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1.
从特征参数提取角度出发,提出了一种基于高阶累积量和瞬时特征的信号调制识别算法。该算法从调制信号高阶累积量中提取出稳健的特征参数,并结合改进的瞬时特征参数,采用决策树的方法对信号进行调制识别。与传统决策论识别算法相比,本算法特征参数较少,识别类型多。最后仿真结果表明,该算法在较低信噪比下具有很好的识别率(〉95%)。  相似文献   

2.
提出一种基于眼睛状态识别的驾驶员疲劳状态检测的方法。首先通过建立肤色模型分割出人脸区域,再利用搜索连通域的方法实现眼睛区域的定位;然后计算出眼睛区域的垂直积分投影曲线,提取并比较曲线的特征参数,从而识别眼睛的状态;最后以眼睛闭合时间比率为测量标准实现对驾驶员疲劳程度的检测。实验表明,该方法简单、有效、实时性较好,疲劳检测的正确率较高。  相似文献   

3.
冕环是太阳大气中的炙热等离子在太阳磁场的作用下产生的一种太阳特征结构;研究冕环动力学特征将促进我们对太阳日冕磁场,日冕加热和日冕振荡等研究.冕环结构的准确识别和提取则是相关研究的前提条件.然而由于日冕磁场的复杂性,使得对冕环结构识别和提取面临很大的困境.为此,本文提出了一个新的冕环识别算法.该算法结合了引导滤波和小波变换模极大值的方法来对冕环结构进行自动识别和提取.识别和提取算法过程如下:(1)运用模糊函数对太阳日冕图像的对比度进行增强;(2)使用引导滤波对增强后的图像进行滤波来增强冕环结构的边缘;(3)对滤波过后的图像使用小波变换模极大值法来识别图像中的冕环结构,并对识别出的冕环图像进行二值化处理;(4)对二值化图像进行形态学处理来获取冕环结构.运用该算法对由过渡区和日冕探测器(Transition and Coronal Explorer, TRACE)和太阳动力观测站的大气成像装置(Atmospheric Imaging Assembly on the Solar Dynamics Observatory, SDO/AIA)观测设备在171?波段所观测的日冕图像中的冕环结构进行识别和提取,并同已有文献的识别结果进行了对比,结果表明本文所提出的算法具有很高的识别率和很好的鲁棒性.所识别和提取的冕环结构能进一步用于科学研究中.  相似文献   

4.
合成孔径雷达自动目标识别是合成孔径雷达的一个重要的应用方面,如何在高维SAR图像中提取有效分类信息是制约自动目标识别的瓶颈问题.本文基于流形结构假设,提出了一种新的特征提取方法——最大异类距离特征提取,该方法融入了样本集类别信息和邻域信息,通过最大化异类样本的距离实现特征提取,以提高特征的可鉴别性.基于MSTAR数据库的实验已验证了本文提出的方法能够有效提高目标识别率.  相似文献   

5.
目的建立并优化姜黄素逆转人结肠癌细胞HCT-8/VCR蛋白质纽的双向电泳技术。方法姜黄素作用于人结肠癌细胞HCT-8/VCR,提取蛋白质。对双向凝胶电泳中蛋白质样品的处理,蛋白上样量,IPG胶条的选择,以及聚焦条件等进行调整和每化。结果采用瓶内刮取的方法裂解细胞,pH3-10NL的胶条,上样量200ug,延长除盐时间,聚焦60000伏小时,可以得到分辨率较高、重复性较好的双向电泳图谱。结论初步建立了分辨率较高且重复性较好的姜黄素逆转人结肠癌细胞HCT-8/VCR蛋白质双向凝胶电泳图谱。  相似文献   

6.
基于奇异熵定阶降噪的水工结构振动模态ERA识别方法   总被引:3,自引:0,他引:3  
针对原型动力试验激励难的问题,结合水工结构在工作状态下环境激励荷载的特点,直接根据水工结构在工作环境激励荷载作用下的动力响应识别结构的动力特性,提出一种利用特征矩阵奇异熵对信号进行降噪、重构、定阶以及模态参数识别的方法,解决了系统特征矩阵定阶难的问题,揭示了结构在工作状态下的模态阶次及模态特性。最后将该方法应用于二滩拱坝在不同泄洪工况下的模态参数识别以及李家峡双排机厂房在停机过程中的结构振动频率识别。该方法的提出,为解决大型水工结构在工作环境激励下的模态参数识别问题提供了捷径。  相似文献   

