The study on designs for the baseline parameterization has aroused attention in recent years. This paper focuses on two-level regular designs for the baseline parameterization. A general result on the relationship bet...The study on designs for the baseline parameterization has aroused attention in recent years. This paper focuses on two-level regular designs for the baseline parameterization. A general result on the relationship between K-aberration and word length pattern is developed.展开更多
When the cycle slips take place in the attitude determination of a moving platform, the precision of the attitude will be impaired badly. A method of cycle slip detection and correction is proposed, which is suitable ...When the cycle slips take place in the attitude determination of a moving platform, the precision of the attitude will be impaired badly. A method of cycle slip detection and correction is proposed, which is suitable to the dynamic measurement using GPS carrier phase: the cycle slips detection is first achieved by triple difference observables, then the cycle slips correction is performed with baseline length constraint. The simulation results show that the proposed method is effective to the dynamic cycle slips problem.展开更多
Urban topsoil is the most frequent interface between human society and natural environment.The accumulation of heavy metals in the urban topsoil has a direct effect on residents'life and health.The geochemical bas...Urban topsoil is the most frequent interface between human society and natural environment.The accumulation of heavy metals in the urban topsoil has a direct effect on residents'life and health.The geochemical baseline of heavy metals is an objective description of the general level of heavy metals in the urban topsoil.Meanwhile,the determination of geochemical baseline is necessary for regional environmental management,especially in coal cities prone to heavy metal pollution.Heavy metal pollution has become an environmental problem in Fuxin City,China for a long time.To establish the geochemical baseline of heavy metals in the topsoil of Fuxin City and to evaluate the ecological risk of the topsoil,we collected 75 topsoil samples(0–20 cm)and analyzed the concentrations of Cu,Ni,Zn,Pb,Cr,Cd,Hg and As through X-ray fluorescence spectrometry,atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry.We determined the geochemical baseline of heavy metals in the topsoil of Fuxin City by using iteration removal,box-whisker plot,cumulative frequency curve and reference metal normalization;evaluated the contamination risk and ecological risk of the topsoil by using the baseline factor index,Nemerow index and Hakanson potential ecological risk index;and identified the source category of heavy metals in the topsoil by using a pedigree clustering heatmap.Results showed that the geochemical baseline values were 42.86,89.34,92.23,60.55,145.21,0.09,0.08 and 4.17 mg/kg for Cu,Ni,Zn,Pb,Cr,Cd,Hg and As,respectively.The results of Nemerow index and Hakanson potential ecological risk index indicated that the urban topsoil in the study area was slightly contaminated and suffering low potential ecological risk.The main contaminated areas dominated in the middle part and northeast part of the study area,especially in the western Haizhou Strip Mine.The result of baseline factor index indicated that Hg and Cd were the major pollution elements.Using a pedigree clustering heatmap,we divided the sources of these heavy metals into three types:type I for Ni and Cr,largely represented the enrichment of heavy metals from natural sources;type II for Cu,Pb,Zn,Cd and As,mainly represented the enrichment of heavy metals from anthropogenic sources;and type III for Hg,represented the form of both natural and anthropogenic inputs.展开更多
Baseline offset in digital strong-motion acceleration record and initial velocity can produce unrealistic results for ground velocity and displacement derived from the acceleration by integration. A new method is prop...Baseline offset in digital strong-motion acceleration record and initial velocity can produce unrealistic results for ground velocity and displacement derived from the acceleration by integration. A new method is proposed for the baseline correction and initial velocity calculation. It is based on linear least-squares fitting of the pre-event portion of velocity derived from the uncorrected acceleration data. Compared with the conventional method,which is based on removing the mean values of the pre-event portions of the acceleration and velocity traces,this method has clearer physical meaning and better stability.展开更多
