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Surveillance of childhood blood lead levels in 11 cities of China

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World Journal of Pediatrics 2014年第1期10卷 29-37页

作者： Tao Li Yao-Hua Dai Xiao-Hua Xie Zang-Wen Tan Shuai-Ming Zhang Zong-Han Zhu department of Integrated early childhood Development Capital Institute of Pediatrics BeijingChina Chinese Pediatrician Association BeijingChina

Background:Exposure to lead can be deleterious to children’s *** for blood lead levels(BLLs)is reported every year in the USA and some other ***,such reports are lacking in China which has the world’s largest population of *** this study,we provided the latest nationally representative data on BLLs among Chinese children living in cities,described the change in BLLs since 2004,and explored the risk factors for elevated BLLs(EBLLs)among ***:We studied 12693 children aged 0–6 years in 2004 and 11255 children aged 0–6 years in *** evaluated the average BLLs and the prevalence of EBLLs,and a multivariate logistic regression model was used to estimate predictors of ***:The geometric mean BLLs of children aged 0–6 years dropped by 16%(from 46.38±2.10μg/L in 2004 to 38.95±1.83μg/L in 2010),while the prevalence of EBLLs dropped by 87%(from 9.78%in 2004 to 1.32%in 2010).In a multivariate analysis,the following factors were associated with EBLLs:(1)children being cared for at home or at a boarding nursery(compared to children being cared for in a day nursery),(2)children having fathers with a lower education level,and(3)children often eating popcorn and chewing fingernails or sucking fingers were associated with ***:The results of this study demonstrated a substantial decline in BLLs from 2004 to 2010 among Chinese children 0–6 years living in ***,these levels were higher than levels in countries,such as the USA,Canada,Japan and *** data demonstrate that Chinese children’s lead exposure remains a public health problem that requires additional effort and resources.

关键词： child gasoline lead surveillance

A dual channel perturbation particle filter algorithm based on GPU acceleration

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Journal of Systems Engineering and Electronics 2018年第4期29卷 854-863页

作者： LI Fan BI Hongkui XIONG Jiajun YU Chenlong LAN Xuhui department of Graduate Air Force Early-warning College department of early Warning Intelligence Air Force Early-warning College

The particle filter（PF） algorithm is one of the most commonly used algorithms for maneuvering target tracking. The traditional PF maps from multi-dimensional information to onedimensional information during particle weight calculation, and the incorrect transmission of information leads to the fact that the particle prediction information does not match the weight information, and its essence is the reduction of the information entropy of the useful information. To solve this problem, a dual channel independent filtering method is proposed based on the idea of equalization mapping. Firstly, the particle prediction performance is described by particle manipulations of different dimensions, and the accuracy of particle prediction is improved. The improvement of particle degradation of this algorithm is analyzed in the aspects of particle weight and effective particle number. Secondly, according to the problem of lack of particle samples, the new particles are generated based on the filtering results, and the particle diversity is increased. Finally, the introduction of the graphics processing unit（GPU） parallel computing the platform, the “channel-level” and “particlelevel” parallel computing the program are designed to accelerate the algorithm. The simulation results show that the algorithm has the advantages of better filtering precision, higher particle efficiency and faster calculation speed compared with the traditional algorithm of the CPU platform.

关键词： particle filter (PF) dual channel filtering graphic pro-cessing unit (GPU) parallel operation.

Coupled dynamic model of state estimation for hypersonic glide vehicle

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1284-1292页

作者： ZHANG Kai XIONG Jiajun FU Tingting department of Graduation Air Force Early Warning Academy early Warning Intelligence department Air Force Early Warning Academy

Aiming at handling complicated maneuvers or other unpredicted emergencies for hypersonic glide vehicle tracking,three coupled dynamic models of state estimation based on the priori information between guidance variables and aerodynamics are presented. Firstly, the aerodynamic acceleration acting on the target is analyzed to reveal the essence of the target’s *** three coupled structures for modeling aerodynamic parameters are developed by different ideas: the spiral model with a harmonic oscillator, the bank model with trigonometric functions of the bank angle and the guide model with the changing rule of guidance variables. Meanwhile, the comparison discussion is concluded to show the novelty and advantage of these ***, a performance assessment in different simulation cases is presented and detailed analysis is revealed. The results show that the proposed models perform excellent properties. Moreover, the guide model produces the best tracking performance and the bank model shows the second; however, the spiral model does not outperform the maneuvering reentry vehicle(MaRV) model markedly.

