岡山大学環境理工学部Acta Medica Okayama1341-90991012005Synthesis of ellagic acid and its 4,4'-di-Ο-alky derivatives from gallic acid111117ENYutakaTakaguchiSadaoTsuboi10.18926/fest/11508Synthesis of ellagic acid and its 4,4'-di-Ο-alkyl derivatives from gallic acid is described. Ellagic acid is prepared by oxidative coupling of gallic acid with ο-chloranil. Functionalized methyl bormogallate underwent Ullmann coupling to give the biphenyl that upon lactonization resulted in the ellagic acid and its alkoxy derivatives.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-909910120051,3-Dibromo-5,5-dimethylhydantoin, a useful reagent for ortho-monobromination of phenols and polyphenols105109ENYutakaTakaguchiSadaoTsuboi10.18926/fest/11506Ortho-monobromination of phenols and polyphenols by 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) is described. A simple addition of commercially available DBDMH to phenols and polyphenols in chloroform at room temperature resulted in a good to excellent yield of corresponding ortho-monobromo derivatives.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005岡山駅周辺の放置自転車の現状とその対策89103ENYosukeToyokiFumikazuIchiminami10.18926/fest/11505In this paper, first it is investigated illegally parked bicycles around the Okayama station, withdrawal, storage and return of them. Second, there will be a questionnaire to understand citizen's consciousness and clarify how they have been grasped present condition. Furthermore, it is aimed that considering how to carry out an efficient activity for reducing number of illegally parked bicycles. The results are concluded as follows. It is much more required to strengthening in the criminal prohibition zone by applying withdrawal activities and regulations. Presumably, first it is required to change storage area in order to increase the rate of returned bicycles. Besides, it will be great improvement in rate of return, if definite proportion of area is confidentially secured on storage area near the Okayama station. Moreover, it was remarkable that a citizen was not known in detail about an illegally parked bicycle. On the other side, recognition of most of the suburbanite of Okayama-shi tends to be impervious and replied to affirm illegally parked bicycle. However, the residents who live an area near to station understood the present condition well, and they disapprove to the illegally parked bicycle. Finally, in order to improve present condition, to prevent completely and to decrease the number of illegally parked bicycles publicity work is required.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005Sustainable Groundwater Exploitation under Natural Conditions in Southwest Ghana8388ENMakotoNishigaki10.18926/fest/11502Groundwater 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/sｋu 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.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005Rapid Impact Assessment Matrix (RIAM) - An Analytical Tool in the Prioritization of Water Resources Management Problems in Ghana7581ENPhilipGyau-BoakyeMakotoNishigaki10.18926/fest/11501The rapid impact assessment (RIAM), which was developed in Denmark, is a new tool for the execution of environmental impact assessments. RIAM is quite flexible, transparent and leaves a permanent record, which can be independently checked, validated or updated. RIAM has successfully been used to prioritize water resources management problems in Ghana in the order of which problems call for the most urgent attention. The priority list was easily validated and accepted to be the true reflection of the situation at a national workshop in which experts and representatives from water agencies, donor agencies, university faculties and departments, research institutes, private institutions and organizations including Non Governmental Organizations (NGOs) participated. The study has shown that RIAM, which can also be used in a developing country like Ghana, is a very useful tool in such prioritization process as has been applied in this exercise.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005Evaluating Flood Damage using GIS and RADARSAT data-A case of the 1998 Catastrophe in Greater Dhaka, Bangladesh6774ENMakotoNishigaki10.18926/fest/11499The objective of this paper is to delineate flood prone areas and estimate damage in Greater Dhaka during the 1998 catastrophic flood using an integrated approach of GIS and remote sensing. Time series RADARSAT SAR data is acquired and used to demarcate flood boundaries for the 1998 flood event. This was accomplished by thresholding linear SAR imageries. Flood estimation demonstrated that flood areas steadily increased from early July 1998 and peaked on 25 August 1998 inundating 53% lands due to heavy monsoonal downpour and discharge from upstream points. Different thematic layers were combined with a derived flood map in order to assess flood damage for the same event. Flood damage analysis revealed that substantial damage has occurred in Greater Dhaka during the 1998 flood.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005Remote Sensing of 1998 and 2000 Floods in Greater Dhaka, Bangladesh: Experiences from Catastrophic and Normal events5765ENMakotoNishigaki10.18926/fest/11496This paper is an attempt to develop a series of maps that precisely depict flood prone areas in Greater Dhaka, Bangladesh using remote sensing techniques. Multi-temporal RADARSAT SAR data were acquired and employed to delineate open water flood boundary during the floods of 1998 and 2000. Using a threshold algorithm, SAR data is segregated into water and non-water areas. The empirical threshold value was obtained by using visual interpretation technique, local knowledge of the study site and by deriving corresponding pixel values to land/water from each image. The result demonstrated that 53 percent of the study area was heavily inundated in 1998 flood which is the largest submerged area during a catastrophic scenario. In contrast, 35.32 percent area was flooded during the year 2000 which represents the area under water for a normal event. Using the reference data acquired from field visit, derived flood maps were further validated. Moderate accuracy is obtained for all flood maps, however, July 1998 image attained the highest overall accuracy (86%) in the dataset. The derived flood maps are expected to be useful to mitigate losses of lives and property from river water flooding in Greater Dhaka. Furthermore, this information would be worthwhile to develop an efficient flood disaster management system.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005コレスポンデンス分析における変数選択規準の検討4956ENYuichiMoriXiao DongDuMasayaIizuka10.18926/fest/11489Ordinary 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).No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005分割表データにおけるApriori Alogrihtmを利用した変数選択手法4147ENManabuOhnoTomoyukiTarumi10.18926/fest/11486We proposed a new applied method for induction of variable selection on contingency table. This method is the application of Apriori algorithm on variable selection of contigency table with iteraction. We assume that variables are dichotomous variable. We confirm that can be select variable, when minimun support is low level by using AIC on variable selection criterion.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005Computation of the Grothendieck-Witt ring of nonsingular Hermitian forms with positioning map2939EN10.18926/fest/11485The 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.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005Computational Analysis of Currents Generated in Kojima Lake Based on Updated Topographical Data2328ENMasajiWatanabe10.18926/fest/11484Topographical 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.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005力学系のパーシステンスについて（レビュー）1321ENToruSasakiTsuyoshiKajiwara10.18926/fest/11483Some 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.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005A permanence theorem for a mathematical model for dynamics of pathogens and cells in vivo using elementary methods911ENTsuyoshiKajiwaraToruSasaki10.18926/fest/11481An 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.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341-90991012005Linear and Differential Cryptanalysis of SHA-25617ENHirofumiIshikawa10.18926/fest/11479The 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.No potential conflict of interest relevant to this article was reported.