Analysis of anti-multipath performance based on traditional acquisition algorithm of boc signal

At present, multipath interference is still an inevitable natural influencing factor for high-precision navigation and positioning. The signal transmitted by the satellite is reflected and refracted by the interference of the surrounding environment, which will cause certain error interference to the phase and pseudorange of the direct wave signal. In order to analyze the degree of interference caused by multipath errors in the signal acquisition process, and compare the anti-multipath performance advantages of the acquisition algorithm. In this paper, starting from the formation principle of multipath signals. Based on the analysis of the code loop phase detector technology of incoherent lead minus lag (EML), the MATLAB simulation analysis platform is built, and then The comparison and simulation experiment of multipath error of sine BOC modulation signal and cosine BOC modulation signal is carried out for two traditional acquisition algorithms which are ASPeCT acquisition algorithm and SCPC acquisition algorithm. The simulation results show that the anti-multipath performance of the ASPeCT acquisition algorithm is better than that of the SCPC algorithm

EMS decoding algorithm that introduced shuffled strategy and improved variable node update

Non-binary LDPC codes have excellent performance, but the decoding algorithm is complex. EMS algorithm reduces the search space of the check equation by truncating the iterative message vector, and exchanges performance for lower complexity. In this paper, we propose an EMS decoding algorithm (Shuffled_VNU_EMS) with a shuffled strategy and improved variable node update. This algorithm updates by column, so that the latest variable node information of the last column can be used. At the same time, to reduce the information oscillation, a weighting factor ß is introduced when updating the variable node information,ß= 0.9. The simulation results show that when the code length is 512, the code rate is 0.5 and the bit error rate is 10-4, the coding gain of the shuffled VNU EMS algorithm proposed in this paper is 0.18 dB higher than that of the classical EMS algorithm

Modeling and correction analysis of regional ionospheric modeling

The Global Navigation Satellite System (GNSS), due to its all-weather lobal monitoring and high precision, makes it possible to use GNSS observation data to accurately extract the total electron content (TEC) of the ionosphere and to study ionospheric activities. At the same time, the delay error caused by the ionosphere to GNSS signals is also one of the main sources of error in GNSS positioning. For regional users, using as few stations as possible to establish an ionospheric TEC model within the region has higher efficiency and range practicability. This paper realizes the establishment of a regional ionospheric TEC model based on spherical harmonics, and establishes an ionospheric TEC model in the 15∼45°N and 105°∼135°E regions, which is compatible with IGS (International GNSS Service, IGS) and CAS (Chinese Academy of Sciences, CAS), the overall difference is more than 70% within ±3TECU

Photometric Variability in the CSTAR Field: Results From the 2008 Data Set

The Chinese Small Telescope ARray (CSTAR) is the first telescope facility built at Dome A, Antarctica. During the 2008 observing season, the installation provided long-baseline and high-cadence photometric observations in the i-band for 18,145 targets within 20 deg2 CSTAR field around the South Celestial Pole for the purpose of monitoring the astronomical observing quality of Dome A and detecting various types of photometric variability. Using sensitive and robust detection methods, we discover 274 potential variables from this data set, 83 of which are new discoveries. We characterize most of them, providing the periods, amplitudes and classes of variability. The catalog of all these variables is presented along with the discussion of their statistical properties.Comment: 38 pages, 11 figures, 4 tables; Accepted for publication in ApJ

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Landslide Displacement Prediction Based on Time Series Analysis and Double-BiLSTM Model

In recent years, machine learning models facilitated notable performance improvement in landslide displacement prediction. However, most existing prediction models which ignore landslide data at each time can provide a different value and meaning. To analyze and predict landslide displacement better, we propose a dynamic landslide displacement prediction model based on time series analysis and a double-bidirectional long short term memory (Double-BiLSTM) model. First, the cumulative landslide displacement is decomposed into trend and periodic displacement components according to time series analysis via the exponentially weighted moving average (EWMA) method. We consider that trend displacement is mainly influenced by landslide factors, and we apply a BiLSTM model to predict landslide trend displacement. This paper analyzes the internal relationship between rainfall, reservoir level and landslide periodic displacement. We adopt the maximum information coefficient (MIC) method to calculate the correlation between influencing factors and periodic displacement. We employ the BiLSTM model for periodic displacement prediction. Finally, the model is validated against data pertaining to the Baishuihe landslide in the Three Gorges, China. The experimental results and evaluation indicators demonstrate that this method achieves a better prediction performance than the classical prediction methods, and landslide displacement can be effectively predicted