高速铁路基于安全性的最优运营速度评估

为有效避免安全事故的发生,科学评估高速铁路基于安全性的最优运营速度。在解析我国高速铁路速度目标值的基础上,分析人员、车辆、轨道和环境4个方面,建立基于安全性的高速铁路运营速度评估模型,并采用层次分析法(AHP)评估运营速度,进而界定最优运营速度,最后以京沪高铁为例分析其基于安全性的最优运营速度,验证高速铁路安全性运营速度综合评估模型的有效性。结果表明:当前我国高铁安全性最优营运速度为300~350 km/h。

基于遗传算法的道路交通事故车辆碰撞速度评估

为了解决当前道路交通事故车辆碰撞速度较难评估准确的问题,本文引入遗传算法和深度学习模型,提出了一套针对道路交通事故车辆碰撞速度的评估系统。该系统由硬件与软件组成,硬件主要由视频监控、图像采集和通信传感构成,软件由用户界面和底层评估算法构成。通过将二者进行结合,建立了一种道路交通事故车辆碰撞速度的评估方法。首先,对道路车辆碰撞实际场景、业务逻辑和需求,进行分析,形成工程目标和标准,以设计对应的评估系统构架。然后,深入研究遗传算法特性、和深度学习原理,结合速度评估需求,开发出道路交通事故车辆碰撞速度的评估算法和对应的系统软件。通过将其集成到落地设备中,并进行场景功能性测试和稳定性测试。经过反复验证,所提方法具有更好的评估性能与准确度,可以更好地应用于工程领域。

滚动轴承振动速度的评估

通过对滚动轴承零件滚动表面形状偏差影响轴承振动机理的分析 ,建立了在测振状态下以这种偏差为激励的轴承外圈在测振方向的受迫振动的数学模型 ,通过对激励模型的分析 ,求出受迫振动数学模型的解及一些未知参数。通过分析与推导 ,给出了在已知轴承零件形状偏差的条件下 ,滚动轴承振动速度的数学模型。附图 1幅 ,参考文献

舰船速度信息的不确定度评估

对测量不确定度概念做出简要介绍,并将此概念用于舰船速度信息的可信度评估中。在考虑某一不确定度因素影响的条件下,推算出了舰船速度信息的扩展不确定度评估结果。

一种混合CPU和GPU的图像金字塔数据重采样评估模型

在大规模图像可视化应用中,经过四叉树预处理,建立多分辨率图像金字塔索引,以支持对不同分辨率图像的快速读取及显示。但是在显示图像分辨率与金字塔中保存图像分辨率不一致情况下,依然需要通过图像重采样来获得指定分辨率图像。一般重采样过程可以通过基于CPU或者GPU的重采样方法来完成。论文通过建立RECG(resampling evalua-tion on CPU and GPU)模型根据图像大小及缩放要求来评估其在CPU和GPU中重采样效率,据此选择基于CPU或者GPU的重采样方式,并且在此基础上建立了CPU-GPU图像块缓存策略。试验表明:根据RECG模型,对于不同的重采样比例,采取不同的重采样方式,有效地加速了重采样速度。

基于手机移动速度的HCS高铁分层应用研究

阐述了基于手机移动速度评估的HCS重选/切换算法的基本原理及如何应用于高铁3G网络。广州联通在武广高铁3G专网及沿线公网实施了HCS小区分层,启用了HCS重选/切换算法,并通过实际测试结果验证解决了高铁专网邻区设置存在的高铁用户掉公网后一直无法返回专网导致用户感知差的问题,也解决了部分高铁小区因非高铁用户过度占用导致的功率拥塞问题。

基于弱监督学习卷积神经网络的心脏按压评估

传统的基于加速度波形积分的心脏胸外按压评估方法受噪声和积分时延影响,在计算距离时存在较大误差,评估效果不理想。为此,在弱监督学习策略与波形分割的基础上,提出了一种基于一维卷积神经网络的心脏按压加速度波形识别算法,实验结果表明,一维卷积神经网络达到了99.4%的正确率,明显优于传统的积分方法和BP神经网络算法。进一步采用Grad-CAM方法对评估结果进行可视化分析,发现卷积神经网络所关注的特征集中于开始按压至按压到达平衡位置,以及此次按压松手后反向加速度达到最大值至下一次按压开始这2个阶段的加速度波形变化情况。此外该评估模型不再需要对按压距离进行精确测距,因而不受按压遮挡、电磁波干扰等因素的影响,可以实时检测按压是否规范有效,在复杂环境中也具有较高的鲁棒性,在医疗急救领域中具有一定的实用价值。

靶板厚度对破片声发射信号特征的影响研究

为研究铝合金靶板厚度对靶板声发射信号特征参数的影响,对直径8 mm球形破片侵彻不同厚度铝合金靶板进行数值模拟研究,获得靶板侵彻过程中的声发射信号。仿真分析不同速度下靶板厚度对破片侵彻过程中声发射信号特征参数的变化,研究发现:靶板厚度在3 mm~10 mm范围的声发射信号特征值幅度随破片速度的增大而增大;根据靶板厚度与靶板声发射信号特征参数的关系,选择合适厚度靶板对破片声发射信号进行分析。

