大数据时代低频采样交通轨迹数据呈指数级增长,准确、高效地对复杂路网中产生的海量低频浮动车数据进行地图匹配对出租车载客热点和路线推荐具有重要意义.基于上述考虑,提出了一种基于曲线拟合的改进算法,对缺失的轨迹数据和路网数据分别使用插值和均值化的方法进行补全,利用Geohash技术对路网和轨迹数据进行存储和搜索,充分考虑车辆速度和道路限速因素,使用轨迹点后向向量和路段向量对路候选段进行分析,设计综合评价函数得到最优匹配结果.实验结果表明,与传统垂直投影算法和曲线拟合算法进行对比,所提曲线拟合算法准确率较高,时间效率得到显著提升.

我国幅员辽阔,河流众多,洪涝灾害频发.对气象数据进行挖掘与分析,找到暗含其中的信息与知识,是构建洪涝灾害预警系统的重要研究基础.本文利用数据挖掘技术和构建知识模型设计了一个气象数据分析系统,该系统可从不同维度对采集的数据进行分析并将结果进行可视化;对来自国家气象局的相关数据进行预处理,并建立了适合于挖掘分析的气象数据库.同时,该系统还能利用内嵌的预测算法预测未来状态的数值,对突发状况起到很好的预警作用.

针对传统社区发现技术已无法有效处理大规模移动社交网络数据的问题,基于图论知识、网络性质提出山地模型,设计了滑坡算法,采用GraphX分布式图计算框架实现了并行化社区发现算法.模型首先利用模块度的聚类思想初始化山地模型并求取网络中每条边的权重,然后利用滑坡算法,迭代削弱社区间的关系,最终获得网络的社区结构.大量真实和模拟移动社交网络数据上的实验结果表明:所提算法能解决传统社区发现算法无法处理的大规模网络社区划分问题,在保证具有较高的社区识别准确率前提下,在时间性能上较现有并行社区发现算法提高140％以上,16台服务器构成的集群对于1000万个结点构成的大规模网络进行社区发现的时间不超过10 min.

如何获得更加精确的分类效果一直是机器学习领域的重要研究内容,现有大多数分类器都是针对平衡的数据集来设计的.虽然平衡的数据训练出来的分类模型能取得较好的正负样本分类正确率,但现实生活中的数据往往是不平衡的,不平衡的数据使得正样本分类正确率急剧下降,不能满足机器学习对分类效果的要求.针对这种情况,综述了当前主流不平衡分类的数据采样方法.首先,阐述了欠采样方法,包括基于聚类和基于整合的欠采样方法;其次,对过采样方法进行了总结,包括基于k近邻、基于聚类、基于半监督、基于深度神经网络和基于进化算法的过采样方法;再次,对混合采样方法进行了总结;最后,总结了不平衡分类问题研究的发展趋势.

Taking the project Digital Panzhihua supported by World Bank Loan as an example,the authors studied the construction of urban basic spatial information platform,and the sharing technology of urban public spatial information. This study ensured unified basic spatial information in all departments of professional government information,laid the foundation of strengthening of comprehensive information analysis. To establish an urban planning and management information system for demonstration,the paper researched how to combine the characteristics of own industry with department professional information system,used data service technology based on shared public spatial information platform,extended and expanded the function of department management information system. As a result,successful experience was accumulated for the popularization of digital city application system model.

Construction market and supervision of housing and urban-rural development checked and accepted Sichuan province construction market supervision and integrity integration platform On December 4,2014,which made Sichuan become the nation's first complete provincial construction market supervision and integrity integration work platform construction,and successfully passed the acceptance of provinces and cities. This platform combined information collection and release,online office,administrative examination and approval, market regulation,from main body integrity evaluation of the province's construction market into one, met the “provincial,city and county level three linkage,symbiotic system,data homologous” platform for the integration of work requirements,has a wide coverage,complete function,the characteristics of wide application. Sichuan province construction market supervision and integrity integration platform has been running in 2014. This article would work on the integration platform for the construction of the content, characteristics,structure,key technology route,the function such as technical implementation,and made a brief introduction application of the platform operation.

Based on daily precipitation at 71 meteorological stations over Northeast China observed by the China Meteorological Administration during the 1960–2011 period, the spatial and temporal distributions of climate extremes were analyzed. Twelve indices of extreme precipitation were studied. Consecutive dry days decreased and were significant at the 0.05 level, while the other precipitation indices had non-significant decreasing trends. The increase and decrease in the aspect of precipitation extreme events showed obvious spatial differences, and change patterns of these indices were not spatially clustered. Different oscillation periods were displayed very clearly in the extreme precipitation indices. Significant periodic variations with periods of a 7-year, a 14-year and a 17-year appeared in the extreme precipitation. The contribution of extreme precipitation to total precipitation decreased, and the mean trend magnitudes were influenced by the topography for the most extreme precipitation indices from 1960 to 2011. In addition, there were significant correlations between annual total precipitation and precipitation extremes, except consecutive dry days.

