全文获取类型
收费全文 | 156篇 |
免费 | 4篇 |
专业分类
公路运输 | 35篇 |
综合类 | 44篇 |
水路运输 | 40篇 |
铁路运输 | 30篇 |
综合运输 | 11篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 15篇 |
2013年 | 14篇 |
2012年 | 15篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 14篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1998年 | 2篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1988年 | 1篇 |
排序方式: 共有160条查询结果,搜索用时 187 毫秒
91.
92.
93.
94.
Monocular visual servo-based stabilization control of underactuated unmanned surface vehicle北大核心CSCD
[Objectives ] Aiming at the accurate posture stabilization problem of an under-actuated unmanned surface vehicle (USV) in GPS-denied environments, a monocular visual servo stabilization control scheme is proposed based on homography.[Methods]By virtue of the homography decomposition technique, posture errors with an unknown scale factor are directly reconstructed from current and desired images, which thoroughly removes the calibration of extrinsic camera parameters and priori information on visual targets; with respect to the under-actuation constraint, a periodic function to persistently excite the yaw angle is incorporated into the continuous time-variant output feedback controller, allowing the USV to be stabilized in the absence of image depth, movement velocities and model parameters.[Results]Under the framework of the Lyapunov theory, the closed-loop visual servo system of the USV is rigorously proven to be asymptotically stable by Barbalat lemma.[Conclusions]By installing an onboard monocular camera, USV posture errors can be precisely stabilized with the aid of the proposed visual servo strategy, providing significant technique support for practical applications including docking, berthing, dynamic positioning, etc. © 2022 Journal of Clinical Hepatology. All rights reserved. 相似文献
95.
通过研究论述开放国民经济市场体系与宏观产出问题,建立了一个宏观产出的最 大化优化模型.并通过对这一数学模型分析最后探讨对其求解的各种可行的有效方法. 相似文献
96.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(3):471-493
This paper presents the application of a nominal control design algorithm for rollover prevention of heavy articulated vehicles with active anti-roll-bar control. This proposed methodology is based on an extension of linear quadratic regulator control for ‘state derivative-induced (control coupled) output regulation’ problems. For heavy articulated vehicles with multiple axles, a performance index with multiple rollover indices is proposed. The proposed methodology allows us to compare the usefulness of various control configurations (i.e. actuators at different axles of the vehicle) based on the interaction of this control configuration with vehicle dynamics. Application of this methodology to a specific heavy articulated vehicle with a tractor semi-trailer shows that a single active anti-roll-bar system at the trailer unit gives better performance than multiple-axle actuators at tractor and trailer together with the single lane change manoeuvre as the external disturbance. Thus, the proposed methodology of this paper not only highlights the importance of the interactions between control and vehicle dynamics in rollover prevention problems but, in fact, proposes a novel technique to exploit the benefits of these interactions judiciously. 相似文献
97.
为了提高对水中目标的识别能力,研究使用DS证据理论对多分类器进行融合,论述以往确定BPA方法的优缺点,并在此基础上提出一种新的利用分类器性能和输出信任度来确定BPA的多分类器融合方法,实验证明这种方法在对水中目标进行识别问题中的优越性,为进一步研究分类器融合在目标识别中的应用提供参考. 相似文献
98.
99.
本文利用灰色理论中的GM(1,1)预测模型对某工业城市生活垃圾产生量进行预测。根据垃圾量的发展趋势,提出在分类收集的基础上采取综合利用、焚烧和卫生填埋的处理方法,并对综合处理方法中的管理与技术问题作了探讨。 相似文献
100.
Khac Duc Do 《船舶与海洋工程学报》2011,10(3):325-332
A constructive method was presented to design a global robust and adaptive output feedback controller for dynamic positioning of surface ships under environmental disturbances induced by waves, wind, and ocean currents. The ship’s parameters were not required to be known. An adaptive observer was first designed to estimate the ship’s velocities and parameters. The ship position measurements were also passed through the adaptive observer to reduce high frequency measurement noise from entering the control system. Using these estimate signals, the control was then designed based on Lyapunov’s direct method to force the ship’s position and orientation to globally asymptotically converge to desired values. Simulation results illustrate the effectiveness of the proposed control system. In conclusion, the paper presented a new method to design an effective control system for dynamic positioning of surface ships. 相似文献