检索结果-内蒙古大学图书馆

Generation of phase-gradient optical beams with an iterative algorithm

JOURNAL OF OPTICS 2014年第10期16卷 105701-105701页

作者： Yuan, Zhanzhong Tao, Shaohua Cent South Univ Sch Phys & Elect Changsha 410083 Hunan Peoples R China Cent South Univ Sch Phys & Elect Inst Super Microstruct & Ultrafast Proc Adv Mat Changsha 410083 Hunan Peoples R China

An iterative algorithm based on the Gerchberg-Saxton (GS) algorithm to control both the phase and amplitude of an optical beam in the output plane of a beam-shaping platform is proposed in this paper. In the proposed algorithm, both the phase and the amplitude in the non-zero optical intensity region of a beam in the output plane are constrained, whereas the phase in the other region in the output plane is constraint-free. Thus, both the amplitude and phase distributions in the desired region of the output beam can be controlled with a phase-only hologram. The effectiveness of the algorithm is verified with both the simulations and experiments. The algorithm converges fast and is easy to implement. With this algorithm, we can design various novel optical beams, specifically, the beams with a phase-gradient, which would have extensive applications in areas such as optical trapping.

关键词： iterative algorithm phase-only hologram the beams with phase-gradien GS algorithm optical trapping

来源：评论

学校读者我要写书评

暂无评论

A generalized precision measuring mechanism and efficient signal processing algorithm for the eccentricity of rotary parts

引用

MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2023年 204卷

作者： Xin, Qing-Yuan Pei, Yong-Chen Luo, Meng-Yan Wang, Zhi-Qiong He, Ling Liu, Jian-Yao Wang, Bin Lu, Huiqi Jilin Univ Sch Mech & Aerosp Engn Nanling Campus Changchun 130025 Peoples R China Jilin Univ Coll Automobile Engn Nanling Campus Changchun 130025 Peoples R China Univ Oxford Inst Biomed Engn Dept Engn Sci Oxford OX3 7DQ England

Rotary parts are crucial to transmission equipment. Measuring and analyzing the eccentricity of rotary parts enables the monitoring of vibrations in machinery, ensures smooth operation, and reduces equipment maintenance costs. The accurate measurement and modification of eccentricity are the premise to ensure rotary parts' quality, however, existing measurement methods are computationally inefficient, complex, and expensive to implement, and limited in scope. In this paper, a novel and generalized precision measurement method is proposed to accurately and efficiently evaluate rotary parts' eccentricity parameters, including attitude angle, eccentricity, and eccentric angle. This precision measurement method includes a lever measuring mechanism with a spherical probe and a corresponding efficient signal processing algorithm. The measuring mechanism has a simple structure and can effectively measure arbitrary cross-sections, and its design and optimization principles are investigated and presented thoroughly. The signal processing algorithm can efficiently extract eccentricity parameters of measured cross-sections. This proposed method has proven to overcome the limitations of literacy methods and exhibits generality and anti-interference. Simulation calculation and experimental verification are used to evaluate the effectiveness, computation efficiency, applicability, and repeatability. The proposed method exhibits tremendous potential in a diverse range of applications, such as detecting eccentricity and correcting errors for mechanical measurements, aerospace, equipment manufacturing, and other related fields.

关键词： Contact precision measurement method Lever mechanism with a spherical probe Rotary parts iterative algorithm Eccentricity measurement

来源：评论

学校读者我要写书评

暂无评论

An iterative Method for Split Variational Inclusion Problem and Split Fixed Point Problem for Averaged Mappings

引用

Journal of Applied Mathematics and Physics 2023年第6期11卷 1541-1556页

作者： Kaiwen Wang Yali Zhao Ziru Zhao School of Mathematical Science Bohai University Jinzhou China

In this paper, we use resolvent operator technology to construct a viscosity approximate algorithm to approximate a common solution of split variational inclusion problem and split fixed point problem for an averaged mapping in real Hilbert spaces. Further, we prove that the sequences generated by the proposed iterative method converge strongly to a common solution of split variational inclusion problem and split fixed point problem for averaged mappings which is also the unique solution of the variational inequality problem. The results presented here improve and extend the corresponding results in this area.

关键词： Split Variational Inclusion Problem Split Fixed Point Problem iterative algorithm Averaged Mapping Convergence

来源：评论

学校读者我要写书评

暂无评论

An iterative Interference Alignment algorithm for the General MIMO X Channel

引用

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2019年第3期18卷 1847-1859页

作者： Wei, Yi Lok, Tat-Ming Chinese Univ Hong Kong Dept Informat Engn Hong Kong Peoples R China

Interference alignment (IA) has been shown as an important technique to achieve a linear capacity scaling in wireless communications. However, the IA scheme over finite signaling dimensions for a general multiple-input-multiple-output (MIMO) X channel is still rarely studied. The main challenge of MIMO X channels is that the two sets of conditions for IA, namely the interference nulling conditions and the rank preservation conditions, get coupled. The usual IA methods for the interference channel and the broadcasting channel cannot be applied anymore. In this paper, we show that the rank preservation conditions can be replaced by a group of specific rank conditions, under which the IA problem is simplified. Then, based on this technique, an iterative algorithm of IA is designed for the MIMO X channel. The algorithm is designed with limited signaling dimensions. From the simulation results, we find that the algorithm has good performances even under limited signal-to-noise ratio.

