CFOSAT SWIM波谱仪中法产品差异性分析

中法海洋卫星(China-France Oceanography SATellite,CFOSAT)搭载了世界上第一颗专门探测二维海浪谱的雷达,即SWIM(Surface Waves Investigation and Monitoring)波谱仪。该雷达能通过旋转6个不同波束的方式扫描海面从而得到二维海浪谱信息,并通过控制天线旋转速度来控制沿轨向二维谱的分辨率。中法双方都会发布相同软件处理的波谱仪2级产品,但由于中法双方接收站位置不同、地面数据处理时输入的气象辅助数据源不完全一致,因此双方发布的2级产品有一定差异,这给波谱仪产品的应用带来不确定性。为了明晰不同数据下载源得到的相同版本波谱仪产品之间的差异,选取2024年3月中法相关单位发布的最新版本2级数据,采用5.0 s、3.0 s、1.0 s和0.1 s的时间匹配窗口,获取中法数据不同匹配时间下二维海浪谱3个波浪参数的一致性对比结果。结果表明:有效波高比较稳定,在半个地理单元的空间差别下仍然保持几乎不变的精度;随着匹配时间增大,主波波长和主波波向的差别越来越大,匹配时间为5.0 s时,二者分别达到约21.5 m和46.5°的差异,匹配时间为0.1 s时,其差异很小,表明中法不同地面处理系统输入的气象辅助数据源差异而引起的产品差别可以忽略。

Swimming velocity of spherical squirmers in a square tube at finite fluid inertia

The three-dimensional lattice Boltzmann method(LBM)is used to simulate the motion of a spherical squirmer in a square tube,and the steady motion velocity of a squirmer with different Reynolds numbers(Re,ranging from 0.1 to 2)and swimming types is investigated and analyzed to better understand the swimming characteristics of microorganisms in different environments.First,as the Reynolds number increases,the effect of the inertial forces becomes significant,disrupting the squirmer's ability to maintain its theoretical velocity.Specifically,as the Reynolds number increases,the structure of the flow field around the squirmer changes,affecting its velocity of motion.Notably,the swimming velocity of the squirmer exhibits a quadratic relationship with the type of swimming and the Reynolds number.Second,the narrow tube exerts a significant inhibitory effect on the squirmer motion.In addition,although chirality does not directly affect the swimming velocity of the squirmer,it can indirectly affect the velocity by changing its motion mode.

Solumbra技术和SWIM技术治疗脑卒中的疗效对比

目的评估Solumbra技术和SWIM技术治疗急性缺血性脑卒中(acute ischemic stroke,AIS)的有效性与安全性。方法回顾性分析191例AIS病例资料,根据手术方式分为Solumbra组(n=97)和SWIM组(n=94)。应用倾向性评分匹配法(propensity score matching,PSM)将两组患者按1∶1配比。对比匹配后两组患者临床相关指标、术后不同时间点美国国立卫生院卒中量表(the National Institutes of Health Stroke Scale,NIHSS)评分、侧支循环改善情况及并发症发生率。结果经PSM匹配,有50对患者匹配成功。Solumbra组患者取栓>2次占比与住院时间均高于SWIM组,预后良好占比低于SWIM组(P<0.05)。Solumbra组患者术后7d及术后2周NIHSS评分均低于SWIM组(P<0.05)。并发症发生率Solumbra组为20.00%,SWIM组为38.00%,Solumbra组低于SWIM组(P<0.05)。结论Solumbra技术和SWIM技术取栓治疗各有优势,临床可充分结合患者实际病情,针对性选择取栓方式。

Examining Stroke Efficiency:How an Olympian Outperformed a Masters Swimmer in Backstroke

This study investigates whether eo SwimBetter can differentiate the efficiency and stroke pattern between elite and non-elite swimmer.The subjects are a three-time Olympian and USA Masters registered swimmers during a 50-meter backstroke while using the 3D accelerometer.We find the eo SwimBetter is able to differentiate between an elite swimmer and novice level Masters swimmer.In addition to a stopwatch,the eo SwimBetter provides swimmer sam coaches with an additional measurement tool to effectively measure swim performance.

基于SWIM模型模拟气候变化对青海湖布哈河流域水文过程的影响

本文基于青藏高原地区气候变化的预估结果,利用SWIM模型模拟了该地区最具有代表性的布哈河流域在未来3个时期(2016—2035年、2046—2065年和2081—2100年)径流深、实际蒸散量和深层渗漏量的变化及其时空格局.结果表明:1)模型对布哈河流域径流的模拟结果较为理想,表明SWIM模型在高寒地区有较强的适用性;2)随着降水的增加和气温的持续上升,流域的径流深和实际蒸散量在2100年前会持续增加,而深层渗漏量则先下降后上升;3)气候变化对流域水文过程的影响有季节差异性,其对深层渗漏量的影响集中于7、8月,而对径流深和实际蒸散量的影响主要在6—8月期间;4)流域各水文过程及其在不同时期的变化呈现一定的空间差异性.

