一种加权融合的乳腺图像增强方法

在分析人眼对图像亮度感知的基础上,针对乳腺X线片提供信息的不足,提出了一种既能改善乳腺图像边缘曝光过度,又能增强乳腺组织及钙化点的新方法．该方法首先分别采用直方图均衡化和增强高通滤波方法进行图像增强,然后再对增强后的结果进行加权融合,融合增强后的图像保持了良好的视觉效果．     

椭圆曲线密码的一种合适的对算法

在椭圆曲线密码的应用中,有些密码体制需要进行标量乘法对计算,通常在标量乘法计算时,任一整数对采用的是三元联合稀疏形式表示.在三元稀疏形式的基础上提出任一整数对的五元联合稀疏形式表示,并把这种形式用于快速Shamir算法计算标量乘法对,并证明五元联合稀疏形式比三元联合形式更有效.     

解析工程的本质 ———兼论工程与科学技术的关系

工程是指运用特定的相关的工程科学、工程技术和管理原理,优化集成整合生产要素和资源,遵循 必要的程序、设计文件、规范、规程和标准,在一定的约束条件下对自然进行改造所实施的建设（包括决策、设 计、建造、评价）活动和过程,其最终成果是一个具备预定功能的“工程实体”。工程的本质就是各种利用和改 造自然的群体性活动方式的总和。工程的基本特征有集成性、群体性、动态性和合约性。工程与科学技术的 紧密关系反映了科学技术工程一体化,反映了工程与科学技术的融合、统一及互动作用。     

内蒙古地区4种林分类型UVB屏蔽效应研究

选取内蒙古大兴安岭地区和呼和浩特市兴安落叶松、油松、樟子松和白杆4种典型针叶林,利用PC-2型太阳辐射记录仪进行UVB辐射日进程测定,以获得4种典型性针叶林的UVB屏蔽效应;对4种林分UVB屏蔽效率与枝下高、郁闭度等冠层特征因子进行相关分析.结果表明,(1)4种林分对UVB辐射均产生显著消减作用,其屏蔽效应分别为:落叶松(91.2%)、白杆(90.2%)、油松(88.9%)、樟子松(88.2%);但林分类型和时间段的不同对UVB的屏蔽效应均无显著影响.(2)UVB屏蔽效应与林分郁闭度呈正相关关系,相关系数0.635,与冠层呈负相关关系,相关系数0.966,而与林分平均树高,平均枝下高相关性不显著.     

一种基于凸壳的智能服务机器人路径规划算法

将一种基于凸壳的路径规划算法应用于体育场智能服务机器人,首先采用基于Haar特征分类器的方法确定球的坐标,采用基于颜色模型的方法确定机器人的位置及航向,并根据机器人的自身特点,将一定范围内的多个球视为一个目标点处理;然后以目标点坐标作为算法输入,采用基于凸壳的路径规划算法得到一条较优的捡球路径.该算法可以降低机器人的捡球运动代价,有效提高机器人的捡球效率.     

基于自适应特征融合的均值迁移目标跟踪

提出了一种基于自适应多特征融合的目标跟踪算法.分别利用RGB颜色和LBP纹理特征建立目标模型,通过线性加权将两类目标子特征模型代入目标相似性函数并用均值迁移算法进行目标位置优化计算.在跟踪过程中,引入S igmoid函数动态调整两类子特征权重,并利用子特征相关系数和可靠性指数对目标特征模型选择性自适应更新.实验结果表明,该算法能在跟踪场景和目标外观变化时自适应调整两种子特征权重,避免了特征失效导致的跟踪失败;特征模型选择性更新策略有效抑制了模型漂移.与单一特征和模型直接更新的跟踪方法相比,该算法在复杂跟踪环境更具有鲁棒性,能进行准确稳定的实时跟踪.     

基于音频特征和逼近信号统计特征的数字零水印算法

提出了一种基于音频特征和逼近信号统计特征的零水印算法.实验结果表明,该算法能根据音频自身的特点寻找到适合用于嵌入水印的音频帧,实现水印信息的嵌入、提取和盲检测,在不改变听觉质量的同时降低了计算量,提高了水印的鲁棒性.     

Rapid growth and sterility of growth hormone gene transgenic triploid carp

Triploid carp (100%) with 150 (3n=150) chromosomes were obtained by crossing the females of improved tetraploid hybrids (♀, 4n=200) of red crucian carp (♀)×common carp (♂) with the males of diploid yellow river carp (♂, 2n=100). The crosses yielded transgenic triploid carp (positive triploid fish, 44.2% of the progeny) and non-transgenic triploid carp (negative triploid fish). Histological examination of the gonads of 24-month-old positive triploid fish suggested they were sterile and the fish were not able to produce mature gametes during the breeding season. Morphologically, both the positive and negative triploid fish were similar. They had a spindle-shaped, laterally compressed, steel grey body with two pairs of barbells. Most of the quantifiable traits of the triploid carp were intermediate between those of the two parents. The positive and negative triploid fish were raised in the same pond for 2 years. The mean body weight of the positive triploid fish was 2.3 times higher than the negative triploid fish. The weight of the largest positive triploid fish was 2.91 times higher than that of the largest negative triploid fish. Thus, we produced fast-growing transgenic triploid carp that have a reduced ecological risk because of their inability to mate and produce progeny.     

Potential influence of water level changes on energy flows in a lake food web

Large seasonal water-level fluctuations may influence isotopic signatures of primary producers and the types and amounts of these potential food sources accessible to aquatic fauna of Poyang Lake,the largest freshwater lake in China.In this study,the isotopic signatures of primary producers and consumers were determined,stable carbon and nitrogen isotope analysis and mixing models were combined to investigate the influence of water levels on the diet and isotopic composition of Poyang Lake fish and inverteb...