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Combined model based on optimized multi-variable grey model and multiple linear regression 被引量:12
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作者 Pingping Xiong Yaoguo Dang +1 位作者 Xianghua wu Xuemei Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第4期615-620,共6页
The construction method of background value is improved in the original multi-variable grey model (MGM(1,m)) from its source of construction errors. The MGM(1,m) with optimized background value is used to elimin... The construction method of background value is improved in the original multi-variable grey model (MGM(1,m)) from its source of construction errors. The MGM(1,m) with optimized background value is used to eliminate the random fluctuations or errors of the observational data of all variables, and the combined prediction model together with the multiple linear regression is established in order to improve the simulation and prediction accuracy of the combined model. Finally, a combined model of the MGM(1,2) with optimized background value and the binary linear regression is constructed by an example. The results show that the model has good effects for simulation and prediction. 展开更多
关键词 multi-variable grey model (MGM(1 m)) backgroundvalue OPTIMIZATION multiple linear regression combined predic-tion model.
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Non-Probabilistic Reliability Research on Multi-Variable Hydraulic Turbine Blade Model 被引量:1
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作者 庞煜 张翔 +1 位作者 黄洪钟 赖喜德 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第5期584-587,共4页
Based on the interval mathematics and possibility theory, the variables existing in hydraulic turbine blade are described. Considering the multi-failure mode in turbine blade, multi-variable model is established to me... Based on the interval mathematics and possibility theory, the variables existing in hydraulic turbine blade are described. Considering the multi-failure mode in turbine blade, multi-variable model is established to meet the actual situation. Thus, non-probabilistic reliability index is presented by comparing with the output range and the given range. 展开更多
关键词 fuzzy variable interval variable multi-variable model non-probabilistic reliability possibility distribution
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ENHANCING GROUND RESOLUTION OF TM6 BASED ON MULTI-VARIATE REGRESSION MODEL AND SEMI-VARIOGRAM FUNCTION
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作者 MA Hongchao LI Deren 《Geo-Spatial Information Science》 2001年第1期43-49,共7页
It is well known that Landsat TM images are the most widely used remote sensing data in various fields.Usually,it has 7 different electromagnetic spectrum bands,among which the sixth one has much lower ground resoluti... It is well known that Landsat TM images are the most widely used remote sensing data in various fields.Usually,it has 7 different electromagnetic spectrum bands,among which the sixth one has much lower ground resolution compared with the other six bands.Nevertheless,it is useful in the study of rock spectrum reflection,geothermal resources exploration,etc.To improve the ground resolution of TM6 to the level as that of the other six bands is a problem .This paper presents an algorithm based on the combination of multivariate regression model with semivariogram function which can improve the ground resolution of TM6 by "fusing" the data of other six bands.It includes the following main steps: (1) testing the correlation between TM6 and one of TM15,7.If the correlation coefficient between TM6 and another one is greater than a given threshold value,then select the band to the regression analysis as an argument.(2) calculating the size of the template window within which some parameters needed by the regression model will be calculated; (3) replacing the original pixel values of TM6 by those obtained by regression analysis; (4) using image entropy as a measurement to evaluate the quality of the fused image of TM6.The basic mechanism of the algorithm is discussed and the V C ++ program for implementing this algorithm is also presented.A simple application example is given in the last part of this paper,showing the effectiveness of the algorithm. 展开更多
关键词 multi-variate regression model semi-variogram FUNCTION image fusion TEMPLATE WINDOW V C++ PROGRAMMING
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Integration of Lab model and EHOG for human appearance matching across disjoint camera views 被引量:2
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作者 杨彪 林国余 张为公 《Journal of Southeast University(English Edition)》 EI CAS 2012年第4期422-427,共6页
