Based on SDSS g, r and SCUSS (South Galactic Cap of u-band Sky Survey) \(u\) photometry, we develop a photometric calibration for estimating the stellar metallicity from \(u-g\) and \(g-r\) colors by ...using the SDSS spectra of 32,542 F- and G-type main sequence stars, which cover almost \(3700\) deg\(^{2}\) in the south Galactic cap. The rms scatter of the photometric metallicity residuals relative to spectrum-based metallicity is \(0.14\) dex when \(g-r<0.4\), and \(0.16\) dex when \(g-r>0.4\). Due to the deeper and more accurate magnitude of SCUSS \(u\) band, the estimate can be used up to the faint magnitude of \(g=21\). This application range of photometric metallicity calibration is wide enough so that it can be used to study metallicity distribution of distant stars. In this study, we select the Sagittarius (Sgr) stream and its neighboring field halo stars in south Galactic cap to study their metallicity distribution. We find that the Sgr stream at the cylindrical Galactocentric coordinate of \(R\sim 19\) kpc, \(\left| z\right| \sim 14\) kpc exhibits a relative rich metallicity distribution, and the neighboring field halo stars in our studied fields can be modeled by two-Gaussian model, with peaks respectively at Fe/H\(=-1.9\) and Fe/H\(=-1.5\).
An ultra-low-power-consumption high-gain low-noise amplifier for wireless applications operating in the 2.45 GHz industrial-scientific-medical (ISM) band has been developed. Under low dc power bias ...of 1.0 V and 0.96 mA, the amplifier demonstrated the state-of-the-art performance with a gain of 30.1 dB, NF of 4.31 dB, input and output return loss of less than -14 dB and the corresponding -1 dB compression point of -19.47 dBm at 2.45 GHz, achieving a gain/P/sub dc/ figure of merit of 31.35 dB/mW and a gain/NF.P/sub dc/ ratio of 7.27/mW, which are the highest ever reported at S-band.
Embedded with advanced sensors, cameras, and processors, the emerging automated driving vehicles are capable of sensing the environment and conducting automobile operation, paving the way to modern ...intelligent transportation systems with high safety and efficiency. On the other hand, vehicular communication networks (VCNs) connect vehicles, infrastructures, clouds, and all other devices with communication modules, whereby vehicles can obtain local and global information to make intelligent operation decisions. Although sensing-based automated driving technologies and VCNs have been investigated independently, their interactions and mutual benefits are still underdeveloped. In this article, we argue that VCNs have attractive potential to enhance onboard sensing-based automated vehicles from different perspectives, such as driving safety, transportation efficiency, as well as customer experience. A case study is conducted to demonstrate that traffic jams can be relieved at intersections with automated driving vehicles coordinated with each other through VCNs. Furthermore, we highlight critical and interesting issues for future research, based on the specific requirements posed by automated driving in VCNs.
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