Cascaded multiplier-free implementation of adaptive anti-jamming filter based on GNSS receiver

Evaluating the computational complexity is critical for assessing the time-domain anti-jamming performance of GNSS receivers. The multiplier is the core component that contributes to the computational complexity in time-domain anti-jamming. However, current algorithms aimed at reducing the complexity of time-domain anti-jamming typically concentrate on shortening the filter length, which fails to address the high computational complexity introduced by the use of multipliers. This paper introduces a cascaded multiplier-free approach for implementing time-domain anti-jamming in navigation receivers. We propose a numerical power decomposition technique based on optimal Canonical Signed Digit coding and coefficient decomposition. By substituting the multiplier with minimal adder and shift operations, the computational complexity of the anti-jamming filter with a high quantization bit-width can be considerably decreased. An optimization strategy is presented, and the low-complexity multiplier-free technique is applied to the time-domain anti-jamming filter. Compared to the traditional Canonical Signed Digit multiplier-free technique, our method can reduce the components required for a 12-bit quantization anti-interference filter by one adder, 20 shift operations, and five coded word lengths, while maintaining a pseudo-range measurement deviation below 0.27 ns

Physiological Effects of Superoxide Dismutase on Altered Visual Function of Retinal Ganglion Cells in db/db Mice

Background: The C57BLKS/J db/db (db/db) mouse is a widely used type 2 diabetic animal model, and this model develops early inner retinal neuronal dysfunction beginning at 24 weeks. The neural mechanisms that mediate early stage retinal dysfunction in this model are unknown. We evaluated visual response properties of retinal ganglion cells (RGCs) during the early stage of diabetic insult (8, 12, and 20 wk) in db/db mice and determined if increased oxidative stress plays a role in impaired visual functions of RGCs in 20 wk old db/db mice. Methodology/Principal Findings: In vitro extracellular single-unit recordings from RGCs in wholemount retinas were performed. The receptive field size, luminance threshold, and contrast gain of the RGCs were investigated. Although ONand OFF-RGCs showed a different time course of RF size reduction, by 20 wk, the RF of ON- and OFF-RGCs were similarly affected. The LT of ON-RGCs was significantly elevated in 12 and 20 wk db/db mice compared to the LT of OFF-RGCs. The diabetic injury also affected contrast gains of ON- and OFF-RGCs differently. The generation of reactive oxidative species (ROS) in fresh retina was estimated by dihydroethidium. Superoxide dismutase (SOD) (300 unit/ml) was applied in Ames medium to the retina, and visual responses of RGCs were recorded for five hours. ROS generation in the retinas of db/db mice increased at 8wk and continued to progress at 20 wk of ages. In vitro application of SOD improved visual functions in 20 wk db/db mice but the SOD treatment affected ON- and OFF-RGCs differently in db/m retina

Synergizing Fe2O3 nanoparticles on single atom Fe-N-C to achieve NO3RR to NH3 at industrial partial current densities

Nitrate reduction reaction in an electrochemical system has recently supplied us with a new pathway to generate ammonia for a post-carbon world. However, the low current density and yield rate as shown in relevant studies limit the NO3RR process. In this thesis, we developed a new catalyst system consisting of γ-Fe2O3 nanoparticles supported on atomically dispersed Fe-N-C. By combining the activity of both the nanoparticles and single atom sites, we were able to achieve an ultrahigh NO3RR activity, with a maximum partial current density of 1.95 A/cm2, a Faradaic efficiency for NH3 of 100%, and an NH3 yield rate of over 9 mmol hr-1 cm-2. Our result of XPS after electrochemical experiments demonstrates the importance of a pre-reduction activation step to generate exposed Fe0 sites from the γ-Fe2O3 (Fe3+) and durability study reveals the robustness of the catalyst, maintaining a current of -1.4 A cm-2, a near unity FENH3 over 24 hours at highly reductive potentials. These findings highlight the potential of active particle-active support systems to enhance NO3RR performance and achieve industrially relevant current densities