关键词： Beamforming iterative algorithm MIMO systems X channels interference alignment

来源：评论

学校读者我要写书评

暂无评论

Two non-parameter iterative algorithms for identifying strong H-tensors

引用

NUMERICAL algorithmS 2019年第3期81卷 1113-1128页

作者： Xu, Yangyang Zhao, Ruijuan Zheng, Bing Lanzhou Univ Sch Math & Stat Lanzhou 730000 Gansu Peoples R China

The strong H-tensors have important applications in many areas of science and engineering, e.g., the determination of positive definiteness for an even-order homogeneous polynomial form in the real field. In this paper, we propose two iterative algorithms with non-parameter for identifying strong H-tensors, which overcome the drawback of choosing the best value of parameter ? in some existing algorithms given by Li et al. and Liu et al. (J. Comput. Appl. Math., 255, 1-14, 2014 and Comput. Appl. Math. 36, 1623-1635, 2017). Some numerical experiments are performed to illustrate the feasibility and effectiveness of our algorithms.

关键词： Strong H-tensors Non-parameter iterative algorithm Positive definiteness

来源：评论

学校读者我要写书评

暂无评论

Coordinated train rerouting and rescheduling in large infrastructures

引用

Transportation Research Procedia 2023年 72卷 319-326页

作者： Xiajie Yi Grégory Marlière Paola Pellegrini Joaquin Rodriguez Raffaele Pesenti Institut de Recherche Technologique Railenium F-59300 Famars France Univ. Gustave Eiffel IFSTTAR COSYS ESTAS F-59666 Villeneuve d'Ascq France Univ. Gustave Eiffel IFSTTAR COSYS LEOST F-59666 Villeneuve d'Ascq France Universit Ca Foscari Venezia Cannaregio 873 30121 Venice Italy

Railway traffic controllers face the problem that trains are often not operated as planned in timetables due to perturbations such as unexpected, degraded operations, and technical failures. This paper deals with the problem of train rerouting and rescheduling faced by the controllers of different regional railway control centers that must coordinate their decisions to minimize the impact of perturbations over the whole network. We split this real-time railway traffic management problem into two decision levels. At the lower level, the local area controllers, the dispatchers, manage train schedules and routes in their control areas from a microscopic perspective. At the higher level, a coordinator ensures the compatibility of dispatchers' decisions over two or more areas from a macroscopic perspective. To solve our problem, we propose an iterative optimization algorithm. The preliminary experimental results show that the proposed algorithm can reduce the delay propagation.

关键词： real-time traffic management perturbations coordination problem dispatching problem iterative algorithm mathematical programming

来源：评论

学校读者我要写书评

暂无评论

Research on NBA winning percentage prediction

Research on NBA winning percentage prediction

引用

作者： Junyi Li Yuntian Xu Zizheng Xu Luca Pan Shubo Zhang Finance Capital University of Economics and Business Math University of California Irvine High school Shawnigan Lake School High School Vanke Meisha Academy AP Program Beijing National Day School

The National Basketball Association, also known as the NBA, is a professional basketball league composed of 30 professional teams in North America and one of the four major professional sports leagues in the United States. This research delves into predicting winning percentages in NBA games using a data-driven approach. It utilizes three years' worth of comprehensive game data from 30 NBA teams(2014-2016), including actual outcomes and expert predictions. The study aims to acquire valuable teamwork and data research skills while contributing to sports analytics. Data preparation involves cleaning and selecting recent seasons for model training. The prediction model utilizes an iterative algorithm to estimate team strength coefficients based on game results. Though the model shows promise, its accuracy falls slightly short compared to bookies' predictions. The research provides valuable insights for predicting NBA game outcomes and suggests avenues for improving the model's accuracy through additional variables

关键词： Sport performance analysis Winging prediction Predictive model Data preprocessing iterative algorithm

来源：评论

学校读者我要写书评

暂无评论

An algorithm of unordered wavefront propagation in terahertz phase retrieval with dense multiplane data acquisition

