Estimation of free core nutation parameters and availability of computing options

The Earth’s Free Core Nutation(FCN) causes Earth tides and forced nutation with frequencies close to the FCN that exhibit resonance effects.High-precision superconducting gravimeter(SG) and very long baseline interferometry(VLBI) provide good observation techniques for detecting the FCN parameters.However,some choices in data processing and solution procedures increase the uncertainty of the FCN parameters.In this study,we analyzed the differences and the effectiveness of weight function and ocean tide corrections in the FCN parameter detection using synthetic data,SG data from thirty-one stations,and the 10 celestial pole offset(CPO) series.The results show that significant discrepancies are caused by different computing options for a single SG station.The stacking method,which results in a variation of0.24-5 sidereal days(SDs) in the FCN period(T) and 10^(3)-10^(4) in the quality factor(Q) due to the selection of the weighting function and the ocean tide model(OTM),can effectively suppress this influence.The statistical analysis results of synthetic data shows that although different weight choices,while adjusting the proportion of diurnal tidal waves involved,do not significantly improve the accuracy of fitted FCN parameters from gravity observations.The study evaluated a series of OTMs using the loading correction efficiency.The fitting of FCN parameters can be improved by selecting the mean of appropriate OTMs based on the evaluation results.Through the estimation of the FCN parameters based on the forced nutation,it was found that the weight function P_(1) is more suitable than others,and different CPO series(after 2009) resulted in a difference of 0.4 SDs in the T and of 103 in the Q.We estimated the FCN parameters for SG(T=430.4±1.5 SDs and Q=1.52×10^(4)±2.5×10^(3)) and for VLBI(T=429.8±0.7 SDs,Q=1.88×10^(4)±2.1×10^(3)).

A New Result on Regular Designs under Baseline Parameterization

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.

Application of ACP Nonlinear Math in Analyzing Arithmetic and Radiation Transmission Data (Application 1 & 2) [4-21-2024, 820P] (V)

In this study, we explore the application of ACP (asymptotic curve based and proportionality oriented) Alpha Beta (αβ) Nonlinear Math to analyze arithmetic and radiation transmission data. Specifically, we investigate the relationship between two variables. The novel approach involves collecting elementary “y” data and subsequently analyzing the asymptotic cumulative or demulative (opposite of cumulative) Y data. In part I, we examine the connection between the common linear numbers and ideal nonlinear numbers. In part II, we delve into the relationship between X-ray energy and the radiation transmission for various thin film materials. The fundamental physical law asserts that the nonlinear change in continuous variable Y is negatively proportional to the nonlinear change in continuous variable X, expressed mathematically as dα = −Kdβ. Here: dα {Y, Yu, Yb} represents the change in Y, with Yu and Yb denoting the upper and baseline asymptote of Y. dβ {X, Xu, Xb} represents the change in X, with Xu and Xb denoting the upper and baseline asymptote of X. K represents the proportionality constant or rate constant, which varies based on equation arrangement. K is the key inferential factor for describing physical phenomena.

TOA positioning algorithm of LBL system for underwater target based on PSO

For the underwater long baseline(LBL)positioning systems,the traditional distance intersection algorithm simplifies the sound speed to a constant,and calculates the underwa-ter target position parameters with a nonlinear iteration.However,due to the complex underwater environment,the sound speed changes with time and space,and then the acoustic propagation path is actually a curve,which inevitably causes some errors to the traditional distance intersection positioning algorithm.To reduce the position error caused by the uncertain underwater sound speed,a new time of arrival(TOA)intersection underwater positioning algorithm of LBL system is proposed.Firstly,combined with the vertical layered model of the underwater sound speed,an implicit positioning model of TOA intersection is constructed through the constant gradient acoustic ray tracing.And then an optimization function based on the overall TOA residual square sum is advanced to solve the position parameters for the underwater target.Moreover,the particle swarm optimization(PSO)algorithm is replaced with the tra-ditional nonlinear least square method to optimize the implicit positioning model of TOA intersection.Compared with the traditional distance intersection positioning model,the TOA intersec-tion positioning model is more suitable for the engineering practice and the optimization algorithm is more effective.Simulation results show that the proposed methods in this paper can effectively improve the positioning accuracy for the underwater target.

