期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
同步抽取变换与复小波结构相似性指数的滚动轴承性能退化评估 被引量:4
1
作者 尹爱军 张智禹 李海珠 《振动与冲击》 EI CSCD 北大核心 2020年第6期205-209,共5页
为更早地检出滚动轴承异常并量化其性能退化程度,该研究提出同步抽取变换与复小波结构相似性(SET-CWSS)指数的滚动轴承性能退化评估新方法。利用同步抽取变换(SET)对当前时刻的振动信号进行时频分析,以获得能量更加集中的时频图,将SET... 为更早地检出滚动轴承异常并量化其性能退化程度,该研究提出同步抽取变换与复小波结构相似性(SET-CWSS)指数的滚动轴承性能退化评估新方法。利用同步抽取变换(SET)对当前时刻的振动信号进行时频分析,以获得能量更加集中的时频图,将SET后得到的时频图与刚投入运行时无故障振动信号的SET时频图进行复小波结构相似性(CWSS)评价,得到当前时刻滚动轴承性能退化评估SET-CWSS指数。通过疲劳试验验证及与其他性能退化评估方法对比,结果表明:SET-CWSS指数能有效的刻画出滚动轴承性能退化过程、量化评估其性能退化程度且对滚动轴承早期异常更加敏感。 展开更多
关键词 同步抽取变换(SET) 小波结构相似性(CWSS) 滚动轴承 性能退化评估 早期异常
下载PDF
关于两个矩阵之和逆阵的讨论 被引量:1
2
作者 周梦 张玉俊 《大学数学》 2011年第5期149-151,共3页
在数域F上的n阶矩阵环中讨论两个矩阵之和的逆阵(A+B)-1与矩阵A,B之逆A-1,B-1的关系,给出复数域和实数域上等式(A+B)-1=A-1+B-1成立的充要条件.
关键词 矩阵之和 逆矩阵 复相似 相似 若当标准形
下载PDF
Hardware Optimization Technique of Full-Customized HW/SW Co-Design 被引量:1
3
作者 汤磊 魏少军 仇玉林 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第6期637-644,共8页
The hardware optimization technique of mono similarity system generation is presented based on hardware/software(HW/SW) co design.First,the coarse structure of sub graphs' matching based on full customized HW... The hardware optimization technique of mono similarity system generation is presented based on hardware/software(HW/SW) co design.First,the coarse structure of sub graphs' matching based on full customized HW/SW co design is put forward.Then,a universal sub graphs' combination method is discussed.Next,a more advanced vertexes' compression algorithm based on sub graphs' combination method is discussed with great emphasis.Experiments are done successfully with perfect results verifying all the formulas and the methods above. 展开更多
关键词 HW/SW co design CDFG mono similarity system sub graph compound graph COMBINE usage degree cost
下载PDF
Detrended Fluctuation Analysis on Correlations of Complex Networks Under Attack and Repair Strategy 被引量:4
4
作者 CHI Li-Ping YANG Chun-Bin MAKe CAI Xu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第4期765-768,共4页
We analyze the correlation properties of the Erd6s-Rdnyi random graph (RG) and the Barabdsi-Albert scale-free network (SF) under the attack and repair strategy with detrended fluctuation analysis (DFA). The maxi... We analyze the correlation properties of the Erd6s-Rdnyi random graph (RG) and the Barabdsi-Albert scale-free network (SF) under the attack and repair strategy with detrended fluctuation analysis (DFA). The maximum degree kmax, representing the local property of the system, shows similar scaling behaviors for random graphs and scale-free networks. The fluctuations are quite random at short time scales but display strong anticorrelation at longer time scales under the same system size N and different repair probability pre. The average degree 〈k〉, revealing the statistical property of the system, exhibits completely different scaling behaviors for random graphs and scale-free networks. Random graphs display long-range power-law correlations. Scale-free networks are uncorrelated at short time scales; while anticorrelated at longer time scales and the anticorrelation becoming stronger with the increase of pre. 展开更多
关键词 CORRELATIONS detrended fluctuation analysis complex networks
下载PDF
AN EFFICIENT APPROACH TO COMMENT SPAM IDENTIFICATION 被引量:1
5
作者 Yang Yuhang Zhao Tiejun Zheng Dequan Yu Hao 《Journal of Electronics(China)》 2009年第5期644-650,共7页
This paper proposes a novel approach to comment spam identification based on content analysis. Three main features including the number of links, content repetitiveness, and text similarity are used for comment spam i... This paper proposes a novel approach to comment spam identification based on content analysis. Three main features including the number of links, content repetitiveness, and text similarity are used for comment spam identification. In practice, content repetitiveness is determined by the length and frequency of the longest common substring. Furthermore, text similarity is calculated using vector space model. The precisions of preliminary experiments on comment spam identification conducted on Chinese and English are as high as 93% and 82% respectively. The results show the validity and language independency of this approach. Compared with conventional spam filtering approaches, our method requires no training, no rule sets and no link relationships. The proposed approach can also deal with new comments as well as existing comments. 展开更多
