Defense Research and Development Canada
Defense Research and Development Canada
News Article | December 1, 2016
High-resolution brain scans analyzed by machine learning algorithms could determine whether a patient has a concussion, according to a new study published in PLOS Computational Biology. Currently, doctors diagnose concussions according to patient-reported symptoms, which can be challenging and inefficient. Previous studies have used high-resolution imaging to show that concussions cause changes in communication between different brain areas. However, these studies have typically only looked at average changes across groups of patients. Vasily Vakorin, now of Simon Fraser University, British Columbia, and colleagues (from the Hospital for Sick Children, Toronto and Defense Research and Development Canada) investigated whether high-resolution imaging could be combined with machine learning algorithms to detect concussions in the brains of individual patients. The researchers scanned the brains of men with and without concussion using magnetoencephalography (MEG), which records brain activity at fast time scales. MEG imaging showed that patients with concussions had distinctive changes in communication among areas of their brains. Then, by employing machine learning algorithms, the scientists were able to use individual brain scans to work backwards and predict whether a given patient had a concussion or not. They were able to detect concussions with 88% accuracy. This approach also accurately predicted the severity of symptoms reported by individual patients. "Changes in communication between brain areas, as detected by magnetoencephalography, allowed us to detect concussion from individual scans, in situations wherein typical clinical imaging tools such as MRI or CT fail," says study coauthor Sam Doesburg. Future research could refine understanding of the specific neural changes associated with concussions in order to improve detection, inform treatment, and monitor recovery. In your coverage please use this URL to provide access to the freely available article in PLOS Computational Biology: http://journals. Funding: This work was supported by the Canadian Forces Health Services and funding from Defence Research and Development Canada (DRDC) (contract # W7719-135182/001/TOR) to MJT and EWP. The funders had no role in study. Competing Interests: The authors have declared that no competing interests exist.
Liu Z.,National Research Council Canada |
Mrad N.,Defense Research and Development Canada
IEEE Sensors Journal | Year: 2013
The application of structural health monitoring (SHM) often employs multiple sensors to monitor the state of health and usage of the structures. The fault of any sensor may lead to an inaccurate or even incorrect inference with the collected sensor data, which will accordingly create a negative impact on higher-level decisions for maintenance and services. Thus, sensor validation becomes a critical process to the performance of the whole SHM system. This paper presents the use of Bayesian belief network to validate the reading of strain gauges on an aluminum plate for loading monitoring. The Bayesian belief network is constructed with the training data. The factors investigated in this paper, which may affect the validation process, include sensor configuration, sensor redundancy, and sensor data range for the discretization. The feasibility of using a Bayesian belief network for SHM sensor validation is demonstrated with the experimental results. © 2001-2012 IEEE.
Liu H.,University of Western Ontario |
Zhang Y.,University of Western Ontario |
Li R.,University of Western Ontario |
Sun X.,University of Western Ontario |
Abou-Rachid H.,Defense Research and Development Canada
Journal of Nanoparticle Research | Year: 2012
Nitrogen-doped carbon nanotubes (CN x tubes) with nitrogen content of 7.6 at.% are synthesized on carbon papers. Thermal and chemical stability of the nanotubes are investigated by thermogravimetric analysis, differential scanning calorimetry and X-ray photoelectron spectroscopy techniques. The results indicate that the nitrogen can be firmly kept in the nanotubes after annealing at 300 °C in air. Under an argon atmosphere, the nitrogen would not release until 670°C, and half of the nitrogen incorporated is released after annealing at 700°C for 30 min. Chemical stability investigation indicates that the nitrogen incorporated in the nanotubes is very stable under the thermal and acid environment comparable to working condition of proton exchange membrane (PEM) fuel cells. Profile of the nitrogen species inside the nanotubes reveals that graphite-like nitrogen releases slower than any other kind of nitrogen in the nanotubes during the chemical stability measurement. These CN x tubes synthesized by this simple chemical vapor deposition method are expected to be suitable for many applications, such as PEM fuel cells that work under both thermal and corrosive conditions and some other mild thermal environments. © 2012 Springer Science+Business Media B.V.
