An Arctic-Tibetan Connection on Subseasonal to Seasonal Time Scale

Recent research indicates the great potentials of springtime land surface temperature (LST) as a new source of predictability to improve the subseasonal to seasonal climate prediction. In this study, we explore the initial cause of the springtime large-scale LST in Tibetan Plateau (TP) and disentangle its close connection with the February wave activities from the Arctic region. Our Maximum Covariance Analysis show that the spring LST in TP is significantly coupled with the regional snow cover in the preceding months. The latter is further strongly coupled with the February atmospheric circulation and wave activities in mid-to-high latitudes. When the atmospheric circulation is in a combined pattern of Arctic Oscillation and West Pacific teleconnection pattern, wave trains from the Arctic can propagate and reach the TP through northern and southern pathways. This brings dynamical and moisture conditions for the TP snowfall and builds a bridge for Arctic-Tibetan connection

Exact Outage Performance Analysis of Multiuser Multi-relay Spectrum Sharing Cognitive Networks

In this paper, we investigate the outage performance of dual-hop multiuser multi-relay cognitive radio networks under spectrum sharing constraints. Using an efficient relay-destination selection scheme, the exact and asymptotic closed-form expressions for the outage probability are derived. From these expressions it is indicated that the achieved diversity order is only determined by the number of secondary user (SU) relays and destinations, and equals to M+N (where M and N are the number of destination nodes and relay nodes, respectively). Further, we find that the coding gain of the SU network will be affected by the interference threshold $bar I$ at the primary user (PU) receiver. Specifically, as the increases of the interference threshold, the coding gain of the considered network approaches to that of the multiuser multi-relay system in the non-cognitive network. Finally, our study is corroborated by representative numerical examples

Green's function method for single-particle resonant states in relativistic mean field theory

Relativistic mean field theory is formulated with the Green's function method in coordinate space to investigate the single-particle bound states and resonant states on the same footing. Taking the density of states for free particle as a reference, the energies and widths of single-particle resonant states are extracted from the density of states without any ambiguity. As an example, the energies and widths for single-neutron resonant states in $^{120}$Sn are compared with those obtained by the scattering phase-shift method, the analytic continuation in the coupling constant approach, the real stabilization method and the complex scaling method. Excellent agreements are found for the energies and widths of single-neutron resonant states.Comment: 20 pages, 7 figure

Using LIP to Gloss Over Faces in Single-Stage Face Detection Networks

This work shows that it is possible to fool/attack recent state-of-the-art face detectors which are based on the single-stage networks. Successfully attacking face detectors could be a serious malware vulnerability when deploying a smart surveillance system utilizing face detectors. We show that existing adversarial perturbation methods are not effective to perform such an attack, especially when there are multiple faces in the input image. This is because the adversarial perturbation specifically generated for one face may disrupt the adversarial perturbation for another face. In this paper, we call this problem the Instance Perturbation Interference (IPI) problem. This IPI problem is addressed by studying the relationship between the deep neural network receptive field and the adversarial perturbation. As such, we propose the Localized Instance Perturbation (LIP) that uses adversarial perturbation constrained to the Effective Receptive Field (ERF) of a target to perform the attack. Experiment results show the LIP method massively outperforms existing adversarial perturbation generation methods -- often by a factor of 2 to 10.Comment: to appear ECCV 2018 (accepted version

Flux rope proxies and fan-spine structures in active region NOAA 11897

Employing the high-resolution observations from the Solar Dynamics Observatory (SDO) and the Interface Region Imaging Spectrograph (IRIS), we statistically investigate flux rope proxies in NOAA AR 11897 from 14-Nov-2013 to 19-Nov-2013 and display two fan-spine structures in this AR. For the first time, we detect flux rope proxies of NOAA 11897 for total 30 times in 4 different locations. These flux rope proxies were either tracked in both lower and higher temperature wavelengths or only detected in hot channels. Specially, none of these flux rope proxies was observed to erupt, but just faded away gradually. In addition to these flux rope proxies, we firstly detect a secondary fan-spine structure. It was covered by dome-shaped magnetic fields which belong to a larger fan-spine topology. These new observations imply that considerable amounts of flux ropes can exist in an AR and the complexity of AR magnetic configuration is far beyond our imagination.Comment: 8 pages, 8 figures, Accepted for publication in A&

A Sensitive and Reliable Carbon Monoxide Monitor for Safety-Focused Applications in Coal Mine Using a 2.33-μ\mu m Laser Diode

In this paper, a stable and reliable carbon monoxide (CO) monitoring system with high sensitivity (at sub-ppm level) was designed and demonstrated with particular reference to use in the mining industry, tailoring the design specifically for forecasting spontaneous combustion, a major hazard to miners. An appropriate strong CO absorption line was used to minimize the interferences expected from gases present in ambient air, with several preferred CO absorption lines selected and investigated, therefore choosing a distributed feedback (DFB) laser operating at a wavelength of 2330.18 nm as the excitation source. Through a detailed investigation, a minimum detection limit of ~0.2 ppm and a measurement precision of <50 ppb were achieved with a 1 s averaging time. Further in tests, a long-term continuous monitoring evaluation was carried out, demonstrated the excellent stability and reliability of the developed CO monitor. The results obtained have validated the potential of this design of a CO monitoring system for practical monitoring applications underground to enhance safety in the mining industry