区域道路交通安全变化测度研究

为分析区域道路交通安全变化趋势,利用相关分析建立区域道路交通安全评价指标体系;基于数据包络分析(DEA)原理,引入偏好信息,建立面向面板数据、只有非期望输出、权重受限的道路交通安全量化评价模型;在此基础上定义道路交通安全变化测度因子,构建道路交通安全变化测度模型,分析西部地区2005年以来道路交通安全变化情况。结果表明:四川、西藏、贵州、云南、宁夏等地道路交通安全提升效率较高;西藏、新疆、宁夏等地道路交通安全提升幅度较大。青海、甘肃2省道路交通安全提升效率和幅度均较差。

融合Burg谱估计与信号变化率测度的语音端点检测

针对现有基于特征的语音端点检测方法在低信噪比及非平稳噪声下检测性能较低的问题,提出了一种融合Burg谱估计与长时段信号变化率测度(LTSV)的语音端点检测方法.该方法采用表征较长时段语音变化率的LTSV参数,较准确地反映了语音的非平稳程度.与传统基于特征的语音端点检测方法相比,该方法在低信噪比及非平稳噪声情况下的检测性能有了较大提高.并融合Burg谱估计,与传统Welch谱估计方法相比,提高了LTSV参数的区分度,从而进一步提高了检测的准确率.仿真结果表明:采用融合Burg谱估计与LTSV的语音端点检测方法在低信噪比(-10dB)及非平稳噪声情况下,与传统基于特征的语音端点检测方法相比,检测准确率普遍提高了约6%以上,说明该方法在低信噪比及非平稳噪声环境下鲁棒性更好.

基于因素分解模型的辽宁省用水变化驱动力测度及时空分异

通过构建用水变化的因素分解模型,测度了1994-2006年辽宁省用水变化驱动力的经济增长效应、产业结构效应、用水强度效应及混合效应,并对各种效应进行了时间分异分析;测度了1994-2006年辽宁省14个地级市用水变化驱动力的四种效应,对各种效应进行空间聚类,进而对各种效应进行空间分异分析。结果表明:(1)经济增长拉动了水资源利用量的增长,1994-2006年平均效应为15.92×108m3/a;而用水强度和产业结构和混合效应的变化对水资源利用量的扩张起到了一定的遏制作用,同时期年平均效应分别为-12.44×108m3/a、-1.38×108m3/a和-1.88×108m3/a;(2)在1994-2006年间,经济增长效应的平均贡献率约为42.48%,用水强度效应的平均贡献率约为31.24%,产业结构效应的平均贡献率约为12.34%,混合效应的平均贡献率为4.72%。经济增长与用水强度变化是辽宁省用水变化的决定因素;(3)经济增长效应的波动性最小,对水资源利用量变化趋势起到稳定作用,产业结构效应的波动性最大,对水资源利用量变化趋势起到冲击作用,而用水强度效应和混合效应的波动性居于二者之间,是改变水资源利用量变化趋势的动力因素;(4)各种效应的空间分异反映出一个地区的经济发展水平、产业基础、资源条件与效应的发挥存在着密切的关系,因此水资源利用量的"零增长"与"负增长"目标需要在国民经济的不断发展中实现,水资源短缺问题也最终需要在国民经济的发展中解决。研究结果对于正确理解辽宁省水资源利用量变化与经济发展之间的关系,以及产业发展政策调整及可持续发展研究具有一定的参考价值。

一种基于变权重组合的光谱相似性测度

光谱相似性测度是高光谱遥感影像信息提取的关键。在欧氏距离和光谱角余弦的基础之上提出一种变权重组合的光谱相似性测度,即光谱变化权重相似性测度。这种光谱相似性测度可根据不同地物类别自动对欧氏距离和光谱角余弦测度指标配比权重。选用标准光谱库和机载OMIS高光谱影像对SCWM进行测试,并引入误分率和混淆矩阵对分类结果进行评价。结果表明,相对于仅采用一种或两种光谱相似性测度的分类方法,光谱变化权重相似性测度具有更精细的光谱识别能力。

