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Homogenized Daily Mean/Maximum/Minimum Temperature Series for China from 1960-2008 认领 引用 被引量：101
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作者 LI Zhen YAN Zhong-Wei 《Atmospheric and Oceanic Science Letters》 2009年第4期237-243,共7页
Inhomogeneities in the daily mean/maximum/ minimum temperature （Tm/Tmax/Tmin） series from 1960- 2008 at 549 National Standard Stations （NSSs） in China were analyzed by using the Multiple Analysis of Series for Hom... Inhomogeneities in the daily mean/maximum/ minimum temperature （Tm/Tmax/Tmin） series from 1960- 2008 at 549 National Standard Stations （NSSs） in China were analyzed by using the Multiple Analysis of Series for Homogenization （MASH） software package. Typical biases in the dataset were illustrated via the cases of Beijing （B J）, Wutaishan （WT）, Urumqi （UR） and Henan （HN） stations. The homogenized dataset shows a mean warming trend of 0.261/0.193/0.344℃/decade for the annual series of Tm/Tmax/Tmin, slightly smaller than that of the original dataset by 0.006/0.009/0.007℃/decade. However, considerable differences between the adjusted and original datasets were found at the local scale. The adjusted Tmin series shows a significant warming trend almost everywhere for all seasons, while there are a number of stations with an insignificant trend in the original dataset. The adjusted Tm data exhibit significant warming trends annually as well as for the autumn and winter seasons in northern China, and cooling trends only for the summer in the middle reaches of the Yangtze River and parts of central China and for the spring in southwestern China, while the original data show cooling trends at several stations for the annual and seasonal scales in the Qinghai, Shanxi, Hebei, and Xinjiang provinces. The adjusted Tmax data exhibit cooling trends for summers at a number of stations in the mid-lower reaches of the Yangtze and Yellow Rivers and for springs and winters at a few stations in southwestern China, while the original data show cooling trends at three/four stations for the annual/autumn periods in the Qinghai and Yunnan provinces. In general, the number of stations with a cooling trend was much smaller in the adjusted Tm and Tmax dataset than in the original dataset. The cooling trend for summers is mainly due to cooling in August. The results of homogenization using MASH appear to be robust; in particular, different groups of stations with consideration of elevation led to minor effects in the results. 展开更多
关键词 daily mean/maximum/minimum temperature series homogenization China MASH climate trend
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Analysis of Sampling Error Uncertainties and Trends in Maximum and Minimum Temperatures in China 认领 引用 被引量：3
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作者 HUA Wei Samuel S.P.SHEN WANG Huijun 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2014年第2期263-272,共10页
In this paper we report an analysis of sampling error uncertainties in mean maximum and minimum temperatures （Tmax and Tmin） carried out on monthly,seasonal and annual scales,including an examination of homogenized ... In this paper we report an analysis of sampling error uncertainties in mean maximum and minimum temperatures （Tmax and Tmin） carried out on monthly,seasonal and annual scales,including an examination of homogenized and original data collected at 731 meteorological stations across China for the period 1951-2004.Uncertainties of the gridded data and national average,linear trends and their uncertainties,as well as the homogenization effect on uncertainties are assessed.It is shown that the sampling error variances of homogenized Tmax and Tmin,which are larger in winter than in summer,have a marked northwest-southeast gradient distribution,while the sampling error variances of the original data are found to be larger and irregular.Tmax and Tmin increase in all months of the year in the study period 1951-2004,with the largest warming and uncertainties being 0.400℃ （10 yr）-1 ＋ 0.269℃ （10 yr）-1 and 0.578℃ （10 yr）-1 ＋ 0.211℃ （10 yr）-1 in February,and the least being 0.022℃ （10 yr）-1 ＋ 0.085℃ （10 yr）-1 and 0.104℃ （10 yr）-1 ＋0.070℃ （10 yr）-1 in August.Homogenization can remove large uncertainties in the original records resulting from various non-natural changes in China. 展开更多
关键词 sampling error uncertainty maximum temperature minimum temperature temperature trend
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THE MAXIMUM AND MINIMUM DEGREES OF RANDOM BIPARTITE MULTIGRAPHS 认领 引用 被引量：1
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作者 陈爱莲 张福基 李皓 《Acta Mathematica Scientia》 SCIE CSCD 2011年第3期1155-1166,共12页
