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Information Environmental sciences update referneces in Chinese journals——Selected from Acta Scientiae Circumstantiae,ISSN 0253-2468;Environental Chemistry,ISSN0254-6108;Acta Ecologica Sinica,ISSN 100-0933
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《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1993年第2期241-243,共3页
关键词 ISSN Information Environmental sciences update referneces in Chinese journals selected from Acta Scientiae Circumstantiae ISSN 0253-2468 Environental Chemistry ISSN0254-6108 Acta Ecologica Sinica ISSN 100-0933
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Table 1.FDI flows,by region and selected countries,1994-2005
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《China Textile》 2006年第4期7-7,共1页
关键词 FDI Table 1.FDI flows by region and selected countries 1994-2005
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Feature Selection Method Based on Class Discriminative Degree for Intelligent Medical Diagnosis 被引量:5
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作者 Shengqun Fang Zhiping Cai +4 位作者 Wencheng Sun Anfeng Liu Fang Liu Zhiyao Liang Guoyan Wang 《Computers, Materials & Continua》 SCIE EI 2018年第6期419-433,共15页
By using efficient and timely medical diagnostic decision making,clinicians can positively impact the quality and cost of medical care.However,the high similarity of clinical manifestations between diseases and the li... By using efficient and timely medical diagnostic decision making,clinicians can positively impact the quality and cost of medical care.However,the high similarity of clinical manifestations between diseases and the limitation of clinicians’knowledge both bring much difficulty to decision making in diagnosis.Therefore,building a decision support system that can assist medical staff in diagnosing and treating diseases has lately received growing attentions in the medical domain.In this paper,we employ a multi-label classification framework to classify the Chinese electronic medical records to establish corresponding relation between the medical records and disease categories,and compare this method with the traditional medical expert system to verify the performance.To select the best subset of patient features,we propose a feature selection method based on the composition and distribution of symptoms in electronic medical records and compare it with the traditional feature selection methods such as chi-square test.We evaluate the feature selection methods and diagnostic models from two aspects,false negative rate(FNR)and accuracy.Extensive experiments have conducted on a real-world Chinese electronic medical record database.The evaluation results demonstrate that our proposed feature selection method can improve the accuracy and reduce the FNR compare to the traditional feature selection methods,and the multi-label classification framework have better accuracy and lower FNR than the traditional expert system. 展开更多
关键词 Medical expert system EMR multi-label classification feature selection class discriminative degree
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基于VAE-CWGAN和特征统计重要性融合的网络入侵检测方法 被引量:3
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作者 刘涛涛 付钰 +1 位作者 王坤 段雪源 《通信学报》 EI CSCD 北大核心 2024年第2期54-67,共14页
