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A maximum margin clustering algorithm based on indefinite kernels
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作者 Hui XUE Sen LI +1 位作者 Xiaohong CHEN Yunyun WANG 《中国计算机科学前沿:英文版》 SCIE EI CSCD 2019年第4期813-827,共15页
Indefinite kernels have attracted more and more attentions in machine learning due to its wider application scope than usual positive definite kernels. However, the research about indefinite kernel clustering is relat... Indefinite kernels have attracted more and more attentions in machine learning due to its wider application scope than usual positive definite kernels. However, the research about indefinite kernel clustering is relatively scarce. Furthermore, existing clustering methods are mainly designed based on positive definite kernels which are incapable in indefinite kernel scenarios. In this paper, we propose a novel indefinite kernel clustering algorithm termed as indefinite kernel maximum margin clustering (IKMMC) based on the state-of-the-art maximum margin clustering (MMC) model. IKMMC tries to find a proxy positive definite kernel to approximate the original indefinite one and thus embeds a new F-norm regularizer in the objective function to measure the diversity of the two kernels, which can be further optimized by an iterative approach. Concretely, at each iteration, given a set of initial class labels, IKMMC firstly transforms the clustering problem into a classification one solved by indefinite kernel support vector machine (IKSVM) with an extra class balance constraint and then the obtained prediction labels will be used as the new input class labels at next iteration until the error rate of prediction is smaller than a prespecified tolerance. Finally, IKMMC utilizes the prediction labels at the last iteration as the expected indices of clusters.Moreover, we further extend IKMMC from binary clustering problems to more complex multi-class scenarios. Experimental results have shown the superiority of our algorithms. 展开更多
关键词 INDEFINITE KERNEL MAXIMUM MARGIN CLUSTERING support vector machine KERNEL method
几类特殊有向循环图的核
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作者 任秀秀 杨卫华 《数学进展》 CSCD 北大核心 2019年第2期137-144,共8页
有向图D=(V,A)的核K是顶点集V的一个子集,其中K中任意两点在D中均不相邻,并且对V\K中任意一个点v,都存在K中的一个点u,使得(v,u)是D中的一条弧.一般有向图核的存在问题是NP-完全的.Bang-Jensen和Gutin在他们的著作[Digraphs:Theory, Alg... 有向图D=(V,A)的核K是顶点集V的一个子集,其中K中任意两点在D中均不相邻,并且对V\K中任意一个点v,都存在K中的一个点u,使得(v,u)是D中的一条弧.一般有向图核的存在问题是NP-完全的.Bang-Jensen和Gutin在他们的著作[Digraphs:Theory, Algorithms and Applications, London:Springer-Verlag, 2000]中提出公开问题(Problem 12.3.5):刻画有向循环图核存在性.本文研究了几类特殊有向循环图核的存在问题,并给出了Duchet核猜想(对任意一个不是有向奇圈的无核有向图,都存在一条弧,使得删除这条弧所得到的图仍然是无核的)的一类反例. 展开更多
关键词 有向图 循环图 Duchet核猜想
Modeling turbulent transport effects on kernel formation and ?ame propagation in an ignition process
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作者 Linghan KONG Zhuyin REN Lingyun HOU 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第4期895-905,共11页
Reliable relighting is crucial for advanced low-emission aero-engine combustors. For forced ignition under highly-turbulent conditions, eddies of sizes being smaller than the flame kernel can affect its formation thro... Reliable relighting is crucial for advanced low-emission aero-engine combustors. For forced ignition under highly-turbulent conditions, eddies of sizes being smaller than the flame kernel can affect its formation through penetrating and modifying the kernel structure. In this study, a one-dimensional model for small-scale turbulence on kernel formation is developed through the incorporation of turbulence-induced diffusion in governing equations. With given flow conditions,the spatial and time-dependent turbulent diffusivity is modeled using the idea of residual eddy viscosity. One-dimensional spherical flames of premixed pre-vaporized n-dodecane/air mixtures under high-altitude conditions are simulated to investigate the effects of turbulence. It