In this paper the authors generalize the classic random bipartite graph model, and define a model of the random bipartite multigraphs as follows：let m = m（n） be a positive integer-valued function on n and ζ（n,m;{... In this paper the authors generalize the classic random bipartite graph model, and define a model of the random bipartite multigraphs as follows：let m = m（n） be a positive integer-valued function on n and ζ（n,m;{pk}） the probability space consisting of all the labeled bipartite multigraphs with two vertex sets A ={a_1,a_2,...,a_n} and B = {b_1,b_2,...,b_m}, in which the numbers t_（ai）,b_j of the edges between any two vertices a_i∈A and b_j∈ B are identically distributed independent random variables with distribution P{t_（ai）,b_j=k}=pk,k=0,1,2,...,where pk ≥0 and ∞Σk=0 pk=1. They obtain that X_（c,d,A）, the number of vertices in A with degree between c and d of G_（n,m）∈ζ（n, m;{pk}） has asymptotically Poisson distribution, and answer the following two questions about the space ζ（n,m;{pk}） with {pk} having geometric distribution, binomial distribution and Poisson distribution, respectively. Under which condition for {pk} can there be a function D（n） such that almost every random multigraph G_（n,m）∈ζ（n,m;{pk}） has maximum degree D（n）in A？ under which condition for {pk} has almost every multigraph G（n,m）∈ζ（n,m;{pk}） a unique vertex of maximum degree in A？ 展开更多
关键词 maximum degree minimum degree degree distribution random bipartite multigraphs
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Minimum and Maximum Resistance Status of Unicyclic Graphs 认领 引用
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作者 Meiqun CHENG Bo ZHOU 《Journal of Mathematical Research with Applications》 CSCD 2022年第5期463-475,共13页
The resistance status of a vertex of a connected graph is the sum of the resistance distance between this vertex and any other vertices of the graph. The minimum(maximum,resp.) resistance status of a connected graph i... The resistance status of a vertex of a connected graph is the sum of the resistance distance between this vertex and any other vertices of the graph. The minimum(maximum,resp.) resistance status of a connected graph is the minimum(maximum, resp.) resistance status of all vertices of the graph. In this paper, we determine the extremal values and corresponding extremal graphs for the minimum(maximum, resp.) resistance status over all unicyclic graphs of fixed order, and we also discuss the dependence of the minimum(maximum, resp.) resistance status on the girth of unicyclic graphs. 展开更多
关键词 minimum resistance status maximum resistance status resistance distance unicyclic graph extremal graph
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Minimum and Maximum Temperature Trends in Congo-Brazzaville: 1932-2010 认领 引用 被引量：2
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作者 Gaston Samba Dominique Nganga 《Atmospheric and Climate Sciences》 2014年第3期404-430,共27页
Maximum and minimum temperatures time series of Congo-Brazzaville are analyzed for trend and discontinuities over the period 1932 to 2010. Temperatures series show an irregular increase. A total of 8 synoptic stations... Maximum and minimum temperatures time series of Congo-Brazzaville are analyzed for trend and discontinuities over the period 1932 to 2010. Temperatures series show an irregular increase. A total of 8 synoptic stations show positive trends in their annual mean maximum temperature series, and 7 of them are significant, with higher trends for urban stations. Annual mean minimum temperature showed 6 stations having positive trends. This increase is in relation with observations at regional scale. However, the differences are observed between large towns (Brazzaville and Pointe-Noire), and small or rural towns (Dolisie, Sibiti, Impfondo, Djambala). Trends in diurnal temperature range (DTR) are large positive trends in maximum temperature that are mainly observed in cities. The curve of DTR shows a decreasing trend which indicates the increasing of minimum temperatures. The effects of urbanization on temperature trends are investigated. Most stations regarded as urban stations are still useful for trend analysis;being situated on the suburban of the studied cities, they are therefore, not substantially influenced by the urban heat island. 展开更多
关键词 Congo Republic Temperatures Maximum and Minimum Temperature Trends
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The Joint Distribution of the Maximum Excursion and the Minimum Excursion for Brownian Motion with Drift 认领 引用
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作者 LUe Yu-hua XU Run 《Chinese Quarterly Journal of Mathematics》 北大核心 2007年第1期57-62,共6页
In this paper, we discuss the problem of extreme value for Brownian motion with positive drift. We obtain the joint distribution of the maximum excursion and the minimum excursion.
