In this paper,we first obtain the precise values of the univalent radius and the Bloch constant for harmonic mappings of the formL(f)=zfz-zfz,where f represents normalized harmonic mappings with bounded dilation.Then,...In this paper,we first obtain the precise values of the univalent radius and the Bloch constant for harmonic mappings of the formL(f)=zfz-zfz,where f represents normalized harmonic mappings with bounded dilation.Then,using these results,we present better estimations for the Bloch constants of certain harmonic mappings L(f),where f is a K-quasiregular harmonic or open harmonic.Finally,we establish three versions of BlochLandau type theorem for biharmonic mappings of the form L(f).These results are sharp in some given cases and improve the related results of earlier authors.展开更多
The main purpose of this paper is to investigate the univalence of normalized polyharmonic mappings with bounded length distortions in the unit disk.We first establish the coefficient estimates for polyharmonic mappin...The main purpose of this paper is to investigate the univalence of normalized polyharmonic mappings with bounded length distortions in the unit disk.We first establish the coefficient estimates for polyharmonic mappings with bounded length distortions.Then,using these results,we establish five Landau-type theorems for subclasses of polyharmonic mappings F and L(F),where F has bounded length distortion and L is a differential operator.展开更多
The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevita-bly affected by the orbiter attitude jitter.Therefore,it is necessary to conduct preliminary research on the stereo m...The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevita-bly affected by the orbiter attitude jitter.Therefore,it is necessary to conduct preliminary research on the stereo mapping camera equipped on lunar orbiter before launching.In this work,an imaging simulation method consid-ering the attitude jitter is presented.The impact analysis of different attitude jitter on terrain undulation is conduct-ed by simulating jitter at three attitude angles,respectively.The proposed simulation method is based on the rigor-ous sensor model,using the lunar digital elevation model(DEM)and orthoimage as reference data.The orbit and attitude of the lunar stereo mapping camera are simulated while considering the attitude jitter.Two-dimensional simulated stereo images are generated according to the position and attitude of the orbiter in a given orbit.Experi-mental analyses were conducted by the DEM with the simulated stereo image.The simulation imaging results demonstrate that the proposed method can ensure imaging efficiency without losing the accuracy of topographic mapping.The effect of attitude jitter on the stereo mapping accuracy of the simulated images was analyzed through a DEM comparison.展开更多
This paper presents a systematic methodology for analyzing and optimizing an innovative antenna mount designed for phased array antennas, implemented through a novel 2-PSS&1-RR circular-rail parallel mechanism. In...This paper presents a systematic methodology for analyzing and optimizing an innovative antenna mount designed for phased array antennas, implemented through a novel 2-PSS&1-RR circular-rail parallel mechanism. Initially, a comparative motion analysis between the 3D model of the mount and its full-scale prototype is conducted to validate effectiveness. Given the inherent complexity, a kinematic mapping model is established between the mount and the crank-slider linkage, providing a guiding framework for subsequent analysis and optimization. Guided by this model, feasible inverse and forward solutions are derived, enabling precise identification of stiffness singularities. The concept of singularity distance is thus introduced to reflect the structural stiffness of the mount. Subsequently, also guided by the mapping model, a heuristic algorithm incorporating two backtracking procedures is developed to reduce the mount's mass. Additionally, a parametric finite-element model is employed to explore the relation between singularity distance and structural stiffness. The results indicate a significant reduction(about 16%) in the antenna mount's mass through the developed algorithm, while highlighting the singularity distance as an effective stiffness indicator for this type of antenna mount.展开更多