基于投影分类的语音端点检测方法

针对低信噪比条件下语音端点检测精度受噪声干扰严重的问题,提出了一种基于投影分类的语音端点检测方法。该方法首先利用长时语音信号变化率测度特征进行低信噪比环境中的语音特征计算,充分利用语音信号和非语音信号的不同来增强低信噪比条件下的区分度;接着,采用Fisher准则对语音和背景噪声进行分类识别,确保投影后的特征参数类内散度最小、类间散度最大。实验结果表明,方法具有较高的检测精度,在信噪比为-10 d B的白噪声干扰情况下仍然保持了86.7%以上的正确检测率。

光电成像制导中地面运动目标检测与跟踪

地面运动目标的自动检测与跟踪是对地精确打击光电成像制导中的核心任务。针对地面运动目标自动检测问题,提出了由粗到精的迭代全局运动补偿算法以补偿动平台引起的背景图像像素位移,基于变化能量测度的独立运动目标检测算法以及基于三帧序列图像的运动目标定位算法。针对地面运动目标跟踪问题,提出了融合运动特征和灰度直方图特征的粒子滤波器目标跟踪算法,实现可靠、稳定跟踪地面运动目标。利用实际航拍视频进行算法验证实验,比较了基于傅里叶-梅林变换(Fourier-Mellin transform,FMT)、Kanade-Lucas-Tomasi(KLT)特征跟踪、Harris角点和迭代全局运动补偿算法,验证了基于变化能量测度的独立运动目标检测算法和融合多特征的粒子滤波器跟踪算法的有效性。

Temporal Variations in Carbon Stock of Pinus roxburghii Sargent Forests of Himachal Pradesh,India

The present study was conducted in Solan Forest Division of Himachal Pradesh covering an area of about 57,158 ha. The aim was to estimate and assess the temporal change in carbon stock of the Chil Working Circle, in two forest ranges of the Division, Solan and Dharampur, over the period of 1956-2011. The inventory data of the working plans of Solan Forest Division from 1956-1957, 1984-1985 and 2002-2003 were used in the present study while field data for biomass estimation was collected for the year 2011.The results showed a declining trend in carbon stock over 1956-1984 period, however, an increasing trend over 1984-2002 was observed, which showed a further increase for the period 2002-2011. These fluctuating trends in the forest carbon stock can be related to increasing anthropogenic pressure on forests and the subsequent introduction of a ban on green felling envisaging efficient forest management, both of which affect the forest carbon pool significantly.

Trend in Observed and Projected Maximum and Minimum Temperature over N-W Himalayan Basin

Recently, study in past trends of climate variables gained significant consideration because of its contribution in adaptions and mitigation strategies for potential future changes in climate, primarily in the area of water resource management. Future interannual and inter-seasonal variations in maximum and minimum temperature may bring significant changes in hydrological systems and affect regional water resources. The present study has been performed to observe past(1970-2010) as well as future(2011-2100)spatial and temporal variability in temperature(maximum and minimum) over selected stations of Sutlej basin located in North-Western Himalayan region in India. The generation of future time series of temperature data at different stations is done using statistical downscaling technique. The nonparametric test methods, modified Mann-Kendall test and Cumulative Sum chart are used for detecting monotonic trend and sequential shift in time series of maximum and minimum temperature. Sen's slope estimator test is used to detect the magnitude of change over a period of time on annual and seasonal basis. The cooling experienced in annual TMax and TMin at Kasol in past(1970-2010) would be replaced by warming in future as increasing trends are detected in TMax during 2020 s and 2050 s and in TMin during 2020 s, 2050 s and 2080 s under A1 B and A2 scenarios. Similar results of warming are also predicted at Sunnifor annual TMin in future under both scenarios which witnessed cooling during 1970-2010. The rise in TMin at Rampur is predicted to be continued in future as increasing trends are obtained under both the scenarios. Seasonal trend analysis reveals large variability in trends of TMax and TMin over these stations for the future periods.