针对传统入侵检测方法受限于数据集类不平衡以及所选特征代表性不强等问题,提出一种基于VAE-CWGAN和特征统计重要性融合的检测方法。首先,为提升数据质量对数据集进行预处理;其次,搭建VAE-CWGAN模型生成新样本以解决数据集类不平衡问题... 针对传统入侵检测方法受限于数据集类不平衡以及所选特征代表性不强等问题,提出一种基于VAE-CWGAN和特征统计重要性融合的检测方法。首先,为提升数据质量对数据集进行预处理;其次,搭建VAE-CWGAN模型生成新样本以解决数据集类不平衡问题,使分类模型不再偏向于多数类;再次,使用标准差、中值均值差对特征进行排序,并融合其统计重要性来进行特征选择旨在获得代表性更强的特征,从而使模型更好地学习数据信息;最后,通过一维卷积神经网络对特征选择后的混合数据集进行分类。实验结果表明,所提方法在NSL-KDD、UNSW-NB15和CIC-IDS-2017数据集上都表现出较好的性能优势,准确率分别为98.95%、96.24%和99.92%,有效提升了入侵检测性能。 展开更多
关键词 入侵检测 网络流量 类不平衡 特征选择 统计重要性融合
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Study of Swine Leukocyte Antigen Class I-3 (SLA-3) Gene for Inbreeding Wuzhishan Pig 被引量:1
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作者 SUN Jun-li MU Wu-lian +2 位作者 LIU Xiao-lin FENG Shu-tang WANG Su-rong 《Agricultural Sciences in China》 CAS CSCD 2007年第12期1502-1510,共9页
To elucidate the structure of SLA-3 alleles on inbred line of Wuzhishan pig (WZSP) population, we examined the partial exon 1, completed exon 2, and partial exon 3 of SLA-3 loci using the reverse transcription-polym... To elucidate the structure of SLA-3 alleles on inbred line of Wuzhishan pig (WZSP) population, we examined the partial exon 1, completed exon 2, and partial exon 3 of SLA-3 loci using the reverse transcription-polymerase chain reaction (RT- PCR) and the sequencing-based method in 32 WZSPs. According to pedigree and amplification results, PCR products of 8 WZSPs were selected to clone and sequence. Nine different nucleotide sequences were obtained. After comparing the DNA and protein sequences of the WZSPs SLA-3 alleles with the published GenBank SLA sequences, it was found that the SLA-3 alleles in WZSPs were all novel, but there were very few variations among them. Comparision of SLA-3 and HLA-A protein sequences indicated that there was more sequence homology. Meanwhile, the construction of a phylogenetic tree using the nucleotide sequences of 23 SLA-3 alleles and 1 HLA-A allele represented that the WZSP population owns its unique genetics resource. In this study, the alleles of SLA-3 on WZSP group were successfully detected and analyzed, which provided the firm basis on the genotype of SLA-3 for breeding specific haplotypes WZSPs. 展开更多
关键词 inbreeding Wuzhishan pig leucocyte antigen SLA classical class 1-3 gene RT-PCR
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MHC Class I Exon 4 in the Multiocellated Racerunners(Eremias multiocellata): Polymorphism, Duplication and Selection
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作者 Xiuyun YUAN Xiaomao ZENG Xianguang GUO 《Asian Herpetological Research》 SCIE 2014年第2期91-103,共13页
The major histocompatibility complex (MHC) is a dynamic genetic region with an essential role in the adaptive immunity of jawed vertebrates. The MHC polymorphism is affected by many processes such as birth-and- deat... The major histocompatibility complex (MHC) is a dynamic genetic region with an essential role in the adaptive immunity of jawed vertebrates. The MHC polymorphism is affected by many processes such as birth-and- death evolution, gene conversion, and concerted evolution. Studies investigating the evolution of MHC class I genes have been biased toward a few particular taxa and model species. However, the investigation of this region in nonavian reptiles is still in its infancy. We present the first characterization of MHC class I genes in a species from the family Lacertidae. We assessed genetic diversity and a role of selection in shaping the diversity of MHC class I exon 4 among 37 individuals of Eremias multiocellata from a population in Lanzhou, China. We generated 67 distinct DNA sequences using cloning and sequencing methods, and identified 36 putative functional variants as well as two putative