Positioning-control Based on Trapezoidal Velocity Curve for High-precision Basis Weight Control Valve

Traditionally, basis weight control valve is driven by a constant frequency pulse signal. Therefore, it is difficult for the valve to match the control precision of basis weight. Dynamic simulation research using Matlab/Simulink indicates that there is much more overshoot and fluctuating during the valve-positioning process. In order to improve the valve-positioning precision, the control method of trapezoidal velocity curve was studied. The simulation result showed that the positioning steady-state error was less than 0.0056%, whereas the peak error was less than 0.016% by using trapezoidal velocity curve at 10 positioning steps. A valve-positioning precision experimental device for the stepper motor of basis weight control valve was developed. The experiment results showed that the error ratio of 1/10000 positioning steps was 4% by using trapezoidal velocity curve. Furthermore, the error ratio of 10/10000 positioning steps was 0.5%. It proved that the valve-positioning precision of trapezoidal velocity curve was much higher than that of the constant frequency pulse signal control strategy. The new control method of trapezoidal velocity curve can satisfy the precision requirement of 10000 steps.

Cross-ocean GPS long distance rapid static positioning methods

The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data preprocessing and quality control, long distance integer ambiguity resolution and static Kalman filter parameter estimation. Effective data processing method of cross-ocean GPS long baseline rapid static positioning had been proposed. Through the analysis of practical examples of coastal and ocean, the feasibility of cross-ocean GPS long distance rapid static positioning based on the method is testified and verified. The results show that the accuracy of one-hour single baseline static positioning for the 500 - 600 km distance can be better than 10cm in the three-dimensional coordinates ocean environment. , which can suffice static positioning accuracy in the special

Double-Epoch Algorithm in Rapid Positioning Using Single Frequency GPS Receivers

A new algorithm, called as Double-Epoch Algorithm CDEA) is proposed in GPSrapid positioning using two epoch single frequency phase data in this paper. Firstly, the structurecharacteristic of the normal matrix in GPS rapid positioning is analyzed. Then, in the light of thecharacteristic, based on TIK-HONOV regularization theorem, a new regularizer is designed to mitigatethe ill-condition of the normal matrix. The accurate float ambiguity solutions and their MSEM (MeanSquared Error Matrix) are obtained, u-sing two epoch single frequency phase data. Combined withLAMBDA method, DEA can fix the integer ambiguities correctly and quickly using MSEM instead of thecovariance matrix of the ambiguities. Compared with the traditional methods, DEA can improve theefficiency obviously in rapid positioning. So, the new algorithm has an extensive applicationoutlook in deformation monitoring, pseudokinematic relative positioning and attitude determination,etc.

BP-LMS-based BDS-3 power system positioning method

The BeiDou-3 navigation satellite system(BDS-3)provides a full-domain high-precision positioning service for the power system to ensure safe and stable operation.However,BDS-3 power system positioning faces certain challenges,such as complex electromagnetic interference and incomplete error elimination.Herein,a back propagation neural network-improved least mean square(BP-LMS)adaptive filtering method is proposed for the BDS-3 full-domain and high-precision power system positioning,which utilizes the loss function to update the weight of the BP hidden layer,computes the pseudo compensation range,and eliminates the impact of electromagnetic interference to enhance the accuracy of power system positioning.Simulation results confirm the superior performance of BP-LMS in positioning accuracy and error elimination.Compared with LMS and normalized least mean square(NLMS),the filtering error of the proposed BP-LMS adaptive filtering method is decreased by 57.14%and 51.38%,respectively.

国家地震烈度速报江苏子系统参数测定能力评估

分析了2023年3月以来江苏地震烈度速报与预警系统震源参数测定的可靠性和精度。研究选取2022年3月1日至2023年12月20日期间江苏地区发生的98条M_(L)≥2.0地震事件,对比了新旧两套系统对同一事件的定位结果。结果显示,震中位置偏差大多数在0.3~12.1 km范围内,大部分误差属于正常范围。两套系统的震级偏差普遍较小,只有少数结果因定位台站的数量、钟差、数据噪声和干扰等因素导致偏差较大。此外,监测能力方面,新系统的监测能力整体提升M_(L)0.5,二维模拟地震定位测试方法显示定位精度也有所提升,整体来看,新系统展现出良好的实效性,能为地震分析和科学研究提供可靠的数据支持。

