pdf |
| Author | Saif Eideen S. A.| Taniguchi, Takeo| |
| Abstract | 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. |
| Keywords | fiber reinforced concrete composite materials homogenization periodicity finite element |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 63 |
| End Page | 70 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313536 |
| JaLCDOI | 10.18926/fest/11435 |
|---|---|
| FullText URL | 011_065_074.pdf |
| Author | Dincsoy Enver Erdinc| Ichiminami, Fumikazu| |
| Abstract | Regional development and regional planning subjects are very closely linked with the development projects in Turkey as much as in the world. The main applications and studies are usually based on the elimination of disparities among regions. Within this framework, this study has firstly aimed to set out the regional development objectives in Turkey. Secondly, we tried to find out the effect of new regional approaches on Turkish regional structure. Hence, as an approach different from other studies, we focused on NUTS (Nomenclature of Territorial Units for Statistics) regions instead of geographical units (regions) studies. In the following parts of the study, thirdly, the efforts of Turkey about the regional development have been discussed and assessed by using Neoclassic Growth Model in terms of per capita income distributions for new region groups. To compare the results of analysis among regional units, the most important development projects for Turkey were also taken as a different approach unlike other sudies. Previous studies based on geographic regions showed that the basic tendency of per capita income distribution is 'Divergence' unlike expected 'Convergence' in Turkey, but in our study, we found more optimistic results for Turkey, in which per capita income distributions have a tendency to converge after 1997. |
| Keywords | Regional Development Turkey NUTS Regional Development Projects Convergence |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2006-03-15 |
| Volume | volume11 |
| Issue | issue1 |
| Start Page | 65 |
| End Page | 74 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002314049 |
| JaLCDOI | 10.18926/fest/11431 |
|---|---|
| FullText URL | 011_051_055.pdf |
| Author | Nishigaki, Makoto| Komatsu, Mitsuru| Akudago John Apambilla| Shinshi Yoshihide| Kawakami Kenji| Kumamaru Koji| |
| Abstract | A laboratory validation of a proposed new method of determining the in-situ effective porosity of unsaturated soils was carried out on unsaturated river sand. The proposed method consists of boring a small diameter hole into the soil and inserting an Amplitude Domain Reflectometry (ADR) probe at the bottom part of the hole. Water is supplied into the hole till saturation and later de-saturated. The water content with time is determined from the ADR probe voltage potential readings. The effective porosity is determined from the difference between the saturated and de-saturated water contents. However, in the laboratory, the water is supplied through the top and bottom parts of the sample. From the experiments the obtained effective porosity ranged from 0.28 to 0.29 for wetting from the top with an average of 0.287 and 0.29 to 0.30 for wetting from the bottom with an average of 0.293. The determined effective porosity ranged from 71.7-73.3% of the real initial porosity of 0.40 of the river sand. The maximum attained degree of saturation during the experiment was 91%. The results indicated that the method will be suitable and useful in determining the effective porosity of medium grained unsaturated soils. |
| Keywords | Underground dam Effective porosity Storage capacity Freshwater development |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2006-03-15 |
| Volume | volume11 |
| Issue | issue1 |
| Start Page | 51 |
| End Page | 55 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313335 |
| JaLCDOI | 10.18926/fest/11430 |
|---|---|
| FullText URL | 011_043_049.pdf |
| Author | Saif Eldeen S. A.| Taniguchi, Takeo| |
| Abstract | The simulation of mechanical bahavior of steel fiber reinforced concrete SFRC is introduced utilizing the homogenization method. The random distribution of fibers has been converted to a periodic distribution. Using the periodicity assumption, the boundary conditions for the unit cell are derived. The homogenized stiffness matrix is determined in elastic and plastic range. A numerical example to study the effect of the volume fraction of fibers is introduced. |
