Development of a new index for automated mapping of ratoon rice areas using time-series normalized difference vegetation index imagery

Over recent decades, the global demand for food has continued to grow, owing to population growth and the loss of arable land. Rice ratooning offers new opportunities for increasing rice production and has received renewed interest because of the minimal additional labor input required for its adoption. Regular, regional-scale monitoring of the spatial patterns of both traditional and ratoon rice cropping systems provides essential information for agricultural resource management and food security studies. However, the similar phenological characteristics of traditional double rice and ratoon rice cropping systems make it challenging to accurately classify these cropping practices based on satellite observations alone. In this study, we first proposed an improved phenology-based rice cropping area detection algorithm using moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) imagery. A new index, ratoon rice index, was then developed to automatically delineate ratoon rice cropping areas with the aid of a base map of rice in Hubei Province, China. The accuracy assessment using ground truth data showed that our approach could map both traditional and ratoon rice cropping areas with high user accuracy (91.25% and 91.43%, respectively). The MODIS-retrieved rice cropping areas were validated using annual agricultural census data, and coefficient of determination (R²) values of 0.60 and 0.41 were recorded for traditional and ratoon rice cropping systems, respectively. The total area of ratoon rice was estimated to be 1 283.6 km², 5.0% of the total rice cropping area, in Hubei Province in 2016. These demonstrated the feasibility of extracting the spatial patterns of both traditional and ratoon rice cropping systems solely from time-series NDVI and field survey data and strides made in facilitating the timely and routine monitoring of traditional and ratoon rice distribution at subnational level. Given sufficient historical satellite and phenology records, the proposed algorithm had the potential to enhance rice cropping area mapping efforts across a broad temporal scale (e.g., from the 1980s to the present).     

改进加权FCM用于裂纹蛋2D图像分割的研究

解决裂纹鸡蛋图像灰度直方图目标与背景区域分布模糊、图像分割效果差的问题.通过将包含空间信息的二维直方图和改进特征加权FCM算法有机结合,迭代寻求最佳聚类有效性函数和加权矩阵,实现鸡蛋图像缺陷分割.同时,对经典FCM和改进特征加权FCM算法的性能进行了分析比较.结果表明:提出的算法更接近于真实聚类中心,目标函数值亦得到改善;二维直方图的改进特征加权模糊聚类算法更好地提取了裂纹鸡蛋图像的细节信息,图像分割效果好.     

一种监测喷雾装备速度的方法与实现

基于最短距离法的原则,设计了一种时间匹配算法用来监测喷雾装备前进的速度.首先,在运动路径中设置匹配点;然后,利用GPS接收机静态采集的匹配点位置信息匹配GPS接收机动态采集的轨迹信息,从而可以得到装有GPS接收机的运动装置在运动过程中经过匹配点的时间;最后,通过实验使用GPS接收机和机器人来修正这一匹配算法,提高了匹配精度.     

基于自适应邻域Harris算子的三维对象检索方法

针对三维对象检索过程中在对象旋转、灰度改变等复杂情况下检索精度不高的问题,提出一种三维对象检索方法。将Harris算子扩展运用到三维对象,自适应地确定顶点的邻域大小,然后根据Harris函数响应值选取兴趣点。利用兴趣点构建三维对象具有全局形状特征的距离直方图,将距离直方图作为三维形状的描述符进行检索。实验结果验证了算法的有效性,提高了检索的查全率和查准率。     

主题配对法在卫浴产品设计中的应用

为了满足用户快速获得多样化产品的需求，解决卫浴产品设计中设计方案大量生成问题，应用主题配对的研究方法，探讨了主题配对模型与卫浴产品设计，并以花洒设计为例，构建了基于主题配对模型和计算机辅助设计花洒三维形态设计系统软件.在生产实践中，该系统实现了卫浴产品设计的快速产业化，提高了卫浴产品开发设计效率.     

自行设计的装载机性能计算软件及其应用

目前,装载机广泛采用液力机械式传动,柴油机与液力变矩器的组合可看作一种新的动力源,具有与柴油机不同的性能特性。通过图形用户界面(GUI),自行开发一款专门用于装载机性能仿真的软件,该软件弥补了国内同类型软件无法进行工作循环计算的不足,并以ZL50型装载机的一个工作循环为例进行了动力性和经济性的仿真分析。仿真结果表明,此软件能够方便地进行装载机动力性及经济性能的仿真分析。     

东北平原棕壤土区合理耕层耕作模式与配套机具研究

目前,土地沙漠化面积增大,传统耕作机械田间作业频繁,增加了土壤坚实度,使土壤容重增加,造成了土壤的板结,犁底层加厚上移,影响作物产量、制约了农业生产的可持续发展。针对东北平原棕壤土区辽宁省铁岭县的实际情况,结合联合整地、深松、深松联合整地及免耕播种4种耕作模式,与当地农作物种植合作社合作,对4种模式的土壤理化性质进行测试。在距地表5、10、15cm土壤深度时,深松模式土壤温度高于联合耕整地模式1.6、1.5、1.1℃;免耕播种比联合耕整地模式的土壤温度分别高了2.8、2.2、1.9℃。土壤含水率方面,免耕播种含水率最高,在垄台、向阳面、向阴面分别比联合耕整地模式高6.9%、12.2%、15.2%;在土壤容重与土壤紧实度方面,深松模式在深度10~30cm范围内土壤容重低于未深松模式0.3g/cm3。根据土壤理化特性,运用线性规划方法对现有配套机具进行优化配备,并对配备后进行效益分析,得出深松覆盖模式的收益最高,达到1.29万元/hm~2;其次是免耕播种模式,达到1.25万元/hm~2;深松联合整地模式与联合整地模式分别为0.90万元/hm~2和0.74万元/hm~2。同时,提出了一种适合当地土壤性质的耕作模式与合理配套机具。     

New versus old broiler housing technology: Which leads to greater profit?

The method of matching samples was used to compare the costs and returns associated with broiler housing technology using Agricultural Resource Management Survey data for 2006 and 2011. Farms with housing that included tunnel ventilation and evaporative cooling cells (new technology) were compared with farms with housing that did not include this technology (old technology). Gross farm income, total variable expenses, and total fixed expenses were higher for the new technology farms for both years. New technology farms had greater income over variable expenses and net cash farm income in both years.     

生物图像阈值分割方法的研究

阈值法是最基本的图像分割方法之一,被应用于很多领域,特别是在图像相对简单的生物图像处理方面得到了广泛使用.本文对现有的各种图像阈值分割方法进行综述,重点介绍了基于图像灰度直方图的阈值分割方法.     

农户新一轮退耕还林的福利效应研究——基于陕南退耕还林区的实证分析

文中利用陕南退耕还林区实际调研数据,依据森的福利理论设计福利度量指标体系,采用模糊综合评价法测算农户福利水平,并探讨了退耕还林对农户的福利效应。结果表明:1)退耕户与非退耕户福利存在差异,且退耕户的福利总模糊指数大于非退耕户。2)退耕还林工程使得农户的总福利、主观福利和客观福利均有所提高,但退耕还林工程对农户主观福利的提高程度远远小于客观福利。3)退耕规模影响农户福利,提高退耕规模有助于提高农户总福利水平和客观福利水平,但对主观福利水平的促进作用仅在福利水平处于中间阶层及偏上农户身上发挥作用。新一轮退耕还林的扶贫效果明显,政府应更多关注退耕还林农户的福利变化状况,出台措施提高农户主观福利,并针对不同类型农户采取差异化措施。