Temperature and Precipitation Variations at Two Meteorological Stations on Eastern Slope of Gongga Mountain,SW China in the Past Two Decades

Gongga Mountain, locates on the eastern edge of Tibetan Plateau of China, is the highest mountain in China except summits in Tibet. Only limited meteorological data on Gongga Mountain have been published so far. Here we present the meteorological records from two stations, Moxi Station （at 1,621.7 m above sea level （a.s.1.）, 1992- 2010） and Hailuogou Station （at 2,947.8 m a.s.l., 1988-2010）, on the eastern slope of Gongga Mountain. In the past two decades, the annual precipitation decreased while the annual mean temperature increased at Hailuogou Station. Both precipitation and temperature increased at Moxi Station. The precipitation variation on the eastern slope of Gongga Mountain is influenced by both East Asian Monsoon and Indian Monsoon, so that the precipitation concentrated between May and October. The temperature variation on the eastern slope of Gongga Mountain in the past two decades showed similar trends as that of the northern hemispheric and global. In the past two decades, the temperature increased o.35℃ and o.3℃/decade at Hailuogou Station and Moxi Station respectively, which was higher than the increase extents of northern hemispheric and global temperature. The most intense warming occurred at the first decade of 21St century. The winter temperature increased more at Hailuogou Station than at Moxi Station. A remarkable increase of temperature in March was observed with only a little precipitation at both high and low altitude stations.

The anthropogenic acceleration and intensification of flash drought over the southeastern coastal region of China will continue into the future

The frequent and rapid onset of flash drought poses a serious threat to agriculture and ecosystems.Detecting human influences on flash droughts and estimating their future risks under climate change have attracted great attention.Focusing on a record-breaking flash drought event in the southeastern coastal region of China in summer 2020,the authors found that the suppression of convective precipitation and high temperature caused by the persistent high geopotential height anomalies and land-atmosphere dry coupling were important reasons for the rapid onset and strong intensity of the flash drought.Event attribution analysis with the latest CMIP6 data showed that anthropogenic climate change has not only increased the likelihood of an onset speed and intensity like those of the 2020 flash drought event,by about 93%±20%and 18%±15%,respectively,but also increased the chance of their simultaneous occurrence,by about 86%±38%,according to their joint probability distribution.Under a business-as-usual future scenario(SSP2-4.5),the likelihood of such an onset speed,intensity,and their simultaneous occurrence will further increase,by 85%±33%,49%±8%,and 81%±48%,respectively,as compared with current climate conditions.This study highlights the importance of anthropogenic climate change for accelerating and intensifying flash drought in the southeastern coastal region of China.

Landscape change detection in Yulin prefecture

Landscape is a dynamic phenomenon that almost continuously changes. The overall change of a landscape is the result of complex and interacting natural and spontaneous processes and planned actions by man. However, numerous activities by a large number of individuals are not concerted and contribute to the autonomous evolution of the landscape in a similar way as natural processes do. There is a well-established need to detect land use and ecological change so that appropriate policies for the regional sustainable development can be developed. Landscape change detection is considered to be effectively repeated surveillance and needs especially strict protocols to identify landscape change. This paper developed a series of technical frameworks on landscape detection based on Landsat Thematic Mapper (TM) Data. Through human-machine interactive interpretation, the interpretation precision was 92.00% in 1986 and 89.73% in 2000. Based on the interpretation results of TM images and taking Yulin prefecture as a case study area, the area of main landscape types was summarized respectively in 1986 and 2000. The landscape pattern changes in Yulin could be divided into ten types.

Analysis of the Effect and Solution of Geomagnetic Room Humidity on Geomagnetic Observation

It is not easy to control humidity in a geomagnetic room. If humidity is too high or the change is too fast it will lead to an abnormal change on data. The intelligent real-time humidity analysis and monitoring system of a geomagnetic room and probe can not only monitor and display the change of humidity in the geomagnetic room and send an alarm signal when it exceeds the pre-set range, but also dehumidify intelligently. One can arbitrarily control the sensor to monitor the ambient humidity of the probe in order to ensure that the data is stable and true. The design idea and main functions of the system are introduced in the paper.

