Transactions of the Japan Society for Industrial and Applied Mathematics

Online ISSN : 2424-0982
ISSN-L : 0917-2246

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Volume 17, Issue 3

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[title in Japanese]

Article type: Cover
2007 Volume 17 Issue 3 Pages Cover1-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_Cover1

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[title in Japanese]

Article type: Cover
2007 Volume 17 Issue 3 Pages Cover2-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_Cover2

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[title in Japanese]

Article type: Index
2007 Volume 17 Issue 3 Pages Toc1-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_Toc1

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[title in Japanese]

Article type: Appendix
2007 Volume 17 Issue 3 Pages App1-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_App1

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[title in Japanese]

[in Japanese]

Article type: Article
2007 Volume 17 Issue 3 Pages i-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_i

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Isotropy Improvement via Vertex Insertion for 2D Triangular Meshes Generated by DistMesh(Practice)

Yukie Nagai, Kokichi Sugihara, Hiromasa Suzuki

Article type: Article
2007 Volume 17 Issue 3 Pages 195-217
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_195

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Expressing the analysis domains with meshes is common in simulations for fluid dynamics and structural mechanics. The times for calculations and precisions depend on the meshes, so suitable meshes are needed. For phenomena without proper directions of changes, isotropic meshes are preferable. Our aim is improving 2-dimensional triangular mesh isotropy for such simulations. We report inserting vertices into and optimizing meshes generated by an algorithm DistMesh proposed by Persson and Strang [18]. Then we verify the improvements with smoothing after optimization comparing with some results for uniform and adaptive meshes respectively, and show the advantages of our proposed method.

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BiCGSTAB method for solving trapezoidal rule of large ODEs : How we can speed up by reusing of Krylov subspaces

Shinsuke Nakamura, Taketomo Mitsui

Article type: Article
2007 Volume 17 Issue 3 Pages 219-238
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_219

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We are concerned with an efficient numerical solution of linear equations at each time-stepping of the trapezoidal rule applied to a system of linear ordinary differential equations (ODEs) with a constant coefficient matrix of large dimension. We do not assume that the matrix is symmetric. Hence numerical solutions in the family of BiCG method are sought. The present paper describes a method to reuse Krylov subspaces in the BiCGSTAB process over a number of computational steps. It can suppress increase of the memory usage as well as reduce the total number of BiCGSTAB iterations. Numerical examples depict its efficiency.

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The Method of Hierarchical Multi-neighbor Predictors and Residual Orthogonal Transformations and Its Application to Image Compression(Practice, Wavelet Analysi, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Keita Ashizawa, Katsu Yamatani, Naoki Saito

Article type: Article
2007 Volume 17 Issue 3 Pages 239-257
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_239

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We propose new image compression algorithms by predicting each block using an improved gradient estimation at the block boundary followed by applying an orthogonal transformation to the prediction error. Compared to the previously proposed polyharmonic local cosine transform where the DC components of adjacent blocks were used for the gradient estimation, our new methods directly use multiple combinations of the neighboring pixel values to estimate the gradients at block boundary more accurately. Hence, we can improve the prediction of each block using such gradient information. Consequently, we can improve image reconstruction quality and reduce the blocking artifact and aliasing noise.

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A stochastic cellular automaton model on traffic flow, and its phase diagram with an open boundary condition and a critical point(Application, Applied Integrable Systems, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Satoshi Sakai, Katsuhiro Nishinari, Shinji Iida

Article type: Article
2007 Volume 17 Issue 3 Pages 259-275
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_259

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This paper presents a phase diagram with open boundary condition for a stochastic traffic cellular automaton (CA) model which is called S-NFS model. From the matching condition of left and right flows, we get the approximate analytic expressions of the phase transition line. Further the critical point of the phase diagram is obtained by using 2×2-cluster approximation. As a results, we find there are cases where the analytic phase transition line and critical point do not successfully reproduces those of numerical simulations, in contrast with the case of ASEP.

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Analysis on Pedestrian Flow through an Exit by a Cluster Approximation(Application, Applied Integrable Systems, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Daichi Yanagisawa, Katsuhiro Nishinari

Article type: Article
2007 Volume 17 Issue 3 Pages 277-290
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_277

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An average pedestrian flow through an exit is one of the most important index in evaluating pedestrian dynamics. The floor field model, which is a pedestrian dynamics model by using cellular automaton, is extended in this paper by introducing a new parameter in order to take into account a realistic behavior around the exit. We have studied the model by simulations and cluster approximation, and obtained an expression of an average pedestrian flow through the exit. It is found that the effect of exit door width, a wall, and pedestrian's mood of competition or cooperation significantly influence an average flow.