温阳利水、化瘀泄浊法延缓慢性肾功能衰竭进展临床研究

目的观察温阳利水、化瘀泄浊法对慢性肾组能衰竭(CRF)进展的延缓作用。方法将65例CRF患者随机分为2组,对照组(32例)予低蛋白饮食、控制高血压及对症治疗,治疗组(33例)在对照组治疗基础上加服温阳利水、化瘀泄浊中药。以计算2组血清肌酐(SCr)值升高1倍所经历时间(月)的方法评估CRF的进展速度。结果治疗组SCr由(300.5±99.2)μmol/L升高至(602.0±199.6)μmol/L历时(27.6±9.1)月,对照组SCr由(296.3±96.8)μmol/L升高至(598.8±198.4)μmol/L历时(17.2±5.7)月,2组比较差异有显著性(P<0.01)。结论在低蛋白饮食和控制高血压的基础上加用温阳利水、化瘀泄浊中药可使CRF进展速度明显延缓。

稳定化处理

Damping a hybrid stepping motor with estimated position and velocity,Grid current regulation of a three-phase voltage source inverter with an LCL input filter,Torsional interaction studies on power system compensated by SSSC and fixed capacitor,A multivariable new control solution for increased long lines voltage restoration stability during black startup,

Surface-mounted bender elements for measuring horizontal shear wave velocity of soils

The bender element testing features its in-plane directivity, which allows using bender elements to measure the shear wave velocities in a wider range of in-plane configurations besides the standard tip-to-tip alignment. This paper proposed a novel bender element testing technique for measuring the horizontal shear wave velocity of soils, where the bender elements are surface- mounted and the axes of the source and receiver elements are parallel to each other. The preliminary tests performed on model ground of silica sand showed that, by properly determining the travel distance and time of the shear waves, the surface-mounted bender elements can perform as accurately as the conventional "tip-to-tip" configuration. Potentially, the present system provides a promising nondestructive tool for characterizing geomaterials and site conditions both in laboratory and in the fields.

Fast Evaluation of Degradation Degree of Organic Coatings by Analyzing Electrochemical Impedance Spectroscopy Data

The degradation coefficient is proposed to evaluate the degradation degree of organic coatings by directly anaIyzing the Bode plots of the electrochemical impedance spectroscopy （EIS） data. This paper investigated the degradation of phenolic epoxy coating/tinplate system by EIS and the degradation coefficient value, which correlates well with the results of breakpoint frequency and variation of phase angle at 10 Hz. Furthermore, the degradation process was confirmed by scanning electron microscope （SEM） and scanning probe microscopy （SPM）. It is concluded that degradation coefficient can be used for the fast evaluation of degradation degree of organic coatings in practical appli- cations.

Modified sensorless vector control system of IM based on flux observer

This paper presents a speed sensorless vector control system for induction machine (IM),which is based on a flux observer. According to vector control theory of IM,the q-axis rotor flux converging on zero is utilized for speed estimation. Additionally this system solved the online identification of stator resistance by d-axis flux error. The advantages of the proposed system are simplicity and avoidance of the problems caused by only using a voltage model. The effectiveness of the proposed system has been verified by simulation and experimentation.

EVALUATION OF CORRECTIONS ON TURBULENT FLUXES OBTAINED BY EDDY COVARIANCE METHOD IN HIGH WINDS

This paper investigates processing of fast-response data and corrections of turbulent fluxes obtained by using eddy covariance method based on data collected at an offshore observation tower during three Cold-intrusion(CI)events in the South China Sea in 2010. This study presents the data processing procedure in detail and compares frictional velocities(u*), sensible heat fluxes(H) and latent heat fluxes(LE) yielded by using different averaging periods and different coordinate rotation methods; evaluates the sonic temperature correction for sensible heat flux and the Webb correction for latent heat flux as a function of 10 m wind speed(u10) during the CIs. The results show(1) that the different averaging periods of 30 min and 10 min cause biases of u*(H, LE) within 5%(15%, 62%). The values of u*(H,LE) averaged from 30 mins are mostly larger than those averaged from 10 mins. We suggest that the averaging period of 10 min is not sufficiently long to capture all scale eddies and recommend 30 min averaging period in calculating turbulent fluxes using eddy covariance method during CIs;(2) that the values of u*(H, LE) obtained from double rotation(DR2) and those obtained from planar fit rotation(PF) have good agreements and correlation coefficients between them are larger than 0.99. Because PF method requires unchanged environment and it is easier to apply DR2 method, we suggest DR2 coordinate rotation method in processing fast-response data; and(3) that the median values of frictional velocity(sensible heat flux and latent heat flux) binned according to 2 m s^(-1) intervals of u_(10) increase(decrease,increase) by less than 9%(4%, 10%) by Coriolis corrections(sonic temperature corrections, Webb corrections), which decreases(decreases, increases) with increasing u10 when u10 are 5-17 m s^(-1).

