生态监测时空信息微服务:架构、技术与应用——以南岭国家站为例

随着物联网、大数据等新一代信息技术和生态系统与生物多样性监测领域的深度融合,持续汇聚的海量、多源异构、多模态时空大数据资源的高效管理与智能应用具有重要意义。以南岭森林生态系统国家野外科学观测研究站(简称“南岭国家站”)积累的时空监测大数据为研究对象,设计了面向森林生态系统与生物多样性监测的时空信息微服务架构,阐明了微服务划分与封装、数据抽取方法等关键技术,研发了南岭国家站生态系统与生物多样性监测时空数据管理平台,有效管理和分析了南岭国家站的时空大数据资源。测试与应用分析表明,森林生态系统与生物多样性监测时空信息微服务架构能够满足生态监测大数据高效管理的核心应用需求,提升了生态监测时空数据资源的科学管理效率,可为森林生态系统与生物多样性监测时空大数据管理提供有力的新工具。

国内外兽药监管信息化建设现状及趋势

兽药监管信息化是提高兽药监管效率、保障兽药产品质量的有效途径。以美国、加拿大和欧盟为例,重点回顾了国外兽药监管信息化主要进展。针对兽药产销全过程重要环节,归纳总结我国兽药产销全过程的审批、生产、流通、监督检验和追溯环节的信息化建设现状,以及我国兽药网络信息共享与应用取得的最新成效。对比分析国内外兽药产销全过程重要环节信息化建设差异,明晰了我国兽药监管信息化存在的主要问题,提出了我国兽药监管信息化发展方向及应对措施,为提高我国兽药监管信息化水平、实现兽药全过程追溯提供参考。

Automatic image segmentation method for cotton leaves with disease under natural environment

In order to improve the image segmentation performance of cotton leaves in natural environment, an automatic segmentation model of diseased leaf with active gradient and local information is proposed. Firstly, a segmented monotone decreasing edge composite function is proposed to accelerate the evolution of the level set curve in the gradient smooth region. Secondly, canny edge detection operator gradient is introduced into the model as the global information. In the process of the evolution of the level set function, the guidance information of the energy function is used to guide the curve evolution according to the local information of the image, and the smooth contour curve is obtained. And the main direction of the evolution of the level set curve is controlled according to the global gradient information, which effectively overcomes the local minima in the process of the evolution of the level set function. Finally, the Heaviside function is introduced into the energy function to smooth the contours of the motion and to increase the penalty function Φ(x) to calibrate the deviation of the level set function so that the level set is smooth and closed. The results showed that the model of cotton leaf edge profile curve could be obtained in the model of cotton leaf covered by bare soil, straw mulching and plastic film mulching, and the ideal edge of the ROI could be realized when the light was not uniform. In the complex background, the model can segment the leaves of the cotton with uneven illumination, shadow and weed background, and it is better to realize the ideal extraction of the edge of the blade. Compared with the Geodesic Active Contour(GAC) algorithm, Chan-Vese(C-V) algorithm and Local Binary Fitting(LBF) algorithm, it is found that the model has the advantages of segmentation accuracy and running time when processing seven kinds of cotton disease leaves images, including uneven lighting, leaf disease spot blur, adhesive diseased leaf, shadow, complex background, unclear diseased leaf edges, and staggered condition. This model can not only conduct image segmentation of cotton leaves under natural conditions, but also provide technical support for the accurate identification and diagnosis of cotton diseases.

Spatial-Temporal Changes in Grain Production, Consumption and Driving Mechanism in China

The spatial-temporal patterns of grain production and consumption have an important influence on the effective national grain supply on condition of tight balance in the total grain amount in China. In this paper, we analyze the spatial-temporal pattems of grain production, consumption and the driving mechanism for their evolution processes in China. The results indicate that both gravity centers of grain production and consumption in China moved toward the northern and eastern regions, almost in the same direction. The coordination of grain production and consumption increased slightly from 1995 to 2007 but decreased from 2000 to 2007. There is a spatial difference between the major districts of output increase and the strong growth potential in grain consumption, which indicates an increasing difficulty in improving the regional coordination of grain production and consumption. The movement of the gravity center of grain production is significantly correlated with regional differences in grain production policy, different economic development models, and spatial disparity of land and water resource use. For grain consumption, the main driving factors include rapid urbanization, the upgrade of food consumption structure, and distribution of food industries.

