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Rank Functions of Fuzzy Greedoids 被引量:1
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作者 Steven J. Tedford 《Open Journal of Discrete Mathematics》 2015年第4期65-73,共9页
Fuzzy greedoids were recently introduced as a fuzzy set generalization of (crisp) greedoids. We characterize fuzzy languages which define fuzzy greedoids, give necessary properties and sufficient properties of the fuz... Fuzzy greedoids were recently introduced as a fuzzy set generalization of (crisp) greedoids. We characterize fuzzy languages which define fuzzy greedoids, give necessary properties and sufficient properties of the fuzzy rank function of a fuzzy greedoid, give a characterization of the rank function for a weighted greedoid, and discuss the rank closure of a fuzzy greedoid. 展开更多
关键词 FUZZY SYSTEM MODELS Greedoids FUZZY rank function
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A Note on Submodularity Preserved Involving the Rank Functions
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作者 Min Li Dong-Lei Du +1 位作者 Da-Chuan Xu Zhen-Ning Zhang 《Journal of the Operations Research Society of China》 EI CSCD 2019年第3期399-407,共9页
In many kinds of games with economic significance,it is very important to study the submodularity of functions.In this paper,wemainly study the problem of maximizing a concave function over an intersection of two matr... In many kinds of games with economic significance,it is very important to study the submodularity of functions.In this paper,wemainly study the problem of maximizing a concave function over an intersection of two matroids.We obtain that the submod-ularity may not be preserved,but it involves one maximal submodular problem(or minimal supermodular problem)with some conditions.Moreover,we also present examples showing that these conditions can be satisfied. 展开更多
关键词 MATROID Submodular function rank function Convexclosure GAME
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Rank functions and state spaces of K_0
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作者 冯良贵 郝志峰 《Science China Mathematics》 SCIE 2001年第3期351-356,共6页
While the formulations of localization rank and stably free rank are given, the characterizations of elements are obtained for a class of VN regular ring. For a ring R, the characters of some properties of K0R are als... While the formulations of localization rank and stably free rank are given, the characterizations of elements are obtained for a class of VN regular ring. For a ring R, the characters of some properties of K0R are also given in terms of the state space of K0. 展开更多
关键词 rank function state space K0 group
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Robust ranking of multi-criteria alternatives using value functions compatible with holistic preference information
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作者 SLOWINSKI Roman GRECO Salvatore2 +1 位作者 FIGUEIRA José Rui MOUSSEAU Vincent 《重庆邮电大学学报(自然科学版)》 2008年第3期324-334,共11页
We present two recent methods,called UTAGMS and GRIP,from the viewpoint of robust ranking of multi-criteria alternatives.In these methods,the preference information provided by a single or multiple Decision Makers(DMs... We present two recent methods,called UTAGMS and GRIP,from the viewpoint of robust ranking of multi-criteria alternatives.In these methods,the preference information provided by a single or multiple Decision Makers(DMs)is composed of holistic judgements of some selected alternatives,called reference alternatives.The judgements express pairwise comparisons of some reference alternatives(in UTAGMS),and comparisons of selected pairs of reference alternatives from the viewpoint of intensity of preference(in GRIP).Ordinal regression is used to find additive value functions compatible with this preference information.The whole set of compatible value functions is then used in Linear Programming(LP)to calculate a necessary and possible weak preference relations in the set of all alternatives,and in the set of all pairs of alternatives.While the necessary relation is true for all compatible value functions,the possible relation is true for at least one compatible value function.The necessary relation is a partial preorder and the possible relation is a complete and negatively transitive relation.The necessary relations show consequences of the given preference information which are robust because "always true".We illustrate this methodology with an example. 展开更多
