共查询到20条相似文献，搜索用时 93 毫秒
1.
随机森林是一种优秀的分类算法,然而随机森林算法不能有效的判断冗余属性,因此影响了在含有冗余属性的数据集上的分类效果。针对这一问题,本文提出了一种基于局部线性嵌入的随机森林算法。该算法利用局部线性嵌入算法对冗余属性数据集进行降维,然后利用随机森林算法进行分类学习。在UCI标准数据集上的仿真实验说明,本文算法是一种优秀的含冗余属性数据集分类算法。 相似文献
2.
3.
4.
5.
本文提出了一种免疫克隆选择算法与模糊C-均值聚类算法相结合的混合聚类算法。首先用克隆选择算法对模糊聚类中心的个数和聚类中心的选取进行指导,然后进行聚类,是一种有监督学习和无监督学习结合的一种算法,将该算法用于汽轮机的故障诊断中,诊断结果表明,该方法能够正确地诊断出存在的故障,具有实用价值。 相似文献
6.
蚁群算法是通过模拟蚂蚁觅食而发展出的一种新的启发算法.基于群体的协作与学习,该算法已经成功地解决诸如TSP问题等多种组合优化问题.本文提出了一种改进蚁群算法.该算法根据人工蚂蚁所获得解的情况,应用一种选择策略,从而使得算法跳离局部最优解,并采用局部搜索,以获得更好的优化解.通过仿真实验获得的结果表明,该算法对于蚁群算法具有较好的改进效果. 相似文献
7.
K-均值聚类算法是一种基于划分方法的聚类算法,本文通过对传统的K-均值聚类算法的分析,提出了一种改进的K-均值算法,并对该算法的时间复杂度和空间复杂度进行了分析。该算法在计算聚类中心点时采用了一种最近邻的思想,可以有效地去除＂噪声＂和＂孤立点＂对簇中平均值（聚类中心）的影响,从而使聚类结果更加合理。最后通过实验表明该算法的有效性和正确性。 相似文献
8.
本文将聚类分析与模糊算法相结合,提出了一种新型分析算法,并将这种算法应用在住宅小区电力设施中,为建筑的节能设计提供了一种新思路。 相似文献
9.
10.
11.
软件开发是一种创造性很强的活动,由于项目的一次性和独特性的特点,因此在软件项目实施完后,很多在项目实施过程中积累起来的知识经验就会随着项目的结束而消失,从而忽略了让开发小组从历史项目中学习和总结经验的机会。本文对项目后评价的定义以及实施意义进行了描述,并对两种不同的项目后评价方法作出了比较分析,最后以某高校学生选课系统项目为例,阐述了如何实施项目后评价工作,并为该项目的日后改进提出了意见和建议。 相似文献
12.
Recently, series elasticity has been realized using pneumatics in human-robot interaction systems. Pneumatic circuits provide not only a flexible power transmission, but also the elastic element in a series elastic actuator (SEA). Pneumatic series elastic systems involve more than twice the number of parameters that influence system behaviors in comparison with rigid robotic systems. In this study, a position controller that eliminates the need of identifying a system model by employing the time delay estimation (TDE) technique is proposed for pneumatic SEA systems. The TDE technique is effective in compensating for system dynamics and all uncertainties involved in system behaviors without imposing computation load. TDE error is cancelled out through a learning way, which improves control performance and leads to asymptotic stability. A simulation study demonstrates the robustness of the proposed controllers against uncertainties imposed on the motor system as well as uncertainties on the end-effector. The simulation shows the efficacy of the learning compensation for TDE error. 相似文献
13.
14.
The effect of an imperfectly bonded laminar composite is examined in terms of the intensification of the torsional stresses operative near the imperfection which is assumed to be a circular shaped area. The laminar composite is modelled by four layers of different materials with the two outer layers being infinite in height and debonding occurs at the interface of the two inner layers. The analysis based on the application of Hankel transforms and the solution of a pair of dual integral equations can be easily extended to a multilayered system. Depending on the size of the layer thickness relative to the radius of the debonded area, delamination may take place either in a stable or unstable fashion. The analytical results also indicate that the influence of lamination tends to lower the stress intensity around an interface imperfection as compared to the stress state in a homogeneous solid containing the same imperfection. Numerical results are obtained for two special laminate geometries and discussed with reference to the pertinent parameters used in the current theory of fracture mechanics. 相似文献
15.
