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11.
介绍了抽动式衬套正挤切边工艺、模具结构及设计要点 ,该模具结构简单合理 ,能在1台压机上依次完成挤压成形和切边两道工序 ,效率较高 相似文献
12.
文章以一三平动自由度并联机构为研究对象,有效解决了因理论模型控制实际机构引起的空间层面不对称的问题,进而提高了系统的控制精度。首先建立了坐标系和分析误差源,在此基础上借助空间矢量链分析方法,推导了含误差参数机构控制的正、逆解模型,有效地解决了因立柱导轨垂直度误差引起的机构误差问题。仿真结果验证了模型的正确性,研究成果已应用此类机构的开发中。 相似文献
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A Maximum Principle via Malliavin calculus for combined stochastic control and impulse control of forward‐backward systems 下载免费PDF全文
We consider a combined stochastic control and impulse control problem of forward‐backward systems driven by Lévy processes, where both the system coefficients and the objective performance functional are allowed to be random, non‐Markovian; the information available to the controller is partial information. Applying a Malliavin calculus approach, we derive a maximum principle for this control problem, where the adjoint processes are explicitly represented by the parameters and the states of the system. Finally, we give two examples of applications. © 2015 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd 相似文献
15.
The forward scattering of light in a conventional inverted optical microscope by nanoparticles ranging in diameter from 10 to 50nm has been used to automatically and quantitatively identify and track their location in three-dimensions with a temporal resolution of 200ms. The standard deviation of the location of nominally stationary 50-nm-diameter nanoparticles was found to be about 50nm along the light path and about 5nm in the plane perpendicular to the light path. The method is based on oscillating the microscope objective along the light path using a piezo actuator and acquiring images with the condenser aperture closed to a minimum to enhance the effects of diffraction. Data processing in the time and spatial domains allowed the location of particles to be obtained automatically so that the technique has potential applications both in the processing of nanoparticles and in their use in a variety of fields including nanobiotechnology, pharmaceuticals and food processing where a simple optical microscope maybe preferred for a variety of reasons. 相似文献
16.
Testing Forecast Accuracy of Foreign Exchange Rates: Predictions from Feed Forward and Various Recurrent Neural Network Architectures 总被引:3,自引:1,他引:2
In this research, we work with data of futures contracts on foreign exchange rates for British pound (BP), Canadian dollar
(CD), and Japanese yen (JY) that are traded at the Chicago Mercantile Exchange (CME) against US dollars. We model relationships
between exchange rates in these currencies using linear models, feed forward artificial neural networks (ANN), and three versions
of recurrent neural networks (RNN1, RNN2 and RNN3) for predicting exchange rates in these currencies against the US dollar.
Our results on forecast evaluations based on AGS test the tests of forecast equivalence between any two competing models among
the entire models employed for each of the series show that ANN and the three versions of RNN models offer superior forecasts
for predicting BP, CD and JY exchange rates although the forecast evaluations based on MGN test are in sharp contrast. On
the other hand forecast based on SIGN test shows that ANN and all the versions of RNN models offer superior forecasts for
BP and CD in exception of JY exchange rates. The results for forecast evaluation for all the models for each of the series
based on summary measures of forecast evaluations show that RNN3 model appears to offer the most accurate predictions of BP
and RNN1 for JP exchange rates. However, none of the RNN models appear to be statistically superior to the benchmark (i.e.,
linear model) for predicting CD exchange rates.
相似文献
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Perfect forward secure identity-based authenticated key agreement protocol in the escrow mode 总被引:1,自引:0,他引:1
CHOO Kim-Kwang Raymond 《中国科学F辑(英文版)》2009,52(8):1358-1370
The majority of existing escrowable identity-based key agreement protocols only provide partial forward secrecy. Such protocols are, arguably, not suitable for many real-word applications, as the latter tends to require a stronger sense of forward secrecy—perfect forward secrecy. In this paper, we propose an efficient perfect forward-secure identity-based key agreement protocol in the escrow mode. We prove the security of our protocol in the random oracle model, assuming the intractability of the Gap Biline... 相似文献
19.
Internet视频业务的普及和用户越来越高的服务需求推动了实时流媒体业务的迅速发展,流媒体业务的服务质量(QoS)成为业界研究的热点.由于网络的复杂性,流媒体的实时调度控制算法是解决流媒体QoS的关键.结合FEC编码技术和Kalman数字滤波技术,提出一种基于QoS的改进FEC调度传输控制算法——QFEC.该算法根据接收方的状态合理调度流媒体业务,并结合Kalman滤波器原理完成传输速率控制.通过算法状态分析,以及实验数据和性能分析表明,该调度算法能够维持视频数据良好的连续传输,降低视频流的丢包率,显著改善流媒体业务的QoS. 相似文献
20.
Sebastian Ronneberger Junfang Zhang Yuxin Liu Felix F. Loeffler 《Advanced functional materials》2023,33(17):2210116
Tagging, tracking, or validation of products are often facilitated by inkjet-printed optical information labels. However, this requires thorough substrate pretreatment, ink optimization, and often lacks in printing precision/resolution. Herein, a printing method based on laser-driven deposition of solid polymer ink that allows for printing on various substrates without pretreatment is demonstrated. Since the deposition process has a precision of <1 µm, it can introduce the concept of sub-positions with overlapping spots. This enables high-resolution fluorescent labels with comparable spot-to-spot distance of down to 15 µm (444,444 spots cm−2) and rapid machine learning-supported readout based on low-resolution fluorescence imaging. Furthermore, the defined thickness of the printed polymer ink spots can be used to fabricate multi-channel information labels. Additional information can be stored in different fluorescence channels or in a hidden topography channel of the label that is independent of the fluorescence. 相似文献