SWIM水文模型在王家坝地区的适用性评估

[目的]评估SWIM水文模型参数值变化对模拟王家坝地区径流精度的影响,为王家坝地区洪涝灾害的预报和减灾提供科学支持,并为SWIM在其他地区应用提供参照。[方法]利用王家坝地区率定期(1959—1978年)和验证期(1979—2008年)的实测数据,得到最优参数组合后定量分析SWIM在王家坝地区对7个可率定参数的敏感性。[结果]率定期和验证期模拟日径流量纳西效率分别达0.79和0.81,相对误差分别为22%和7.8%。随着参数thc(计算潜在蒸腾时对大气散射率的校准因子)值的增大,相对误差显著下降,其对thc值的敏感性强于纳西系数。roc_4(河道汇流系数)比roc_2(河道汇流系数)更能影响日径流,而roc_2对径流影响汛期大于非汛期。随着参数sccor(饱和传导率校正因子)值的增大,模拟精度在汛期提高非汛期降低。[结论]率定后的SWIM模型在王家坝地区适用性良好;SWIM模拟结果在王家坝地区对thc,cnum_1(曲线数法代码为1时,CN条件1),cnum_3(曲线数法代码为1时,CN条件3),roc_2,roc_4,sccor取值变化比较敏感,对参数bff(基流因子),gwq()(初始地下流对径流量的贡献)和abf()(地下水阿尔法因子)取值变化不敏感。

SWIM技术治疗急性大脑中动脉M1段闭塞患者首次血管再通的影响因素分析

目的探讨应用SWIMI技术治疗大脑中动脉M1段闭塞的急性缺血性脑卒中(AIS)患者实现闭塞血管首次再通的影响因素。方法回顾分析2017年2月至2019年11月在浙江医院卒中中心应用SWIM技术进行血管内治疗的急性大脑中动脉M1段闭塞并最终实现血管再通患者的临床资料。记录患者的性别、年龄、基础疾病、有无吸烟史、血脂水平、入院时及术后7d美国国立卫生研究院卒中量表(NHSS)评分、改良Rankin量表(mRS)评分、支架打开后锚定远端M2段血管的直径及其是否为优势主干,根据mRS评分评价患者术后90d预后情况。根据改良脑梗死溶栓分级(mTICI)将入组患者分为首次再通组和非首次再通组,采用单因素分析比较两组间各指标的差异,并分析各因素与血管首次再通的相关性。结果共纳入64例患者,其中血管首次再通29例,非首次再通35例。两组患者的性别、年龄以及高血压、糖尿病、高脂血症、有吸烟史、缺血性心脏病、心房颤动所占比例比较差异均无统计学意义,两组术后7d NIHSS评分均较术前有所改善,首次再通组治疗前后的NIHSS评分差值明显高于非首次再通组(分:9.33±2.39比7.70±2.85.P<0.05).首次再通组患者90d预后良好率略高于非首次再通组,但差异无统计学意义[68.9%(20/29)比51.4%(18/35).P>0.05]。与非首次再通组比较,首次再通组支架远端错定优势主干所占比例明显升高[(75.9%(22/29)比42.9%(15/35)].支架远端错定血管直径明显增大[mm:1.70(1.58.1.90)比1.50(1.32.1.73)].差异均有统计学意义(均P<0.05)。相关性分析显示,支架远端锚定优势主干、支架锚定M2段血管直径均与闭塞血管首次再通,呈正相关(Kenall's tau-b相关系数分别为0.333、0.276.P值均为0.008)。结论在利用SWIM技术治疗大脑中动脉M1段闭塞的AIS患者中,支架远端锚定优势主干和支架锚定M2段血管直径与闭塞血管首次再通相关。

基于隐半马尔可夫模型的SWIM应用层DDoS攻击的检测方法

针对广域信息管理(SWIM)系统受到应用层分布式拒绝服务(DDoS)攻击的问题,提出了一种基于隐半马尔可夫模型(HSMM)的SWIM应用层DDoS攻击的检测方法。首先采用改进后的前向后向算法,利用HSMM建立动态异常检测模型动态地追踪正常SWIM用户的浏览行为;然后通过学习和预测正常SWIM用户行为得出正常检测区间;最后选取访问包的大小和请求时间间隔为特征进行建模,并训练模型进行异常检测。实验结果表明,所提方法在攻击1和攻击2情况下检测率分别为99.95%和91.89%,与快速前向后向算法构建的HSMM相比,检测率提升了 0.9%。测试结果表明所提方法可以有效地检测SWIM系统应用层DDoS攻击。

