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Improved Term Weighting Technique for Automatic Web Page Classification
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作者 Kathirvalavakumar Thangairulappan Aruna Devi Kanagavel 《Journal of Intelligent Learning Systems and Applications》 2016年第4期63-76,共14页
Automatic web page classification has become inevitable for web directories due to the multitude of web pages in the World Wide Web. In this paper an improved Term Weighting technique is proposed for automatic and eff... Automatic web page classification has become inevitable for web directories due to the multitude of web pages in the World Wide Web. In this paper an improved Term Weighting technique is proposed for automatic and effective classification of web pages. The web documents are represented as set of features. The proposed method selects and extracts the most prominent features reducing the high dimensionality problem of classifier. The proper selection of features among the large set improves the performance of the classifier. The proposed algorithm is implemented and tested on a benchmarked dataset. The results show the better performance than most of the existing term weighting techniques. 展开更多
关键词 Web Page Classification term-weighting Scheme Feature Selection Feature Extraction Artificial Neural Network Back Propagation
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Supervised Contrastive Learning with Term Weighting for Improving Chinese Text Classification
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作者 Jiabao Guo Bo Zhao +2 位作者 Hui Liu Yifan Liu Qian Zhong 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2023年第1期59-68,共10页
With the rapid growth of information retrieval technology,Chinese text classification,which is the basis of information content security,has become a widely discussed topic.In view of the huge difference compared with... With the rapid growth of information retrieval technology,Chinese text classification,which is the basis of information content security,has become a widely discussed topic.In view of the huge difference compared with English,Chinese text task is more complex in semantic information representations.However,most existing Chinese text classification approaches typically regard feature representation and feature selection as the key points,but fail to take into account the learning strategy that adapts to the task.Besides,these approaches compress the Chinese word into a representation vector,without considering the distribution of the term among the categories of interest.In order to improve the effect of Chinese text classification,a unified method,called Supervised Contrastive Learning with Term Weighting(SCL-TW),is proposed in this paper.Supervised contrastive learning makes full use of a large amount of unlabeled data to improve model stability.In SCL-TW,we calculate the score of term weighting to optimize the process of data augmentation of Chinese text.Subsequently,the transformed features are fed into a temporal convolution network to conduct feature representation.Experimental verifications are conducted on two Chinese benchmark datasets.The results demonstrate that SCL-TW outperforms other advanced Chinese text classification approaches by an amazing margin. 展开更多
