60419 research outputs found
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Incentive mechanisms for mobile data offloading through operator-owned WiFi access points
No full textDue to the explosive growth of mobile data traffic, it has become a common practice for Mobile Network Operators (MNOs, also known as operators or carriers) to utilize cellular and WiFi resources simultaneously through mobile data offloading. However, existing offloading technologies are mainly established between operators and third-party WiFi resources, which cannot reflect users dynamic traffic demands. Therefore, MNOs have to design an effective incentive framework, encouraging users to reveal their valuations on resources. In this paper, we propose a novel bid-based Heterogeneous Resources Allocation (HRA) framework. It can enable operators to efficiently utilize both cellular and operator-own WiFi resources simultaneously, where the decision cost of user is strictly controlled. Through auction-based mechanisms, it can achieve dynamic offloading with awareness of users valuations. And the operator-domain offloading effectively avoids anarchy brought by users selfishness and lack of information. More specifically, HRA-Profit and HRA-Utility, are proposed to achieve the maximal profit and social utility, respectively. addition, based on Stochastic Multi-Armed Bandit model, the newly proposed HRA-UCB-Profit and HRA-UCB-Utility are able to gain near-optimal profit and social utility under incomplete user context information. All mechanisms have been proven to be truthful and satisfy individual rationality, while the achieved profit of our mechanism is within a bounded difference from the optimal profit. In addition, the trace-based simulations and evaluations have demonstrated that HRA-Profit and HRA-Utility increase the profit and social utility by up to 40% and 47%, respectively, compared with benchmarks. And the cellular utilization rate is kept at a favorable level under the proposed mechanisms. HRA-UCB-Profit and HRA-UCB-Utility restrict pseudo-regret ratios under 20%
Learning to animate volumetric video.
No full text4D human performance capture aims to create volumetric representations of observed human subjects performing arbitrary motions with the ability to replay and render dynamic scenes with the realism of the recorded video. This representation has the potential to enable highly realistic content production for immersive virtual and augmented reality experiences. Human models are typically rendered using detailed, explicit 3D models, which consist of meshes and textures, and animated using tailored motion models to simulate human behaviour and activity. However, designing a realistic 3D human model is still a costly and laborious process. Hence, this work investigates techniques to learn models of human body shape and appearance, aiming to facilitate the generation of highly realistic human animation, and demonstrate its potential contributions, applications, and versatility.
The first contribution of this work is a skeleton driven surface registration approach to generate temporally consistent meshes from multi-view video of human subjects. 2D pose detections from multi-view video are used to estimate 3D skeletal pose on a per-frame basis, which allows a reference frame to match the pose estimation of other frames in a sequence. This allows an initial coarse alignment followed by a patch-based non-rigid mesh deformation to generate temporally consistent mesh sequences.
The second contribution presents techniques to represent human-like shape using a compressed learnt model from 4D volumetric performance capture data. Sequences of 4D dynamic geometry representing a human are encoded with a generative network into a compact space representation, whilst maintaining the original properties, such as surface non-rigid deformations. This compact representation enables synthesis, interpolation and generation of 3D shapes.
The third contribution is Deep4D generative network that is capable of compact representation of 4D volumetric video sequences from skeletal motion of people with two orders of magnitude compression. A variational encoder-decoder is employed to learn an encoded latent space that maps from 3D skeletal pose to 4D shape and appearance. This enable high-quality 4D volumetric video synthesis to be driven by skeletal animation.
