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191.
[Objective ] To meet the requirements of remotely controlling ship in curved, narrow and crowded inland waterways, this paper proposes an approach that consists of CNN-based algorithms and knowledge based models under ship-shore cooperation conditions. [Method]On the basis of analyzing the characteristics of ship-shore cooperation, the proposed approach realizes autonomous perception of the environment with visual simulation at the core and navigation decision-making control based on deep reinforcement learning, and finally constructs an artificial intelligence system composed of image deep learning processing, navigation situation cognition, route steady-state control and other functions. Remote control and short-time autonomous navigation of operating ships are realized under inland waterway conditions, and remote control of container ships and ferries is carried out. [Results]The proposed approach is capable of replacing manual work by remote orders or independent decision-making, as well as realizing independent obstacle avoidance, with a consistent deviation of less than 20 meters. [Conclusions]The developed prototype system carries out the remote control operation demonstration of the above ship types in such waterways as the Changhu Canal Shenzhou line and the Yangtze River, proving that a complete set of algorithms with a CNN and reinforcement learning at the core can independently extract key navigation information, construct obstacle avoidance and control awareness, and lay the foundation for inland river intelligent navigation systems. © 2022 Journal of Clinical Hepatology. All rights reserved. 相似文献
192.
The user interesting degree evaluation index is designed to fulfill the users’ real needs, which includes the user’ attention
degree of commodity, hot commodity and preferential commodity. User interesting degree model (UIDM) is constructed to justify
the value of user interesting degree; the personalization approach is presented; operations of add and delete nodes (branches)
are covered in this paper. The improved e-catalog is more satisfied to users’ needs and wants than the former e-catalog which
stands for enterprises, and the improved one can complete the recommendation of related products of enterprises. 相似文献
193.
Urban arterial performance evaluation has been broadly studied, with the major focus on average travel time estimation. However, in view of the stochastic nature of interrupted flow, the ability to capture the characteristics of travel time variability has become a critical step in determining arterial level of service (LOS). This article first presents a stochastic approach that integrates classic cumulative curves and probability theories in order to investigate delay variability at signalized intersections, as a dominant part of the link travel time variability. This serves as a basis for arterial travel time estimation, which can be obtained through a convolution of individual link travel time distributions. The proposed approach is then applied in the estimation of travel time along one arterial in Shanghai, China, with abundant automatic vehicle identification (AVI) data sources. The travel time variability is evaluated thoroughly at 30-min intervals, with promising results achieved in comparison to the field measurements. In addition, the estimated travel time distributions are utilized to illustrate the probability of multiple LOS ranges, namely, reliability LOS. The results provide insights into how we might achieve a more reliable and informative understanding of arterial performance. 相似文献
194.
It is essential to obtain accurate location of vehicles for new applications of Intelligent Transportation Systems. To remedy the defects of present Global Positioning System and vehicle-to-infrastructure (V-I) positioning technology, a new positioning approach based on vision and V-I communication is proposed. This approach aims at lane-level positioning with lower cost than conventional ones. In this approach, the position of the vehicle is represented by its lateral position (the lane number) and longitudinal position (the distance from entrance of the road) in a course coordinate system along the road; the specific lane the vehicle is occupying (the lane number) can be judged using the information of lane lines detected by vision systems; then the distance to the vehicle is obtained by a Road Side Unit (RSU) during the V-I communication; and the longitudinal position is calculated. The error of the approach on typical operating conditions is analyzed, indicating that the new approach can achieve the accuracy of less than 0.31 m for straight road and 0.58 m for typical arc road with ultra-wideband communication and ranging technologies and rational arrangement of RSUs. The feasibility of this approach is presented. 相似文献
195.
Peng Hang Xinbo Chen Shude Fang Fengmei Luo 《International Journal of Automotive Technology》2017,18(5):785-797
A four-wheel-independent-steering (4WIS) electric vehicle (EV) with steer-by-wire (SBW) system is proposed in this paper. The fast terminal sliding mode controller (FTSMC) is designed for the SBW system to suppress external disturbances. Taking unstructured and structured uncertainties into consideration, a robust controller is designed for the 4WIS EV utilizing μ synthesis approach and the controller order reduction is implemented based on Hankel-Norm approximation. Since sideslip angle is the feedback signal of robust controller and it is hard to measure, the extended Kalman filter (EKF) is employed to estimate sideslip angle. To evaluate the vehicle performance with the designed control system, step and sinusoidal steering maneuvers are simulated and analyzed. Simulation results show that the designed control system have good tracking ability, strong robust stability and good robust performance to improve vehicle stability and handing performance. 相似文献
196.
短线匹配法节段预制拼装技术是将整孔箱梁设计成若干个标准节段,工厂内逐节段匹配预制,架桥机现场拼装的施工技术。该项技术1965年最早出现在法国,在国外得到了广泛应用。2002年自苏通大桥开始,我国逐步实现了短线匹配法的大规模应用以及设计、施工、装备、材料等技术的全面国产化。结合我国已建成的几座代表性的短线匹配法桥梁工程,对短线匹配法节段预制拼装的接缝质量控制、线形控制及长期性能保证等关键要点进行了论述,对短线匹配法施工技术应用中存在的问题及未来发展趋势进行了初步分析。 相似文献
197.
随着预应力技术的发展,体外预应力技术越来越被工程上重视。文章介绍了体外预应力技术的体系,体外预应力技术在桥梁上的应用及其优缺点和体外预应力桥梁的特点,并对体外预应力技术前景进行了展望。 相似文献
198.
目的探讨葡萄胎中Mel-CAM与滋养细胞黏附、浸润之间的关系以及Mel-CAM标记中间型滋养细胞(IT)的增殖情况。方法采用双重免疫组化法,检测Mel-CAM标记IT的Ki-67表达情况。结果葡萄胎中Mel-CAM表达较正常绒毛明显增高,差异有统计学意义(P<0.05);葡萄胎绒毛表面有Mel-CAM标记IT出现,而正常绒毛表面则无;葡萄胎组织中IT的Ki-67指数较正常绒毛明显增高,差异有统计学意义(P<0.05)。结论葡萄胎绒毛表面有Mel-CAM表达,表现出双重分化方向,这可能与葡萄胎的发病机制有关;检测葡萄胎组织中IT的Ki-67指数对于预测葡萄胎的转归有潜在的价值。 相似文献
199.
为开发具有国际竞争力的超大型液化石油气船(VLGC)船型,并为我国船厂获得VLGC的订单提供技术支持,基于CFD数值分析对VLGC进行设计吃水状态的线型优化研究.优化的线型波形平缓,船体表面压力分布均匀,艉部桨盘面伴流分布均匀,模型试验结果与CFD计算结果吻合良好.模型试验结果表明,最终优化设计的线型阻力低,能效高,船舶航速指标先进.对开发的新船型进一步开展不同纵倾压载状态的比较试验研究,结果表明,合理地调整压载纵倾值能有效改善压载状态的阻力性能,降低能耗. 相似文献
200.
从某公司面临的几大问题出发,结合资源共享的分类,对企业完善和健全资源共享机制提出新的实施过程;通过运用新的资源共享机制,提升企业的竞争优势,提高产业链的整体水平,使企业在日益激烈的竞争中脱颖而出. 相似文献