Affine invariant shape recognition with particle swarmoptimization algorithm     

MAO Yu xing  HAN Bei tao  FENG Lian  WANG Hao  XU Shao zhi  HAO Yuan yang 《保鲜与加工》2010,(3):65-71

Focusing on the problem that affine transformation will exist among the contour images due to variation of the viewpoints, a new approach to extract affine invariant features and matching strategy is proposed for shape recognition. First, the centroid distance and azimuth angle of each boundary point are computed. Then, with a prior defined angle interval, all the points in the neighbor region of the sample point are considered to calculate the average distance for eliminating noise. After that, the centroid distance ratios(CDRs) of any two contour points with angle difference of 180° are achieved as the representation of the shape, which would be invariant to affine transformation. Since the angles of contour points changed non linearly among affine related images, the CDRs should be resampled to build corresponding relationship. It could be regarded as an optimization problem of path planning. In our method, a PSO based path planning model is presented to address this problem. The experimental results demonstrate the efficiency of the proposed method in shape recognition with translation, scaling, rotation, distortion and noise interference.  相似文献   

Dynamic characteristics of CVT hydraulic system in speed ratio changing     

YANG Yang  WANG Xiao ping  QIN Da tong  TANG Tao feng 《保鲜与加工》2010,(4):9-13

Aiming at the hydraulic system of CVT (Continuously Variable Transmission), the transfer function of hydraulic system of CVT and the dynamic simulation model of this system based on AMESIM are built, and the characteristics of speed ratio response is simulated and calculated. The influences of spring constant, damping coefficient and mass of moving part on rising time, setting time and overshoot are analyzed. The result shows that the dynamic simulation model of this system is reasonable and will provide a basis and method for the optimization of CVT hydraulic system’s dynamic characteristics in the future.  相似文献   

不同激素配比对重瓣矮牵牛组织培养的影响     

宗宪春  宗灿华  刘静  司徒琳莉  任如意  佟亚辉 《安徽农业科学》2010,38(17):8877-8878,9102

[目的]研究不同激素配比对重瓣矮牵牛组织培养的影响。[方法]以重瓣矮牵牛叶片为外植体,研究不同激素配比对其愈伤组织、不定芽诱导和不定芽生根的影响。[结果]愈伤组织及不定芽的诱导以MS＋6-BA 2.0 mg/L＋NAA 0.2 mg/L最佳,不定芽生根以1/2 MS＋NAA 0.1 mg/L或1/2MS＋IBA 0.1 mg/L最佳,产生的根较粗,数量较多。[结论]该研究结果为重瓣矮牵牛的快速繁殖、种质资源的保存和遗传转化建立了基础。  相似文献   

流域特征及景观格局对泥沙输移比的影响研究综述     

王然  岳德鹏  王计平 《安徽农业科学》2010,38(19):10141-10143

泥沙输移比是目前预测流域产沙量的一种较实用的方法,它的确定受到很多因素的影响,其中流域特征和流域的景观格局是影响泥沙输移比的重要因子。从流域特征和景观格局两大方面对泥沙输移比研究进行综述,以期为我国开展土壤侵蚀及泥沙输移研究提供参考。  相似文献   

Successful drug development despite adverse preclinical findings part 1: processes to address issues and most important findings     

Ettlin RA  Kuroda J  Plassmann S  Prentice DE 《Journal of toxicologic pathology》2010,23(4):189-211

Unexpected adverse preclinical findings (APFs) are not infrequently encountered during drug development. Such APFs can be functional disturbances such as QT prolongation, morphological toxicity or carcinogenicity. The latter is of particular concern in conjunction with equivocal genotoxicity results. The toxicologic pathologist plays an important role in recognizing these effects, in helping to characterize them, to evaluate their risk for man, and in proposing measures to mitigate the risk particularly in early clinical trials. A careful scientific evaluation is crucial while termination of the development of a potentially useful drug must be avoided. This first part of the review discusses processes to address unexpected APFs and provides an overview over typical APFs in particular classes of drugs. If the mode of action (MoA) by which a drug candidate produces an APF is known, this supports evaluation of its relevance for humans. Tailor-made mechanistic studies, when needed, must be planned carefully to test one or several hypotheses regarding the potential MoA and to provide further data for risk evaluation. Safety considerations are based on exposure at no-observed-adverse-effect levels (NOAEL) of the most sensitive and relevant animal species and guide dose escalation in clinical trials. The availability of early markers of toxicity for monitoring of humans adds further safety to clinical studies. Risk evaluation is concluded by a weight of evidence analysis (WoE) with an array of parameters including drug use, medical need and alternatives on the market. In the second part of this review relevant examples of APFs will be discussed in more detail.  相似文献   