关键词 信息处理 选择方案 函数 计算机技术
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新的PageRank优化算法 被引量:4
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作者 蒋永辉 吴洪丽 《计算机工程与应用》 CSCD 2012年第6期94-95,154,共3页
为了克服PageRank在搜索过程中重复性地把当前受欢迎的网页放在搜索结果的首要位置,而不受欢迎的网页被大多数用户忽略的问题,采用了一种改进的评估函数及有效的用户模型,获得了一个新的PageRank优化算法。实验结果表明,该算法达到了较... 为了克服PageRank在搜索过程中重复性地把当前受欢迎的网页放在搜索结果的首要位置,而不受欢迎的网页被大多数用户忽略的问题,采用了一种改进的评估函数及有效的用户模型,获得了一个新的PageRank优化算法。实验结果表明,该算法达到了较好的公平性。 展开更多
关键词 PAGErank算法 评估函数 用户模型
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线性程序的Ranking函数自动合成 被引量:1
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作者 李骏 李轶 +1 位作者 冯勇 秦小林 《四川大学学报(工程科学版)》 EI CAS CSCD 北大核心 2009年第5期176-181,共6页
针对判定一个程序终止性的经典方法Ranking函数法,运用半代数系统的概念,把程序终止性问题转换为求半代数系统的Ranking函数。然后运用符号计算工具DISCOV-ERER和Farkas引理,求出函数参数存在的充分必要条件,并根据符号计算理论的方法... 针对判定一个程序终止性的经典方法Ranking函数法,运用半代数系统的概念,把程序终止性问题转换为求半代数系统的Ranking函数。然后运用符号计算工具DISCOV-ERER和Farkas引理,求出函数参数存在的充分必要条件,并根据符号计算理论的方法自动合成Ranking函数。通过计算代数理论的证明和试验的验证,并与其他方法做了比较,这种方法是高效合理的。 展开更多
关键词 DISCOVERER Farkas’lemma ranking函数 半代数系统 程序终止性 程序验证
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A Systemic-Functional Approach to English Ambiguity
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作者 张静 《海外英语》 2014年第6X期254-255,共2页
This thesis chooses the theory of rank scale and the theory of meta-function in the framework of Systemic-Functional Grammar(SFG)to study ambiguity.It firstly analyzes ambiguities occurring at the rank of morpheme,wor... This thesis chooses the theory of rank scale and the theory of meta-function in the framework of Systemic-Functional Grammar(SFG)to study ambiguity.It firstly analyzes ambiguities occurring at the rank of morpheme,word or phrase.Then it studies ambiguities at the rank of clause,from ideational ambiguity to textual ambiguity.This study shows that SFG can give a systematic and comprehensive interpretation of English ambiguity. 展开更多
关键词 English AMBIGUITY SFG rank scale meta-function
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Log-Rank Test for Comparing Survival Curves of Neonatal Mortality Characteristic Groups in River Nile State-Sudan
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作者 Abdellateef Khalifa Hamid Ali Amin Ibrahim Adam Mohammed 《Open Journal of Statistics》 2022年第4期532-547,共16页
This paper concerns the Log-rank test for comparing survival curves of neonatal mortality characteristic groups in River Nile State, Sudan. In this paper, log-rank test is used to compare two or more survival curves f... This paper concerns the Log-rank test for comparing survival curves of neonatal mortality characteristic groups in River Nile State, Sudan. In this paper, log-rank test is used to compare two or more survival curves for the characteristics of newborn associated with newborn death after using Kaplan-Meier methods to estimate and graph survival curves for the variable of interest as (sex of newborn, weight of newborn, gestational age, mode of delivery and resident type), at the hospital of River Nile state—Sudan, with a sample size 700 of newborn in which the admission to the Neonatal Intensive Care Unit (NICU) of those hospitals during the period 2018-2020. In term of risk of death for newborn we found that 25% of sample study for newborns who were born in River Nile State-Sudan died. In addition, we conclude that after the log-rank statistics and Kaplan-Meier methods were applied, gender does not affect the newborn’s risk of survival, while the risk of survival increases when the birth weight is greater than 4.35 kg and the gestational age is greater than 42 weeks. There is no difference in the probability of survival for newborns whether the delivery is normal or cesarean. However, newborns are significantly more likely to survive in urban areas than in rural areas. 展开更多