The precision of Earth's gravitational field from GRACE up to degree and order 120 was studied for different inter-satellite ranges using the improved energy conservation principle. Our simulated result shows that: ...The precision of Earth's gravitational field from GRACE up to degree and order 120 was studied for different inter-satellite ranges using the improved energy conservation principle. Our simulated result shows that: For long wavelength (L≤20) at degree 20, the cumulative geoid-height error gradually decreased with increasing range, from 0. 052 cm for 110 km to 1. 156 times and 1. 209 times as large for 220 km and 330 kin, respectively. For medium-wavelength ( 100 ≤ L ≤ 120) at degree 120, the cumulative geoid-height error de- creased from 13. 052 cm for 110 km, to 1. 327 times and 1. 970 times as large for the ranges of 220 km and 330 km, respectively; By adopting an optimal range of 220 ± 50 km, we can suppress considerably the loss of precision in the measurement of the Earth' s long-wavelength and medium-wavelength gravitational field.展开更多
Inter-satellite link(ISL)scheduling is required by the BeiDou Navigation Satellite System(BDS)to guarantee the system ranging and communication performance.In the BDS,a great number of ISL scheduling instances must be...Inter-satellite link(ISL)scheduling is required by the BeiDou Navigation Satellite System(BDS)to guarantee the system ranging and communication performance.In the BDS,a great number of ISL scheduling instances must be addressed every day,which will certainly spend a lot of time via normal metaheuristics and hardly meet the quick-response requirements that often occur in real-world applications.To address the dual requirements of normal and quick-response ISL schedulings,a data-driven heuristic assisted memetic algorithm(DHMA)is proposed in this paper,which includes a high-performance memetic algorithm(MA)and a data-driven heuristic.In normal situations,the high-performance MA that hybridizes parallelism,competition,and evolution strategies is performed for high-quality ISL scheduling solutions over time.When in quick-response situations,the data-driven heuristic is performed to quickly schedule high-probability ISLs according to a prediction model,which is trained from the high-quality MA solutions.The main idea of the DHMA is to address normal and quick-response schedulings separately,while high-quality normal scheduling data are trained for quick-response use.In addition,this paper also presents an easy-to-understand ISL scheduling model and its NP-completeness.A seven-day experimental study with 10080 one-minute ISL scheduling instances shows the efficient performance of the DHMA in addressing the ISL scheduling in normal(in 84 hours)and quick-response(in 0.62 hour)situations,which can well meet the dual scheduling requirements in real-world BDS applications.展开更多
Bone is an endocrine organ involved in modulating glucose homeostasis. The role of the bone formation marker osteocalcin (OCN) in predicting diabetes was reported, but with conflicting results. No study has explored...Bone is an endocrine organ involved in modulating glucose homeostasis. The role of the bone formation marker osteocalcin (OCN) in predicting diabetes was reported, but with conflicting results. No study has explored the association between baseline bone resorption activity and incident diabetes or prediabetes during follow-up. Our objective was to examine the relationship between the baseline bone resorption marker crosslinked C-telopeptide of type I collagen (CTX) and glycemic dysregulation after 4 years. This longitudinal study was conducted in a university teaching hospital. A total of 195 normal glucose tolerant (NGT) women at baseline were invited for follow-up. The incidence of diabetes and prediabetes (collectively defined as dysglycemia) was recorded. A total of 128 individuals completed the 4-year study. The overall conversion rate from NGT to dysglycemia was 31.3%. The incidence of dysglycemia was lowest in the middle tertile [16.3% (95% confidence interval (CI), 6.8%-30.70/0)] compared with the lower [31.0% (95% CI, 17.2%-46.1%)] and upper [46.5% (95% CI, 31.2%-62.6%)] tertiles of CTX, with a significant difference seen between the middle and upper tertiles (P = 0.002 5). After adjusting for multiple confounding variables, the upper tertile of baseline CTX was associated with an increased risk of incident dysglycemia, with an odds ratio of 7.09 (95% CI, 1.73-28.99) when the middle tertile was the reference. Osteoclasts actively regulate glucose homeostasis in a biphasic model that moderately enhanced bone resorption marker CTX at baseline provides protective effects against the deterioration of glucose metabolism, whereas an overactive osteoclastic function contributes to an increased risk of subsequent dysglycemia.展开更多
