531 research outputs found
A Mobile Geo-Communication Dataset for Physiology-Aware DASH in Rural Ambulance Transport
Use of telecommunication technologies for remote, continuous monitoring of
patients can enhance effectiveness of emergency ambulance care during transport
from rural areas to a regional center hospital. However, the communication
along the various routes in rural areas may have wide bandwidth ranges from 2G
to 4G; some regions may have only lower satellite bandwidth available.
Bandwidth fluctuation together with real-time communication of various clinical
multimedia pose a major challenge during rural patient ambulance transport.;
AB@The availability of a pre-transport route-dependent communication bandwidth
database is an important resource in remote monitoring and clinical multimedia
transmission in rural ambulance transport. Here, we present a geo-communication
dataset from extensive profiling of 4 major US mobile carriers in Illinois,
from the rural location of Hoopeston to the central referral hospital center at
Urbana. In collaboration with Carle Foundation Hospital, we developed a
profiler, and collected various geographical and communication traces for
realistic emergency rural ambulance transport scenarios. Our dataset is to
support our ongoing work of proposing "physiology-aware DASH", which is
particularly useful for adaptive remote monitoring of critically ill patients
in emergency rural ambulance transport. It provides insights on ensuring higher
Quality of Service (QoS) for most critical clinical multimedia in response to
changes in patients' physiological states and bandwidth conditions. Our dataset
is available online for research community.Comment: Proceedings of the 8th ACM on Multimedia Systems Conference
(MMSys'17), Pages 158-163, Taipei, Taiwan, June 20 - 23, 201
Association Between Periodontal Disease and Atherosclerotic Cardiovascular Diseases: Revisited
An automated and improved methodology to retrieve long-time series of evapotranspiration based on remote sensing and reanalysis data
The large-scale quantification of accurate evapotranspiration (ET) time series has substantially been developed in recent decades using automated approaches based on remote sensing data. However, there are still several model-related uncertainties that require precise assessment. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) and meteorological data from the Global Land Data Assimilation System (GLDAS) were used to estimate long-term daily actual ET based on three endmember selection procedures: two land cover-based models, one with (WF) and the other without (WOF) morphological functions, and the Allen method (with the default percentiles) for 2270 Landsat images. Models were evaluated for 23 flux tower sites with four main vegetation cover types as well as different climate types. Results showed that endmember selection with morphological functions (WF_ET) generally performed better than the other endmember approaches. Climate-based classification assessment provided the clearest discrimination between the performance of the different endmember selection approaches for the humid category. For humid zones, the land cover-based methods, especially WF, appropriately outperformed Allen. However, the performance of the three approaches was similar for sub-humid, semi-arid and arid climates together; the Allen approach was therefore recommended to avoid the need for dependency on land cover maps. Tower-by-tower validation also showed that the WF approach performed best at 12 flux tower sites, the WOF approach best at 5 and the Allen approach best at 6, suggesting that the use of land cover maps alone does not explain the differences between the performance of the land cover-based models and the Allen approach. Additionally, the satisfactory error metrics results when comparing the EC estimations with EC measurements, with root mean square error (RMSE) ≈ 0.91 and 1.59 mm·day−1, coefficient of determination (R2) ≈ 0.71 and 0.41, and bias percentage (PBias) ≈ 2% and 60% for crop and non-crop flux tower sites, respectively, supports the use of GLDAS meteorological forcing datasets with the different automated ET estimation approaches. Overall, given that the thorough evaluation of different endmember selection approaches at large scale confirmed the validity of the WF approach for different climate and land cover types, this study can be considered an important contribution to the global retrieval of long time series of ETinfo:eu-repo/semantics/publishedVersio
Une approche bayésienne pour les problèmes inverses en imagerie Radar à Synthèse d'Ouverture
