半色调图像纹理特征提取方法

提出基于局部二值化模式和像素相关算子的半色调图像纹理特征提取方法,以实现误差分散类半色调图像的分类。该方法是将误差分散类图像先进行局部二值化模式变换,再以任一像素点为中心,取适当的距离提取八个方向的像素相关值作为图像的特征向量,最后将提取的特征通过BP神经网络进行分类。实验结果表明,提出的算法适用于二值图像的特征提取,能够降低局部二值模式的特征维数,提高时间效率和空间利用率;相对灰度共生矩阵算法提出的算法在计算复杂度、识别精度等性能方面都有所改善。     

非定常Navier-Stokes方程有限元算子分裂算法

在连续解的正则性假设条件下,基于亚格子稳定模型和算子分裂方法提出了非定常不可压Navier-Stokes方程的有限元算子分裂算法.其主要思想是:利用算子分裂方法把非线性项和不可压缩项分开,首先求解一个线性化的Burger's问题得到有限元解■,然后再求解一个Stokes问题得到解u■.证明了速度的误差估计关于时间是一阶收敛的,并给出数值实验验证了理论的正确性.     

一类新的含A-单调映像的完全广义集值强非线性混合隐拟变分包含

在Hilbert空间中引入和研究了一类新的包含A-单调映像的完全广义集值强非线性混合隐拟变分包含.通过应用A-单调映像的预解算子技巧,构造了一个新的迭代算法来逼近此类变分包含的解.讨论了由此算法产生的迭代序列的收敛分析.     

湿地土壤质量退化的模糊综合评价

Wetland soil quality degradation caused by large-scale agricultural reclamation on the Sanjiang Plain of Northeast China has been widely reported. A relative soil quality evaluation (RSQE) model and a projection pursuit evaluation (PPE) model based on real-coded accelerating genetic algorithm were introduced to evaluate quality variations in top layers of the main wetland soils on the Sanjiang Plain in 1999 and 2003, respectively. As soil quality degradation boundaries were vague, this study established two fuzzy synthetic evaluation (FSE) models based on the original data and criteria used in the RSQE and PPE models. The outputs of the two FSE models were obtained by choosing two fuzzy composite operators M (∧,∨) and M (?,⊕). Statistical analysis showed that the results of the FSE, RSQE, and PPE models were correlated. In particular, outputs of the FSE model using M (?,⊕) were significantly correlated with those of the RSQE model with r = 0.989 at P < 0.01. Compared with RSQE and PPE models, the FSE model may be more objective in showing soil quality variations and was closer to the natural situation, showing the feasibility and applicability of the FSE model in evaluating soil quality degradation. However, the choice of composite operator was of critical importance. The study of wetland soil quality degradation on the Sanjiang Plain was of scientific and practical significance for protection and management of soils and for sustainable development of agriculture in this area in the future.     

基于角色的访问控制在新疆农科院WEB网站中的应用研究

为了更好地对科研院所网站信息进行维护管理,让不同单位和部门的信息管理人员实现信息的有效管理和即时发布,将基于角色的访问控制方式应用到网站后台用户管理中。通过对网站管理人员的权限需求分析,建立网站用户基于角色的访问控制模型,以此设计网站后台用户管理子系统。解决了不同权限管理者对网站管理的需求,实现了权限管理者对自己本单位网站信息的操作控制管理。满足了不同层次管理人员权限分配的要求。     

Potential dermal pesticide exposure affected by greenhouse spray application technique

BACKGROUND: Operator safety is still one of the main problems concerning greenhouse spray applications in South European horticulture. The main objective of this study was to compare potential dermal exposure (PDE) between traditional handheld spray application techniques (i.e. a standard spray gun walking forwards, a spray lance walking forwards and backwards) and novel spray application techniques with spray booms (i.e. a trolley, the Fumimatic and the Fumicar). RESULTS: PDE varied from 19.7 mL h^?1 for the Fumimatic to 460 mL h^?1 for the spray lance walking forwards. Walking backwards reduced PDE by a factor 7. With the trolley, Fumimatic and Fumicar, PDE was respectively 20, 60 and 8 times lower than with the standard spray gun. With the spray lance, PDE was about 2.5 times higher than with the spray gun. Pesticide distribution over the operator's body was non‐uniform and correlated strongly with the application technique. With the traditional techniques, exposure to the legs and feet represents 60–80% of the total exposure. CONCLUSIONS: Novel spray application techniques using spray booms greatly decrease operator exposure because the operator is not walking directly into the spray cloud and the sprayed crop, and because of their higher capacity. Depending on the type of spray application, different parts of the body need to be protected most. Copyright © 2009 Society of Chemical Industry     

基于SNS的高校图书馆服务新突破

文章介绍了SNS的理论根源及内涵,然后分析了高校图书馆服务中使用SNS的现状,提出了在目前的服务基础上,图书馆利用SNS网站的优势,可以在参考咨询、读者教育、馆藏资源建设和学科建设方面提供更好的服务。     

基于改进的双极Slope One算法的农业信息推荐模型研究

为了在海量信息中为用户提供有价值的信息,个性化在线推荐系统是农业信息化综合服务平台的重要组成部分。Slope One算法因简单高效被许多在线推荐系统使用。对Slope One算法进行研究,并结合农业信息化综合服务平台的特点,提出了农业信息推荐模型。该模型按资源类别把用户评分矩阵划分为评分子矩阵,在此基础上采用杰卡德统一算子距离相似度算法建立用户类别近邻用户,采用改进的双极Slope One算法和Item user average算法相结合的方式对未访问资源进行评分预测,有效降低计算量,并提高了评分预测精度,既适合稠密数据集,又适合稀疏数据集。     

植保信息交流网动态网站的建立及运行

基于植保信息交流网(http://www.ppien.com)的构建,介绍了动态网站实现的基本方法,探索了使用ASP脚本语言创建动态网站,进行科技交流和推广的新路子,对植保信息交流网的几个动态栏目的功能及运行效果进行了概述。     

基于模糊理论的城市交通生态环境综合评价模型研究

根据城市交通生态环境系统的复杂性,对影响城市交通生态环境质量的指标因素进行提炼,确定了指标因素的隶属度函数,建立了基于不同模糊算子的城市交通生态环境质量多阶模糊综合评价模型.针对合肥市4条道路的交通环境质量监测数据,利用建立的评价模型,采用不同的模糊算子进行分析优化.此模型也可用于其他城市交通生态环境质量的评价.