This work aims to develop fast T_(1)mapping methods for preclinical and clinical scanners based on subspace-constrained reconstructions.Two sequences are explored for rapid T_(1)characterizations:1)Interleaved spatiot...This work aims to develop fast T_(1)mapping methods for preclinical and clinical scanners based on subspace-constrained reconstructions.Two sequences are explored for rapid T_(1)characterizations:1)Interleaved spatiotemporal encoding incorporating variable repetition times.2)Inversion recovery gradient echo with random sampling of the phaseencoding(PE)dimension.For both sequences,the subspace reconstruction of the signal recovery was applied,to jointly reconstruct the down-sampled images while characterizing the T_(1)relaxation.In vivo scans on human brains and abdomens confirmed the efficiency of the proposed methods,including compatibility with breath-holding.In addition,Scans on animals with abdominal tumors and dynamic contrast-enhanced T_(1)mapping on kidneys support the applicability of the proposed methods also in preclinical settings.展开更多
As the number of single-cell datasets continues to grow rapidly,workflows that map new data to well-curated reference atlases offer enormous promise for the biological community.In this perspective,we discuss key comp...As the number of single-cell datasets continues to grow rapidly,workflows that map new data to well-curated reference atlases offer enormous promise for the biological community.In this perspective,we discuss key computational challenges and opportunities for single-cell reference-mapping algorithms.We discuss how mapping algorithms will enable the integration of diverse datasets across disease states,molecular modalities,genetic perturbations,and diverse species and will eventually replace manual and laborious unsupervised clustering pipelines.展开更多
多模态苹果派(multimodal APPLE PIE, MAP)基于多模态教学原则以及交互性教学原则,在教学过程中以有效性、互动性和参与性为核心,对解决当前考研英语教学中存在的问题具有重要指导意义。因此,探究考研英语教学现状,提出MAP原则指导下实...多模态苹果派(multimodal APPLE PIE, MAP)基于多模态教学原则以及交互性教学原则,在教学过程中以有效性、互动性和参与性为核心,对解决当前考研英语教学中存在的问题具有重要指导意义。因此,探究考研英语教学现状,提出MAP原则指导下实现考研英语线上虚拟课堂的教学设计,从课堂导入、课程呈现、学生合作学习、人机互动、课堂互动5个环节探究考研英语线上虚拟课堂的教学过程,以期提高教师的教学质量以及增强学生的学习效果。展开更多
Differential spatial modulation(DSM)is a multiple-input multiple-output(MIMO)transmission scheme.It has attracted extensive research interest due to its ability to transmit additional data without increasing any radio...Differential spatial modulation(DSM)is a multiple-input multiple-output(MIMO)transmission scheme.It has attracted extensive research interest due to its ability to transmit additional data without increasing any radio frequency chain.In this paper,DSM is investigated using two mapping algorithms:Look-Up Table Order(LUTO)and Permutation Method(PM).Then,the bit error rate(BER)performance and complexity of the two mapping algorithms in various antennas and modulation methods are verified by simulation experiments.The results show that PM has a lower BER than the LUTO mapping algorithm,and the latter has lower complexity than the former.展开更多
Existing chaotic encryption schemes primarily focus on single types of images,making the design of hybrid image encryption schemes more suitable for practical applications.In this paper,a hyperchaotic map with a spher...Existing chaotic encryption schemes primarily focus on single types of images,making the design of hybrid image encryption schemes more suitable for practical applications.In this paper,a hyperchaotic map with a spherical attractor is proposed,which is constructed using spherical coordinates.Dynamical analyses reveal that the hyperchaotic map exhibits global hyperchaos and high complexity,making it capable of generating more complex chaotic sequences suitable for image encryption.A hybrid encryption scheme based on a hyperchaotic map is proposed for two-dimensional(2D)images,three-dimensional(3D)models,and 3D point clouds.Firstly,the pixels of 2D image and the coordinate data of 3D image are fused into a plaintext cube,which is combined with Hash-512 to obtain the initial value of the hyperchaotic map.Chaotic sequences are utilized for cube space internal confusion and dynamic cross-diffusion.The encrypted images demonstrate high information entropy,and the test results show that the encryption scheme effectively protects the images.The proposed hybrid image encryption scheme provides an efficient solution for securing various types of images.展开更多
基金supported by the Natural Science Foundation of Guangdong Province(2021A1515010058)。
文摘In this paper,we first obtain the precise values of the univalent radius and the Bloch constant for harmonic mappings of the formL(f)=zfz-zfz,where f represents normalized harmonic mappings with bounded dilation.Then,using these results,we present better estimations for the Bloch constants of certain harmonic mappings L(f),where f is a K-quasiregular harmonic or open harmonic.Finally,we establish three versions of BlochLandau type theorem for biharmonic mappings of the form L(f).These results are sharp in some given cases and improve the related results of earlier authors.