关键词 Brownian motion ruin time the first hitting time the last exit time maximum excursion minimum excursion
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Optimal Maximum Norm Estimates and Superconvergence for GDM on Two-point Boundary Value Problems 认领 引用 被引量：4
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作者 Li Qian Jiang Ziwen 《Northeastern Mathematical Journal》 1999年第1期89-96,共8页
In this paper,we consider first order generalized difference scheme for the twopoint boundary value problem and give optimal error estimates in L∞and W1,∞ as well as some superconvergence estimates in H1 an... In this paper,we consider first order generalized difference scheme for the twopoint boundary value problem and give optimal error estimates in L∞and W1,∞ as well as some superconvergence estimates in H1 and W1,∞.The main results in this paper perfect the theory of GDM. 展开更多
关键词 Two-point Boundary Value Problem GDM Maximum Norm Superconvergence Green’s Function
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On the Distribution of the Minimum or Maximum of a Random Number of i.i.d. Lifetime Random Variables 认领 引用 被引量：1
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作者 Francisco Louzada Estela MPBereta Maria APFranco 《Applied Mathematics》 2012年第4期350-353,共4页
Statisticians are usually concerned with the proposition of new distributions. In this paper we point out that a unified and concise derivation procedure of the distribution of the minimum or maximum of a random numbe... Statisticians are usually concerned with the proposition of new distributions. In this paper we point out that a unified and concise derivation procedure of the distribution of the minimum or maximum of a random number N of indepen-dent and identically distributed continuous random variables Yi,{i = 1,2,…,N} is obtained if one compounds the probability generating function of N with the survival or the distribution func-tion of Yi. Expressions are then derived in closed form for the density, hazard and quantile func-tions of the minimum or maximum. The methodology is illustrated with examples of the distributions proposed by Adamidis and Loukas (1998), Kus (2007), Tahmasbi and Rezaei (2008), Barreto-Souza and Cribari-Neto (2009), Cancho, Louzada, and Barriga (2011) and Louzada, Roman and Cancho (2011). 展开更多
关键词 Compounding Distributions Distribution of the Maximum Distribution of the Minimum Probability Generating Function
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Distribution of the Maximum and Minimum of a Random Number of Bounded Random Variables 认领 引用
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作者 Jie Hao Anant Godbole 《Open Journal of Statistics》 2016年第2期274-285,共12页
We study a new family of random variables that each arise as the distribution of the maximum or minimum of a random number N of i.i.d. random variables X1, X2,…, XN, each distributed as a variable X with support on [... We study a new family of random variables that each arise as the distribution of the maximum or minimum of a random number N of i.i.d. random variables X1, X2,…, XN, each distributed as a variable X with support on [0, 1]. The general scheme is first outlined, and several special cases are studied in detail. Wherever appropriate, we find estimates of the parameter θ in the one-parameter family in question. 展开更多
关键词 Maximum and Minimum Random Number of i.i.d. Variables Statistical Inference
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Application of Machine-Learning-Based Objective Correction Method in the Intelligent Grid Maximum and Minimum Temperature Predictions 认领 引用
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作者 Jing Liu Chuan Ren +2 位作者 Ningle Yuan Shuai Zhang Yue Wang 《Atmospheric and Climate Sciences》 2023年第4期507-525,共19页