To establish an efficient inter-satellite link (ISL) in an LEO network, the effect of geometric characteristics of ISL on the ISLs and the devices on the LEO satellite should be examined. Because of the continuous mov...To establish an efficient inter-satellite link (ISL) in an LEO network, the effect of geometric characteristics of ISL on the ISLs and the devices on the LEO satellite should be examined. Because of the continuous movement of the LEO satellite, the time-varying behaviours of the ISL's geometric charactersistics continuously change with the changes of the satellite's position on the orbit. These dynamic geometric characteristics of the ISLs are important for ISL's performance analyzing and the design of the devices on the LEO satellite. This paper describes dynamic geometric characteristics of ISL, analyzes the impact of these regulations on the tracking system of the satellite's antenna and the power adjusting system of the satellite's transmitter, with the Iridium system as an example.展开更多
This study was aimed to evaluate the agreement between the self-reported sodium intake level and 24-h urine sodium excretion level in Chinese. The 24-h urine collection was conducted among 2112 adults aged 18-69 years...This study was aimed to evaluate the agreement between the self-reported sodium intake level and 24-h urine sodium excretion level in Chinese. The 24-h urine collection was conducted among 2112 adults aged 18-69 years randomly selected in Shandong Province, China. The subjects were asked whether their sodium intake was low, moderate, or high. The weighted kappa statistics was calculated to assess the agreement between 24-h urine sodium excretion level and self-reported sodium intake level. One third of the subjects reported low sodium intake level. About 70% of the subjects had mean 24-h sodium excretion 〉9 g/d, but reported low or moderate sodium intake.展开更多
The penalized least squares(PLS)method with appropriate weights has proved to be a successful baseline estimation method for various spectral analyses.It can extract the baseline from the spectrum while retaining the ...The penalized least squares(PLS)method with appropriate weights has proved to be a successful baseline estimation method for various spectral analyses.It can extract the baseline from the spectrum while retaining the signal peaks in the presence of random noise.The algorithm is implemented by iterating over the weights of the data points.In this study,we propose a new approach for assigning weights based on the Bayesian rule.The proposed method provides a self-consistent weighting formula and performs well,particularly for baselines with different curvature components.This method was applied to analyze Schottky spectra obtained in 86Kr projectile fragmentation measurements in the experimental Cooler Storage Ring(CSRe)at Lanzhou.It provides an accurate and reliable storage lifetime with a smaller error bar than existing PLS methods.It is also a universal baseline-subtraction algorithm that can be used for spectrum-related experiments,such as precision nuclear mass and lifetime measurements in storage rings.展开更多
The beam windows of high-energy beam lines are important,and it is sometimes difficult to design because it is necessary to ensure particle propagation with minimum disturbance and fulfill mechanical requirements at t...The beam windows of high-energy beam lines are important,and it is sometimes difficult to design because it is necessary to ensure particle propagation with minimum disturbance and fulfill mechanical requirements at the same time.The upstream decay pipe window of the long baseline neutrino facility at Fermilab has an extremely large diameter(1.8 m),with a thickness of only 1.5 mm to separate the helium atmosphere in the decay pipe and the nitrogen atmosphere on the other side.Furthermore,the center of this dish-shaped window is expected to be a200-mm-diameter beryllium dish welded to the outside aluminum alloy A6061,and this welded combination must withstand extreme conditions of a 2.4-MW,high-energy proton beam without leakage.These severe conditions make the design of this window an unprecedented challenge.This paper describes the static thermal-structural analyses based on which the structure has been optimized,as well as dynamic analyses for understanding the shockwave effects originating in the beam.After optimization,the maximum von Mises stresses in the window decreased significantly in both normal operation and accident cases,making our design very reasonable.展开更多
文摘The study on designs for the baseline parameterization has aroused attention in recent years. This paper focuses on two-level regular designs for the baseline parameterization. A general result on the relationship between K-aberration and word length pattern is developed.
