Search results for "Pattern"
showing 10 items of 4203 documents
A Multi-Projector Calibration Method for Virtual Reality Simulators with Analytically Defined Screens
2017
The geometric calibration of projectors is a demanding task, particularly for the industry of virtual reality simulators. Different methods have been developed during the last decades to retrieve the intrinsic and extrinsic parameters of projectors, most of them being based on planar homographies and some requiring an extended calibration process. The aim of our research work is to design a fast and user-friendly method to provide multi-projector calibration on analytically defined screens, where a sample is shown for a virtual reality Formula 1 simulator that has a cylindrical screen. The proposed method results from the combination of surveying, photogrammetry and image processing approac…
Space-by-Time Modular Decomposition Effectively Describes Whole-Body Muscle Activity During Upright Reaching in Various Directions
2017
The modular control hypothesis suggests that motor commands are built from precoded modules whose specific combined recruitment can allow the performance of virtually any motor task. Despite considerable experimental support, this hypothesis remains tentative as classical findings of reduced dimensionality in muscle activity may also result from other constraints (biomechanical couplings, data averaging or low dimensionality of motor tasks). Here we assessed the effectiveness of modularity in describing muscle activity in a comprehensive experiment comprising 72 distinct point-to-point whole-body movements during which the activity of 30 muscles was recorded. To identify invariant modules o…
Vegetation series as a marker of interactions between rural settlements and landscape: new insights from the archaeological record in Western Sicily
2020
[EN] Plant communities are complex and dynamic elements of the landscape, intertwined with both natural factors and human activities. Vegetation series reflect the environmental characteristics of the landscape, but also the anthropic impact, one of the exogenous forces that most profoundly affects the landscape formation process. This paper aims to investigate the interactions between long-term human settlement catchment areas and vegetation series. The case study area of the Sicani Mountains (Central-Western Sicily) proved to be an ideal place to perform GIS-based spatial analysis in order to compare a data set of rural archaeological sites and land units created through the mapping of ve…
Miega higiēna pusaudžiem Latvijā
2018
Mērķis: Šī pētījuma mērķis ir izvērtēt miega higiēnas paradumus Latvijas pusaudžu vidū un analizēt faktorus, kas ietekmē jauniešu miega higiēnu. Izmantotās metodes: Piecās Latvijas skolās tika veikts iedzīvotāju šķērsgriezuma pētījums. Pusaudžiem tika lūgts aizpildīt anketu par miega higiēnas indeksu (SHI), un tā parametri tika novērtēti attiecībā uz svara procentīli, vecumu, dzimumu un miega kvalitātes pašnovērtējumu. Statistikā analīze tika veikta, izmantojot SPSS programmatūru ar būtiskuma slieksni p < 0.05. Lai pārbaudītu hipotēzes, tika veikts neatkarīgs izlases veida t-tests, dispersijas analīze ar Post-hoc testu, hī kvadrāta tests, Šapīro-Vilka tests un tika izmantots Pīrsona korelāc…
Creating Office Spaces in the Mediterranean. The importance of well-being, health and performance of office users
2018
Recent research has studied the influence of office buildings indoor environment quality (IEQ) on employees’ well-being, health and performance. However, it seems that it has not been explicitly explored what are the appropriate environmental conditions to different work patterns that coexist in these spaces. This paper presents results of an empirical research, based on the synchronized measurements of different IEQ parameters (i.e., noise, lighting and temperature), and well-being, health and performance of 71 employees in twelve office spaces in the Valencian Community along three periods, considering winter and summer conditions. Findings of the first winter period data, suggest the exi…
Multispectral filter arrays: Recent advances and practical implementation
2014
Thanks to some technical progress in interferencefilter design based on different technologies, we can finally successfully implement the concept of multispectral filter array-based sensors. This article provides the relevant state-of-the-art for multispectral imaging systems and presents the characteristics of the elements of our multispectral sensor as a case study. The spectral characteristics are based on two different spatial arrangements that distribute eight different bandpass filters in the visible and near-infrared area of the spectrum. We demonstrate that the system is viable and evaluate its performance through sensor spectral simulation. Multispectral filter arrays: Recent advan…
Measuring the Task Induced Oscillatory Brain Activity Using Tensor Decomposition
2019
The characterization of dynamic electrophysiological brain activity, which form and dissolve in order to support ongoing cognitive function, is one of the most important goals in neuroscience. Here, we introduce a method with tensor decomposition for measuring the task-induced oscillations in the human brain using electroencephalography (EEG). The time frequency representation of source-reconstructed singletrail EEG data constructed a third-order tensor with three factors of time ∗ trails, frequency and source points. We then used a non-negative Canonical Polyadic decomposition (NCPD) to identify the temporal, spectral and spatial changes in electrophysiological brain activity. We validate …
Optical Monitoring of Microplastics Filtrated from Wastewater Sludge and Suspended in Ethanol.
2021
The abundance of microplastics (MPs) in the atmosphere, on land, and especially in water bodies is well acknowledged. In this study, we establish an optical method based on three different techniques, namely, specular reflection to probe the medium, transmission spectroscopy measurements for the detection and identification, and a speckle pattern for monitoring the sedimentation of MPs filtrated from wastewater sludge and suspended in ethanol. We used first Raman measurements to estimate the presence and types of different MPs in wastewater sludge samples. We also used microscopy to identify the shapes of the main MPs. This allowed us to create a teaching set of samples to be characterized …
Stability of stochastic nonlinear systems with state-dependent switching
2013
In this paper, the problem of stability on stochastic systems with state-dependent switching is investigated. To analyze properties of the switched system by means of Itô’s formula and Dynkin’s formula, it is critical to show switching instants being stopping times. When the given active-region set can be replaced by its interior, the local solution of the switched system is constructed by defining a series of stopping times as switching instants, and the criteria on global existence and stability of solution are presented by Lyapunov approach. For the case where the active-region set can not be replaced by its interior, the switched systems do not necessarily have solutions, thereby quasi-…
Primitives extraction based on structured-light images
2013
International audience; Geometric attributes such as curvature or surface orientation are additional information of the 3D points obtained after the scanning of an object. In the classic 3D chain, characterized by a sequential structure, these information are determined from the dense point cloud (from a 3D scanner). Then, they are used to reduce the amount of information and allows to obtain a simplified model. In this paper, we investigate the possibility to extract some geometric attributes, directly from 2D images obtained by the camera of a structured-light system.