16.
Yuping Zhang Peng Shi Cheng-Chew Lim Hong Zhu Jiangping Hu Yong Zeng 《Journal of The Franklin Institute》2017,354(13):5519-5536
This paper proposes an approach for constructing and generating chaos from a class of three-dimensional linear switching systems via a heteroclinic loop based on the Shilnikov criterion. First, the existence of a switching rule for the system is derived by utilizing the Shilnikov heteroclinic criterion. Then a general design philosophy and its procedure of switching rule are provided to ensure that the proposed approach is applicable to engineering. Two numerical examples are presented to validate the main principle and the implementability of the scheme. Theoretical analysis and numerical simulation are used to demonstrate the feasibility and effectiveness of developed techniques. 相似文献
17.
This paper presents a new methodology for valuing new drug applications (NDA) and the R&D of pharmaceutical companies based on real option models. Traditional valuation models fail to capture the full value created by R&D to pharmaceutical companies, because they do not correctly model the nature of the process of developing a new drug. It is a series of consecutive phases from R&D to commercialisation, where each phase is in fact an option on executing the following phase, i.e. a compound option. For a NDA, the R&D phase can best be presented as a 6-fold compound option on the commercialisation phase. Using a generalisation of Geske’s compound option model, we derive a closed-form solution for a n-fold compound option model, and apply it to calculate the value of a NDA using sector average figures. 相似文献
18.
A theory is developed to describe the propagation of characteristics waves through an infinite slab of irregularities in a magneto-ionic medium. The theory makes use of the asymptotic Green's dyadic. The results show that mode conversion is possible through scattering from irregularities in an anisotropic background. Some special cases are discussed and an example is given. 相似文献
19.
自伽利略1609年将望远镜指向星空迄今,已逾400年。1959年苏联"月球2号"首次抵达月球,开启深空探测时代。1969年美国"阿波罗11号"首次载人登月,催生建立行星科学。纵观人类深空探测60年,先后出现两次探测热潮、两个深空探测大国(美国、苏联)。苏联领先又衰落,仅留给历史一个深空探测大国的背影,而美国成功转型为深空探测强国,至今在世界行星科学最前沿领航。探索浩瀚宇宙,是全人类的共同梦想。作为正在发展中的深空探测大国,我国应该怎样立足国情,走出一条有中国特色的行星科学强国之路?文章参照历史,梳理现状,畅想未来,给出我们的思考:大力培养行星科学人才,尽快实现科学引领深空探测。 相似文献
20.
《国家科学评论(英文版)》2014,(3)
Network science has atracted much atention in recent years due to its interdisciplinary applications. We witnessed the revolution of network science in 1998 and 1999 started with small-world and scale-free networks having now thousands of high-proile publications, and it seems that since 2010 studies of‘network of networks'(NON), sometimes called multilayer networks or multiplex, have atracted more and more atention. he analytic framework for NON yields a novel percolation law for n interdependent networks that shows that percolation theory of single networks studied extensively in physics and mathematics in the last 50 years is a speciic limit of the rich and very diferent general case of n coupled networks. Since then, properties and dynamics of interdependent and interconnected networks have been studied extensively, and scientists are inding many interesting results and discovering many surprising phenomena. Because most natural and engineered systems are composed of multiple subsystems and layers of connectivity, it is important to consider these features in order to improve our understanding of such complex systems. Now the study of NON has become one of the important directions in network science.In this paper, we review recent studies on the new emerging area—NON. Due to the fast growth of this ield, there are many deinitions of diferent types of NON, such as interdependent networks,interconnected networks, multilayered networks, multiplex networks and many others. here exist many datasets that can be represented as NON, such as network of diferent transportation networks including light networks, railway networks and road networks, network of ecological networks including species interacting networks and food webs, network of biological networks including gene regulation network,metabolic network and protein–protein interacting network, network of social networks and so on. Among them, many interdependent networks including critical infrastructures are embedded in space, introducing spatial constraints. hus, we also review the progress on study of spatially embedded networks. As a result of spatial constraints, such interdependent networks exhibit extreme vulnerabilities compared with their non-embedded counterparts. Such studies help us to understand, realize and hopefully mitigate the increasing risk in NON. 相似文献