The integration of the Lab model with the extended histogram of oriented gradients (EHOG) is proposed to improve the accuracy of human appearance matching across disjoint camera views under perturbations such as ill... The integration of the Lab model with the extended histogram of oriented gradients (EHOG) is proposed to improve the accuracy of human appearance matching across disjoint camera views under perturbations such as illumination changes and different viewing angles. For the Lab model that describes the global information of observations, a sorted nearest neighbor clustering method is proposed for color clustering and then a partitioned color matching method is used to calculate the color similarity between observations. The Bhattacharya distance is employed for the textural similarity calculation of the EHOG which describes the local information. The global information, which is robust to different viewing angles and scale changes, describes the observations well. Meanwhile, the use of local information, which is robust to illumination changes, can strengthen the discriminative ability of the method. The integration of global and local information improves the accuracy and robustness of the proposed matching approach. Experiments are carried out indoors, and the results show a high matching accuracy of the proposed method. 展开更多
关键词 human appearance matching Lab model extended histogram of oriented gradients (EHOG) disjoint camera views
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基于连续时间随机游走扩散加权成像全容积直方图在乳腺癌诊断中的价值
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作者 章少兰 汪飞 +4 位作者 孙宜楠 张宝媞 陈红 刘孟潇 朱娟 《临床放射学杂志》 北大核心 2026年第1期38-44,共7页
目的探讨基于连续时间随机游走(CTRW)模型扩散加权成像(DWI)全容积直方图参数在乳腺癌诊断中的价值。方法对91例乳腺病变患者进行CTRW模型(D_(m)、α、β参数)和单指数模型(ADC参数)DWI全容积直方图分析。使用独立样本t检验或Mann-Whitn... 目的探讨基于连续时间随机游走(CTRW)模型扩散加权成像(DWI)全容积直方图参数在乳腺癌诊断中的价值。方法对91例乳腺病变患者进行CTRW模型(D_(m)、α、β参数)和单指数模型(ADC参数)DWI全容积直方图分析。使用独立样本t检验或Mann-Whitney U检验比较良性和恶性病变组在D_(m)、α、β及ADC图全容积直方图参数上的差异。此外,采用受试者工作特征曲线分析每个直方图参数在乳腺癌诊断中的效能。结果CTRW-DWI参数图及ADC图全容积直方图参数除D_(m最大值、方差)、α_(90th、最大值、偏度、峰度)、β_(90th、最大值、偏度、峰度)、A_(DC熵、方差、均匀性)外,其他在乳腺良、恶性病变组间差异均有统计学意义(P<0.05)。在各直方图参数组中,D_(m10th)、α_(熵)、β_(熵)、ADC50th的曲线下面积(AUC)最高,分别为0.893、0.855、0.804、0.894。纳入组间差异有统计学意义的CTRW-DWI全容积直方图参数建立综合模型1,AUC为0.972;纳入组间差异有统计学意义的单指数DWI全容积直方图参数建立综合模型2,AUC为0.930。结论基于CTRW-DWI全容积直方图参数在乳腺癌诊断中具有一定价值,多直方图参数联合诊断具有更高的诊断效能。 展开更多
关键词 乳腺癌 连续时间随机游走模型 扩散加权成像 直方图
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An improved mean shift tracking algorithm based on double weighted color histogram
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作者 金永 王振 +1 位作者 王召巴 陈友兴 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第2期171-175,共5页
In practical application,mean shift tracking algorithm is easy to generate tracking drift when the target and the background have similar color distribution.Based on the mean shift algorithm,a kind of background weake... In practical application,mean shift tracking algorithm is easy to generate tracking drift when the target and the background have similar color distribution.Based on the mean shift algorithm,a kind of background weaken weight is proposed in the paper firstly.Combining with the object center weight based on the kernel function,the problem of interference of the similar color background can be solved.And then,a model updating strategy is presented to improve the tracking robustness on the influence of occlusion,illumination,deformation and so on.With the test on the sequence of Tiger,the proposed approach provides better performance than the original mean shift tracking algorithm. 展开更多
关键词 object tracking mean shift color histogram model updating
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Expansion modelling of discrete grey model based on multi-factor information aggregation 被引量:7
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作者 Naiming Xie Chaoyu Zhu Jing Zheng 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第5期833-839,共7页
This paper aims to study a novel expansion discrete grey forecasting model, which could aggregate input information more effectively. In general, existing multi-factor grey forecasting models, such as one order and h ... This paper aims to study a novel expansion discrete grey forecasting model, which could aggregate input information more effectively. In general, existing multi-factor grey forecasting models, such as one order and h variables grey forecasting model (GM (1, h)), always aggregate the main system variable and independent variables in a linear form rather than a nonlinear form, while a nonlinear form could be used in more cases than the linear form. And the nonlinear form could aggregate collinear independent factors, which widely lie in many multi-factor forecasting problems. To overcome this problem, a new approach, named as the Solow residual method, is proposed to aggregate independent factors. And a new expansion model, feedback multi-factor discrete grey forecasting model based on the Solow residual method (abbreviated as FDGM (1, h)), is proposed accordingly. Then the feedback control equation and the parameters' solution of the FDGM (1, h) model are given. Finally, a real application is used to test the modelling accuracy of the FDGM (1, h) model. Results show that the FDGM (1, h) model is much better than the nonhomogeneous discrete grey forecasting model (NDGM) and the GM (1, h) model. 展开更多
关键词 multi-variable system Solow residual method dis crete grey forecasting model grey system theory (GST).