A Novel CPW-Fed UWB Antenna with Band-Stop Function

A novel coplanar waveguide-fed (CPW) ultrawideband (UWB) antenna with band-stop function is presented in this paper. The proposed antenna comprises a CPW-fed slot rectangular patch with an open stub ground plane, and two inverted L-shaped strip conductors are fabricated on the back plane. The overall size of the antenna is 25 × 25 × 1.6 mm2, and it achieves good impedance matching and radiation gain. Simulated and measured results show that the designed antenna operates at 2.9 GHz–13.08 GHz with band rejection in the frequency band of 7.7 GHz–9.05 GHz for satellite applications, and the proposed antenna is suitable for UWB wireless communication applications

NLOS Signal Detection Based on Single Orthogonal Dual-Polarized GNSS Antenna

Nowadays users have a high demand for the accuracy of position and velocity, but errors caused by non-line-of-sight (NLOS) signals cannot be removed effectively. Since the GNSS signal is right-hand circular polarized (RHCP), the axial ratio of the strong NLOS signal is larger than that of the Line-of-Sight (LOS) signal. Based on the difference of the axial ratio, a method for NLOS signal detection using single orthogonal dual-polarized antenna is proposed. The antenna has two channels to receive two orthogonal linear polarized components of the incoming signals. Parallel cross-cancellation is used to remove the LOS signal while maintaining most of the NLOS signals from the receiving signals. The residual NLOS signals are then detected by conventional GNSS digital processor in real time without any prior knowledge of their characteristics. The proposed method makes use of the polarization and spatial information and can detect long delay NLOS signal by miniature and inexpensive receiver GNSS. The effectiveness of the proposed method is confirmed by simulation data

Optimal Order of Time-Domain Adaptive Filter for Anti-Jamming Navigation Receiver

Adaptive filtering algorithms can be used on the time-domain processing of navigation receivers to suppress interference and maintain the navigation and positioning function. The filter length can affect the interference suppression performance and hardware utilization simultaneously. In practical engineering, the filter length is usually set to a large number to guarantee anti-jamming performance, which means a high-performance receiver requires a high-complexity anti-jamming filter. The study aims at solving the problem by presenting a design method for the optimal filter order in the time-domain anti-jamming receiver, with no need for detailed interference information. According to interference bandwidth and jam-to-signal ratio (JSR), the approach designed a band-stop filter by Kaiser window for calculating the optimal filter order to meet interference suppression requirements. The experimental results show that the time-domain filtering processing has achieved good interference suppression performance for engineering requirements with optimal filter order in satellite navigation receivers

Luteolin inhibits behavioral sensitization by blocking methamphetamine-induced MAPK pathway activation in the caudate putamen in mice.

GOAL: To investigate the effect of luteolin on methamphetamine (MA)-induced behavioral sensitization and mitogen-activated protein kinase (MAPK) signal transduction pathway activation in mice. METHODS: Mice received a single dose of MA to induce hyperactivity or repeated intermittent intraperitoneal injections of MA to establish an MA-induced behavioral sensitization mouse model. The effect of luteolin on the development and expression of MA-induced hyperactivity and behavioral sensitization was examined. The expression and activity of ΔFosB and the levels of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2), phosphorylated c-Jun N-terminal kinase (pJNK), and phosphorylated p38 mitogen-activated protein kinase (pp38) in the caudate putamen (CPu) were measured by western blot. RESULTS: Luteolin significantly decreased hyperactivity as well as the development and expression of MA-induced behavioral sensitization in mice. ΔFosB, pERK1/2, and pJNK levels in the CPu were higher in MA-treated mice than in control mice, whereas the pp38 level did not change. Injection of luteolin inhibited the MA-induced increase in ΔFosB, pERK1/2, and pJNK levels, but did not affect the pp38 level. CONCLUSIONS: Luteolin inhibits MA-induced hyperactivity and behavioral sensitization in mice through the ERK1/2/ΔFosB pathway. Furthermore, the JNK signaling pathway might be involved in MA-induced neurodegeneration in the CPu, and luteolin inhibits this process