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1.
针对脑肿瘤磁共振图像分类问题中过拟合及分类准确率较低的问题,提出一种基于改进EfficientNetV2网络的脑肿瘤分类方法.该方法在EfficientNetV2网络中引入坐标注意力机制,该注意力机制将同时从垂直和水平两个方向获取脑肿瘤的特征信息,精准识别脑肿瘤的病灶特征,从而帮助模型更全面、准确地定位和识别病灶区域信息,有效抑制背景信息对检测结果的影响,使模型分类精度更高,解决了因获取特征信息不足导致分类精度低的问题.为进一步提升分类准确率,引入Hard-Swish激活函数,该激活函数不仅可以提升脑肿瘤分类网络模型的运算速度,也可有效提高分类精度.同时,改进后的模型搭配了Dropout层和归一化层,可更好抑制过拟合的发生,加快模型收敛速度,提高模型的鲁棒性,且分类精度有明显提升.实验结果表明,改进后的模型在验证集中获得了98.4%的分类准确率,通过对比实验和消融实验验证了改进后的模型在脑肿瘤分类任务中的有效性.  相似文献   

2.
针对糖尿病视网膜眼底病变多类分割难及小病灶识别率低的问题,提出一种融合注意力机制与改进型DeepLabV3+的糖尿病视网膜眼底病变多类病症分割方法.该方法首先通过使用MobileNetV2网络提取病灶特征,减少参数量并提高算法训练速度;接着通过优化空洞空间卷积金字塔池化中的空洞卷积层数与空洞率,以提高捕获小病灶特征的能力;然后基于DeepLabV3+网络模型进行改进,借助坐标注意力机制感知病灶方向和位置信息,从而提高识别精度;最后采用FGADR和IDRiD数据集分别训练和测试所提出的模型.实验结果表明:所提出方法的平均交并比(MIoU)指标为73.75%,具有较高的分割精度,验证了模型有效性.  相似文献   

3.
计算预测蛋白质磷酸化位点的方法常用于位点识别的初筛阶段。为了提升位点初筛的准确率,本文提出一个深度学习模型MAPhos。该模型首先运用氨基酸向量与位置向量的和表示每一个氨基酸残基;随后使用双向GRU循环神经网络捕获各氨基酸残基的特征;接着引入多头注意力机制计算各注意力头的子上下文向量,并将它们连接起来构成肽段的上下文向量;最后通过一个全连接神经网络进行非线性变换和结果预测。真实数据集上的实验结果表明,MAPhos模型预测磷酸化位点在AUC值、灵敏度、正确率、精度和F1分数统计度量上胜过基于特征提取的模型和基于卷积神经网络的模型,同时与基于卷积神经网络的模型相比具有更好的可解释性,这证明了MAPhos模型更加适用于磷酸化位点识别任务的初筛阶段。  相似文献   

4.
为提升大坝结构变形预测精度,采用完全自适应噪声集合经验模态分解(CEEMDAN)法将变形实测序列解耦为一系列具有不同时频特征的本征模态函数,使用小波阈值消噪对高频分量平稳化处理后进行重构,利用基于双阶段注意力机制的长短期记忆网络(DA-LSTM)模型对重构变形序列进行预测。实例验证结果表明,联合CEEMDAN算法和小波阈值消噪方法能够有效识别并清洗实测数据中的异常值,提升了测值对大坝运行性态的表征能力,同时DA-LSTM模型可以充分挖掘大坝变形的滞后性和增强网络的可解释性,据此构建的变形预测模型具有优良的稳健性。  相似文献   

5.
杨磊  赵红东 《科学技术与工程》2020,20(33):13757-13761
环境声音识别(Eenvironment Ssound Rrecognition ,ESR)在基于情景感知和辅助技术等领域发挥着重要作用。卷积神经网络(CNN)和循环神经网络(RNN)作为两种最具代表性的特征提取方法,在语音和音乐信号处理方面都取得显著效果,然而二者都存在一定缺点,CNN无法有效提取时间特征,RNN在提取空间特征上也存在明显劣势。为了有效的提取并利用时间特征和空间特征,提出一种新模型,利用时间分布卷积神经网络(CNN)从梅尔频谱图中提取城市环境声音特征,然后应用双向长短时记忆网络(BiLSTM)从CNN输出中获取时间信息,最后在BRNN的输出序列上实施注意力机制,从而关注到与城市环境声音最相关的特征进而做出分类判断,注意力机制既提高了分类准确性,又增强了模型的可解释性。实验结果表明,在Urbansound8K数据集中,该模型可获得80.2%的分类准确率,这优于以前在同一数据集的报告结果  相似文献   