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Complex human activities recognition using interval temporal syntactic model 被引量:1
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作者 夏利民 韩芬 王军 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第10期2578-2586,共9页
A novel method based on interval temporal syntactic model was proposed to recognize human activities in video flow. The method is composed of two parts: feature extract and activities recognition. Trajectory shape des... A novel method based on interval temporal syntactic model was proposed to recognize human activities in video flow. The method is composed of two parts: feature extract and activities recognition. Trajectory shape descriptor, speeded up robust features(SURF) and histograms of optical flow(HOF) were proposed to represent human activities, which provide more exhaustive information to describe human activities on shape, structure and motion. In the process of recognition, a probabilistic latent semantic analysis model(PLSA) was used to recognize sample activities at the first step. Then, an interval temporal syntactic model, which combines the syntactic model with the interval algebra to model the temporal dependencies of activities explicitly, was introduced to recognize the complex activities with a time relationship. Experiments results show the effectiveness of the proposed method in comparison with other state-of-the-art methods on the public databases for the recognition of complex activities. 展开更多
关键词 trajectory shape descriptor speeded up robust features(SURF) histograms of optical flow(HOF) PLSA probabilistic latent semantic analysis syntactic model
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Classifying Machine Learning Features Extracted from Vibration Signal with Logistic Model Tree to Monitor Automobile Tyre Pressure 被引量:1
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作者 P.S.Anoop V.Sugumaran 《Structural Durability & Health Monitoring》 EI 2017年第2期191-208,共18页
Tyre pressure monitoring system(TPMS)is compulsory in most countries like the United States and European Union.The existing systems depend on pressure sensors strapped on the tyre or on wheel speed sensor data.A diffe... Tyre pressure monitoring system(TPMS)is compulsory in most countries like the United States and European Union.The existing systems depend on pressure sensors strapped on the tyre or on wheel speed sensor data.A difference in wheel speed would trigger an alarm based on the algorithm implemented.In this paper,machine learning approach is proposed