Post-processing correction is an effective way to improve the model forecasting result. Especially, the machine learning methods have played increasingly important roles in recent years. Taking the meteorological obse... Post-processing correction is an effective way to improve the model forecasting result. Especially, the machine learning methods have played increasingly important roles in recent years. Taking the meteorological observational data in a period of two years as the reference, the maximum and minimum temperature predictions of Shenyang station from the European Center for Medium-Range Weather Forecasts (ECMWF) and national intelligent grid forecasts are objectively corrected by using wavelet analysis, sliding training and other technologies. The evaluation results show that the sliding training time window of the maximum temperature is smaller than that of the minimum temperature, and their difference is the largest in August, with a difference of 2.6 days. The objective correction product of maximum temperature shows a good performance in spring, while that of minimum temperature performs well throughout the whole year, with an accuracy improvement of 97% to 186%. The correction effect in the central plains is better than in the regions with complex terrain. As for the national intelligent grid forecasts, the objective correction products have shown positive skills in predicting the maximum temperatures in spring (the skill-score reaches 0.59) and in predicting the minimum temperature at most times of the year (the skill-score reaches 0.68). 展开更多
关键词 Machine Learning Sliding Training Forecast Correction Maximum and Minimum Temperature
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Estimation of Return Level for Maximum Daily and Hourly Precipitation in Nagano Prefecture, Japan, Using the Extreme Value Theory 认领 引用
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作者 Fumio Maruyama 《Open Journal of Applied Sciences》 2024年第8期2065-2087,共23页
The weather in Nagano Prefecture, Japan, can be roughly classified into four types according to principal component analysis and k-means clustering. We predicted the extreme values of the maximum daily and hourly prec... The weather in Nagano Prefecture, Japan, can be roughly classified into four types according to principal component analysis and k-means clustering. We predicted the extreme values of the maximum daily and hourly precipitation in Nagano Prefecture using the extreme value theory. For the maximum daily precipitation, the vales of ξ in Matsumoto, Karuizawa, Sugadaira, and Saku were positive;therefore, it has no upper bound and tends to take large values. Therefore, it is dangerous and caution is required. The values of ξ in Nagano, Kisofukushima, and Minamishinano were determined to be zero, therefore, there was no upper limit, the probability of obtaining a large value was low, and caution was required. We predicted the maximum return levels for return periods of 10, 20, 50, and 100 years along with respective 95% confidence intervals in Nagano, Matsumoto, Karuizawa, Sugadaira, Saku, Kisofukushima, and Minamishinano. In Matsumoto, the 100-year return level was 182 mm, with a 95% CI [129, 236]. In Minamishinano, the 100-year return level was 285 mm, with a 95% CI [173, 398]. The 100-year return levels for the maximum daily rainfall were 285, 271, and 271 mm in Minamishinano, Saku, and Karuizawa, respectively, where the changes in the daily maximum rainfall were larger than those at other points. Because these values are large, caution is required during heavy rainfall. The 100-year return levels for the maximum daily and hourly precipitation were similar in Karuizawa and Saku. In Sugadaira, the 100-year return level for a maximum hourly rainfall of 107.2 mm was larger than the maximum daily rainfall. Hence, it is necessary to be careful about short-term rainfall events. 展开更多
关键词 Extreme Value Theory Maximum Daily and Hourly Precipitation Principal Component Analysis K-Means Clustering