6.
为解决已有复述语义计算方法未考虑句法结构的问题, 提出基于句法结构的神经网络复述识别模型, 设计基于树结构的神经网络模型进行语义组合计算, 使得语义表示从词语级扩展到短语级。进一步地, 提出基于短语级语义表示的句法树对齐机制, 利用跨句子注意力机制提取特征。最后, 设计自注意力机制来增强语义表示, 从而捕获全局上下文信息。在公开英语复述识别数据集Quora上进行评测, 实验结果显示, 复述识别性能得到改进, 达到89.3%的精度, 证明了提出的基于句法结构的语义组合计算方法以及基于短语级语义表示的跨句子注意力机制和自注意力机制在改进复述识别性能方面的有效性。  相似文献   

7.
动物种类的识别一直是图像识别领域的重点,为了更好地对图像中动物进行识别、帮助社会对家庭宠物的管理,本论述提出一种基于ACNet模块和CBAM注意力机制模块而改进的ACResNet18模型用来识别猫狗种类,通过非对称卷积快增强网络模型的核骨架,实现更有效的特征提取,引入CBAM注意力机制加强网络识别精度,能够更精确地对图像中猫狗进行识别和分类。本次实验使用Kaggle竞赛中的猫狗数据集进行图像识别,并通过对比实验,验证了相比于原模型,改进后的模型准确率有明显提升,最终提高了模型在图像分类上的精确度和鲁棒性,证实了该模型的可靠性。  相似文献   

8.
将深度学习应用于行人重识别领域,嵌入多尺度注意力融合模块至神经网络中进行多尺度特征提取和表示,可有效提升注意力机制对深度学习网络的识别性能。提出了一种基于SE block的多尺度通道注意力融合模块,并结合ResNet50卷积神经网络提取特征;然后通过双向LSTM网络进一步提取特征序列上下文信息,在提高模型对图像重要特征的提取能力的同时,降低对图像冗余特征的关注度;最后使用级联难采样三元组损失函数和交叉熵损失函数共同训练网络模型,使样本能够在高维特征空间中实现聚类,进一步提升模型识别准确性。所提出算法在Market1501数据集和CUHK03数据集分别进行实验,并在同等条件下和其他注意力模块算法进行比较。为进一步验证各模块作用,对算法进行消融实验,以验证各模块的有效性,实验结果表明,所提出方法可有效应用于行人重识别  相似文献   

9.
针对目前的行人属性识别方法存在鲁棒性差、特征表达能力不足和行人的细粒度特征识别精度不高的缺点,提出一种基于注意力机制与空间金字塔池化的行人属性识别方法,通过注意力机制强化不同维度的特征,提升行人整体特征表达;通过空间金字塔池化操作,实现任意大小图像的输入,更好地保留图像的特征信息。结果表明,与现有的其他方法相比,所提出的行人属性识别方法可以精确地识别行人多种属性,具有较高的行人细粒度特征识别精度。  相似文献   

10.
快速准确的火焰检测对于降低火灾危害具有重要意义,为了加强模型的火焰特征提取能力以及解决特征图尺寸不平衡的问题,利用XSepConv (Extremely Separated Convolution)、大卷积核、Mish激活函数等构建CXANet-block(ConvolutionExtremelyAttentionNetwork)作为YOLOv5的骨干网络,引入CBAM (ConvolutionBlockAttention Module)注意力机制,提出一种基于CXANet-YOLO的火焰检测方法,通过增加通道注意力和空间注意力来提高检测性能.在自建火焰数据集上进行训练,提升模型的鲁棒性和泛化能力.实验结果表明,CXANet-YOLO模型比基准模型YOLOv5在火焰检测上具有更高的检测精度和检测速度,准确率提高了8.2%,检测速度每秒提升25帧.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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