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Numerical and mathematical approach to the support splitting phenomena for some nonlinear diffusion equations(Theory, Scientific Computation and Numerical Analysis, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Kenji Tomoeda, Tatsuyuki Nakaki

Article type: Article
2007 Volume 17 Issue 3 Pages 291-300
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_291

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We consider support splitting phenomena for the porous media equation with the interaction between diffusion and absorption, which describes the flow through the absorbing medium. Here the support means the region occupied by the fluid. In the 1-dimensional case, using the L^1, L^∞ estimates, we have some sufficient conditions under which the support begins to split. In this paper we justify these sufficient conditions from the view point of particular solutions. The extension of the present method to multidimensional problems can be expected.

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On an application of the QMR approach to the Bi-CR method(Theory, Algorithms for Matrix/Eigenvalue Problems and Their Applications, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Satsuki Minami, Tomohiro Sogabe, Masaaki Sugihara, Shao-Liang Zhang

Article type: Article
2007 Volume 17 Issue 3 Pages 301-317
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_301

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The Bi-CG method, a well-known Krylov subspace method for solving non-symmetric linear systems, often shows an irregular convergence behavior in the residual norm. To avoid such a problem, Freund and Nachtigal proposed the QMR method. On the other hand, recently Sogabe et al. proposed the Bi-CR method, and showed experimentally that the Bi-CR method has good convergence. The purpose of this paper is to apply the QMR approach to the Bi-CR method to derive a new method, and to report the results of numerical experiments.

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A preconditioning using sparse direct solvers for approximate coefficient matrices(Note, Algorithms for Matrix/Eigenvalue Problems and Their Applications, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Masayuki Okada, Tetsuya Sakurai, Keita Teranishi

Article type: Article
2007 Volume 17 Issue 3 Pages 319-329
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_319

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We consider a preconditioner for linear systems whose coefficient matrices have many nonzero elements and complex nonzero structure. We seek robust preconditioning using sparse complete factorization of the matrix LU=A obtained from drop-thresholding of the original coefficient matrix A. Due to less nonzero elements in A than A, we expect fewer nonzero elements in the preconditioner L and U than the matrix factor obtained from sparse LU factorization of A. We report the performance of our preconditioner for the sparse matrices that arise from our application including comparison with variants of level-of-fill Incomplete Cholesky preconditioning for complex numbers.

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Finite difference schemes to a mathematical model for tumour invasion(Mathematical Medicine, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Kenji Hayashi, Norikazu Saito

Article type: Article
2007 Volume 17 Issue 3 Pages 331-345
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_331

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The purpose of this paper is to consider finite difference schemes to a mathematical model for tumour invasion. This mathematical model has two important properties. One is conservation of mass, the other is conservation of the positivity. But the standard discretization destroys these properties. In order to overcome this issue, we construct finite difference scheme satisfying these properties by upwind technique.

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Representing Smooth Boundary and Isotropic Tetrahedral Mesh Generation(Practice, Mesh-Generation, Special Issue on "Joint Symposium of JSIAM Activity Groups 2007")

Yukie Nagai, Kokichi Sugihara

Article type: Article
2007 Volume 17 Issue 3 Pages 347-361
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_347

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We propose an algorithm to generate an isotropic tetrahedral mesh whoes domain boundaries are smooth. First we get an isotropic mesh by optimal Delaunay triangulation, then select boundary vertices and move them to new positions for better expression of the domain boundaries as a post porocessing. In the second phase, we get new positions using quadric error metric. To prevent the isotropy from getting worse, we determine each distance between the current position and the new position based on the isotropy of incident elements.

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[title in Japanese]

Article type: Appendix
2007 Volume 17 Issue 3 Pages App2-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_App2

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[title in Japanese]

Article type: Appendix
2007 Volume 17 Issue 3 Pages App3-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_App3

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[title in Japanese]

Article type: Appendix
2007 Volume 17 Issue 3 Pages App4-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_App4

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[title in Japanese]

Article type: Index
2007 Volume 17 Issue 3 Pages Toc2-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_Toc2

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[title in Japanese]

Article type: Cover
2007 Volume 17 Issue 3 Pages Cover3-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_Cover3

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[title in Japanese]

Article type: Cover
2007 Volume 17 Issue 3 Pages Cover4-
Published: September 25, 2007
Released on J-STAGE: April 08, 2017

DOIhttps://doi.org/10.11540/jsiamt.17.3_Cover4

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