Flag-transitive automorphism groups of 22-designs with λ≥(r,λ)2\lambda\geq (r,\lambda)^2 are not product type

In this paper we show that a flag-transitive automorphism group $G$ of a non-trivial $2$-$(v,k,\lambda)$ design with $\lambda\geq (r, \lambda)^2$ is not of product action type. In conclusion, $G$ is a primitive group of affine or almost simple type.Comment: 13 pages,2 figure

Research on Impulse Radio Ultra - wideband Positioning Method Based on Combined BP Neural Network and SVM

Intelligent tour guide is a comprehensive service based on tourist\u27s location, which is closely related to Geographic Information System (GIS), mobile positioning technology and Location-Based Service (LBS). But the intelligent tour guide field urgently needs the integrated positioning and navigation technology inside and outside the room. IR-UWB technology is suitable for positioning, tracking, navigation and communication in complex indoor environment, and is considered as the most potential indoor positioning technology to realize seamless connection between indoor and outdoor with outdoor positioning technologies such as GPS. However, one of the main problems facing IR-UWB positioning is Non-Line-Of-Sight (NLOS) error. Based on the advantages of BP neural network and support vector machine, this paper proposes a multi-model fusion algorithm to mitigate the NLOS propagation error of the time difference of arrival (TDOA) and the angle of arrival (AOA) of IR-UWB signal, and then uses TDOA/AOA hybrid positioning that mitigates the NLOS error. Simulation results show that the combined algorithm has stronger NLOS resistance and higher positioning accuracy than the single machine learning algorithm in mitigation NLOS errors

Digital Infrastructure: Overcoming the digital divide in China and the European Union. CEPS Research Report, November 2017

This study is the result of collaboration among a group of researchers from CEPS and Zhejiang University (ZJU), who decided to team up and analyse the experience of China and the EU in bridging the digital divide. While acknowledging that both China and Europe have undertaken major efforts to reduce socio-economic and geographical disparities by providing network access to ever more citizens, the authors found that investing in physical access alone is not sufficient to enhance inclusion in the information society. They argue that public authorities should also adopt corollary policies to spur social and economic cohesion through innovations that enable disadvantaged regions to catch up with more developed urban areas. In this context, the report calls upon governments to promote digital innovation and entrepreneurship, foster coordinated efforts and adapt their educational systems to the changing labour market

Digital Infrastructure: Overcoming the digital divide in emerging economies. CEPS Special Report, 5 April 2017

Since the 1990s when the internet began to be commercialised globally, the debate on how to close the digital divide has attracted widespread attention. In this Policy Brief, we review the literature on the digital divide in emerging economies with a view to explaining: 1) how internet connectivity promotes social and economic inclusiveness, efficiency and innovation; 2) why the physical access to the internet alone is insufficient to capture the full benefits of digital technology and what other social conditions should be considered; and 3) how to further connect the unconnected population. The digital divide prevents societies from harnessing the full benefits that information and communication technologies can deliver. In this context, actions to foster physical access to the internet remain essential, but they are not sufficient to ensure a truly inclusive information society. Therefore, strong leadership is needed at the global and local levels, to ensure more coordinated efforts among governments, local authorities and actors on the ground. Conversely, maintaining the status quo, while technology progressively pervades every sector of the economy, may critically widen disparities across countries and within national territories. This report offers two sets of policy recommendations: 1) a set of general principles that the G20 should endorse to overcome disparities between emerging and advanced economies; and 2) a set of policy guidelines each nation should follow to bridge the digital divide and foster inclusiveness

Generative Modeling in Structural-Hankel Domain for Color Image Inpainting

In recent years, some researchers focused on using a single image to obtain a large number of samples through multi-scale features. This study intends to a brand-new idea that requires only ten or even fewer samples to construct the low-rank structural-Hankel matrices-assisted score-based generative model (SHGM) for color image inpainting task. During the prior learning process, a certain amount of internal-middle patches are firstly extracted from several images and then the structural-Hankel matrices are constructed from these patches. To better apply the score-based generative model to learn the internal statistical distribution within patches, the large-scale Hankel matrices are finally folded into the higher dimensional tensors for prior learning. During the iterative inpainting process, SHGM views the inpainting problem as a conditional generation procedure in low-rank environment. As a result, the intermediate restored image is acquired by alternatively performing the stochastic differential equation solver, alternating direction method of multipliers, and data consistency steps. Experimental results demonstrated the remarkable performance and diversity of SHGM.Comment: 11 pages, 10 figure

