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Air-combat behavior data mining based on truncation method 被引量:1
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作者 Yunfei Yin Guanghong Gong Liang Han 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第5期827-834,共8页
This paper considers the problem of applying data mining techniques to aeronautical field.The truncation method,which is one of the techniques in the aeronautical data mining,can be used to efficiently handle the air-... This paper considers the problem of applying data mining techniques to aeronautical field.The truncation method,which is one of the techniques in the aeronautical data mining,can be used to efficiently handle the air-combat behavior data.The technique of air-combat behavior data mining based on the truncation method is proposed to discover the air-combat rules or patterns.The simulation platform of the air-combat behavior data mining that supports two fighters is implemented.The simulation experimental results show that the proposed air-combat behavior data mining technique based on the truncation method is feasible whether in efficiency or in effectiveness. 展开更多
关键词 air-combat truncation method behavior mining basic fighter maneuvers(BFMs) data mining.
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DDFS spurious signals due to amplitude quantization in absence of phase-accumulator truncation
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作者 Tian Xinguang Liu Xin +1 位作者 Chen Hong Duan Miyi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第3期485-492,共8页
Spurious signals in direct digital frequency synthesizers (DDFSs) are partly caused by amplitude quantization and phase truncation, which affect their application to many wireless telecommunication systems. These si... Spurious signals in direct digital frequency synthesizers (DDFSs) are partly caused by amplitude quantization and phase truncation, which affect their application to many wireless telecommunication systems. These signals are deterministic and periodic in the time domain, so they appear as line spectra in the frequency domain. Two types of spurious signals due to amplitude quantization are exactly formulated and compared in the time and frequency domains respectively. Then the frequency spectra and power levels of the spurious signals due to amplitude quantization in the absence of phase-accumulator truncation are emphatically analyzed, and the effects of the DDFS parameter variations on the spurious signals are thoroughly studied by computer simulation. And several important conclusions are derived which can provide theoretical support for parameter choice and spurious performance evaluation in the application of DDFSs. 展开更多
关键词 spurious signal direct digital frequency synthesizer amplitude quantization phase truncation power level.
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Novel analysis method for the spurious spectrum of direct digitalfrequency synthesizer in the presence of phase truncation
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作者 XieRenhong ShiXiangquan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第2期301-304,共4页
Based on the analysis of the spurious introduced by phase accumulation truncation which was made by Nicholas, a new simplified algorithm for spurious spectrum in the presence of phase truncation is presented by using ... Based on the analysis of the spurious introduced by phase accumulation truncation which was made by Nicholas, a new simplified algorithm for spurious spectrum in the presence of phase truncation is presented by using the mapping mathematics and number theoretic method, it is possible to precisely analyze the spurious location and the spurious amplitude introduced by phase truncation in practical applications by computer. 展开更多
关键词 direct digital frequency synthesis phase truncation SPURIOUS mapping.
