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1.
The deterministic and probabilistic prediction of ship motion is important for safe navigation and stable real-time operational control of ships at sea. However, the volatility and randomness of ship motion, the non-adaptive nature of single predictors and the poor coverage of quantile regression pose serious challenges to uncertainty prediction, making research in this field limited. In this paper, a multi-predictor integration model based on hybrid data preprocessing, reinforcement learning and improved quantile regression neural network (QRNN) is proposed to explore the deterministic and probabilistic prediction of ship pitch motion. To validate the performance of the proposed multi-predictor integrated prediction model, an experimental study is conducted with three sets of actual ship longitudinal motions during sea trials in the South China Sea. The experimental results indicate that the root mean square errors (RMSEs) of the proposed model of deterministic prediction are 0.0254°, 0.0359°, and 0.0188°, respectively. Taking series #2 as an example, the prediction interval coverage probabilities (PICPs) of the proposed model of probability predictions at 90%, 95%, and 99% confidence levels (CLs) are 0.9400, 0.9800, and 1.0000, respectively. This study signifies that the proposed model can provide trusted deterministic predictions and can effectively quantify the uncertainty of ship pitch motion, which has the potential to provide practical support for ship early warning systems. 相似文献
2.
In actual engineering scenarios, limited fault data leads to insufficient model training and over-fitting, which negatively affects the diagnostic performance of intelligent diagnostic models. To solve the problem, this paper proposes a variational information constrained generative adversarial network (VICGAN) for effective machine fault diagnosis. Firstly, by incorporating the encoder into the discriminator to map the deep features, an improved generative adversarial network with stronger data synthesis capability is established. Secondly, to promote the stable training of the model and guarantee better convergence, a variational information constraint technique is utilized, which constrains the input signals and deep features of the discriminator using the information bottleneck method. In addition, a representation matching module is added to impose restrictions on the generator, avoiding the mode collapse problem and boosting the sample diversity. Two rolling bearing datasets are utilized to verify the effectiveness and stability of the presented network, which demonstrates that the presented network has an admirable ability in processing fault diagnosis with few samples, and performs better than state-of-the-art approaches. 相似文献
3.
Bernette Maria Oosterlaken Heiner Friedrich Gijsbertus de With 《Microscopy research and technique》2022,85(1):412-417
Transmission electron microscopy (TEM) is an important analysis technique to visualize (bio)macromolecules and their assemblies, including collagen fibers. Many protocols for TEM sample preparation of collagen involve one or more washing steps to remove excess salts from the dispersion that could hamper analysis when dried on a TEM grid. Such protocols are not standardized and washing times as well as washing solvents vary from procedure to procedure, with each research group typically having their own protocol. Here, we investigate the influence of washing with water, ethanol, but also methanol and 2-propanol, for both mineralized and unmineralized collagen samples via a protocol based on centrifugation. Washing with water maintains the hydrated collagen structure and the characteristic banding pattern can be clearly observed. Conversely, washing with ethanol results in dehydration of the fibrils, often leading to aggregation of the fibers and a less obvious banding pattern, already within 1 min of ethanol exposure. As we show, this process is fully reversible. Similar observations were made for methanol and propanol. Based on these results, a standardized washing protocol for collagenous samples is proposed. 相似文献
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针对采用相关滤波的判别式目标跟踪遇到的瓶颈问题:由于目标快速移动引起边界效应,使得相关滤波器在学习与更新过程中可能会引入错误,最终错误的累积将导致跟踪失败。在采集深度学习特征与样本相似性度量的基础上,提出一种引入交替方向乘子方法的改进相关滤波目标跟踪算法,选择DCNN深度特征有效地表征待跟踪目标的初始状态,通过在线分类过程中样本相似性比对与半监督学习,辅助解决相关滤波器在学习过程中存在的自学习问题。所提目标跟踪算法特别适合训练样本为持续获得的、同时存储空间较小的机器学习过程,提高目标在快速运动与部分遮挡等复杂情况下的跟踪成功率,针对VOT2016标准测试视频的实验表明:当目标面临快速运动时,对比CN、SAMF、STC算法,所提DA-CFT跟踪算法将跟踪成功率分别由60.4%~73.4%、67.2%~82.9%、80.9%~88.1%提升至85.6%~91.0%。 相似文献
6.