Astragaloside IV Ameliorates Airway Inflammation in an Established Murine Model of Asthma by Inhibiting the mTORC1 Signaling Pathway

Astragaloside IV (AS-IV), a main active constituent of Astragalus membranaceus, has been confirmed to have antiasthmatic effects. However, it remained unclear whether the beneficial effects of AS-IV on asthma were attributed to the mTOR inhibition; this issue was the focus of the present work. BALB/c mice were sensitized and challenged with ovalbumin followed with 3 weeks of rest/recovery and then reexposure to ovalbumin. AS-IV was administrated during the time of rest and reexposure. The characteristic features of allergic asthma, including airway hyperreactivity, histopathology, cytokines (IL-4, IL-5, IL-13, IL-17, and INF-γ), and CD4+CD25+Foxp3+Treg cells in bronchoalveolar lavage fluid (BALF), and downstream proteins of mTORC1/2 signaling were examined. AS-IV markedly suppressed airway hyperresponsiveness and reduced IL-4, IL-5, and IL-17 levels and increased INF-γ levels in the BALF. Histological studies showed that AS-IV markedly decreased inflammatory infiltration in the lung tissues. Notably, AS-IV inhibited mTORC1 activity, whereas it had limited effects on mTORC2, as assessed by phosphorylation of mTORC1 and mTORC2 substrates S6 ribosomal protein, p70 S6 Kinase, and Akt, respectively. CD4+CD25+Foxp3+Treg cells in BALF were not significantly changed by AS-IV. Together, these results suggest that the antiasthmatic effects of AS-IV were at least partially from inhibiting the mTORC1 signaling pathway

Improved heat transfer for pyroelectric energy harvesting applications using a thermal conductive network of aluminum nitride in PMN–PMS–PZT ceramics

The harvesting of waste heat is attracting increasing attention, due to its abundance and potential benefits to the environment. However, the need for high heat transfer rates in thermal harvesting systems is a longstanding obstacle for their practical application. In this work, we construct thermally conductive networks in Pb[(MnxNb1−x)1/2(MnxSb1−x)1/2]y(Zr95Ti5)1−yO3 (lead magnesium niobate–lead antimony–manganese–lead zirconate titanate: PMN–PMS–PZT) ceramics to improve heat transfer and enhance their ferroelectric properties by use of a thermally conductive AlN additive dispersed in the ceramic matrix. The ferroelectric properties, pyroelectric coefficient and thermal conductivity of the PMN–PMS–PZT: AlN composite materials are influenced by the AlN content as a result of the formation of random bridges or thermally conductive networks for phonon transfer in the ceramic matrix, thereby leading to high heat transfer. For a PMN–PMS–PZT composite with a 0.2 wt% AlN content, the ferroelectric properties, pyroelectric coefficient and thermal conductivity are shown to be enhanced owing to the improved crystallinity and density, and the relative permittivity is also reduced, which results in optimized pyroelectric figure of merits. This combination of materials property enhancements is shown to be beneficial for high performance pyroelectric materials in devices for energy harvesting applications

Sustainability in the Age of Platforms. CEPS Special Report. June 2019

Over the past few decades, new digital platforms such as China’s Alibaba, Japan’s Rakuten and the U.S.’s eBay have grown from startups into multinational giants. With a few clicks of the keyboard, these online marketplaces bring together a seller and a buyer from anywhere in the globe. This study examines the transformative impact of online marketplaces on economic, social and environmental sustainability. It finds great opportunities. Platforms promote growth, break down barriers of distance and leap over rigid class structures, bringing marginalized outsiders into the mainstream. The study also identifies dangers stemming from the growth of e-commerce, from the reduction of labor protection to an explosion of shipping waste. What are the responsibilities of platforms? How can they promote sustainability? Policymakers are asking these questions, but struggling to find the correct balance between the opportunities against the dangers. Until now, these questions have received little attention from scholars. This study fills a much-needed void by providing some initial answers and recommendations for improvement