as a new method to monitor tyre pressure by extracting the vertical vibrations from a wheel hub of a moving vehicle using an accelerometer.The obtained signals will be used to compute through statistical features and histogram features for the feature extraction process.The LMT(Logistic Model Tree)was used as the classifier and attained a classification accuracy of 92.5%with 10-fold cross validation for statistical features and 90.5% with 10-fold cross validation for histogram features.The proposed model can be used for monitoring the automobile tyre pressure successfully. 展开更多
关键词 Machine learning Vibration ACCELEROMETER Statistical Features histogram Features Logistic model tree(LMT) Tyre pressure monitoring system
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State Space Model Predictive Control of an Aerothermic Process with Actuators Constraints
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作者 Mustapha Ramzi Hussein Youlal Mohamed Haloua 《Intelligent Control and Automation》 2012年第1期50-58,共9页
This paper investigates State Space Model Predictive Control (SSMPC) of an aerothermic process. It is a pilot scale heating and ventilation system equipped with a heater grid and a centrifugal blower, fully connected ... This paper investigates State Space Model Predictive Control (SSMPC) of an aerothermic process. It is a pilot scale heating and ventilation system equipped with a heater grid and a centrifugal blower, fully connected through a data acquisition system for real time control. The interaction between the process variables is shown to be challenging for single variable controllers, therefore multi-variable control is worth considering. A multi-variable state space model is obtained from on-line experimental data. The controller design is translated into a Quadratic Programming (QP) problem, in which a cost function subject to actuators linear inequality constraints is minimized. The outcome of the experimental results is that the main control objectives, such as set-point tracking and perturbations rejection under actuators constraints, are well achieved for both controlled variables simultaneously. 展开更多
关键词 multi-variable CONTROL Aerothermic PROCESS Actuators CONSTRAINTS PROCESS Identification STATE Space model PREDICTIVE CONTROL
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基于XGBoost多输出模型实现宫颈癌VMAT中直肠和膀胱的DVH预测 被引量:2
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作者 刘江 梅国建 +1 位作者 尹楚欧 邓娟 《中国医疗设备》 2025年第1期52-56,70,共6页