is revealed that the range of the equivalence ratio for successful turbulent ignition is much narrower than that for laminar ignition. The range decreases with an increased turbulent intensity, and this effect is more pronounced for a low spark energy. In addition, turbulent transport has more pronounced effects on rich mixtures. An analysis on energy budget and species profiles shows that turbulence-induced diffusion enhances the heat loss at the very beginning of the kernel formation process that could lead to ignition failure. After the flame kernel is established, turbulent transport broadens the flame front, enhances the heat release rate, and thereafter increases the flame propagation speed. 展开更多
关键词 FLAME KERNEL FLAME PROPAGATION HIGH-ALTITUDE ignition KERNEL FORMATION probability Turbulence-induced diffusion
多核学习SVM在发动机故障诊断上的应用 预览
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作者 曹惠玲 薛成 薛鹏 《机械设计与制造》 北大核心 2019年第5期1-4,9共5页
为了从小样本的发动机性能参数故障数据中提取故障信息,准确而快速的识别故障数据,支持向量机具备的诸多优点使其逐步的应用到发动机的故障诊断中。目前,已有不少利用支持向量机进行发动机故障诊断的研究,但对核函数的选用大多使用单一... 为了从小样本的发动机性能参数故障数据中提取故障信息,准确而快速的识别故障数据,支持向量机具备的诸多优点使其逐步的应用到发动机的故障诊断中。目前,已有不少利用支持向量机进行发动机故障诊断的研究,但对核函数的选用大多使用单一核函数对数据进行训练,在没有先验的情况下,往往不容易选择出最优的核函数。通过对核函数的研究,提出将基于多核学习构建的组合核函数作为支持向量机新的映射函数,通过故障实例演示了多核学习SVM在发动机故障诊断上的应用,说明了组合核函数的构建方法和相比于单一核函数的优越性。 展开更多
关键词 故障诊断 支持向量机 核函数 多核学习 组合核函数
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An effi cient scheme for multi-GPU TTI reverse time migration 预览
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作者 Liu Guo-Feng Meng Xiao-Hong +1 位作者 Yu Zhen-Jiang Liu Ding-Jin 《应用地球物理:英文版》 SCIE CSCD 2019年第1期56-63,共8页
Reverse time migration (RTM) is an indispensable but computationally intensive seismic exploration technique. Graphics processing units (GPUs) by NVIDIA■offer the option for parallel computations and speed improvemen... Reverse time migration (RTM) is an indispensable but computationally intensive seismic exploration technique. Graphics processing units (GPUs) by NVIDIA■offer the option for parallel computations and speed improvements in such high-density processes. With increasing seismic imaging space, the problems associated with multi-GPU techniques need to be addressed. We propose an efficient scheme for multi-GPU programming based on the features of the compute-unified device Architecture (CUDA) using GPU hardware, including concurrent kernel execution, CUDA streams, and peer-to-peer (P2P) communication between the different GPUs. In addition, by adjusting the computing time for imaging during RTM, the data communication times between GPUs become negligible. This means that the overall computation effi ciency improves linearly, as the number of GPUs increases. We introduce the multi-GPU scheme by using the acoustic wave propagation and then describe the implementation of RTM in tilted transversely isotropic (TTI) media. Next, we compare the multi-GPU and the unifi ed memory schemes. The results suggest that the proposed multi- GPU scheme is superior and, with increasing number of GPUs, the computational effi ciency improves linearly. 展开更多
关键词 multi-GPU KERNEL PEER-TO-PEER FORWARD MODELING TTI RTM
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Simulation of drop breakage in liquid–liquid system by coupling of CFD and PBM: Comparison of breakage kernels and effects of agitator configurations
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作者 Rui Xie Jun Li +2 位作者 Yang Jin Da Zou Ming Chen 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2019年第5期1001-1014,共14页