关键词 Comment spam Automatic identification Content analysis BLOG
下载PDF
Genotyping of White Spot Syndrome Virus in Chinese Cultured Shrimp during 1998-1999 被引量:7
6
作者 Yan-wei Tan Zheng-li Shi 《Virologica Sinica》 SCIE CAS CSCD 2011年第2期123-130,共8页
Recent studies showed that white spot syndrome virus(WSSV) isolates from different geographic locations share a high genetic similarity except the variable regions in ORF23/24 and ORF14/15,and variable number of tande... Recent studies showed that white spot syndrome virus(WSSV) isolates from different geographic locations share a high genetic similarity except the variable regions in ORF23/24 and ORF14/15,and variable number of tandem repeats(VNTR) within ORF94.In this study,genotyping was performed according to these three variable regions among WSSV isolates collected during 1998/1999 from Southern China.These WSSV isolates contain a deletion of 1168,5657,5898,9316 and 11093 bp,respectively in the variable region ORF23/24 compared with WSSV-TW,and a deletion of 4749 or 5622 bp in the variable region ORF14/15 relative to TH-96-II.Four types of repeat units(RUs)(6,8,9 and 13 RUs) in ORF94 were detected in these isolates,with the shortest 6 RUs as the most prevalent type.Our results provide important information for a better understanding of the spatio-temporal transmission mode and the WSSV genetic evolution lineage. 展开更多
关键词 WSSV GENOTYPING Variable region ORF23/24 ORF 14/15 ORF94 China
下载PDF
Investigation of acoustic scale effects and boundary effects for the similitude model of underwater complex shell-structure 被引量:3
7
作者 WANG San-de YANG De-sen LIU Ning 《Journal of Marine Science and Application》 2007年第1期31-35,共5页
In this paper, the acoustic scale effects and boundary effects for the similitude model of underwater complex shell-structure are investigated. The similitude conditions and relations between the similitude model and ... In this paper, the acoustic scale effects and boundary effects for the similitude model of underwater complex shell-structure are investigated. The similitude conditions and relations between the similitude model and its prototype were studied in the references. This paper investigates the acoustic scale effects for the similitude model, which are influenced by loss factor, shear and rotatory inertia. At the same time, the boundary effects which are influenced by surface sound reflection are investigated in the experiment of similitude model. The results show that the acoustic scale effects may be controlled with model designing, the boundary effects can be controlled with experimental designing between the similitude model and its prototype. 展开更多
关键词 acoustic scale effects acoustic boundary effects SIMILITUDE
下载PDF
Taxonomic Status of Daduhe Loquat (Eriobotrya prinoides var. dadunensis) 被引量:1
8
作者 Wang Yongqing Yan Juan Yang Qin Fu Yan Luo Nan Lv Xiulan 《Journal of Agricultural Science and Technology(B)》 2012年第6期659-664,共6页
The taxonomic status of Daduhe loquat (E. prinoides var. dadunensis) was studied through analyzing genetic relationships among Oakleaf loquat (E. prinoides), Daduhe loquat and Common loquat (E. japonica) using i... The taxonomic status of Daduhe loquat (E. prinoides var. dadunensis) was studied through analyzing genetic relationships among Oakleaf loquat (E. prinoides), Daduhe loquat and Common loquat (E. japonica) using inter simple sequence repeats (ISSR) molecular marker and morphologic marker in this paper. Based on ISSR marker research, the similarity coefficient between Oakleaf loquat and Common loquat was lower than the similarity coefficient between Oakleaf loquat and Daduhe loquat while the similarity coefficient between Daduhe loquat and Common loquat was intermediate. The highest additivity was obtained when Daduhe loquat was regarded as the undetermined hybrid (45.8%). The specific bands of Oakleaf loquat and Common loquat were present in Daduhe loquat. Based on morphologic traits research, Daduhe loquat was also between Oakleaf loquat and Common loquat but a little leaning to Oakleaf loquat. All the results support that Daduhe loquat was hybrid of Oakleaf loquat and Common loquat. 展开更多
关键词 Common loquat Daduhe loquat genetic relationship ISSR marker morphologic traits Oakleaf loquat taxonomic status.
