One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must ...One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must be used. In order to overcome this issues the projection pursuit principle is introduced into water quality assessment, and projection pursuit cluster(PPC) model is developed in this study. The PPC model makes the transition from high dimension to one-dimension. In other words, based on the PPC model, multifactor problem can be converted to one factor problem. The application of PPC model can be divided into four parts: (1) to estimate projection index function Q(); (2) to find the right projection direction ; (3) to calculate projection characteristic value of the i th sample z-i, and (4) to draw comprehensive analysis on the basis of z-i. On the other hand, the empirical formula of cutoff radius R is developed, which is benefit for the model to be used in practice. Finally, a case study of water quality assessment is proposed in this paper. The results showed that the PPC model is reasonable, and it is more objective and less subjective in water quality assessment. It is a new method for multivariate problem comprehensive analysis.展开更多
目的:探究三维数字化微笑设计(three-dimensional digital smile design,3D-DSD)在前牙微笑美学修复中的应用价值。方法:选取2020年1月-2021年9月中国科学院大学深圳医院(光明)收治的拟行前牙美学修复患者120例(179颗患牙)作为研究对象...目的:探究三维数字化微笑设计(three-dimensional digital smile design,3D-DSD)在前牙微笑美学修复中的应用价值。方法:选取2020年1月-2021年9月中国科学院大学深圳医院(光明)收治的拟行前牙美学修复患者120例(179颗患牙)作为研究对象。根据随机数字表法将其分为二维组60例(88颗患牙)与三维组60例(91颗患牙)。二维组采用二维数字化微笑设计(two-dimensional digital smile design,2D-DSD)进行前牙修复,三维组采用3D-DSD进行前牙修复。比较两组修复体完成时间,修复3个月后牙龈美学效果、修复体情况。结果:三维组暂时修复体完成时间及全瓷修复体完成时间均显著短于二维组(P<0.05)。三维组龈缘最高点位置及龈缘曲线评分均显著高于二维组(P<0.05),两组近中龈乳头、远中龈乳头及根面凸度/软组织颜色和质地评分比较差异均无统计学意义(P>0.05)。三维组边缘适合性、外形及表面质地评分均显著高于二维组(P<0.05),两组表面质地及颜色匹配评分比较差异均无统计学意义(P>0.05)。结论:3D-DSD在前牙微笑美学修复中有更好的效果,可缩短修复体的制作时间,提高修复体外形准确性与边缘适合性,值得在前牙美学修复中推广。展开更多
文摘One of the difficulties frequently encountered in water quality assessment is that there are many factors and they cannot be assessed according to one factor, all the effect factors associated with water quality must be used. In order to overcome this issues the projection pursuit principle is introduced into water quality assessment, and projection pursuit cluster(PPC) model is developed in this study. The PPC model makes the transition from high dimension to one-dimension. In other words, based on the PPC model, multifactor problem can be converted to one factor problem. The application of PPC model can be divided into four parts: (1) to estimate projection index function Q(); (2) to find the right projection direction ; (3) to calculate projection characteristic value of the i th sample z-i, and (4) to draw comprehensive analysis on the basis of z-i. On the other hand, the empirical formula of cutoff radius R is developed, which is benefit for the model to be used in practice. Finally, a case study of water quality assessment is proposed in this paper. The results showed that the PPC model is reasonable, and it is more objective and less subjective in water quality assessment. It is a new method for multivariate problem comprehensive analysis.
文摘目的:探究三维数字化微笑设计(three-dimensional digital smile design,3D-DSD)在前牙微笑美学修复中的应用价值。方法:选取2020年1月-2021年9月中国科学院大学深圳医院(光明)收治的拟行前牙美学修复患者120例(179颗患牙)作为研究对象。根据随机数字表法将其分为二维组60例(88颗患牙)与三维组60例(91颗患牙)。二维组采用二维数字化微笑设计(two-dimensional digital smile design,2D-DSD)进行前牙修复,三维组采用3D-DSD进行前牙修复。比较两组修复体完成时间,修复3个月后牙龈美学效果、修复体情况。结果:三维组暂时修复体完成时间及全瓷修复体完成时间均显著短于二维组(P<0.05)。三维组龈缘最高点位置及龈缘曲线评分均显著高于二维组(P<0.05),两组近中龈乳头、远中龈乳头及根面凸度/软组织颜色和质地评分比较差异均无统计学意义(P>0.05)。三维组边缘适合性、外形及表面质地评分均显著高于二维组(P<0.05),两组表面质地及颜色匹配评分比较差异均无统计学意义(P>0.05)。结论:3D-DSD在前牙微笑美学修复中有更好的效果,可缩短修复体的制作时间,提高修复体外形准确性与边缘适合性,值得在前牙美学修复中推广。