Marier J.-S.,Numerica Technologies |
Rabbath C.-A.,Defense Research and Development Canada |
Lechevin N.,Defense Research and Development Canada
Proceedings of the American Control Conference | Year: 2011
One of the main hypotheses supporting the development of cooperative unmanned systems is that the deployment of mobile assets (sensors, weapons) in groups is expected to result in a more effective mission than if conducted with a single asset. Few researches have tackled the design of autonomous decision making for teaming UxVs (unmanned air and ground vehicles) operating under degraded conditions, even though it is common knowledge that real operations are more often than not conducted in less-than-ideal conditions. We consider a team of UxVs that have for mission to persistently monitor an area. We want to ensure they perform as best as possible assuming they are subject to a limited set of degraded conditions. We propose a model to account for variable sensor effectiveness as well as a method to optimize their placement based on a cost balancing heuristic. Numerical simulation suggests accounting for sensor effectiveness improves their placement. © 2011 AACC American Automatic Control Council.
Ross V.,AEREX Avionics Inc. |
Dion D.,Defense Research and Development Canada |
St-Germain D.,Defense Research and Development Canada
Applied Optics | Year: 2012
Radiometric images taken in mid-wave and long-wave infrared bands are used as a basis for validating a sea surface bidirectional reflectance distribution function (BRDF) being implemented into MODTRAN 5 (Berk et al. [Proc. SPIE 5806, 662 (2005)]). The images were obtained during the MIRAMER campaign that took place in May 2008 in the Mediterranean Sea near Toulon, France. When atmosphere radiances are matched at the horizon to remove possible calibration offsets, the implementation of the BRDF in MODTRAN produces good sea surface radiance agreement, usually within 2% and at worst 4% from off-glint azimuthally averaged measurements. Simulations also compare quite favorably to glint measurements. The observed sea radiance deviations between model and measurements are not systematic, and are well within expected experimental uncertainties. This is largely attributed to proper radiative coupling between the surface and the atmosphere implemented using the DISORT multiple scattering algorithm. © 2012 Optical Society of America.
Fikretoglu D.,Defense Research and Development Canada |
Fikretoglu D.,McGill University |
Liu A.,McGill University
Social Psychiatry and Psychiatric Epidemiology | Year: 2015
Purpose: Despite the availability of efficacious treatments, few individuals with a new-onset mental disorder access treatment in a timely manner. While barriers to mental health treatment have been studied among prevalent cases, few studies have focused specifically on incident cases. The purpose of the current study was to examine the prevalence and correlates of perceived barriers to mental health treatment among incident cases. Methods: Data came from the Canadian Community Health Survey, cycle 1.2 (CCHS 1.2), which represents a nationally representative sample of 36,984 Canadians. We used descriptive analyses to estimate the prevalence of different types of perceived barriers to treatment and logistic regression analyses to estimate the association between potential correlates and the probability of endorsing each type of barrier. Results: The most frequently reported type of barrier was acceptability. Coping efficacy and psychological well-being were negatively associated with the likelihood of reporting accessibility barriers. Education was negatively associated with reporting acceptability barriers but positively associated with reporting availability barriers. Conclusions: Among individuals with a recent disorder onset, acceptability barriers are the most frequently reported. Perceived accessibility barriers may be open to influence from current clinical functioning and current perceptions of internal coping resources. These findings contribute to an important discussion about the complexity of pathways to care and point to the need for comprehensive approaches to overcoming barriers to care. © 2014, Her Majesty the Queen in Right of Canada as represented by: Department of National Defence.
Levesque J.-C.,Defense Research and Development Canada |
Levesque J.-C.,Laval University |
Laurendeau D.,Laval University |
Mokhtari M.,Defense Research and Development Canada
Proceedings - IEEE Virtual Reality | Year: 2011
In this paper, a 3D bimanual gestural interface using data gloves is presented. We build upon past contributions on gestural interfaces and bimanual interactions to create an efficient and intuitive gestural interface that can be used in immersive environments. The proposed interface uses the hands in an asymmetric style, with the left hand providing the mode of interaction and the right hand acting at a finer level of detail. © 2011 IEEE.