基金supported by the Natural Science Foundation of Guangdong Province(2021A1515010058)supported by the Youth Innovation Foundation of Shenzhen Polytechnic University(6024310023K)。
文摘The main purpose of this paper is to investigate the univalence of normalized polyharmonic mappings with bounded length distortions in the unit disk.We first establish the coefficient estimates for polyharmonic mappings with bounded length distortions.Then,using these results,we establish five Landau-type theorems for subclasses of polyharmonic mappings F and L(F),where F has bounded length distortion and L is a differential operator.
基金Supported by the National Natural Science Foundation of China(42221002,42171432)Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)the Fundamental Research Funds for the Central Universities.
文摘The geometric accuracy of topographic mapping with high-resolution remote sensing images is inevita-bly affected by the orbiter attitude jitter.Therefore,it is necessary to conduct preliminary research on the stereo mapping camera equipped on lunar orbiter before launching.In this work,an imaging simulation method consid-ering the attitude jitter is presented.The impact analysis of different attitude jitter on terrain undulation is conduct-ed by simulating jitter at three attitude angles,respectively.The proposed simulation method is based on the rigor-ous sensor model,using the lunar digital elevation model(DEM)and orthoimage as reference data.The orbit and attitude of the lunar stereo mapping camera are simulated while considering the attitude jitter.Two-dimensional simulated stereo images are generated according to the position and attitude of the orbiter in a given orbit.Experi-mental analyses were conducted by the DEM with the simulated stereo image.The simulation imaging results demonstrate that the proposed method can ensure imaging efficiency without losing the accuracy of topographic mapping.The effect of attitude jitter on the stereo mapping accuracy of the simulated images was analyzed through a DEM comparison.
基金financed by the National Key Research and Development Program of China,High efficiency space satellite charging system based on microwave wireless energy transfer technology(Grant No.2021YFB3900304)。
文摘This paper presents a systematic methodology for analyzing and optimizing an innovative antenna mount designed for phased array antennas, implemented through a novel 2-PSS&1-RR circular-rail parallel mechanism. Initially, a comparative motion analysis between the 3D model of the mount and its full-scale prototype is conducted to validate effectiveness. Given the inherent complexity, a kinematic mapping model is established between the mount and the crank-slider linkage, providing a guiding framework for subsequent analysis and optimization. Guided by this model, feasible inverse and forward solutions are derived, enabling precise identification of stiffness singularities. The concept of singularity distance is thus introduced to reflect the structural stiffness of the mount. Subsequently, also guided by the mapping model, a heuristic algorithm incorporating two backtracking procedures is developed to reduce the mount's mass. Additionally, a parametric finite-element model is employed to explore the relation between singularity distance and structural stiffness. The results indicate a significant reduction(about 16%) in the antenna mount's mass through the developed algorithm, while highlighting the singularity distance as an effective stiffness indicator for this type of antenna mount.
基金funded by the Israel Science Foundation(grants 3594/21 and 1874/22)the Clore Institute for High Field Magnetic Resonance Imaging and Spectroscopy and by the Azrieli Institute for Brain Imaging(Weizmann Institute),by China Scholarship Council(CSC)grant 201806310085+2 种基金the National Key Research and Development Program grant 2023YFE0113300the Magnetic Resonance Technology Alliance of the Chinese Academy of Sciences Scientific Research Instrument and Equipment Development Project grant 2021GZL001the Israel Cancer Research Foundation and by Israel's Planning and Budget Committee(Lingceng Ma,international student fellowship).
文摘This work aims to develop fast T_(1)mapping methods for preclinical and clinical scanners based on subspace-constrained reconstructions.Two sequences are explored for rapid T_(1)characterizations:1)Interleaved spatiotemporal encoding incorporating variable repetition times.2)Inversion recovery gradient echo with random sampling of the phaseencoding(PE)dimension.For both sequences,the subspace reconstruction of the signal recovery was applied,to jointly reconstruct the down-sampled images while characterizing the T_(1)relaxation.In vivo scans on human brains and abdomens confirmed the efficiency of the proposed methods,including compatibility with breath-holding.In addition,Scans on animals with abdominal tumors and dynamic contrast-enhanced T_(1)mapping on kidneys support the applicability of the proposed methods also in preclinical settings.