关键词： hypersonic glide vehicle state estimation dynamic model aerodynamic parameter guidance variable

Effect of Social Media Celebrities on Children’s Satisfaction with Their Body Image

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International Journal of Mental Health Promotion 2022年第1期24卷 95-114页

作者： Raja Omar Bahatheg early childhood department College of EducationKing Saud UniversityRiyadh11362Saudi Arabia

This study investigated the impact of social media and media on children’s body satisfaction in early *** effect of social media and media on children’s body image and differences between girls’and boys’acceptance of their body image were explored.A questionnaire and an illustrated body satisfaction scale were distributed to a sample of 491 children in Saudi Arabia(246 girls,245 boys)aged 5-7 *** results revealed differences between children’s responses to the illustrated body satisfaction scale and *** data revealed children were satisfied with their body image(91.4%,standard deviation[SD]0.53),skin color(91.2%,SD 0.53),and weight(79.6%)and did not want to change their shape(73.7%).However,the illustrated body satisfaction scale indicated many children wanted to be like social media celebrities(37.9%),television and film celebrities(32.6%),and famous singers(25.5%).No statistically significant differences were found between girls and boys in body satisfaction,although 66.9%of boys wanted the shape of their body to be more muscular,and girls wanted blue or green eyes and blond *** study also revealed Disney princesses had a major effect on girls compared with other *** researcher recommends conducting longitudinal studies in Arab societies,particularly in Saudi Arabia,to explore the influence of celebrities on children as they ***,educational policymakers should include pictures of Arab children in the curricula instead of foreign children.

关键词： Body image social media body satisfaction pre-school children

Sensing Matrix Optimization for Random Stepped-Frequency Signal Based on Two-Dimensional Ambiguity Function

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Chinese Journal of Electronics 2024年第1期33卷 161-174页

作者： Mingjiu LYU Hao CHEN Jun YANG Xia WU Ming ZHOU Xiaoyan MA Radar NCO School Air Force Early Warning Academy department of early Warning Technology Air Force Early Warning Academy

Compressive sensing technique has been widely applied to achieve range-Doppler reconstruction of high frequency radar by utilizing sparse random stepped-frequency(SRSF) signal, which can suppress the complex electromagnetic interference and greatly reduce the coherent processing interval. An important way to improve the performance of sparse signal reconstruction is to optimize the sensing matrix(SM). However, the existing research on the SM optimization needs to design a measurement matrix with superior performance, which needs a large amount of computation and does not consider the influence of the waveform parameters design. In order to improve the superior reconstruction performance, a novel SM optimization approach for SRSF signal is proposed by using two-dimensional ambiguity function(TDAF) in this paper. Firstly, based on the two-dimensional sparse reconstruction model of the SRSFs, the internal relationship between the waveform parameters and the SM was derived. Secondly, the SM optimization problem was directly transformed into the waveform design of SRSFs. Furthermore, on the basis of analyzing the relationship between the mutual coherence matrix of SM and the TDAF matrix of SRSFs, the purpose of optimizing the SM can be achieved by designing the TDAF of the SRSFs. Based on this analysis, a sparse waveform optimization method with joint constraints of maximum and mean sidelobes of the TDAF by using the genetic algorithm was derived. Compared with the traditional SM optimization method, our method not only avoids generating a new measurement matrix, but also further reduces the complexity of the waveform optimization. Simulation experiments verified the effectiveness of the proposed method.

关键词： Correlation Computational modeling Electromagnetic interference Optimization methods Signal reconstruction High frequency radar Sensors

Multi-target tracking algorithm of boost-phase ballistic missile defense

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Journal of Systems Engineering and Electronics 2013年第1期24卷 90-100页

作者： Kangsheng Tian Feng Zhang department of Four Air Force Early Warning Academy department of Graduate Management Air Force Early Warning Academy

Considering the problem of multiple ballistic missiles tracking of boost-phase ballistic missile defense, a boost-phase tracking algorithm based on multiple hypotheses tracking （MHT） concept is proposed. This paper focuses on the tracking algo- rithm for hypothesis generation, hypothesis probability calculation, hypotheses reduction and pruning and other sectors. From an engineering point of view, a technique called the linear assignment problem （LAP） used in the implementation of M-best feasible hypotheses generation, the number of the hypotheses is relatively small compared with the total number that may exist in each scan, also the N-scan back pruning is used, the algorithm＇s efficiency and practicality have been improved. Monte Carlo simulation results show that the proposed algorithm can track the boost phase of multiple ballistic missiles and it has a good tracking performance compared with joint probability data association （JPDA）.

关键词： ballistic missile multiple hypotheses tracking (MHT),linear assignment problem (LAP) hypothesis pruning.