Liang Y.,Royal Military College of Canada |
Pond G.,Defense Research and Development Canada
Proceedings - 2011 7th International Conference on Natural Computation, ICNC 2011 | Year: 2011
The aim of this study is to explore potential routing protocol for software development of MANET (Mobile Ad-hoc Network) peer-to-peer system which can be used for battle field radio communications. MANET consists of a number of mobile devices which communicate over radio, and a MANET with cell phones (MANET-WCP) is the physical infrastructure of the underlined research. One of the biggest challenges of this type of network is to find a route between a source node to a destination node via intermediate nodes with mobility. In this paper, we present a routing protocol using swarm intelligent heuristic (SIH) for MANET-WCP. We refer to the protocol as the Swap Intelligent Heuristic Associate Based Routing, i.e., SIH-ABR. The protocol replaces the route selection mechanism with ant colony optimization heuristic. The main objectives of this approach are: 1). to test the adaptation of SIH-ABR; 2). to verify the efficiency of service; 3). to explore its scalability with a larger number of nodes in a land battle scenario. © 2011 IEEE.
Bordeleau G.,INRS - Institute National de la Recherche Scientifique |
Martel R.,INRS - Institute National de la Recherche Scientifique |
Ampleman G.,Defense Research and Development Canada |
Thiboutot S.,Defense Research and Development Canada |
Poulin I.,Defense Research and Development Canada
Journal of Contaminant Hydrology | Year: 2012
The environmental fate of nitroglycerin (NG) in the unsaturated zone was evaluated in the context of double-base propellant residue deposition at anti-tank training ranges. Fresh propellant residues were collected during live anti-tank training. Surface soils, sub-surface soils and water samples from the unsaturated zone were collected at an active anti-tank range, and at a legacy site where NG-based propellants have been used. Results show that the residues are composed of intact propellant particles, as well as small quantities of NG, dinitroglycerin (DNG) and nitrate which are rapidly dissolved by precipitation, resulting in sporadic pulses of those compounds in water from the unsaturated zone after rain/snow melt events. The dissolved NG and DNG can be progressively degraded in the unsaturated zone, releasing nitrate as an end-product. Over a period of several years, small propellant particles located at the soil surface can be carried downward through the soil pore system by infiltration water, which explains the presence of NG in sub-surface soils at the legacy site, more than 35 years after site closure. NG is no longer leached from these old particles, therefore the detection of NG in sub-surface soils does not signify that groundwater is at risk of contamination by NG. © 2012 Elsevier B.V.
Bacciochini A.,University of Ottawa |
Radulescu M.I.,University of Ottawa |
Yandouzi M.,University of Ottawa |
Maines G.,University of Ottawa |
And 2 more authors.
Surface and Coatings Technology | Year: 2013
The present study deals with the use of the Cold Gas Dynamic Spray (Cold Spray) process to consolidate reactive materials with low porosity (up to 99.8% of the theoretical maximum density) and controllable shapes for potential near-net shape applications. The study focuses on the Al/CuO thermite mixture. The microstructure and mechanical properties (four-point bending and microhardness) of the consolidated samples were investigated while varying the spray process parameters, such as stand-off distance, propellant gas pressure and feedstock powder (fuel) particle size. The reactive mixture was successfully consolidated without the onset of the thermite reaction. The consolidated sample reactivity was addressed through flame propagation velocity measurements as a function of sample density. Results show a relation between the sample's porosity level and the flame propagation velocity. The reduction of porosity tends to decrease the flame speed from approximately 1400. mm/s at 20% density down to 150. mm/s at 100%. This indicates a transition from convection dominated energy transfer at low porosities to heat conduction dominated mechanism at vanishing porosities when gas percolation is not possible. © 2013 Elsevier B.V.