下载PDF
A dynamic problem on the edges of a mode Ι crack subjected to moving unit-step loads
9
作者 吕念春 于开平 +1 位作者 程云虹 程靳 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第1期79-81,共3页
By the theory of complex functions, a dynamic problem on the edges of a mode I crack subjected to moving unit-step loads are investigated. The Riemann-Hilbert problem is easily formulated by the ways of self-similar f... By the theory of complex functions, a dynamic problem on the edges of a mode I crack subjected to moving unit-step loads are investigated. The Riemann-Hilbert problem is easily formulated by the ways of self-similar functions. The analytical solution obtained is rather simple and concise. After the solution was utilized by superposition theorem, the relevant solution on the case of arbitrary loading can be obtained. 展开更多
关键词 complex functions moving unit-step loads self-similar functions analytical solutions
下载PDF
Similarity Criterion and Scale Effect for Ship Distortion Model Under Combined Loads
10
作者 ZHANG Yi-long WEI Peng-yu +3 位作者 DAI Ze-yu WANG Lian ZENG Qing-bo TANG Qin 《船舶力学》 EI 2024年第12期1880-1890,共11页
For the ultimate strength model test evaluation of large ship structures, the distortion model with non-uniform ratio between the main size and the plate thickness size is usually adopted. It is the key to carry out s... For the ultimate strength model test evaluation of large ship structures, the distortion model with non-uniform ratio between the main size and the plate thickness size is usually adopted. It is the key to carry out scale model test to establish a distortion model similar to the real ship structure under combined load. A similarity criterion for ship distortion model under the combined action of bending moment and surface pressure was proposed, and the scale effect for the criterion was verified by a se ries of numerical analysis and model tests. The results show that the similarity criterion for ship distor tion model under combined loads has a certain scale effect. For the model tests of ship cabin struc tures, it is suggested that the scale range between the plate thickness scale and the main dimension scale should be controlled within 2:1, which can be used as a reference for distortion model design and ultimate strength test of large-scale ship structures. 展开更多
关键词 distortion model combined load similarity criteria scale effect ultimate strength test
下载PDF
New Homoclinic and Heteroclinic Solutions for Zakharov System
11
作者 王传坚 戴正德 母贵 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第11期749-753,共5页
A new type of homoclinic arid heteroclinic solutions, i.e. homoclinic and heteroclinic breather solutions, for Zakharov system are obtained using extended homoclinic test and two-soliton methods, respectively. Moreove... A new type of homoclinic arid heteroclinic solutions, i.e. homoclinic and heteroclinic breather solutions, for Zakharov system are obtained using extended homoclinic test and two-soliton methods, respectively. Moreover, the homoclinic and heteroclinic structure with local oscillation and mechanicaL feature different from homoclinic and heterocliunic solutions are investigated. Result shows complexity of dynamics for complex nonlineaR evolution system. Moreover, the similarities and differences between homoclinic (heteroclinic) breather and homoclinic (heteroclinic) tube are exhibited. These results show that the diversity of the structures of homoclinic and heteroclinic solutions. 展开更多
关键词 homoclinic wave heteroclinic wave breather type homoclinic test Zakharov system
原文传递
The ft values of the superallowed Fermi beta decays
12
作者 ALIK Abdullah Engin GEREKLIOGLU Murat SELAM Cevad 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第4期718-723,共6页
In this work, the ft values of the 0+ →0+ superallowed Fermi beta decays have been investigated. In the calculations, the shell model has been modified by Pyatov's restoration method because of the isospin breaki... In this work, the ft values of the 0+ →0+ superallowed Fermi beta decays have been investigated. In the calculations, the shell model has been modified by Pyatov's restoration method because of the isospin breaking and the transition matrix elements have been found by means of the quasi-particle random phase approximation (QRPA). 展开更多
关键词 superallowed beta decays Fermi matrix elements ft values
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部