pseudogene-variants. We found the number of variants within an individual varying between two and seven, indicating that there are at least four MHC class I loci in this species. Gene duplication plays a role in increasing copy numbers of MHC genes and allelic diversity in this species. The class I exon 4 sequences are characteristic of low nucleotide diversity. No signal of recombination is detected, but purifying selection is detected in β2-microglobulin interaction sites and some other silent sites outside of the function-constraint regions. Certain identical alleles are shared by Eremias multiocellata and E. przewalskii and E. brenchleyi, suggesting trans-species polymorphism. The data are compatible with a birth-and-death model of evolution. 展开更多
关键词 MHC class I Eremias multiocellata trans-species polymorphism balancing selection purifying selection birth-and-death evolution
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Allelic Polymorphism,Gene Duplication and Balancing Selection of MHC Class ⅡB Genes in the Omei Treefrog(Rhacophorus omeimontis)
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作者 Li HUANG Mian ZHAO +1 位作者 Zhenhua LUO Hua WU 《Asian Herpetological Research》 SCIE CSCD 2016年第1期1-11,共11页
The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major hist... The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major histocompatibility complex(MHC) class Ⅱ molecules, the characterization and the evolution of amphibian MHC class Ⅱ genes have attracted increasing attention. The polymorphism of MHC class Ⅱ genes was found to be correlated with susceptibility to fungal pathogens in many amphibian species, suggesting the importance of studies on MHC class Ⅱ genes for amphibians. However, such studies on MHC class Ⅱ gene evolution have rarely been conducted on amphibians in China. In this study, we chose Omei treefrog(Rhacophorus omeimontis), which lived moist environments easy for breeding bacteria, to study the polymorphism of its MHC class Ⅱ genes and the underlying evolutionary mechanisms. We amplified the entire MHC class ⅡB exon 2 sequence in the R. omeimontis using newly designed primers. We detected 102 putative alleles in 146 individuals. The number of alleles per individual ranged from one to seven, indicating that there are at least four loci containing MHC class ⅡB genes in R. omeimontis. The allelic polymorphism estimated from the 102 alleles in R. omeimontis was not high compared to that estimated in other anuran species. No significant gene recombination was detected in the 102 MHC class ⅡB exon 2 sequences. In contrast, both gene duplication and balancing selection greatly contributed to the variability in MHC class ⅡB exon 2 sequences of R. omeimontis. This study lays the groundwork for the future researches to comprehensively analyze the evolution of amphibian MHC genes and to assess the role of MHC gene polymorphisms in resistance against extracellular pathogens for amphibians in China. 展开更多
关键词 MHC class ⅡB POLYMORPHISM gene duplication balancing selection Rhacophorus omeimontis
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Zooplankton community size-structure change and mesh size selection under the thermal stress caused by a power plant in a semi-enclosed bay
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作者 Qianwen Shao Yifeng Zhu +3 位作者 Meixia Dai Xia Lin Chengxu Zhou Xiaojun Yan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第8期62-70,共9页
