检索结果-南通市图书馆

Multi-parameter Tikhonov Regularization—An Augmented Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

数学年刊：B辑英文版 2014年第3期35卷 383-398页

作者： Kazufumi ITO Bangti JIN tomoya TAKEUCHI Center for Research in Scientific Computation & Department of Mathematics North Carolina State University Department of Mathematics University of California Riverside 900 University Ave.Riverside CA92521 USA. Collaborative Research Center for Innovative Mathematical Modelling Institute of Industrial ScienceThe University of Tokyo 4-6-1-Cw601 Komaba Meguro-ku Tokyo 153-8505 Japan.

We study multi-parameter regularization(multiple penalties) for solving linear inverse problems to promote simultaneously distinct features of the sought-for objects. We revisit a balancing principle for choosing regularization parameters from the viewpoint of augmented Tikhonov regularization, and derive a new parameter choice strategy called the balanced discrepancy principle. A priori and a posteriori error estimates are provided to theoretically justify the principles, and numerical algorithms for efficiently implementing the principles are also provided. Numerical results on deblurring are presented to illustrate the feasibility of the balanced discrepancy principle.

关键词： Tikhonov正则化增强方法平衡原则后验误差估计正则化参数选择策略数值算法数值结果

Point Sources Identification Problems for Heat Equations

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2009年第5期5卷 897-913页

作者： Leevan Ling tomoya Takeuchi Department of Mathematics Hong Kong Baptist UniversityKowloon TongHong Kong Graduate School of Mathematical Sciences University of Tokyo3-8-1 KomabaMeguroTokyo153-8914Japan

We considered the point source identification problems for heat equations from noisy observation data taken at the minimum number of spatially fixed measurement *** aim to identify the unknown number of sources and their locations along with their *** our previous work,we proved that minimum measurement points needed under the noise-free *** this paper,we extend the proof to cover the noisy cases over a border class of source *** show that if the regularization parameter is chosen properly,the problem can be transformed into a poles identification problem.A reconstruction scheme is proposed on the basis of the developed theoretical *** demonstrations in 2D and 3D conclude the paper.

关键词： Point source source identification heat equations noisy data convergence

Stall Inception Process and Prospects for Active Hub-Flap Control in Three-Stage Axial Flow Compressor

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2008年第4期17卷 324-330页

作者： tomoya OKADA Atsushi KAWAJIRI Yutaka OHTA Eisuke OUTA Graduate school of Science and Engineering Waseda University Department of Applied Mechanics and Aerospace Engineering Waseda University

使用活跃中心拍动的可能性控制方法，它是为一台单个阶段的压缩机的一个证明旋转货摊控制方法，到 3 阶段轴的压缩机试验性地被讨论，在复杂旋转货摊开始进程被观察的地方。研究压缩机是 3 阶段并且能为转子片和定子翼改变 stagger 角... 详细信息

使用活跃中心拍动的可能性控制方法，它是为一台单个阶段的压缩机的一个证明旋转货摊控制方法，到 3 阶段轴的压缩机试验性地被讨论，在复杂旋转货摊开始进程被观察的地方。研究压缩机是 3 阶段并且能为转子片和定子翼改变 stagger 角度背景。十六个转子片 / 定子翼配置模式被变化测试蹒跚为定子翼的角度。由表面压力变化的测量，货摊开始进程被调查，测量压力变化数据为旋转货摊被用作一个预兆的信号。货摊察觉系统在一台单个阶段的压缩机用于活跃中心拍动控制的试验性的结果表演能有用地与一个更复杂的货摊开始过程在一台 3 阶段压缩机被用于那。

关键词：压缩机方法旋转式喷灌器研究

Time-space Viewpoint Planning for Guard Robot with Chance Constraint

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2019年第4期16卷 475-490页

作者： Igi Ardiyanto Jun miura Department of Electrical Engineering and Information Technology Universitas Gadjah Mada No. 2 Jl. Grafika Yogyakarta 55281 Indonesia Department of Computer Science and Engineering Toyohashi University of Technology 1-1 Hibarigaoka Tenpaku-cho Toyohashi Aichi 441-8580 Japan

