Results 101 to 110 of about 993,426 (339)

The Requirement of a Positive Definite Covariance Matrix of Security Returns for Mean-Variance Portfolio Analysis: A Pedagogic Illustration

Spreadsheets in Education, 2010
This study considers, from a pedagogic perspective, a crucial requirement for the covariance matrix of security returns in mean-variance portfolio analysis.
Clarence C. Y. Kwan
doaj  

Analysis of brain structural covariance network in Cushing disease

Heliyon
Background: Cushing disease (CD) is a rare clinical neuroendocrine disease. CD is characterized by abnormal hypercortisolism induced by a pituitary adenoma with the secretion of adrenocorticotropic hormone.
Can-Xin Xu, Linghan Kong, Hong Jiang, Yue Jiang, Yu-Hao Sun, Liu-Guan Bian, Yuan Feng, Qing-Fang Sun   +7 more
doaj   +1 more source

Voxel-wise Intermodal Coupling Analysis of Two or More Modalities using Local Covariance Decomposition [PDF]

, 2022
Fengling Hu, Sarah M. Weinstein, Erica B. Baller, Alessandra M. Valcarcel, Azeez Adebimpe, Armin Raznahan, David R. Roalf, Timothy Robert‐Fitzgerald, Virgilio Gonzenbach, Ruben C. Gur, Raquel E. Gur, Simon Vandekar, John A. Detre, Kristin A. Linn, Aaron Alexander‐Bloch, Theodore D. Satterthwaite, Russell T. Shinohara   +16 more
openalex   +1 more source

UniMR: A Plug‐and‐Play Framework of Automated Molecular Recognition for Scanning Tunneling Microscopy

Advanced Science, EarlyView.
UniMR, a training‐free framework for automated molecular recognition in STM images. By integrating adaptive feature selection with CLIP embeddings and Gaussian Mixture Modeling, UniMR achieves robust performance across diverse molecular systems and low‐resolution conditions.
Ziqiang Cao, Lingyin Zhang, Bingzheng Wu, Haonan Chen, Junhao Sun, Linghao Yan, Wenfei Li, Yangyang Wu, Zhifang Wang, Qigang Zhong, Lifeng Chi   +10 more
wiley   +1 more source

Novel Process Noise Model for GNSS Kalman Filter Based on Sensitivity Analysis of Covariance with Poor Satellite Geometry. [PDF]

Sensors (Basel), 2021
Takayama Y, Urakubo T, Tamaki H.
europepmc   +1 more source

Long and short arc altitude determination for GEOS-C [PDF]

The accuracy with which the GEOS-C altitude may be estimated over long (7 day) and short (40 minute) orbital arcs is investigated. Over the long are excellent agreement was attained between a simulation of the orbit determination process and a covariance
Argentiero, P., Kahn, W. D., Koch, D.
core   +1 more source

TOPK Inhibition Promotes Anti‐Tumor Immunity Via eIF4F Complex Mediated STAT1 Translation in Gastric Cancer

Advanced Science, EarlyView.
This study identifies TOPK as a dual‐function target in gastric cancer: it drives tumor cell proliferation and migration, and under IFN‐γ stimulation, phosphorylates eIF4F complex component eIF4A1 to enhance STAT1 mRNA translation, thereby promoting PD‐L1/IDO1‐mediated tumor immunometabolic evasion.
Junbing Chen, Longtao Huangfu, Gangjian Wang, Xueying Wang, Huanbo Zhu, Qian Yao, Cong Chen, Xiaohuan Tang, Ting Guo, Biao Fan, Xingyang Liu, Qingda Li, Zining Liu, Ying Hu, Tianze Sun, Jiafu Ji, Xiaofang Xing   +16 more
wiley   +1 more source

Towards Analysis of Covariance Descriptors via Bures–Wasserstein Distance

Mathematics
A brain–computer interface (BCI) provides a direct communication pathway between the human brain and external devices, enabling users to control them through thought.
Huajun Huang, Yuexin Li, Shu-Chin Lin, Yuyan Yi, Jingyi Zheng   +4 more
doaj   +1 more source

The affine equivariant sign covariance matrix: asymptotic behavior and efficiencies. [PDF]

We consider the affine equivariant sign covariance matrix (SCM) introduced by Visuri et al. (J. Statist. Plann. Inference 91 (2000) 557). The population SCM is shown to be proportional to the inverse of the regular covariance matrix. The eigenvectors and
Croux, Christophe, Oja, H, Ollila, E
core  

Solid Harmonic Wavelet Bispectrum for Image Analysis

Advanced Science, EarlyView.
The Solid Harmonic Wavelet Bispectrum (SHWB), a rotation‐ and translation‐invariant descriptor that captures higher‐order (phase) correlations in signals, is introduced. Combining wavelet scattering, bispectral analysis, and group theory, SHWB achieves interpretable, data‐efficient representations and demonstrates competitive performance across texture,
Alex Brown, Mathilda Avirett‐Mackenzie, Carolin Villforth, Georgios Exarchakis   +3 more
wiley   +1 more source