Improved Reduced Latency Soft-Cancellation Algorithm for Polar Decoding

Soft-cancellation(SCAN) is a soft output iterative algorithm widely used in polar decoding. This algorithm has better decoding performance than reduced latency soft-cancellation(RLSC) algorithm, which can effectively reduce the decoding delay of SCAN algorithm by 50% but has obvious performance loss. A modified reduced latency soft-cancellation(MRLSC) algorithm is presented in the paper. Compared with RLSC algorithm, LLR information storage required in MRLSC algorithm can be reduced by about 50%, and better decoding performance can be achieved with only a small increase in decoding delay. The simulation results show that MRLSC algorithm can achieve a maximum block error rate(BLER) performance gain of about 0.4 dB compared with RLSC algorithm when code length is 2048. At the same time, compared with the performance of several other algorithms under(1024, 512) polar codes, the results show that the throughput of proposed MRLSC algorithm has the advantage at the low and medium signal-to-noise ratio(SNR) and better BLER performance at the high SNR.

Evaluation of Arctic Sea Ice Drift and its Relationship with Near-surface Wind and Ocean Current in Nine CMIP6 Models from China

The simulated Arctic sea ice drift and its relationship with the near-surface wind and surface ocean current during 1979-2014 in nine models from China that participated in the sixth phase of the Coupled Model Intercomparison Project(CMIP6)are examined by comparison with observational and reanalysis datasets.Most of the models reasonably represent the Beaufort Gyre(BG)and Transpolar Drift Stream(TDS)in the spatial patterns of their long-term mean sea ice drift,while the detailed location,extent,and strength of the BG and TDS vary among the models.About two-thirds of the models agree with the observation/reanalysis in the sense that the sea ice drift pattern is consistent with the near-surface wind pattern.About the same proportion of models shows that the sea ice drift pattern is consistent with the surface ocean current pattern.In the observation/reanalysis,however,the sea ice drift pattern does not match well with the surface ocean current pattern.All nine models missed the observational widespread sea ice drift speed acceleration across the Arctic.For the Arctic basin-wide spatial average,five of the nine models overestimate the Arctic long-term(1979-2014)mean sea ice drift speed in all months.Only FGOALS-g3 captures a significant sea ice drift speed increase from 1979 to 2014 both in spring and autumn.The increases are weaker than those in the observation.This evaluation helps assess the performance of the Arctic sea ice drift simulations in these CMIP6 models from China.

Response of Tomato Sugar and Acid Metabolism and Fruit Quality under Different High Temperature and Relative Humidity Conditions

The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture.However,there is little information about the precise interaction between them on tomato fruit quality.The objectives of this study were to explore the effects of the combined stress of high temperature and relative humidity on the sugar and acid metabolism and fruit quality of tomato fruits,and to determine the best relative air humidity for fruit quality under high temperature environments.Four temperature treatments(32℃,35℃,38℃,41℃),three relative air humidity(50%,70%,90%)and four duration(3,6,9,12 d)orthogonal experiments were conducted,with 28℃,50%as control.The results showed that under high temperature and relative air humidity,the activity of sucrose metabolizing enzymes in young tomato fruits changed,which reduced fruits soluble sugar content;in addition,enzyme activities involved phosphopyruvate carboxylase(PEPC),mitochondria aconitase(MDH)and citrate synthetase(CS)increased which increased the content of organic acids(especially malic acid).Eventually,vitamin C,total sugar and sugar-acid ratio decreased significantly,while the titratable acid increased,resulting in a decrease in fruit flavor quality and nutritional quality in ripe fruit.Specifically,a temperature of 32℃and a relative air humidity of 70%were the best cultivation conditions for tomato reproductive growth period under high temperature.Our results indicating that fruit quality reduced under high temperature at the flowering stage,while increasing the relative air humidity to 70%could alleviate this negative effect.Our results are benefit to better understand the interaction between microclimate parameters under specific climatic conditions in the greenhouse environment and their impact on tomato flavor quality.

Code-Based Preservation Mechanism of Electronic Record in Electronic Record Center of Cloud Storage

With the rapid development of E-commerce and E-government,there are so many electronic records have been produced.The increasing number of electronic records brings about storage difficulties,the traditional electronic records center is difficult to cope with the current fast growth requirements of electronic records storage and management.Therefore,it is imperative to use cloud storage technology to build electronic record centers.However,electronic records also have weaknesses in the cloud storage environment,and one of them is that once electronic record owners or managers lose physical control of them,the electronic records are more likely to be tampered with and destroyed.So,the paper builds a reliable electronic records preservation system based on coding theory.It can effectively guarantee the reliability of record storage when the electronic record is damaged,and the original electronic record can be restored by redundant coding,thus ensuring the reliable storage of electronic records.

Data Security Defense and Algorithm for Edge Computing Based on Mean Field Game

With the development of the Internet of Things,the edge devices are increasing.Cyber security issues in edge computing have also emerged and caused great concern.We propose a defense strategy based on Mean field game to solve the security issues of edge user data during edge computing.Firstly,an individual cost function is formulated to build an edge user data security defense model.Secondly,we research the𝜀𝜀-Nash equilibrium of the individual cost function with finite players and prove the existence of the optimal defense strategy.Finally,by analyzing the stability of edge user data loss,it proves that the proposed defense strategy is effective.