目的基于XGBoost算法构建多输出模型,预测宫颈癌容积旋转调强放疗中膀胱和直肠的剂量。方法选取于我院进行宫颈癌容积旋转调强放疗的120例患者为研究对象。随机抽取20例患者作为测试集,将剩余100例患者数据按照4∶1采取五折交叉验证方... 目的基于XGBoost算法构建多输出模型,预测宫颈癌容积旋转调强放疗中膀胱和直肠的剂量。方法选取于我院进行宫颈癌容积旋转调强放疗的120例患者为研究对象。随机抽取20例患者作为测试集,将剩余100例患者数据按照4∶1采取五折交叉验证方式构建XGBoost预测模型。将所有患者CT中膀胱和直肠结构的与靶区边界距离直方图信息和计划中的剂量跌落函数f(x)作为输入,提取膀胱和直肠微分剂量体积直方图,并将其以2 Gy为间隔离散为多个剂量端点(Dose Endpoints,DEs)作为输出,建立多输出模型。使用平均绝对误差(Mean Absolute Error,MAE)和均方根误差(Root Mean Square Error,RMSE)评估模型各个DEs预测值与临床实际值之间的差异。使用剂量体积百分比(V_(Rx))对比模型预测积分剂量体积直方图(Cumulative Dose Volume Histogram,cDVH)曲线与临床cDVH的差异。结果直肠剂量体积直方图(Dose Volume Histogram,DVH)曲线中所有DEs的MAE为0.0206,RMSE为0.0287;膀胱DVH曲线中所有DEs的MAE为0.0339,RMSE为0.0450。对比预测值与临床实际值的V_(Rx),约91.8%的膀胱预测值和实际值差异小于5%误差范围。直肠预测值与实际值差异小于5%误差范围占比为94.0%。进一步分析发现,膀胱体积<500 mL时,模型DVH预测表现较好;膀胱体积>500 mL时,模型DVH预测结果有待提高。直肠在各个体积范围内,其模型DVH预测均表现较好。结论基于XGBoost算法的多输出DVH预测模型可帮助临床医师和物理师快速评估直肠和膀胱的器官受量,且该模型无需高性能的图形处理器即可快速完成优化过程,为机器学习在放疗中的应用提供新思路。 展开更多
关键词 宫颈癌 XGBoost 多输出模型 个体化剂量 剂量体积直方图(DVH)预测 剂量跌落系数
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基于分数阶微积分模型DWI全容积直方图分析对乳腺良恶性病变的鉴别诊断价值 被引量:5
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作者 张宝媞 汪飞 +6 位作者 孙宜楠 章少兰 汪敏敏 高何燕 程兰兰 刘孟潇 朱娟 《放射学实践》 北大核心 2025年第3期331-338,共8页
目的:探讨基于分数阶微积分(FROC)模型DWI全容积直方图参数在鉴别乳腺良、恶性病变中的应用价值。方法:回顾性分析本院91例乳腺良恶性病变患者的临床及影像资料。所有患者均行常规MRI平扫、动态增强扫描及多b值DWI扫描,经后处理得到FROC... 目的:探讨基于分数阶微积分(FROC)模型DWI全容积直方图参数在鉴别乳腺良、恶性病变中的应用价值。方法:回顾性分析本院91例乳腺良恶性病变患者的临床及影像资料。所有患者均行常规MRI平扫、动态增强扫描及多b值DWI扫描,经后处理得到FROC-DWI[异常扩散系数(D)、体素内扩散异质性参数(β)和空间参数(μ)]及ADC图全容积直方图参数。采用独立样本t检验或Mann-Whitney U检验比较良恶性病变组的D、β、μ及ADC图全容积直方图参数的差异。通过二元Logistic回归构建综合模型,采用受试者操作特征(ROC)曲线评价综合模型及各直方图参数对乳腺良、恶性病变的诊断效能。结果:除D_(熵)、β_(最大值、峰度、90th、最小值)及ADC_(熵)外,其他FROC-DWI及ADC图全容积直方图参数在乳腺良、恶性病变组间差异均有统计学意义(P<0.05)。在各直方图参数组中,D50th、β_熵、μ偏度、ADC50th的ROC曲线下面积(AUC)最高(分别为0.889、0.813、0.759、0.894)。纳入组间差异有统计学意义的FROC-DWI及ADC图全容积直方图参数建立综合模型1,AUC为0.960;纳入组间差异有统计学意义的FROC-DWI全容积直方图参数建立综合模型2,AUC为0.962。结论:基于FROC-DWI全容积直方图参数在鉴别乳腺良、恶性病变中具有一定价值,在各直方图参数组中,D50th、β_(熵)、μ_(峰度)、ADC_(50th)的诊断价值最高;多直方图参数联合诊断可进一步提高诊断效能。 展开更多
关键词 乳腺肿瘤 分数阶微积分模型 直方图 扩散加权成像 磁共振成像
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基于对比度优化模型的红外图像快速增强算法 被引量:1
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作者 熊湛东 戴声奎 《西北工业大学学报》 北大核心 2025年第1期140-148,共9页
在红外图像对比度增强中,平台直方图均衡是一种效果较好的快速算法,关键在于如何选择合适的平台值。为了解决现有平台直方图算法的缺陷,也为了能同时满足高性能与实时处理的需求,针对三平台直方图算法,提出了一种以对比度为评估参数的... 在红外图像对比度增强中,平台直方图均衡是一种效果较好的快速算法,关键在于如何选择合适的平台值。为了解决现有平台直方图算法的缺陷,也为了能同时满足高性能与实时处理的需求,针对三平台直方图算法,提出了一种以对比度为评估参数的数学优化模型。根据图像特性对第1平台进行自适应预处理,防止过度增强;提出了第1平台与第2平台之间的约束准则,达到图像增强与细节保护之间的平衡;为处在亮区且概率密度为零的灰度级设置第3平台值,以便控制结果图像的动态范围;应用提出的优化模型对3个平台值进行整体约束,通过遍历寻优得到最佳平台值。在多个公开数据库上进行了主观与客观实验,结果表明,与6种现有的平台直方图算法相比,文中所提算法具有相对更好的主观效果与客观指标。对于8 bit图像,文中算法的处理时间约为0.02 s,具有较高的实时性。 展开更多