Obtaining accurate measurements of the sea surface height from a GPS buoy

A dedicated GPS buoy is designed for calibration and validation(Cal/Val)of satellite altimeters since 2014.In order to evaluate the accuracy of the sea surface height(SSH)measured by the GPS buoy,twelve campaigns have been done within China sea area between 2014 and 2021.In six of these campaigns,two static Global Navigation Satellite System stations were installed at distances of<1 km and 19 km from the buoy to assess how the baseline length influenced the derived SSH from the buoy solutions.The GPS buoy data was processed using the GAMIT/GLOBK software+TRACK module and CSRS-PPP tool to achieve the SSH.The SSH was compared with conventionally tide gauge(TG)data to evaluate the accuracy of the buoy with the standard deviation of the height element.The results showed that the difference in the standard deviation of the SSH from the buoy and the TG was less than 16 mm.The SSHs processed with different ephemeris(Ultra-Rapid,Rapid,Final)were not significantly different.When the baseline length was 19 km,the SSH solution of the GPS buoy performed well,with standard bias of less than 26 mm between the heights measured by the buoy and TG,meaning that the buoy could be used for Cal/Val of altimeters.The bias between the Canadian Spatial Reference System-precise point positioning tool and the TRACK varied a lot,and some of them were over 130 mm.This deemed too high to be useful for Cal/Val of satellite altimeters.Moreover,the GPS buoy solutions processed by GAMIT/GLOBK software+TRACK module were used for in-orbit Cal/Val of HY-2B/C satellites in ten campaigns.The SSH and significant wave height of the altimeters showed good agreements with the GPS buoy solutions.

Carbon emission reduction accounting method for a CCUS-EOR project

It is difficult to quantify and certify the greenhouse gas(GHG)emission reduction in the entire process of a project of carbon capture,utilization and storage(CCUS)-enhanced oil recovery(EOR).Under the methodological framework for GHG voluntary emission reduction project,the carbon emission reduction accounting method for CCUS-EOR project was established after examining the accounting boundaries in process links,the baseline emission and project emission accounting methods,and the emission and leakage quantification and prediction models,in order to provide a certification basis for the quantification of GHG emission reduction in the CCUS-EOR project.Based on the data of energy consumption,emission and leakage monitoring of the CCUS-EOR industrial demonstration project in Jilin Oilfield,the net emission reduction efficiency is determined to be about 91.1%at the current storage efficiency of 80%.The accounting and prediction of carbon emission reduction for CCUS-EOR projects with different concentrations and scales indicate that within the project accounting boundary,the certified net emission reduction efficiency of the low-concentration gas source CCUS-EOR projects represented by coal-fired power plants is about 37.1%,and the certified net emission reduction efficiency of the high-concentration gas source CCUS-EOR projects represented by natural gas hydrogen production is about 88.9%.The proposed method is applicable to the carbon emission reduction accounting for CCUS-EOR projects under multiple baseline scenarios during the certification period,which can provide decision-making basis for the planning and deployment of CCUS-EOR projects.

Influence of water conservancy project on runoff in the source region of the Yellow River and wetland changes in the Lakeside Zone,China

The source area of the Yellow River(SAYR),located above the Huangheyan hydrological station,is important for ecological preservation and water source conservation in the Yellow River Basin.In this area,the impact of water conservation projects on the hydrology and the ecological environment is pivotal in protecting water resources and alpine vegetation ecosystems.This study investigates the impact of the Yellow River Source Hydropower Station on the runoff and ecological evolution of the SAYR,along with the underlying mechanism,using extensive datasets encompassing long-term meteorological,hydrological and remote sensing data from various time periods.Results show that,over the long term,precipitation is the primary factor driving runoff variations in the SAYR.Nevertheless,from 1990 to 2020,there is a notably inconsistent relationship between precipitation and runoff.After the completion of the Yellow River Source Hydropower Station in 2001,the water level of Eling Lake experienced and elevation of 2–3 m,leading to a gradual recovery of runoff.In addition,the basin's water balance shifted from a negative to a positive equilibrium,oscillating with changes in lake water levels.Consequently,the overflow zone of the Tangchama alluvial–proluvial fan in the upper reaches of the lakeshore shifted by 500 m,and marsh wetlands expanded by 20.78 km^(2).The increased storage of lakes and groundwater in the SAYR is the key controlling factor for the runoff recovery,changes in the basin's water balance,and enhancements in lakeshore vegetation ecology.Under the geological background of the Qinghai–Tibet Plateau's upliftment and intensified upstream river erosion,the basin experienced a substantial water imbalance due to declining discharge base levels,which is the most critical factor behind runoff attenuation in the SAYR towards the end of the 20th century.The construction of the hydropower station objectively raised the drainage base level of the basin,thereby positively contributing to the preservation of water balance,runoff stability,and the enhancement of swamps and wetlands along the lakeshore.

