291 research outputs found

    Stable scalable control of soliton propagation in broadband nonlinear optical waveguides

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    We develop a method for achieving scalable transmission stabilization and switching of NN colliding soliton sequences in optical waveguides with broadband delayed Raman response and narrowband nonlinear gain-loss. We show that dynamics of soliton amplitudes in NN-sequence transmission is described by a generalized NN-dimensional predator-prey model. Stability and bifurcation analysis for the predator-prey model are used to obtain simple conditions on the physical parameters for robust transmission stabilization as well as on-off and off-on switching of MM out of NN soliton sequences. Numerical simulations for single-waveguide transmission with a system of NN coupled nonlinear Schr\"odinger equations with 2N42 \le N \le 4 show excellent agreement with the predator-prey model's predictions and stable propagation over significantly larger distances compared with other broadband nonlinear single-waveguide systems. Moreover, stable on-off and off-on switching of multiple soliton sequences and stable multiple transmission switching events are demonstrated by the simulations. We discuss the reasons for the robustness and scalability of transmission stabilization and switching in waveguides with broadband delayed Raman response and narrowband nonlinear gain-loss, and explain their advantages compared with other broadband nonlinear waveguides.Comment: 37 pages, 7 figures, Eur. Phys. J. D (accepted

    Video Quality Assessment: From 2D to 3D - Challenges and Future Trends

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    International audienceThree-dimensional (3D) video is gaining a strong momentum both in the cinema and broadcasting industries as it is seen as a technology that will extensively enhance the user's visual experience. One of the major concerns for the wide adoption of such technology is the ability to provide sufficient visual quality, especially if 3D video is to be transmitted over a limited bandwidth for home viewing (i.e. 3DTV). Means to measure perceptual video quality in an accurate and practical way is therefore of highest importance for content providers, service providers, and display manufacturers. This paper discusses recent advances in video quality assessment and the challenges foreseen for 3D video. Both subjective and objective aspects are examined. An outline of ongoing efforts in standards-related bodies is also provided

    Evaluation of genetic diversity of Vietnamese dogs based on mitochondrial DNA hypervariable-1 region

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    Haplogroup E were detected with high frequency in the population of Phu Quoc ridgeback dogs suggesting that this Vietnamese valuable dog breed originated from domestic dogs harbouring haplogroup E from Vietnam’s mainland or from East Asia where the presence of haplogroup E was reported. Evaluation of the genetic diversity of the Vietnam’s mainland dogs and haplogroup Escreening would support us in tracking out the origin of Phu Quoc ridgeback dog

    A preliminary study of photometric redshifts based on the Wide Field Survey Telescope

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    The Wide Field Survey Telescope (WFST) is a dedicated time-domain multi-band (uu, gg, rr, ii, and zz) photometric survey facility under construction. In this paper, we present a preliminary study that assesses the quality of photometric redshifts based on WFST by utilizing mock observations derived with the galaxy catalog in the COSMOS/UltraVISTA field. We apply the template fitting technique to estimate photometric redshifts by using the ZEBRA photometric-redshift code and adopting a modified set of adaptive templates. We evaluate the bias (median relative offset between the output photometric redshifts and input redshifts), normalized median absolute deviation (σNMAD\sigma_{\rm NMAD}) and outlier fraction (foutlierf_{\rm outlier}) of photometric redshifts in two typical WFST observational cases, the single 30-second exposure observations (hereafter shallow mode) and co-added 50-minute exposure observations (hereafter deep mode). We find bias\la0.006, \sigma_{\rm NMAD}\la0.03, and f_{\rm outlier}\la5\% in the shallow mode and bias0.005\approx 0.005, σNMAD0.06\sigma_{\rm NMAD}\approx 0.06, and foutlier17%f_{\rm outlier}\approx 17\%--27%27\% in the deep mode, respectively, under various lunar phases. Combining the WFST mock observational data with that from the upcoming CSST and Euclid surveys, we demonstrate that the zphotz_{\rm phot} results can be significantly improved, with foutlier1%f_{\rm outlier}\approx 1\% and σNMAD0.02\sigma_{\rm NMAD}\approx 0.02.Comment: 20 pages, 13 figures. Accepted for publication in Research in Astronomy and Astrophysics (RAA

    An Empirical Research on Customers’ Awareness of E-Commerce in the Context of Vietnamese Developing Economies

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    Many research studies have been conducted in the field of e-commerce, which can contribute for academic background and development of e-commerce around the world. In Vietnam, the awareness of customers toward e-commerce is limited for the emerging of this industry in Vietnam recently. This study tries to figure out research model explains the factors and to study the awareness of customers that influence the behaviors and acceptance of users buying online in the developing economy. According to the research, buying online is quite risky. Therefore, product safety would be the purchasing decision's priority. Online sales providers need to provide a safe way of ensuring consumers ' purchasing process. Through hard qualification process, they need to shortlist the good quality product. The sale would grow dramatically as consumers gained confidence. Not only should they care about the short-term profit in order to get the products of low quality
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