关键词 自适应平台直方图 数学优化模型 平台约束准则 对比度增强 红外图像
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基于混合自然梯度与轻量梯度增加的电力工程成本预测方法 被引量:1
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作者 宋坤 石晶 +2 位作者 郑瑛楠 张如玉 刘伯楠 《沈阳工业大学学报》 北大核心 2025年第2期183-189,共7页
【目的】电力工程建设成本的准确预测对资源配置和决策优化至关重要。传统成本估算方法依赖于人工经验,容易受到工程项目复杂性和不确定性的影响,导致预测误差较大。近期广受关注的机器学习技术则为电力工程成本的预测提供了新的解决方... 【目的】电力工程建设成本的准确预测对资源配置和决策优化至关重要。传统成本估算方法依赖于人工经验,容易受到工程项目复杂性和不确定性的影响,导致预测误差较大。近期广受关注的机器学习技术则为电力工程成本的预测提供了新的解决方案。但现有模型往往缺乏对预测结果不确定性的评估,且存在预测精度低、训练效率低、容易过拟合的缺点。本文提出了一种基于混合自然梯度与轻量梯度增加模型的电力工程成本预测方法,旨在提高预测精度,同时提供预测结果的不确定性估计。【方法】自然梯度增加模型能够估计预测值概率分布的特点,可应用于电力工程成本预测领域。然而,考虑到自然梯度增加模型在训练效率和过拟合问题中的不足,借鉴了轻量梯度增加模型的直方图优化算法,并将其融合到自然梯度增加模型中,形成了一种基于混合自然梯度与轻量梯度增加模型的电力工程成本预测方法,该模型不仅能够提高预测精度,还能够量化分析预测结果的不确定性。【结果】为验证所提模型的有效性,选用2002—2022年间发布的全真工程造价BIM数据库进行分析,该数据库包含2000条电力工程数据。提出的混合模型在测试集上表现优异,相关系数、均方根误差和平均偏置误差等指标均优于其他模型,且测试集上预测结果处于置信度为95%预测区间的概率达到了94.3%。相较于自然梯度增加模型,混合模型不仅提高了预测精度,还有效避免了过拟合问题,并在训练效率方面表现较好。【结论】本文提出的混合自然梯度与轻量梯度增加模型能够在提高预测精度的同时进行预测结果的不确定性估计,满足电力工程成本预测的多样化需求。实验验证了该模型在预测精度、泛化能力和训练效率上的优势,特别适用于复杂电力工程项目的成本估算。研究的创新之处在于提出了一种新型混合模型,结合了轻量梯度增加模型训练效率高以及自然梯度增加模型可提供预测结果的不确定性估计的双重优势,解决了传统模型训练效率低、容易过拟合的问题,并且可以量化分析预测结果的不确定性,能够为优化资源配置与提高决策效率提供有力支持。 展开更多
关键词 电力工程 成本预测 自然梯度增加模型 轻量梯度增加模型 混合模型 直方图优化算法 预测结果 不确定性
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基于剂量表面积直方图的前列腺癌放疗致放射性直肠炎Nomogram预测模型研究
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作者 葛旭东 崔书君 田龙 《肿瘤学杂志》 2025年第3期238-243,共6页
[目的]基于新型放疗计划工具评价结果等临床资料创建前列腺癌放疗致急性放射性直肠炎(radiation proctitis,RP)Nomogram预测模型,评价模型的临床应用价值。[方法]筛选河北北方学院附属第一医院2020年7月至2024年7月前列腺癌患者200例,... [目的]基于新型放疗计划工具评价结果等临床资料创建前列腺癌放疗致急性放射性直肠炎(radiation proctitis,RP)Nomogram预测模型,评价模型的临床应用价值。[方法]筛选河北北方学院附属第一医院2020年7月至2024年7月前列腺癌患者200例,采用中央随机系统分配法分为建模组(n=140)和验证组(n=60)。基于患者CT影像资料创建剂量表面积直方图(dose and surface histogram,DSH)。基于建模组DSH评价结果等临床资料,采用Logistic回归分析急性RP影响因素,并创建Nomogram预测模型。通过建模组内部验证和验证组外部验证评价模型的临床应用价值。[结果]Nomogram预测模型显示肿瘤体积(OR=1.420,95%CI:1.105~2.394)、计划肿瘤体积最大剂量(OR=2.171,95%CI:1.374~3.763)、S_(70)(OR=2.956,95%CI:1.579~5.093)、S_(78)(OR=4.735,95%CI:1.983~8.227)均是影响急性RP发生的独立危险因素(P均<0.05)。肿瘤体积、计划肿瘤体积最大剂量、S_(70)、S_(78)预测急性RP的曲线下面积(area under curve,AUC)分别为0.610(95%CI:0.572~0.733)、0.658(95%CI:0.584~0.765)、0.692(95%CI:0.603~0.793)和0.703(95%CI:0.623~0.835)。建模组内部验证:模型一致性指数为0.832(95%CI:0.781~0.949),校准曲线上观测值与实际值一致性良好,模型能够提供高于各独立危险因素的临床净收益。建模组和验证组外部验证:模型预测两组急性RP的AUC均高于各独立危险因素,两组ROC曲线拟合良好(χ^(2)=1.893,P>0.05)。[结论]基于DSH评价结果等临床资料的急性RP Nomogram预测模型具有一定的临床应用价值,能够为急性RP防治提供有价值的参考依据。 展开更多
关键词 前列腺肿瘤 剂量表面积直方图 放射性直肠炎 Nomogram模型 预测
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融合暗通道复原和分段均衡的红外图像增强