关键词 Neonatal Mortality Log-rank Test Survival function Kaplan-Meier Method
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Finite Dimensional Approximation of the Monodromy Operator of a Periodic Delay Differential Equation with Piecewise Constant Orthonormal Functions
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作者 Eli A. Vazquez Joaquin Collado 《Applied Mathematics》 2018年第11期1315-1337,共23页
Using piecewise constant orthonormal functions, an approximation of the monodromy operator of a Linear Periodic Delay Differential Equation (PDDE) is obtained by approximating the integral equation corresponding to th... Using piecewise constant orthonormal functions, an approximation of the monodromy operator of a Linear Periodic Delay Differential Equation (PDDE) is obtained by approximating the integral equation corresponding to the PDDE as a linear operator over the space of initial conditions. This approximation allows us to consider the state space as finite dimensional resulting in a finite matrix approximation whose spectrum converges to the spectrum of the monodromy operator. 展开更多
关键词 MONODROMY Operator PERIODIC Delay Differential Equations WALSH functionS Block Pulse functionS Finite rank Approximation
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Latent spatio-temporal activity structures: a new approach to inferring intra-urban functional regions via social media check-in data 被引量:7
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作者 Ye Zhi Haifeng Li +5 位作者 Dashan Wang Min Deng Shaowen Wang Jing Gao Zhengyu Duan Yu Liu 《Geo-Spatial Information Science》 CSCD 2016年第2期中插1-中插1,94-105,共13页
This article introduces a novel low rank approximation (LRA)-based model to detect the functional regions with the data from about 15 million social media check-in records during a year-long period in Shanghai, China.... This article introduces a novel low rank approximation (LRA)-based model to detect the functional regions with the data from about 15 million social media check-in records during a year-long period in Shanghai, China. We identified a series of latent structures, named latent spatio-temporal activity structures. While interpreting these structures, we can obtain a series of underlying associations between the spatial and temporal activity patterns. Moreover, we can not only reproduce the observed data with a lower dimensional representative, but also project spatio-temporal activity patterns in the same coordinate system. With the K-means clustering algorithm, five significant types of clusters that are directly annotated with a combination of temporal activities can be obtained, providing a clear picture of the correlation between the groups of regions and different activities at different times during a day. Besides the commercial and transportation dominant areas, we also detected two kinds of residential areas, the developed residential areas and the developing residential areas.We further interpret the spatial distribution of these clusters using urban form analytics. The results are highly consistent with the government planning in the same periods, indicating that our model is applicable to infer the functional regions from social media check-in data and can benefit a wide range of fields, such as urban planning, public services, and location-based recommender systems. 展开更多
关键词 Human activity pattern functional region low rank approximation (LRA) social media CHECK-IN DATA Shanghai
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语义功能视角下专家和新手的英语学术论文关键词对比研究
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作者 刘永厚 汪杉 《西安外国语大学学报》 北大核心 2025年第3期1-7,共7页
