刘翔打破室内60米栏亚洲记录全程时间特征分析

本文通过录像分析法、数量统计等方法对2012年2月刘翔参加世界田联英国伯明翰室内田径分站赛的比赛全程技术与自己在2007年在卡危斯鲁跑室内60米栏比赛录像进行解析,对比分析内容包括:全程速度、起跑反应、起跑至第一栏、全程过栏、栏间节奏、下第五栏至终点等技术环节时间参数,来分析刘翔打破亚洲室内60米栏记录的真正原因,并为刘翔即将开始的室外赛突破进行预测,借此对我国许多跨栏运动员起到借鉴和参考作用。

基于网络时间协议的被动式路由器指纹识别技术

作为网络安全的重要内容，面向路由器等核心网络设备的指纹识别研究正逐渐兴起。针对网络应用中主流路由器的识别技术，本文提出一种基于网络时间协议（NTP）特征分析的被动式路由器指纹识别方法。该方法以NTP协议为研究对象，提取NTP报文中的时间特征，通过计算其时间间隔来刻画报文处理时间，进行路由器型号的识别与区分，最后利用支持向量机对所提出的特征进行训练学习，对四类典型思科路由器的识别准确率能达到98．9％。实验结果表明，该方法能够对路由器型号进行有效地被动识别，可为后期路由设备特征指纹的研究提供技术参考与借鉴。

“错峰出行”制度的作用机理及交通可行性研究——以上海为例

“错峰出行”制度的实施是一个复杂的系统工程问题,概念化实施不仅不能产生好的交通效益,反而可能会使城市交通状况更加恶化.本文介绍了“错峰出行”在国内实施的现状和基本概念,描述了该制度对交通系统的作用机理,从时间分布、空间分布和交通结构比例三个方面分析了该制度实施给交通系统带来的综合影响.以上海为例,从城市主要道路基础设施的交通时间特征、公共交通客流量的时间特征出发,对上海实施“错峰出行”的交通可行性进行了分析.最后,根据上海交通发展的背景和交通时间特征的分析结果,给出了“错峰出行”在近期不可行的结论.

Feature extraction and damage alarming using time series analysis

Aiming at the problem of on-line damage diagnosis in structural health monitoring （SHM）, an algorithm of feature extraction and damage alarming based on auto-regressive moving-average （ARMA） time series analysis is presented. The monitoring data were first modeled as ARMA models, while a principalcomponent matrix derived from the AR coefficients of these models was utilized to establish the Mahalanobisdistance criterion functions. Then, a new damage-sensitive feature index DDSF is proposed. A hypothesis test involving the t-test method is further applied to obtain a decision of damage alarming as the mean value of DDSF had significantly changed after damage. The numerical results of a three-span-girder model shows that the defined index is sensitive to subtle structural damage, and the proposed algorithm can be applied to the on-line damage alarming in SHM.

基于LSTM神经网络的喀什地区流腮预测模型

流行性腮腺炎(流腮)是一种好发于儿童的急性呼吸道传染病,流行病预测研究工作有助于为有关部门提供科学的辅助决策。以新疆喀什地区2005—2020年流腮病例为研究对象,完成了流行性病学特征分析,分析结果显示,11月为疾病高发时间段,月平均病例数达135例;喀什地区疏附县为病例高发地区,年平均病例达到219例。建立了基于长短期记忆(LSTM)神经网络的喀什地区的流腮预测模型,经过与梯度提升回归树(GBRT)模型对比,实验结果显示LSTM模型的预测精度更高,RMSE误差最小,数值为16.3。基于LSTM模型的流腮预测模型具有良好的预测能力,在实际应用中能够为有关部门提供一定的辅助决策支持。