Prevalence of gastroesophageal reflux disease in children with extraesophageal manifestations using combined-video,multichannel intraluminal impedance-pH study

BACKGROUND Gastroesophageal reflux disease(GERD)might be either a cause or comorbidity in children with extraesophageal problems especially as refractory respiratory symptoms,without any best methods or criterion for diagnosing it in children.AIM To evaluate the prevalence of extraesophageal GERD using conventional and combined-video,multichannel intraluminal impedance-pH(MII-pH),and to propose novel diagnostic parameters.METHODS The study was conducted among children suspected of extraesophageal GERD at King Chulalongkorn Memorial Hospital between 2019 and 2022.The children underwent conventional and/or combined-video MII-pH.The potential parameters were assessed and receiver operating characteristic was used for the significant parameters.RESULTS Of 51 patients(52.9%males),aged 2.24 years were recruited.The common problems were cough,recurrent pneumonia,and hypersecretion.Using MII-pH,35.3%of the children were diagnosed with GERD by reflux index(31.4%),total reflux events(3.9%),and symptom indices(9.8%)with higher symptom recorded in the GERD group(94 vs 171,P=0.033).In the video monitoring group(n=17),there were more symptoms recorded(120 vs 220,P=0.062)and more GERD(11.8%vs 29.4%,P=0.398)by symptom indices.Longest reflux time and mean nocturnal baseline impedance were significant parameters for diagnosis with receiver operating characteristic areas of 0.907(P=0.001)and 0.726(P=0.014).CONCLUSION The prevalence of extraesophageal GERD in children was not high as expected.The diagnostic yield of symptom indices increased using video monitoring.Long reflux time and mean nocturnal baseline impedance are novel parameters that should be integrated into the GERD diagnostic criteria in children.

基于Baseline模型的刮板输送机健康评估

对刮板输送机进行可靠健康评估是保证工作面高效开采的关键。针对某煤矿综采工作面刮板输送机提出一种基于Baseline模型的健康评估方法。该方法采用长短时记忆(LSTM)深度神经网络建立运行参数的Baseline模型,预测正常的数值和故障发生上、下限阈值。在此基础上建立了真实值与预测值的6种偏差计算方法和设备健康评估机制。最后融合机头电机、机尾电机、机头减速器和机尾减速器的评估结果,完成刮板输送机运行健康综合评估。

SBAS-InSAR技术监测青藏高原季节性冻土形变

冻土的冻结和融化的反复交替会造成地质环境与结构的破坏,从而导致房屋和道路等地面工程建筑物的地基破裂或者塌陷,还会引起山体滑坡、洪水暴发以及冰川移动等.因此,监测冻土形变对确保冻土区工程建筑的稳定性和安全性,同时保证冻土区社会经济可持续发展具有重要的意义.目前,在冻土监测方面并没有能大面积监测冻土形变时间演化情况的有效方法,本文提出将InSAR技术中的小基线集方法(SBAS-InSAR)应用于监测冻土来获取其形变时间序列中.考虑到冻土形变呈现明显的季节性特征,本文提出利用周期形变模型来代替传统SBAS方法中的线性形变模型,从而更好地分离出高程残差和大气误差.利用ENVISAT卫星获取的21景ASAR影像图作为实验数据,采用改进的SBAS技术成功获取了青藏高原从羊八井站至当雄站铁路段冻土区的地表形变时间序列图,揭示了该冻土区从2007年到2010年的季节性形变演化情况.通过与研究地区温度变化的联合分析,发现所得到的地表形变结果与冻土的物理变化规律非常吻合,证明了SBAS-InSAR技术在冻土形变监测中具有良好的发展应用前景.

