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71.
利用数学极值理论分析了管道无压流最大过流量、最大流速的发生工况,并建立了最大过流量、最大流速与管线纵坡、管径、管道糙率的关系表达式,为管道设计提供参考和依据。 相似文献
72.
Davide Cacciarelli;Murat Kulahci;John Sølve Tyssedal; 《Quality and Reliability Engineering International》2024,40(1):277-296
In many industrial applications, obtaining labeled observations is not straightforward as it often requires the intervention of human experts or the use of expensive testing equipment. In these circumstances, active learning can be highly beneficial in suggesting the most informative data points to be used when fitting a model. Reducing the number of observations needed for model development alleviates both the computational burden required for training and the operational expenses related to labeling. Online active learning, in particular, is useful in high-volume production processes where the decision about the acquisition of the label for a data point needs to be taken within an extremely short time frame. However, despite the recent efforts to develop online active learning strategies, the behavior of these methods in the presence of outliers has not been thoroughly examined. In this work, we investigate the performance of online active linear regression in contaminated data streams. Our study shows that the currently available query strategies are prone to sample outliers, whose inclusion in the training set eventually degrades the predictive performance of the models. To address this issue, we propose a solution that bounds the search area of a conditional D-optimal algorithm and uses a robust estimator. Our approach strikes a balance between exploring unseen regions of the input space and protecting against outliers. Through numerical simulations, we show that the proposed method is effective in improving the performance of online active learning in the presence of outliers, thus expanding the potential applications of this powerful tool. 相似文献
73.
Yue Li Jikai Lu Dashan Shang Qi Liu Shuyu Wu Zuheng Wu Xumeng Zhang Jianguo Yang Zhongrui Wang Hangbing Lv Ming Liu 《Advanced materials (Deerfield Beach, Fla.)》2020,32(47):2003018
Spiking neural networks (SNNs) sharing large similarity with biological nervous systems are promising to process spatiotemporal information and can provide highly time- and energy-efficient computational paradigms for the Internet-of-Things and edge computing. Nonvolatile electrolyte-gated transistors (EGTs) provide prominent analog switching performance, the most critical feature of synaptic element, and have been recently demonstrated as a promising synaptic device. However, high performance, large-scale EGT arrays, and EGT application for spatiotemporal information processing in an SNN are yet to be demonstrated. Here, an oxide-based EGT employing amorphous Nb2O5 and LixSiO2 is introduced as the channel and electrolyte gate materials, respectively, and integrated into a 32 × 32 EGT array. The engineered EGTs show a quasi-linear update, good endurance (106) and retention, a high switching speed of 100 ns, ultralow readout conductance ( < 100 nS), and ultralow areal switching energy density (20 fJ µ m−2). The prominent analog switching performance is leveraged for hardware implementation of an SNN with the capability of spatiotemporal information processing, where spike sequences with different timings are able to be efficiently learned and recognized by the EGT array. Finally, this EGT-based spatiotemporal information processing is deployed to detect moving orientation in a tactile sensing system. These results provide an insight into oxide-based EGT devices for energy-efficient neuromorphic computing to support edge application. 相似文献
74.
《International Journal of Hydrogen Energy》2020,45(46):25426-25437
The fuel mixing process within the combustion chamber is a critical procedure for advance of scramjet engine. In current study, the influence of free stream angle on the fuel mixing process of multi jets was thoroughly investigated. This research attempts to applied computational technique to disclose the structure of multi-fuel jets when the supersonic air stream is not normal to the jet direction. The effect of both positive and negative supersonic free stream on the diffusion and penetration of multi-hydrogen jets is fully described. The attention of this research is the flow structure of the multi jets and their interaction in the presence of different free stream angle. Our results indicate that the positive free stream angle expands the mixing zone in the downstream while the negative angle of free stream limited jet distribution inside the combustor. Our results show that mixing efficiency increase approximately 50% when the angle of free stream augments from +20° to −20°. According to our findings, mixing efficiency surges up to 17% when the jet spaces are increased from 4Dj to 10 Dj. 相似文献
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This paper presents both a calculus for stream processing, named Brooklet, and its realization as an intermediate language, named River. Because River is based on Brooklet, it has a formal semantics that enables reasoning about the correctness of source translations and optimizations. River builds on Brooklet by addressing the real‐world details that the calculus elides. We evaluated our system by implementing front‐ends for three streaming languages, and three important optimizations, and a back‐end for the System S distributed streaming runtime. Overall, we significantly lower the barrier to entry for new stream‐processing languages and thus grow the ecosystem of this crucial style of programming. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
80.
The Semantic Web technologies are being increasingly used for exploiting relations between data. In addition, new tendencies of real-time systems, such as social networks, sensors, cameras or weather information, are continuously generating data. This implies that data and links between them are becoming extremely vast. Such huge quantity of data needs to be analyzed, processed, as well as stored if necessary. In this position paper, we will introduce recent work on Real-Time Business Intelligence combined with semantic data stream management. We will present underlying approaches such as continuous queries, data summarization and matching, and stream reasoning. 相似文献