Histograms are convenient non-parametric density estimators, which continue to be used ubiquitously. Summary quantities estimated from histogram-based probability density models depend on the choice of the number of bins. We introduce a straightforward data-based method of determining the optimal number of bins in a uniform bin-width histogram. By assigning a multinomial likelihood and a non-informative prior, we derive the posterior probability for the number of bins in a piecewise-constant density model given the data. In addition, we estimate the mean and standard deviations of the resulting bin heights, examine the effects of small sample sizes and digitized data, and demonstrate the application to multi-dimensional histograms. 相似文献
7.
《The Electricity Journal》2020,33(7):106802
The paper aims to investigate the determinants of household electricity consumption in Korea by using both the OLS regression and quantile regression. The results show that the effects of socio-demographic, dwelling, and electricity consumption characteristics on household electricity consumption may differ between two regressions and may differ across quantiles. We found that age group of household head, number of household, housing area, the number of household appliances, and refrigerator usage time were significant in all quantiles. 相似文献
8.
通过对于都县黄麟-祁禄山地区开展1:5万土地质量地球化学调查,在野外土壤样品采集和化验测试的基础上,系统地研究了影响土地质量的各项地球化学指标特征与控制因素,基本查明有益元素、重金属元素分布,划分出重点污染区和绿色土地发展区,并进行土地质量等级评价,为永久基本农田建设、土地资源开发与利用等方面提出建议。 相似文献
9.
《Ceramics International》2020,46(6):7767-7773
Zinc and cadmium based cobalt ferrites ZnxCd0.375-xCo0.625Fe2O4 (where x = 0, 0.075, 0.125, 0.25) were successfully synthesized by a facile co-precipitation technique. Structural, optical and magnetic characteristics of the doped ferrites were systematically analyzed. X-ray Diffraction (XRD) pattern confirmed the formation of cubic spinel structure in all samples. Scanning electron microscopic analysis of surface morphology revealed cubic and spherical shaped ferrite particles. Fourier transform infrared (FTIR) spectroscopy confirmed the existence of metal oxygen (M − O) bonding in the prepared samples. Moreover, the prepared samples exhibited two frequency bands corresponding to phonon vibrational stretching in both octahedral and tetrahedral lattice positions. The optical properties were investigated in detail through photoluminescence (PL) spectroscopy and Raman spectroscopy. The PL spectrum confirmed the strong emission peaks in the ultraviolet to visible region of all the samples. Further, four active Raman modes, associated with cubic spinel structure are identified in all prepared samples. Finally, the magnetic characteristics are evaluated by using vibrating sample magnetometer (VSM) revealing ferrimagnetic and soft magnetic behavior of the samples. As the Zn and Cd co-doping in Co was increased, the Hc was decreased. The magnetic studies show the maximum Hc of 576 Oe for Cd doped cobalt ferrite, and maximum saturation magnetization (Ms) for Zn–Cd doped cobalt ferrite. It is envisaged that the newly prepared Zn–Cd co-doped cobalt ferrite would be appropriate for a number of important applications, for example, magnetic recording devices, sensors, actuators, high-density data storage devices, and biomedical equipments. 相似文献
10.
目的 比较辽宁地区食品来源与临床样本来源沙门氏菌的耐药性,了解不同来源沙门氏菌对14种用抗生素的耐药情况,分析产生差异的原因及其耐药机制。方法 用96孔药敏板,对54份食品来源和55份临床样本来源的沙门氏菌进行14种抗生素的耐药性检测,通过SPSS统计学软件计算,P<0.05说明二者具有显著差异。同时通过PCR方法,对携带耐药基因的整合子目的片段进行扩增,检测两种来源沙门氏菌Ⅰ类整合子携带情况,分析其对多重耐药产生的意义。结果 两种来源沙门氏菌对喹诺酮类抗生素—环丙沙星的耐药率有显著差异(食品耐药率高于临床样本:χ2=13.615,P=0.001<0.05)。两种来源沙门氏菌对β内酰胺类抗生素-头孢噻肟和氨苄西林耐药率有显著差异(临床样本耐药率高于食品样本:头孢噻肟χ2=4.813,P=0.028<0.05;氨苄西林χ2=9.653,P=0.002<0.05,)。二者多重耐药率有显著差异(临床样本多重耐药率高于食品样本:χ2=4.012,P=0.045<0.05)。二者整合子携带率分别为食品样本22.22%临床样本29.09%。结论 耐药性的产生与不同环境压力诱导、自身滥用抗生素的习惯有关,也与Ⅰ类整合子的介导有关,研究结果对环境以及临床抗生素的应用具有指导意义,为进一步探索整合子所携带的耐药基因以及它传递的影响因素提供实验依据。 相似文献