L'imagerie Radar à Synthèse d'Ouverture (RSO) est une technique bien connue dans les domaines de télédétection, de surveillance aérienne, de géologie et de cartographie. Obtenir des images de haute résolution malgré la présence de bruit, tout en prenant en compte les caractéristiques des cibles dans la scène observée, les différents incertitudes de mesure et les erreurs resultantes de la modélisation, devient un axe de recherche très important.Les méthodes classiques, souvent fondées sur i) la modélisation simplifiée de la scène ; ii) la linéarisation de la modélisation directe (relations mathématiques liant les signaux reçus, les signaux transmis et les cibles) simplifiée ; et iii) l'utilisation de méthodes d'inversion simplifiées comme la Transformée de Fourier Inverse (TFI) rapide, produisent des images avec une résolution spatiale faible, peu robustes au bruit et peu quantifiables (effets des lobes secondaires et bruit du speckle).Dans cette thèse, nous proposons d'utiliser une approche bayésienne pour l'inversion. Elle permettrais de surmonter les inconvénients mentionnés des méthodes classiques, afin d'obtenir des images stables de haute résolution ainsi qu'une estimation plus précise des paramètres liés à la reconnaissance de cibles se trouvant dans la scène observée.L'approche proposée est destinée aux problèmes inverses de l'imagerie RSO mono-, bi-, et multi- statique ainsi que l'imagerie des cibles à micromouvement. Les a priori appropriés de modélisation permettant d'améliorer les caractéristiques des cibles pour des scènes de diverses natures seront présentées. Des méthodes d'estimation rapides et efficaces utilistant des a priori simples ou hiérarchiques seront développées. Le problème de l'estimation des hyperparameters sera galement traité dans le cadre bayésin. Les résultats relatifs aux données synthétiques, expérimentales et réelles démontrent l'efficacité de l'approche proposée.Synthetic Aperture Radar (SAR) imaging is a well-known technique in the domain of remote sensing, aerospace surveillance, geography and mapping. To obtain images of high resolution under noise, taking into account of the characteristics of targets in the observed scene, the different uncertainties of measure and the modeling errors becomes very important.Conventional imaging methods are based on i) over-simplified scene models, ii) a simplified linear forward modeling (mathematical relations between the transmitted signals, the received signals and the targets) and iii) using a very simplified Inverse Fast Fourier Transform (IFFT) to do the inversion, resulting in low resolution and noisy images with unsuppressed speckles and high side lobe artifacts.In this thesis, we propose to use a Bayesian approach to SAR imaging, which overcomes many drawbacks of classical methods and brings high resolution, more stable images and more accurate parameter estimation for target recognition.The proposed unifying approach is used for inverse problems in Mono-, Bi- and Multi-static SAR imaging, as well as for micromotion target imaging. Appropriate priors for modeling different target scenes in terms of target features enhancement during imaging are proposed. Fast and effective estimation methods with simple and hierarchical priors are developed. The problem of hyperparameter estimation is also handled in this Bayesian approach framework. Results on synthetic, experimental and real data demonstrate the effectiveness of the proposed approach.PARIS11-SCD-Bib. électronique (914719901) / SudocSudocFranceF
Coupled Eulerian-Lagrangian Debris Flow Model with Flexible Barrier
Natural hazards such as large debris flow events can have catastrophic effects on the environment and critical infrastructure, posing a significant threat to human life. Debris flows often exhibit high velocity, high-pressure discharges due to their bulk volume, and the capacity to transport considerable volumes of large rocks, boulders, and woody debris. Although debris flow run-out simulations are commonly performed using hydraulic modelling software, these environments are seldom capable of assessing the interaction between the debris fluid, transported material, and protective structures. In this research, large deformation numerical models are calibrated using input parameters from hydraulic modelling software. Due to the computational cost of the large deformation models involving fluid-solid-structure simulation with flexible net barriers, an equivalent stiffness method is implemented to provide comparable performance through a membrane structure. The Coupled Eulerian-Lagrangian Finite Element method is used to model the impact forces of rocky boulders on the membrane, exhibiting damage characteristics consistent with flexible ring-net protective structures. The Coupled Eulerian-Lagrangian model results highlight the performance of the simplified membrane, as shown through a benchmark simulation of debris flow with boulders
Surface analysis of conversion coating of ASTM A 516