Impact of climate change on maize yield in China from 1979 to 2016

Climate change severely impacts agricultural production, which jeopardizes food security. China is the second largest maize producer in the world and also the largest consumer of maize. Analyzing the impact of climate change on maize yields can provide effective guidance to national and international economics and politics. Panel models are unable to determine the group-wise heteroscedasticity, cross-sectional correlation and autocorrelation of datasets, therefore we adopted the feasible generalized least square(FGLS) model to evaluate the impact of climate change on maize yields in China from 1979–2016 and got the following results:(1) During the 1979–2016 period, increases in temperature negatively impacted the maize yield of China. For every 1℃ increase in temperature, the maize yield was reduced by 5.19 kg 667 m^–2(1.7%). Precipitation increased only marginally during this time, and therefore its impact on the maize yield was negligible. For every 1 mm increase in precipitation, the maize yield increased by an insignificant amount of 0.043 kg 667 m^–2(0.014%).(2) The impacts of climate change on maize yield differ spatially, with more significant impacts experienced in southern China. In this region, a 1℃ increase in temperature resulted in a 7.49 kg 667 m^–2 decrease in the maize yield, while the impact of temperature on the maize yield in northern China was insignificant. For every 1 mm increase in precipitation, the maize yield increased by 0.013 kg 667 m^–2 in southern China and 0.066 kg 667 m^–2 in northern China.(3) The resilience of the maize crop to climate change is strong. The marginal effect of temperature in both southern and northern China during the 1990–2016 period was smaller than that for the 1979–2016 period.

Price Transmission in China's Swine Industry with an Application of MCM

The paper studies the relationship, adjustment ability, path, efficiency and intensity of price transmission in the swine industry chain in China, which consists of the prices of corn, compound feed for fattening pig, piglet, pig and pork. Monthly prices covering a period of 18 yr （1994-2011） are analyzed using a Market-Chain Cooperated Model （MCM）. The empirical results show that there exists a stable long-term cointegration and short-term dynamic relationship in the price system. First, the adjustment speed of each price series is very slow and the transmission path is top-down and one-way significantly. Second, the price from upstream to downstream lags about 2 mort, while there is no lag in price transmission from midstream to downstream. Third, in terms of price transmission intensity, the price of pig impacted greatly on pork price, not only in the current period but also through the whole period. Besides, the price of corn has the largest lagged effects on pork price. According to the above empirical results, we suggest that government should strengthen monitoring and early warning of the swine industry chain, especially the upstream and midstream, attach great importance to the timely adjustment of feed prices and perfect the measures of price subsidy.

基于土壤重金属镉污染评价的“湘莲+”种植区划

“湘莲+”产业是湖南省湘潭县重点支持的农业特色优势产业,是实现重金属污染耕地种植结构调整的重要途径。为因地制宜发展“湘莲+”产业,采用普通Kriging法对基于地累积指数的土壤重金属镉(Cd)的污染风险进行空间插值,结合“湘莲+”产业发展需求,开展多级适宜区划分。结果表明,采用多尺度套合模型优化变异函数的普通Kriging法能有效提高土壤重金属污染风险的插值精度;种植适宜区可划分为三级,一级和二级是“湘莲+”产业发展的首选区域,一级区占总面积95.41%,宜侧重农旅融合,二级区占4.28%,宜发展“种养加”结合,污染风险较高且与最近主干道距离相对较远的三级区仅占0.31%,宜优化产业结构。本研究可为“湘莲+”产业定量区划提供有力方法和数据支撑。

固相反应法制备CaO-B2O3-SiO2介电陶瓷及性能研究

Ca(OH)2、H_3BO3、SiO_2作为初始原料应用固相反应法在低烧结温度下制备CaO-B_2O_3-SiO_2(CBS)介电陶瓷材料。研究了不同烧结温度和B_2O_3含量对陶瓷的致密性、介电和机械性能的影响。X射线衍射(XRD)分析表明,在875℃至975℃的温度范围内,存在主要的结晶相为β-Ca SiO_3和少量SiO_2相。结果表明,最佳烧结温度为950℃,B_2O_3含量的增加会使得烧结温度区间变窄,发生"硼反常"现象,并且致密度、介电性能和机械性能也会随之先减小后增大。并且过量的B_2O_3不利于主晶相β-Ca SiO_3的析出。当B_2O_3含量为25mol%时,在950℃烧结的试样具有最好的抗弯强度:σf=319 MPa。当B_2O_3含量为5mol%时,在950℃烧结的试样具有最好的致密性和介电性能:密度为2. 6869 g/cm^3,εr=6. 12,tanδ=7. 4×10^(-4),ρv=6. 64×10^(-4)Ω·cm (1 MHz)。

考虑折返行为和响应时间的大型邮轮人员疏散仿真

为研究乘客的折返行为和响应时间对大型邮轮人员疏散过程的影响,采用AnyLogic社会力模型仿真平台建立一艘大型邮轮人员疏散模型,分析不同折返比例下折返行为对该艘邮轮乘客疏散时间、疏散流率、拥挤区域和拥挤持续时间的影响;在此基础上,考虑了乘客响应时间对邮轮疏散进程的影响。仿真结果表明:乘客的折返行为对邮轮疏散进程有显著的减缓作用,会增加楼梯的拥挤持续时间;乘客的响应时间对邮轮疏散进程的影响较为复杂,折返比例在20%及以下时,乘客存在响应时间会减缓邮轮疏散进程,折返比例在30%及以上时,乘客存在响应时间可一定程度上加快邮轮疏散进程。该研究对大型邮轮人员疏散方案的制定和优化具有一定的指导意义。