| Keywords | fiber reinforced concrete composite materials homogenization periodicity finite element |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2006-03-15 |
| Volume | volume11 |
| Issue | issue1 |
| Start Page | 43 |
| End Page | 49 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002313548 |
| JaLCDOI | 10.18926/fest/11426 |
|---|---|
| Title Alternative | Hydrodynamic and structural simulation by a particle approach |
| FullText URL | 011_019_026.pdf |
| Author | Morita, Toshimasa| Kajiwara, Tsuyoshi| |
| Abstract | This paper is a research report concerning the hydrodynamic simulation and the structural simulation by a particle approach. The proposal particle method model is introduced in this report, and the calculation example by the calculation code which uses the proposal model is shown. The high possibility of the particle method is shown by calculation examples which is difficult to solve by FDM and FEM. It is shown by caliculation examples of both the hydrodynamic and the structure analysis problems that the proposal model enables us to treat the fluid and the structure in a unified way. |
| Keywords | Particle Simulation Hydrodynamic analysis Structural analysis |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2006-03-15 |
| Volume | volume11 |
| Issue | issue1 |
| Start Page | 19 |
| End Page | 26 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313653 |
| JaLCDOI | 10.18926/fest/11425 |
|---|---|
| Title Alternative | A mathematical model of Plasmodium falciparum transmission incorporating drug resistance: Simulations of the Solomon Islands situation |
| FullText URL | 012_019_027.pdf |
| Author | Chen, Tiantian| Nishina, Tomohiko| Hisakane, Naoto| Ishikawa, Hirofumi| |
| Abstract | The Solomon Islands are known as a high endemic region of malaria. The resistance of Plasmodium falciparum to chloroquine has been confirmed since 1980 in the Solomon Islands, and the spread of chloroquine resistance is a big hurdle to malaria control. We have constructured the model for P. falciparum making allowance of chloroquine resistance. We distinguish the infection of resistance strains from that of sensitive strains in both the human and the vector populations. Since the overall parasite rate and the parasite rate of gametocytes for P. falciparum are strongly dependent on age, the human population is divided into 7 age groups in the model. The epidemiological parameters are determined by malariological survey in northeastern Guadalcanal (Ishii et al.) and the sporozoite rate in vector population is assumed as 0.1% based on the entomological study (Harada et al.) Our study aims at estimating the effect of mass drug administration under the presence of drug-resistance and also analyzing the escalation of drug-resistance through the transmission model for P. falciparum which can deal with chloroquine resistance. |
| Keywords | Solomon Islands Plasmodium falciparum drug resistance model |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2007-03-15 |
| Volume | volume12 |
| Issue | issue1 |
| Start Page | 19 |
| End Page | 27 |
| ISSN | 1341-9099 |
| language | Japanese |
| File Version | publisher |
| NAID | 120002313858 |
| JaLCDOI | 10.18926/fest/11424 |
|---|---|
| FullText URL | 011_009_014.pdf |
| Author | Nishina Tomohiko| Tian Tian Chen| Fujita Kazutoshi| Ishikawa, Hirofumi| |
| Abstract | The red fox (Vulpes vulepes) and the vole ( Clethrionomys refocanus) are principal hosts of Echinococcus multilocularis in Hokkaido, Japan. How protoscoleces increases in voles and the level of immunity in foxes remain unknown because of the lack of survey data, so that it is important to clarify these mecahnisms in order to develop control strategies against E. multilocularis. In this study, the growth of protoscoleces in the infected voles was approximated as the logistic curve, the level of immunity in the fox was assumed to depend on the experience of the infection with E. multilocularis, and the worm burden in the fox was assumed to be governed by the amount of protoscoleces in the vole. Our model showed that the population densities of the hosts and the level of immunity influenced the prevalence of the E. multilocularis. |
| Keywords | Echinococcus multilocularis protoscoleces immunity worm burden stochastic model |
| Publication Title | 岡山大学環境理工学部研究報告 |
| Published Date | 2006-03-15 |
| Volume | volume11 |
| Issue | issue1 |
| Start Page | 9 |
| End Page | 14 |
| ISSN | 1341-9099 |
| language | English |
| File Version | publisher |
| NAID | 120002314034 |
