1,721,120 research outputs found
Requirement analysis and sensor specifications – First version
Full text linkIn this first version of the deliverable, we make the following contributions: to design the
WEKIT capturing platform and the associated experience capturing API, we use a
methodology for system engineering that is relevant for different domains such as: aviation,
space, and medical and different professions such as: technicians, astronauts, and medical
staff. Furthermore, in the methodology, we explore the system engineering process and how
it can be used in the project to support the different work packages and more importantly
the different deliverables that will follow the current.
Next, we provide a mapping of high level functions or tasks (associated with experience
transfer from expert to trainee) to low level functions such as: gaze, voice, video, body
posture, hand gestures, bio-signals, fatigue levels, and location of the user in the
environment. In addition, we link the low level functions to their associated sensors.
Moreover, we provide a brief overview of the state-of-the-art sensors in terms of their
technical specifications, possible limitations, standards, and platforms.
We outline a set of recommendations pertaining to the sensors that are most relevant for
the WEKIT project taking into consideration the environmental, technical and human
factors described in other deliverables. We recommend Microsoft Hololens (for Augmented
reality glasses), MyndBand and Neurosky chipset (for EEG), Microsoft Kinect and Lumo Lift
(for body posture tracking), and Leapmotion, Intel RealSense and Myo armband (for hand
gesture tracking). For eye tracking, an existing eye-tracking system can be customised to
complement the augmented reality glasses, and built-in microphone of the augmented
reality glasses can capture the expert’s voice. We propose a modular approach for the design
of the WEKIT experience capturing system, and recommend that the capturing system
should have sufficient storage or transmission capabilities.
Finally, we highlight common issues associated with the use of different sensors. We
consider that the set of recommendations can be useful for the design and integration of the
WEKIT capturing platform and the WEKIT experience capturing API to expedite the time
required to select the combination of sensors which will be used in the first prototype.WEKI
Insights from a pseudospectral study of a potentially singular solution of the three-dimensional axisymmetric incompressible Euler equation
Full text linkWe develop a Fourier-Chebyshev pseudospectral direct numerical simulation
(DNS) to examine a potentially singular solution of the radially bounded,
three-dimensional (3D), axisymmetric Euler equations [G. Luo and T.Y. Hou,
Proc. Natl. Acad. Sci. USA, 111.36 (2014)]. We demonstrate that: (a) the time
of singularity is preceded, in any spectrally truncated DNS, by the formation
of oscillatory structures called tygers, first investigated in the
one-dimensional (1D) Burgers and two-dimensional (2D) Euler equations; (b) the
analyticity-strip method can be generalized to obtain an estimate for the
(potential) singularity time.Comment: 17 pages. 13 figure
Towards three-dimensional visual saliency
Full text linkA salient image region is defined as an image part that is clearly different from its surround in terms of a number of attributes. In bottom-up processing, these attributes are defined as: contrast, color difference, brightness, and orientation. By measuring these attributes, visual saliency algorithms aim to predict the regions in an image that would attract our attention under free viewing conditions, i.e., when the observer is viewing an image without a specific task such as searching for an object. To quantify the interesting locations in a scene, the output of the visual saliency algorithms is usually expressed as a two dimensional gray scale map where the brighter regions correspond to the highly salient regions in the original image. In addition to advancing our understanding of human visual system, visual saliency models can be used for a number of computer vision applications. These applications include: image compression, computer graphics, image matching & recognition, design, and human-computer interaction.
In this thesis the main contributions can be outlined as: first, we present a method to inspect the performance of Itti’s classic saliency algorithm in separating the salient and non-salient image locations. Based on our results we observed that, although the saliency model can provide a good discrimination for the highly salient and non-salient regions, there is a large overlap between the locations that lie in the middle range of saliency. Second, we propose a new bottom-up visual saliency model for static two-dimensional images. In our model, we calculate saliency by using the transformations associated with the dihedral group D4. Our results suggest that the proposed saliency model outperforms many state-of-the-art saliency models. By using the proposed methodology, our algorithm can be extended to calculate saliency in three-dimensional scenes, which we intend to implement in the future. Third, we propose a way to perform statistical analysis of the fixations data from different observers and different images. Based on the analysis, we present a robust metric for judging the performance of the visual saliency algorithms. Our results show that the proposed metric can indeed be used to alleviate the problems pertaining to the evaluation of saliency models. Four, we introduce a new approach to compress an image based on the salient locations predicted by the saliency models. Our results show that the compressed images do not exhibit visual artifacts and appear to be very similar to the originals. Five, we outline a method to estimate depth from eye fixations in three-dimensional virtual scenes that can be used for creating so-called gaze maps for three-dimensional scenes. In the future, this can be used as ground truth for judging the performance of saliency algorithms for three-dimensional images.