关键词 Chinese text classification Supervised Contrastive Learning(SCL) term weighting(TW) Temporal Convolution Network(TCN)
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Fetal Thigh Circumference versus Fetal Abdominal Subcutaneous Tissue Thickness in Prediction of Fetal Weight in Term Pregnant Women
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作者 Mohamed El-Mandooh Aya Hassan Sarah Safwat 《Open Journal of Obstetrics and Gynecology》 2023年第9期1580-1594,共15页
Background: Fetal weight estimation by ultrasound is an important factor in obstetrics;it is directly related to the gestational age which helps to plan the mode of delivery and labor management. Objective: to compare... Background: Fetal weight estimation by ultrasound is an important factor in obstetrics;it is directly related to the gestational age which helps to plan the mode of delivery and labor management. Objective: to compare between fetal thigh circumference (TC) and abdominal subcutaneous tissue thickness (SCT) in estimating birthweight in term pregnant women. Patients and Methods: This prospective cohort study was conducted at outpatient clinic or emergency room, Obstetrics and Gynecology Department, Faculty of Medicine, Ain Shams University Maternity Hospitals from March 2022 until May 2023. During this study, 100 term pregnant females with gestational age 37 - 40 weeks attended El Demerdash Maternity Hospital and scheduled for delivery either at outpatient clinic or emergency room were enrolled, after consenting each of them. Basic fetal biometry was performed by an expert and professional medical personnel to ensure the accuracy of examination results. Fetal abdominal subcutaneous thickness and fetal thigh circumference were measured for assessment of gestational age and correlated with actual fetal body weight. In the current study, three formulas;Hadlock, Vintzileos’ and SCT formula were correlated with actual fetal body weight after birth. Results: The present study revealed that TC formula is closer to the actual birth weight, followed by Hadlock formula, while the SCT formula is the furthest from it. Conclusion: To increase the accuracy of birth estimations, regular ultrasound examinations should include fetal thigh circumference measurement. 展开更多
关键词 Fetal Thigh Circumference Fetal Abdominal Subcutaneous Thickness Fetal weight term Pregnancy
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Relationships of Surfactant Head Group Weight Fraction and Some Polarity Terms by Gas Chromatography 被引量:1
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作者 BARAKAT Y MOSTAFA N E +1 位作者 IBRAHIM V MANSOUR R 《色谱》 CAS CSCD 北大核心 2005年第4期341-346,共6页
