Positioning Accuracy Improvement via Distributed Location Estimate in Cooperative Vehicular Networks

The development of cooperative vehicle safety (CVS) applications, such as collision warnings, turning assistants, and speed advisories, etc., has received great attention in the past few years. Accurate vehicular localization is essential to enable these applications. In this study, motivated by the proliferation of the Global Positioning System (GPS) devices, and the increasing sophistication of wireless communication technologies in vehicular networks, we propose a distributed location estimate algorithm to improve the positioning accuracy via cooperative inter-vehicle distance measurement. In particular, we compute the inter-vehicle distance based on raw GPS pseudorange measurements, instead of depending on traditional radio-based ranging techniques, which usually either suffer from high hardware cost or have inadequate positioning accuracy. In addition, we improve the estimation of the vehicles' locations only based on the inaccurate GPS fixes, without using any anchors with known exact locations. The algorithm is decentralized, which enhances its practicability in highly dynamic vehicular networks. We have developed a simulation model to evaluate the performance of the proposed algorithm, and the results demonstrate that the algorithm can significantly improve the positioning accuracy.Comment: To appear in Proc. of the 15th International IEEE Conference on Intelligent Transportation Systems (IEEE ITSC'12

Indoor radio channel of bluetooth technology

This thesis discusses the findings of the final year project involving the characterisation of indoor radio channel specified by Bluetooth technology through theoretical analysis, simulations and actual measurements through field experiments. The concepts of indoor radio propagation effects and its statistical models arc explored. In addition, Bluetooth specifications are also studied and presented in Section 1. These provided a clear understanding of the radio propagation behaviour inside a building and the radio performance of Bluetooth specifications. Profound understanding of the propagation characteristics of the indoor radio channel is a major requirement for successful design of any indoor wireless communication systems. The knowledge is used here to investigate Bluetooth radio performance. Detailed characterisation of indoor radio channel is studied and presented in section 2. Path loss model and amplitude fading model are used in the theoretical analysis, simulations and field experiments have been done to characterise the indoor channel. Field experiments and its measurements were performed and recorded to verify against the simulated results. Attenuation factor of various materials were measured since it is a critical component effecting the path loss calculation. These are presented in section 3

Asymmetric influence of emotion in the sharing of COVID-19 science on social media : observational study

Background: Unlike past pandemics, COVID-19 is different to the extent that there is an unprecedented surge in both peer-reviewed and preprint research publications, and important scientific conversations about it are rampant on online social network, even among lay people. Clearly, this new phenomenon of scientific discourse is not well understood in that we do not know the diffusion patterns of peer-reviewed publications vis-à-vis preprints and what makes them viral. Objective: To inform health science communicator and policy makers’ decision on how to promote reliable sharing of crucial pandemic science on social media, this paper aims to examine how the emotionality of the messages about preprint and peer-reviewed publications shape their diffusion through online social networks. Methods: We collected a large sample of all Twitter discussion of early month COVID-19 medical research outputs in both preprint servers and peer-reviewed journals and conducted statistical analyses to examine how the emotional valence, specific emotion, as well as scientists’ participation influence the retweet rate. Results: Our large-scale analyses (n=243,567) revealed that scientific publications with positive emotion tweets were transmitted faster than those with negative emotion tweets, especially for messages about preprints. Our results also showed that scientists’ participation on social media could accentuate the positive emotion effects on the sharing of peer-reviewed publications. Conclusions: Clear communication of critical science is crucial in the nascent stage of a pandemic. Through revealing the emotional dynamics in the social media sharing of COVID-19 scientific outputs, our study offers scientists and policy makers an avenue to shape the discussion and diffusion of emerging scientific publications by manipulating the emotionality of the tweets

Asymmetric spin-wave dispersion due to Dzyaloshinskii-Moriya interaction in an ultrathin Pt/CoFeB film

Employing Brillouin spectroscopy, strong interfacial Dzyaloshinskii-Moriya interactions have been observed in an ultrathin Pt/CoFeB film. Our micromagnetic simulations show that spin-wave nonreciprocity due to asymmetric surface pinning is insignificant for the 0.8nmthick CoFeB film studied. The observed high asymmetry of the monotonic spin wave dispersion relation is thus ascribed to strong Dzyaloshinskii-Moriya interactions present at the Pt/CoFeB interface. Our findings should further enhance the significance of CoFeB as an important material for magnonic, spintronic and skyrmionic applications.Comment: 12 pages, 4 figure

Reconstruction of lattice parameters and beam momentum distribution from turn-by-turn beam position monitor readings in circular accelerators

In high chromaticity circular accelerators, rapid decoherence of the betatron motion of a particle beam can make the measurement of lattice and bunch values, such as Courant-Snyder parameters and betatron amplitude, difficult. A method for reconstructing the momentum distribution of a beam from beam position measurements is presented. Further analysis of the same beam position monitor data allows estimates to be made of the Courant-Snyder parameters and the amplitude of coherent betatron oscillation of the beam. The methods are tested through application to data taken on the linear nonscaling fixed field alternating gradient accelerator, EMMA

Better inpatient health quality at lower cost: Should I participate in the online healthcare community first?

As policy makers across the globe look to health information technology (HIT) as a means of improving the efficiency of the healthcare systems, it has sparked significant interest in understanding how HIT might help achieve that. While researchers have e

Preliminary assessment of Polytrichum commune extract as an antimicrobial soap ingredient

Mosses have long been used in traditional Chinese medicine due to the presence of secondary metabolites which have shown high biological activities. In particular, these secondary metabolites have demonstrated effective antibacterial activity against pathogenic microorganisms. In this study, the influence of different extraction solvents on the antibacterial activities of the Polytrichum commune was carried out using the disc diffusion method. Results showed that both 12.5 mg/mL of methanol moss extract and 6.25 mg/mL of ethanol moss extract were the most effective concentrations against Bacillus cereus and Pseudomonas aeruginosa. Additionally, the P. commune extracts were included as an added ingredient in soap bases to produce antibacterial soap prototypes where the effectiveness of the soaps containing the extracts in removing microorganisms from actual test individuals was carried out. Results of the thumb impression test of test individuals showed that the growth of microbial reduced after washing hands with the usage of both liquid and solid soap with the addition of P. commune extracts. Moreover, the antibacterial soaps performed better in eliminating microorganisms in comparison to control soaps without P. commune extracts. Taken together, P. commune extract could be a good candidate as a value-added ingredient utilized to produce antibacterial soaps due to its antibacterial properties