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作者 袁珂 《红外技术》 北大核心 2025年第9期1167-1173,共7页
空气中悬浮粒子与雾气对红外光的反射和散射,会导致红外成像的对比度和清晰度较低,本文提出了融合暗通道复原和分段均衡的红外图像增强方法。根据大气散射模型,将红外图像分割为非高亮区域和高亮区域,用暗通道先验估计非高亮区域的透射... 空气中悬浮粒子与雾气对红外光的反射和散射,会导致红外成像的对比度和清晰度较低,本文提出了融合暗通道复原和分段均衡的红外图像增强方法。根据大气散射模型,将红外图像分割为非高亮区域和高亮区域,用暗通道先验估计非高亮区域的透射率,而用带参的暗通道先验估计高亮区域的透射率,用高斯滤波图像的最大像素值对大气光值进行估计,从而对红外图像进行复原。将暗通道先验复原的红外图像的灰度级分为直方图频次均等的三部分,然后分别将它们在对应等分的3个灰度级子空间上进行直方图均衡。实验结果显示,相对于文献[6]、[8]、[10]和[13]的方法,提出方法能在更大程度上改善红外图像的视觉效果,增强图像的平均梯度、信息熵和变异系数分别高于现有方法11.8%、1.38%和8.13%以上。因此,提出方法具有更好的红外图像增强效果。 展开更多
关键词 红外图像增强 大气散射模型 暗通道先验 透射率 分段直方图均衡
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基于MVH的气动调节阀气室漏气在线故障诊断
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作者 丁栋杰 尚群立 《高技术通讯》 北大核心 2025年第1期85-92,共8页
气室漏气是气动调节阀常见故障之一,虽然已有许多故障诊断方法,但大多是基于操作条件不变的稳态情况下进行的。然而,在实际应用中操作条件随着工况需求而改变,而这些方法无法满足在线故障诊断的需要。本文提出了基于多变量直方图(multiv... 气室漏气是气动调节阀常见故障之一,虽然已有许多故障诊断方法,但大多是基于操作条件不变的稳态情况下进行的。然而,在实际应用中操作条件随着工况需求而改变,而这些方法无法满足在线故障诊断的需要。本文提出了基于多变量直方图(multivariable histogram,MVH)的气动调节阀气室漏气在线故障诊断方法,将阀位设定值作为解释变量,气室气压作为观察变量,建立MVH参考模型和实时模型,模型的输出为解释变量所对应观察变量的分布,此时故障可以看作观察变量分布的变化,通过比较参考模型和实时模型输出分布差异的阈值,对气室漏气故障及其严重程度进行实时诊断。Simulink仿真平台数据和实验台架真实数据都验证了该方法的有效性。 展开更多
关键词 气动调节阀 气室漏气 在线故障诊断 多变量直方图模型
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Urban landscape classification using Chinese advanced high-resolution satellite imagery and an object-oriented multi-variable model 被引量:1
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作者 Li-gang MA Jin-song DENG +2 位作者 Huai YANG Yang HONG Ke WANG 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2015年第3期238-248,共11页
The Chinese ZY-1 02C satellite is one of the most advanced high-resolution earth observation systems designed for terrestrial resource monitoring. Its capability for comprehensive landscape classification, especially ... The Chinese ZY-1 02C satellite is one of the most advanced high-resolution earth observation systems designed for terrestrial resource monitoring. Its capability for comprehensive landscape classification, especially in urban areas, has been under constant study. In view of the limited spectral resolution of the ZY-1 02C satellite (three bands), and the complexity and hetero- geneity across urban environments, we attempt to test its performance of urban landscape classification by combining a multi- variable model with an object-oriented approach. The multiple variables including spectral reflection, texture, spatial autocorre- lation, impervious surface fraction, vegetation, and geometry indexes were