Polarity, partition coefficient (K), methanol carbon number of surfactant ((CMeOH)S), and methanol carbon number of surfactant head group ((CMeOH)HG) are measured on six alkanolamides and five polyoxyethylenated lon... Polarity, partition coefficient (K), methanol carbon number of surfactant ((CMeOH)S), and methanol carbon number of surfactant head group ((CMeOH)HG) are measured on six alkanolamides and five polyoxyethylenated long chain amines as stationary phases. From the measured methanol carbon numbers, polarity indices, (IP)S and (IP)HG, are calculated. The determined polarity terms are plotted against the head group weight fraction ( fHG ) of the investigated surfactants and several equations have been developed. The study reveals that the molecular structural gap between alkanolamides and polyoxyethylenated long chain amines diminished when HLB numbers of these surfactant classes are plotted against fHG values. Consequently, a general equation relating HLB and fHG is obtained. 展开更多
关键词 气相色谱 表面活性剂 端基 质量分数 极性参数
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The Optimal Weighted Combinational Forecasting with Constant Terms 被引量:1
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作者 ZHANG Jian-guo 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第1期109-113,共5页
我们基于与经常的术语预报的最佳的加权的 combinational 建议一个模型,没有经常的术语,象模型和相应模型的一种关系一样给重量和平均错误的公式,并且比较这些模型。最后,一个例子被给,它证明恰当的精确被提高了。
关键词 常数项 组合预测 加权 优化
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Prevalence of term low birth weight andits determinants in Shanghai, China
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作者 车焱 郭友宁 lqbal Shah 《生殖医学杂志》 CAS 2000年第S1期14-20,共7页
Objective: To investigate the prevalence of term low birth weight (TLBW) and its risk factors. Methods: A follow-up study with 7, 872 couples was conducted from 1987 to 199o beginning from the time they got marriage l... Objective: To investigate the prevalence of term low birth weight (TLBW) and its risk factors. Methods: A follow-up study with 7, 872 couples was conducted from 1987 to 199o beginning from the time they got marriage licenses in two districts defined in Shanghai. They were interviewed in the third month and again in the fifteenth month and in the fifth to sixth year afterwards individually at home. The total follow up rate reached 98%. Couple’s background characteristics as well as the information on their general health. reproductivc history and contraceptive use etc.. were collected dynamically. All of the single live births with term delivery were Included for data analysis in this paper. Adjusted odd ratios and population attributable risk (PAR%) were computed. Results: The prevalence of TLBW in Shanghai single term live births was 2. 0% (134,/6.573), represents 54. 7% (134/245) of the total low birth weights in our sam pie. Significant social and behaviour risk factors relating with TI-BW were wife’s dissat- isfaction with marriage; low education level of husband; co-residence with parents during pregnancy; heavy housework done by the wife while being pregnant. Significant biomedical risky factors were menarche age greater than 16 years old; maternal age at delivery greater than 29 years old; maternal body mass index less than 19. 