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On some multiple solutions to a p(x)-Laplace equation with supercritical growth
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作者 Lin Zhao 《中国科学技术大学学报》 北大核心 2025年第5期15-20,14,I0001,共8页
We consider the multiplicity of solutions to a p(x)-Laplacian problem involving supercritical Sobolev growth via Ricceri’s principle.By means of truncation combined with De Giorgi iteration,we can extend the results ... We consider the multiplicity of solutions to a p(x)-Laplacian problem involving supercritical Sobolev growth via Ricceri’s principle.By means of truncation combined with De Giorgi iteration,we can extend the results of subcritical and critical growth to supercritical growth and obtain at least three solutions to the p(x)-Laplacian problem. 展开更多
关键词 degenerate elliptic equations a priori estimates truncated technique supercritical Sobolev exponent
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Real pairwise completely positive matrices
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作者 ZHOU Anwa HE Jiayi 《运筹学学报(中英文)》 北大核心 2025年第3期160-178,共19页
In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise c... In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise completely positive(RPCP)decomposition.We study the properties of RPCP matrices and give some necessary and sufficient conditions for a matrix pair to be RPCP.First,we give an equivalent decomposition for the RPCP matrices,which is different from the RPCP-decomposition and show that the matrix pair(X,X)is RPCP if and only if X is completely positive.Besides,we also prove that the RPCP matrices checking problem is equivalent to the separable completion problem.A semidefinite algorithm is also proposed for detecting whether or not a matrix pair is RPCP.The asymptotic and finite convergence of the algorithm are also discussed.If it is RPCP,we can further give a RPCP-decomposition for it;if it is not,we can obtain a certificate for this. 展开更多
关键词 real pairwise completely positive matrices truncated moment problem semidefinite relaxation
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Continuity of truncated Hardy-Littlewood maximal function
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作者 WANG Yidong WU Jia YAN Dunyan 《中国科学院大学学报(中英文)》 CAS CSCD 北大核心 2024年第6期721-727,共7页
This paper focuses on the continuity of the truncated Hardy-Littlewood maximal function.We first show that the truncated Hardy-Littlewood maximal function is lower semi-continuous.Then by investigating the behavior of... This paper focuses on the continuity of the truncated Hardy-Littlewood maximal function.We first show that the truncated Hardy-Littlewood maximal function is lower semi-continuous.Then by investigating the behavior of the truncated Hardy-Littlewood maximal function when the truncated parameterγchanges,we obtain an equivalent condition of the continuity of the truncated Hardy-Littlewood maximal function. 展开更多
关键词 Hardy-Littlewood maximal function truncation CONTINUITY truncated parameter
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丘陵山区地块尺度耕地生态效率及其影响因素分析 被引量:10
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作者 许标文 王海平 +1 位作者 杨军 郑百龙 《福建农业学报》 CAS 北大核心 2018年第12期1317-1323,共7页
耕地生态效率是评价耕地利用经济与环境绩效的有效测度。基于福建丘陵山区146块耕地的微观调查数据,利用Bootstrap-DEA模型计算耕地生态效率和投入变量的生态效率,并通过Double Bootstrap Truncated回归模型分析耕地生态效率影响因素。... 耕地生态效率是评价耕地利用经济与环境绩效的有效测度。基于福建丘陵山区146块耕地的微观调查数据,利用Bootstrap-DEA模型计算耕地生态效率和投入变量的生态效率,并通过Double Bootstrap Truncated回归模型分析耕地生态效率影响因素。研究发现:Bootstrap纠偏后的福建省丘陵山区耕地生态效率为0.610 7,化肥、农药及能源等投入变量的生态效率分别为0.679 9、0.575 5、0.481 9;Truncated回归结果显示耕地规模、教育程度、产品认证及复种指数对生态效率有显著影响,环境补贴对生态效率改善还未起作用。表明福建省丘陵山区耕地生态效率整体较为低下,应进一步推动土地适度规模经营、推广农业绿色发展技术及加大绿色生态农业补贴力度,以提高耕地生态效率。 展开更多
关键词 生态效率 Bootstrap-DEA DOUBLE BOOTSTRAP Truncated回归模型 地块尺度 丘陵山区