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Treatment of Skeletal CL II Patient with Maximum Lower Incisor Protrusion and Minimum Overjet with Rahhal Functional Appliance 认领 引用
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作者 Ahmad Abdallah Rahhal 《Open Journal of Stomatology》 2018年第12期319-325,共7页
Treatment of skeletal Cl II includes functional orthopedic treatment, head-gears, extraction of the upper premolars and orthognathic surgery. To treat any patient with functional appliances (bite jumping) an adequate ... Treatment of skeletal Cl II includes functional orthopedic treatment, head-gears, extraction of the upper premolars and orthognathic surgery. To treat any patient with functional appliances (bite jumping) an adequate overjet is necessary. In this case an 11 years old female patient has skeletal CLII due to mandibular deficiency with ANB angle 8 degrees, overbite: 3 mm, overjet: 1 mm, extremely convex profile and underdeveloped chin due to the hyper muscle contraction of the lower lip to obtain oral seal. To obtain an adequate overjet lower first premolars were extracted and maximum retraction using mini screws (for maximum anchorage) was applied. Afterwards Rahhal functional appliance was used by the patient 16 hours a day for 6 months and 10 hours a day for another 6 months for retention. After that fixed orthodontic treatment was completed. Lateral cephalometrics were taken, traced and analyzed. In the result Skeletal CLI was obtained (ANB 4 degree), straight facial profile, normal over bite overjet and particular chin development were noticed. As a conclusion, in skeletal CLII malocclusions, lower incisor protrusion will cause a contraindication for functional treatment. Extraction of the lower premolars and retraction of the lower incisors followed by functional orthopedic treatment is an efficient method to treat these cases instead of waiting for orthognathic surgery, also reducing the muscle pressure on the chin will change the development characteristics of it. 展开更多
关键词 Rahhal Functional Appliance Lower Incisor Protrusion Minimum Overjet Maximum Anchorage Chin Development
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A New Method to Determine the Maximum Value of the Track Length of Alpha Particle in CR-39 Detector 认领 引用
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作者 Hussein A. Ahmed A. Mohammed A. Said Ahmad 《Materials Sciences and Applications》 2015年第2期145-151,共7页
The aim of this paper is to determine the maximum values of the track length (Lmax) of alpha particles in Nuclear Track Detector (type CR-39) using a new method by taking the relation between the etching time and the ... The aim of this paper is to determine the maximum values of the track length (Lmax) of alpha particles in Nuclear Track Detector (type CR-39) using a new method by taking the relation between the etching time and the diameter square of alpha particle with different energies at constant bulk etch rate VB (1.45 μm/hr) by using TRACK_TEST program from Brun et al. function and Yu et al. function. Using the new equation, the maximum values of the track lengths of alpha particles measured in CR-39 detector have been found to be in a good agreement with the values measured by using Brun et al. function and Yu et al. function in TRACK_TEST program. 展开更多
关键词 Maximum Value of Track Length CR-39 Range of Alpha Particle Nuclear Track Detector (NTD)
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Minimum Expenses,Maximum Savings:How to Live in China Smartly 认领 引用
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《国际人才交流》 2011年第9期58-59,共2页