8; wife suf- fered from serious disease prior to conceiving; having pregnancy complication; gestational weight gain less than 20 % of pre-pregnancy weight; having abortion, stillbirth and fetal death history. Conclusion: TL.BW constituted over half of all low birth weights in Shanghai. Special attention should be paid to the determinants mentioned above in TLBW intervention program. Improving couples’ economic and living condition and husband ’s education at tainment, and caloric supplementation with women while being pregnant would all be particularly effective in reducing the occurrence of TLBW in Shnaghai. 展开更多
关键词 term low birth weight Logistic regression Population attributable risk DEtermINANT
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Changes in weight and metabolic parameters following long-term iloperidone use: A meta-analysis of data from 9 Phase II and III trials of iloperidone
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作者 Marla Hochfeld Saeeduddin Ahmed +1 位作者 Xiangyi Meng Adam Winseck 《Open Journal of Psychiatry》 2012年第4期414-422,共9页
Objective: To determine the impact of iloperidone treatment on metabolic parameters. Methods: Data were analyzed from 3210 patients who received iloperidone and 587 patients who received placebo for up to 2 years duri... Objective: To determine the impact of iloperidone treatment on metabolic parameters. Methods: Data were analyzed from 3210 patients who received iloperidone and 587 patients who received placebo for up to 2 years during 9 Phase II and Phase III studies (integrated safety database). Patients were pooled by most frequent iloperidone dose into 3 groups: 4 - 8 mg/d, 10 - 16 mg/d, and 20 - 24 mg/d. Laboratory data from 8 studies were random (fasting and nonfasting) while patients from 1 study (n = 447) were all sampled at fasting. Results: Mean (standard deviation [SD]) weight gain from baseline to endpoint was 2.1 (6.8) kg for all patients on iloperidone. Fasting mean (SD) total cholesterol changes from baseline to end of study were 8.2 (31.6) for iloperidone and -2.2 (35.2) mg/dL for placebo. Fasting mean (SD) triglyceride changes during this period were iloperidone: -0.83 (82.3);placebo: 16.5 (113.1) mg/dL. Fasting mean (SD) glucose changes were iloperidone: 6.6 (24.0);placebo: -0.05 (17.0) mg/dL from baseline to end of study. Glycosylated hemoglobin levels were unchanged following iloperidone treatment. Conclusion: These data suggest a metabolic profile for iloperidone of modest weight gain accompanied by small changes in lipids and glucose that are unlikely to be of clinical concern. 展开更多
关键词 DYSLIPIDEMIA GLUCOSE ILOPERIDONE LONG-term METABOLIC weight
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Multiple Solutions to the Problem of Kirchhoff Type Involving the Critical Caffareli-Kohn-Niremberg Exponent, Concave Term and Sign-Changing Weights