Surface engineering is a vital aspect of manufacturing industries owing to its benefits both in surface protection and aesthetics. It has been extensively used in various industries to guard against corrosion which is a naturally occurring and highly undesirable phenomenon. Present research has endeavored to analyze protection of ASTM A516 (Grade 70) from corrosion through surface engineering. Different methods of surface treatment and conversion coating were carried out to efficiently enhance corrosive protection. Comparative analysis of various samples was conducted to analyze their ability to resist corrosion. Samples with surface treatment followed by conversion coating were found to be effective even against 0.7% aqueous sulfuric acid with no significant cracks in the coating layer. On the other hand, conversion coated only samples showed protection against 0.35% acid. The coating of conversion coated only samples was found to have gaps/ cracks as indicated by 3% Cupric Sulfate whereas no such gaps were found in surface treated samples. Optical microscopy identified a more uniform coating thickness for surface treated samples in comparison with conversion coated only samples. In depth morphology analysis using SEM highlighted that surface treated samples had low porosity preventing the corrosion elements to reach the substrate thereby implementing higher corrosion potential
Acetic acid separation from anaerobically treated palm oil mill effluent by ion exchange resins for the production of polyhydroxyalkanoate by Alcaligenes eutrophus
Separation of acetic acid from palm oil mill effluent (POME) to increase its concentration by an anion exchange resin was examined as a preliminary study for its recovery from POME that had been anaerobically treated by sludge from a palm oil mill. This paper concerns the acetic acid thus separated for producing bacterial polyhydroxyalkanoate (PHA) by Alcaligenes eutrophus. It was found that sludge particles in POME strongly inhibited the adsorption of acetic acid on the anion exchange resin. Removing the sludge particles from the POME facilitated the separation of acetic acid from the POME efficiently. The concentrated acetic acid thus obtained from anaerobically treated POME could be used as a substrate in the fed-batch production of polyhydroxyalkanoate by Alcaligenes eutrophus
Linking Chromosomal Silencing With Xist Expression From Autosomal Integrated Transgenes
Xist is the master regulator of X-Chromosome Inactivation (XCI), the mammalian dosage compensation mechanism that silences one of the two X chromosomes in a female cell. XCI is established during early embryonic development. Xist transgene (Tg) integrated into an autosome can induce transcriptional silencing of flanking genes; however, the effect and mechanism of Xist RNA on autosomal sequence silencing remain elusive. In this study, we investigate an autosomal integration of Xist Tg that is compatible with mouse viability but causes male sterility in homozygous transgenic mice. We observed ectopic Xist expression in the transgenic male cells along with a transcriptional reduction of genes clustered in four segments on the mouse chromosome 1 (Chr 1). RNA/DNA Fluorescent in situ Hybridization (FISH) and chromosome painting confirmed that Xist Tg is associated with chromosome 1. To determine the spreading mechanism of autosomal silencing induced by Xist Tg on Chr 1, we analyzed the positions of the transcriptionally repressed chromosomal sequences relative to the Xist Tg location inside the cell nucleus. Our results show that the transcriptionally repressed chromosomal segments are closely proximal to Xist Tg in the three-dimensional nucleus space. Our findings therefore support a model that Xist directs and maintains long-range transcriptional silencing facilitated by the three-dimensional chromosome organization
Numerical study of heat transfer and viscous flow in a dual rotating extendable disk system with a non-Fourier heat flux model
Nonlinear, steady-state, viscous flow and heat transfer between two stretchable rotating disks spinning at dissimilar velocities is studied with a non-Fourier heat flux model. A non-deformable porous medium is intercalated between the disks and the Darcy model is employed to simulate matrix impedance. The conservation equations are formulated in a cylindrical coordinate system and via the Von Karman transformations are rendered into a system of coupled, nonlinear ordinary differential equations. The emerging boundary value problem is controlled by number of dimensionless dimensionless parameters i.e. Prandtl number, upper disk stretching, lower disk stretching, permeability, non-Fourier thermal relaxation and relative rotation rate parameters. A perturbation solution is developed and the impact of selected parameters on radial and tangential velocity components, temperature, pressure, lower disk radial and tangential skin friction components and surface heat transfer rate are visualized graphically. Validation of solutions with the homotopy analysis method is included. Extensive interpretation of the results is presented which are relevant to to rotating disk bioreactors in chemical engineering
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