Method of target tracking with Doppler blind zone constraint

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Journal of Systems Engineering and Electronics 2013年第6期24卷 889-898页

作者： Wei Han Ziyue Tang Zhenbo Zhu department of Air/Space based early-warning Equipment Air Force Early Warning Academy

Doppler blind zone （DBZ） has a bad influence on the airborne early warning radar, although it has good detection performance for low altitude targets with pulse Doppler （PD） technology. In target tracking, the blind zone can cause target tracking breakage easily. In order to solve this problem, a parallel particle filter （PF） algorithm based on multi-hypothesis motion models （MHMMs） is proposed. The algorithm produces multiple possible target motion models according to the DBZ constraint. Particles are updated with the constraint in each motion model. Once the first measurement from the target which reappears from DBZ falls into the particle cloud formed by any model, the measurementtrack association succeeds and track breakage is avoided. The simulation results show that on the condition of different DBZ ranges, a high association ratio can be got for targets with different maneuverability levels, which accordingly improves the tracking quality.

关键词： Doppler blind zone (DBZ) track breakage particle filter (PF) multi-hypothesis motion model (MHMM) measurementtrack association

Comparative Evaluation and Performance Analysis of Heat Exchangers Featured with Peened Surface

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Journal of Thermal Science 2025年第1期34卷 50-61页

作者： DINESHBABU Chinnadurai SHIVA SANKARAN Nallasamy VENKATESH RAJA Krishnan VENKATESH Rathinavelu department of Mechanical Engineering Kongunadu College of Engineering and Technology department of Mechanical Engineering Selvam College of Technology department of Mechanical Engineering Sona College of Technology department of Mechanical Engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical Sciences (SIMATS)Saveetha University

Heat exchangers have the potential for various engineering applications,and their performance is enriched by surface *** proposed system enriches the heat exchanger's performance by adapting a peened stainless steel（SS） surface blasted with copper,grinding,sand,and *** influences peened SS surface modified with a copper blast,grinding,sandblast,and iron blast on the surface morphology of shell and tube heat exchanger surface（STHE） is analyzed via tungsten heated cathode electron gun featured scanning electron microscope and observed coarse grain *** SS surface featured STHE performance is experimentally evaluated by different flow rates（30,60,90,and 120 L/min） underwater fluid medium functioned by the temperature ranges of 25-75℃ and its results are compared with computational fluid dynamic（CFD）/heat transfer research（HTRI） analyzed *** 60 L/min flow rate was spotted as an optimum value for both shell and tube side *** STHE is operated with a 60 L/min flow rate under the different peened surfaces and evaluated its Stanton number,Nusselt number,logarithmic mean temperature difference（LMTD）,overall heat transfer coefficient,number of transfer units（NTU）,effectiveness,and exergy *** iron blasted SS peened surface was observed to have better SHTE performance like Stanton number（0.0012）,Nusselt number（2180）,reduced LMTD of 31℃,improved overall heat transfer co-efficient of 2400 W/（m2·K）,better NTU of 0.5532,good effectiveness value of 0.451 62,and hiked exergy efficiency of 10% respectively.

关键词： penned surface performance analysis shell and tube heat exchanger stainless steel

Missing Value Imputation for Radar-Derived Time-Series Tracks of Aerial Targets Based on Improved Self-Attention-Based Network

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Computers, Materials & Continua 2024年第3期78卷 3349-3376页

作者： Zihao Song Yan Zhou Wei Cheng Futai Liang Chenhao Zhang department of early Warning Intelligence Early Warning AcademyWuhan430019China

The frequent missing values in radar-derived time-series tracks of aerial targets(RTT-AT)lead to significant challenges in subsequent data-driven ***,the majority of imputation research focuses on random missing(RM)that differs significantly from common missing patterns of *** method for solving the RM may experience performance degradation or failure when applied to RTT-AT *** autoregressive deep learning methods are prone to error accumulation and long-term dependency *** this paper,a non-autoregressive imputation model that addresses the issue of missing value imputation for two common missing patterns in RTT-AT is *** model consists of two probabilistic sparse diagonal masking self-attention(PSDMSA)units and a weight fusion *** learns missing values by combining the representations outputted by the two units,aiming to minimize the difference between the missing values and their actual *** PSDMSA units effectively capture temporal dependencies and attribute correlations between time steps,improving imputation *** weight fusion unit automatically updates the weights of the output representations from the two units to obtain a more accurate final *** experimental results indicate that,despite varying missing rates in the two missing patterns,our model consistently outperforms other methods in imputation performance and exhibits a low frequency of deviations in estimates for specific missing *** to the state-of-the-art autoregressive deep learning imputation model Bidirectional Recurrent Imputation for Time Series(BRITS),our proposed model reduces mean absolute error(MAE)by 31%~50%.Additionally,the model attains a training speed that is 4 to 8 times faster when compared to both BRITS and a standard Transformer model when trained on the same ***,the findings from the ablation experiments demonstrate that the PSDMSA,the weight fusion unit,cascade network design

关键词： Missing value imputation time-series tracks probabilistic sparsity diagonal masking self-attention weight fusion