Where is the rudder of a fish?:the mechanism of swimming and control of self-propelled fish school

Numerical simulation and control of self- propelled swimming of two- and three-dimensional biomimetic fish school in a viscous flow are investigated. With a parallel computational fluid dynamics package for the two- and three-dimensional moving boundary problem, which combines the adaptive multi-grid finite volume method and the methods of immersed boundary and volume of fluid, it is found that due to the interactions of vortices in the wakes, without proper control, a fish school swim with a given flap- ping rule can not keep the fixed shape of a queue. In order to understand the secret of fish swimming, a new feedback con- trol strategy of fish motion is proposed for the first time, i,e., the locomotion speed is adjusted by the flapping frequency of the caudal, and the direction of swimming is controlled by the swinging of the head of a fish. Results show that with this feedback control strategy, a fish school can keep the good order of a queue in cruising, turning or swimming around circles. This new control strategy, which separates the speed control and direction control, is important in the construction of biomimetic robot fish, with which it greatly simplifies the control devices of a biomimetic robot fish.

SWIM技术治疗大血管闭塞性脑梗死的围手术期护理

目的总结颅内支撑导管辅助Solitaire支架取栓+吸栓技术(Solitaire FR with intracranial support catheter for mechanical thrombectimy,SWIM)治疗大血管闭塞性脑梗死的围手术期护理要点。方法对80例急性大血管闭塞性脑梗死患者采用SWIM技术进行取栓和吸栓相结合开通血管,加强围手术期护理管理。结果 80例患者中,75例血管成功再通,5例血管再通不佳,术中医护配合良好。结论快速有效地完善术前准备、密切观察病情、熟练的术中护理配合、仔细认真的术后护理有利于血管再通治疗顺利完成,改善患者预后。

SWIM在空管信息系统上的应用研究

随着航空事业的不断发展,对于空中信息管理的要求也在逐步提高,在这种发展背景下,SWIM技术得到了高度重视。文章从当前空管系统信息化存在的主要问题入手,介绍SWIM的特点,并提出了具体系统的设计方案以及实现方式。

空管新技术——SWIM

本文介绍了系统级信息管理(SWIM)的运行概念,从功能、技术体系和组件模型等多方面描述了SWIM的体系结构,重点介绍了面向服务的架构(SOA)、信息技术基础设施功能,以及SWIM技术在空管中的应用。

基于SWIM模型的洱海流域产流模拟研究

利用DEM、土地利用图、气象水文观测数据,使用SWIM模型对洱海流域产流进行了模拟,比较模拟值和观测值得到效率系数为0.49,总流量相对误差为-18%。

Adaptive Swimming of Underwater Snake-like Robot in Different Underwater Environment

Hydrodynamic force is an important factor that affects the performance of underwater vehicle.Adapting to the current underwater environment by changing its shape is an important feature of underwater snake-like robots(USLR).An experiment was implemented to verify the swimming along the straight line of USLR.A simulation platform is also established for the analysis of the swimming of USLR.To figure out adaptive swimming of USLR to different underwater environments,the relationships between CPG parameters and maximum swimming speed have been discussed,and the switching between different swimming modes has been implemented.

Research Status and Development Trend on the Physiological Comfort of Swimwear

The classification of the swimwear, the development of the swimwear and market situation were introduced. The main factors affecting the physiological comfort and the research status were presented. With the combination of objective and subjective evaluation methods, it is pointed out that on the physical comfort the research of wet swimwear is one of the development trends.

A Reanalysis of the Two Swimmers Problem, as Frequent Model of Michelson’s Interferometric Experiment Demonstrating that Transversal Path Is Not an Isosceles but a Right Triangle and the Race Will End in a Tie

The article initially reviews various works describing the physical model (PM) of Michelson’s interferometric experiment (ME), represented by the race between two swimmers Sw1, Sw2 (or boats, or planes, or sound signals, etc.). The two swimmers must each swim the same distance, but Sw1 will swim along the river flow, and Sw2 will swim perpendicularly to this direction. In all such works, it is considered that Sw2’s path will require less time and that it will reach the start point first. However, in this work, it has been determined that in order to make this possible, Sw2 must not observe the orthogonality rule of his start direction. This action would be deceitful to the arbiters and thus considered as non-fair-play towards Sw1. The article proves by swimming times calculus, that if the fair-play rules are observed, then the correct crosswise path (in water reference frame) is a right triangle instead of the isosceles triangle considered by Michelson. Consequently, the two times shall be perfectly equal and the race ends in a tie, and the myth of Sw2 as the race winner shall be debunked. Note that the same result shall also be applicable to Michelson’s interferometric experiment (ME) as well as to any similar experiment. Therefore, utilising the isosceles triangle as the transversal path in PM and also in ME is an erroneous act.