first calculated and selected using forward stepwise linear discriminant analysis and applied in the following object-oriented classification process. Comprehensive accuracy as- sessment which adopts traditional error matrices with stratified random samples and polygon area consistency (PAC) indexes was then conducted to examine the real area agreement between a classified polygon and its references. Results indicated an overall classification accuracy of 92.63% and a kappa statistic of 0.9124. Furthermore, the proposed PAC index showed that more than 82% of all polygons were correctly classified. Misclassification occurred mostly between residential area and barren/farmland. The presented method and the Chinese ZY-1 02C satellite imagery are robust and effective for urban landscape classification. 展开更多
关键词 ZY-1 02C satellite CLASSIFICATION URBAN multi-variable model
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月球遥感影像空间基准统一研究:以嫦娥一号DOM影像为例
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作者 严瑶 鲁洋 +2 位作者 李清 王翔 陈建平 《北京测绘》 2025年第5期626-630,共5页
针对月球探测器在获取月球表面遥感数据时因轨道器自身及外界因素导致的几何不一致性问题,本文采用相位一致性方向直方图多模态影像匹配方法和有理多项式纠正模型,对嫦娥一号数字正射影像(DOM)中的嫦娥三号和嫦娥四号着陆区进行了空间... 针对月球探测器在获取月球表面遥感数据时因轨道器自身及外界因素导致的几何不一致性问题,本文采用相位一致性方向直方图多模态影像匹配方法和有理多项式纠正模型,对嫦娥一号数字正射影像(DOM)中的嫦娥三号和嫦娥四号着陆区进行了空间基准统一研究。研究结果表明,该方法在对嫦娥一号影像(非高纬度地区)进行配准时具有较高的精度。定性和定量的分析结果显示,本文提出的方法能够有效地改善影像间的几何不一致性,提高了影像配准的准确性,从而促进了对月球数据的比较研究和协同利用,为后续月球数据的深入研究提供了可靠的基础。 展开更多
关键词 嫦娥一号数字正射影像(DOM) 空间基准统一 相位一致性方向直方图 有理多项式模型
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基于CT灰度直方图构建小于20 mm肺磨玻璃结节浸润性的诊断预测模型
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作者 陈海民 陈小华 顾菱香 《临床放射学杂志》 北大核心 2025年第7期1244-1248,共5页
目的基于CT灰度直方图相关参数构建小于20 mm肺磨玻璃结节(GGN)患者浸润性的诊断预测模型。方法前瞻性选取2020年1月至2024年6月收治的结节直径<20 mm的GGN患者共200例,搜集患者一般资料、临床资料和CT检查影像学资料。根据病理检查... 目的基于CT灰度直方图相关参数构建小于20 mm肺磨玻璃结节(GGN)患者浸润性的诊断预测模型。方法前瞻性选取2020年1月至2024年6月收治的结节直径<20 mm的GGN患者共200例,搜集患者一般资料、临床资料和CT检查影像学资料。根据病理检查结果将患者分为浸润性低风险组(n=82)和高风险组(n=118),并根据患者资料以单因素分析和Logistic回归分析构建浸润性诊断预测模型。结果单因素分析结果显示结节最长径和CT灰度直方图的均值、方差、10%分位数、50%分位数、90%分位数、99%分位数有统计学差异(P均<0.05),进一步Logistic回归分析将结节最长径和CT灰度直方图的均值、方差、10%分位数、50%分位数、90%分位数、99%分位数纳入模型方程构建,构建的模型方程为Logit P=-27.686+0.044×(均值)+0.003×(方差)+0.040×(10%分位数)+0.029×(50%分位数)+0.031×(90%分位数)+0.035×(99%分位数)+0.027×(结节最大径),模型的受试者工作特征曲线(ROC)曲线下面积(AUC)为0.970(95%CI:0.947~0.992),敏感度为0.949,特异度为0.915,预测诊断准确率为93.50%(187/200),Hosmer-Lemeshow拟合优度检验显示,χ^(2)=13.147,P=0.107。结论本研究基于CT灰度直方图参数构建的诊断预测模型具有较高的预测价值,能够帮助临床诊断筛查小于20 mm GGN高风险浸润性的患者,值得临床推广应用。 展开更多
关键词 CT灰度直方图 肺磨玻璃结节 浸润性肺腺癌 诊断模型
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