Modes of Mesoscale Convective System Organization During Meiyu Season over the Yangtze River Basin

Mesoscale convective systems(MCSs) are classified and investigated through a statistical analysis of composite radar reflectivity data and station observations during June and July 2010-2012.The number of linear-mode MCSs is slightly larger than the number of nonlinear-mode MCSs.Eight types of linear-mode MCSs are identified:trailing stratiform MCSs(TS),leading stratiform MCSs(LS),training line/adjoining stratiform MCSs(TL/AS),back-building/quasi-stationary MCSs(BB),parallel stratiform MCSs(PS),broken line MCSs(BL),embedded line MCSs(EL),and long line MCSs(LL).Six of these types have been identified in previous studies,but EL and LL MCSs are described for the first time by this study.TS,LS,PS,and BL MCSs are all moving systems,while TL/AS,BB,EL,and LL MCSs are quasi-stationary.The average duration of linear-mode MCSs is more than 7 h.TL/AS and TS MCSs typically have the longest durations.Linear-mode MCSs often develop close to the Yangtze River,especially over low-lying areas and river valleys.The diurnal cycle of MCS initiation over the Yangtze River valley contains multiple peaks.The vertical distribution of environmental wind is decomposed into storm-relative perpendicular and parallel wind components.The environmental wind field is a key factor in determining the organizational mode of a linear-mode MCS.

Assessing remotely sensed and reanalysis products in characterizing surface soil moisture in the Mongolian Plateau

Soil moisture(SM)plays a crucial role in the dynamics of coupled atmosphere,water,energy,and carbon cycles.In this study,the spatiotemporal distribution and variations of SM in the Mongolian Plateau were investigated for the period of 1982-2018 based on four gridded SM datasets.Taking the observed SM from 33 monitoring stations as a reference,the reliability of these four gridded products was validated,and the three-cornered hat(TCH)method was also applied to evaluate their uncertainties.Major results indicated that all these four products underestimated the SM in this region at different levels.The ERA-Interim SM performed much better than other three products,with a higher R of 0.53 and lower ubRMSE of 0.0378 m^(3)·m^(−3).Except for ECV,the surface SM exhibited a decreasing trend at−0.0004 to−0.0008 m^(3)·m^(−3)/decade in the warm season(from April to October)over the past 37 years.The greatest decreases in SM occurred in the summer season.Precipitation change plays a more important role in explaining the variations of SM than temperature reported by partial correlation analysis.The results of this study will benefit our understanding of the climate change effects and the protection of the ecological systems in this region.

Avalanche mechanism analysis of 4H-SiC n-i-p and p-i-n avalanche photodiodes working in Geiger mode

Understanding detailed avalanche mechanisms is critical for design optimization of avalanche photodiodes(APDs).In this work,avalanche characteristics and single photon counting performance of 4H-SiC n-i-p and p-i-n APDs are compared.By studying the evolution of breakdown voltage as a function of incident light wavelength,it is confirmed that at the deep ultraviolet(UV)wavelength region the avalanche events in 4H-SiC n-i-p APDs are mainly induced by hole-initiated ionization,while electron-initiated ionization is the main cause of avalanche breakdown in 4H-SiC p-i-n APDs.Meanwhile,at the same dark count rate,the single photon counting efficiency of n-i-p APDs is considerably higher than that of p-i-n APDs.The higher performance of n-i-p APDs can be explained by the larger impact ionization coefficient of holes in 4H-SiC.In addition,this is the first time,to the best of our knowledge,to report single photon detection performance of vertical 4H-SiC n-i-p-n APDs.

Simulation of the Northern and Southern Hemisphere Annular Modes by CAMS-CSM

As leading modes of the planetary-scale atmospheric circulation in the extratropics, the Northern Hemisphere(NH)annular mode(NAM) and Southern Hemisphere(SH) annular mode(SAM) are important components of global circulation, and their variabilities substantially impact the climate in mid-high latitudes. A 35-yr(1979-2013) simulation by the climate system model developed at the Chinese Academy of Meteorological Sciences(CAMS-CSM) was carried out based on observed sea surface temperature and sea ice data. The ability of CAMS-CSM in simulating horizontal and vertical structures of the NAM and SAM, relation of the NAM to the East Asian climate, and temporal variability of the SAM is examined and validated against the observational data. The results show that CAMS-CSM captures the zonally symmetric and out-of-phase variations of sea level pressure anomaly between the midlatitudes and polar zones in the extratropics of the NH and SH. The model has also captured the equivalent barotropic structure in tropospheric geopotential height and the meridional shifts of the NH and SH jet systems associated with the NAM and SAM anomalies. Furthermore, the model is able to reflect the variability of northern and southern Ferrel cells corresponding to the NAM and SAM anomalies. The model reproduces the observed relationship of the boreal winter NAM with the East Asian trough and air temperature over East Asia. It also captures the upward trend of the austral summer SAM index during recent decades. However, compared with the observation, the model shows biases in both the intensity and center locations of the NAM's and SAM's horizontal and vertical structures. Specifically, it overestimates their intensities.