排序方式: 共有34条查询结果,搜索用时 15 毫秒
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鉴于广义预测控制(GPC)方法能用同一方式处理设备和安全约束,且具有较强的抗扰动能力,提出了一种基于GPC的船舶动力定位约束控制器设计方法。运用前馈控制器克服风力扰动的影响,且所产生的前馈量被用来实时修正推力约束,在修正后的推力约束下滚动优化GPC。对承受风、浪、流扰动的某供应船,采用提出的方法设计控制器,并进行仿真验证。仿真结果表明,所设计的控制器抗扰动能力较强,能完成对船舶的动力定位约束控制。 相似文献
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Since Tian Jun proposed the difference expansion embedding technique, based on which, many reversible watermarking techniques
were proposed. However, these methods do not perform well when the payload is high. In this paper, we proposed an expandable
difference threshold controlled scheme for these three methods. Experiments show that our scheme improves the performance
of these three methods for heavy payload. 相似文献
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Computer-aided detection (CAD) for CT colonography refers to a scheme that automatically detects polyps in CT images of colon. Current CAD schemes already have a relatively high sensitivity and a low false positive rate. However, misdiagnosis and missed diagnosis are still common to happen, mainly due to the existence of haustral folds (HFs). An innovative idea of segmenting semilunar HFs from the smooth colonic wall and then using different methods to detect polyps on HFs and those on the smooth colonic wall is proposed in this paper to reduce the false positives and false negatives caused by HFs. For the polyps on HFs, a novel segmentation method is specially developed based on complementary geodesic distance transformation (CGDT). The proposed method is tested on four different models and real CT data, The property of CGDT is proved and our method turns out to be effective for HF segmentation and polyp segmentation. The encouraging experimental results primarily show the feasibility of the proposed method and its potential to improve the detection performance of CAD schemes. 相似文献
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为了精准设计水面船舶动力定位控制系统,将无迹卡尔曼布西滤波与非切换解析模型预测控制方法相结合提出一种预测控制器的设计方法.采用无迹卡尔曼布西滤波算法解决非线性连续系统的滤波问题,获取船舶运动状态的估计值;结合相对阶概念,根据船舶运动非线性模型,应用非切换解析模型预测控制方法设计动力定位非线性控制器,使船舶保持在指定位置.研究结果表明:设计控制器的输出较为平滑,有利于减少推进器磨损;设计控制器使船舶北向位置调节时间小于40 s,超调量小于5%,东向位置调节时间小于60 s,超调量小于5%,艏向角度的最大偏移量小于1.5°,令船舶快速到达了指定位置. 相似文献
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<正>古城交通发展策略是用以指导、约束和协调古城交通行为的总则,也是实现合理交通模式、支撑古城保护与发展战略目标实现的保障机制和主要抓手。针对我国古城保护与交通发展面临的主要问题,经综合分析研究,本文提出关于我国古城交通发展策略的几点想法。 相似文献
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