学术论文的关键词指能够概括主要研究内容的功能性词汇,具有引导阅读和文献索引的双重作用。本研究选取应用语言学领域学术专家和新手的英语学术论文各150篇,自建语料库,旨在对比和分析两组作者在学术论文关键词的语义功能分布和排序特... 学术论文的关键词指能够概括主要研究内容的功能性词汇,具有引导阅读和文献索引的双重作用。本研究选取应用语言学领域学术专家和新手的英语学术论文各150篇,自建语料库,旨在对比和分析两组作者在学术论文关键词的语义功能分布和排序特征方面的差异。研究发现,学术新手在关键词选用上存在关键词排序逻辑混乱、过度使用泛化词、关键词语义功能类型不够丰富等问题,以及学术新手在选择关键词时常照搬论文标题成分,缺乏归纳意识。本文创新性地提出了“关键词语义功能排序指数”,基此量化分析关键词的排序特点和潜在逻辑,为提升学习者的关键词标引能力提供了科学依据。 展开更多
关键词 学术写作 关键词标引 关键词排序 语义功能
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Effects of professional rehabilitation training on the recovery of neurological function in young stroke patients 被引量:11
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作者 Chao-jin-zi Li Xiao-xia Du +7 位作者 Kun Yang Lu-ping Song Peng-kun Li Qiang Wang Rong Sun Xiao-ling Lin Hong-yu Lu Tong Zhang 《Neural Regeneration Research》 SCIE CAS CSCD 2016年第11期1766-1772,共7页
Young stroke patients have a strong desire to return to the society, but few studies have been conducted on their rehabilitation training items, intensity, and prognosis. We analyzed clinical data of young and middle-... Young stroke patients have a strong desire to return to the society, but few studies have been conducted on their rehabilitation training items, intensity, and prognosis. We analyzed clinical data of young and middle-aged/older stroke patients hospitalized in the Department of Neurological Rehabilitation, China Rehabilitation Research Center, Capital Medical University, China from February 2014 to May 2015. Results demonstrated that hemorrhagic stroke (59.6%) was the primary stroke type found in the young group, while ischemic stroke (60.0%) was the main type detected in the middle-aged/older group. Compared with older stroke patients, education level and incidence of hyperhomocysteinemia were higher in younger stroke patients, whereas, incidences of hypertension, diabetes, and heart disease were lower. The average length of hospital stay was longer in the young group than in the middle-aged/older group. The main risk factors observed in the young stroke patients were hypertension, drinking, smoking, hyperlipidemia, hyperhomocysteinemia, diabetes, previous history of stroke, and heart disease. The most accepted rehabilitation program consisted of physiotherapy, occupational therapy, speech therapy, acupuncture and moxibustion. Average rehabilitation training time was 2.5 hours/day. Barthel Index and modified Rankin Scale scores were increased at discharge. Six months after discharge, the degree of occupational and economic satisfaction declined, and there were no changes in family life satisfaction. The degrees of other life satisfaction (such as friendship) improved. The degree of disability and functional status improved significantly in young stroke patients after professional rehabilitation, but the number of patients who returned to society within 6 months after stroke was still small. 展开更多
关键词 nerve regeneration young stroke patients risk factors recovery of neurological function prognosis Life Satisfaction Questionnaire Barthel Index modified rank Scale neural regeneration
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不同煤阶煤大分子模型构建及对比 被引量:4
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作者 张晨 张松航 +3 位作者 唐书恒 张守仁 李哲 范志辉 《现代地质》 北大核心 2025年第3期839-855,共17页
煤大分子模型是研究煤的物理化学性质和高效利用的基础,然而,当前尚缺乏反映不同煤阶煤性质的大分子模型的构建和对比。为此,本研究利用工业分析和元素分析,以及核磁共振碳谱、红外光谱、X射线光电子能谱等测试手段,结合前人数据,构建... 煤大分子模型是研究煤的物理化学性质和高效利用的基础,然而,当前尚缺乏反映不同煤阶煤性质的大分子模型的构建和对比。为此,本研究利用工业分析和元素分析,以及核磁共振碳谱、红外光谱、X射线光电子能谱等测试手段,结合前人数据,构建并搜集了河曲煤、孝义煤、店坪煤、高阳煤、阳泉煤、赵庄煤等横跨褐煤到无烟煤(R_(O)=0.46%~3.21%)的13个不同煤阶煤大分子模型序列。煤大分子结构参数显示,随煤阶升高,芳香结构中芳碳率呈3阶段增加演化趋势;桥周比、桥接芳碳均线性增加,侧支芳碳、氧接芳碳在煤变质第一次跃变点以前快速减少。脂肪结构中脂碳率与芳碳率相反,呈3阶段减小趋势;甲基碳第一次跃变点之前增加最后减小;亚甲基碳呈波动变化与三次煤化跃变对应;氧接脂碳的变化情况规律不明显。含氧官能团含量则随煤阶的升高而减少。范德华能和键伸缩能的降低对分子稳定性起主导作用,氢键能只在低阶煤(褐煤)和中阶煤(长焰煤、气煤)及分子之间起作用。低阶煤(褐煤)和中阶煤(长焰煤到瘦煤)的多分子总能量低于等量单分子的能量,而高阶煤(贫煤和无烟煤)由于π-π作用多分子能量高于等量单分子能量。总体上,文中所建大分子模型序列反映了煤变质规律,揭示了煤分子能量构成。研究成果有望能为进一步的煤大分子模拟工作提供基础煤分子构型。 展开更多
关键词 分子模型 官能团 能量构型 煤阶
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伪辛空间上格的秩生成函数和特征多项式及Poincaré多项式
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作者 莫晓云 陈修焕 赵燕冰 《高校应用数学学报(A辑)》 北大核心 2025年第3期345-354,共10页
利用有限域上伪辛空间中子空间的计数定理,研究了有限伪辛群作用下子空间轨道生成格的秩生成函数、特征多项式和Poincaré多项式,并且确定了它们的表示式.
