A slip model for micro/nano gas flows induced by body forces

A slip model for gas flows in micro/nano-channels induced by external body forces is derived based on Maxwell's collision theory between gas molecules and the wall. The model modifies the relationship between slip velocity and velocity gradient at the walls by introducing a new parameter in addition to the classic Tangential Momentum Accommodation Coefficient. Three-dimensional Molecular Dynamics simulations of helium gas flows under uniform body force field between copper flat walls with different channel height are used to validate the model and to determine this new parameter

Adult-perpetrated Animal Abuse: Development of a Proclivity Scale

There is a clear discrepancy in the reporting of animal cruelty complaints, prosecutions and convictions suggesting that any prevalence figures of abuse are significant under-representations. Therefore, it can be inferred that there is a large number of animal abusers who are unapprehended. Currently there is no validated tool that assesses the proclivity or propensity to engage in animal abuse amongst members of the general public. Such a tool would enable researchers to study individuals who may think like animal abusers or may be unapprehended offenders themselves. This paper presents the newly developed Animal Abuse Proclivity Scale (AAPS) and some preliminary findings. The results from our two studies show that: (1) the psychometric properties of the AAPS indicate that the scale is a highly reliable measure; (2) the AAPS relates to measures assessing offence-supportive attitudes and reflects the gender differences seen in the literature; and (3) the AAPS demonstrates cross-national validity. These findings support that the AAPS, similar to other offending proclivity measures, is a tool that can be used to examine the factors most related to animal abuse propensity. We discuss how the AAPS can contribute to future developments in theory and practice in the field

Liquid oxygen/liquid hydrogen boost/vane pump for the advanced orbit transfer vehicles auxiliary propulsion system

A rotating, positive displacement vane pump with an integral boost stage was designed to pump saturated liquid oxygen and liquid hydrogen for auxiliary propulsion system of orbit transfer vehicle. This unit is designed to ingest 10% vapor by volume, contamination free liquid oxygen and liquid hydrogen. The final pump configuration and the predicted performance are included

Image segmentation for surface material-type classification using 3D geometry information

This paper describes a novel approach for the segmentation of complex images to determine candidates for accurate material-type classification. The proposed approach identifies classification candidates based on image quality calculated from viewing distance and angle information. The required viewing distance and angle information is extracted from 3D fused images constructed from laser range data and image data. This approach sees application in material-type classification of images captured with varying degrees of image quality attributed to geometric uncertainty of the environment typical for autonomous robotic exploration. The proposed segmentation approach is demonstrated on an autonomous bridge maintenance system and validated using gray level co-occurrence matrix (GLCM) features combined with a naive Bayes classifier. Experimental results demonstrate the effects of viewing distance and angle on classification accuracy and the benefits of segmenting images using 3D geometry information to identify candidates for accurate material-type classification. ©2010 IEEE

Surface-type classification using RGB-D

This paper proposes an approach to improve surface-type classification of images containing inconsistently illuminated surfaces. When a mobile inspection robot is visually inspecting surface-types in a dark environment and a directional light source is used to illuminate the surfaces, the images captured may exhibit illumination variance that can be caused by the orientation and distance of the light source relative to the surfaces. In order to accurately classify the surface-types in these images, either the training image dataset needs to completely incorporate the illumination variance or a way to extract color features that can provide high classification accuracy needs to be identified. In this paper diffused reflectance values are extracted as new color features to classifying surface-types. In this approach, Red, Green, Blue-Depth (RGB-D) data is collected from the environment, and a reflectance model is used to calculate a diffused reflectance value for a pixel in each Red, Green, Blue (RGB) color channel. The diffused reflectance values can be used to train a multiclass support vector machine classifier to classify surface-types. Experiments are conducted in a mock bridge maintenance environment using a portable RGB-Depth sensor package with an attached light source to collect surface-type data. The performance of a classifier trained with diffused reflectance values is compared against classifiers trained with other color features including RGB and Lcolor spaces. Results show that the classifier trained with the diffused reflectance values can achieve consistently higher classification accuracy than the classifiers trained with RGB and Lab features. For test images containing a single surface plane, diffused reflectance values consistently provide greater than 90% classification accuracy; and for test images containing a complex scene with multiple surface-types and surface planes, diffused reflectance values are shown to provide an increase in overall accuracy over RGB and Lab by 49.24% and 13.66%, respectively. © 2013 IEEE

Power allocation for multiband coded OFDM systems with limited feedback

In this paper, we study the power allocation for multiband coded OFDM systems. With limited feedback, we propose an effective power allocation method across OFDM bands to maximize the throughput and achieve the quality of service target. To facilitate the proposed method, two optimization algorithms based on greedy and dynamic programming principles are discussed. The trade-off between performance and complexity is provided. Simulation results show that the proposed power allocation mechanism allows a signal to noise ratio gain of 2 dB at a goodput of 2.5 bit per second per Hz over the multiband OFDM systems with equal power allocation

Digital twin for 5G and beyond

Although many countries have started the initial phase of rolling out 5G, it is still in its infancy with researchers from both academia and industry facing the challenges of developing to its full potential. With the support of Artificial Intelligence, development of digital transformation through the notion of a ‘Digital Twin’ has been taking off in many industries such as smart manufacturing, oil & gas, constructions, bio-engineering, and automotive. However, Digital Twins remain relatively new for 5G networks, despite the obvious potential in helping develop and deploy the complex 5G environment. This paper looks into these topics and discusses how Digital Twin could be a powerful tool to fulfil the potentials of 5G networks and beyond