基于短基线集方法(SBAS-INSAR)技术的山区城市地面沉降监测研究——以攀枝花为例

基于合成孔径雷达干涉(interferometric synthetic aperture radar,INSAR)技术的山区城市地面沉降研究,因地形复杂、植被覆盖等因素开展较少。首次在攀枝花市,利用12景2009-2010ENVISAT ASAR数据,采用短基线集方法开展大范围、长时间监测。结果表明,攀枝花市东区地面沉降较大,沉降的平均速率高达48 mm/年;西区沉降较小,沉降平均速率10 mm/年。推测原因多为城市化建设所致地面荷载;而市东北方向的露天矿区,因连续开采所致,不同时期同一地点的地表变化,导致高相干点在此区域分散稀疏,不能表明是否有沉降现象。

基于聚类分析的微博用户标签自动生成

基于用户发表的微博内容进行标签的自动生成,主要研究的是基于聚类分析的用户标签自动生成。本文首先介绍用到的关键技术:聚类技术和Text Tank,提出了Baseline系统,接下来详细说明了基于聚类分析的标签自动生成方法,最后通过实验对该方法进行了分析和评价。实验结果表明,该方法生成的用户标签能够有效地解决同义标签的堆积问题,使得生成的标签能够在更多的维度上体现用户的兴趣。

聚焦爬行中网页爬行算法的改进

因特网的迅速发展对万维网信息的查找与发现提出了巨大的挑战。对于大多用户提出的与主题或领域相关的查询需求,传统的通用搜索引擎往往不能提供令人满意的结果网页,为了克服通用搜索引擎的以上不足,提出了面向主题的聚焦爬虫的研究思路和方法。该文针对聚焦爬虫这一研究热点,对现今聚焦爬虫的爬行方法(主要是网页分析算法和网页搜索策略)做了深入分析和对比,提出了一种改进的聚焦爬行算法。这种基于类间规则的聚焦爬行方法借助baseline聚焦爬虫的架构,应用朴素的贝叶斯分类器并利用主题团间链接的统计关系构造规则找到在一定链接距离内的"未来回报"页面,并通过实验对该算法的性能进行分析、评价,证明其对聚焦爬虫的爬行收获率和覆盖率有很好的改善。

Baseline——一种容忍与检测DoS/DDoS攻击的被动方法(英文)

提出一种检测DoS/DDoS攻击(拒绝服务攻击/分布式拒绝服务攻击)的“Baseline”服务体系结构,并实现了其中关键的“Shepherd”检测算法。该体系结构通过把服务及其质量是否受到影响的判断指标交由具体的通信进程来定义而具有较强的适应性,可以与各种现有入侵检测系统很好地结合且不给宿主系统增加过多的开销。同时相比其他DoS/DDoS检测方式,Baseline服务无须对Internet路由基础设施作出更改来提供支持,是一种十分可行的DoS/DDoS检测方案。在理想情况下,Baseline服务可以做到对DoSDDoS入侵零误报。

高效液相色谱测定饲料氨基酸基线漂移问题的研究

高效液相色谱测定氨基酸,由于是梯度洗脱,容易产生基线漂移,造成测定结果偏低,分离度差,保留时间变化,通过使用仪器Learn baseline和baseline功能,可以使基线走直,测定结果可靠.