For more information,please click www.echinacities.com While it's at least very annoying,and at most woefully erroneous that many Chinese people judge all foreigners to be totally minted,it's not hard to see w... For more information,please click www.echinacities.com While it's at least very annoying,and at most woefully erroneous that many Chinese people judge all foreigners to be totally minted,it's not hard to see why,when many foreigners are here living decadent lifestyles,partying on weekends(and weekdays),travelling all over the country and mincing around town with Macbooks,iPods and Ray Bans.But then there are the secret 'squirrelers',who scrimp together just enough cash to 展开更多
关键词 more Minimum Expenses,Maximum Savings
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Asymmetrical Change Characteristics of Maximum and Minimum Temperatures in Shangqiu in Recent 50 Years 认领 引用
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作者 ZHANG Yun-xia 《Meteorological and Environmental Research》 2011年第10期50-54,58,共5页
[Objective]The research aimed to analyze temporal and spatial variation characteristics of temperature in Shangqiu City during 1961-2010.[Method]Based on temperature data in eight meteorological stations of Shangqiu d... [Objective]The research aimed to analyze temporal and spatial variation characteristics of temperature in Shangqiu City during 1961-2010.[Method]Based on temperature data in eight meteorological stations of Shangqiu during 1961-2010,by using trend analysis method,the temporal and spatial evolution characteristics of annual average temperature,annual average maximum and minimum temperatures,annual extreme maximum and minimum temperatures,daily range of annual average temperature in Shangqiu City were analyzed.M-K method was used to determine mutation year of temperature.[Result]The annual average temperature,annual average minimum temperature and annual extreme minimum temperature respectively rose at 0.122,0.255 and 0.488℃/10 a.The variation trend of annual average maximum temperature wasn’t obvious.The daily range of annual average temperature and annual extreme maximum temperature respectively declined at-0.217 and-0.292℃/10 a.Seen from spatial distribution,the increase amplitudes of annual average temperature,annual average minimum temperature and annual extreme minimum temperature were all large in the east and small in the west.The decrease amplitude of daily range of annual average temperature was large in the east and small in the west.The decrease amplitude of annual extreme maximum temperature was large in the west and small in the east.The annual average maximum temperature had trends of increase and decrease.The annual average temperature,annual average minimum temperature and daily range of annual average temperature all mutated in 1997.The annual average maximum temperature didn’t have obvious mutation point.The annual extreme maximum temperature mutated in 1973.The annual extreme minimum temperature respectively mutated in 1989 and 1999.[Conclusion]The research played important guidance significances in adjustment of agricultural production structure,regional climate planning,reasonably using climate resource and replying climate change in Shangqiu City. 展开更多
关键词 Average temperature Maximum and minimum temperatures Extreme temperature Daily range Climate change Temporal and spatial variation characteristics China
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融合地形特征和神经网络的日最高/最低气温预报订正方法研究 认领 引用 被引量：1
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作者 卢姝 许霖 +3 位作者 顾雪 周悦 戴泽军 陶雅琴 《高原气象》 CSCD 北大核心 2026年第2期500-514,共15页
日最高、最低气温的预报是天气预报业务的重要组成部分,其精度提升对保障社会经济活动具有重要意义。针对数值模式在复杂地形区域系统性偏差显著的问题,本研究以湖南省为试验区(具有“凹”字形三级阶梯地貌,涵盖山地、丘陵、平原等多种... 日最高、最低气温的预报是天气预报业务的重要组成部分,其精度提升对保障社会经济活动具有重要意义。针对数值模式在复杂地形区域系统性偏差显著的问题,本研究以湖南省为试验区(具有“凹”字形三级阶梯地貌,涵盖山地、丘陵、平原等多种下垫面类型),提出一种融合地理特征聚类的深度学习改进方案。基于欧洲中期天气预报中心(European Centre for Medium Range Weather Forecasts,ECMWF)模式预报场、中国气象局陆面数据同化系统(CMA Land Data Assimilation System,CLDAS)再分析数据和地理变量,首先构建基准卷积神经网络CNN模型并针对地形特征处理策略设置三类对照实验:方案1(K-means聚类地理变量)、方案2(标准化非聚类地理变量)及方案3(无地理变量)。对比实验表明,方案1对24 h最高/低温度平均绝对误差MAE较方案3分别降低4.7%/9.4%,较方案2预报技巧提升2.5%/1.4%,证实地理特征聚类处理对模型性能具有显著增益。因此,优选方案1发展了未来72 h气温预报CNN-TC(Terrain Correction)模型。该模型表现出显著预报优势:相较ECMWF产品,最高/低温MAE降幅达23.5%~37.3%/20.8%~26.9%;较中央气象台指导预报产品SCMOC,最高/低温度误差降低18.7%~27.6%/26.8%~32.3%,其中24 h预报时效下,最高/低温度空间分布MAE区间由1.2~5.8℃/0.8~5.9℃(ECMWF)降低至0.9~1.7℃/0.8~1.7℃,区域稳定性大幅提升。分月检验表明,CNN-TC模型在所有月份均保持最优性能,MAE相对降幅覆盖5.6%~59.1%(最高温度)和6.3%~47.8%(最低温度)。典型强天气过程检验中,模型成功捕捉2022年11月寒潮过程的降温特征,较ECWMF和SCMOC表现均为最优,显示出优异的极端天气应对能力。本研究证实通过深度学习耦合地形特征聚类,可有效解决数值模式在复杂下垫面区域的系统性偏差问题,为山地气候区精细化气象服务提供了可靠的技术方案。 展开更多