7.
针对X射线造影(XRA)图像的分割,首先分析了血管图像的基本特征和先验知识,提出血管结构的多特征模糊识别(MFFR)算法;然后提出基于先验知识引导的概率跟踪算子(PTO),该算子能够迅速地跟踪动脉血管树,并能够跨过因干扰或预处理导致的血管局部消弱和断裂区域.另外,跟踪过程中同步地进行了血管中心线和宽度的精确测量.为正确评价该方法,分别利用真实造影图像和二维仿真动脉树进行实验评估,结果表明该方法较传统方法高效,一次选定跟踪的起点,平均92.7%的可见血管段或分支可以自动提取出来,结构识别正确率平均达到90.0%.  相似文献   

8.
通过将ANN(人工神经网络)改进应用到HMM(隐马尔科夫模型),使用Mel频率倒谱系数(MFCC)+帧能量+MFCC一阶差分,二阶差分的结构提取咳嗽音特征参数,HMM输出的所有状态累积概率作为ANN的输入序列进行非线性映射,进而提取新的信息来提高HMM的识别性能.实验证明,利用HMM-ANN混和模型来处理咳嗽声识别具有更高的识别精度和可靠性.  相似文献   

9.
在分析我国大型工程建设项目风险特征的基础上,构建项目风险识别框架。并通过因子分析识别出自然环境、技术、组织管理、资源管理、分包商管理、环保等6方面是大型工程建设项目的关键风险因素。此外,还研究了大型工程建设项目关键风险因素的作用机理及作用模型,并采用结构方程模型检验。  相似文献   

10.
线性定常系统特征模型的证明   总被引:3,自引:0,他引:3  
孟斌  吴宏鑫 《中国科学(E辑)》2007,37(10):1258-1271
研究线性定常系统的特征建模问题,证明了多输入多输出线性定常系统的特征模型可以用二阶时变差分方程组描述,并且刻画了特征模型的建模误差,在系统不含零实部极点的情形下,在稳态和暂态时建模误差分别为0和O(h),一般情形下,分别为O(h^2)和D(h).该证明表明特征建模与一般模型降阶方法是本质不同的,特征模型是把高阶模型的有关信息压缩到几个特征参量之中,并没有丢失系统信息.  相似文献   

11.
Human colon adenocarcinomas from 52 patients were investigated for the presence of the colon polymorphic antigens WZ. The patients were typed for their WZ phenotype, using the immunofluorescence method on non tumoral colon mucosa sections: 27 patients were found W+ Z+, 18 W- Z+, and 7 W- Z-. The tumors were tested for the presence of the WZ phenotypes, using the immunofluorescence method and a radio-immunoassay. The WZ phenotypes were not expressed in the non secreting tumors, whatever the patient's phenotype. They were expressed in the secreting tumors and had the same phenotype as found in the corresponding normal mucosa. The WZ phenotypes were present in human developed into "nude" Mice inoculated either with differentiated colon carcinomas, or with a human colon carcinoma cell line (HT-29).  相似文献   

12.
F Herz 《Experientia》1989,45(8):753-755
The continuous cell lines T 24 and HT-29, derived from human bladder and colon carcinomas, produce term-placental and intestinal alkaline phosphatase, respectively. Growth in hyperosmolar medium or exposure to prednisolone or sodium butyrate induces increased enzyme levels, and combinations of inducers elicit synergistic activity increases. The effect of the inducing agents is strikingly diminished when cells are grown in the presence of high concentrations of human serum, and the synergistic increases are essentially abolished. Major human serum protein fractions do not affect alkaline phosphatase induction.  相似文献   

13.
Summary The continuous cell lines T 24 and HT-29, derived from human bladder and colon carcinomas, produce term-placental and intestinal alkaline phosphatase, respectively. Growth in hyperosmolar medium or exposure to prednisolone or sodium butyrate induces increased enzyme levels, and combinations of inducers elicit synergistic activity increases. The effect of the inducing agents is strikingly diminished when cells are grown in the presence, of high concentrations of human serum, and the synergistic increases are essentially abolished. Major human serum protein fractions do not affect alkaline phosphatase induction.  相似文献   

14.
目的 探讨人子宫颈癌中负性协同刺激分子PD-L1的表达和它与肿瘤浸润淋巴细胞的关系以及PD-L1融合蛋白促宫颈癌患者外周血活化T细胞凋亡的作用.方法 采用免疫组化S-P法检测67例宫颈癌组织及20例正常宫颈组织中PD-L1的表达,分析PD-L1同临床病理特征的相关性,免疫荧光观察肿瘤浸润淋巴细胞数量,TUNEL法检测T细胞凋亡,体外实验将PD-L1融合蛋白细胞加入PHA刺激活化的宫颈癌患者外周血T细胞中共同培养,流式细胞术分析T细胞凋亡率和CD8+/CD4+T细胞比例.结论 正常子宫颈组织不表达PD-L1;宫颈癌组织中PD-L1的表达率为70%.宫颈癌PD-L1的表达与宫颈癌浸润深度相关(P<0.05).PD-L1阳性病例肿瘤局部浸润淋巴细胞存在凋亡且CD8+T细胞数量明显减少;PD-L1融合蛋白组T细胞凋亡率明显高于抗PD-1组和空白对照组T细胞,分别为32.7%、18.3%和17.9%;CD8+T/CD4+T细胞的比值低于加入抗PD-1组和空白对照组,分别为0.864、0.894和0 907.结论 PD-L1在子宫颈癌中高表达且与肿瘤浸润程度及肿瘤浸润淋巴细胞数量减少有关,PD-L1能促进活化的T细胞尤其是CD8+T细胞的凋亡.  相似文献   