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作者 Mohammed El Mokhtar Ould El Mokhtar 《Applied Mathematics》 2017年第11期1703-1714,共12页
In this paper, we establish the existence of at least four distinct solutions to an Kirchhoff type problems involving the critical Caffareli-Kohn-Niremberg exponent, concave term and sign-changing weights, by using th... In this paper, we establish the existence of at least four distinct solutions to an Kirchhoff type problems involving the critical Caffareli-Kohn-Niremberg exponent, concave term and sign-changing weights, by using the Nehari manifold and mountain pass theorem. 展开更多
关键词 KIRCHHOFF Type Problems Critical Caffareli-Kohn-Niremberg EXPONENT CONCAVE term Sign-Changing weightS
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基于VMD-改进最优加权法的短期负荷变权组合预测策略
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作者 李志军 徐博 +1 位作者 杨金荣 宁阮浩 《国外电子测量技术》 2024年第2期1-8,共8页
为提升短期电力负荷预测精度,提出了一种变权组合预测策略。首先,为了降低负荷数据的不平稳度,使用变分模态分解(variational mode decomposition,VMD)将负荷数据分解成了高频、低频、残差3种特征模态分量。其次,充分计及负荷数据的时... 为提升短期电力负荷预测精度,提出了一种变权组合预测策略。首先,为了降低负荷数据的不平稳度,使用变分模态分解(variational mode decomposition,VMD)将负荷数据分解成了高频、低频、残差3种特征模态分量。其次,充分计及负荷数据的时序特点,参考指数加权法原理设计自适应误差重要性量化函数,并结合组合模型在时间窗口内的历史负荷数据的均方预测误差设计改进最优加权法的目标函数和约束条件,以完成子模型的准确变权。最后,针对波动较强的高频分量选定极端梯度提升(XGBoost)和卷积神经网络-长短期记忆(CNN-LSTM)模型并使用改进最优加权法进行组合预测、低频分量使用多元线性回归(MLR)模型预测、残差分量使用LSTM模型预测,叠加各模态分量的预测结果,实现了短期负荷数据的准确预测。实验结果表明,使用策略组合模型的平均绝对百分比误差为4.18%。与使用传统组合策略的组合模型相比,平均绝对百分比预测误差平均降低了0.87%。 展开更多
关键词 短期负荷预测 变分模态分解 改进最优加权法 组合模型
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面向语法加权图文本的方面情感三元组抽取
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作者 韩虎 孟甜甜 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2024年第2期409-418,共10页
方面情感三元组抽取包括方面抽取、意见抽取和方面情感分类3项任务,以管道方式解决该任务的研究方法无法利用元素之间的交互信息,同时也会造成错误传播和冗余训练。基于此,提出一种基于门控注意力和加权图文本的方面情感三元组抽取方法... 方面情感三元组抽取包括方面抽取、意见抽取和方面情感分类3项任务,以管道方式解决该任务的研究方法无法利用元素之间的交互信息,同时也会造成错误传播和冗余训练。基于此,提出一种基于门控注意力和加权图文本的方面情感三元组抽取方法。采用双向长短时记忆网络学习句子的序列特征表示;利用门控注意力单元学习单词之间的线性联系;利用语法距离加权图卷积网络增强三元组元素之间的交互;利用网格标记推理策略预测三元组。在4个公开数据集上进行实验,结果表明:所提方法可以有效增强三元组元素之间的交互,提高三元组抽取的准确率;同时,所提方法的F1值分别为57.94%、70.54%、61.95%和67.66%,与基准模型相比均有所提高。 展开更多
关键词 三元组抽取 门控注意力 加权图文本 双向长短时记忆网络 网格标记
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基于分类的term重要性识别方法
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作者 邱云飞 鲍莉 邵良杉 《计算机科学》 CSCD 北大核心 2013年第11期242-247,共6页
在传统的搜索引擎和信息检索中,用户Query中的term-weight通常是以一种上下文无关的方式得到的。现有的大多数信息检索技术都使用词袋方法,例如布尔模型、向量空间模型和概率模型等,这些方法均没有考虑Query中term之间的相关性。为了能... 在传统的搜索引擎和信息检索中,用户Query中的term-weight通常是以一种上下文无关的方式得到的。现有的大多数信息检索技术都使用词袋方法,例如布尔模型、向量空间模型和概率模型等,这些方法均没有考虑Query中term之间的相关性。为了能够充分利用Query中的信息来提高term-weight的准确度,提出了一种有监督的机器学习方法来学习用户Query中的term-weight。该方法基于分类的方法,并引入了句法分析作为分类的一项重要的特征来训练模型。考虑用户Query中term之间的关系后,既避免了由Query到单个term的信息丢失,又增加了短文本的特征,同时使分类器实现软输出,能够给term的重要程度一个更为准确的量化值。 展开更多
关键词 分类 依存句法分析 查询词权重 查询分析 term重要性 搜索引擎 信息检索
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CEEMDAN-WPE-CLSA超短期风电功率预测方法研究
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作者 李杰 孟凡熙 +1 位作者 牛明博 张懿璞 《大连交通大学学报》 CAS 2024年第2期101-108,共8页