地铁隧道车载融合定位系统及精度校正算法研究

地铁隧道安全隐患综合检测车可实现隧道衬砌及表观隐患的快速检测。受限于地铁隧道封闭的地下环境及隧道内外部复杂的结构环境,当前隧道内单一定位技术仍存在定位精度低、累积误差大、多源采集不同步导致的定位信息“打架”等难题。本文开发了一种地铁隧道车载融合定位系统及精度校正算法,包括车载高精度编码信息采集和视觉图像采集系统、融合定位算法、精度校正算法、多源信息坐标转换矩阵等内容。相较已有定位方法,该融合定位系统可实现在直道和弯道条件下检测车车载装备和隧道安全隐患的快速动态融合定位。室内室外测试结果表明,区间的定位精度可达10 cm,地铁内直线测试区间300 m内和曲线测试区间100 m内相对误差控制小于等于0.06%。室内模型试验和现场试验结果验证了该融合定位系统及精度校正算法的有效性和稳定性,为地铁隧道安全隐患的快速检测定位和隧道安全运营提供了技术支撑。

双定位像联合FAST技术减少胸部CT辐射剂量的效果分析

目的探讨双定位像联合快速辅助扫描技术(FAST)减少胸部CT辐射剂量的效果。方法选取2020年12月至2021年5月行胸部CT检查的门诊患者160例,采用随机数字表法分为观察组和对照组,每组各80例。两组均采用FAST技术,对照组为单定位像,观察组为双定位像。比较两组CT图像的质量、信噪比(SNR)、对比噪声比(CNR)、容积CT剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效剂量(ED)及体型特异性剂量估算(SSDE)。结果观察组与对照组图像质量评分、SNR和CNR值比较,差异无统计学意义(P>0.05)。两组CTDIvol、DLP、ED及SSDE比较,差异有统计学意义(P<0.001)。结论采用双定位像联合FAST技术较常规单定位像胸部CT检查,可明显降低患者的辐射剂量,同时图像质量可以满足临床诊断要求。

Genetic mechanism of body size variation in groupers:Insights from phylotranscriptomics

Animal body size variation is of particular interest in evolutionary biology,but the genetic basis remains largely unknown.Previous studies have shown the presence of two parallel evolutionary genetic clusters within the fish genus Epinephelus with evident divergence in body size,providing an excellent opportunity to investigate the genetic basis of body size variation in vertebrates.Herein,we performed phylotranscriptomic analysis and reconstructed the phylogeny of 13 epinephelids originating from the South China Sea.Two genetic clades with an estimated divergence time of approximately 15.4 million years ago were correlated with large and small body size,respectively.A total of 180 rapidly evolving genes and two positively selected genes were identified between the two groups.Functional enrichment analyses of these candidate genes revealed distinct enrichment categories between the two groups.These pathways and genes may play important roles in body size variation in groupers through complex regulatory networks.Based on our results,we speculate that the ancestors of the two divergent groups of groupers may have adapted to different environments through habitat selection,leading to genetic variations in metabolic patterns,organ development,and lifespan,resulting in body size divergence between the two locally adapted populations.These findings provide important insights into the genetic mechanisms underlying body size variation in groupers and species differentiation.

GNSS rapid precise point positioning enhanced by low Earth orbit satellites

The Low Earth Orbit(LEO)satellites can be used to efectively speed up Precise Point Positioning(PPP)convergence.In this study,180 LEO satellites with a global distribution are simulated to evaluate their contribution to the PPP convergence.LEO satellites can give more redundant observations and improve satellite geometric distributions,particularly for a single Global Navigation Satellite System(GNSS).The convergence speed of the PPP foat solution using the Global Positioning System(GPS,G)or BeiDou Navigation Satellite System(BDS,C)single system as well as the G/C/Galileo navigation satellite system(Galileo,E)/GLObal NAvigation Satellite System(GLONASS,R)combined system with LEO satellites added is improved by 90.0%,91.0%,and 90.7%,respectively,with respect to the system without LEO satellites added.We introduced LEO observations to assist GNSS in PPP-AR(Ambiguity Resolution)and PPP-RTK(Real Time Kinematic).The success fx rate of a single system is signifcantly improved,and the Time-To-First-Fix(TTFF)of G and G/C/E is reduced by 86.4%and 82.8%,respectively,for the PPP-AR solution.We analyzed the positioning performance of LEO satellite assisted G/C/E PPP-RTK in the reference networks of diferent scales,namely diferent atmospheric delay interpolation accuracies.The success fx rate of the G/C/E combined system is improved from 86.8 to 94.9%,and the TTFF is reduced by 36.8%,with the addition of LEO satellites in the 57 km reference network.In the 110 km reference network,the success fx rate of the G/C/E combined system is improved from 64.0 to 88.6%,and the TTFF is reduced by 32.1%.GNSS PPP-RTK with adding the LEO satellites in the reference networks of diferent scales shows obvious improvement because the atmospheric correlation decreases with increasing distance from the reference networks.