15.
Altered proteoglycan gene expression and the tumor stroma   总被引:4,自引:0,他引:4  
Tumor stroma is a specialized form of tissue that is associated with epithelial neoplasms. Recent evidence indicates that significant changes in proteoglycan content occur in the tumor stroma and that these alterations could support tumor progression and invasion as well as tumor growth. Our main hypothesis is that the generation of tumor stroma is under direct control of the neoplastic cells and that, via a feedback loop, altered proteoglycan gene expression would influence the behavior of tumor cells. In this review, we will focus primarily on the work from our laboratory related to the altered expression of chondroitin sulfate proteoglycan and its role in tumor development and progression. The connective tissue stroma of human colon cancer is enriched in chondroitin sulfate and the stromal cell elements, primarily colon fibroblasts and smooth muscle cells, are responsible for this biosynthetic increase. These changes can be reproduced in vitro by using either tumor metabolites or co-cultures of human colon carcinoma cells and colon mesenchymal cells. The levels of decorin, a leucine-rich proteoglycan involved in the regulation of matrix assembly and cell proliferation, are markedly elevated in the stroma of colon carcinoma. These changes correlate with a marked increase in decorin mRNA levels and a concurrent hypomethylation of decorin gene, a DNA alteration associated with enhanced gene expression. Elucidation of decorin gene structure has revealed an unexpected degree of complexity in the 5 untranslated region of the gene with two leader exons that are alternatively spliced to the second coding exon. Furthermore, a transforming growth factor beta (TGF-)-negative element is present in the promoter region of decorin gene. This regulatory domain is likely to be implicated in the silencing of decorin gene by TGF- and may contribute to the regulation of this matrix gene in the tumor stroma.  相似文献   

16.
Empirical agreement is often used as an important criterion when assessing the validity of scientific models. However, it is by no means a sufficient criterion as a model can be so adjusted as to fit available data even though it is based on hypotheses whose plausibility is known to be questionable. Our aim in this paper is to investigate into the uses of empirical agreement within the process of model validation.  相似文献   

17.
Rabbit antisera raised against a strain of E. coli 013, with a strong antiglycogen activity, were tested on human fetal and normal adult colons, on colon carcinomas, and on colon tumor cells in culture (HT29). Only very rare granules were present in adult normal colons when tested with the immunofluorescence method. In faetal colons, in 12 out of 14 carcinomas, and on HT29 cells, the immunofluorescent reactions were similar to those observed in normal liver. The reactions were negative after previous treatment with alpha-amylase. They were inhibited with glycogen, with phenol-alcohol, perchloric, and trichloroacetic extracts from faetal colons, and with a tumor trichloroacetic extract. The extracts precipitated with anti-E. coli 013 antisera. They had a strong inhibiting activity in a radioimmunoassay test with labeled glycogen. The extracts from normal adult colons did not precipitate with the antisera and they had no inhibiting activity in either immunofluorescence and radioimmunoassay tests.  相似文献   

18.
Rat liver microsomes and homogenized mucosal linings prepared from vitamin A-supplemented and deficient male rats were used in metabolic studies of 7-3H-styrene oxide. The colon tissue in deficient animals exhibits a significantly higher value of Vmax than the same tissue from vitamin-supplemented animals. The implications of this finding in addition to our earlier observation 10 is discussed in relation to colon carcinoma.  相似文献   

19.
Detection of the H-RAS oncogene in human thyroid anaplastic carcinomas   总被引:1,自引:0,他引:1  
We have transfected high-molecular-weight DNA from human thyroid carcinomas into murine 3T3 cells. As a result we identified several foci of morphologically distinct transformed cells in each of the tumour DNA transfected cultures. After a total of three rounds of transfection, the transformed cells were shown to form tumours in nude mice. Southern blot analysis of DNA prepared from third-round transfectants demonstrated the presence of human Alu repetitive sequences and, after hybridization with probes for known oncogenes, indicated the presence of the human H-RAS oncogene in 3T3 cells transfected with three out of four anaplastic carcinoma DNA samples. It appears therefore that activation of RAS genes may be an important event in the development of the anaplastic thyroid tumours.  相似文献   

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