41 research outputs found
AVEID: Automatic Video System for Measuring Engagement In Dementia
Engagement in dementia is typically measured using behavior observational
scales (BOS) that are tedious and involve intensive manual labor to annotate,
and are therefore not easily scalable. We propose AVEID, a low cost and
easy-to-use video-based engagement measurement tool to determine the engagement
level of a person with dementia (PwD) during digital interaction. We show that
the objective behavioral measures computed via AVEID correlate well with
subjective expert impressions for the popular MPES and OME BOS, confirming its
viability and effectiveness. Moreover, AVEID measures can be obtained for a
variety of engagement designs, thereby facilitating large-scale studies with
PwD populations
A hot X-ray filament associated with A3017 galaxy cluster
Recent simulations and observations have shown large scale filaments in the
cosmic web connecting nodes, with accreting materials (baryonic and dark
matter) flowing through them. Current high sensitivity observations also show
that the propagation of shocks through filaments can heat them up, and make
filaments visible between two or more galaxy clusters or around massive
clusters, based on optical and/or X-ray observations. We are reporting here the
special case of the cluster A3017 associated with a hot filament. The
temperature of the filament is 3.4 ~keV and its length is
1 Mpc. We have analysed its archival {\it Chandra} data and report
various properties. We also analysed GMRT 235/610 MHz radio data. Radio
observations have revealed symmetric two-sided lobes which fill cavities in the
A3017 cluster core region, associated with central AGN. In the radio map, we
also noticed a peculiar linear vertical radio structure in the X-ray filament
region which might be associated with a cosmic filament shock. This radio
structure could be a radio phoenix or old plasma where an old relativistic
population is re-accelerated by shock propagation. Finally we put an upper
limit on the radio luminosity of the filament region
Investigating the generalizability of EEG-based Cognitive Load Estimation Across Visualizations
We examine if EEG-based cognitive load (CL) estimation is generalizable
across the character, spatial pattern, bar graph and pie chart-based
visualizations for the nback~task. CL is estimated via two recent approaches:
(a) Deep convolutional neural network, and (b) Proximal support vector
machines. Experiments reveal that CL estimation suffers across visualizations
motivating the need for effective machine learning techniques to benchmark
visual interface usability for a given analytic task
An EEG-Based Image Annotation System
The success of deep learning in computer vision has greatly increased the need for annotated image datasets. We propose an EEG (Electroencephalogram)-based image annotation system. While humans can recognize objects in 20–200 ms, the need to manually label images results in a low annotation throughput. Our system employs brain signals captured via a consumer EEG device to achieve an annotation rate of up to 10 images per second. We exploit the P300 event-related potential (ERP) signature to identify target images during a rapid serial visual presentation (RSVP) task. We further perform unsupervised outlier removal to achieve an F1-score of 0.88 on the test set. The proposed system does not depend on category-specific EEG signatures enabling the annotation of any new image category without any model pre-training
Mining mini-halos with MeerKAT I. Calibration and imaging
Radio mini-halos are clouds of diffuse, low-surface brightness synchrotron emission that surround the Brightest Cluster Galaxy
(BCG) in massive cool-core galaxy clusters. In this paper, we use third generation calibration (3GC), also called directiondependent (DD) calibration, and point source subtraction on MeerKAT extragalactic continuum data. We calibrate and image
archival MeerKAT L-band observations of a sample of five galaxy clusters (ACO 1413, ACO 1795, ACO 3444, MACS
J1115.8+0129, MACS J2140.2-2339). We use the CARACal pipeline for direction-independent (DI) calibration, DDFacet and
killMS for 3GC, followed by visibility-plane point source subtraction to image the underlying mini-halo without bias from any
embedded sources. Our 3GC process shows a drastic improvement in artefact removal, to the extent that the local noise around
severely affected sources was halved and ultimately resulted in a 7 per cent improvement in global image noise. Thereafter,
using these spectrally deconvolved Stokes I continuum images, we directly measure for four mini-halos the flux density, radio
power, size, and in-band integrated spectra. Further to that, we show the in-band spectral index maps of the mini-halo (with point
sources). We present a new mini-halo detection hosted by MACS J2140.2-2339, having flux density S1.28 GHz = 2.61 ± 0.31
mJy, average diameter 296 kpc, and α1.5 GHz
1 GHz = 1.21 ± 0.36. We also found a ∼100 kpc southern extension to the ACO 3444
mini-halo which was not detected in previous VLA L-band observations. Our description of MeerKAT wide-field, wide-band
data reduction will be instructive for conducting further mini-halo science