垂直冲击试验台同步及快速制动液压控制系统研究

为解决垂直冲击试验台负载质量大,且易产生二次冲击的问题,针对试验台液压控制系统的关键技术要求,设计了一种双液压缸位置同步控制系统和快速反弹制动系统。首先,根据试验台的关键技术指标,综合考虑了实际工况与经济性等因素,设计出了液压控制系统原理图;然后,针对同步控制系统,利用Simulink软件设计了模糊控制器及同步控制算法模型,同时利用AMESim软件搭建了液压系统仿真模型,并对两个模型进行了联合仿真,针对反弹制动系统,利用AMESim软件进行了建模和仿真;最后,对比了模糊PID控制与常规PID控制的仿真结果;设计制造了大型垂直冲击试验台,进行了实际测试,验证了仿真结果的正确性。研究结果表明:针对实际工况下模糊PID控制方式的同步误差最大为0.09 mm,满足0.2 mm的同步精度要求,采用模糊PID控制方式对比常规PID控制方式,其有较高的同步控制精度与较强的鲁棒性;采用比例伺服阀加插装阀驱动制动器,使工作台进入快速制动的工作模式,整体响应时间为63 ms,满足100 ms的制动生效时间要求;实际同步控制系统最大同步误差为0.11 mm,满足性能指标,验证了控制方案与仿真的正确性。

快速轴位滚转试验在水平半规管良性阵发性位置性眩晕患侧诊断中的临床价值

目的探讨传统滚转试验(supine roll test,SRT)、低头-抬头试验(bow and lean test,BLT)和快速轴位滚转试验(rapid axial roll test,RART)在水平半规管良性阵发性位置性眩晕(horizontal semicircular canal benign paroxysmal positional vertigo,HSC-BPPV)责任半规管判定中的临床价值。方法选取2021年3月至2022年4月西安交通大学第一附属医院HSC-BPPV患者328例,根据不同的变位试验分为SRT组(113例)、BLT+SRT组(104例)和RART+SRT组(111例),BLT+SRT组和RART+SRT组分为2个阶段,第一阶段进行BLT或RART,第二阶段进行SRT。比较不同组别眼震引出率,采用Kappa一致性检验比较BLT/RART与SRT眼震引出结果的一致性。结果328例患者中,男95例,女233例,年龄18~86岁,平均(55.5±13.8)岁。RART+SRT组眼震引出率高于BLT+SRT组和SRT组(94.59%比81.73%比74.34%);RART+SRT组第一阶段眼震引出率、第二阶段SRT眼震引出率、责任半规管判定一致比例均高于BLT+SRT组,差异均有统计学意义(P<0.05);对责任半规管判定一致的患者进行复位治疗,BLT+SRT组痊愈率为92.59%(50/54),RART+SRT组为97.96%(96/98),两组痊愈率的比较,差异无统计学意义(χ^(2)=2.645,P=0.187)。Kappa一致性检验结果显示,RART与SRT在眼震引出率方面具有较好的一致性,一致率达94.59%(Kappa=0.638,P<0.001)。结论RART具有加速度大、安全性好、眼震引出率高的特点,能够有效诱发出HSC-BPPV特征性眼震,提高半规管定侧定位的准确性,为HSC-BPPV的临床实践提供更优化的检查方案,值得在临床中广泛推广。