关键词 伪辛空间 秩生成函数 特征多项式 Poincaré多项式
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水光互补系统接入电网的适应性分析方法研究 被引量:5
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作者 段钇江 曲艺 《水电能源科学》 北大核心 2025年第3期219-222,195,共5页
为量化分析新能源的大规模接入对电力系统的多方面影响,从电源端多场站光伏消纳问题着手,考虑水光互补系统安全并网,提出一套面向水光互补系统接入电网的适应性分析方法。该分析方法从安全性能力、并网特性和接纳能力3个方面,并结合“... 为量化分析新能源的大规模接入对电力系统的多方面影响,从电源端多场站光伏消纳问题着手,考虑水光互补系统安全并网,提出一套面向水光互补系统接入电网的适应性分析方法。该分析方法从安全性能力、并网特性和接纳能力3个方面,并结合“序关系分析法+模糊评价法”进行综合量化评估。最后,以某水光互补系统为例进行适应性评估。研究结果表明,水光互补后该水电站具备打捆700 MW光伏的能力,适应性综合评分为0.9105,可确保近区电网安全稳定运行。 展开更多
关键词 水光互补 适应性分析 隶属度函数 序关系分析法 综合评价方法
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融合多策略的沙猫群算法及其应用 被引量:1
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作者 班云飞 张达敏 +1 位作者 左锋琴 沈倩雯 《计算机工程与设计》 北大核心 2025年第7期2054-2062,共9页
针对沙猫群算法易陷入局部最优、收敛速度慢等问题,提出一种融合多策略的沙猫群算法。将经典SCSO搜索阶段的位置更新公式做结构变体,增加种群的多样性;提出自适应麻雀因子提高算法的收敛速度和精度;在开发阶段引入动态螺旋探索策略,以... 针对沙猫群算法易陷入局部最优、收敛速度慢等问题,提出一种融合多策略的沙猫群算法。将经典SCSO搜索阶段的位置更新公式做结构变体,增加种群的多样性;提出自适应麻雀因子提高算法的收敛速度和精度;在开发阶段引入动态螺旋探索策略,以一种选择概率控制该策略的作用阶段,避免算法陷入局部最优。与其它算法在8个基准测试函数和Wilcoxon秩和检验上进行对比,实验结果表明,改进算法的寻优精度高、收敛速度快且具有跳出局部最优的能力,同时将其应用在5G基站中心选址问题中,验证了算法在实际应用中的有效性和可行性。 展开更多
关键词 沙猫群算法 结构变体 自适应麻雀因子 动态螺旋探索策略 5G基站中心选址 基准测试函数 秩和检验
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“前X”格式“就高类化”功能的形成机制
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作者 邵洪亮 朱昊华 《汉语学习》 北大核心 2025年第6期24-32,共9页
说话人对主观上认同的个体进行归类时,“前X”格式有“就高类化”功能。“就高”是指为个体归类时,该个体通常处于X的后半部分且往往是末端部分;“类化”是指将X以内的所有个体视为一类,强调对外的异质性、差异性而忽略其内部的差异性... 说话人对主观上认同的个体进行归类时,“前X”格式有“就高类化”功能。“就高”是指为个体归类时,该个体通常处于X的后半部分且往往是末端部分;“类化”是指将X以内的所有个体视为一类,强调对外的异质性、差异性而忽略其内部的差异性。无论用于表达已然事件、未然事件还是消极事件,“前X”均有此功能。此外,X的取值在整数与分数中有不同倾向,其规律为取整数时多为偶数、五的倍数;取分数时分子倾向于整数。“就高类化”功能的形成与空间方位词隐喻,以及语言表达过程中的身份认同、面子维护有一定关联。 展开更多
关键词 “前X”格式 “就高类化”功能 方位词隐喻 身份认同
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几何意义下直线段υ=μ上q-级正交模糊数的分布与排序