COMPUTER OPTICS

引用

COMPUTER OPTICS 2023年第6期47卷 901-+页

作者： Tsiplakova, E. G. Chopard, A. Balbekin, N. S. Smolyanskaya, O. A. Perraud, J. -B. Guillet, J. -P. Mounaix, P. Petrov, N. V. ITMO Univ Kronverksky Pr 49 St Petersburg 197101 Russia Univ Bordeaux IMS Lab UMR CNRS 5218 351 Cours Liberat Batiment A31 F-33405 Talence France Lytid SAS Rue Fontaine 8 F-92120 Montrouge France Optikan SAS Rue Permentade 64 F-33000 Bordeaux France

iterative phase retrieval algorithms from multiple diffraction patterns in the terahertz (THz) frequency range are a promising tool of computational imaging capable of providing high spatial resolution of reconstructed phase images. One of the commonly used algorithms is SBMIR, which employs multiple intensity distributions of the diffraction object wavefield as input data. Com -pared with single-frame methods, the multi-plane approach allows for a faster convergence, but requires time-consuming data acquisition from a receiver positioned at a variety of distances from the object. Previously, we proposed a method for THz data acquisition in a single scan mode, which allows one to quickly obtain an exhaustive set of diffraction distributions. In this paper we evaluate an up-to-date phase retrieval algorithm based on the SBMIR/R-SBMIR method (which utilizes stochastic wavefront propagation) on the experimental data captured by a single-scan technique. Unlike a number of conventional phase retrieval algorithms, which may require a series of numerical experiments for determining optimal intensity distributions from a large dataset, disordered propagation of the estimation wavefront guarantees the high-contrast and high-resolution image reconstruction without pre-setting the parameters. It is shown that the package use of the single-scan technique with the subsequent data processing using the R-SBMIR algorithm has ap-plication potential for automation of the multi-plane phase retrieval in the THz range.

关键词： phase retrieval terahertz radiation iterative algorithm stochastic optimization cascade laser

来源：评论

学校读者我要写书评

暂无评论

A stopping criterion for iterative proton CT image reconstruction based on correlated noise properties

引用

JOURNAL OF APPLIED CLINICAL MEDICAL PHYSICS 2023年第9期24卷 e14114页

作者： DeJongh, Ethan A. A. Pryanichnikov, Alexander A. A. DeJongh, Don F. F. Schulte, Reinhard W. W. ProtonVDA LLC Naperville IL 60563 USA Moscow MV Lomonosov State Univ Moscow Russia Lebedev Phys Inst Phys Tech Ctr Protvino Russia Loma Linda Univ Loma Linda CA USA German Canc Res Ctr Div Biomed Phys Radiat Oncol Neuenheimer Feld 280 Heidelberg Germany

BackgroundWhereas filtered back projection algorithms for voxel-based CT image reconstruction have noise properties defined by the filter, iterative algorithms must stop at some point in their convergence and do not necessarily produce consistent noise properties for images with different degrees of heterogeneity. PurposeA least-squares iterative algorithm for proton CT (pCT) image reconstruction converges toward a unique solution for relative stopping power (RSP) that optimally fits the protons. We present a stopping criterion that delivers solutions with the property that correlations of RSP noise between voxels are relatively low. This provides a method to produce pCT images with consistent noise properties useful for proton therapy treatment planning, which relies on summing RSP along lines of voxels. Consistent noise properties will also be useful for future studies of image quality using metrics such as contrast to noise ratio, and to compare RSP noise and dose of pCT with other modalities such as dual-energy CT. MethodsWith simulated and real images with varying heterogeneity from a prototype clinical proton imaging system, we calculate average RSP correlations between voxel pairs in uniform regions-of-interest versus distance between voxels. We define a parameter r, the remaining distance to the unique solution relative to estimated RSP noise, and our stopping criterion is based on r falling below a chosen value. ResultsWe find large correlations between voxels for larger values of r, and anticorrelations for smaller values. For r in the range of 0.5-1, voxels are relatively uncorrelated, and compared to smaller values of r have lower noise with only slight loss of spatial resolution. Conclusionsiterative algorithms not using a specific metric or rationale for stopping iterations may produce images with an unknown and arbitrary level of convergence or smoothing. We resolve this issue by stopping iterations of a least-squares iterative algorithm when r reache

关键词： image noise iterative algorithm proton CT stopping criterion

来源：评论

学校读者我要写书评

暂无评论

iterative algorithm for solutions to new system of generalized mixed implicit equilibrium

引用

Applied Mathematics and Mechanics(English Edition) 2013年第1期34卷 113-126页

作者：丁协平 College of Mathematics and Software Science Sichuan Normal University

A new system of generalized mixed implicit equilibrium problems （SGMIEP） involving nonmonotone set-valued mappings is introduced and studied in real reflexive Banach spaces. First, an auxiliary mixed equilibrium problem （AMEP） is introduced. The existence and the uniqueness of the solutions to the AMEP are proved under quite mild assumptions without any coercive conditions. Next, by using the solution mapping of the AMEP, a system of generalized equation problems （SGEP） is considered, and its equivalence with the SGMIEP is shown. By using the SGEP, a new iterative algorithm for solving the SGMIEP is proposed and analyzed. The strong convergence of the iterative sequences generated by the algorithm is proved under suitable conditions. These results are new, which unify and generalize some recent results in this field.

关键词： system of generalized mixed implicit equilibrium problems （SGMIEP）,auxiliary mixed equilibrium problem （AMEP） system of generalized equation problems（SGEP） iterative algorithm reflexive Banach space

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：