提出了一种结合自适应噪声完全集合经验模态分解、加权排列熵、卷积神经网络、长短期记忆网络和自注意力机制的超短期风电功率预测方法。首先,利用自适应噪声完全集合经验模态分解将原始风电功率时间序列自适应分解为一系列的模态分量,... 提出了一种结合自适应噪声完全集合经验模态分解、加权排列熵、卷积神经网络、长短期记忆网络和自注意力机制的超短期风电功率预测方法。首先,利用自适应噪声完全集合经验模态分解将原始风电功率时间序列自适应分解为一系列的模态分量,降低原始序列的非线性和波动性;其次,根据加权排列熵计算各模态分量间的相似性并对相似的分量进行重组,以修正自适应噪声完全集合经验模态分解的过度分解问题,使得修正后的模态分量更具规律性;最后,将重组后的分量输入卷积长短期记忆网络进行时序建模,并利用自注意力机制对卷积长短期记忆网络的神经元权重进行重新分配,提高了卷积长短期记忆网络对输入特征不确定性的适应能力。在此基础上,明确了自注意力机制和自适应噪声完全集合经验模态分解、加权排列熵在风电功率预测中的作用机制,以及风电功率信号包含的重要物理信息,证明了自适应噪声完全集合经验模态分解、加权排列熵以及自注意力机制在风电功率信号模态分解和长短期记忆网络隐层输出权重分配中的有效性。 展开更多
关键词 超短期风电功率预测 自适应噪声完全集合经验模态分解 加权排列熵 卷积长短期记忆网络 自注意力机制
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基于犹豫模糊混合云模型的航空装备保障系统效能评估
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作者 张家贤 涂继亮 +1 位作者 刘辉 叶身辉 《火力与指挥控制》 CSCD 北大核心 2024年第2期18-25,32,共9页
针对航空装备保障系统效能评估过程存在定性指标与定量指标共存、评价信息具有不确定性等问题,提出了一种基于犹豫模糊混合云模型的效能评估方法。根据语言变量的转换与正态云模型之间的混合规则,将犹豫模糊语言术语集转换为梯形云模型... 针对航空装备保障系统效能评估过程存在定性指标与定量指标共存、评价信息具有不确定性等问题,提出了一种基于犹豫模糊混合云模型的效能评估方法。根据语言变量的转换与正态云模型之间的混合规则,将犹豫模糊语言术语集转换为梯形云模型,并根据云模型的数字特征,提出了犹豫模糊语言术语集的犹豫度函数与标度函数,实现了对定性指标的量化,兼顾了评价信息的犹豫性、模糊性和随机性。利用区间层次分析法结合灰狼优化算法对效能评估指标体系进行权重赋值,确定系统效能等级。通过应用实例与方法比较表明:犹豫模糊混合云模型不仅评估结果可靠,而且能够识别系统的运行状态,发现系统建设的短板,为提高系统效能提供重要的参考意见,更具有实用性。 展开更多
关键词 航空装备保障 效能评估 犹豫模糊语言术语集 混合云模型 联合权重赋值
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基于多视图与注意力机制的睡眠脑电分期
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作者 李兰亭 苗敏敏 《国外电子测量技术》 2024年第1期30-37,共8页
为了更全面地对睡眠脑电进行特征提取,提出一种基于多视图与注意力机制的睡眠脑电分期方法。首先针对原始睡眠脑电信号构造时域和时频域两类视图数据;然后设计融合注意力机制的混合神经网络对多视图数据进行表征学习;接着通过双向长短... 为了更全面地对睡眠脑电进行特征提取,提出一种基于多视图与注意力机制的睡眠脑电分期方法。首先针对原始睡眠脑电信号构造时域和时频域两类视图数据;然后设计融合注意力机制的混合神经网络对多视图数据进行表征学习;接着通过双向长短时记忆(bi-directional long short-term memory,BiLSTM)网络进一步学习睡眠阶段之间的转换规则;最后使用Softmax函数进行睡眠分期,并利用类别加权损失函数解决睡眠数据类别不均衡的问题。实验使用Sleep-EDF数据库中前20名受试者的单通道脑电信号并采用20折交叉验证对模型进行性能评估,睡眠分期准确率达到83.7%,宏平均F_(1)值达到79.0%,Cohen′s Kappa系数达到0.78。与现有方法相比,算法性能提升明显,证明了所提方法的有效性。 展开更多
关键词 睡眠分期 多视图 注意力机制 双向长短时记忆网络 类别加权损失函数
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妊娠糖尿病患者孕期体质量变化与母婴不良结局的关系研究
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作者 彭格 卢静 黄亚琴 《当代医学》 2024年第1期51-54,共4页
目的探讨妊娠糖尿病(GDM)患者孕期体质量变化与母婴不良结局的关系。方法选取2020年1月至2021年12月监利市中医医院产科收治的80例GDM患者作为研究对象,根据体重指数(BMI)不同分为体质量正常组(n=32)、超重组(n=28)及肥胖组(n=20)。比较... 目的探讨妊娠糖尿病(GDM)患者孕期体质量变化与母婴不良结局的关系。方法选取2020年1月至2021年12月监利市中医医院产科收治的80例GDM患者作为研究对象,根据体重指数(BMI)不同分为体质量正常组(n=32)、超重组(n=28)及肥胖组(n=20)。比较3组临床资料,采用Spearman相关性分析GDM患者孕期体质量变化与不良母婴结局的关系,采用多因素Logistic回归分析孕期体质量变化的影响因素。结果3组孕前体质量、孕期血糖控制效果、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、孕期是否接受过饮食及运动干预比较差异有统计学意义(P<0.05);3组年龄、学历、孕次、孕龄、高密度脂蛋白胆固醇(HDL-C)、稳态模型评估-胰岛素抵抗指数(HOMA-IR)比较差异无统计学意义。体质量正常组巨大儿发生率、胎儿宫内窒息发生率、产妇出血率均低于超重组及肥胖组,差异有统计学意义(P<0.05)。Spearman相关性分析结果显示,GDM患者孕期体质量变化与足月巨大儿发生率呈正相关(r>0,P<0.05),而与胎儿宫内窒息发生率、产妇出血率无明显相关性。多因素Logistic回归分析结果显示,孕前体质量高、孕期血糖控制效果不佳、TG高水平、LDL-C高水平是GDM患者孕期体质量增长的危险因素(P<0.05),而孕期进行饮食及运动干预是GDM产妇孕期体质量增加的保护因素(P<0.05)。结论GDM患者孕期肥胖与足月巨大儿发生率呈正相关,孕期加强饮食及运动干预有助于控制患者体质量增长,减少不良母婴结局。 展开更多
关键词 妊娠糖尿病 孕期体质量 足月巨大儿 影响因素