This paper presents a novel movement planning algorithm for a guard robot in an indoor environment, imitating the job of human security. A movement planner is employed by the guard robot to continuously observe a certain person. This problem can be distinguished from the person following problem which continuously follows the object. Instead, the movement planner aims to reduce the movement and the energy while keeping the target person under its visibility. The proposed algorithm exploits the topological features of the environment to obtain a set of viewpoint candidates, and it is then optimized by a cost-based set covering problem. Both the robot and the target person are modeled using geodesic motion model which considers the environment shape. Subsequently, a particle model-based planner is employed, considering the chance constraints over the robot visibility, to choose an optimal action for the robot. Simulation results using 3D simulator and experiments on a real environment are provided to show the feasibility and effectiveness of our algorithm.

关键词： Guard robot viewpoint planning state-time space uncertainty topology chance-constraint

Effects of uniaxial compressive strain on the electronic- transport properties of zigzag carbon nanotubes

在线全文

学校读者我要写书评

暂无评论

Nano Research 2016年第5期9卷 1267-1275页

作者： Masato Ohnishi Ken Suzuki Hideo miura Fracture and Reliability Research Institute Graduate School of Engineering Tohoku University Sendai 980-8579 Japan

Recently, substantial attention has been paid to the strain sensitivity of the carbon nanotubes＇（CNTs＇） electronic properties. In this study, the relationships between the geometric structures and electronic states of zigzag CNTs under uniaxial compressive strain were investigated. We found that different factors dominate the electronic states of zigzag CNTs depending on the strain regions： the initial stage of the strain loading, which lasts until column-buckling deformation begins, and the strain regions corresponding to column- and shell-buckling deformations. Because shell-buckling deformation significantly increases the re-orbital angle, the angle between the π orbital axis vectors of adjacent atoms, strong localization of the density of states （LDOS） occurs in the buckled area. We also analyzed the current able to pass through deformed CNTs using a tight-binding-based Green＇s function approach and determined that the current can be significantly suppressed by applying uniaxial compressive strain. Our method of predicting the electronic state of a deformed CNT based on the π-orbital angle is expected to be useful for predicting the electronic properties of CNT-based electronic devices and sensors.

关键词： carbon nanotube strain buckling deformation Green's function method electronic-transport property

Effect of Stacking Fault Energy on the Grain Structure Evolution of FCC Metals During Friction Stir Welding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2020年第7期33卷 1001-1012页

作者： Xiaochao Liu Yufeng Sun tomoya Nagira Kohsaku Ushioda Hidetoshi Fujii Joining and Welding Research Institute Osaka University11-1 MihogaokaIbarakiOsaka 567-0047Japan School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'an 710072China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

The effect of stacking fault energy(SFE) on the grain structure evolution of face-centered cubic metals during friction stir welding was investigated by using pure aluminum,pure copper and Cu-30 Zn alloy as experiment *** "stop action" and rapid cooling were employed to "freeze" the microstructure of the flowing materials around the *** materials were used to show the streamline of the material *** microstructures of the three materials at different welding stages were contrastively studied by the electron backscatter diffraction *** results show that at the material flow stage,as the SFE decreases,the grain structure evolution changes from the continuous dynamic recrystallization to discontinuous dynamic recrystallization,and further to the dynamic equilibrium between the annealing twinning due to thermally activated grain boundary migration and the twin destruction during the plastic *** to different grain structure evolution mechanisms,the grain structure at the end of the material flow is greatly *** in copper,a lot of dislocations remain,which gives rise to the static recrystallization occurring during the subsequent cooling stage.