This work focuses on drop breakage for liquid-liquid system with an adoption of numerical simulation by using computational fluid dynamics and population balance model (PBM) coupled with two-fluid model (TFM). Two dif... This work focuses on drop breakage for liquid-liquid system with an adoption of numerical simulation by using computational fluid dynamics and population balance model (PBM) coupled with two-fluid model (TFM). Two different breakage kernels based on identical breakage mechanism but different descriptions of breaking time are take n into account in this work. Eight cases corresp on ding to distinct configurations of agitator are carried out to validate numerical predictions, namely agitators with different porosity and hole diameters, respectively implemented in Cases 1 to 5 and Cases 6 to 8. The results are compared with experimental data for testing the applicability of both kernels. Simulations are implemented, in this work, with an approach of class method for the solution of population balance model by the special-purpose computational fluid dynamics solver Fluent 16.1 based on finite volume method, and the grids used for meshing the solution domain are accomplished in a commercial software Gambit 2.4.6. The effects of configurations of agitator corresponding to different parameters mentioned above on final Sauter mean diameter are equally concentrated in this work. Analysis of both kernels and comparisons with experimental results reveal that, the second kernel has more decent agreement with experiments, and the results of investigations on effects of agitator configurations show that the in fluences of these parameters on Sauter mean diameter are marginal, but appropriate porosity and hole diameter are actually able to decrease Sauter mean diameter. These outcomes allow us to draw general conclusions and help investigate performances of liquid-liquid system. 展开更多
关键词 Stirred vessel LIQUID-LIQUID system Computational fluid dynamics Population balance model BREAKAGE kernel AGITATOR configuration
竹柏种仁油脂成分及其抗氧化活性分析 预览
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作者 徐华 杨德孟 +3 位作者 楼乔明 张进杰 杨文鸽 徐大伦 《中国粮油学报》 EI CAS CSCD 北大核心 2019年第2期87-92,共6页
采用5种方法对竹柏种仁油脂进行提取,并通过核磁共振和气相色谱-质谱技术分别对其油脂成分和脂肪酸组成进行分析,同时采用DPPH自由基清除法和羟基自由基清除法对竹柏种仁油脂的抗氧化活性进行研究。结果表明,5种方法对竹柏种仁油脂的提... 采用5种方法对竹柏种仁油脂进行提取,并通过核磁共振和气相色谱-质谱技术分别对其油脂成分和脂肪酸组成进行分析,同时采用DPPH自由基清除法和羟基自由基清除法对竹柏种仁油脂的抗氧化活性进行研究。结果表明,5种方法对竹柏种仁油脂的提取率存在显著差异(P <0.05),其中Folch法的提取率最高,为53. 81%。竹柏种仁油脂以甘油三酯为主,磷脂、游离脂肪酸和甾醇含量极低。竹柏种仁油脂经2 mol/L KOH-甲醇溶液室温衍生3 min,甲酯转化率即达99. 80%;且其脂肪酸以油酸(18. 65%)、亚油酸(43.49%)和花生烯酸(30.65%)为主,不饱和脂肪酸含量高达90%以上。竹柏种仁油脂对DPPH自由基和羟基自由基的IC50分别为3.36 mg/mL和0. 38 mg/mL,表明竹柏种仁油脂具有较好的抗氧化能力,可作为健康植物油脂进行开发利用,具有良好的开发潜力和应用前景。本研究为竹柏种仁油脂的提取、成分分析和抗氧化活性研究提供了一定的参考。 展开更多
关键词 竹柏 种仁 油脂 甲酯化 脂肪酸 抗氧化活性
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Image Blind Deblurring Using an Adaptive Patch Prior
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作者 Yongde Guo Hongbing Ma 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第2期238-248,共11页
Image blind deblurring uses an estimated blur kernel to obtain an optimal restored original image with sharp features from a degraded image with blur and noise artifacts.This method,however,functions on the premise th... Image blind deblurring uses an estimated blur kernel to obtain an optimal restored original image with sharp features from a degraded image with blur and noise artifacts.This method,however,functions on the premise that the kernel is estimated accurately,in this work,we propose an adaptive patch prior for improving the accuracy of kernel estimation.Our proposed prior is based on local patch statistics and can rebuild low-level features, such as edges,corners,and junctions,to guide edge and texture sharpening for blur estimation.Our prior is a nonparametric model,and its adaptive computation relies on internal patch information.Moreover,heuristic filters and external image knowledge are not used in our prior.Our method for the reconstruction of salient step edges in a blurry patch can reduce noise and over-sharpening artifacts.Experiments on two popular datasets and natural images demonstrate that the kernel estimation performance of our method is superior to that of other state-of-the-art methods. 展开更多
关键词 BLIND DEBLURRING ADAPTIVE PATCH prior KERNEL estimation low-level features INTERNAL PATCH information