Improvement of Pseudo-static Method for Slope Stability Analysis

traditional In this paper, two drawbacks pseudo-static method （vertical of the slice method） in the slope stability evaluation have been studied. First, the sliding mass is divided into vertical slices according to this method, which is irrational to some extent in the seismic design of slope. Second, only peak ground acceleration （PGA） is considered, and the effects of shaking frequency and duration on slope stability are neglected. And then, based on the theory of elastic wave and the summarized geological model, this paper put forwards an improved method of pseudo-method by using the theory of elastic wave and Hilbert-Huang transform. The improved pseudostatic method gives reasonable considerations to the time-frequency effects of seismic wave and its rationality has been verified by the shaking table test. This method can evaluate the safety of a slope, the happening time and the scale of landslides. At the same time, this method also can improve the high accuracy of the evaluation of the safety of the slope.

The Effect of Working Speed on Indices Used for the Evaluation of Seedbed Conditions

Crop establishment largely depends on the methods of tillage for seedbed preparation. Seedbed conditions and related problems have recently attracted considerable interest for research. The intensity of the soil compaction achieved because of tillage is related to the working speed of the implement used. The effect of working speed on indices used for the evaluation of seedbed preparation （index of soil texture, actual tillage depth, soil bulk density and the proposed index of leveling） were investigated by applying four different systems of tillage and using different tillage implements. The relationships of the indices investigated to working speed are also presented graphically for all tillage implements used. All relationships were found to be linear with the working speed and the corresponding coefficients of determination were very close to unity. Useful conclusions, which may be used by extension services for the selection of the proper working speed of the implements used for seedbed preparation, are reached. Finally the general conclusion is that reciprocating harrows may be introduced into energetic tillage systems for seedbed preparation.

A GIS-based Modeling Approach for Fast Assessment of Soil Erosion by Water at Regional Scale, Loess Plateau of China

The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of precipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units （FAUs） to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. Arclnfo GIS was used to integrate all essential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau.

Seismic considerations for spent nuclear fuel storage in dry casks

To aid the United States Nuclear Regulatory Commission,Sandia National Laboratories (SNL) was contracted to investigate the seismic behavior of typical dry cask storage systems. Parametric evaluations characterized the sensitivity of calculated cask response characteristics to input parameters. The parametric evaluation investigated two generic cask designs (cylindrical and rectangular),three different foundation types (soft soil,hard soil,and rock),and three different casks to pad coefficients of friction (0.2,0.55,0.8) for earthquakes with peak ground accelerations of 0.25g,0.6g,1.0g and 1.25g. A total of 1 165 analyses were completed,with regression analyses being performed on the resulting cask response data to determine relationships relating the mean (16 % and 84 % confidence intervals on the mean) to peak ground acceleration,peak ground velocity,and pseudo-spectral acceleration at 1 Hz and 5 % damping. In general,the cylindrical casks experienced significantly larger responses in comparison to the rectangular cask. The cylindrical cask experienced larger top of cask displacements,larger cask rotations (rocking),and more occurrences of cask toppling (the rectangular cask never toppled over). The cylindrical cask was also susceptible to rolling once rocking had been initiated,a behavior not observed in the rectangular cask. Cask response was not overly sensitive to foundation type,but was significantly dependent on the response spectrum employed.

Analysis and evaluation of band-limited ray tracing method

From the analysis and the contrast of band-limited ray tracing method based on Kirchhoff integral, it was found that the method performs many approximations in the derivation process and omits the derivative term of the phase factor in the Kirchhoff integral. Numerical calculations and analysis show that the omission of cor-relation terms in Kirchhoff integrals has a non-negligible effect on the calculation results, and the different terms in the Kirchhoff integral have different effects on different frequency ranges. The method can be applied to ve-locity models containing complex interfaces without changing waves and continuous media. the velocity model and can be extended to elastic waves and continuous media.

More than mimicry？ Evaluating scope for flicker-fusion as a defensive strategy in coral snake mimics

Coral snakes and their mimics often have brightly colored banded patterns, generally associated with warning colora- tion or mimicry. However, such color patterns have also been hypothesized to aid snakes in escaping predators through a ＂flicker-fusion＂ effect. According to this hypothesis, banded color patterns confuse potential predators when a snake transitions from resting to moving because its bands blur together to form a different color. To produce this motion blur, a moving snake＇s bands must transition faster than the critical flicker-fusion rate at which a predator＇s photoreceptors can refresh. It is unknown if coral snakes or their mimics meet this requirement. We tested this hypothesis by measuring the movement speed and color pat- terns of two coral snake mimics, Lampropeltis triangulum campbelli and L. elapsoides, and comparing the frequency of color transitions to the photoreceptor activity of the avian eye. We found that snakes often produced a motion blur, but moving snakes created a blurring effect more often in darker conditions, such as sunrise, sunset, and nighttime when these snakes are often active. Thus, at least two species of coral snake mimics are capable of achieving flicker-fusion, indicating that their color patterns may confer an additional defense aside from mimicry