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排序方式: 共有8751条查询结果,搜索用时 31 毫秒
1.
Christian Soize Roger Ghanem 《International journal for numerical methods in engineering》2022,123(1):268-290
The probabilistic learning on manifolds (PLoM) introduced in 2016 has solved difficult supervised problems for the “small data” limit where the number N of points in the training set is small. Many extensions have since been proposed, making it possible to deal with increasingly complex cases. However, the performance limit has been observed and explained for applications for which N is very small and for which the dimension of the diffusion-map basis is close to N. For these cases, we propose a novel extension based on the introduction of a partition in independent random vectors. We take advantage of this development to present improvements of the PLoM such as a simplified algorithm for constructing the diffusion-map basis and a new mathematical result for quantifying the concentration of the probability measure in terms of a probability upper bound. The analysis of the efficiency of this extension is presented through two applications. 相似文献
2.
《全球能源互联网(英文)》2022,5(6):618-626
A novel image sequence-based risk behavior detection method to achieve high-precision risk behavior detection for power maintenance personnel is proposed in this paper. In this method, the original image sequence data is first separated from the foreground and background. Then, the free anchor frame detection method is used in the foreground image to detect the personnel and correct their direction. Finally, human posture nodes are extracted from each frame of the image sequence, which are then used to identify the abnormal behavior of the human. Simulation experiment results demonstrate that the proposed algorithm has significant advantages in terms of the accuracy of human posture node detection and risk behavior identification. 相似文献
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In recent years, the light field (LF) as a new imaging modality has attracted wide interest. The large data volume of LF images poses great challenge to LF image coding, and the LF images captured by different devices show significant differences in angular domain. In this paper we propose a view prediction framework to handle LF image coding with various sampling density. All LF images are represented as view arrays. We first partition the views into reference view (RV) set and intermediate view (IV) set. The RVs are rearranged into a pseudo sequence and directly compressed by a video encoder. Other views are then predicted by the RVs. To exploit the four dimensional signal structure, we propose the linear approximation prior (LAP) to reveal the correlation among LF views and efficiently remove the LF data redundancy. Based on the LAP, a distortion minimization interpolation (DMI) method is used to predict IVs. To robustly handle the LF images with different sampling density, we propose an Iteratively Updating depth image based rendering (IU-DIBR) method to extend our DMI. Some auxiliary views are generated to cover the target region and then the DMI calculates reconstruction coefficients for the IVs. Different view partition patterns are also explored. Extensive experiments on different types LF images also valid the efficiency of the proposed method. 相似文献
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摘要:针对水下无线传感网络中运动节点定位精度低的问题,提出了一种新的基于双层修正无迹卡尔曼的水下节点定位算法(DLMUKF)。该算法利用下层无迹卡尔曼滤波算法对节点状态进行预测,根据各信标节点的测距传播时延对预测的节点状态进行修正。运用上层无迹卡尔曼滤波算法对修正后的状态进行新的预测与修正。仿真实验中,DLMUKF算法的平均定位误差约为传统多边定位算法的15%,约为基于无迹卡尔曼滤波(UKF)定位算法的16%,受节点运动时间与速度的影响最小。通过实验证明DLMUKF算法能更充分利用实际距离值,可以有效减小运动节点的定位误差。 .txt 相似文献
6.
G. C. Morrison H. V. Andersen L. Gunnarsen D. Varol E. Uhde B. Kolarik 《Indoor air》2018,28(1):188-197
Polychlorinated biphenyl (PCB) contamination of buildings continues to pose an exposure threat, even decades after their application in the form of calks and other building materials. In this research, we investigate the ability of clothing to sorb PCBs from contaminated air and thereby influence exposure. The equilibrium concentration of PCB‐28 and PCB‐52 was quantified for nine used clothing fabrics exposed for 56 days to air in a Danish apartment contaminated with PCBs. Fabric materials included pure materials such as cotton and polyester, or blends of polyester, cotton, viscose/rayon, and/or elastane. Air concentrations were fairly stable over the experimental period, with PCB‐28 ranging from 350 to 430 ng/m3 and PCB‐52 ranging from 460 to 550 ng/m3. Mass accumulated in fabric ranged from below detection limits to 4.5 mg/g of fabric. Cotton or materials containing elastane sorbed more than polyester materials on a mass basis. Mass‐normalized partition coefficients above detection limits ranged from 105.7 to 107.0 L/kg. Clothing acts as a reservoir for PCBs that extends dermal exposure, even when outside or in uncontaminated buildings. 相似文献
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现有的时态网络可视化方法大多采用等量时间片来可视化网络的演变,不利于时态模式的快速挖掘和发现。为此,根据时态网络固有的特征提出自适应时间片划分方法(Adaptive Time Slice Partition method,ATSP)。在时态网络的两种表示方式(基于事件的表示方式和基于快照的表示方式)的基础上,构建了ATSP的基础模型,同时提出了一种改进模型用来描述事件间隔时间服从长尾分布的时态网络。为了实现时间片的不等量划分,针对探索任务的不同提出了基于时态模式的ATSP规则和基于中心节点的ATSP规则,并提出了实现算法--层次划分算法(Hierarchical Partition algorithm,HP)和增量划分算法(Incremental Partition algorithm,IP)。实验结果表明,ATSP方法比传统的时间片划分方法更能准确地表示网络的时态特征,且该方法应用于可视化时,能有效归纳并展示网络的特征,明显提高了视觉分析的效率。 相似文献
9.
In this paper, we define a local version of Hudetz correction for the Yager entropy of dynamical systems. It is proved that the introduced function is indeed a local entropy map for the Hudetz correction of the Yager entropy, in the sense that, the Hudetz correction of the Yager entropy of a continuous map on a compact metric space is attained by integrating the introduced local entropy. 相似文献
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