Directional Analysis of Urban Expansion Based on Sub-pixel and Regional Scale: A Case Study of Main Districts in Guangzhou, China 预览
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作者 ZHAO Yi ZHONG Kaiwen +2 位作者 XU Jianhui SUN Caige WANG Yunpeng 《中国地理科学:英文版》 SCIE CSCD 2019年第4期652-666,共15页
Multi-scale data have had a wide-ranging level of performance in the area of urban change monitoring. Herein we investigate the correlation between the impervious surface fraction(ISF) and the Defense Meteorological S... Multi-scale data have had a wide-ranging level of performance in the area of urban change monitoring. Herein we investigate the correlation between the impervious surface fraction(ISF) and the Defense Meteorological Satellite Program/Operational Linescan System(DMSP/OLS) nighttime stable light(NTL) data with respect to the urban expansion in the main districts of Guangzhou. Landsat 5 Thematic Mapper and Landsat 8 Operational Land Image(OLI) data from 1988 to 2015 were used to extract the ISF using the linear spectral mixture analysis model and normal difference build-up index at the sub-pixel scale. DMSP/OLS NTL data from 1992 to 2013 were calibrated to illustrate the urban nighttime light conditions at the regional scale. Urban expansion directions were identified by statistics and kernel density analysis for the ISF study area at the sub-pixel scale. In addition, the correlation between the ISF and DMSP/OLS NTL data were illustrated by linear regression analysis. Furthermore, Profile Graph in ArcGIS was employed to illustrate the urban expansion from the differences in correlation in different directions. The conclusions are as follows: 1) The impervious surface(IS)in the study area has expanded to the northeast and the east, starting with the old urban zones, and the high-density IS area has increased by321.14 km~2. 2) The linear regression analysis reveals a positive correlation between the ISF and the DMSP/OLS NTL data. The multi-scale data changes are consistent with the actual urban planning of Guangzhou. 3) The DMSP/OLS NTL data overestimate the urban extent because of its saturation and blooming effects, causing its correlation with ISF to decrease. The pattern of urban expansion influences the saturation and blooming effects of the DMSP/OLS NTL data. 展开更多
关键词 impervious surface FRACTION linear spectral mixture ANALYSIS NIGHTTIME light kernel density profile graph
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格序代数自同态核性质研究概论 预览
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作者 方捷 《广东技术师范学院学报》 2019年第3期1-5,共5页
称代数A上的一个自同态是强自同态,如果它与A的每个同余都相容.如果除泛同余关系外,A的每个同余都是一个(强)自同态的核,则称A有(强)自同态核性质.本文概述了具有自同态核或强自同态核性质的格序代数的结构定理,诸如deMorgan代数,MS-代... 称代数A上的一个自同态是强自同态,如果它与A的每个同余都相容.如果除泛同余关系外,A的每个同余都是一个(强)自同态的核,则称A有(强)自同态核性质.本文概述了具有自同态核或强自同态核性质的格序代数的结构定理,诸如deMorgan代数,MS-代数,双重MS-代数,p-代数和双重p-代数等. 展开更多
关键词 格序代数 自同态
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MTX操作系统内核与启动流程分析 预览
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作者 任振强 《信息技术与网络安全》 2019年第2期50-54,共5页
通过研究系统从启动到用户程序运行的完整过程,分析了MTX操作系统内核的设计和实现,重点分析了进程的数据结构及进程切换和系统调用的底层代码,总结了系统引导程序的设计要点和单一内存分段式编译模型的特性。
关键词 MTX 实模式 引导程序 内核 进程切换 系统调用
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LKLR: A Local Tangent Space-Alignment Kernel Least-Squares Regression Algorithm
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作者 Chao Tan Genlin Ji 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第4期389-399,共11页