Cancer risk assessment from exposure to trihalomethanes in tap water and swimming pool water

We investigated the concentration of trihalomethanes （THMs） in tap water and swimming pool water in the area of the Nakhon Path- om Municipality during the period April 2005-March 2006. The concentrations of total THMs, chloroform, bromodichloromethane, dibromochloromethane and bromoform in tap water were 12.70-41.74, 6.72-29.19, 1.12-11.75, 0.63-3.55 and 0.08-3.40 μg/L, respectively, whereas those in swimming pool water were 26.15-65.09, 9.50-36.97, 8.90-18.01, 5.19-22.78 and ND-6.56 μg/L, respectively. It implied that the concentration of THMs in swimming pool water was higher than those in tap water, particularly, brominated-THMs. Both tap water and swimming pool water contained concentrations of total THMs below the standards of the World Health Organization （WHO）, European Union （EU） and the United States Environmental Protection Agency （USEPA） phase Ⅰ, but 1 out of 60 tap water samples and 60 out of 72 swimming pool water samples contained those over the Standard of the USEPA phase Ⅱ. From the two cases of cancer risk assessment including Case Ⅰ Non-Swimmer and Case Ⅱ Swimmer, assessment of cancer risk of nonswimmers from exposure to THMs at the highest and the average concentrations was 4.43×10^-5 and 2.19×10^-5, respectively, which can be classified as acceptable risk according to the Standard of USEPA. Assessment of cancer risk of swimmers from exposure to THMs at the highest and the average concentrations was 1.47×10^-3 and 7.99×10^-4, respectively, which can be classified as unacceptable risk and needs to be improved. Risk of THMs exposure from swimming was 93.9%-94.2% of the total risk. Cancer risk of THMs concluded from various routes in descending order was： skin exposure while swimming, gastro-intestinal exposure from tap water intake, and skin exposure to tap water and gastro-intestinal exposure while swimming. Cancer risk from skin exposure while swimming was 94.18% of the total cancer risk.

Experimentation of Fish Swimming Based on Tracking Locomotion Locus

There are many kinds of swimming mode in the fish world, and we investigated two of them, used by cyprinids and bulltrout. In this paper we track the locomotion locus by marks in different flow velocity from 0.2 m·s^-1 to 0.8 m·s^-1. By fit the data above we could find out the locomotion mechanism of the two kinds of fish and generate a mathematical model of fish kine- matics. The cyprinid fish has a greater oscillation period and amplitude compared with the bulltrout, and the bulltrout changes velocity mainly by controlling frequency of oscillation.

广域信息管理SWIM信息安全技术标准研究

广域信息管理SWIM(System Wide Information Management)是下一代空中交通管理系统NGATM的信息共享机制,其主要核心服务之一是信息安全保障。文章根据国际民航组织ICAO制定的相关标准,从SWIM信息安全核心服务入手,研究了SWIM安全架构,分析了以Web服务安全标准为主的SWIM安全服务和基础设施所应遵循的安全技术标准,对SWIM数据安全和隐私保护具有重要意义。

Propulsion Modeling and Analysis of a Biomimetic Swimmer

We have studied a biomimetic swimmer based on the motion of bacteria such as Escherichia coli (E. coli) theoretically andexperimentally. The swimmer has an ellipsoidal cell body propelled by a helical filament. The performance of this swimmer wasestimated by modeling the dynamics of a swimmer in viscous fluid. We applied the Resistive Force Theory (RFT) on this modelto calculate the linear swimming speed and the efficiency of the model. A parametric study on linear velocity and efficiency tooptimize the design of this swimmer was demonstrated. In order to validate the theoretical results, a biomimetic swimmer wasfabricated and an experiment setup was prepared to measure the swimming speed and thrust force in silicone oil. The experimentalresults agree well with the theoretical values predicted by RFT. In addition, we studied the flow patterns surrounding thefilament with a finite element simulation with different Reynolds number (Re) to understand the mechanism of propulsion. Thesimulation results provide information on the nature of flow patterns generated by swimming filament. Furthermore, the thrustforces from the simulation were compared with the thrust forces from theory. The simulation results are in good agreement withthe theoretical results.