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Engineered Plant Minichromosome and Its Application in Genomics and Genetic Engineering
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作者 YU Wei-chang(The Chinese University of Hongkong,Hongkong,China) 《棉花学报》 CSCD 北大核心 2008年第S1期39-,共1页
Engineered minichromosomes have been constructed as novel artificial chromosome platforms for future genetic engineering in maize.We demonstrated that minichromosomes could be created by telomere-mediated chromosomal ... Engineered minichromosomes have been constructed as novel artificial chromosome platforms for future genetic engineering in maize.We demonstrated that minichromosomes could be created by telomere-mediated chromosomal truncation of both normal A chromosomes and the supernumerary 展开更多
关键词 TELOMERE chromosome GENOMICS CHROMOSOMAL truncation created maize TRANSGENE wheat confer
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国外高档龙门式加工中心的可靠性综合评价(英文) 被引量:1
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作者 倪文凯 于丰博 +1 位作者 隗纪强 朴成道 《机床与液压》 北大核心 2015年第24期25-29,共5页
采用定时截尾试验法收集了2组国外高档龙门式加工中心的故障数据。通过传统的可靠性分析方法分别计算了不同截尾次数下的MTBF和MTTFF,然后通过动态加权法确定了不同样本下的MTTFF与MTBF的权重,最后通过波达计数函数对这两组机床进行了... 采用定时截尾试验法收集了2组国外高档龙门式加工中心的故障数据。通过传统的可靠性分析方法分别计算了不同截尾次数下的MTBF和MTTFF,然后通过动态加权法确定了不同样本下的MTTFF与MTBF的权重,最后通过波达计数函数对这两组机床进行了排序。结果表明:A2组明显好于A1组,同时也表明多次截尾实验下的动态加权法充分体现了评价对象的"质差"和"量差",是一种切实可行的数控机床可靠性评价方法。 展开更多
关键词 FAILURE TRUNCATED testing Dynamic weighting method Mean time to FIRST failure GANTRY machiningcenter
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海豚隔离期间的医疗保健
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作者 赵琪 林英涛 《海洋科学》 CAS CSCD 北大核心 2006年第8期4-5,共2页
总结了北京海洋馆对2003年3月20日从日本购进的6条海豚在隔离期间所采取的医疗保健措施。针对隔离期内6条海豚表现出的厌食、消瘦、贫血、肠炎、便秘等症状,分别采取了驱虫、补充维生素、处理外伤、补液等保健和医疗措施。6条海豚身体... 总结了北京海洋馆对2003年3月20日从日本购进的6条海豚在隔离期间所采取的医疗保健措施。针对隔离期内6条海豚表现出的厌食、消瘦、贫血、肠炎、便秘等症状,分别采取了驱虫、补充维生素、处理外伤、补液等保健和医疗措施。6条海豚身体恢复健康,已顺利度过隔离期。这一系列医疗保健措施的制定,充分考虑了北京海洋馆的实际情况,同时汲取了国内外该领域的经验,相信可为国内外同行提供有益的帮助。 展开更多
关键词 瓶鼻海豚(Tursiops truncates) 隔离期 医疗保健
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Strength of Intramolecular Hydrogen Bonds 被引量:1
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作者 JIANG Xiaoyu WU Wei MO Yirong 《物理化学学报》 SCIE CAS CSCD 北大核心 2018年第3期278-285,共8页
The concept of resonance-assisted hydrogen bonds(RAHBs)highlights the synergistic interplay between theπ-resonance and hydrogen bonding interactions.This concept has been well-accepted in academia and is widely used ... The concept of resonance-assisted hydrogen bonds(RAHBs)highlights the synergistic interplay between theπ-resonance and hydrogen bonding interactions.This concept has been well-accepted in academia and is widely used in practice.However,it has been argued that the seemingly enhanced intramolecular hydrogen bonding(IMHB)in unsaturated compounds may simply be a result of the constraints imposed by theσ-skeleton framework.Thus,it is crucial to estimate the strength of IMHBs.In this work,we used two approaches to probe the resonance effect and estimate the strength of the IMHBs in the two exemplary cases of the enol forms of acetylacetone and o-hydroxyacetophenone.One approach is the block-localized wavefunction(BLW)method,which is a variant of the ab initio valence bond(VB)theory.Using this approach,it is possible to derive the geometries and energetics with resonance shut down.The other approach is Edmiston’s truncated localized molecular orbital(TLMO)technique,which monitors the energy changes by removing the delocalization tails from localized molecular orbitals.The integrated BLW and TLMO studies confirmed that the hydrogen bonding in these two molecules is indeed enhanced byπ-resonance,and that this enhancement is not a result ofσconstraints. 展开更多
关键词 Resonance-assisted hydrogen bond Bond strength Valence bond Block-localized wavefunction Truncated localized molecular orbital
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