In the fields of machine learning and data mining, label learning is a nascent area of research, and within this paradigm, there is much room for improving multi-label manifold learning algorithms for high-dimensional... In the fields of machine learning and data mining, label learning is a nascent area of research, and within this paradigm, there is much room for improving multi-label manifold learning algorithms for high-dimensional data. Thus far, researchers have experimented with mapping relationships from the feature space to the traditional logical label space(using neighbors in the label space, for example, to predict logical label vectors from the feature space’s manifold structure). Here we combine the feature manifold’s and label space’s local topological structures to reconstruct the label manifold. To achieve this, we use a nonlinear manifold learning algorithm to transform the local topological structure from the feature space to the label space. Our algorithm adopts a regularized leastsquares kernel method to realize the reconstruction process, employing an optimization function to find the best solution. Extensive experiments show that our algorithm significantly improves multi-label manifold learning in terms of learning accuracy and time complexity. 展开更多
关键词 MULTI-LABEL MANIFOLD learning local topological structure REGULARIZED least SQUARES KERNEL method
Experimental investigations on wear properties of Palm kernel reinforced composites for brake pad applications 预览
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作者 Satish Pujari S. Srikiran 《Defence Technology(防务技术)》 CAS CSCD 2019年第3期295-299,共5页
The use of asbestos material is being avoided to manufacture the brake pads as it is harmful and toxic in nature. Further it leads to various health issues like asbestosis, mesothelioma and lung cancers. These brake p... The use of asbestos material is being avoided to manufacture the brake pads as it is harmful and toxic in nature. Further it leads to various health issues like asbestosis, mesothelioma and lung cancers. These brake pads can be replaced by natural fibers like Palm kernel (0-50%), Nile roses (0-15%) and Wheat (0-10%) with additives like aluminum oxide (5%-20%) and graphite powder (10%-35%). Phenolic resin of 35% is utilized as a binder. Particulated Nile roses are used to increase the friction coefficient and wheat powder is used to reduce the wear rate. Aluminum oxide and graphite are abrasive in nature. This helps to make brake pads with high friction co-efficient and less wear rate with low noise pollution. The wear of the proposed composites have been investigated at different speeds. Various tests like wear on pin-ondisc apparatus, hardness on the Rockwell hardness apparatus and oil absorption test have been conducted. Phenolic resin produces good bonding nature to fiber. Thus, Fibers found to have performed palatably among all commercial brake pads. The objective of the research indicates that Palm kernal shell could be a conceivable alternative for asbestos in friction coating materials. 展开更多
关键词 Friction materials PALM KERNEL fiber NILE rose Wheat BRAKE pad WEAR TEST Hardness TEST Oil absorption TEST
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基于核的k-最近邻在水下目标识别中的应用 预览
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作者 严良涛 项晓丽 《应用声学》 CSCD 北大核心 2019年第3期448-451,共4页
针对水下目标特征类型多、非线性强的特点,该文将基于核的 k-最近邻应用于水下目标识别。该方法采用主成分分析对特征矩阵进行降维,利用核函数技巧将降维后的特征映射到高维空间进行 k-最近邻分类识别,并讨论了邻近点个数 k对实验结果... 针对水下目标特征类型多、非线性强的特点,该文将基于核的 k-最近邻应用于水下目标识别。该方法采用主成分分析对特征矩阵进行降维,利用核函数技巧将降维后的特征映射到高维空间进行 k-最近邻分类识别,并讨论了邻近点个数 k对实验结果的影响。实际实验数据验证结果表明:与传统的 k-最近邻和 BP神经网络分类器相比,基于核的 k-最近邻分类器的综合性能更优。 展开更多
关键词 水下目标识别 K-最近邻 主成分分析 核函数
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Quantitative Absolute Continuity of Harmonic Measure and the Dirichlet Problem: A Survey of Recent Progress
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作者 Steve HOFMANN 《数学学报:英文版》 SCIE CSCD 2019年第6期1011-1026,共16页
