对于高维度小样本数据的分类问题,高维属性的复杂性限制了分类模型预测的准确率。为了进一步提高准确率,提出了基于线性回归和属性集成的分类算法。首先,采用线性回归为每一个属性构建属性线性分类器(Attribute Linear Classifier,ALC)...对于高维度小样本数据的分类问题,高维属性的复杂性限制了分类模型预测的准确率。为了进一步提高准确率,提出了基于线性回归和属性集成的分类算法。首先,采用线性回归为每一个属性构建属性线性分类器(Attribute Linear Classifier,ALC);其次,为了避免因ALC数量过多而导致准确率下降,利用经验风险最小化策略中的经验损失值作为评估标准来优选ALC;最后,应用多数投票法来集成被筛选的ALC。采用高维度小样本的基因表达数据集进行实验,结果显示该算法具有比逻辑回归、支持向量机和随机森林算法更高的准确率。展开更多
Ontogeny and metamorphic. development of female reproductive organs in Ephedra sinica Stapf were surveyed. At the end of April, female cones began to initialize from the vegetative buds. Pollination occurred in mid-Ma...Ontogeny and metamorphic. development of female reproductive organs in Ephedra sinica Stapf were surveyed. At the end of April, female cones began to initialize from the vegetative buds. Pollination occurred in mid-May and seeds matured at the beginning of July. The ontogenetic pattern of female reproductive organs of E. sin ca is basically similar to that of E. distachya L. The foliar nature of the outer envelope of the ovule in Ephedra is corroborated. Reduction of ovule number as a tendency of speciation in the genus is substantiated by the occurrence of tri-ovulate cones coupled with comprehensive characters of the genus. The metamorphic patterns as well as the leaf nature of the outer envelope indicate that female cones of Ephedra are compound while the female reproductive units of the ovulate cone have been reduced from secondary reproductive shoots similar to those of cordaites by phylogenetic transformation, fusion and reduction. Each fertile bract together with its axillary female reproductive unit composed the Bract Scale and Seed Scale Complex of Ephedra.展开更多
Studies on acute toxicity of Cu2+,Mn2+and Zn2^to Artemianauplii(36h)and adults were carried out at15±3°C in the natural seawater where salinity is30using single-factor acute toxicity;on this basis,equi-toxic...Studies on acute toxicity of Cu2+,Mn2+and Zn2^to Artemianauplii(36h)and adults were carried out at15±3°C in the natural seawater where salinity is30using single-factor acute toxicity;on this basis,equi-toxicity test was used to evaluate the effect of joint toxicity of Cu2+,Mn2+and Zn2+to Artemia nauplii(36h)in the same conditions.Results show that Artemia has different tolerances for the three heavy metal ions when it is in different growth period,and the interaction of heavy metal ions varied with growth period,adults are more sensitive of the three heavy metals;The48h LC50of these three heavy metal to the Artemia nauplii is4.0,27.19and115.95mg/L,and to the adults is1.31,6.86and34.23mg/L;the order of toxicity of cuprum,manganese and zinc for Artemia nauplii and adults was Cu2^>Mn2+>Zn2+;the safe concentration of the three heavy metal ions(Cu2+,Mn2+and Zn2+)to Artemia nauplii(36h)and adults were0.4,2.72,11.6,0.13,0.69and3.42mg/L.The results of combined toxicity test showed that Cu-Mn,Cu-Zn and Mn-Zn were all antagonistic to the Artemia naupli.展开更多
文摘对于高维度小样本数据的分类问题,高维属性的复杂性限制了分类模型预测的准确率。为了进一步提高准确率,提出了基于线性回归和属性集成的分类算法。首先,采用线性回归为每一个属性构建属性线性分类器(Attribute Linear Classifier,ALC);其次,为了避免因ALC数量过多而导致准确率下降,利用经验风险最小化策略中的经验损失值作为评估标准来优选ALC;最后,应用多数投票法来集成被筛选的ALC。采用高维度小样本的基因表达数据集进行实验,结果显示该算法具有比逻辑回归、支持向量机和随机森林算法更高的准确率。
文摘Ontogeny and metamorphic. development of female reproductive organs in Ephedra sinica Stapf were surveyed. At the end of April, female cones began to initialize from the vegetative buds. Pollination occurred in mid-May and seeds matured at the beginning of July. The ontogenetic pattern of female reproductive organs of E. sin ca is basically similar to that of E. distachya L. The foliar nature of the outer envelope of the ovule in Ephedra is corroborated. Reduction of ovule number as a tendency of speciation in the genus is substantiated by the occurrence of tri-ovulate cones coupled with comprehensive characters of the genus. The metamorphic patterns as well as the leaf nature of the outer envelope indicate that female cones of Ephedra are compound while the female reproductive units of the ovulate cone have been reduced from secondary reproductive shoots similar to those of cordaites by phylogenetic transformation, fusion and reduction. Each fertile bract together with its axillary female reproductive unit composed the Bract Scale and Seed Scale Complex of Ephedra.
文摘Studies on acute toxicity of Cu2+,Mn2+and Zn2^to Artemianauplii(36h)and adults were carried out at15±3°C in the natural seawater where salinity is30using single-factor acute toxicity;on this basis,equi-toxicity test was used to evaluate the effect of joint toxicity of Cu2+,Mn2+and Zn2+to Artemia nauplii(36h)in the same conditions.Results show that Artemia has different tolerances for the three heavy metal ions when it is in different growth period,and the interaction of heavy metal ions varied with growth period,adults are more sensitive of the three heavy metals;The48h LC50of these three heavy metal to the Artemia nauplii is4.0,27.19and115.95mg/L,and to the adults is1.31,6.86and34.23mg/L;the order of toxicity of cuprum,manganese and zinc for Artemia nauplii and adults was Cu2^>Mn2+>Zn2+;the safe concentration of the three heavy metal ions(Cu2+,Mn2+and Zn2+)to Artemia nauplii(36h)and adults were0.4,2.72,11.6,0.13,0.69and3.42mg/L.The results of combined toxicity test showed that Cu-Mn,Cu-Zn and Mn-Zn were all antagonistic to the Artemia naupli.
