The University of Tokyo · 수학
마사히로 야마다 교수의 연구실은 주로 편미분방정식의 해의 안정성과 역문제 해석에 초점을 맞추고 있습니다. 특히 카르레만 추정법을 활용한 고유값 문제, 열전도 및 파동 방정식에서의 초기값 및 경계값 역문제, 그리고 분수계수 열확산 방정식의 계수 재구성 등에 대해 깊이 있는 이론적·수치적 연구를 수행하고 있습니다. 정규화 기법과 경계 제어 이론을 접목한 안정적인 수치 해법 개발이 핵심 연구 방향입니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
methods for applications of the Carleman estimates to estimates of solutions and to inverse problems.
In spite of the fact that product appearance would not seem to bear upon performance, this article provides evidence that the appearance of an industrial product may have an impact on its evaluation. Utilizing a conjoint scaling approach, Mel Yamamoto and David R. Lambert find that industrial product appearance exerts an influence, which in some circumstances exceeds the influence of certain product performance or price attributes. They suggest that attention paid to product aesthetics may have
Let u ( f ) be the solution to a hyperbolic equation in a bounded domain s2 c B ' :and r c~ iJs2 is given.We consider an inverse problem of dete-ingFor a sufficiently large T > 0, we will show the stability estimate of IlfllLqn, by Ilau(f)/anllH,c,,,T:'~tn,. areconstruction formulaof f f" au(f)/an and a Tikhoaov regularization.Our methodology is based on exact boundary cnntrollability and a Voltem integral equation of the first kind with kernel U .
Given the measurement of temperature at a fixed time θ>0 and the measurement of temperature in a subregion of the physical domain, we investigate the simultaneous reconstruction of the initial temperature and heat radiative coefficient in a heat conductive system. The stability of the inverse problem is first established, and then the numerical reconstruction is mainly studied. The reconstruction process is done by Tikhonov regularization with the regularizing terms being the L2-norms of gradien
This paper investigates the numerical computation of a Cauchy problem for Laplace's equation which is a typical ill-posed problem. By using Green's formula, the problem is transformed to a moment problem. For numerical computation of the moment problem, an error estimation and several numerical examples for verification are presented. Necessary and sufficient conditions for the existence of the solution of the Cauchy problems for Laplace's equation in two-dimension are also given.
An inverse problem of determining a zeroth-order coefficient in a one-dimensional fractional diffusion equation of half-order in time is investigated. Under some assumptions on the regularity of the solutions and coefficients, we prove a conditional stability estimate by some additional data. The key is a Carleman estimate, but since we have no Carleman estimates for the fractional diffusion equation, we further take the t-derivative of half-order to obtain the equation where the principal term
We consider a fractional diffusion equation in x ∈ (0, ℓ) where the derivative in time t is of half order in the sense of Caputo and we establish a Carleman estimate. Since the derivatives of non-natural number orders do not satisfy the integration by parts, which is essential for establishing a Carleman estimate, we twice apply the Caputo derivative to convert the original fractional diffusion equation to a system with a usual partial differential operator: . Next we apply the Carleman estimate