It is a well-known folklore result that quantitative, scale invariant absolute continuity(more precisely, the weak-A∞ property) of harmonic measure with respect to surface measure, on the boundary of an open set Ω ?... It is a well-known folklore result that quantitative, scale invariant absolute continuity(more precisely, the weak-A∞ property) of harmonic measure with respect to surface measure, on the boundary of an open set Ω ? Rn+1 with Ahlfors–David regular boundary, is equivalent to the solvability of the Dirichlet problem in Ω, with data in Lp (?Ω) for some p < ∞. Drawing an analogy to the famous Wiener criterion, which characterizes the domains in which the classical Dirichlet problem, with continuous boundary data, can be solved, one may seek to characterize the open sets for which Lpsolvability holds, thus allowing for singular boundary data.It has been known for some time that absolute continuity of harmonic measure is closely tied to rectifiability properties of ?Ω, but also that rectifiability alone is not sufficient to guarantee absolute continuity. In this note, we survey recent progress in this area, culminating in a geometric characterization of the weak-A∞ property, and hence of solvability of the Lp Dirichlet problem for some finite p. This characterization, obtained under rather optimal background hypotheses, follows from a combination of the present author’s joint work with Martell, and the work of Azzam, Mourgoglou and Tolsa. 展开更多
关键词 HARMONIC measure POISSON kernel uniform RECTIFIABILITY weak local John condition big pieces of chord-arc DOMAINS CARLESON measures
Influence of contact pressure and sliding speed dependence on the tribological characteristics of an activated carbonepoxy composite derived from palm kernel under dry sliding conditions
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作者 Dayang Nor Fatin MAHMUD Mohd Fadzli Bin ABDOLLAH +2 位作者 Nor Azmmi Bin MASRIPAN NoreffendyTAMALDIN Hilmi AMIRUDDIN 《摩擦(英文版)》 CSCD 2019年第3期227-236,共10页
The objective of this work is to investigate the influence of contact pressure and sliding speed on the coefficient of friction and wear of an activated carbon-epoxy composite derived from palm kernel under dry slidin... The objective of this work is to investigate the influence of contact pressure and sliding speed on the coefficient of friction and wear of an activated carbon-epoxy composite derived from palm kernel under dry sliding conditions.A wear mode map approach was employed to identify the transitions from mild to severe wear of the composite.The dry sliding test was executed by utilizing a ball-on-disc tribometer at different contact pressures and sliding speeds with a constant sliding distance and operating temperature.The results showed that,regardless of the sliding speed,the friction coefficient and wear rate of the composite increased drastically when a critical limit of contact pressure is exceeded.As for the sliding speed,both the friction coefficient and wear rate increased first and thereafter decreased at a higher speed of 500 rpm.A wear mode map is proposed to classify the boundary from mild to severe wear regimes.The predominant wear failures identified include micro-crack,fine grooves,debonding,delamination,debris,broken carbon,and fracture. 展开更多
关键词 ACTIVATED carbon agriculture waste PALM KERNEL friction and WEAR pressure and speed
Estimation in Linear Regression with Laplace Measurement Error Using Tweedie-Type Formula
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作者 SHI Jianhong FENG Jing SONG Weixing 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2019年第4期1211-1230,共20页
Based on a Tweedie-type formula developed under the Laplace distribution,this paper proposes a new bias-corrected estimator of the regression parameters in a simple linear model when the measurement error follows a La... Based on a Tweedie-type formula developed under the Laplace distribution,this paper proposes a new bias-corrected estimator of the regression parameters in a simple linear model when the measurement error follows a Laplace distribution.Large sample properties,including the consistency and the asymptotic normality,are investigated.The finite sample performance of the proposed estimators are evaluated via simulation studies,as well as comparison studies with some existing estimation procedures. 展开更多
关键词 ASYMPTOTIC NORMALITY CONSISTENCY KERNEL ESTIMATOR LAPLACE measurement error simple linear ME model
基于核和认知程度的区间灰数Verhulst预测模型 预览