瓜子等不同食品中二氧化硫假阳性的快速验证及实际应用分析

目的探究快速验证瓜子等不同食品中二氧化硫假阳性及实际应用分析。方法对快速验证法采取空白实验、检出限和定量限验证、加标回收、精密度实验、阳性样品不同方法比对等方式进行方法学验证,以确保该方法的可行性。同时以瓜子等食品为研究对象,用快速验证法对GB5009.34—2022《食品安全国家标准食品中二氧化硫的测定》中酸碱滴定法检出的阳性样品进行验证,并与GB5009.34—2022离子色谱法的验证结果进行比对,最后对上述假阳性的可疑性成因进行了初步探讨分析。结果快速验证法能快速、有效地验证GB 5009.34—2022酸碱滴定法的假阳性现象,验证结果与GB 5009.34—2022离子色谱法一致。研究发现GB 5009.34—2022酸碱滴定法检测瓜子、黑木耳干出现假阳性的概率较高,部分辣椒、八角等香辛料、酱腌菜、黄花菜干等蔬菜干制品、代用茶、其他炒货类等也会出现假阳性现象。结论GB 5009.34—2022酸碱滴定法检测瓜子等食品二氧化硫会出现不同程度的微量检出现象,当结果不确定时,可用本研究的快速验证法进行快速验证,该法验证结果稳定可靠,较GB 5009.34—2022其他验证方法验证效率更高、更快。

定量装车系统偏载风险预判与过程控制研究

火车快速定量装车系统在我国煤炭装运过程中已经得到广泛应用。然而在实际操作中,由于车速的波动、煤质波动、煤块的大小形状等因素造成的堆密度波动,会导致在装车的过程中出现超偏载及撒煤等风险。针对这种情况,开展定量仓煤量与车辆位置的装车风险研究。首先,在装车系统中增设了多种传感器及先进的识别系统。这些设备能够实时、准确地捕获相关的装车数据,确保数据的完整性和准确性。然后,对采集到的大量数据进行了细致的清洗和过滤工作,以去除无用数据和噪声数据,确保数据分析的可靠性和准确性。最后,对清洗和过滤后的数据进行多维度的深度分析。通过运用先进的统计分析方法,深入挖掘了定量仓煤量与车辆位置之间的潜在关系。对定量仓煤量与车辆位置之间的关系进行研究,有助于优化装车流程,以及避免装车过程中撒煤、偏载等问题。该研究能提高整体作业效率。

DTN基于位置的RAPID路由算法

面向意向容迟网络的资源分配协议(RAPID)路由算法通过引入效能函数避免其他容迟网络(DTN)路由算法对某一性能指标的影响。然而算法中的相遇时间分布问题增加了算法的不确定性和应用局限性。针对这一问题,该文设计了新的基于位置信息的效能函数计算方法。新方法通过元数据交换获得各个节点的位置信息,采用灰色系统预测算法获得较长时间没有消息的目的节点的位置信息。通过最小化到达目的节点的时间,设计了更详细的消息复制优先级及复制规则。仿真表明,新算法能有效克服RAPID算法的问题,降低了消息复制数和平均时延,提高了消息成功递交率,网络的整体性能得到进一步提升。

月球南极巡视器多模态感知与避障方法

月球南极地区地形复杂,太阳高度角极低导致阴影区域变化大,为巡视器的自主导航提出了巨大的挑战。本工作提出一种面向月球南极的巡视器多模态感知与避障路径规划方案。一方面通过RGB相机获得全局的场景影像,进行初步的障碍物检测;另一方面利用深度相机获取实时的环境深度,通过简化的SLAM算法构建局部地图,即实时生成点云图;根据点云信息,计算路面粗糙度、坡度、阶跃信息等物理环境信息。利用上述多模态数据结合地图数据实时更新巡视器位姿和周围环境,结合使用多模态局部算法和障碍检测算法进行障碍物感知和避障决策,使巡视器能够动态调整路径。仿真结果表明该自主导航系统显著提高巡视器在复杂未知环境中的自主导航能力。

海口市南海大道快速提升改造策略研究

南海大道作为海口市贯通东西的空间发展轴心,是海口市“四横八纵”骨干路网中重要的横向干道。通过时间、空间两个维度,路网结构、转换条件、功能定位、快速系统四个思考,得出南海大道需要的是一定程度上的快速化而非快速路,提出了南海大道西段“修复”、中段“提升”、东段“贯通”的总体改造策略,有效控制建设规模和投资,形成一定程度上快速化的东西向大通道。