Prophylactic captopril reduces perioperative myocardial ischemia in dogs

Perioperative myocardial ischemia(PMI) is mainly caused by increasesin sympathetic nervous system activity due to stress,which results incoronary endothelial dysfunction,hence that it is hypothesized thatcaptopril may improve PMI.In our study,twenty mongrel dogs wererandomized for four groups;group Ⅰ:control,group Ⅱ:myocardialinfarction (MI) model,Group Ⅲ:MI+partial gastrectomy,group Ⅳ:MI+captopril+partial gastrectomy.Myocardial infarction wasproduced by ligation of left anterior descending coronary artery exceptthe group Ⅰ.In the group Ⅲ and Ⅳ,the hemodynamics,plasmaendothelin (ET) and nitric oxide (NO) on baseline,pre-andpostoperation were investigated two weeks after MI All animals werekilled by overdose anesthetic and their cardiac samples of non-infarction area taken for examining nitric oxide synthase (NOS)mRNA expression levels in vascular endothelial cells.Results:ingroup Ⅲ,the operation decreased the maximal rate of left ventricularpressure rise (LV+dP/dtmax),cardiac index (CI) and plasma No level,and increased left ventricular end diastolic pressure (LVEDP),time-course of isovolumic pressure fall (T constant),total peripheralresistance (TPR) and the levels of ET.In group Ⅳ,40 minutes afteradminstration of captopril,the TPR was decresed,and the t constantwas incresed significantly.The operation attenuated the TPR and Tconstant,but didn’t affect the other values.In situ hybridization it wasshowed that the expression levels of NOS mRNA was the highest ingroup Ⅰ,lower in groups Ⅱ and Ⅳ,and the lowest in group Ⅲ.Conclusions:1.Partial gastrectomy performed after myocardialinfarction may induce left ventricular systolic and diastolic dysfunction,and may produce coronary endothelial dysfunction;2.captopril canimprove left ventricular dysfuction and endothelial dysfunctioninduced by noncardiac operation.

基于MAX+plusII 10.0 Baseline的数字电路设计

讨论 MAX+plus II10 .0 Baseline的功能和特点 ,提出以 VHDL 设计语言为手段、以 MAX+plus II10 .0Baseline为平台的数字电路的设计方法。

应用DSSAT模型预测宁夏春小麦产量演变趋势

对DSSAT作物模型中的CERES-Wheat小麦模型,在排除虫害和病害影响条件下,以宁夏永宁站永良4号春小麦为样本进行品种参数调试及模拟验证,确定品种参数。宁夏平罗站同一品种15年生育期特征及潜在产量模拟验证结果表明,产量值、开花天数预测结果较好,生理成熟天数模拟误差较大。宁夏黄河灌区25 km×25 km共计39个格点1961-1990年Baseline气候情景（无考虑温室气体效应）及构建的2011-2100年A2（CO2约1%的中高排放）、B2（CO2约0.5%的中低排放）气候情景潜在产量模拟对比结果表明,Baseline气候情景下39个格点的平均潜在产量6 428 kg/hm^2,A2情景下的2011-2040、2041-2070、2071-2100平均产量分别为6 235、5 869、5 211 kg/hm^2,与Baseline年相比均为减产趋势,分别减产为3%、8%、19%。B2情景下的2011-2040、2041-2070、2071-2100平均产量分别为6 2195、977、5721 kg/hm^2,与Baseline年相比均为减产趋势,分别减产3%、7%、11%。高排放的减产率比低排放要大。

基于Baseline SVD主动学习算法的推荐系统

推荐系统是一种解决信息过载的新型技术,为了解决推荐系统中新用户带来的冷启动问题,提出一种基于主动学习的推荐系统。主动学习方法能有效减少需要标记的样本数量,快速建立模型,在此选择将主动学习方法和Baseline SVD推荐算法结合起来,通过记录模型训练得到的预估评价的改变程度,认为改变最大的样例即是最具有信息量的样例,供新用户标记,并重新训练模型。通过与其他选择策略进行实验比较,证实了该方法确实有效解决了新用户带来的冷启动问题。

Baseline JPEG压缩器在Xilinx FPGA上的设计与实现

由于近年来胶囊内窥镜需求的发展,以及FPGA在小型化和低功耗的技术进步,在内窥镜系统中应用FPGA为核心的解决方案已经成为可能。在目前的FPGA数字胶囊系统,以及未来用于胶囊窥镜的专用集成电路中,图像数据压缩都是重要组成部分。本文使用Verilog对普遍应用的Baseline JPEG压缩核进行封装并在FPGA进行实现和验证,并给出了电路设计和测试结果。在Xilinx Spartan LX9 FPGA上,所实现的Baseline JPEG压缩器达到最高166 MHz的时钟频率。