Measuring Spatio-temporal Characteristics of City Expansion and Its Driving Forces in Shanghai from 1990 to 2015

Urbanization has both direct and indirect impacts on land use change, and analyzing spatio-temporal characteristics of land use change is essential for understanding these impacts. By comparing Landsat TM images, this paper examines the changes of land use structure and landscape patterns in Shanghai from 1990 to 2015. It finds that the city doubled in size, with the growth of isolated construction land being most significant among eight land use types. A land use change matrix was established and landscape indices were selected to evaluate the change of spatial structure in Shanghai. In order to identify the main driving forces of city expansion in Shanghai, this research ran partial least square regression models to assess the impact of 10 social-economic factors on land use change of Shanghai from 1990 to 2015. It then conducted bivariate correlation analysis to explore the drivers of change of various land use types: urban settlement, rural settlement and isolated construction land. Besides quantitative analysis, this paper analyzes the influence of policy-dimensional factors in land use change. It concludes with future potential research topics on land use change in a rapidly urbanizing context.

Regression Equations for Predicting the Effect of Tine Width on Draught and Soil Translocation in Moderately Fine Textured Soil

Experiments were conducted in an indoor soil bin filled with sandy clay loam soil. Tests were carried out with tillage tines to study the effect tool width on soil disturbance and draught. Depth of operation was held constant at 35 mm and then at 70 mm while speed was varied at three levels of 1.0, 3.6 and 9.0 km/h. The widths of the tines tested were 10, 20, 31, 40, 51, 88, 126, 163 and 200 mm. The cone penetration resistance of the soil varied from 400 to 600 kPa. Draught was measured with a load cell while soil disturbance was measured with a profile meter and meter rule. Draught increased at a decreasing rate with tine width. Quadratic models best fitted the data points with high R2 values. The increase in draught was affected by the forward speed since higher draught values were obtained at higher speed. Results show that the parameters of soil disturbance increased with increase in tine width, except height of ridge （hr）, which did not show any specific trend. The specific draught was highest （10.63 N/cm） with tine T20 while Tine T1 had the least specific draught of 5.2 N/cm.

Effect of Temperature Variation on the Separation of Sesamin and Sesamolin by Simulated Moving Bed

In this work, sesamin and sesamolin is separated and purified by SMB （simulated moving bed） chromatography. Purity of sesamin and sesamolin can reach 99.2% and 99.9 %, and they can be recovered by 99.9% and 99.4%, respectively. Concentrations of the extract and raffinate was monitored and periodical change of the concentration was observed on experiment. Effects of non-linear adsorption, dead volume, and temperature on the separation are reviewed by the triangle theory to explain the periodical change of concentration. It is found that dead volume has little effect, and temperature fluctuation significantly affects thc separation by SMB. The temperature seriously affects the robust operation of SMB due to the change of Henry＇s constant, which will change the selectivity and restrain the productivity. Although the productivity in this study is only 0.0416 g/L-hr, the cost of the stationary phase used in this study is much lower than that of packed in analytical column. By using this stationary phase, the authors are still able to separate the mixture of sesamin and sesmolin. This will economically attract attention for the application of SMB to purify bioactive compounds on developing botanical drugs.

Analyzing and Forecasting Climate Change in Harbin City,Northeast China

Based on sounding data from 1975 to 2005 and TM/ETM+ remote sensing images in 1989, 2001 and 2007, the climate changes in Harbin City, Northeast China in recent 30 years were analyzed and forecasted. Results show that in the lower troposphere the meridional wind speed and mean annual wind speed decrease, and in the lower stratosphere the temperature decreases while the meridional wind speed increases significantly. In the study area, the climate is becoming warmer and wetter in the middle lower troposphere. The expansion of urban area has great effects on the surface air temperature and the wind speed, leading to the increase of the surface air temperature, the decrease of the surface wind speed, and the increase of the area of urban high temperature zone. The quantitative equations have been established among the surface air temperature, the carbon dioxide (CO2) concentration and the specific humidity (the water vapor content). It is predicted that the future increasing rate of the surface air temperature is 0.85℃/10yr if emission concentration of CO2 remains unchanged; if emission concentration of CO2 decreases to 75%, 50% and 25%, respectively, the surface air temperature will increase 0.65℃/10yr, 0.46℃/10yr and 0.27℃/10yr, respectively. The rise of the surface air temperature in the study area is higher than that of the global mean temperature forecasted by IPCC.

