3,441 research outputs found
Automobile air bag inflation system based on fast combustion reaction
Current automobile air bag inflator technology is complex, expensive and environmentally unsafe. A new and novel air bag inflator based on fast combustion reactions of methane-oxygen mixtures has been developed and studied. The thermodynamics and mass flow parameters of this new inflator have been modeled and found to be in agreement with experimental results.
The performance of the fast combustion inflator was evaluated in terms of pressure-time relationships inside the inflator and in a receiving tank simulating an air bag as well as the temperature-time relationship in the tank.
In order to develop this fast combustion inflator, several critical issues were studied and evaluated. These included the effects of stoichiometry, initial mixture pressure and extreme hot and cold conditions. Other design and practical parameters, such as burst disk thickness and type, ignition device, tank purging gas, concentration of carbon monoxide produced and severity of temperature in the tank were also studied and optimized. Several inflator sizes were investigated and found to meet most of the requirements for a successful air bag inflator.
A theoretical and integrated model has been developed to simulate the transient pressure and temperature as well as the mass flow rate from the inflator to the tank. The model is based on the change in the internal energy inside the inflator and the receiving tank as the mass flows from the inflator to the tank. The model utilizes the Chemical Equilibrium Compositions and Applications code developed by NASA to estimate the equilibrium conditions in the inflator. A large volume of experimental results made at different conditions were found to be in agreement with the integrated model.
The fast combustion inflator developed during this research is simple in principle and construction and is environmentally attractive
Expressive Talking Head Video Encoding in StyleGAN2 Latent-Space
While the recent advances in research on video reenactment have yielded
promising results, the approaches fall short in capturing the fine, detailed,
and expressive facial features (e.g., lip-pressing, mouth puckering, mouth
gaping, and wrinkles) which are crucial in generating realistic animated face
videos. To this end, we propose an end-to-end expressive face video encoding
approach that facilitates data-efficient high-quality video re-synthesis by
optimizing low-dimensional edits of a single Identity-latent. The approach
builds on StyleGAN2 image inversion and multi-stage non-linear latent-space
editing to generate videos that are nearly comparable to input videos. While
existing StyleGAN latent-based editing techniques focus on simply generating
plausible edits of static images, we automate the latent-space editing to
capture the fine expressive facial deformations in a sequence of frames using
an encoding that resides in the Style-latent-space (StyleSpace) of StyleGAN2.
The encoding thus obtained could be super-imposed on a single Identity-latent
to facilitate re-enactment of face videos at . The proposed framework
economically captures face identity, head-pose, and complex expressive facial
motions at fine levels, and thereby bypasses training, person modeling,
dependence on landmarks/ keypoints, and low-resolution synthesis which tend to
hamper most re-enactment approaches. The approach is designed with maximum data
efficiency, where a single latent and 35 parameters per frame enable
high-fidelity video rendering. This pipeline can also be used for puppeteering
(i.e., motion transfer).Comment: The project page is located at
https://trevineoorloff.github.io/ExpressiveFaceVideoEncoding.io
One-Shot Face Video Re-enactment using Hybrid Latent Spaces of StyleGAN2
While recent research has progressively overcome the low-resolution
constraint of one-shot face video re-enactment with the help of StyleGAN's
high-fidelity portrait generation, these approaches rely on at least one of the
following: explicit 2D/3D priors, optical flow based warping as motion
descriptors, off-the-shelf encoders, etc., which constrain their performance
(e.g., inconsistent predictions, inability to capture fine facial details and
accessories, poor generalization, artifacts). We propose an end-to-end
framework for simultaneously supporting face attribute edits, facial motions
and deformations, and facial identity control for video generation. It employs
a hybrid latent-space that encodes a given frame into a pair of latents:
Identity latent, , and Facial deformation latent,
, that respectively reside in the and spaces of
StyleGAN2. Thereby, incorporating the impressive editability-distortion
trade-off of and the high disentanglement properties of . These hybrid
latents employ the StyleGAN2 generator to achieve high-fidelity face video
re-enactment at . Furthermore, the model supports the generation of
realistic re-enactment videos with other latent-based semantic edits (e.g.,
beard, age, make-up, etc.). Qualitative and quantitative analyses performed
against state-of-the-art methods demonstrate the superiority of the proposed
approach.Comment: The project page is located at
https://trevineoorloff.github.io/FaceVideoReenactment_HybridLatents.io
COVID-VTS: Fact Extraction and Verification on Short Video Platforms
We introduce a new benchmark, COVID-VTS, for fact-checking multi-modal
information involving short-duration videos with COVID19- focused information
from both the real world and machine generation. We propose, TwtrDetective, an
effective model incorporating cross-media consistency checking to detect
token-level malicious tampering in different modalities, and generate
explanations. Due to the scarcity of training data, we also develop an
efficient and scalable approach to automatically generate misleading video
posts by event manipulation or adversarial matching. We investigate several
state-of-the-art models and demonstrate the superiority of TwtrDetective.Comment: 11 pages, 5 figures, accepted to EACL202
Electrodermal Activity: Simultaneous Recordings
Electrodermal activity (EDA) is a sensitive measure of the sympathetic nervous system activity. It is used to describe changes in the skin electrical properties. This chapter aimed to show advantages of simultaneous recordings of EDA parameters at the same skin site over other recordings. The literature databases, Web of Science and Google Scholar, were searched using terms like “electrodermal activity,” “sequential recording,” “simultaneous recording,” “skin conductance,” “skin potential,” and “skin susceptance.” Articles that include sequential and/or simultaneous recording of EDA parameters were analyzed. The chapter presents a description of the oldest and current methods used for recording EDA parameters and an explanation of the newest techniques used in EDA researches. Although sequential recordings are predominant and widely spreading, much effort has been made to simultaneously record skin conductance (SC) and skin potential (SP), and recently researchers realized the capability of simultaneously recording SC, SP, and skin susceptance (SS) at the same skin site. The advantage of simultaneous over the sequence measurements is that the latter must be manually time realigned when measured by different instruments, which means it is time-consuming. Although the simultaneous measurements are used exclusively for research purposes at this stage, this may open horizons in the modern trends of psychophysiology applications in the near future
Bioelectrical impedance method for assessing later body-composition considering the influence of breastfed on gender
Purpose: to study the effect of breastfeeding on body composition in both male and female via bioimpedance analysis method. analysis methods.
Methods: we determined the body composition (body fat percentage, muscle mass percentage, and bone mass percentage) by bioimpedance analysis methods in 60 adults (31 male and 29 female) who were classified as underweight, normal and overweight subjects aged 20 years old. Average BMI was 21.4 Kg/ m2 which calculated by traditional formula.
Findings: The differences in %BF assessed using bipolar analyzers were significantly higher for female than male. There was a significant difference (
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