关键词 日最高/最低气温 地理变量 卷积神经网络 K-means方法
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典型区域供冷系统用户换热站工艺水力学分析 认领 引用 被引量：2
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作者 旷金国 王朝晖 +3 位作者 许健 胡勣 王昭强 罗曙光 《暖通空调》 2026年第1期93-103,共11页
对典型区域供冷系统用户换热站工艺配置进行了分类,对每种工艺的设计与运行工况进行了水力学分析。结果表明:在小流量负荷率时,工艺3~6具有更小的最小资用压差,比工艺1、2有较大的节能优势;工艺6采用调节阀先后调节策略运行后,可以承受... 对典型区域供冷系统用户换热站工艺配置进行了分类,对每种工艺的设计与运行工况进行了水力学分析。结果表明:在小流量负荷率时,工艺3~6具有更小的最小资用压差,比工艺1、2有较大的节能优势;工艺6采用调节阀先后调节策略运行后,可以承受较大的管网压差及变化,调节精度高,有较大适用范围;在水泵扬程允许的条件下,工艺1可以取消静态平衡阀;工艺3、4比工艺1、2有较大的实际可调比,工艺4的阀门先后调节策略具有较好的调节精度;由于采用高可调比调节阀,工艺5、6可以克服管网压差变化对实际可调比变化的影响。本文提出的理论分析方法为换热站工艺选择与优化设计提供了理论依据,也可作为管网运行优化的理论基础。 展开更多
关键词 区域供冷 用户换热站 工艺 水力学 最小资用压差 最大管网压差 调节精度
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TENSOR COMPLETION VIA MINIMUM AND MAXIMUM OPTIMIZATION WITH NOISE 认领 引用
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作者 Chuanlong Wang Rongrong Xue 《Journal of Computational Mathematics》 SCIE CSCD 2026年第3期650-669,共20页
In this paper,the novel optimization model for solving tensor completion with noise is proposed,its objective function is a convex combination of the minimum nuclear norm and maximum nuclear norm.The necessary conditi... In this paper,the novel optimization model for solving tensor completion with noise is proposed,its objective function is a convex combination of the minimum nuclear norm and maximum nuclear norm.The necessary condition and sufficient condition of the stationary point and optimal solution are discussed.Based on the proximal gradient algorithm and feasible direction method,we design the new algorithm for solving the proposed nonconvex and nonsmooth optimization problem and prove that the sub-sequence generated by the new algorithm converges to the stationary point.Finally,experimental results on the random sample completions and images show that the proposed optimization and algorithm are superior to the compared algorithms in CPU time or precision. 展开更多
关键词 Tensor completion with noise Minimum and maximum optimization Proximal gradient algorithm Feasible direction method
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孔轴类零件作用边界的一般化判别方法 认领 引用
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作者 唐哲敏 焦云堃 +1 位作者 秦玲 黄美发 《机械设计与研究》 CSCD 北大核心 2026年第2期21-26,共6页
孔轴类零件是机械领域中典型的一类零部件。在评定其最小实体要求和最大实体要求时,缺乏一种通用的判别方法,明确判定算法是否成功找到测点集的作用边界。为解决这一问题,提出了一种基于边界点矩阵的通用判别方法。通过对孔轴测点集与... 孔轴类零件是机械领域中典型的一类零部件。在评定其最小实体要求和最大实体要求时,缺乏一种通用的判别方法,明确判定算法是否成功找到测点集的作用边界。为解决这一问题,提出了一种基于边界点矩阵的通用判别方法。通过对孔轴测点集与作用边界之间的相对位置、相对距离等关键关系进行分析,建立了孔轴类零件的作用边界模型并分析了典型坐标系下的模型变换。进一步探讨了作用边界判别的基本数理逻辑形式及其便于求解的推论,并借助边界点矩阵的性质,将作用边界判别的逻辑问题转化为等效的通用判别方法。最终,通过一个具体实例验证了所提出的孔轴类零件作用边界通用判别方法的有效性。 展开更多
关键词 判别方法 作用边界 最大实体要求 最小实体要求 几何误差评定
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基于线路参数灵敏度的EMTR配网故障定位性能影响分析 认领 引用
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作者 王科 胡逸 +1 位作者 徐肖伟 杨庆 《高压电器》 CAS CSCD 北大核心 2026年第6期105-112,共8页
文中提出了一种基于故障电流能量镜像最小值的电磁时间反演故障定位方法,但目前该方法要求反向阶段建立的仿真模型与正向阶段故障时的实际线路模型参数保持一致,从而限制了其在实际中的应用。因此基于该方法在正向阶段和反向阶段模型参... 文中提出了一种基于故障电流能量镜像最小值的电磁时间反演故障定位方法,但目前该方法要求反向阶段建立的仿真模型与正向阶段故障时的实际线路模型参数保持一致,从而限制了其在实际中的应用。因此基于该方法在正向阶段和反向阶段模型参数的差异,文中利用PSCAD仿真软件搭建了10 kV配电网线路模型并对其进行频域理论推导,通过仿真分析了不同线路参数灵敏度下该方法的定位性能,并搭建了同轴电缆试验模型进行验证。结果表明:①相比于正向阶段的线路电感参数,当反向阶段的线路电感参数设置在0.95~1.1倍范围内,该方法都能够实现高阻接地故障定位;②该方法可实现实际发生未知接地故障电阻的精确定位,且为提高其整体的定位性能,建议在反向阶段线路横向分支中设置高阻假想接地故障;③通过搭建的同轴电缆试验模型分析了故障阻抗未知情况下对方法故障定位性能的影响,综合故障定位误差最大为5 m。 展开更多
关键词 故障电流能量镜像最小值 电磁时间反演 线路参数灵敏度 故障定位 定位性能
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