The Correlation between Density and Low-Temperature Creep Property of Asphalt

The density of asphalt was measured with the pycnometer and densitometer. Creep properties of the asphalt were investigated with the bending beam rheometer at temperatures ranging from 0 ~C to -36 ~C. The asphalt density data used to correlate with the creep properties were calculated from the regression equation of density and temperature. The asphalt sample used to determine the creep property was aged by the standard RTFOT test and the PAV test. The test results showed that the asphalt density had a linear relationship with temperature changes. The logarithm of the creep stiffness and the slope of the logarithm of the stiffness at 60 seconds all demonstrated a linear relationship with the density, and the regression coefficient of these data was around 0.99. The creep stiffness and the slope of the creep stiffness can be calculated from the asphalt density at the same temperature.

Future projection of East China Sea temperature by dynamic downscaling of the IPCC_AR4 CCSM3 model result

Future temperature distributions of the marginal Chinese seas are studied by dynamic downscaling of global CCSM3 IPCC_AR4 scenario runs. Different forcing fields from 2080-2099 Special Report on Emissions Scenarios （SRES） B1, A1, and A2 to 1980-1999 20C3M are averaged and superimposed on CORE2 and SODA2.2.4 data to force high-resolution regional future simulations using the Regional Ocean Modeling System （ROMS）. Volume transport increments in downscaling simulation support the CCSM3 result that with a weakening subtropical gyre circulation, the Kuroshio Current in the East China Sea （ECS） is possibly strengthened under the global wanning scheme. This mostly relates to local wind change, whereby the summer monsoon is strengthened and winter monsoon weakened. Future temperature fluxes and their seasonal variations are larger than in the CCSM3 result. Downscaling 100 years＇ temperature increments are comparable to the CCSM3, with a minimum in B1 scenario of 1.2-2.0~C and a maximum in A2 scenario of 2.5-4.5~C. More detailed temperature distributions are shown in the downscaling simulation. Larger increments are in the Bohai Sea and middle Yellow Sea, and smaller increments near the southeast coast of China, west coast of Korea, and southern ECS. There is a reduction of advective heat north of Taiwan Island and west of Tsushima in summer, and along the southern part of the Yellow Sea warm current in winter. There is enhancement of advective heat in the northern Yellow Sea in winter, related to the delicate temperature increment distribution. At 50 meter depth, the Yellow Sea cold water mass is destroyed. Our simulations suggest that in the formation season of the cold water mass, regional temperature is higher in the future and the water remains at the bottom until next summer. In summer, the mixed layer is deeper, making it much easier for the strengthened surface heat flux to penetrate to the bottom of this water.

Experimental study on the variation law of coal temperature during excavation in coal mines

By testing the temperature of the coal and the stress of the working surface, we got the variation law of coal temperature and coal stress during the excavation. The result shows that the activities of mining affect the coal temperature, the fluctuation of coal temperature and the coal stress is synchronous. During the smooth change of crustal stress, the coal temperature basically keeps unchanged, when the dynamic phenomenon appears, the coal temperature changes, as well the coal stress. Therefore, we can use the online coal temperature monitoring system to test the coal temperature of the working surface continuously, and it can provide basic information for forecasting coal mine power disaster before it happens.

Thick Domain Walls in Lyra Geometry with Bulk Viscosity

In this paper, we evaluate the general solutions for plane-symmetric thick domain walls in Lyra geometry in presence of bulk viscous fluid. Expressions for the energy density and pressure of domain walls are derived in both cases of uniform and time varying displacement field β. Some physical consequences of the models are also given. Finally, the geodesic equations and acceleration of the test particle are discussed.