We believe that our contributions can lead to a better understanding of saliency, address the major issues associated with the evaluation of saliency models, highlight on the contribution of top-down and bottom-up processing based on the analysis of a comprehensive eye tracking dataset, promote use of human vision steered image processing applications, and pave the way for calculating saliency in three-dimensional scenes.PhD i informasjonsteknologiPhD in Information Technolog
Cloud-assisted trajectory data management and analysis
No full textMassive trajectory data with spatio-temporal information are generated from various devices everyday. Due to a wide variety of devices and data collection methods, these data differ in terms of frequency and precision, which brings challenges to data management and analysis. This paper presents TrajMan, a cloud-assisted framework for trajectory data management and analysis, which adds an edge layer between clients and cloud servers. With the assistance of edge devices, TrajMan supports fast data acquisition of extensive trajectory data, and reduces the WAN bandwidth and computation overhead for cloud servers by calibrating and compressing data locally. Cloud servers focus on data interpolation based on trajectory similarity to handle data in various frequencies, deriving more accurate trajectory features. To demonstrate the feasibility and performance of TrajMan, a preliminary case study of commute behavior analysis is conducted using real dataset, which shows 88% of the calculated commute distance has the relative deviation less than 20% and 80% of the calculated commute time deviates less than 10 minutes
Preparation and Characterization of SrFe12O19/ Ba2Co2Fe12O22 Composite Hexaferrite
No full textIn the present work, composites of SrFe12O19 (SrM)/Ba2Co2Fe12O22 (Co2Y) in different weight ratio (98/2, 96/4, 94/6, 92/8) were prepared. Their structural, morphological and magnetic properties were investigated using various techniques; viz. X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Raman Spectroscopy and Vibrating Sample Magnetometer (VSM). X-ray diffraction pattern confirmed the co-existence of both phases in composites which is also supported by Raman analysis. The magnetic measurements show non-linear rise in saturation magnetization with the Co2Y content, while the coercivity drastically decreases. Smooth demagnetization curve of sintered composites confirmed the well-exchange coupling between M-Y phases within the studied composition range
Mechanosynthesis and Characterization of Bi1-xGdxFeO3 Multiferroic Materials
No full textM.Tech. (Materials Science and Metallurgical Engineering)In the Present work multiferroic materials BiFeO3 were synthesized by high energy ball milling (HEBM) followed by thermal annealing at various temperatures. Further the effect of Gd substitution for Bi was investigated. The concentration of Gd was varied in the range of x=0.0 – 0.20). Phase characterization was carried out by X-ray diffraction. It is found that with increasing Gd content the impurity phase is decreased and single BiFeO3 phase is found at Gd (x = 0.1). Further increase in Gd content from x = 0.1 to 0.2 the impurity phase increases. The room temperature dielectric properties of pure and substituted BiFeO3 were measured in the frequency range from 20 Hz to 1MHz using LCR meter. For all studied samples dielectric constant increased from 110 (x=0.0) to 250 (x=0.10) and then decreases. The dielectric loss found to be more for pure BiFeO3 as compared to Bi1-xGdxO3. The P-E loops are also shows that the maximum polarization is in Bi0.9Gd0.1FeO3 as we increase the percent of Gd in Bi site the polarization becomes decrease. Scanning electron micrograph of Bi1-xGdxFeO¬3 (x=0.0, 0.1, 0.2) sintered sample shows that as we increase the concentration of Gd the grain size decrease. The grain shape is also changed with doping.SPM
Preparation and Characterization of Barium Hexaferrite Thin Films
No full textIn recent years, BaM (BaFe12O19) are the most interesting topic in the research because of its application in magnetic recording media, microwave devices and millimeter wave devices. It shows high resistivity, high chemical stability andgood magnetic properties. Recently, the focus of the researcher has been laid to the development of thin and thick films, owing to its versatile above mentioned properties. In the present work, BaFe12O19 thin films are prepared by magnetron sputtering technique. The main focus was to understand the effect of deposition time and annealing temperature on the structural and magnetic properties of BaFe12O19 thin films
Effect of the Particle Size on the Magnetic Properties of Barium Hexaferrite Bonded Magnets
No full textIn the present work barium ferrite compression bonded magnet with different particle size were prepared. To start this barium hexaferrite powder was prepared by solid state synthesis method. The calcined powder milled for different time to obtain the powder of different size. The chosen ball milling times were 1 h, 2 h, 3 h and 4 h. The particle size distribution was studied by mechanical sieving of powder. The prepared powders were mixed with epoxy resin and pressed in cylindrical die using hydraulic press. Phase and microstructural characterization was carried out by X-ray diffractometer and scanning electron microscope. XRD pattern shows the single phase barium hexaferrite. It is found that with increasing milling time the crystallite size decreases. From the SEM images it is found that the average particle size of powder decreases from 0.7µm to 0.5µm as the milling time increases. The magnetic properties were measured by vibration sample magnetometer. The result shows as the milling time increases the coercivity increases. The saturation magnetization remains same for all the bonded magnets
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