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作者 王明新 王贵君 《模糊系统与数学》 北大核心 2025年第1期39-46,共8页
作为毕达哥拉斯模糊数(PFN)的进一步扩展,q-级正交模糊数(q-ROFN)已成为处理更大范围内多属性信息群体决策问题的重要工具.本文首先通过反例指出现行得分函数和排序准则对υ=μ上q-级正交模糊数的排序问题存在一些缺陷,并通过几何方法... 作为毕达哥拉斯模糊数(PFN)的进一步扩展,q-级正交模糊数(q-ROFN)已成为处理更大范围内多属性信息群体决策问题的重要工具.本文首先通过反例指出现行得分函数和排序准则对υ=μ上q-级正交模糊数的排序问题存在一些缺陷,并通过几何方法分析这些排序结果的不妥之处;其次,在几何背景下以最小q-级正交模糊数(0,1)为参照物给出距离因子概念,并结合犹豫度提出q-级正交模糊数新的得分函数及其排序准则,进而讨论得分函数的单调性;最后,利用多元函数条件极值法(拉格朗日乘数法)研究直线段υ=μ上的得分函数的最值问题,并通过存在最值点说明所新得分函数确实具有合理性.此外,通过实例分析阐述了新方法不仅克服了已有方法的缺陷,而且更具有合理性和优越性. 展开更多
关键词 q-级正交模糊数 距离因子 得分函数 排序准则 极值点
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混合改进的蜜獾优化算法
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作者 谢高源 张亚明 +2 位作者 普蝶 普东琪 钱政弘 《现代电子技术》 北大核心 2025年第7期163-168,共6页
针对蜜獾优化算法收敛速度不够快、容易陷入局部最优解和全局搜索能力不够强的问题,提出一种混合改进的蜜獾优化算法(HIHBA)。融入螺旋搜索策略,通过螺旋搜索逐步增加搜索半径和搜索角度,使得算法能够更广泛地搜索整个解空间,从而跳出... 针对蜜獾优化算法收敛速度不够快、容易陷入局部最优解和全局搜索能力不够强的问题,提出一种混合改进的蜜獾优化算法(HIHBA)。融入螺旋搜索策略,通过螺旋搜索逐步增加搜索半径和搜索角度,使得算法能够更广泛地搜索整个解空间,从而跳出局部最优解,更快地找到全局最优解;引入柯西变异策略进一步增强算法的全局搜索能力。对改进后的HIHBA算法与其他算法在8个基准函数上进行相同条件的对比测试,并通过Wilcoxon秩和检验进一步验证其性能。仿真结果表明,HIHBA在收敛速度和收敛精度上取得了显著的提升,与其他算法相比具有更强的竞争力和更优越的综合性能。 展开更多
关键词 蜜獾优化算法 螺旋搜索策略 柯西变异 全局最优解 测试函数 秩和检验
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基于低秩Gramian的二阶双线性系统保结构模型降阶
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作者 张岩松 肖志华 祁振中 《数学进展》 北大核心 2025年第5期1137-1150,共14页
针对二阶双线性系统,首先将其转化为等价的一阶双线性系统形式,然后利用L aguerre函数构造该等价双线性系统的可控和可观Gramian的近似低秩分解因子.在此过程中,通过递归公式来求解低秩因子,这使其更加灵活和高效.其次,根据二阶双线性系... 针对二阶双线性系统,首先将其转化为等价的一阶双线性系统形式,然后利用L aguerre函数构造该等价双线性系统的可控和可观Gramian的近似低秩分解因子.在此过程中,通过递归公式来求解低秩因子,这使其更加灵活和高效.其次,根据二阶双线性系统Gramian的结构对低秩因子进行分块,构造二阶双线性系统相应的低秩近似Gramian,进而由低秩平方根方法得到二阶双线性系统的保结构降阶模型.此外,结合主子空间投影方法改进了上述算法,提高了算法的数值鲁棒性.最后,通过数值算例验证了所提方法的有效性. 展开更多
关键词 模型降阶 二阶双线性系统 LAGUERRE函数 低秩Gramian 主子空间
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