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RESEARCH ON WEIGHTED PRIORITY OF EXEMPLAR-BASED IMAGE INPAINTING 被引量:28
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作者 Zhou Yatong Li Lin Xia Kewen 《Journal of Electronics(China)》 2012年第1期166-170,共5页
The priority of the filled patch play a key role in the exemplar-based image inpainting, and it should be determined firstly to optimize the process of image inpainting. A modified image inpainting algorithm is propos... The priority of the filled patch play a key role in the exemplar-based image inpainting, and it should be determined firstly to optimize the process of image inpainting. A modified image inpainting algorithm is proposed by weighted-priority based on the Criminisi algorithm. The improved algorithm demonstrates better relationship between the data term and the confidence term for the optimization of the priority than the classical Criminisi algorithm. By comparing the effect of the inpainted images with different structure, conclusion can be drawn that the optimal priority should be chosen properly for different images with different structures. 展开更多
关键词 Image inpainting Exemplar-based Data term PRIORITY weight
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基于考虑误差修正的非线性自适应权重组合模型的光伏发电功率预测
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作者 陈德余 张玮 王辉 《济南大学学报(自然科学版)》 CAS 北大核心 2024年第2期250-256,共7页
为了提高光伏电站光伏发电功率预测精度,解决极限梯度提升模型、长短期记忆模型2种传统单一模型及传统组合模型极限梯度提升-长短期记忆模型的光伏发电功率预测结果滞后、预测效果易突变、预测误差较大、线性拟合性较差等不足,基于极限... 为了提高光伏电站光伏发电功率预测精度,解决极限梯度提升模型、长短期记忆模型2种传统单一模型及传统组合模型极限梯度提升-长短期记忆模型的光伏发电功率预测结果滞后、预测效果易突变、预测误差较大、线性拟合性较差等不足,基于极限梯度提升算法、长短期记忆算法和线性自适应权重,提出一种考虑误差修正的非线性自适应权重极限梯度提升-长短期记忆模型进行光伏发电功率预测;分别使用极限梯度提升算法和长短期记忆算法训练得到2种单一模型,将2种单一模型的初步预测值和真实值组成新的训练数据集,利用神经网络算法训练所提出的模型,对2种单一模型的初步预测值分配自适应权重系数,并根据训练时所提出模型的预测值大小分段统计预测误差的分布,预测时根据所提出模型的预测值在预测结果的基础上累加误差均值从而进行误差修正,进一步提高所提出模型的预测精度;利用Python语言分别对所提出的模型、传统组合模型和2种传统单一模型在晴天、阴天和雨天的光伏发电功率预测性能进行仿真。结果表明:与极限梯度提升-长短期记忆模型、极限梯度提升模型、长短期记忆模型相比,所提出模型的均方根误差分别减小28.57%、 39.39%、 49.79%,平均绝对误差分别减小44.25%、 53.33%、 64.8%,决定系数分别增大1.43%、 2.38%、 3.34%,所提出的模型更有效地减小了传统单一模型的光伏发电功率预测误差,优化了传统组合模型的权重系数;3种天气条件下所提出模型的光伏发电功率预测误差相对最小且稳健性最强,验证了所提出模型的有效性。 展开更多
关键词 光伏发电 功率预测 自适应权重 误差修正 极限梯度提升算法 长短期记忆算法
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基于增量学习的CNN-LSTM光伏功率预测
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作者 严璐晗 林培杰 +2 位作者 程树英 陈志聪 卢箫扬 《电气技术》 2024年第5期31-40,共10页
针对目前大部分光伏功率预测模型采用批量离线训练方式,且新建光伏电站训练数据较少的问题,本文提出一种基于增量学习的卷积神经网络(CNN)和长短期记忆(LSTM)网络结合的光伏功率预测模型。首先,采用CNN对气象数据进行特征提取,并通过LST... 针对目前大部分光伏功率预测模型采用批量离线训练方式,且新建光伏电站训练数据较少的问题,本文提出一种基于增量学习的卷积神经网络(CNN)和长短期记忆(LSTM)网络结合的光伏功率预测模型。首先,采用CNN对气象数据进行特征提取,并通过LSTM网络进行功率预测,以此CNN-LSTM混合模型进行背景学习,训练出可用于增量学习的基准模型。其次,根据不同的时间跨度进行增量学习训练,实现模型的在线更新。针对增量学习中的灾难性遗忘问题,采用弹性权重整合(EWC)算法和在线弹性整合(Online_EWC)算法进行缓解。实验结果表明,相较于无约束的增量学习,采用EWC和Online_EWC方法的增量学习可以明显缓解灾难性遗忘问题,降低预测平均绝对误差(MAE)和均方根误差(RMSE);同时,在保证预测精度的前提下,增量学习的耗时大幅低于传统的批量学习。 展开更多
关键词 光伏功率预测 长短期记忆(LSTM)网络 增量学习 弹性权重整合(EWC)算法
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肝素钠联合地屈孕酮治疗先兆流产的临床效果
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作者 吴海荣 李婕 《中外医疗》 2024年第4期75-78,共4页
