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城市慢行交通系统是现代城市交通系统的重要组成部分,随着多模式城市交通发展,建立便捷和高效的城市慢行交通网络系统成为现代城市解决交通问题和提升交通运行效率的关键措施。基于此,文中应用统一建模语言(UML)和地理标识语言(GML)建立城市慢行交通网络数据模型,提出一种统一的和一致性的交通地理要素定义和性质描述方法,并阐述基于GML的城市慢行交通网络的地理要素和关系表达。研究成果促进了城市交通地理数据的组织、表达、集成、共享和操作,对建立高效的城市慢行交通网络系统具有重要的理论价值。 相似文献
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Image enhancement technology plays a very important role to improve image quality in image processing. By enhancing some information and restraining other information selectively, it can improve image visual effect. The objective of this work is to implement the image enhancement to gray scale images using different techniques. After the fundamental methods of image enhancement processing are demonstrated, image enhancement algorithms based on space and frequency domains are systematically investigated and compared. The advantage and defect of the above-mentioned algorithms are analyzed. The algorithms of wavelet based image enhancement are also deduced and generalized. Wavelet transform modulus maxima(WTMM) is a method for detecting the fractal dimension of a signal, it is well used for image enhancement. The image techniques are compared by using the mean(μ),standard deviation(?), mean square error(MSE) and PSNR(peak signal to noise ratio). A group of experimental results demonstrate that the image enhancement algorithm based on wavelet transform is effective for image de-noising and enhancement. Wavelet transform modulus maxima method is one of the best methods for image enhancement. 相似文献
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王金成 《计算机光盘软件与应用》2010,(3):15-15
采用HOLTEK生产的AD型单片机HT46R232作为主控制芯片,实时的对大气条件参数温度、湿度、风向和风速进行采集和测定,经过相应的处理后,使用LED显示,并根据气象条件为行人外出提供出行适宜参考指数。同时本系统具有时间显示和设定功能。 相似文献
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Marco Riani 《Computational statistics & data analysis》2010,54(12):3300-3312
The forward search provides data-driven flexible trimming of a Cp statistic for the choice of regression models that reveals the effect of outliers on model selection. An informed robust model choice follows. Even in small samples, the statistic has a null distribution indistinguishable from an F distribution. Limits on acceptable values of the Cp statistic follow. Two examples of widely differing size are discussed. A powerful graphical tool is the generalized candlestick plot, which summarizes the information on all forward searches and on the choice of models. A comparison is made with the use of M-estimation in robust model choice. 相似文献
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Multiband frequency domain synthesis consists in the minimization of a finite family of closed-loop transfer functions on prescribed frequency intervals. This is an algorithmically difficult problem due to its inherent nonsmoothness and nonconvexity. We extend our previous work on nonsmooth H∞ synthesis to develop a nonsmooth optimization technique to compute local solutions to multiband synthesis problems. The proposed method is shown to perform well on illustrative examples. 相似文献
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An NP-hard production–distribution problem for one product over a multi-period horizon is investigated. The aim is to minimize total cost taking production setups, inventory levels and distribution into account. An integer linear model is proposed as a compact problem specification but it cannot be solved to optimality for large instances. Instead of using a classical two-phase approach (production planning and then route construction for each day), metaheuristics that simultaneously tackle production and routing decisions are developed: a GRASP (greedy randomized adaptive search procedure) and two improved versions using either a reactive mechanism or a path-relinking process. These algorithms are evaluated on 90 randomly generated instances with 50, 100 and 200 customers and 20 periods. The results confirm the interest of integrating production and distribution decisions, compared to classical two-phase methods. Moreover, reaction and path-relinking give better results than the GRASP alone. 相似文献