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971.
972.
根据成缆生产线的工艺要求,提出了一种基于S7-300 PLC和现场总线的3150型盘绞成缆机控制系统的设计方案,给出了3150型盘绞成缆机的整体结构,详细介绍了系统硬件及软件设计,并给出了盘绞头与放线架的同步控制方法。实际应用表明,该系统结构简单、使用灵活方便、控制精度高、人机对话良好,达到了预期目标。 相似文献
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974.
本文通过介绍和分析现代科学技术的发展趋势,结合产品外观设计的基本目的,以及当今数码电子类产品的发展历程,旨在说明现代科技发展与产品外观设计的内在联系和对其潜在的影响,从而更好的指导产品设计。 相似文献
975.
Hsieh-Ching Chen Wei-Chyuan Chen Yung-Ping Liu Chih-Yong Chen Yi-Tsong Pan 《International Journal of Industrial Ergonomics》2009,39(5):708-718
Riders of twelve motorcycles, comprising 6 full-scale motorbikes and 6 motor-scooters, and 5 sedan vehicles, performed test runs on a 20.6 km paved road composed of 5 km, 5 km, and 10.6 km of rural, provincial and urban routes, respectively. Each test run of motorcycle was separately performed under speed limits of 55 km/h and 40 km/h. Tri-axial accelerations of whole-body vibration (WBV) were obtained by using a seat pad and a portable data logger, and the driver's view was videotaped with a portable media recorder. Root mean square (RMS) acceleration, 8-h estimated vibration dose value (VDV(8)) and 8-h estimated daily dose of static compression dose (Sed) were determined from the collected data in accordance with ISO 2631-1 and ISO 2631-5 standards. Experimental results indicate that the WBV values of the sedan vehicle drivers have low RMS, VDV(8) and Sed values (RMS 0.27–0.32 m/s2; VDV(8) 6.3–8.3 m/s1.75; Sed 0.21–0.26 MPa). However, over 90% of the motorcycle riders had VDV(8) (mean 23.5 m/s1.75) exceeding the upper boundary of health guidance caution zone (17 m/s1.75) recommended by ISO 2631-1, or had Sed (mean 1.17 MPa) exceeding the value associated with a high probability of adverse health effects (0.8 MPa) recommended by ISO 2631-5. Over 50% of the motorcycle riders reached these boundary values for VDV and Se in less than 2 h. The WBV exposure levels of the full-scale motorbikes riders and motor-scooter riders were not significantly different. However, the RMS and VDV(8) values of motorcycle riders indicate significant roadway effect (p < 0.001), while their Sed values indicate significant speed limit effect (p < 0.05). This study concludes that the WBV exposure levels of common motorcycle riders are distinctively higher than those of sedans, even on a regular paved road. The impact on health of WBV exposure in motorcycle riders should be carefully addressed with reference to ISO 2631-1 and ISO 2631-5.
Relevance to industry
This study compares the predicted health risks of motorcycle riders according to ISO 2631-1 and ISO 2631-5 standards. Experimental data suggest that the vibration dose value of ISO 2631-1 and daily dose of equivalent static compression stress of ISO 2631-5 have roughly equivalent boundaries for probable health effects. 相似文献976.
We revisit in this paper the concept of decoding binary cyclic codes with Gröbner bases. These ideas were first introduced by Cooper, then Chen, Reed, Helleseth and Truong, and eventually by Orsini and Sala. We discuss here another way of putting the decoding problem into equations: the Newton identities. Although these identities have been extensively used for decoding, the work was done manually, to provide formulas for the coefficients of the locator polynomial. This was achieved by Reed, Chen, Truong and others in a long series of papers, for decoding quadratic residue codes, on a case-by-case basis. It is tempting to automate these computations, using elimination theory and Gröbner bases.Thus, we study in this paper the properties of the system defined by the Newton identities, for decoding binary cyclic codes. This is done in two steps, first we prove some facts about the variety associated with this system, then we prove that the ideal itself contains relevant equations for decoding, which lead to formulas.Then we consider the so-called online Gröbner basis decoding, where the work of computing a Gröbner basis is done for each received word. It is much more efficient for practical purposes than preprocessing and substituting into the formulas. Finally, we conclude with some computational results, for codes of interesting length (about one hundred). 相似文献
977.
This paper presents a novel quadratic optimal neural fuzzy control for synchronization of uncertain chaotic systems via H∞ approach. In the proposed algorithm, a self-constructing neural fuzzy network (SCNFN) is developed with both structure and parameter learning phases, so that the number of fuzzy rules and network parameters can be adaptively determined. Based on the SCNFN, an uncertainty observer is first introduced to watch compound system uncertainties. Subsequently, an optimal NFN-based controller is designed to overcome the effects of unstructured uncertainty and approximation error by integrating the NFN identifier, linear optimal control and H∞ approach as a whole. The adaptive tuning laws of network parameters are derived in the sense of quadratic stability technique and Lyapunov synthesis approach to ensure the network convergence and H∞ synchronization performance. The merits of the proposed control scheme are not only that the conservative estimation of NFN approximation error bound is avoided but also that a suitable-sized neural structure is found to sufficiently approximate the system uncertainties. Simulation results are provided to verify the effectiveness and robustness of the proposed control method. 相似文献
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979.
980.