关键词： recrystallization grain welding

Last deglacial relative sea level variations in Antarctica derived from glacial isostatic adjustment modelling

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2013年第6期4卷 623-632页

作者： Jun’ichi Okuno Hideki miura National Institute of Polar Research 10-3 Midori-choTachikawaTokyo 190-8518Japan Research Institute for Global Change Japan Agency for Marine-Earth Science and Technology3173-25 Showa-machiKanazawa-kuYokohama 236-0001Japan

We present relative sea level （RSL） curves in Antarctica derived from glacial isostatic adjustment （GIA）predictions based on the melting scenarios of the Antarctic ice sheet since the Last Glacial Maximum （LGM）given in previous ***,Holocene-age RSL observations obtained at the raised beaches along the coast of Antarctica are shown to be in agreement with the GIA *** differences from previously published ice-loading models regarding the spatial distribution and total mass change of the melted ice are *** models were also derived from GIA modelling; the variations can be attributed to the lack of geological and geographical evidence regarding the history of crustal movement due to ice sheet ***,we summarise the previously published ice load models and demonstrate the RSL curves based on combinations of different ice and earth *** RSL curves calculated by GIA models indicate that the model dependence of both the ice and earth models is significantly large at several sites where RSL observations were *** particular,GIA predictions based on the thin lithospheric thickness show the spatial distributions that are dependent on the melted ice thickness at each *** characteristics result from the short-wavelength deformation of the ***,our predictions strongly suggest that it is possible to find the average ice model despite the use of the different models of lithospheric *** sea level and crustal movement observations,we can deduce the geometry of the post-LGM ice sheets in detail and remove the GIA contribution from the crustal deformation and gravity change observed by space geodetic techniques,such as GPS and GRACE,for the estimation of the Antarctic ice mass change associated with recent global warming.

关键词： Antarctic ice sheet Relative sea level Glacial isostatic adjustment Melting history Lithospheric thickness

Role of autophagy in the pathogenesis of inflammatory bowel disease

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2017年第11期23卷 1944-1953页

作者： tomoya Iida Kei Onodera Hiroshi Nakase Department of Gastroenterology and Hepatology Sapporo Medical University School of MedicineHokkaido 060-8556Japan

Inflammatory bowel disease(IBD) results from a complex series of interactions between susceptibility genes, the environment, and the immune ***, some studies provided strong evidence that the process of autophagy affects several aspects of mucosal immune responses. Autophagy is a cellular stress response that plays key roles in physiological processes, such as innate and adaptive immunity, adaptation to starvation, degradation of aberrant proteins or organelles, antimicrobial defense, and protein secretion. Dysfunctional autophagy is recognized as a contributing factor in many chronic inflammatory diseases, including IBD. Autophagy plays multiple roles in IBD pathogenesis by altering processes that include intracellular bacterial killing, antimicrobial peptide secretion by Paneth cells, goblet cell function, proinflammatory cytokine production by macrophages, antigen presentation by dendritic cells, and the endoplasmic reticulum stress response in enterocytes. Recent studies have identified susceptibility genes involved in autophagy, such as NOD2, ATG16L1, and IRGM, and active research is ongoing all over the world. The aim of this review is a systematic appraisal of the current literature to provide a better understanding of the role of autophagy in the pathogenesis of IBD. Understanding these mechanisms will bring about new strategies for the treatment and prevention of IBD.

关键词： Autophagy Inflammatory bowel disease Genome-wide association study Ulcerative colitis Crohn’s disease

An Energy Regularization for Cauchy Problems of Laplace Equation in Annulus Domain

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2011年第4期9卷 878-896页

作者： Houde Han Leevan Ling tomoya Takeuchi Department of Mathematical Sciences Tsinghua UniversityBeijing 100084China Department of Mathematics Hong Kong Baptist UniversityKowloon TongHong Kong Department of Mathematics North Carolina State UniversityRaleighNorth Carolina 27695-8212USA.

Detecting corrosion by electrical field can be modeled by a Cauchy problem of Laplace equation in annulus domain under the assumption that the thickness of the pipe is relatively small compared with the radius of the *** interior surface of the pipe is inaccessible and the nondestructive detection is solely based on measurements from the outer *** Cauchy problem for an elliptic equation is a typical ill-posed problem whose solution does not depend continuously on the boundary *** this work,we assume that the measurements are available on the whole outer boundary on an annulus *** imposing reasonable assumptions,the theoretical goal here is to derive the stabilities of the Cauchy solutions and an energy regularization *** between the proposed energy regularization method and the Tikhonov regularization with Morozov principle is also given.A novel numerical algorithm is proposed and numerical examples are given.

关键词： Inverse problem stability error bounds Tikhonov regularization method of fundamental solution