Zooplankton samples were collected using 505, 160 and 77 μm mesh nets around a power plant during four seasons in 2011. We measured total length of zooplankton and divided zooplankton into seven size classes in order... Zooplankton samples were collected using 505, 160 and 77 μm mesh nets around a power plant during four seasons in 2011. We measured total length of zooplankton and divided zooplankton into seven size classes in order to explore how zooplankton community size-structure might be altered by thermal discharge from power plant. The total length of zooplankton varied from 93.7 to 40 074.7 μm. The spatial distribution of mesozooplankton(200-2 000 μm) populations were rarely affected by thermal discharge, while macro-(2 000-10 000 μm)and megalo-zooplankton(>10 000 μm) had an obvious tendency to migrate away from the outfall of power plant.Thus, zooplankton community tended to become smaller and biodiversity reduced close to power plant.Moreover, we compared the zooplankton communities in three different mesh size nets. Species richness,abundance, evenness index and Shannon-Wiener diversity index of the 505 μm mesh size were significantly lower than those recorded from the 160 and 77 μm mesh size. Average zooplankton abundance was highest in the 77 μm mesh net((27 690.0±1 633.7) ind./m^3), followed by 160 μm mesh net((9 531.1±1 079.5) ind./m^3), and lowest in 505 μm mesh net((494.4±104.7) ind./m^3). The ANOSIM and SIMPER tests confirmed that these differences were mainly due to small zooplankton and early developmental stages of zooplankton. It is the first time to use the 77 μm mesh net to sample zooplankton in such an environment. The 77 μm mesh net had the overwhelming abundance of the copepod genus Oithona, as an order of magnitude greater than recorded for 160 μm mesh net and 100% loss through the 505 μm mesh net. These results indicate that the use of a small or even multiple sampling net is necessary to accurately quantify entire zooplankton community around coastal power plant. 展开更多
关键词 ZOOPLANKTON coastal power plant temperature elevation size class community structure mesh size selection
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Molecular mapping of a novel wheat powdery mildew resistance gene Ml92145E8-9 and its application in wheat breeding by marker-assisted selection
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作者 Xiaocheng Yu Shizhong Ren +8 位作者 Lanfei Zhao Jun Guo Yinguang Bao Yingxue Ma Hongwei Wang Herbert W.Ohm Dazhao Yu Hongjie Li Lingrang Kong 《The Crop Journal》 SCIE CAS CSCD 2018年第6期621-627,共7页
Powdery mildew, caused by Blumeria graminis f. sp. tritici(Bgt), is one of the most devastating diseases of common wheat(Triticum aestivum L.). The wheat line 92145 E8-9 is immune to Bgt isolate E09. Genetic analysis ... Powdery mildew, caused by Blumeria graminis f. sp. tritici(Bgt), is one of the most devastating diseases of common wheat(Triticum aestivum L.). The wheat line 92145 E8-9 is immune to Bgt isolate E09. Genetic analysis reveals that the powdery mildew resistance in 92145 E8-9 is controlled by a single dominant gene, temporarily designated Ml92145 E8-9. Bulkedsegregant analysis(BSA) with simple sequence repeat(SSR) markers indicates that Ml92145 E8-9 is located on chromosome 2 AL. According to the reactions of 92145 E8-9,VPM1(Pm4 b carrier), and Lankao 906(PmLK906 carrier) to 14 Bgt isolates, the resistance spectrum of 92145 E8-9 differs from those of Pm4 b and PmLK906, both of which were previously localized to 2 AL. To test the allelism among Ml92145 E8-9, Pm4 b and