目的分析肝素钠联合地屈孕酮治疗先兆流产的临床效果。方法回顾性选取2021年4月-2022年11月枣庄市妇幼保健院妇产科接诊的94例先兆流产妊娠期妇女的病历资料,按照用药方案分为两组,每组47例。参照组口服地屈孕酮片,研究组联用低分子肝... 目的分析肝素钠联合地屈孕酮治疗先兆流产的临床效果。方法回顾性选取2021年4月-2022年11月枣庄市妇幼保健院妇产科接诊的94例先兆流产妊娠期妇女的病历资料,按照用药方案分为两组,每组47例。参照组口服地屈孕酮片,研究组联用低分子肝素钠注射液,比较用药后子宫流血、腰腹疼痛消失时间、孕酮恢复时间、血样指标、不良反应发生率、保胎率等。结果研究组保胎率(95.74%)比参照组(80.85%)高,差异有统计学意义(χ^(2)=5.045,P=0.025);研究组用药后子宫流血、腰腹疼痛消失时间和孕酮恢复时间均短于参照组,差异有统计学意义(P均<0.05);研究组的不良反应发生率(4.25%)与参照组(8.51%)相比,差异无统计学意义(P>0.05);研究组治疗后纤维蛋白原、D-二聚体、超敏C-反应蛋白等指标改善优于参照组,差异有统计学意义(P均<0.05)。结论对先兆流产患者联合使用低分子肝素钠与地屈孕酮诊治其疗效显著,具有较大的临床借鉴价值。 展开更多
关键词 先兆流产 低分子肝素钠 地屈孕酮 临床效果 联合用药 足月妊娠
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The effect of weight loss on fasting blood sugars and hemoglobin A1c in overweight and obese diabetics and non-diabetics
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作者 James Stanford Matthew Kaiser +3 位作者 Elizabeth Ablah Frank Dong Bobbie Paull-Forney James Early 《Journal of Diabetes Mellitus》 2012年第1期126-130,共5页
BACKGROUND: Diet and exercise are recommended first line treatment for overweight, obese, and diabetic patients with the goal of decreasing weight and improving glycemic control. The goal of this study was to determin... BACKGROUND: Diet and exercise are recommended first line treatment for overweight, obese, and diabetic patients with the goal of decreasing weight and improving glycemic control. The goal of this study was to determine the effect that a low calorie diet and behavioral modification program, as implemented by a medically supervised weight loss program, would have on the fasting blood sugar and hemoglobin A1c in overweight or obese diabetic and over-weight or obese non-diabetic participants. METHODS: Charts from 2009 to 2010 were reviewed for 310 diabetic and non-diabetic patients enrolled in the Via Christi Weight Management (VCWM) program in Wichita, Kansas. Data were collected before and after patients underwent a program of meal replacements and weekly physical activity lasting 12 weeks. Variables included pre and post treatment fasting blood sugars, hemoglobin A1c, body mass index, percent body weight lost, and diabetes status. RESULTS: Diabetic participants lost an average of 11.7% of their initial body weight (IBW), and non-diabetic patients lost 12.5% of their IBW over the treatment course. Post-treatment average fasting blood glucose (FBG) decreased in both diabetics and non-diabetics by 15.53 mg/dL and 8.46 mg/dL, respectively (p = 0.08). Diabetic patients experienced a significant decrease of 0.83% from pre to post-treatment in hemoglobin A1c. For diabetic and non-diabetic groups, the changes in FBG were correlated with the change in weight. CONCLUSIONS: Diet and exercise, as prescribed by the VCWM program, is effective in reducing hemoglobin A1c in diabetics and reducing fasting blood sugars in both diabetic and non-diabetic patients. 展开更多
关键词 Long-term weight Maintenance Hypertension Diabetes HEMOGLOBIN A1C Low-Energy Diets
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