Finally, this thesis introduces Deep4D motion graph to implicitly combine multiple captured motions in a unified representation for character animation from volumetric video, allowing novel character movements to be generated with dynamic shape and appearance detail. Deep4D motion graphs allow character animation to be driven by skeletal motion sequences providing a compact encoded representation capable of high-quality synthesis of the 4D volumetric video with two orders of magnitude compression
A Novel Approach to Atomistic Molecular Dynamics Simulation of Phenolic Resins Using Symthons
No full textMaterials science is beginning to adopt computational simulation to eliminate laboratory trial and error campaigns—much like the pharmaceutical industry of 40 years ago. To further computational materials discovery, new methodology must be developed that enables rapid and accurate testing on accessible computational hardware. To this end, the authors utilise a novel methodology concept of intermediate molecules as a starting point, for which they propose the term ‘symthon’a rather than conventional monomers. The use of symthons eliminates the initial monomer bonding phase, reducing the number of iterations required in the simulation, thereby reducing the runtime. A novel approach to molecular dynamics, with an NVT (Canonical) ensemble and variable unit cell geometry, was used to generate structures with differing physical and thermal properties. Additional script methods were designed and tested, which enabled a high degree of cure in all sampled structures. This simulation has been trialled on large-scale atomistic models of phenolic resins, based on a range of stoichiometric ratios of formaldehyde and phenol. Density and glass transition temperature values were produced, and found to be in good agreement with empirical data and other simulated values in the literature. The runtime of the simulation was a key consideration in script design; cured models can be produced in under 24 h on modest hardware. The use of symthons has been shown as a viable methodology to reduce simulation runtime whilst generating accurate models
The year in cardiology: aorta and peripheral circulation
No full textSimilar to previous years, 1–3 the current article reviews groundbreaking science published 2019 in the area of aortic and peripheral arterial
diseases (PAD) as well as venous thromboembolic disease (VTE)
that will affect our daily clinical practice. With the growing recognition of PAD, it will be necessary to consolidate imprecisions in terminology. Many are used to the acronym PAD for atherosclerotic
disease of the lower extremity arteries. Others have used the same
acronym to qualify atherosclerotic disease of the lower extremity
arteries and carotid arteries. In the current article and in line with the
European Society of Cardiology (ESC) guidelines, 4 we have stringently used the specific terms lower extremity arterial disease (LEAD)
and reserved PAD as the umbrella term encompassing all arterial diseases other than aorta and coronarie
An Asymmetric N-Rim Partially Substituted Calix[4]pyrrole: Its Affinity for Ag(I) and its Destruction by Hg(II)
No full textA new partially substituted calix[4] pyrrole derivative obtained by the introduction of three thioamide functionalities in the N-rim has been synthesised and fully characterised by 1H,13C, HSQC, ROESY NMR and mass spectroscopy. Computer modelling suggested an alternate conformation which was confirmed through ROESY 1H NMR. The receptor interacts only with the silver cation as shown by 1H NMR. The strength of interaction is quantitatively assessed by titration calorimetry. N-rim modification eliminates the possibility of interaction with anions. Unlike calix[4] pyrrole derivatives obtained by the introduction of functionalities through the meso-position, addition of Hg(NO3)2 leads to the degeneration of the receptor as demonstrated by 1H NMR, FTIR and XPS analyses. This is for the first time reported. Molecular simulation studies show significant strain in the mercury bound ligand in bonds, angles, torsions leading to the destruction of the receptor. Given the negative environmental impact produced by the availability of silver ions in aquatic organisms, the fundamental studies indicate that this receptor offers potential applications for monitoring silver (ion selective electrode) or indeed as a decontaminating material for removing silver ions from water
Los pájaros are feliz and are dreaming about gwiazdy: facilitating translingual creative writing in the primary classroom
No full textAlthough one in five state-educated children in England speaks
a language other than English at home, there is little space in the
National Curriculum for the expression of this linguistic heritage. In
this article, we make the case for facilitating multilingualism in the
primary classroom through translingual creative writing, which
involves mixing two or more languages. We draw on empirical
research with a class of lower Key Stage 2 children of diverse
linguistic backgrounds and abilities at a school in south London.
