学位授与大学：京都大学 ; 取得学位: 博士(工学) ; 学位授与年月日: 2007-09-25 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2846号 ; 請求記号: 新制/工/1419 ; 整理番号: 25531 / 1.1.1 Disaster planning and management: an overview With the rapid economic development and urbanization, the cities are growing fast. Throughout the world it is common to observe that large cities and urban agglomerations along with a wide range of opportunities also bring a variety of safety risk. Cities, as those grow bigger and bigger and become more complex, generally become increasingly vulnerable to hazard, both natural and man-made (Misra, 2004). Many cities are located on seismically active zones, near active volcanoes and on areas prone to cyclones and floods and possibilities of damage by these hazards have increased significantly. Due to the lack of proper awareness and preparedness to disasters, the number of casualties affected and economic losses caused by natural disasters have been increasing over recent decades (EM-DAT, 2004). For example, the Tangshan earthquake (July 28, 1976) in China devastated the whole municipality, and killed 242, 000 people with millions of people homeless (Liu, 1985). The Indian Ocean earthquake (December 26, 2004) and subsequent tsunamis caused a total of 229, 866 people lost, including 186, 983 dead and 42, 883 missing (United Nations, 2005). Now, most of the countries have taken various countermeasures to reduce the losses due to disasters. Safety, risk management and disaster preparedness, are now becoming very import aspects of city management in Japan. In the wake of accelerated urban growth and emergence of strong market forces, local area needs and priorities in Japan changed and so was the perception of day to day risks and security from disasters (Misra, 2004). The structural countermeasures are effective in saving people’s lives and properties especially from the small-scale low-impact disasters. While for the low-frequency high-impact disasters, these measures probably cause more losses especially when the risks level greatly exceeds the resilience capacity of infrastructure. That was exactly what happened in the Great Hanshin-Awaji earthquake (January 17, 1995) in Japan (The Asashi Simbun, 1996). The earthquake also taught people that the impact of a low-frequency high-impact disaster (catastrophic disaster) may exceed the present capacity of the public rescue and relief services. In most of the similar cases of catastrophic disasters, the local governments are found to be not able to provide the sufficient services to the citizens in the time of disaster. Though various types of national or international assistances from outside of the suffered region may be available, such as those provided by NGOs, NPOs and INGOs, that kind of external assistance is not at all sufficient, particularly for rescue, relief and recovery. So, it is needed to stress the need for community capacity building. Both communities and local authorities should be empowered to manage and reduce disaster risk by having access to the necessary information, resources and authority to implement actions for disaster risk reduction (Hyogo Framework, 2005). If the local government is only the decision-maker in such cases, they may inevitablely be in bias due to the lack of local knowledge even with the experts’ help. The local government should also learn from the local residents. On the other hand, the individual citizens and the local community should have sufficient professional advice for preparation in advance to cope up with the sudden disaster shocks (The Asashi Simbun, 1996). Often due to the lack of professional knowledge, the individual citizens and the local community fail to find their best way to get prepared for disaster risks. They also need to learn from the local government, experts, or NGO/NPOs. This kind of two-way risk communications are often called “social co-learning” (Okada, 2005). Japan, realizing the need for promotion of ‘bottom-up’ planning and closer involvement of the civil society in urban development, also brought in appropriate changes in its Urban Planning Law in the 1992 and made it mandatory for the local governments to adopt participatory urban planning at the local level (Misra, 2004). After the 1995 Great Hanshin-Awaji earthquake, the local government has started to take the proactive countermeasures in collaboration with the local communities and individual citizens. Institutional changes are also under way, which gradually shifted the conventional type of top-down approach towards the bottom-up approach (multi-stakeholder participatory approach) (Okada et al., 2004). In Japan, self help (“Jijyo” in Japanese) and mutual aid (“Kyojyo” in Japanese) are now more advocated by many policy makers and frequently quoted as keywords for community-based disaster reduction, in the official documents and manuals on disaster planning and management. For example, the Disaster Planning Manual of Kagawa Prefecture (2006) emphasizes the importance of self help, and mutual aid for disaster risk management. Such self-help and mutual-aid activities can enhance the individual citizen’s awareness, and enhance their internal communications with other neighboring individuals and communities. Besides the individuals and the community, disaster volunteers, such as NGOs and NPOs, are also taking more and more important roles in the community’s disaster prevention planning and management. / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第13375号 / 工博第2846号 / 新制||工||1419(附属図書館) / 25531 / UT51-2007-Q776 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 岡田 憲夫, 教授 中川 大, 教授 多々納 裕一 / 学位規則第4条第1項該当

Dans un anneau de polynômes à $n$ indéterminées $A\n=A[y_1\tr y_n]$ à coefficients dans un anneau commutatif unitaire $A$ on dit qu'un polynôme $p=p(y_1\tr y_n)$ est une variable ou $A$-variable s'il existe un ($A$-)automorphisme $\alpha$ de $A\n$ tel que $p=\alpha(y_1)$. Dans cette thèse, on donne une construction assez générale de variables de $A\n$ par conjugaison d'automorphismes de $A\n$ avec des automorphismes de $(\Quot A)\n$. On définit les variables résiduelles qui désigne des polynômes qui sont des variables modulo $\Max$ pour tout idéal ma\-xi\-mal $\Max$ de $A$, en particulier, lorsque $A=\C\x=\C[x_1\tr x_k]$, on parle de variables $\xb$-résiduelles. Bien entendu les variables sont des variables résiduelles mais la réciproque est-elle vraie? On montre, grâce à un résultat de Daigle et Freudenburg, que les variables $\xb$-résiduelles de $\C\x[y,z]$ sont bien des $\xb$-variables. Les variables interviennent également dans les problèmes d'hyperplans plongés d'Abhyankar-Sathaye; un polynôme $p$ de $A\n$ est un ($A$-)hyperplan si le quotient de $A\n$ par l'idéal principal engendré par $p$, $(p)$ est isomorphe à $A^{[n-1]}$. Les variables sont des hyperplans et on étudie là encore la réciproque. Dans l'article co-écrit avec M.M. Kaliman et Zaidenberg qui fait partie de cette thèse on étudie les hyperplans de $\C[x,y,z,u]$ de la forme $p=f(x,y)u+g(x,y,z)$. À un changement des variables $x$ et $y$ près on montre que ces hyperplans sont aussi des variables $x$-résiduelles et partant de là on montre que ce sont des $x-$plans (i.e. $A$-plans où $A=\C[x]$) de $\Cx[y,z,u]$ et même qu'il existe un automorphisme $\alpha$ de $A[y,z,u,v]$ tel que $\alpha((p,v))=(y,v)$. Dans certains cas, par exemple lorsque $g$ est de degré un en $z$, on parvient à prouver que ce sont des $x$-variables. On donne aussi une généralisation d'un théorème de Wright en montrant qu'un $x$-plan de la forme $f(x,y,z)u^n+g(x,y,z)$ où $n\geq 2$ est une $x$-variable. Cependant le problème reste irrésolu concernant, par exemple, le polynôme $y+x[xz+y(yu+z^2)]$ qui, bien qu'étant un $x$-plan et une variable $x$-résiduelle ne semble pas être une $x$-variable.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21327号 / 理博第4423号 / 新制||理||1635(附属図書館) / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)准教授 COLLINS,Benoit Vincent Pierre, 教授 泉 正己, 教授 日野 正訓 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM