期刊文献+
共找到178篇文章
< 1 2 9 >
每页显示 20 50 100
Bacterial Protein Profiling——Comparison of Three Mass Spectrometry Methodologies
1
作者 JIANG Yan CHEN Yanlin +4 位作者 SONG Gaoyu CHEN Yanyan BAI Jing ZHU Yingdi LI Juan 《高等学校化学学报》 SCIE EI CAS CSCD 北大核心 2024年第11期158-173,共16页
Profiling the protein composition of bacteria is essential for understanding their biology,physiology and interaction with environment.Mass spectrometry has become a pivotal tool for protein analysis,facilitating the ... Profiling the protein composition of bacteria is essential for understanding their biology,physiology and interaction with environment.Mass spectrometry has become a pivotal tool for protein analysis,facilitating the examination of expression levels,molecular masses and structural modifications.In this study,we compared the performance of three widely-used mass spectrometry methods,i.e.,matrix-assisted laser desorption/ionization(MALDI)protein fingerprinting,top-down proteomics and bottom-up proteomics,in the profiling of bacterial protein composition.It was revealed that bottom-up proteomics provided the highest protein coverage and exhibited the greatest protein profile overlap between bacterial species.In contrast,MALDI protein fingerprinting demonstrated superior detection reproducibility and effectiveness in distinguishing between bacterial species.Although top-down proteomics identified fewer proteins than bottom-up approach,it complemented MALDI fingerprinting in the discovery of bacterial protein markers,both favoring abundant,stable,and hydrophilic bacterial ribosomal proteins.This study represents the most systematic and comprehensive comparison of mass spectrometry-based protein profiling methodologies to date.It provides valuable guidelines for the selection of appropriate profiling strategies for specific analytical purposes.This will facilitate studies across various fields,including infection diagnosis,antimicrobial resistance detection and pharmaceutical target discovery. 展开更多
关键词 BACTERIA Protein profiling Mass spectrometry
在线阅读 下载PDF
基于部分调用图的线程敏感Profiling技术 被引量:1
2
作者 刘弢 吴承勇 张兆庆 《计算机工程》 CAS CSCD 北大核心 2008年第10期30-32,共3页
Profiling技术能提供程序实际执行时的相关信息。在动态编译环境中,Profiling的运行时开销导致难以收集较为复杂的运行时信息。该文提出一种基于部分调用图的Profiling技术,在收集多线程程序中线程相关的各种执行信息时,能有效减少运行... Profiling技术能提供程序实际执行时的相关信息。在动态编译环境中,Profiling的运行时开销导致难以收集较为复杂的运行时信息。该文提出一种基于部分调用图的Profiling技术,在收集多线程程序中线程相关的各种执行信息时,能有效减少运行时开销。在开放源码的虚拟机上实现了该Profiling技术。实验表明,其运行时开销只有原来的2%-4%。 展开更多
关键词 profiling技术 在线profiling 运行时环境
在线阅读 下载PDF
基于OPT Cache替换Profiling的Cache提示生成
3
作者 田兴彦 黄春 陈火旺 《计算机工程》 CAS CSCD 北大核心 2005年第20期85-87,共3页
提出了一个基于最优Cache替换(OPT)Profiling的静态Cache提示生成方法,并通过模拟SPEC2000Int测试程序,对该方法与LRUCache替换策略进行了性能比较。
关键词 Cache提示 profiling优化 OPT Cache替换
在线阅读 下载PDF
指导cache静态划分的程序性能profiling优化技术 被引量:3
4
作者 贾耀仓 武成岗 张兆庆 《计算机研究与发展》 EI CSCD 北大核心 2012年第1期93-102,共10页
对于共享cache的多核处理器,如何管理好各个核对cache的利用,对于充分发挥多核处理器性能是很关键的问题.目前采用的cache替换方法程序间会出现性能干扰,cache静态划分技术则是通过为同时运行的程序分配不同的空间来解决性能干扰问题.... 对于共享cache的多核处理器,如何管理好各个核对cache的利用,对于充分发挥多核处理器性能是很关键的问题.目前采用的cache替换方法程序间会出现性能干扰,cache静态划分技术则是通过为同时运行的程序分配不同的空间来解决性能干扰问题.为了给程序分配合适大小的cache空间,需要对程序进行性能profiling,即事先多遍运行收集程序在各种cache容量下的性能数据,这种性能profiling方法开销巨大,影响实用.为了解决性能profiling需要多遍运行程序的问题,提出了只需单遍运行的程序性能profiling优化技术.该技术利用在线的phase分析技术识别程序的运行阶段,避免对相同阶段的重复profiling;同时分析程序各phase的性能同cache容量变化的关系趋势,对于性能不敏感的容量变化则不进行profiling,降低开销.在程序运行结束后通过程序各phase在cache各种容量下的性能来估计程序在各容量下的整体性能,以指导cache静态划分.实验表明,该技术的开销仅为7%,而该方法指导的cache划分比未划分时有8%的性能改进,同多遍运行的程序性能profiling指导的cache划分性能相比仅有1%的下降. 展开更多
关键词 多核 CACHE划分 页着色 性能profiling phase分析
在线阅读 下载PDF
Cache Profiling技术 被引量:2
5
作者 周谦 冯晓兵 张兆庆 《计算机工程》 EI CAS CSCD 北大核心 2006年第13期47-48,共2页
如何减少和隐藏cache失效的延迟,是人们关注的热点。编译器为了得到cache访问命中的情况,往往使用模拟器去跑一遍来得到结果,这样的速度很慢。为了克服以上缺点,提出了在编译器中作cache profiling来获取cache访问的信息。类似于value p... 如何减少和隐藏cache失效的延迟,是人们关注的热点。编译器为了得到cache访问命中的情况,往往使用模拟器去跑一遍来得到结果,这样的速度很慢。为了克服以上缺点,提出了在编译器中作cache profiling来获取cache访问的信息。类似于value profiling和strideprofiling,cache profiling对访存指令作插装,可以有效地提高速度,并且只需要编译器的支持即可。Cache profiling获得的信息可以用来改进指令调度、软件预取、生成cache hint和辅助线程等。 展开更多
关键词 profiling CACHE profiling CACHE HINT 编译器
在线阅读 下载PDF
基于动态profiling技术的流水粒度调优 被引量:2
6
作者 马琳 陈莉 冯晓兵 《计算机研究与发展》 EI CSCD 北大核心 2005年第6期1065-1072,共8页
结点间流水是解决数据分布和计算分割不一致时的一种重要的并行发掘技术.结点间流水通过计算与通信的重叠获得并行度.精确的流水粒度是获得良好的流水性能的关键.流水分块取决于很多因素,如程序规模、程序的访问模式、结点规模、结点的... 结点间流水是解决数据分布和计算分割不一致时的一种重要的并行发掘技术.结点间流水通过计算与通信的重叠获得并行度.精确的流水粒度是获得良好的流水性能的关键.流水分块取决于很多因素,如程序规模、程序的访问模式、结点规模、结点的计算能力和存储体系、通信系统的性能、通信库开销等等.提出了动态profiling方式并实现在流水粒度的推导中,运行时信息收集部分典型分块,结合代价模型推导流水粒度,该模型考虑局部性优化;探索如何减少插桩执行的开销的同时保证代价模型的精度.实验证明,这种方式有更好的适应性,能获得较好的流水并行. 展开更多
关键词 结点间流水 动态profiling技术 循环变换
在线阅读 下载PDF
cache profiling信息指导的软件流水 被引量:1
7
作者 周谦 冯晓兵 张兆庆 《计算机研究与发展》 EI CSCD 北大核心 2008年第5期834-840,共7页
软件流水是一种重要的指令调度技术,它通过同时执行来自不同循环迭代的指令来加快循环的执行时间.随着处理器速度和访存速度差距越拉越大,访存指令尤其是cache miss的访存指令日益成为系统性能提高的瓶颈.由于这些指令的延迟不是固定的... 软件流水是一种重要的指令调度技术,它通过同时执行来自不同循环迭代的指令来加快循环的执行时间.随着处理器速度和访存速度差距越拉越大,访存指令尤其是cache miss的访存指令日益成为系统性能提高的瓶颈.由于这些指令的延迟不是固定的,如何在软件流水中预测并掩盖这些访存指令的延迟是非常重要的.与前人预测访存延迟的方法不同,引入cache profiling技术,通过动态收集到profile信息来预测访存延迟,并进行适当的调度.当增加模调度循环中的访存指令的延迟时,启动间隔也会随之增大,导致性能不会随之上升.CSMS算法和FLMS算法在尽量不增大启动间隔的情况下,改变访存指令的延迟.改进了CSMS算法和FLMS算法,根据cache profiling的信息来改变访存延迟,所以比前人的方法更为准确.实验表明,新方法可以有效地提高程序性能,对SPEC2000测试程序平均性能提高1%左右,个别例子的性能改进高达11%. 展开更多
关键词 软件流水 模调度 CACHE profiling 访存延迟 高性能计算
在线阅读 下载PDF
基于edge profiling的循环运行时信息分析方法
8
作者 牛晓霞 吴艳霞 +2 位作者 顾国昌 张博为 李静梅 《计算机工程与应用》 CSCD 2012年第29期8-12,50,共6页
应用程序中循环部分往往是计算密集型应用的主要工作负载,随着基于FPGA的可重构计算系统的出现,循环的静态分析技术已不能满足可重构计算系统根据程序当前行为模式进行特定优化的要求。针对现有的程序动态分析技术无法直接获取循环动态... 应用程序中循环部分往往是计算密集型应用的主要工作负载,随着基于FPGA的可重构计算系统的出现,循环的静态分析技术已不能满足可重构计算系统根据程序当前行为模式进行特定优化的要求。针对现有的程序动态分析技术无法直接获取循环动态信息的问题,提出一种循环信息分析算法,根据支配关系在控制流图中识别循环,通过edge profiling的结果分析计算得到循环调用次数、循环平均迭代次数及循环运行时间等关键信息,并在LLVM(Low Level Virtual Machine)平台上实现该算法。实验结果表明,该算法能够自动识别所有循环结构,并对循环部分进行精确分析,分析结果能够为可重构计算系统待加速计算密集型循环的选择提供较全面、精确的信息支持,对程序员进行可重构系统中软硬件划分技术的研究具有重要作用。 展开更多
关键词 计算机系统结构 循环运行时信息 EDGE profiling
在线阅读 下载PDF
Characterization of the 19 Novel Cotton FLA Genes and Their Expression Profiling in Fiber Development and in Response to Phytohormones and Salt Stress 被引量:12
9
作者 HUANG Geng-qing,XU Wen-liang,GONG Si-ying,WANG Xiu-lan,LI Xue-bao(College of Life Sciences,Huazhong Normal University,Wuhan 430079,China) 《棉花学报》 CSCD 北大核心 2008年第S1期55-,共1页
Fasciclin-like arabinogalactan proteins(FLAs),a subclass of arabinogalactan proteins(AGPs),are usually involved in cell development in plants.To investigate the expression profiling as well
关键词 FLA Characterization of the 19 Novel Cotton FLA Genes and Their Expression profiling in Fiber Development and in Response to Phytohormones and Salt Stress
在线阅读 下载PDF
Expression Profiling Identifies Candidate Genes for Fiber Yield and Quality 被引量:3
10
作者 LLEWELLYN D J MACHADO A +1 位作者 AI-GHAZI Y DENNIS E S 《棉花学报》 CSCD 北大核心 2008年第S1期9-,共1页
Gene expression profiling at early stages(0~2 DPA) of fiber development in Gossypium hirsutum identified a number of transcription factors which were down regulated in fiberless mutants relative to wild type controls... Gene expression profiling at early stages(0~2 DPA) of fiber development in Gossypium hirsutum identified a number of transcription factors which were down regulated in fiberless mutants relative to wild type controls and which could play a role in controlling early fiber development.Chief among these was GhMYB25,a Mixta-like MYB gene.Transgenic GhMYB25-silenced cotton 展开更多
关键词 GENE ROOT Expression profiling Identifies Candidate Genes for Fiber Yield and Quality
在线阅读 下载PDF
Transcriptome Profiling and Analysis during Cotton Fiber Cell Development
11
作者 ZHU Yu-xian(The National Laboratory of Protein Engineering and Plant Genetic Engineering,College of Life Sciences,Peking University,Beijing 100871,China) 《棉花学报》 CSCD 北大核心 2008年第S1期129-,共1页
In this project,we aim to elucidate the molecular mechanism controlling initiation and elongation of tetraploid Gossypium hirsutum fiber cells by setting up a high throughput custom-designed
关键词 HIGH CELL Transcriptome profiling and Analysis during Cotton Fiber Cell Development
在线阅读 下载PDF
SIGNAL SAMPLING DEPTH-INDUCED SKEW EFFECT IN SIMS DEPTH PROFILING
12
作者 Ye Hongzhen Microelectronics Center, Academia Sinica, P. O. Box: 650, 100010, Beijing Yu Chunfu Shanghai Institute of Testing Technology, 200233, Shanghai 《真空科学与技术学报》 EI CAS CSCD 1992年第Z1期171-174,共4页
The effect of signal sampling depth in SIMS on profile was not reported We have found that the maximum sampling depth in SIMS is considerably bigger than the mean penetration range of primary ions and can skew the pro... The effect of signal sampling depth in SIMS on profile was not reported We have found that the maximum sampling depth in SIMS is considerably bigger than the mean penetration range of primary ions and can skew the profile of secondary ion counts for implanted samples on the more deeper direction from the surface. The effect of maximum sampling depth is true not only for implanted samples but also for the samples in the middle of which there is an other impurity-rich layer. The action principle of signal sampling depth effect and the method of decreasing the error produced by the effect are discussed in this 展开更多
关键词 SIMS SIGNAL SAMPLING DEPTH-INDUCED SKEW EFFECT IN SIMS DEPTH profiling
在线阅读 下载PDF
ELECTRICAL STRUCTURES OF THE CRUST AND UPPER MANTLE OF TIBETAN PLATEAU FROM MAGNETOTELLURIC PROFILING OF INDEPTH-MT 被引量:2
13
作者 Wei Wenbo 1, Tan Handong 1, Jin Sheng 1, Deng Ming 1, Martyn Unsworth 2, Shenghui Li 2, Paul Bedroson 2, John Booker 2,Alan Jones 3 2 University of Washington, USA 3 Geolo 《地学前缘》 EI CAS CSCD 2000年第S1期319-319,共1页
To extend our successful Magnetotelluric(MT) experiments in the area from Yadong to Bamocuo in 1995 (Chen et al., 1996), two new Magnetotelluric(MT)experiments have been carried out along two main profiles in the cent... To extend our successful Magnetotelluric(MT) experiments in the area from Yadong to Bamocuo in 1995 (Chen et al., 1996), two new Magnetotelluric(MT)experiments have been carried out along two main profiles in the central and Northern Tibetan Plateau in the summer of 1998 and 1999. While the 1995 MT work mainly focused on the study of the electrical structure of the Yarlung\|Zangbo River Suture , the 1998 and 1999 experiments have been designed with following purpose:(1) Study whether partially molten layer widely exists in the crust of the central and northern Tibet.(2) Study the electrical structures of crust and upper mantle in central and northern Tibet which may relate to the attenuated Shear Seismic waves.(3) Study the detail electrical structures of Bangong\|Nujiang Suture and Jinsha Suture.In 1998, the MT team (China University of Geosciences, University of Washington and Geological Survey of Canada) recorded MT data along the Tibet 500 Line which extends about three hundred and eighty kilometers from Deqing to Longweicuo. We used LIMS system to record the long period(20~20000s) MT data at twenty\|six sites and used MT24 to record broadband(320Hz,2000s) MT data at fifty\|eight sites. 展开更多
关键词 MAGNETOTELLURIC profile SUTURE TIBET
在线阅读 下载PDF
Wind Measurement with a Wind Profiling Radar
14
作者 Qi Rundong, Huang Changcheng and Tian Wenbin Beijing Institute of Radio Measurement, P. O. Box 3923, Beijing 100854, China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1991年第1期81-88,共8页
The first troposphere wind profiling radar in China has been in operation. The paper describes the radar parameters and characteristics with some experimental results presented.
关键词 Pulsed Doppler radar Wind profiler Wind measurement.
在线阅读 下载PDF
带固定效应半变系数面板数据模型的约束估计
15
作者 何帮强 赵瑞 《工程数学学报》 北大核心 2025年第5期949-962,共14页
研究了带固定效应的半变系数面板数据模型在线性约束下的统计推断问题。该模型利用固定效应控制个体间时不变差异,同时通过变系数函数捕捉协变量与响应变量非线性关联,克服了传统参数模型灵活性不足与非参数模型“维数灾祸”的局限,并... 研究了带固定效应的半变系数面板数据模型在线性约束下的统计推断问题。该模型利用固定效应控制个体间时不变差异,同时通过变系数函数捕捉协变量与响应变量非线性关联,克服了传统参数模型灵活性不足与非参数模型“维数灾祸”的局限,并为经济结构假设、政策干预条件等实际常见的约束提供理论支持。研究首先基于约束Profile最小二乘法构建参数和非参数光滑系数函数的无约束估计量;其次,通过引入个体虚拟变量分离固定效应,消除其对被解释变量的影响;最后,结合线性约束条件,利用拉格朗日乘子法构造出参数、非参数函数及误差方差的约束估计量。在正则条件下,严格证明了这三个约束估计量均具渐近正态性。蒙特卡洛模拟表明:有限样本下约束估计显著提升了参数估计精度,且当固定效应与协变量相关性增强时,其稳健性优势更为显著。 展开更多
关键词 半变系数面板数据模型 约束条件 Profile最小二乘法 固定效应
在线阅读 下载PDF
消费者评价方法在敏感肌适用面霜中的应用
16
作者 齐荣 程党党 《日用化学工业(中英文)》 北大核心 2025年第4期464-471,共8页
为了探究敏感肌适用面霜的偏好方向,筛选市售5款人气敏感肌适用面霜产品,通过9点喜好标度、Rate-all-that-apply(RATA)、Ideal profile method(IPM)等多种消费者研究方法从产品喜好度、理想产品、产品特征和情绪赋值等方面进行消费者测... 为了探究敏感肌适用面霜的偏好方向,筛选市售5款人气敏感肌适用面霜产品,通过9点喜好标度、Rate-all-that-apply(RATA)、Ideal profile method(IPM)等多种消费者研究方法从产品喜好度、理想产品、产品特征和情绪赋值等方面进行消费者测试,从多个维度对测试产品进行分析探究。结果表明,契合调查目的从而针对性地选择适用的消费者调查方法并且通过多种方法的结合应用,可以获得较为完整的敏感肌适用面霜开发思路。另外相比常规的消费者喜好度研究,当下消费者较为关注的产品概念、情绪赋值方面的评价也体现出较好的应用价值。 展开更多
关键词 敏感肌适用面霜 消费者喜好度 Ideal profile method(IPM) Rate-all-that-apply(RATA) 情绪护肤
在线阅读 下载PDF
Grain morphology and plasticizing mechanism of AZ31 magnesium alloy curved profiles by staggered extrusion
17
作者 CHEN Zi-yu LI Feng +2 位作者 LI Yuan-qi LI Chao SUN Lu 《Journal of Central South University》 2025年第2期319-331,共13页
Traditional manufacturing processes for lightweight curved profiles are often associated with lengthy procedures,high costs,low efficiency,and high energy consumption.In order to solve this problem,a new staggered ext... Traditional manufacturing processes for lightweight curved profiles are often associated with lengthy procedures,high costs,low efficiency,and high energy consumption.In order to solve this problem,a new staggered extrusion(SE)process was used to form the curved profile of AZ31 magnesium alloy in this paper.The study investigates the mapping relationship between the curvature,microstructure,and mechanical properties of the formed profiles by using different eccentricities of the die.Scanning electron microscopy(SEM)and electron backscatter diffraction techniques are employed to examine the effects of different eccentricity values(e)on grain morphology,recrystallization mechanisms,texture,and Schmid factors of the products.The results demonstrate that the staggered extrusion method promotes the deep refinement of grain size in the extruded products,with an average grain size of only 15%of the original billet,reaching 12.28μm.The tensile strength and elongation of the curved profiles after extrusion under the eccentricity value of 10 mm,20 mm and 30 mm are significantly higher than those of the billet,with the tensile strength is increased to 250,270,235 MPa,and the engineering strain elongation increased to 10.5%,12.1%,15.9%.This indicates that staggered extrusion enables curvature control of the profiles while improving their strength. 展开更多
关键词 staggered extrusion ECCENTRICITY curved profiles MICROSTRUCTURE mechanical properties
在线阅读 下载PDF
Research on Collaborative Filtering Recommendation Algorithm Based on Improved User Portraits 被引量:3
18
作者 HOU Meng WANG Guo-peng +2 位作者 SONG Li-zhe WANG Hao-yue SI Zhan-jun 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第6期117-123,134,共8页
With the arrival of the big data era,the phenomenon of information overload is becoming increasingly severe.In response to the common issue of sparse user rating matrices in recommendation systems,a collaborative filt... With the arrival of the big data era,the phenomenon of information overload is becoming increasingly severe.In response to the common issue of sparse user rating matrices in recommendation systems,a collaborative filtering recommendation algorithm was proposed based on improved user profiles in this study.Firstly,a profile labeling system was constructed based on user characteristics.This study proposed that user profile labels should be created using basic user information and basic item information,in order to construct multidimensional user profiles.TF-IDF algorithm was used to determine the weights of user-item feature labels.Secondly,user similarity was calculated by weighting both profile-based collaborative filtering and user-based collaborative filtering algorithms,and the final user similarity was obtained by harmonizing these weights.Finally,personalized recommendations were generated using Top-N method.Validation with the MovieLens-1M dataset revealed that this algorithm enhances both recommendation Precision and Recall compared to single-method approaches(recommendation algorithm based on user portrait and user-based collaborative filtering algorithm). 展开更多
关键词 Collaborative filtering User profiling Recommender system SIMILARITY
在线阅读 下载PDF
Research on User Profile Construction Method Based on Improved TF-IDF Algorithm
19
作者 SHAO Ze-ming LI Yu-ang +4 位作者 YANG Ke WANG Guo-peng LIU Xing-guo CHEN Han-ning SI Zhan-jun 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第6期110-116,共7页
In the data-driven era of the internet and business environments,constructing accurate user profiles is paramount for personalized user understanding and classification.The traditional TF-IDF algorithm has some limita... In the data-driven era of the internet and business environments,constructing accurate user profiles is paramount for personalized user understanding and classification.The traditional TF-IDF algorithm has some limitations when evaluating the impact of words on classification results.Consequently,an improved TF-IDF-K algorithm was introduced in this study,which included an equalization factor,aimed at constructing user profiles by processing and analyzing user search records.Through the training and prediction capabilities of a Support Vector Machine(SVM),it enabled the prediction of user demographic attributes.The experimental results demonstrated that the TF-IDF-K algorithm has achieved a significant improvement in classification accuracy and reliability. 展开更多
关键词 TF-IDF-K algorithm User profiling Equalization factor SVM
在线阅读 下载PDF
用VSP资料求取吸收参数方法的研究 被引量:1
20
作者 王彦春 董敏煜 《石油地球物理勘探》 EI CSCD 北大核心 1990年第6期662-675,761,共15页
VSP 资料的直达下行波能量强,信噪比高,为求取吸收参数提供了有利条件。然而,现有的一些求取吸收参数的方法均不能有效地压制上行波及短程多次下行波的影响,因此利用下行波求得的吸收参数精度不高。相比而言,“振幅谱比法”应用较广,而... VSP 资料的直达下行波能量强,信噪比高,为求取吸收参数提供了有利条件。然而,现有的一些求取吸收参数的方法均不能有效地压制上行波及短程多次下行波的影响,因此利用下行波求得的吸收参数精度不高。相比而言,“振幅谱比法”应用较广,而且不受震源能量变化的影响。本文对振幅谱比法作了修正,即利用声波、密度测井曲线构成的反射系数序列对直达下行波的非弹性吸收的振幅进行校正,以消除上行波的干涉和短程多次波的影响,然后再用振幅谱比法求品质因数。这种改进方法称“校后谱比法”。在有高质量的声波、密度测井资料时,使用 VSP 资料可比较准确地求取介质内的吸收参数,并可改善吸收参数的空间分辨率。通过在 SVSP 资料上试算表明,改进的方法是行之有效的。 展开更多
关键词 absorption parameter VERTICAL SEISMIC profiling (VSP) synthetic VERTICAL SEISMIC profiling(SVSP) AMPLITUDE spectrum ratio method
在线阅读 下载PDF
上一页 1 2 9 下一页 到第
使用帮助 返回顶部