文摘As the number of single-cell datasets continues to grow rapidly,workflows that map new data to well-curated reference atlases offer enormous promise for the biological community.In this perspective,we discuss key computational challenges and opportunities for single-cell reference-mapping algorithms.We discuss how mapping algorithms will enable the integration of diverse datasets across disease states,molecular modalities,genetic perturbations,and diverse species and will eventually replace manual and laborious unsupervised clustering pipelines.
文摘多模态苹果派(multimodal APPLE PIE, MAP)基于多模态教学原则以及交互性教学原则,在教学过程中以有效性、互动性和参与性为核心,对解决当前考研英语教学中存在的问题具有重要指导意义。因此,探究考研英语教学现状,提出MAP原则指导下实现考研英语线上虚拟课堂的教学设计,从课堂导入、课程呈现、学生合作学习、人机互动、课堂互动5个环节探究考研英语线上虚拟课堂的教学过程,以期提高教师的教学质量以及增强学生的学习效果。
基金supported by the National Natural Science Foundation of China(NSFC)under Grant No.62061024the Project of Gansu Province Science and Technology Department under Grant No.22ZD6GA055.
文摘Differential spatial modulation(DSM)is a multiple-input multiple-output(MIMO)transmission scheme.It has attracted extensive research interest due to its ability to transmit additional data without increasing any radio frequency chain.In this paper,DSM is investigated using two mapping algorithms:Look-Up Table Order(LUTO)and Permutation Method(PM).Then,the bit error rate(BER)performance and complexity of the two mapping algorithms in various antennas and modulation methods are verified by simulation experiments.The results show that PM has a lower BER than the LUTO mapping algorithm,and the latter has lower complexity than the former.
基金Project supported by the Basic Scientific Research Projects of Department of Education of Liaoning Province,China(Grant No.LJ212410152049)the Technological Innovation Projects in the field of artificial intelligence of Liaoning Province,China(Grant No.2023JH26/10300011)。
文摘Existing chaotic encryption schemes primarily focus on single types of images,making the design of hybrid image encryption schemes more suitable for practical applications.In this paper,a hyperchaotic map with a spherical attractor is proposed,which is constructed using spherical coordinates.Dynamical analyses reveal that the hyperchaotic map exhibits global hyperchaos and high complexity,making it capable of generating more complex chaotic sequences suitable for image encryption.A hybrid encryption scheme based on a hyperchaotic map is proposed for two-dimensional(2D)images,three-dimensional(3D)models,and 3D point clouds.Firstly,the pixels of 2D image and the coordinate data of 3D image are fused into a plaintext cube,which is combined with Hash-512 to obtain the initial value of the hyperchaotic map.Chaotic sequences are utilized for cube space internal confusion and dynamic cross-diffusion.The encrypted images demonstrate high information entropy,and the test results show that the encryption scheme effectively protects the images.The proposed hybrid image encryption scheme provides an efficient solution for securing various types of images.
文摘目的 本研究应用MRI对关节镜下微骨折法治疗膝关节软骨损伤修复效果进行大体组织形态学评估及定量分析.方法 本研究纳入14例有膝关节软骨损伤症状并接受关节镜下微骨折法治疗的病例进行回顾性病例分析.所有病例的关节软骨损伤均为ICRS分级Ⅲ或Ⅳ,术中测量病变面积为2～8cm^2.1年随访期内所有病例都接受常规MRI序列及T2 star mapping序列扫描（1.5T）.对损伤修复区域采用软骨组织修复磁共振观察评分系统（MOCART）进行评价.采用T2 star mapping序列扫描图像感兴趣区划分的方法对修复区域及自身正常软骨所测量的T2＊弛豫值进行分析比较.结果 1年随访期软骨修复区MOCART评分为59.50±23.90,相邻本体软骨组织评分为65.21±21.84,与软骨修复组间比较无显著差异.软骨修复区和邻近正常自体软骨组织T2＊弛豫时间分别为（31.14±9.26）ms和（32.93±11.69）ms,修复区软骨组织质地与正常软骨组织相近.结论 经关节镜下微骨折法修复膝关节软骨损伤后1年随访观察期内,MRI软骨扫描可见软骨损伤区填充良好.经T2＊测量值分析证实软骨修复组织可以达到与邻近正常透明软骨相近的组织结构.