西双版纳热带植物园主要种植园区太阳辐射特征比较研究     

张一平  赵俊斌  宋清海  梁志 《北京林业大学学报》2010,32(4):136-143

利用2008—2009年间太阳辐射观测资料,分析了西双版纳热带植物园主要种植园区太阳辐射的变化特征,得出其变化及能量分配的相关规律。研究结果表明:在各植物园区,太阳辐射各分量均呈现单峰性变化,中午出现最大值;在具有高大树木、遮蔽较大的种植园区,太阳辐射各分量日总量与旷地的比值较小,在仅有低矮树木的百果园,其比值较大;西双版纳热带植物园植物种植园区,其形成的植物群落结构对太阳辐射的作用已经与原生林或次生林相当,具有明显林下辐射的特征,为植物园进行植物的迁地保护提供了较为原始的森林环境,减少植物的人为驯化,最大程度地保证原物种的遗传特征;不同园区辐射特征对植物迁地保护种植区域的选择提供了依据。  相似文献   

新广州站三向张弦梁结构优化设计     

蔡建国  涂展麒  冯健 《湖南农业大学学报(自然科学版)》2010,37(5):12-17

基于运用APDL语言对新广州站工程三向张弦梁结构建立的参数化模型,利用一阶优化方法,对初始结构进行全构件截面和形状参数的综合优化.并在矢高和垂度确定的情况下,分别采用分级优化和综合优化分析了构件截面的合理取值.分析结果表明：矢高和垂度是三向张弦梁结构设计中极为重要的设计参数,新广州站三向张弦梁结构的最佳矢高为9.189 m,其垂跨比应不小于0.034,下弦垂度和上弦矢高的经济比值为0.22~0.23.上弦拱构件在结构中占的比重较大,可以通过减小拱截面的壁厚来降低结构的用钢量.并通过综合优化得到新广州站三向张弦梁的最佳梁弦刚度比为1.23×10-4  相似文献   

不同浓度硼砂溶液对日光温室油桃坐果率的影响   总被引：4，自引：0，他引：4  

马建华  郭永清  宝秋利 《现代农业科技》2010,(7):122-122

日光温室栽培油桃普遍存在果实坐果率低、果个小、着色差等问题。微量元素硼能促进碳水化合物的合成和运转、刺激花粉粒的萌发和花粉管的伸长,提高坐果率。选用0.1%、0.3%、0.5%等3种不同浓度的硼砂溶液,在油桃初花期喷施叶片。结果表明,用硼砂溶液处理过的油桃坐果率都有所增加,浓度为0.1%的硼砂溶液坐果率最高,较喷清水提高了6.37个百分点。  相似文献   

毛竹雨雪冰冻灾害主要影响因子的回归分析     

高培军  桂仁意  黄坚钦  李国栋  应叶青  方伟 《福建林学院学报》2010,30(2)

应用逐步引入剔除法对毛竹受雨雪冰冻灾害程度的海拔、坡度、坡位、坡向、土壤深度、经营管理、竹林密度等因子与折断率、倒伏率、受损率分别进行多元线性回归分析,经检验F>F0.01,P<0.01,偏回归系数(bi)均为显著或极显著,说明回归方程均有极显著意义。通过标准偏回归系数(b′i)检验自变量的主次关系,表明影响折断率的主导因子及各因子的主次关系为海拔>土壤深度>坡位>坡度,海拔、坡度与折断率呈正相关,坡位、土壤深度与折断率呈负相关;影响倒伏率的主导因子及各因子的主次关系为竹林密度>坡度>经营管理>土壤深度,坡度、经营管理与倒伏率呈正相关,竹林密度、土壤深度与倒伏率呈负相关;影响受损率的主导因子及各因子的主次关系为土壤深度>坡度>海拔>竹林密度>经营管理,海拔、坡度、经营管理与受损率呈正相关,竹林密度、土壤深度与受损率呈负相关。说明回归模型可用于毛竹折断率、倒伏率和受损率预测。  相似文献   

蔬菜无土栽培基质初步筛选研究   总被引：6，自引：0，他引：6  

焦永刚  石琳琪  董灵迪  郭敬华  曹彩霞 《河北农业科学》2010,14(9):26-28

以草炭、蛭石、炉渣、废菇料和粉碎后的玉米秸秆为原料,按不同材料种类及比例混合制成8种蔬菜无土栽培复合基质,测定并比较了8种复合基质的理化性质,初步筛选出适宜蔬菜栽培的优良基质。结果表明：8种基质的容重、pH值和总孔隙度均在蔬菜栽培的适宜范围内;大小孔隙比、基质电导率及成本上各有优劣。通过综合考量,初步优选出的无土栽培基质为基质Ⅳ（V棉籽皮∶V炉渣=1∶1）、基质Ⅵ（V棉籽皮∶V蛭石=1∶1）和基质Ⅶ（V玉米秸秆∶V棉籽皮∶V蛭石=1∶1∶2）。  相似文献