文摘When the cycle slips take place in the attitude determination of a moving platform, the precision of the attitude will be impaired badly. A method of cycle slip detection and correction is proposed, which is suitable to the dynamic measurement using GPS carrier phase: the cycle slips detection is first achieved by triple difference observables, then the cycle slips correction is performed with baseline length constraint. The simulation results show that the proposed method is effective to the dynamic cycle slips problem.
基金the National Natural Science Foundation of China(41271064)the Foundation of Liaoning Educational Committee,China(L201783640)the PhD Research Startup Foundation of Liaoning University,China(BS2018L014)。
文摘Urban topsoil is the most frequent interface between human society and natural environment.The accumulation of heavy metals in the urban topsoil has a direct effect on residents'life and health.The geochemical baseline of heavy metals is an objective description of the general level of heavy metals in the urban topsoil.Meanwhile,the determination of geochemical baseline is necessary for regional environmental management,especially in coal cities prone to heavy metal pollution.Heavy metal pollution has become an environmental problem in Fuxin City,China for a long time.To establish the geochemical baseline of heavy metals in the topsoil of Fuxin City and to evaluate the ecological risk of the topsoil,we collected 75 topsoil samples(0–20 cm)and analyzed the concentrations of Cu,Ni,Zn,Pb,Cr,Cd,Hg and As through X-ray fluorescence spectrometry,atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry.We determined the geochemical baseline of heavy metals in the topsoil of Fuxin City by using iteration removal,box-whisker plot,cumulative frequency curve and reference metal normalization;evaluated the contamination risk and ecological risk of the topsoil by using the baseline factor index,Nemerow index and Hakanson potential ecological risk index;and identified the source category of heavy metals in the topsoil by using a pedigree clustering heatmap.Results showed that the geochemical baseline values were 42.86,89.34,92.23,60.55,145.21,0.09,0.08 and 4.17 mg/kg for Cu,Ni,Zn,Pb,Cr,Cd,Hg and As,respectively.The results of Nemerow index and Hakanson potential ecological risk index indicated that the urban topsoil in the study area was slightly contaminated and suffering low potential ecological risk.The main contaminated areas dominated in the middle part and northeast part of the study area,especially in the western Haizhou Strip Mine.The result of baseline factor index indicated that Hg and Cd were the major pollution elements.Using a pedigree clustering heatmap,we divided the sources of these heavy metals into three types:type I for Ni and Cr,largely represented the enrichment of heavy metals from natural sources;type II for Cu,Pb,Zn,Cd and As,mainly represented the enrichment of heavy metals from anthropogenic sources;and type III for Hg,represented the form of both natural and anthropogenic inputs.
基金supported by the National Natural Science Foundation of China( 41004020)the Director Foundation of Institute of Seismology,CEA(IS200926044)
文摘Baseline offset in digital strong-motion acceleration record and initial velocity can produce unrealistic results for ground velocity and displacement derived from the acceleration by integration. A new method is proposed for the baseline correction and initial velocity calculation. It is based on linear least-squares fitting of the pre-event portion of velocity derived from the uncorrected acceleration data. Compared with the conventional method,which is based on removing the mean values of the pre-event portions of the acceleration and velocity traces,this method has clearer physical meaning and better stability.
