A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic response...A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic responses. In order to reduce structural vibration, it is important to obtain the modal parameters information of a ship. However, the traditional modal parameter identification methods are not suitable since the excitation information is difficult to obtain. Natural excitation technique-eigensystem realization algorithm （NExT-ERA） is an operational modal identification method which abstracts modal parameters only from the response signals, and it is based on the assumption that the input to the structure is pure white noise. Hence, it is necessary to study the influence of harmonic excitations while applying the NExT-ERA method to a ship structure. The results of this research paper indicate the practical experiences under ambient excitation, ship model experiments were successfully done in the modal parameters identification only when the harmonic frequencies were not too close to the modal frequencies.展开更多
This paper aims to perform a comparison of deterministic and stochastic models.The stochastic modelling is a more realistic way to study the dynamics of gonorrhoea infection as compared to its corresponding determinis...This paper aims to perform a comparison of deterministic and stochastic models.The stochastic modelling is a more realistic way to study the dynamics of gonorrhoea infection as compared to its corresponding deterministic model.Also,the deterministic solution is itself mean of the stochastic solution of the model.For numerical analysis,first,we developed some explicit stochastic methods,but unfortunately,they do not remain consistent in certain situations.Then we proposed an implicitly driven explicit method for stochastic heavy alcohol epidemic model.The proposed method is independent of the choice of parameters and behaves well in all scenarios.So,some theorems and simulations are presented in support of the article.展开更多
[目的/意义]构建基于用户兴趣标签的网络社团识别模型(Fuzzy Interests and User Hybrid Model,FIUHM),揭示用户兴趣与社团形式概念间的模糊层级关系,实现多粒度属性与社团拓扑结构的层次聚类。[方法/过程]通过抽取豆瓣电影社区数据,实...[目的/意义]构建基于用户兴趣标签的网络社团识别模型(Fuzzy Interests and User Hybrid Model,FIUHM),揭示用户兴趣与社团形式概念间的模糊层级关系,实现多粒度属性与社团拓扑结构的层次聚类。[方法/过程]通过抽取豆瓣电影社区数据,实现基于用户标签的兴趣强度语义标注,利用用户相似度,获取社区用户间兴趣语义距离;将网络社区的领接矩阵映射为社团形式背景,构建社团模糊概念格,建立社团形式概念及其偏序关系集,完成社团形式概念建模;通过计算社团稳定指数,识别网络社团边界,并聚类最大独立社团,实现兴趣社团的在线检测。[结果/结论]通过对比实验,验证了FIUHM模型的有效性,实验表明将模糊形式概念分析引入网络社团识别研究,利用模糊概念格的偏序关系建模用户节点间的兴趣相似度,有利于提高社团识别的分辨率。展开更多
基金Supported by the National Natural Science Foundation of China（51079027）
文摘A ship is operated under an extremely complex environment, and waves and winds are assumed to be the stochastic excitations. Moreover, the propeller, host and mechanical equipment can also induce the harmonic responses. In order to reduce structural vibration, it is important to obtain the modal parameters information of a ship. However, the traditional modal parameter identification methods are not suitable since the excitation information is difficult to obtain. Natural excitation technique-eigensystem realization algorithm （NExT-ERA） is an operational modal identification method which abstracts modal parameters only from the response signals, and it is based on the assumption that the input to the structure is pure white noise. Hence, it is necessary to study the influence of harmonic excitations while applying the NExT-ERA method to a ship structure. The results of this research paper indicate the practical experiences under ambient excitation, ship model experiments were successfully done in the modal parameters identification only when the harmonic frequencies were not too close to the modal frequencies.
基金The first author also thanks Prince Sultan University for funding this work through research-group number RG-DES2017-01-17.
文摘This paper aims to perform a comparison of deterministic and stochastic models.The stochastic modelling is a more realistic way to study the dynamics of gonorrhoea infection as compared to its corresponding deterministic model.Also,the deterministic solution is itself mean of the stochastic solution of the model.For numerical analysis,first,we developed some explicit stochastic methods,but unfortunately,they do not remain consistent in certain situations.Then we proposed an implicitly driven explicit method for stochastic heavy alcohol epidemic model.The proposed method is independent of the choice of parameters and behaves well in all scenarios.So,some theorems and simulations are presented in support of the article.
文摘[目的/意义]构建基于用户兴趣标签的网络社团识别模型(Fuzzy Interests and User Hybrid Model,FIUHM),揭示用户兴趣与社团形式概念间的模糊层级关系,实现多粒度属性与社团拓扑结构的层次聚类。[方法/过程]通过抽取豆瓣电影社区数据,实现基于用户标签的兴趣强度语义标注,利用用户相似度,获取社区用户间兴趣语义距离;将网络社区的领接矩阵映射为社团形式背景,构建社团模糊概念格,建立社团形式概念及其偏序关系集,完成社团形式概念建模;通过计算社团稳定指数,识别网络社团边界,并聚类最大独立社团,实现兴趣社团的在线检测。[结果/结论]通过对比实验,验证了FIUHM模型的有效性,实验表明将模糊形式概念分析引入网络社团识别研究,利用模糊概念格的偏序关系建模用户节点间的兴趣相似度,有利于提高社团识别的分辨率。