The pupils were set the task of writing a poem that combined
English with other languages so that we could observe how they
engaged with the process of translanguaging. We suggest that
translingual writing exercises in the classroom provide a range of
benefits, including the creation of a space for the valorisation of
children’s cultural capital; the facilitation of valuable peer-teaching
and collaboration; freedom to explore playfulness with language;
and a chance to experiment with and reflect on creative writing
processes
Holographic-Based mmW-Wideband Bidirectional Frequency Scanning Leaky Wave Antenna
No full textUtilizing the holography theory, a bidirectional
wideband leaky wave antenna in the millimetre wave (mmW)
band is presented. The antenna includes a printed pattern of continuous metallic strips on an Alumina 99:5% sheet, and a surface wave launcher (SWL) to produce the initial reference waves on the substrate. To achieve a bidirectional radiation pattern, the fundamental TE mode is excited by applying a Vivaldi antenna (as the SWL). The proposed holographic-based leaky wave antenna (HLWA) is fabricated and tested and the measured results are aligned with the simulated ones. The antenna has 22:6% fractional bandwidth with respect to the central frequency of 30 GHz. The interference pattern is designed to generate a 15 deg backward tilted bidirectional radiation
pattern with respect to the normal of the hologram sheet. The frequency scanning property of the designed HLWA is also investigated
Channel Measurement and Analysis for Polarimetric Wideband Outdoor Scenarios at 26 GHz: Directional vs Omni-Directional
No full textThis paper presents the measurement results and
analysis for outdoor wireless propagation channels at 26 GHz
over 2 GHz bandwidth for two receiver antenna polarization
modes. The angular and wideband properties of directional
and virtually omni-directional channels, such as angular spread,
root-mean-square delay spread and coherence bandwidth, are
analyzed. The results indicate that the reflections can have a significant
contribution in some realistic scenarios and increase the
angular and delay spreads, and reduce the coherence bandwidth
of the channel. The analysis in this paper also show that using
a directional transmission can result in an almost frequencyflat
fading channel over the measured 2 GHz bandwidth; which
consequently has a major impact on the choice of system design
choices such as beamforming and transmission numerology
Study on the Location of mmWave Antenna for the Autonomous Car’s Detection and Ranging Sensors
No full textThe effect of vehicle’s proximity on the radiation
pattern when the RADAR’s antenna is mounted on the body of autonomous cars is analysed. Two directional radiation patterns with different specifications are placed at different locations of a realistic car body model. The simulation is performed based on
ray-tracing method at 77 GHz, the standard frequency for self-driving applications. It is shown that to obtain a robust RADAR sensor, the antenna radiation pattern is better to have relatively higher gain and lower side-lobe-level (SLL), than narrower halfpower-
beamwidth (HPBW) and higher front-to-back (F/B) ratio.
Both academia and industry can benefit from this study
Characterization of particles emitted by pizzerias burning wood and briquettes: a case study at Sao Paulo, Brazil
No full textThe burning of biomass in pizza ovens can be an important source of air pollution. Fine particulate matter represents one of the most aggressive pollutants to human health, besides the potential to interfere with global radiative balance. A study in real-world condition was performed in three pizzerias in São Paulo city. Two of the pizzerias used eucalyptus timber logs and one used wooden briquettes. The results from the three pizzerias revealed high average concentrations of PM2.5: 6171.2 μg/m3 at the exit of the chimney and 68.2 μg/m3 in indoor areas. The burning of briquette revealed lower concentrations of PM2.5. BC represented approximately 20% and 30% of the PM2.5 mass concentration in indoor and at chimney exhaust, respectively. Among the trace elements, potassium, chlorine and sulphur were the most prevalent in terms of concentration. Scanning electron microscopy (SEM) analysis revealed particles with an individual and spherical morphology, i.e. the conglomeration of spherical particles, flattened particles in the formation of fibres, the overlapping of layers and the clustering of particles with sponge-like qualities. The average emission factors for PM2.5 and BC due to the burning of logs were 0.38 g/kg and 0.23 g/kg, respectively. The total emissions of PM2.5 and BC were 116.73 t/year and 70.65 t/year, respectively, in the burning of timber logs
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