基金supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences for Distinguished Young Scholar(KZCX2-EW-QN114)the National Natural Science Foundation of China(41004006,41131067,11173049)+5 种基金the Merit-based Scientific Research Foundation of the State Ministry of Human Resources and Social Security of China for Returned Overseas Chinese Scholars(2011)the Open Research Fund Program of the Key Laboratory of Geo-Informatics of State Bureau of Surveying and Mapping(201031)the Open Research Fund Program of the Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences(2011-04)the Frontier Field Program of Knowledge Innovation of Institute of Geodesy and Geophysics of Chinese Academy of Sciencesthe Open Fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(PLN1113)the Hubei Province Key Laboratory of Refractories and Ceramics Ministry-Province jointly-Constructed Cultivation Base for State key Laboratory(G201009)
文摘The precision of Earth's gravitational field from GRACE up to degree and order 120 was studied for different inter-satellite ranges using the improved energy conservation principle. Our simulated result shows that: For long wavelength (L≤20) at degree 20, the cumulative geoid-height error gradually decreased with increasing range, from 0. 052 cm for 110 km to 1. 156 times and 1. 209 times as large for 220 km and 330 kin, respectively. For medium-wavelength ( 100 ≤ L ≤ 120) at degree 120, the cumulative geoid-height error de- creased from 13. 052 cm for 110 km, to 1. 327 times and 1. 970 times as large for the ranges of 220 km and 330 km, respectively; By adopting an optimal range of 220 ± 50 km, we can suppress considerably the loss of precision in the measurement of the Earth' s long-wavelength and medium-wavelength gravitational field.
基金supported by the National Natural Science Foundation of China(61773120)the National Natural Science Fund for Distinguished Young Scholars of China(61525304)+2 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of China(2014-92)the Hunan Postgraduate Research Innovation Project(CX2018B022)the China Scholarship Council-Leiden University Scholarship。
文摘Inter-satellite link(ISL)scheduling is required by the BeiDou Navigation Satellite System(BDS)to guarantee the system ranging and communication performance.In the BDS,a great number of ISL scheduling instances must be addressed every day,which will certainly spend a lot of time via normal metaheuristics and hardly meet the quick-response requirements that often occur in real-world applications.To address the dual requirements of normal and quick-response ISL schedulings,a data-driven heuristic assisted memetic algorithm(DHMA)is proposed in this paper,which includes a high-performance memetic algorithm(MA)and a data-driven heuristic.In normal situations,the high-performance MA that hybridizes parallelism,competition,and evolution strategies is performed for high-quality ISL scheduling solutions over time.When in quick-response situations,the data-driven heuristic is performed to quickly schedule high-probability ISLs according to a prediction model,which is trained from the high-quality MA solutions.The main idea of the DHMA is to address normal and quick-response schedulings separately,while high-quality normal scheduling data are trained for quick-response use.In addition,this paper also presents an easy-to-understand ISL scheduling model and its NP-completeness.A seven-day experimental study with 10080 one-minute ISL scheduling instances shows the efficient performance of the DHMA in addressing the ISL scheduling in normal(in 84 hours)and quick-response(in 0.62 hour)situations,which can well meet the dual scheduling requirements in real-world BDS applications.
基金supported by projects from the National Natural Science Foundation of China(81370977,81570796 and 81370018)by the Shanghai Science and Technology Committee(14411960900)
文摘Bone is an endocrine organ involved in modulating glucose homeostasis. The role of the bone formation marker osteocalcin (OCN) in predicting diabetes was reported, but with conflicting results. No study has explored the association between baseline bone resorption activity and incident diabetes or prediabetes during follow-up. Our objective was to examine the relationship between the baseline bone resorption marker crosslinked C-telopeptide of type I collagen (CTX) and glycemic dysregulation after 4 years. This longitudinal study was conducted in a university teaching hospital. A total of 195 normal glucose tolerant (NGT) women at baseline were invited for follow-up. The incidence of diabetes and prediabetes (collectively defined as dysglycemia) was recorded. A total of 128 individuals completed the 4-year study. The overall conversion rate from NGT to dysglycemia was 31.3%. The incidence of dysglycemia was lowest in the middle tertile [16.3% (95% confidence interval (CI), 6.8%-30.70/0)] compared with the lower [31.0% (95% CI, 17.2%-46.1%)] and upper [46.5% (95% CI, 31.2%-62.6%)] tertiles of CTX, with a significant difference seen between the middle and upper tertiles (P = 0.002 5). After adjusting for multiple confounding variables, the upper tertile of baseline CTX was associated with an increased risk of incident dysglycemia, with an odds ratio of 7.09 (95% CI, 1.73-28.99) when the middle tertile was the reference. Osteoclasts actively regulate glucose homeostasis in a biphasic model that moderately enhanced bone resorption marker CTX at baseline provides protective effects against the deterioration of glucose metabolism, whereas an overactive osteoclastic function contributes to an increased risk of subsequent dysglycemia.