PmLK906, two F2 populations of 92145 E8-9 × VPM1(Pm4 b) and 92145 E8-9 × Lankao 906(PmLK906) were developed in this study. Screening of 784 F2 progeny of 92145 E8-9 × VPM1 and 973 F2 progeny of 92145 E8-9 × Lankao 906 for Bgt isolate E09 identified 37 and 19 susceptible plants, respectively. These findings indicated that Ml92145 E8-9 is non-allelic to either Pm4 b or PmLK906. Thus, Ml92145 E8-9 is likely to be a new powdery mildew resistance gene on2 AL. New polymorphic markers were developed based on the collinearity of genomic regions of Ml92145 E8-9 with the reference sequences of the International Wheat Genome Sequencing Consortium(IWGSC). Ml92145 E8-9 was mapped to a 3.6 c M interval flanked by molecular markers Xsdauk13 and Xsdauk682. This study also developed five powdery mildew-resistant wheat lines(SDAU3561, SDAU3562, SDAU4173, SDAU4174, and SDAU4175)using flanking marker-aided selection. The markers closely linked to Ml92145 E8-9 would be useful in marker-assisted selection for wheat powdery mildew resistance breeding. 展开更多
关键词 Marker-assisted selectION Ml92145E8-9 Powdery MILDEW TRITICUM AESTIVUM L.
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Grain selection and growth orientation of prior-β phase for Ti-6-4 during additive manufacturing:insights from a modeling perspective
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作者 Wei-zhao Sun Fei-hu Shan +2 位作者 Nan-fu Zong Hong-biao Dong Tao Jing 《China Foundry》 SCIE CAS 2021年第2期83-93,共11页
The microstructure of Ti-6-4 components produced by additive manufacturing suffers from the coarse and elongated prior-β grain,which leads to a decrease of the tensile behavior and the occurrence of anisotropy.To und... The microstructure of Ti-6-4 components produced by additive manufacturing suffers from the coarse and elongated prior-β grain,which leads to a decrease of the tensile behavior and the occurrence of anisotropy.To understand and control the grain evolution,a multiscale simulation is applied to investigate the relationship between the grain selection,growth orientation,and the molten pool morphology with the different deposition layer numbers and processing parameters.The accuracy of the simulation is validated by experiments in both qualitative and quantitative ways.Results show that when the grain with unfavorable orientation loses the competitive growth with its neighbors,there will be a great chance that the blocked grain is eliminated in the following layer-and-layer deposition,which leads to the increase of the grain width.The size of the molten pool increases remarkably as the layer number increases,which lays a heavy burden on the stability of the molten pool.The analytical relationship between the molten pool morphology and the grain growth orientation is also deduced.The flat molten pool causes the grains with the <001> direction close to the building direction to have greater survival potential.Besides,decreasing the line power energy shows little effect on the stability of the molten pool and the grain growth orientation,especially when the deposited layer number is large.The revealing mechanisms will help in understanding and further controlling the grain evolution. 展开更多
关键词 additive manufacturing Ti-6-4 simulation grain selection grain growth
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基于特征选择与改进的Tri-training的半监督网络流量分类
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作者 李道全 祝圣凯 +1 位作者 翟豫阳 胡一帆 《计算机工程与应用》 CSCD 北大核心 2024年第23期275-285,共11页