微生物培养体系预处理在MALDI-TOF MS快速鉴定血培养阳性病原菌的应用价值

目的分析微生物培养仪(HB&L)微生物培养体系预处理在基质辅助激光解吸电离飞行时间质谱技术(MALDI-TOF MS)快速鉴定血培养阳性样本病原菌的临床应用价值。方法收集2022年1月至2022年12月安阳市人民医院实验室常规方法鉴定的120份血培养报警后单一细菌感染的阳性样本,所有样本均接受HB&L微生物培养体系预处理、分离胶促凝管法预处理,将传统方法的鉴定结果作为“金标准”对照,运用MALDI-TOF MS鉴定。对比HB&L微生物培养体系预处理、分离胶促凝管法预处理下MALDI-TOF MS快速鉴定的鉴定率;另外对比HB&L微生物培养体系预处理、分离胶促凝管法在不同分值下MALDI-TOF MS样本细菌菌属快速鉴定结果。结果HB&L微生物培养体系预处理下MALDI-TOF MS快速鉴定例数为116例,鉴定率为96.67%;分离胶促凝管法预处理下MALDI-TOF MS快速鉴定例数为92例,鉴定率为76.67%,两种预处理方法鉴定率对比差异有统计学意义(P<0.05);在3.000~2.300分值下HB&L微生物培养体系MALDI-TOF MS样本细菌菌属快速鉴定率均高于分离胶促凝管法,差异有统计学意义(P<0.05);在2.299~2.000、1.999~1.700、<1.700分值下两种预处理方法菌属鉴定率对比差异无统计学意义(P>0.05)。结论HB&L微生物培养体系是MALDI-TOF MS快速鉴定血培养阳性样本病原菌优质的预处理方法,可大幅提升鉴定率,值得应用。

梅毒携带者并发神经梅毒的危险因素分析

目的 探讨梅毒携带者并发神经梅毒的危险因素。方法选择2016年2月—2023年6月仪征市人民医院神经内科收治的64例梅毒携带者,其中并发神经梅毒者33例为研究对象。针对快速血浆反应素试验(rapid plasma reagin test,RPR)持续阳性时间、RPR滴度、脑脊液梅毒螺旋体颗粒凝集试验(treponema pallidum particle agglutination assay,TPPA)结果、脑脊液白蛋白水平、合并人类免疫缺陷病毒(human immunodeficiency virus,HIV)感染、脑脊液白细胞计数、颅内压、是否接受正规梅毒治疗等进行单因素及多因素logistic回归分析。结果 RPR持续阳性时间1年以上,RPR滴度≥1∶8,脑脊液TPPA结果阳性,脑脊液白细胞计数升高为梅毒携带者并发神经梅毒的独立危险因素(P <0.05),接受正规梅毒治疗为预防梅毒携带者并发神经梅毒的保护因素(P<0.05)。结论 对于梅毒RPR试验持续阳性时间超过1年且滴度≥1∶8,脑脊液TPPA结果阳性合并脑脊液白细胞计数升高者,其发生神经梅毒的概率显著增高,故此类患者应更为积极地接受规律治疗。

Multi-antenna synchronized global navigation satellite system receiver and its advantages in high-precision positioning applications

The multi-antenna synchronized global navi- gation satellite system receiver is a high precision, low cost, and widely used emerging receiver. Using this type of receiver, the satellite and receiver clock errors can be eliminated simultaneously by forming between antenna single-differences, which is equivalent to the conventional double-difference model. However, current multi-antenna synchronized global navigation satellite system receiver products have not fully realized their potential to achieve better accuracy, efficiency, and broader applications. This paper introduces the conceptual design and derivable products of multi-antenna synchronized global navigation satellite system receivers involving the aspects of attitude determination, multipath effect mitigation, phase center variation correction, and ground-based carrier phase wind- up calibration. Through case studies, the advantages of multi-antenna synchronized global navigation satellite system receivers in high-precision positioning applications are demonstrated.

基于机器视觉的瓶装饮料液位识别与定位

为实现饮料生产线PET瓶装饮料液位检测系统集成化和简单化,使用机器视觉方法取代传统传感器触发PET瓶装饮料液位检测程序,实现生产线PET瓶装饮料液位快速识别定位,提出了基于改进YOLOv7的生产线PET瓶装饮料液位快速识别与定位方法。在原YOLOv7的基础上,将原SPPCSPC池化金字塔结构改进为更快的SPPFCSPC结构,并使用SIoU损失函数对原有损失函数进行改进。实测试验结果表明,改进YOLOv7液位识别模型对包含有色彩失真和噪点的PET饮料瓶身、瓶装饮料液位识别精度为98.9%、96.3%,并且单幅图像识别并框定时间均长为12.1 ms。在采集图像样本色彩失真、多噪点和图像旋转情况下,模型仍能实现高精度瓶装饮料液位识别与定位。