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Asymmetrical sequential excavation is common in shallow tunnel engineering, especially for large-span tunnels. Owing to the lack of necessary conformal mappings, existing complex variable solutions on shallow tunnelling are only suitable…

Numerical Analysis · Mathematics 2025-01-17 Luo-bin Lin , Fu-quan Chen , Change-jie Zheng , Shang-shun Lin

Contour integral methods for nonlinear eigenvalue problems seek to compute a subset of the spectrum in a bounded region of the complex plane. We briefly survey this class of algorithms, establishing a relationship to system realization…

Numerical Analysis · Mathematics 2021-01-01 Michael C. Brennan , Mark Embree , Serkan Gugercin

Inverse problems of recovering the coefficients of Sturm-Liouville problems with the eigenvalue parameter linearly contained in one of the boundary conditions are studied: (1) from the sequences of eigenvalues and norming constants; (2)…

Spectral Theory · Mathematics 2008-03-06 Namig J. Guliyev

A type of parallel augmented subspace scheme for eigenvalue problems is proposed by using coarse space in the multigrid method. With the help of coarse space in multigrid method, solving the eigenvalue problem in the finest space is…

Numerical Analysis · Mathematics 2020-08-19 Fei Xu , Hehu Xie , Ning Zhang

This paper introduces a fast and numerically stable algorithm for the solution of fourth-order linear boundary value problems on an interval. This type of equation arises in a variety of settings in physics and signal processing. Our method…

Numerical Analysis · Computer Science 2020-01-13 William Leeb , Vladimir Rokhlin

The present paper deals with the discrete inverse problem of reconstructing binary matrices from their row and column sums under additional constraints on the number and pattern of entries in specified minors. While the classical…

Data Structures and Algorithms · Computer Science 2017-02-22 Andreas Alpers , Peter Gritzmann

This paper presents a new and straightforward procedure for solving bilinear quadratic optimal control problem. In this method, first the original optimal control problem is transformed into a nonlinear twopoint boundary value problem…

Optimization and Control · Mathematics 2012-02-09 Hamidreza Ramezanpour , Saeed Setayeshi , Hossein Arabalibeik , Amin Jajarmi

In this paper, we consider the travel time tomography problem for conformal metrics on a bounded domain, which seeks to determine the conformal factor of the metric from the lengths of geodesics joining boundary points. We establish forward…

Differential Geometry · Mathematics 2024-05-28 Ashwin Tarikere , Hanming Zhou

In this work we present Haar wavelet collocation method and solve the following class of system of Lane-Emden equation defined as \begin{eqnarray*} -(t^{k_1} y'(t))'=t^{-\omega_1} f_1(t,y(t),z(t)),\\ -(t^{k_2} z'(t))'=t^{-\omega_2}…

Numerical Analysis · Mathematics 2019-12-04 Amit K. Verma , Narendra Kumar , Diksha Tiwari

It is well known that the usual mixed method for solving the biharmonic eigenvalue problem by decomposing the operator into two Laplacians may generate spurious eigenvalues on non-convex domains. To overcome this difficulty, we adopt a…

Numerical Analysis · Mathematics 2021-07-27 Baiju Zhang , Hengguang Li , Zhimin Zhang

Bilevel optimisation is used in inverse imaging problems for hyperparameter learning/identification and experimental design, for instance, to find optimal regularisation parameters and forward operators. However, computationally, the…

Optimization and Control · Mathematics 2025-08-06 Ensio Suonperä , Tuomo Valkonen

The invariant theory of Killing tensors (ITKT) is extended by introducing the new concepts of covariants and joint invariants of (product) vector spaces of Killing tensors defined in pseudo-Riemannian spaces of constant curvature. The…

Mathematical Physics · Physics 2015-06-26 Roman G. Smirnov , Jin Yue

The inverse potential problem consists in determining the density of the volume potential from measurements outside the sources. Its ill-posedness is due both to the non-uniqueness of the solution and to the instability of the solution with…

Numerical Analysis · Mathematics 2025-10-07 P. N. Vabishchevich

This paper deals with numerical methods for reconstruction of inhomogeneous conductivities. We use the concept of Generalized Polarization Tensors, which were introduced in [3], to do reconstruction. Basic resolution and stability analysis…

Analysis of PDEs · Mathematics 2015-10-28 Xiaoping Fang , Youjun Deng

We consider a boundary value problem of the stationary transport equation with the incoming boundary condition in two or three dimensional bounded convex domains. We discuss discontinuity of the solution to the boundary value problem…

Analysis of PDEs · Mathematics 2023-04-05 I-Kun Chen , Daisuke Kawagoe

We propose a new geometric method of IR factorization in sector decomposition. The problem is converted into a set of problems in convex geometry. The latter problems are solved using algorithms in combinatorial geometry. This method…

High Energy Physics - Phenomenology · Physics 2014-11-20 Toshiaki Kaneko , Takahiro Ueda

We present a framework using the Quantized Tensor Train (QTT) decomposition to accurately and efficiently solve volume and boundary integral equations in three dimensions. We describe how the QTT decomposition can be used as a hierarchical…

Numerical Analysis · Mathematics 2016-10-04 Eduardo Corona , Abtin Rahimian , Denis Zorin

We study an inverse problem for a coupled system of semilinear Helmholtz equations where we are interested in reconstructing multiple coefficients in the system from internal data measured in applications such as thermoacoustic imaging. We…

Analysis of PDEs · Mathematics 2023-07-06 Kui Ren , Nathan Soedjak

A method to reconstruct weakly anisotropic inhomogeneous dielectric tensors inside a transparent medium is proposed. The mathematical theory of Integral Geometry is cast into a workable framework which allows the full determination of…

Optics · Physics 2009-11-10 Hanno Hammer , William R. B. Lionheart

This letter announces and summarizes results obtained in arXiv:1111.5051 and considers several natural extensions. The aforementioned paper proposes a procedure to reconstruct coefficients in a second-order, scalar, elliptic equation from…

Analysis of PDEs · Mathematics 2012-03-07 Guillaume Bal , Gunther Uhlmann