网络流量分类对网络管理意义重大,目前基于机器学习的流量分类方法存在标注瓶颈、样本不平衡的问题。针对这两个问题,提出一种基于特征选择与改进的Tri-training算法结合的半监督网络流量分类模型。根据最大信息系数、皮尔逊系数选择出... 网络流量分类对网络管理意义重大,目前基于机器学习的流量分类方法存在标注瓶颈、样本不平衡的问题。针对这两个问题,提出一种基于特征选择与改进的Tri-training算法结合的半监督网络流量分类模型。根据最大信息系数、皮尔逊系数选择出与类高度相关但彼此不相关的特征,利用改进的Relief F选择出有利于少数类分类的特征,并将选择出的特征组合成最优特征子集缓解不平衡数据对分类的影响。结合集成思想,优化迭代和加权决策改进传统Tri-training算法,利用改进的Tri-training算法解决标注瓶颈问题。在Moore数据集上进行了实验,实验结果表明提出的方法在利用不平衡的少量有标记的数据下在F-measure上达到了95.26%,与先进的机器学习算法和原始Tri-training方法及其一些改进算法相比具有更好的分类性能。 展开更多
关键词 半监督网络 类不平衡 网络流量分类 特征选择 TRI-TRAINING
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基于MCFS-R-Vine Copula的过程故障检测
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作者 魏英鹏 王丽 《计算机仿真》 2024年第6期428-434,共7页
R-Vine Copula模型因其对复杂高维变量相互关系具有的良好的刻画能力,逐渐在化工过程监控领域得到重视。在以往的R-Vine Copula模型应用中,对于数据变量处理采用两种方法,降维和不降维,但这会破坏数据结构或者增加R-Vine Copula模型构... R-Vine Copula模型因其对复杂高维变量相互关系具有的良好的刻画能力,逐渐在化工过程监控领域得到重视。在以往的R-Vine Copula模型应用中,对于数据变量处理采用两种方法,降维和不降维,但这会破坏数据结构或者增加R-Vine Copula模型构建的成本。基于此,提出一种结合多类特征选择(MCFS)的方法MCFS-RVC,来达到保留数据结构以及降低R-Vine Copula模型构建的成本的目的,并将其应用在化工过程监控领域。对R-Vine Copula模型得到的概率密度函数值进行对数转化,依据核密度估计理论对转化的数值进行密度估计形成相应的概率密度指标poutliers,实现了对非线性非高斯过程故障的实时检测。通过对TE(Tennessee Eastman)过程的仿真,验证了所提出方法的有效性和优越性。 展开更多
关键词 过程监控 故障检测 多类特征选择 核密度估计
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Breeding and Cultivation Techniques of Edible Sunflower Variety AR9-9293 被引量:3
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作者 刘胜利 柳延涛 +3 位作者 王鹏 李万云 王波 段维 《Agricultural Science & Technology》 CAS 2017年第9期1642-1644,共3页
Edible sunflower variety AR9-9293 was approved by the Sunflower Variety Appraisal Committee with the country Identification number of sunflower 2015005. This paper introduced the breeding process, yield performance an... Edible sunflower variety AR9-9293 was approved by the Sunflower Variety Appraisal Committee with the country Identification number of sunflower 2015005. This paper introduced the breeding process, yield performance and characteristics, and the high-yield cultivation technology of new edible sunflower variety AR9-9293. The promotion of edible sunflower varieties and cultivation technology could achieve the effects of improving the level of the sunflower cultivation, promoting the development of rural and agricultural economy and increasing farmers' income, as well as positively promoting development of the society and adjusting agricultural industry structure. 展开更多
关键词 New oil sunflower hybrid AR9-9293 selectION Cultivation technology
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“双一流”建设高校如何遴选研究生导师--基于政策文本的计量分析 被引量:14
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作者 王传毅 肖灿 彭湃 《江苏高教》 CSSCI 北大核心 2020年第5期22-28,共7页
基于导师遴选办法的计量分析发现:"双一流"建设高校在导师任职的基本条件上有刚性标准,但也探索柔性的遴选机制;教学要求主要集中于教学工作量;科研要求具有明确的量化标准,且覆盖论文、课题、知识转化多个方面,在校际呈现层... 基于导师遴选办法的计量分析发现:"双一流"建设高校在导师任职的基本条件上有刚性标准,但也探索柔性的遴选机制;教学要求主要集中于教学工作量;科研要求具有明确的量化标准,且覆盖论文、课题、知识转化多个方面,在校际呈现层次性特征;博士生导师遴选大多数是由学校审批,硕士生导师更多是由学院组织选拔聘任。大多数高校细化师德师风、学术伦理等评价规则,建立了明晰的"负面清单"。优化导师遴选需要回归导师职业活动的本身,更加注重教学过程、研究生指导的评价,并关注新型指导模式。 展开更多
关键词 “双一流”建设高校 研究生导师 遴选
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连续属性离散化的Imp-Chi2算法 被引量:2
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作者 桑雨 闫德勤 +1 位作者 刘磊 梁宏霞 《计算机工程》 CAS CSCD 北大核心 2008年第17期39-41,共3页
连续属性离散化是机器学习和数据挖掘领域中的一个重要问题,离散化是否合理决定着表达和提取相关信息的准确性。经过研究Chi2系列算法,提出一种新的基于属性重要性的连续属性离散化方法——Imp-Chi2算法,该算法依据属性重要性程度对属... 连续属性离散化是机器学习和数据挖掘领域中的一个重要问题,离散化是否合理决定着表达和提取相关信息的准确性。经过研究Chi2系列算法,提出一种新的基于属性重要性的连续属性离散化方法——Imp-Chi2算法,该算法依据属性重要性程度对属性离散化的顺序进行了合理的调整,能够更准确地对连续属性进行离散化。文章通过C4.5和支持向量机分别对离散化后的结果进行了实验,在实验过程中,提出一种训练集类比例抽取方法,避免了训练集随机抽取的不均匀性。实验结果证明了所提算法的有效性。 展开更多