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作者 李晔 李娟 《河南科学》 2019年第3期477-483,共7页
针对传统的Verhulst模型只能用于对实数序列进行建模预测的问题,将其建模对象扩大到区间灰数序列,构建基于核和认知程度的区间灰数Verhulst预测模型.首先,将区间灰数序列转化为核序列和认知程度序列,实现区间灰数的白化;然后,分别构建... 针对传统的Verhulst模型只能用于对实数序列进行建模预测的问题,将其建模对象扩大到区间灰数序列,构建基于核和认知程度的区间灰数Verhulst预测模型.首先,将区间灰数序列转化为核序列和认知程度序列,实现区间灰数的白化;然后,分别构建核序列和认知程度序列Verhulst模型,并反推区间灰数上下界的表达式;最后,将模型应用于某高层住宅沉降量预测并与其他模型结果对比,实例表明,所建模型的精度较高,具有实用性. 展开更多
关键词 区间灰数 Verhulst预测模型 认知程度
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Spatio-temporal variations of harmful algal blooms along the coast of Guangdong, Southern China during 1980–2016 预览
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作者 LI Li Lü Songhui CEN Jingyi 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第2期535-551,共17页
Harmful algal blooms (HABs) have become a recurring problem, posing severe impacts on marine ecosystems, fisheries, mariculture industry, and even public health. In this study, the geographic information system (GIS) ... Harmful algal blooms (HABs) have become a recurring problem, posing severe impacts on marine ecosystems, fisheries, mariculture industry, and even public health. In this study, the geographic information system (GIS) was utilized to determine spatial and temporal characteristics of HAB events in the coastal waters of Guangdong from 1980–2016. We analyzed distribution patterns and characteristics of HABs by dividing the coast of Guangdong into well-known bays, estuary and coastal waters. Results showed that there were a total of 337 HABs recorded in Guangdong coastal waters. Spatial and temporal distributions varied among diff erent regions. Most HABs occurred in the Mirs Bay, followed by the west coast of Daya Bay, while a few occurred in the west and east coasts of Guangdong but with an increasing trend in the past two decades. HABs occurred mostly in warmer months of March to May in the western coast of Guangdong, March and April in Mirs Bay, April in Zhujiang (Pearl) River estuary, November in eastern coast of Guangdong. For Daya Bay, most HABs were reported between March and September. The most frequently occurring HABs species were Noctiluca scintillans , Phaeocystis globosa , Skeletonema costatum and Scrippsiella trochoidea , occurring mostly in Mirs Bay, western Guangdong coast area, eastern Guangdong coast area and Zhujiang River estuary and Daya Bay, respectively. Ichthyotoxic blooms were more common than toxic blooms, and Heterosigma akashiwo , Chattonella marina , Karenia mikimotoi and P haeocystis globosa were the most common ichthyotoxic species. Our results provide baseline information useful for policy making and management of HABs in the region. 展开更多
关键词 harmful ALGAL BLOOMS GUANGDONG Province distribution GEOGRAPHIC information system (GIS) KERNEL density estimation
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Local Least Product Relative Error Estimation for Varying Coefficient Multiplicative Regression Model
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作者 Da-hai HU 《应用数学学报:英文版》 SCIE CSCD 2019年第2期274-286,共13页
In this article, we consider the varying coefficient multiplicative regression model, which is very useful to model the positive response. The criterion of least product relative error (LPRE) is extended to the varyin... In this article, we consider the varying coefficient multiplicative regression model, which is very useful to model the positive response. The criterion of least product relative error (LPRE) is extended to the varying coefficient multiplicative regression model by kernel smoothing techniques. Consistency and asymptotic normality of the proposed estimator are established. Some numerical simulations are carried out to assess the performance of the proposed estimator. As an illustration, the ethanol data is analyzed. 展开更多
关键词 VARYING COEFFICIENT MODEL MULTIPLICATIVE regression MODEL relative error KERNEL SMOOTHING
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