Search results for "Artifact"
showing 10 items of 193 documents
Exploring the Affordances of SimReal for Learning Mathematics in Teacher Education: A Socio-Cultural Perspective
2020
SimReal is an innovative technology that emerged the last few years in mathematics education. It provides new potentialities for mathematical learning by means of dynamic and interactive visualizations of mathematical concepts. This paper uses SimReal in the context of teacher education to explore the affordances and constraints of the tool for the learning of mathematics. It presents a framework that combines Vygotsky’s socio-cultural theory, the role of mediation, and the notion of affordance at a technological, pedagogical, and socio-cultural level. The aim of the article is to explore the extent to which SimReal as a mediating artifact affords students’ mathematical learning in teacher …
Dynamic Perception of Plastic Movements: Biomechanics and Digital Artifacts
2017
The article offers some reflections on the body-space relationship through images, graphic translations and visual studies that converge into a contemporary digital illuminated avant-garde of the fourth virtual dimension. Starting from the study of the Soviet coreutics of the 1920s and the biomechanics of multimedia performances, it moves on the cinesthetic suggestions and to the dance theorization integrated with the musical score. Finally, some contemporary forms of digital image production are taken into account by addressing a number of issues regarding the exploration of the object-image and its experiential re-elaboration through the production of new graphic knowledge.
Length of endodontic files measured in digital radiographs with and without noise-suppression filters: an ex-vivo study
2011
The aim of this study is to evaluate if theoretically possible edge shifts induced by noise-suppression filters potentially occur on objects found in digital radiographs. Most manufacturers carry out noise-suppression filtering of their images before they are displayed to the user. It is not usually possible for the user to disrupt the function of the filters. The use of these filters can lead to deletion of small image structures.K-files (ISO size 06, 08, 10 and 15) were placed in the root canals of 6 human teeth located in cadaver jaw segments. File tip positions were measured on original and filtered digital images by three observers. The file position was marked on each filtered image a…
EMG artifacts removal during electrical stimulation, a CWT based technique
2014
International audience; A technique of artifacts removal based on the continuous wavelet transform is presented. It uses common mother wavelets to find the temporal localization of stimulation artifacts on electromyogram (EMG) signal during an electrically evoked contraction of a muscle. This method can be used with standard stimulation pulse waveforms like monophasics or biphasics ones. It uses a histogram representation to find the best threshold to apply on the CWT domain. The algotithm is presented with Haar wavelet and then it is used with common wavelet famillies such as Daubechies or Symlets.
Online Detection and Removal of Eye Blink Artifacts from Electroencephalogram
2020
The most prominent type of artifact contaminating electroencephalogram (EEG)signals are the eyeblink (EB) artifacts, which could potentially lead tomisinterpretation of the EEG signal. Online detection and removal of eyeblink artifacts from EEG signals are essential in applications such a Brain-Computer Interfaces (BCI), neurofeedback and epilepsy diagnosis. In this thesis, algorithms that combine unsupervised eyeblink artifact detection (eADA) with enhanced Empirical Mode Decomposition (FastEMD) and Canonical Correlation Analysis (CCA) are proposed,i.e. FastEMD-CCA2 and FastCCA, to automatically identify eyeblink artifacts andremove them in an online setting. FastEMD-CCA2 and FastCCA have …
Intracranial measurement of current densities induced by transcranial magnetic stimulation in the human brain
2003
Transcranial magnetic stimulation (TMS) is a non-invasive technique that uses the principle of electromagnetic induction to generate currents in the brain via pulsed magnetic fields. The magnitude of such induced currents is unknown. In this study we measured the TMS induced current densities in a patient with implanted depth electrodes for epilepsy monitoring. A maximum current density of 12 microA/cm2 was recorded at a depth of 1 cm from scalp surface with the optimum stimulation orientation used in the experiment and an intensity of 7% of the maximal stimulator output. During TMS we recorded relative current variations under different stimulating coil orientations and at different points…
Compensation of missing wedge effects with sequential statistical reconstruction in electron tomography.
2014
Electron tomography (ET) of biological samples is used to study the organization and the structure of the whole cell and subcellular complexes in great detail. However, projections cannot be acquired over full tilt angle range with biological samples in electron microscopy. ET image reconstruction can be considered an ill-posed problem because of this missing information. This results in artifacts, seen as the loss of three-dimensional (3D) resolution in the reconstructed images. The goal of this study was to achieve isotropic resolution with a statistical reconstruction method, sequential maximum a posteriori expectation maximization (sMAP-EM), using no prior morphological knowledge about …
Regional policies for sustainability in the Mediterranean countries: the role of a proper HVAC system maintenance in museums
2013
Italy, like several Mediterranean countries, holds a very large number of cultural artifacts that are often exhibited and saved inside museums. Museums are usually part of historical buildings that, not rarely, originally had a different intended use and that have been currently transformed in place for conservation and for exhibition of works of art. The use of historical buildings as museums leads to limitations in the management and distribution of exhibition space, in design and managing HVAC systems and in the achievement of targets relating to the continuous monitoring of the microclimate for people comfort and for preservation of works of art. Moreover, the costs of the operation and…
Mobile Robot and Mobile Manipulator Research Towards ASTM Standards Development
2016
International audience; Performance standards for industrial mobile robots and mobile manipulators (robot arms onboard mobile robots) have only recently begun development. Low cost and standardized measurement techniques are needed to characterize system performance, compare different systems, and to determine if recalibration is required. This paper discusses work at the National Institute of Standards and Technology (NIST) and within the ASTM Committee F45 on Driverless Automatic Guided Industrial Vehicles. This includes standards for both terminology, F45.91, and for navigation performance test methods, F45.02. The paper defines terms that are being considered. Additionally, the paper de…
Effect of Motion Artifact on Digital Camera Based Heart Rate Measurement
2017
International audience; Depression is one of the most prevalent mental disorders, burdening many people world-wide. A system with the potential of serving as a decision support system is proposed, based on novel features extracted from facial expression geometry and speech, by interpreting non-verbal manifestations of depression. The proposed system has been tested both in gender independent and gender based modes, and with different fusion methods. The algorithms were evaluated for several combinations of parameters and classification schemes, on the dataset provided by the Audio/Visual Emotion Challenge of 2013 and 2014. The proposed framework achieved a precision of 94.8% for detecting p…