温度植被旱情指数在吉林省干旱监测中的应用

遥感技术在干旱监测中具有其他技术不可替代的优势。利用2005年8~9月的MODIS产品,获取逐日地表温度数据和逐日植被指数数据,建立了LST\|NDVI特征空间,根据此特征空间建模,计算得出温度植被干旱指数作为表征干旱的监测指标,并结合2005年土壤湿度数据对该指标进行定量验证。在此基础上利用ArcGIS软件分析了2005年8~9月吉林省干旱时空分布特征。结果表明：吉林省干旱总体分布趋势从东南到西北呈现出湿润到正常-轻旱-中旱-重旱的变化规律,体现出吉林省旱情的多样性和复杂性,8月19日、8月25日、9月8日正常和轻旱分布区域面积所占总区域面积比例分别为26.84%和59.53%、41.31%和41.73%、40.40%和32.83%,9月中旬轻旱和中旱分布最广,其比例分别为38.27%和36.26%;重旱和中旱分布区主要位于白城和松原市,轻旱区主要分布在长春、四平和辽源市,正常分布区集中在吉林、通化和白山市境内,湿润分布区主要分布在延边市。     

TM与MODIS植被供水指数反演及对比分析

为了探讨多源卫星遥感数据针对同一地区同一时刻旱情所得植被供水指数的差异,选择我国华北地区旱灾发生频率较高、影响较广的河北地区为研究区,针对近年来干旱监测应用较为广泛的Landsat TM/ETM+和EOS MODIS数据,分别进行植被供水指数的提取,并进行两者之间的对比分析,得出以下结论:① TM VSWI (Vegetation Supply Water Index) 与MODIS VSWI之间数值上存在一定的差别,变化范围在-0.51~0.20之间。其中负值主要集中在城镇、裸地及水体地表;② 在植被覆盖区,TM的平均VSWI大于MODIS的,但两者差别不大;③ 在各种植被覆盖度条件下,TM VSWI与MODIS VSWI差值的最小值、最大值和均值均表现出随着植被覆盖度的增加,其值逐渐增大的特点。该结论可以为两种遥感数据源干旱监测的差异分析及综合应用提供重要的参考依据。     

基于MODIS数据的农业干旱监测方法对比分析

利用2004年4月～6月上旬的MODIS影像数据,结合实测的土壤墒情数据,对比不同深度及不同拟合方式下土壤湿度的估算精度。另外,分别选用植被供水指数(VSWI)、基于EVI的植被供水指数(E-VSWI)、归一化多波段干旱指数(NMDI)与对应的土壤湿度数据进行回归分析,并在此基础上利用最优指数实现研究区土壤湿度的估算及旱情监测。结果表明:在华北平原中部地区冬小麦生长季节,利用MODIS数据进行土壤湿度估算的最佳深度是10cm;最佳拟合方式是线性拟合方式;植被供水指数(VSWI)在研究区整个时间序列具有最好的稳定性,可为今后大区域作物生长期的干旱监测提供一个简单方法。     

越冬期不同覆盖对土壤水分变化及黄花菜生长和产量的影响

越冬覆盖可减少冬季土壤水分的损耗,在地膜和秸秆覆盖中,以地膜覆盖保墒最好;覆盖物的不同,春季地温回升快慢不同,各处理间黄花菜生育期以地膜覆盖出现较早,秸秆覆盖出现较迟;同一时期测定的黄花菜叶长和叶宽,以地膜覆盖长势较好,秸秆覆盖长势最差。同时地膜覆盖抽薹数和落蕾数比对照多,秸秆覆盖抽薹数比对照多,而落蕾数比对照少,从而使秸秆覆盖产量比对照增产27.3%～165.9%;地膜覆盖产量因受干旱和冰雹灾害的影响不同,产量与对照比有增有减,在试验地两年里,2004年因干旱影响严重,产量比对照减产4.9%,2005年虽有干旱影响,但在春苗期,主要是受5月30日冰雹的影响,使产量比对照仅增产7.9%。黄花菜日鲜重与采摘天数呈现二次型曲线变化。     

MODIS-TVDI指数监测新疆干旱动态

针对近年频发的干旱情况不能准确及时监测评估的问题,该文以新疆为研究区域,基于温度植被干旱指数方法,利用2007年到2012年3月~8月MODIS合成产品数据获取归一化植被指数和陆地地表温度,构建LST-NDVI特征空间,得到全区的温度植被干旱指数和旱情等级空间分布图,分析了新疆干旱变化趋势,验证了温度植被干旱指数和降水因子的关系。结果表明:2007年~2012年新疆的干旱面积逐年趋于平稳,空间上表现为南疆旱情高于北疆,春季旱情高于夏季,降水量是影响温度植被干旱指数的重要因子。该研究为政府部门对新疆旱情严重地区治理提供了有效数据保证。     

HJ-1A/B卫星在干旱应急监测中的应用

利用我国环境与灾害监测小卫星(HJ-1A/B)的CCD和IRS数据,提出了针对这种新数据源的适用性应用方法,基于成熟应用的植被健康指数,对2010年3月湄公河流域发生的干旱进行应急监测,结果表明湄公河流域大部分区域农田发生干旱,中国无论从旱情发生面积和干旱严重程度上都是最为严重的。着重分析流域上游中国境内的4个水电站的水面和水位的变化信息,探讨对下游干旱的影响,得出上游大坝建设与流域下游干旱并无直接关系的结论。进一步说明了环境与灾害卫星在干旱监测应用中的可行性,将为我国乃至全球决策部门提供辅助支持信息。     