文摘To establish an efficient inter-satellite link (ISL) in an LEO network, the effect of geometric characteristics of ISL on the ISLs and the devices on the LEO satellite should be examined. Because of the continuous movement of the LEO satellite, the time-varying behaviours of the ISL's geometric charactersistics continuously change with the changes of the satellite's position on the orbit. These dynamic geometric characteristics of the ISLs are important for ISL's performance analyzing and the design of the devices on the LEO satellite. This paper describes dynamic geometric characteristics of ISL, analyzes the impact of these regulations on the tracking system of the satellite's antenna and the power adjusting system of the satellite's transmitter, with the Iridium system as an example.
基金supported by funds from the Chinese Center for Disease Control and Prevention(China CDC)the National Center for Chronic and Non-communicable Disease Control and Prevention,China CDCthe Technical Development Plan in Shandong(implemented by Shandong CDC,Grant number:2012GSF11828)
文摘This study was aimed to evaluate the agreement between the self-reported sodium intake level and 24-h urine sodium excretion level in Chinese. The 24-h urine collection was conducted among 2112 adults aged 18-69 years randomly selected in Shandong Province, China. The subjects were asked whether their sodium intake was low, moderate, or high. The weighted kappa statistics was calculated to assess the agreement between 24-h urine sodium excretion level and self-reported sodium intake level. One third of the subjects reported low sodium intake level. About 70% of the subjects had mean 24-h sodium excretion 〉9 g/d, but reported low or moderate sodium intake.
基金supported by the National Key R&D Program of China(No.2018YFA0404401)CAS Project for Young Scientists in Basic Research(No.YSBR-002)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB34000000).
文摘The penalized least squares(PLS)method with appropriate weights has proved to be a successful baseline estimation method for various spectral analyses.It can extract the baseline from the spectrum while retaining the signal peaks in the presence of random noise.The algorithm is implemented by iterating over the weights of the data points.In this study,we propose a new approach for assigning weights based on the Bayesian rule.The proposed method provides a self-consistent weighting formula and performs well,particularly for baselines with different curvature components.This method was applied to analyze Schottky spectra obtained in 86Kr projectile fragmentation measurements in the experimental Cooler Storage Ring(CSRe)at Lanzhou.It provides an accurate and reliable storage lifetime with a smaller error bar than existing PLS methods.It is also a universal baseline-subtraction algorithm that can be used for spectrum-related experiments,such as precision nuclear mass and lifetime measurements in storage rings.
基金supported by the National Key Research and Development Program of China(No.2017YFE0106100)。
文摘The beam windows of high-energy beam lines are important,and it is sometimes difficult to design because it is necessary to ensure particle propagation with minimum disturbance and fulfill mechanical requirements at the same time.The upstream decay pipe window of the long baseline neutrino facility at Fermilab has an extremely large diameter(1.8 m),with a thickness of only 1.5 mm to separate the helium atmosphere in the decay pipe and the nitrogen atmosphere on the other side.Furthermore,the center of this dish-shaped window is expected to be a200-mm-diameter beryllium dish welded to the outside aluminum alloy A6061,and this welded combination must withstand extreme conditions of a 2.4-MW,high-energy proton beam without leakage.These severe conditions make the design of this window an unprecedented challenge.This paper describes the static thermal-structural analyses based on which the structure has been optimized,as well as dynamic analyses for understanding the shockwave effects originating in the beam.After optimization,the maximum von Mises stresses in the window decreased significantly in both normal operation and accident cases,making our design very reasonable.