SPATIAL DISTRIBUTION AND VARIATION TENDENCY OF DROUGHTS AND FLOODS IN HUNAN PROVINCE DURING THE PAST 36 YEARS

Using the 1970-2005 annual precipitation and evaporation data at 80 gauge stations across Hunan province,this work analyzes the spatial distribution and variation tendency of the local droughts and floods using linear regression,wavelet analysis,abrupt change,clusters,Empirical Orthogonal Function (EOF) and rotated EOF (REOF).Results show that there are four dry areas and three wet areas in Hunan.The whole province exhibits a moistening trend except some small areas in western,eastern and southern Hunan.The most prominent feature of annual precipitation is that the whole province basically displays a consistent variation tendency,as far as the dominant EOF mode is concerned.In addition,the spatial features of the other EOF modes include dry-wet differences,e.g.wet (or dry) in the north versus dry (or wet) in the south,wet (or dry) in the center and dry (or wet) in the surrounding areas.The distribution of the ratios of evaporation to precipitation exhibits both common features as well as spatial differences,which can be classified into four types:South Hunan,North Hunan,Northeast Hunan,and Central Hunan.There is an abrupt change from dry to wet patterns in the early 1990s.Generally,the drought-flood distribution presents variations of three periods.In the late 2000s,Hunan province will be in a period of drought,followed by a period of flood.

Metastasis to the gallbladder:A single-center experience of 20 cases in South Korea

AIM： To evaluate the clinicopathologic characteristics of patients with metastases to the gallbladder （MGBs）. METHODS： We performed a single-center retrospective study of 20 patients with MGBs diagnosed pathologically from 1999 to 2007. RESULTS： Among 417 gallbladder （GB） malignancies, 20 （4.8%） were MGBs. The primary malignancies originated from the stomach （n = 8）, colorectum （n = 3）, liver （n = 2）, kidney （n = 2）, skin （n = 2）, extrahepatic bile duct （n = 1）, uterine cervix （n = 1）, and appendix （n = 1）. Twelve patients were diagnosed metachronously, presenting with cholecystitis （n = 4）, abdominal pain （n = 2）, jaundice （n = 1）, weight loss （n = 1）, and serum CA 19-9 elevation （n = 1）; five patients were asymptomatic. The median survival after the diagnosis of MGB was 8.7 mo. On Cox regression analysis, R0 resection was the only factor associated with a prolonged survival [hazard ratio （HR）： 0.01, P = 0.002]; presentation with cholecystitis was associated with poor survival （HR： 463.27, P = 0.006）. CONCLUSION： MGBs accounted for 4.8% of all pathologically diagnosed GB malignancies. The most common origin was the stomach. The median survival of MGI3 was 8.7 mo.

Gustiness and coherent structure under weak wind period in atmospheric boundary layer

Statistical analysis of turbulent and gusty characteristics in the atmospheric boundary layer under weak wind period has been carried out.The data used in the analysis were from the multilevel ultrasonic anemometer-thermometers at 47 m,120 m,and 280 m levels on Beijing 325 m meteorological tower.The time series of 3D atmospheric velocity were analyzed by using conventional Fourier spectral analysis and decompose into three parts:basic mean flow(period > 10 min),gusty disturbances(1 min < period < 10 min)and turbulence fluctuations(period < 1 min).The results show that under weak mean wind condition:1)the gusty disturbances are the most strong fluctuations,contribute about 60% kinetic energy of eddy kinetic energy and 80% downward flux of momentum,although both the eddy kinetic energy and momentum transport are small in comparison with those in strong mean wind condition;2)the gusty wind disturbances are anisotropic;3)the gusty wind disturbances have obviously coherent structure,and their horizontal and vertical component are negatively correlated and make downward transport of momentum more effectively;4)the friction velocities related to turbulence and gusty wind are approximately constant with height in the surface layer.

Analysis of Abnormal Characteristics of Regional Crustal Deformation before the Menyuan MS6.4 Earthquake by GPS Continuous Data

In order to study the characteristics of crustal deformation around the epicenter before the 2016 M_S6. 4 Menyuan earthquake,the GPS continuous stations of the period from 2010 to 2016 were selected according to the observation data of the tectonic environment monitoring network in Chinese Mainland. The deformation characteristics of the crust before the earthquake were discussed through inter-station baseline time series analysis and the strain time series analysis in the epicentral region. The results show that a trend turn of the baseline movement state around the epicenter region occurred after 2014,and the movement after 2014 reflects an obvious decreasing trend of compressional deformation.During this period,the stress field energy was in a certain accumulation state. Since the beginning of 2014,the EW-component linear strain and surface strain rate weakened gradually before the earthquake. It shows that there was an obvious deformation deficit at the epicentral area in the past two years,which indicates that the region accumulated a high degree of strain energy before the earthquake. Therefore,there was a significant background change in the area before the earthquake. The results of the study can provide basic research data for understanding the seismogenic process and mechanism of this earthquake.

