期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
胃低级别上皮内瘤变根除幽门螺杆菌后病理升级的危险因素列线图建立与验证 被引量:2
1
作者 朱岳升 夏豫珊 +5 位作者 阮烨娇 李佳佳 史宇宁 张徐弨 朱正 卢光荣 《中国内镜杂志》 2022年第8期47-53,共7页
目的建立并验证胃低级别上皮内瘤变(LGIN)根除幽门螺杆菌(HP)感染后病理升级的危险因素列线图。方法选取该院消化内科初诊胃镜活检病理提示为胃LGIN的患者,予以根除HP,并对其进行2年的随访,统计分析病理升级组和未升级组之间临床和内镜... 目的建立并验证胃低级别上皮内瘤变(LGIN)根除幽门螺杆菌(HP)感染后病理升级的危险因素列线图。方法选取该院消化内科初诊胃镜活检病理提示为胃LGIN的患者,予以根除HP,并对其进行2年的随访,统计分析病理升级组和未升级组之间临床和内镜特征的差异,通过单因素和多因素分析筛选出有明显差异的独立危险因素,建立胃LGIN病理升级的危险因素列线图模型,并利用C指数、受试者操作特征曲线(ROC)和校正图,予以验证列线图的稳定性及可靠性。结果共纳入309例患者。其中,有153例发生了病理升级。单因素分析表明,性别、病灶直径、有无边界、病灶数量、形状及是否伴有糜烂溃疡差异有统计学意义;而多因素分析表明,患者为男性、病灶直径≥1 cm、有边界和凹陷型且无糜烂溃疡是发生病理升级的独立危险因素。建立列线图后,验证该模型C指数为0.775(0.724~0.826),ROC曲线的曲线下面积(AUC)为0.740,且校正图显示该模型有较好的稳定性。结论该模型具有较好的稳定性和一致性,可用于评估胃LGIN患者中根除HP后发生病理升级的风险大小,指导临床选择合适的治疗方式。 展开更多
关键词 胃低级别上皮内瘤变 根除幽门螺杆菌 危险因素 列线图
下载PDF
A robust watermarking algorithm based on QR factorization and DCT using quantization index modulation technique 被引量:1
2
作者 Hong-yuan CHEN yue-sheng zhu 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2012年第8期573-584,共12页
We propose a robust digital watermarking algorithm for copyright protection.A stable feature is obtained by utilizing QR factorization and discrete cosine transform(DCT) techniques,and a meaningful watermark image is ... We propose a robust digital watermarking algorithm for copyright protection.A stable feature is obtained by utilizing QR factorization and discrete cosine transform(DCT) techniques,and a meaningful watermark image is embedded into an image by modifying the stable feature with a quantization index modulation(QIM) method.The combination of QR factorization,DCT,and QIM techniques guarantees the robustness of the algorithm.Furthermore,an embedding location selection method is exploited to select blocks with small modifications as the embedding locations.This can minimize the embedding distortion and greatly improve the imperceptibility of our scheme.Several standard images were tested and the experimental results were compared with those of other published schemes.The results demonstrate that our proposed scheme can achieve not only better imperceptibility,but also stronger robustness against common signal processing operations and lossy compressions,such as filtering,noise addition,scaling,sharpening,rotation,cropping,and JPEG/JPEG2000 compression. 展开更多
关键词 Digital watermarking QR factorization Quantization index modulation (QIM) Discrete cosine transform (DCT)
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部