With the maturity of SOC, IC designers not only consider IP (Intellectual Property) level issues such as performance, the area andpower dissipation, but also system-level issues such as bus on-chi, which has an effect on system performance, power dissipation, chip area and system upgrade. This paper proposes an improved AHB bus frame adapted to a high-performance Network Security Accelerator (NSA), which processes giga bits per second for the bulk cipher, as well as 3000 times per second for the RSA key-exchanges of 1024 bits, 1200 times scalar multiplications of 256 bits for general curve over GF(p), and 1500 times for those over GF(2 n ). In this paper, dual one-way 64-bit buses are proposed. The improved bus frame settles issues of data congestion, the bus handover and the iterant transfer for the same data. 25.6Gbps data transfer rate is attainable with 200 MHz clock frequency. The basic transfer mode of the improved bus is burst transfer which reaches upto 64 beats. This busframe meets the need of high speed transfer for high-performance NSA. Meanwhile, eliding address bus in the improved bus frame makes the issues of power consumption, the chip area and the complexity ofroutingfor large system alleviative.
Data of low‐energy (<28 keV) H + and O + ions obtained by the FAST satellite were used to investigate the statistical properties of multiple ion band structures (MIBS) that are characterized by multiple O + /H + components with discrete energies. MIBS distributions for H + and O + ions had different relationships with the AL index, invariant latitude (ILAT), and magnetic local time, suggesting different formation mechanisms. O + MIBSs were observed during magnetically active periods around the equatorward boundary of the auroral oval mainly in the dusk and midnight sectors, while H + MIBSs were observed during quiet times at higher latitudes in the dawn and dusk sectors. O + MIBSs shifted toward lower latitudes with decreasing AL index due to the expansion of the auroral oval during magnetically active periods. Both maximum and minimum energies of O + MIBSs decrease with decreasing ILAT, which is consistent with velocity filter effects caused by convective transport from high to low latitudes in the nightside. The statistical properties obtained from the FAST observations suggest that O + MIBSs supply O + ions from the ionosphere to the inner magnetosphere during magnetic storms and contribute to the storm time ring current development.
A compact dual-band filtering antenna is proposed for WLAN(2.4G/5.2G) Application. It is a integrated design of a step impedance resonators dual-band bandpass filter and a patch antenna using aperture coupled feed techniques. The patch antenna can be viewed as a radiator but also the last resonator of the dual-band bandpass filter. Compared with traditional wireless communication system, the filtering antenna leaves out the 50 Ω transmission line instead of an aperture coupled structure, thus, no more additional space is needed, which makes the size more compact. Besides, the proposed filtering antenna provides a high band-edge gain selectivity.
The global vegetation cover is increasing and is expected continue increasing till 2100, owing to CO2 fertilisation and afforestation. This greening phenomenon may create conflicting demands for water between ecosystems, atmosphere, and humans, and has aroused a series of controversies. For exploring the effects of greening phenomenon on terrestrial water availability, we estimated the balance between water supply (precipitation and snowmelt runoff) and water consumption (evaporation, human water use, transpiration, and interception losses) in the global vegetation land based on the outputs of 30 models from the Coupled Model Intercomparison Project Phase 6. Water consumption showed an increasing trend in most regions of global vegetation land for the period 1982–2016 as well as 2040–2100, mainly driven by the increased transpiration and interception losses for vegetation growth (contributing 85.4–90.5%). Although the greening phenomenon widely exacerbates water shortages, 94.3–98.8% of the global vegetation land was still found to be sustainable during 1982–2100, due to the water supply exceeding the total water consumption. More attention should be paid to the unsustainable regions where the total water consumption exceeded the total water supply. Such areas were continuously found to increase from 2.1–5.3% (1982–2016) to 5.4–5.7% (2040–2100) of the global vegetation land. We predict that Oceania, Northern India, the southern coastal regions of North America will be transformed from sustainable regions in 1982–2016 to unsustainable regions in 2040–2100.
As polluted water bodies are often small in area and widely distributed, performing artificial field screening is difficult; however, remote-sensing-based screening has the advantages of being rapid, large-scale, and dynamic. Polluted water bodies often show anomalous water colours, such as black, grey, and red. Therefore, the large-scale recognition of suspected polluted water bodies through high-resolution remote-sensing images and water colour can improve the screening efficiency and narrow the screening scope. However, few studies have been conducted on such kinds of water bodies. The hue angle of a water body is a parameter used to describe colour in the International Commission on Illumination (CIE) colour space. Based on the measured data, the water body with a hue angle greater than 230.958° is defined as a water colour anomaly, which is recognised based on the Sentinel-2 image through the threshold set in this study. The results showed that the hue angle of the water body was extracted from the Sentinel-2 image, and the accuracy of the hue angle calculated by the in situ remote-sensing reflectance Rrs (λ) was evaluated, where the root mean square error (RMSE) and mean relative error (MRE) were 4.397° and 1.744%, respectively, proving that this method is feasible. The hue angle was calculated for a water colour anomaly and a general water body in Qiqihar. The water body was regarded as a water colour anomaly when the hue angle was >230.958° and as a general water body when the hue angle was ≤230.958°. High-quality Sentinel-2 images of Qiqihar taken from May 2016 to August 2019 were chosen, and the position of the water body remained unchanged; there was no error or omission, and the hue angle of the water colour anomaly changed obviously, indicating that this method had good stability. Additionally, the method proposed is only suitable for optical deep water, not for optical shallow water. When this method was applied to Xiong’an New Area, the results showed good recognition accuracy, demonstrating good universality of this method. In this study, taking Qiqihar as an example, a surface survey experiment was conducted from October 14 to 15, 2018, and the measured data of six general and four anomalous water sample points were obtained, including water quality terms such as Rrs (λ), transparency, water colour, water temperature, and turbidity.
As an application-driven network, wireless sensor network generally requires high data reliability to maintain detection and response capabilities. Although two approaches, which are retransmission and redundancy, have been proposed to enhance data reliability, the theoretical work is required to evaluate their impact on transmission reliability and energy efficiency. In this paper, we offer a comprehensive theoretical study on the packet arrival probability and average energy consumption for both approaches. Our analysis indicates that when loss probability remains low or moderate, erasure coding, a scheme based on redundancy, is more reliable and energy efficient than retransmission. However, the performance of erasure coding would largely deteriorate under high packet loss condition. We also demonstrate that its resistance capability against packet loss weakens as hop number increases. Furthermore, with the increase in redundancy, erasure coding has to sacrifice the advantage of energy efficiency for reliability.
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