Sandwich-Boomerang attack on reduced round CLEFIA

CLEFIA(named after the French word "Clef" meaning "Key") is an efficient,highly secure block cipher proposed by SONY Corporation in the 14 th International Workshop on Fast Software Encryption(FSE-2007) and many cryptanalyses have been used to analyze it.According to the property of CLEFIA,a new technique Sandwich-Boomerang cryptanalysis is used on it.An 8-round Sandwich-Boomerang distinguisher of CLEFIA is constructed using the best differential characteristic of CLEFIA.And then,based on the distinguisher,an attack against 10-round CLEFIA is proposed.The number of chosen plaintexts required is 2^(119)(or 2^(120)) and the time complexity is 2^(120)(or 2^(121)).Compared with a 7-round impossible Boomerang distinguisher presented by Choy in the 4th International Workshop on Security(IWSEC-2009),the differential characteristics used in the attack are all the best ones,so it is believed that the attack is the best result that the Boomerang attacks can get on CLEFIA at present.

The Research of Fractal Characteristics of the Electrocardiogram in a Real Time Mode

The article presents the results of recent investigations into Holter monitoring of ECG, using non-linear analysis methods. This paper discusses one of the modern methods of time series analysis--a method of deterministic chaos theory. It involves the transition from study of the characteristics of the signal to the investigation of metric （and probabilistic） properties of the reconstructed attractor of the signal. It is shown that one of the most precise characteristics of the functional state of biological systems is the dynamical trend of correlation dimension and entropy of the reconstructed attractor. On the basis of this it is suggested that a complex programming apparatus be created for calculating these characteristics on line. A similar programming product is being created now with the support of RFBR. The first results of the working program, its adjustment, and further development, are also considered in the article.

Self-Similar Characteristic for the Ramp Structures of Wind Speed

Time series of wind speed are composed of large and small ramp structures. Data analysis reveals a power law relation between the linear slope of ramp structures and the time scale. This suggests that these ramp structures of wind speed have a self-similar characteristic. The lower limit of the self-similar scale range was 2 s. The upper limit is unexpectedly large at 27 rain. Data are collected from grassland, city, and lake areas. Although these data have different underlying surfaces, all of them clearly show a power law relation, with slight differences in their power exponents.

Face Recognition Using LDA with Wavelet Transform Approach

Linear Discriminant Analysis （LDA） is one of the principal techniques used in face recognition systems. LDA is well-known scheme for feature extraction and dimension reduction. It provides improved performance over the standard Principal Component Analysis （PCA） method of face recognition by introducing the concept of classes and distance between classes. This paper provides an overview of PCA, the various variants of LDA and their basic drawbacks. The paper also has proposed a development over classical LDA, i.e., LDA using wavelets transform approach that enhances performance as regards accuracy and time complexity. Experiments on ORL face database clearly demonstrate this and the graphical comparison of the algorithms clearly showcases the improved recognition rate in case of the proposed algorithm.

Effects of Grazing on the Grassland Vegetation Community Characteristics in Inner Mongolia

The continuous increase of livestock production in Inner Mongolia has caused severe degradation of the grassland ecosystems in recent years. Previous grazing experiments have shown a wide range of vegetation responses between the biome types on a global scale, but there is still a lack of sufficient studies to discern the relative responses of a given biome type. We conducted a meta-analysis of vegetation coverage(VC), plant density(PD), total biomass(TB), above-ground biomass(AGB), under-ground biomass(UGB) and Shannon–Weaver Index(SI) in different grassland types in Inner Mongolia obtained under conditions of different grazing intensities and durations. The results showed that grazing decreased VC, TB, AGB, UGB, and PD significantly. Compared to the global and national average values, the negative effects of grazing to steppe biomass in Inner Mongolia were higher than that on the global scale, while less pronounced than that in China. TB of the meadow steppe in Inner Mongolia increased by 40% under moderate grazing intensity and duration because of compensatory growth. SI of the desert and meadow steppe showed negative linear relationships with the grazing intensity in Inner Mongolia. The percentage changes in AGB, PD, and SI to grazing showed quadratic relationships with the mean annual temperature of the experimental year. With increasing mean annual precipitation, the negative effects of grazing on UGB and SI first decreased and then increased, with that of VC and grazing showing a cubic relationship.