基于波段反射率日均增量的花生干旱灾情遥感评估

干旱是影响花生产量的主要气象因素之一。开展花生干旱灾情遥感评估对于产量估算、防灾减灾和保险理赔具有重要意义。当前花生旱灾遥感评估主要依赖于光谱指数变化信息,容易受不同地区生育进程干扰,限制了光谱指数方法的普适性。研究在多时相Sentinel-2遥感影像和野外实测样本的支持下,分析时序波段反射率日均增量信息与花生干旱受灾程度之间的内在联系,利用决策树、随机森林、逻辑回归等方法对花生干旱等级进行分类,并以总体精度和Kappa系数评价各种方法的精度。结果表明：单一波段的近红外反射率日均增量对花生受灾情况的指示性较强。多光谱波段组合方式对花生旱灾程度的指示性均优于单个波段,其中红波段、蓝波段、近红外光谱波段反射率日均增量组合的指示性最强,整体精度达到89.93%,Kappa系数0.847 1。与逻辑回归和决策树算法相比,随机森林算法对花生旱灾评估精度最高。在旱情等级最优时相组合分析中,利用花生生长旺盛期（7月～8月）的多波段反射率日均增量信息,灾情等级遥感识别的总体精度可达88.62%,Kappa系数为0.827 4。说明基于生长旺盛期时序多波段反射率日均增量的干旱灾情遥感评估方法能有效提取花...     

垂直干旱指数在高寒农区春旱监测中的应用研究

青海省东部农业区“十年九旱”,“春旱年年有”,对农业生产的影响非常严重,但该地区至今缺乏有效的春季干旱遥感监测方法。使用环境减灾卫星CCD数据提取青海省东部农业区农业气象观测站的垂直干旱指数(PDI),拟合其与不同深度土壤水分的关系模型,各模型的无偏相关系数均在0.7以上;其中PDI与0~20 cm土壤相对湿度关系模型(y=-489.00x+188.78)的拟合效果最好(无偏相关系数为0.7985)。该模型反演的湟源农业气象观测站固定观测地段的土壤水分时间变化序列与人工测量值的时间变化序列,在趋势变化上较为一致。2013年西宁农区的春季干旱监测中,该模型监测结果显示:发生干旱的地区主要出现在大通河谷地和湟水谷地,湟源农区的土壤旱情在整个西宁农区的土壤旱情发展中最为严重,监测结果与实际旱情分布地区一致。     

利用长时间序列Landsat分析博斯腾湖面积变化

目的 近年来博斯腾湖面积波动较大,影响当地经济发展,掌握博斯腾湖面积变化及其与气候变化的相关规律,以指导湖泊保护和可持续利用管理策略。方法 利用Landsat影像计算1988—2014年博斯腾湖面积,监测并分析湖水面积年际变化及空间变化趋势,探讨博斯腾湖流域年降水量、年均气温变化和人类活动对湖水面积的影响,并将监测结果与MODIS数据计算的2000—2014年湖水面积以及1987—2011年实测水位数据进行对比验证。结果 结果表明,以2002年为分界线,博斯腾湖面积变化分2个阶段:1)1988—2002年,湖水面积呈增加趋势,增加288.88 km²,增长了31.62%;2)2002—2014年呈减小趋势,减小281.56 km²,减少了23.42%。根据气候条件分布差异,将博斯腾湖流域分为山区和平原区,分析发现:1988—2002年,山区年降水量和气温上升,与湖水面积呈显著正相关;2002年后,山区年降水量相对下降,平原区气温升高,人类活动用水量增加。结论 湖水面积变化受流域气候与人类活动共同作用,1988—2002年主要受山区气候影响,2002年后湖水面积缩小可能是气温升高和人类活动用水量增加导致。     

中亚五国主要湖泊水面变化特征及关键影响因素分析

中亚五国位于水资源严重不足的内陆地区,湖泊是该地区生态系统的主要支撑。由于以往的相关研究缺乏年内和年际长时间序列的信息支持,很难全面地认识中亚五国主要湖泊变化特征。以2001～2016年MODIS 8d的反射率产品作为数据源,利用归一化水体指数(Normalized Difference Water Index,NDWI)的方法提取水体面积,分析近15 a来中亚9个主要湖泊的年内和年际间水面变化特征及关键影响因素。结果表明:①中亚五国湖泊水面变化受人为干扰和气候变化双重影响,平原尾闾和高山封闭性湖泊年内和年际时间序列呈现不同的变化趋势和波动特征;②平原尾闾湖中的南、北咸海变化最为明显,南咸海近15 a水面面积呈明显的减少趋势,减少面积超过70%,而北咸海则随降水变化呈现波动的特征;③中亚主要湖泊的总面积呈减少的趋势,15 a来面积缩减了23.51%,南咸海是统计的所有湖泊面积减少的主要贡献者,除南咸海外,其他湖泊水面面积呈增长的趋势。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。