关键词 连续属性离散化 CHI2算法 属性重要性 训练集类比例抽取
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基于FS-PCA-MSCD的地铁轴承可视化诊断方法 被引量:1
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作者 杨建伟 白永亮 +1 位作者 武慧杰 化凤芳 《北京建筑大学学报》 2016年第3期116-120,131,共6页
针对地铁轴承的可视化故障诊断能力,本文提出了基于特征选择(Feature Selection,FS)与多尺度类距离(Multi Scale Class Distance,MSCD)的轴承故障诊断方法.首先对地铁齿轮箱轴承振动信号进行采集,获得不同故障类型的轴承故障样本集;然... 针对地铁轴承的可视化故障诊断能力,本文提出了基于特征选择(Feature Selection,FS)与多尺度类距离(Multi Scale Class Distance,MSCD)的轴承故障诊断方法.首先对地铁齿轮箱轴承振动信号进行采集,获得不同故障类型的轴承故障样本集;然后基于FS方法提取故障样本中存在的敏感特征值,并利用获得的特征向量进行主成分分析(Principal Component Analysis,PCA),基于MSCD方法对各故障聚类进行再分类,提高故障类的可分性,获得可视化程度高的故障诊断结果.利用该方法对地铁齿轮箱轴承故障数据进行可视化故障诊断,诊断结果表明该方法能够提取敏感故障特征并获得具有较高故障可分性与可视化的诊断结果.该方法为地铁轴承在线故障分析能力提供了技术支持,在地铁运行维护与故障诊断方面均具有广阔的应用前景. 展开更多
关键词 地铁轴承 特征选择 类距离 可视化诊断
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HSMC-SVM的二次逼近快速训练算法 被引量:2
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作者 徐图 罗瑜 何大可 《电子与信息学报》 EI CSCD 北大核心 2008年第11期2746-2749,共4页
HSMC-SVM是一种直接型高速多类支持向量机,适合用于类别较多的分类场合,但由于SMO算法采用经验方法选择工作集,使得在用SMO算法训练HSMC-SVM时,收敛速度较慢。为提高HSMC-SVM的收敛速度,该文提出用基于二次逼近的可行方向法来训练HSMC-S... HSMC-SVM是一种直接型高速多类支持向量机,适合用于类别较多的分类场合,但由于SMO算法采用经验方法选择工作集,使得在用SMO算法训练HSMC-SVM时,收敛速度较慢。为提高HSMC-SVM的收敛速度,该文提出用基于二次逼近的可行方向法来训练HSMC-SVM,并使用了样本缩减策略。实验表明,这种方法可以有效提高HSMC-SVM的收敛速度,其收敛速度已经超过了基于libsvm的组合多类支持向量机,完全可以用于分类类别多、样本数量大的分类场合。 展开更多
关键词 超球体多类支持向量机 SMO训练算法 工作集选择:二次逼近
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基于分治策略的NP-MLSTM非侵入式负荷辨识方法 被引量:5
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作者 易灵芝 黄其森 +3 位作者 刘文翰 赵健 陈章 罗显光 《电力系统及其自动化学报》 CSCD 北大核心 2021年第10期112-118,共7页
为降低电力负荷数据样本类别不平衡、提高负荷辨识精度,提出一种基于分治策略的二分类多层长短时记忆网络模型非侵入式负荷辨识方法。首先,对负荷样本进行平衡化处理,降低样本间的不平衡度;然后,选择合适的特征变量,并进行特征变量与样... 为降低电力负荷数据样本类别不平衡、提高负荷辨识精度,提出一种基于分治策略的二分类多层长短时记忆网络模型非侵入式负荷辨识方法。首先,对负荷样本进行平衡化处理,降低样本间的不平衡度;然后,选择合适的特征变量,并进行特征变量与样本标签的相关性分析;接着,利用分治策略的思想将多分类问题转化为多层择优二分类问题,构建基于分治策略的NP-MLSTM非侵入式负荷辨识模型;最后,选用公开数据集对55户家庭中的11种不同类别的电器进行负荷辨识测试,并与其他模型进行效果对比。结果表明,本文提出的负荷辨识模型综合精确度达到92%以上,各性能指标均优于其他模型。 展开更多
关键词 非侵入式负荷辨识 类别不平衡 特征选取 核典型关联分析 长短时记忆网络 辨识精度
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强相关树基因选择方法及AE-RSVM分类研究
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作者 张岩 闫德勤 +1 位作者 吕志超 郑宏亮 《计算机工程与应用》 CSCD 2013年第17期245-249,共5页
对肿瘤基因表达谱进行分析,从而有效区分正常样本与肿瘤样本的关键是:准确找出能够决定样本类别的最少特征基因,并用一个性能较好的分类器进行分类预测。针对该问题,用修订的特征记分准则(RFSC)去除分类无关基因;对两两冗余法进行改进,... 对肿瘤基因表达谱进行分析,从而有效区分正常样本与肿瘤样本的关键是:准确找出能够决定样本类别的最少特征基因,并用一个性能较好的分类器进行分类预测。针对该问题,用修订的特征记分准则(RFSC)去除分类无关基因;对两两冗余法进行改进,提出强相关树法用于冗余基因的去除;对粗糙支持向量机(RSVM)改进,提出近似等价粗糙支持向量机(AE-RSVM)对样本集进行分类测试。以肿瘤样本集为例进行测试,实验结果表明了提出方法的可行性和有效性。 展开更多
关键词 基因表达谱 肿瘤分类 基因选择 支持向量机 等价类
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气相色谱-负化学源质谱联用法测定水产品及食用油中氟乐灵的残留量 被引量:9
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作者 王莉 夏广辉 +5 位作者 沈伟健 吴斌 张睿 陆慧媛 沈崇钰 赵增运 《色谱》 CAS CSCD 北大核心 2014年第3期314-317,共4页
建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取,4℃冷藏后,采用分散型固相萃取法净化,由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证... 建立了一种可用于水产品及食用油中氟乐灵残留量分析的分散型固相萃取-气相色谱-负化学离子源质谱方法。水产品及食用油经乙腈提取,4℃冷藏后,采用分散型固相萃取法净化,由气相色谱-负化学离子源质谱选择离子监测技术进行测定与确证,同位素内标法定量。在1~40μg / L 范围内氟乐灵农药的线性关系良好;方法定量限(LOQ)为0.02μg / kg;对鳗鱼、烤鳗、梭子蟹、小龙虾、猪油和橄榄油等6种复杂基质进行1.0、2.0和3.0μg / kg 等3个水平的添加回收试验,平均回收率均处于80%~100%之间,RSD≤10.3%;无干扰现象出现。该方法可作为水产品及食用油中氟乐灵残留检测的确证方法。 展开更多
关键词 分散型固相萃取 气相色谱-负化学离子源质谱联用 选择离子监测 氟乐灵 水产品 食用油 disperse solid phase extraction( DSPE) gas chromatography-negative chemical ionization mass SPECTROMETRY ( GC-MS NCI ) selected ion monitoring ( SIM )
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