Search results for "projection"
showing 10 items of 378 documents
Examining stability of independent component analysis based on coefficient and component matrices for voxel-based morphometry of structural magnetic …
2018
Independent component analysis (ICA) on group-level voxel-based morphometry (VBM) produces the coefficient matrix and the component matrix. The former contains variability among multiple subjects for further statistical analysis, and the latter reveals spatial maps common for all subjects. ICA algorithms converge to local optimization points in practice and the mostly applied stability investigation approach examines the stability of the extracted components. We found that the practically stable components do not guarantee to produce the practically stable coefficients of ICA decomposition for the further statistical analysis. Consequently, we proposed a novel approach including two steps: …
Single-trial-based temporal principal component analysis on extracting event-related potentials of interest for an individual subject.
2023
Background: Temporal principal component analysis (tPCA) has been widely used to extract event-related potentials (ERPs) at group level of multiple subjects ERP data and it assumes that the underlying factor loading is fixed across participants. However, such assumption may fail to work if latency and phase for one ERP vary considerably across participants. Furthermore, effect of number of trials on tPCA decomposition has not been systematically examined as well, especially for within-subject PCA. New method: We reanalyzed a real ERP data of an emotional experiment using tPCA to extract N2 and P2 from single-trial EEG of an individual. We also explored influence of the number of trials (con…
The central control of oriented locomotion in insects - towards a neurobiological model
2010
A neurobiological model for the higher control of oriented locomotion in insects is developed here. It is based on studies in a genetic model insect, the fruit fly Drosophila melangaster. Reference is made to other insects, where respective functions are not yet studied in Drosophila. Flies can walk swiftly with up to 16 steps per second, each leg, on almost any substrate and in any orientation to the gravity vector. To bring about this astounding maneuverability and agility the central complex within the insect brain derives directional commands for the leg coordination centers in the thoracic nervous system. Neuroanatomical information is taken into account with regard to the general flow…
Alternative method for binary shape alignment of non-symmetrical shapes based on minimal enclosing box
2012
Proposed is a novel method based on the minimal enclosing box (MEB) to determine the canonical orientation associated with a three-dimensional binary shape. It is suggested that, when the shape has no clear distinctive features and two or more of the eigenvalues are similar, this method is more suitable than the commonly used method based on principal component analysis (PCA). An experiment is performed with shapes of human livers by measuring the degree on which a prototypical image (atlas) matches to a new shape after alignment by PCA, minimal area projection (MAP), and MEB showing that in this case MEB outperforms the usual PCA-based alignment method and also the MAP method.
2D-3D Camera Fusion for Visual Odometry in Outdoor Environments
2014
International audience; Accurate estimation of camera motion is very important for many robotics applications involving SfM and visual SLAM. Such accuracy is attempted by refining the estimated motion through nonlinear optimization. As many modern robots are equipped with both 2D and 3D cameras, it is both highly desirable and challenging to exploit data acquired from both modalities to achieve a better localization. Existing refinement methods, such as Bundle adjustment and loop closing, may be employed only when precise 2D-to-3D correspondences across frames are available. In this paper, we propose a framework for robot localization that benefits from both 2D and 3D information without re…
Quality based classification of gasoline samples by ATR-FTIR spectrometry using spectral feature selection with quadratic discriminant analysis
2013
Abstract A chemometric approach has been developed for characterization of gasoline samples regarding their quality. Attenuated total reflectance – infrared spectrometric data were processed by genetic algorithm (GA) and successive projection algorithm (SPA) feature selection techniques, being employed as an initial step prior to apply a discriminative tool. It was aimed to classify the fuel samples according to their quality passed/failed data. Chemometric predictive procedures were developed using quadratic discriminant analysis (QDA) combined with GA and SPA as a feature subset and feature selection strategy. Results showed 93.3% and 95.6% accuracy for SPA-QDA and GA-QDA models respectiv…
The Geometry of a Domed Architecture: A Stately Example of Kārbandi at Bagh-e Dolat Abad in Yazd
2016
This paper analyses the kārbandi of the Hashti pavilion at Bagh-e-Dolat Abad in Yazd. Kārbandi is a spatial system obtained through the projection of a star-shaped drawing onto a curved surface. It is characterised by a complex use of geometry and repetitive symmetry. The analysis of its geometrical aspects contributes to an understanding of the traditional rules underlying the original design. The kārbandi of the octagonal vestibule of the Hashti pavilion consists of a complex roof system that completes the octagonal volume of the room below; its intrados presents a pattern of interlocking ribbed arches. The paper also looks at the drawings, module and proportions of the Hashti pavilion, w…
Analyse spectrale et texturale de données à haute résolution pour la détection automatique des maladies de la vigne
2019
‘Flavescence dorée’ is a contagious and incurable disease present on the vine leaves. In order to contain the infection, the regulations require growers to control each of the vine rows and to remove the suspect vine plants. This monitoring is done on foot during the harvest and mobilizes many people during a strategic period for viticulture. In order to solve this problem, the DAMAV project (Automatic detection of Vine Diseases) aims to develop a solution for automated detection of vine diseases using a micro-drone. The goal is to offer a turnkey solution for wine growers. This tool will allow the search for potential foci, and then more generally any type of vine diseases detectable on th…
Demographic inequalities as determinants and consequences of the COVID-19 pandemic in Latvia
2021
Since early March 2020 Latvia is fighting the COVID-19 pandemic. Lessons learned from this crisis will be instrumental in shaping future public health policy. Any policy response to the pandemic must be tailored to the particular risks within population in order to avoid the unnecessary social and economic damage on a national and international scale. Available literature on the topic highlights region-specific demographic factors associated with elevated population vulnerability to the effects of the COVID-19 pandemic. This study aims to ascertain the role of a pre-existing demographic inequalities in Latvia in the onset and progression of COVID-19 pandemic and lay groundwork for projectin…
Search for heavy neutrinos with the T2K near detector ND280
2019
This paper reports on the search for heavy neutrinos with masses in the range 140<MN<493 MeV/c2 using the off-axis near detector ND280 of the T2K experiment. These particles can be produced from kaon decays in the standard neutrino beam and then subsequently decay in ND280. The decay modes under consideration are N→ℓ±απ∓ and N→ℓ+αℓ−β(−)ν(α,β=e,μ). A search for such events has been made using the Time Projection Chambers of ND280, where the background has been reduced to less than two events in the current dataset in all channels. No excess has been observed in the signal region. A combined Bayesian statistical approach has been applied to extract upper limits on the mixing elements of heav…