Based on daily and annual precipitation recorded at twenty-six meteorological stations in Qinghai Province from 1960to 2009,regression analysis,inverse distance weighted method and Mann—Kendall method were employed to analyze the spatial and temporal variability in extreme precipitation events.The results indicated that extreme precipitation days,annual maximum 1dprecipitation,annual maximum consecutive 5dprecipitation,very heavy precipitation days and daily rainfall intensity showed increasing trends in the recent 50years,and only the extreme precipitation days were significant at the 0.05level.The spatial change of precipitation extreme events in the study area showed that extreme precipitation days,annual maximum 1dprecipitation,annual maximum consecutive 5dprecipitation,very heavy precipitation days and daily rainfall intensity in Qilian Mountains had statistically increasing trends while they increased or decreased insignificantly in eastern region.In addition,it was also found that abrupt changes presented in precipitation extreme events at the 0.05level.At the same time,there were significant correlations between annual total precipitation and different precipitation indices.

Based on the data of daily maximum temperature and daily minimum temperature of 26 stations in Qinghai province from 1960 to 2009,the spatial and temporal variability of extreme temperature events was analyzed by using of regression analysis,inverse distance weighted,Mann-Kendall and wavelet analysis methods.The results showed that the occurrence of cold days and nights decreased significantly with-0.80 and-0.32d·y-1(P0.01) respectively,and the occurrence of warm days and nights increased significantly with 0.66 and 0.47d·y-1(P0.01) respectively.Both cold days(nights) and warm days(nights) existed abrupt change(P0.01).There was displayed very clearly in cold days(nights) and warm days(nights) in different periods.With climate warming in future,winter could become warmer and growth season could extend.It was necessary to take measures in agricultural production.

Based on daily temperature(maximum and minimum)and daily precipitation at 124 meteorological stations over Northwest China observed by the China Meteorological Administration during the 1960-2009 period,the variability of extreme events of temperature and precipitation over Northwest China in recent 50 years is analyzed and its extreme climatic variation in future is predicted.Eight indices of extreme temperature and six of extreme precipitation are studied.Over the 1960-2009 period,the occurrence of summer days,growing season length,hot night days and maximum temperature days have significantly increased by 2.31,2.98,1.07 and 0.45 days/decade,respectively.Over the same period,the regionally averaged occurrence of extreme ice days,consecutive frost days and minimum temperature days have significantly decreased by-2.51,-1.79 and-3.62 days/decade,respectively.The annual temperature range also exhibits a decreasing trend(-0.39 ℃/decade).With the exception of diurnal temperature range,the other indices correlate with annual mean temperature very well.Precipitation indices about annual maximum with 1-day and 5-day precipitation,consecutive dry days and averaged daily rainfall intensity have no statistically significant increasing trends while the number of heavy precipitation days and consecutive wet days decrease.At the same time,there are significant correlations between annual total precipitation and precipitation extremes except consecutive dry days.In spite of the above-mentioned main trends and correlations in most parts,the differences in spatial distribution and different climatic regions still exist significantly.

In this paper, the methods of regression analysis, inverse distance weighted and Mann-Kendall test were used to analyze the temporal and spatial variation of extreme temperature events in Gansu Province based on the daily and annual temperature data observed by 26 meteorological stations in the province during the period from 1960 to 2009. The thresholds of the extreme high temperature days and the extreme low temperature days at these stations were determined. Results indicated that the decadal trend of extreme temperature at these stations was basi- cally similar, the annual extreme high temperature was in a slight increase, but the extreme low temperature was in a slight decrease. In spite of the above-mentioned main trends in most regions, the spatial distribution differences were obvious. In addition, an obvious sharp change recent 50 years. of extreme temperature indexes occurred in Gansu Province in

The Liziwa Ditch and Huajiaopo Ditch are 2 tributary ditches in middle reaches of the Jiangjia Ditch,a famous ditch having debris flow of high frequency.These two ditches are extremely similar in conditions of drainage area,with high frequency of outbreaks of debris flow and rapid development of deposit fan.These two ditches were studied in this paper,process of movement,ceasing and accumulation of debris flow on deposit fan were observed,deposit body of debris flow with different features were sampled and analyzed,and terrain of deposit fan was measured before and after rainy season annually as well as its vertical and lateral section.By analysis of development process,planar shape,longitudinal and transverse section,accumulation rate of deposit fan in the 2 tributary ditches during 2006~2008,the following conclusions were obtained.Huajiaopo Ditch was larger in volume weight and grain size,and its accumulation was holistic and Lung Kong-shaped.Whereas Liziwa Ditch was smaller in volume weight and grain size,and debris flow overflowed on deposit fan and its accumulation was linguiform.Further development of deposit fan was completed by Lung Kong-shaped accumulation-course changing.On accumulation condition of the main channel,deposit fan in tributary ditch had mainly accretion,and extent of accretion was uniformly distributed at top and bottom of the fan.When debris flow fan developed to a certain extent,its vertical gradient was stable and smaller cross slope showed at the upstream direction of the trunk channel.