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981.
Abstract

A numerical technique for integrating the full Navier‐Stokes and diffusion equations through an initial value problem has been used to investigate the time development of a line buoyant source issuing in a density‐stratified environment. The basic physical features and some structures of the interactions of the motion at the intermediate mixing region are obtained. Results show that the stratification tends to inhibit the flow development of the buoyant source and to encourage the formation of a recirculatory vortex on the lower region near the source and the upper region.  相似文献   
982.
Many methods for multinational License Plate Detection (LPD) have been proposed in recent times but most of them are not sophisticated enough to handle complex backgrounds. Moreover, their ability to handle various environmental and illumination conditions has been limited and still needs improvement. In this paper, we propose a novel technique to detect license plates of vehicles regardless of their color, size, and content. As the rear vehicle lights are an essential part of any vehicle, we reduce the image processing area to eliminate the complex background by detecting the rear-lights as the license plates are in a certain range of these lights. Heuristic Energy Map (HEM) of the vertical edge information in the Region of Interest (ROI) is calculated and area with the dense edges is selected using a unique histogram approach which is considered to be the license plate. The proposed algorithm is tested on 855 images from various countries including China, Pakistan, Serbia, Italy and various states of America. Experimental results show that the proposed method is able to detect license plates 90.4% of times despite of complex backgrounds in 0.25 s on average that can achieve real time performance.  相似文献   
983.
特殊教育是九年制义务教育不可分割的一部分,培智学校是特殊教育学校中占比最大的学校。目前我国培智学校普通教学空间的设计基本遵照普通中小学教学空间,对智力障碍学生的针对性不足。文章基于调研得出的培智学校教学空间的现状,分析得出教学发展对功能空间的需求,据此提出教学空间的功能组成、空间规模和组合模式。认为培智学校的建设应与时代发展相吻合,不宜保守但也不能不计国情过度超前。  相似文献   
984.
导线不均匀覆冰和不同期脱冰会使线路发生跳跃,导致相间短路[1]。防脱冰改造施工中新型相间间隔棒可以有效地抑制脱冰跳跃。文中主要介绍了防脱冰改造施工中新型相间间隔棒的施工新工艺,运用此施工新工艺可以有效缩短停电施工改造时间,且对类似工程技术改进具有一定的参考价值。  相似文献   
985.
In this paper, the development of data-driven design of process monitoring and fault diagnosis (PM-FD) systems is reviewed and some recent results are presented. A major objective of this work is to sketch a process input–output data based framework of designing PM-FD systems for dynamic processes. The main focus of our study is on the data-driven design of observer-based PM-FD systems, which are, thanks to their high robustness and real-time ability, suitable for industrial applications.  相似文献   
986.
本文运用中国传统造园的思路,采用不拘一格的艺术手法,在有限的空间内点缀假山、树木,安排亭台楼阁、池塘小桥,创造出具有诗情画意的电厂厂前建筑景观。  相似文献   
987.
Currently, few general methods have been suggested to quantitate the imperceptibility among var- ious hiding algorithms. Especially, it is a challenge to quantitate the imperceptibility of the hiding-vector, which is consisted of orthogonal hiding algorithms in the multi- dimensional hiding space. In this paper, a novel model of general imperceptibility quantitation was proposed. Ac- cording to this model, a quantitation method based on the relative entropy was designed. It is proved under this quantitation method that there exists the global maximal imperceptibility for any specified hiding-vector capacity. An optimization algorithm was proposed to approach this maximum by adjusting the allocation of secret message into each components of the hiding-vector. Experiments with VoIP and bitmap multi-dimensional hiding space validated the effectiveness of the designed quantitation method and the proposed optimization algorithm.  相似文献   
988.
As some cities grapple with economic decline and depopulating neighborhoods, a number of academics and professionals have focused their attention on the causes, conditions and patterns of the resultant vacant land, whereas others lay out broad programmatic, institutional, fiscal and design responses to address vacancy on site or citywide scales. We find that, regardless of condition and context, most responses advocate complex, officially sanctioned, formal programs and policies that call for or depend on implementation over several multi-year phases. While laudable in scope, we question whether “permanent” solutions are appropriate given the widely varying causes, durations, contexts and patterns of vacancy and the inability of similarly scoped government-led programs to thus far achieve intended goals or improve local quality of life. We present examples that make the case for temporary, incremental, flexible and experimental responses to urban vacant land, then conclude by outlining the potential benefits and drawbacks of this temporary use model.  相似文献   
989.
In this paper, an adaptive sliding mode (ASM) scheme is proposed for fault identification and fault‐tolerant control of near space vehicles (NSVs). First, the attitude dynamic model is introduced, and a baseline controller based on reference sliding mode scheme is designed in the case of no faults. Then fault parameterizations with actuator dynamics is presented for several classes of faults: lock‐in‐place, float, hard‐over, and loss of effectiveness. On the basis of adaptive observer design, fault parameters can be accurately estimated on‐line. Furthermore, an ASM fault‐tolerant controller is designed for both cases of actuator dynamic faults and control effector damage. Finally, simulation experiments show that the proposed ASM scheme is able to quickly and accurately identify faults and reconfigure the controller, resulting in excellent overall system performance. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
990.
This paper deals with the estimation of the noise covariance matrices of systems described by state‐space models. Stress is laid on the systematic survey and classification of both the recursive and batch processing methods proposed in the literature with a special focus on the correlation methods. Besides the correlation methods, representatives of other groups are introduced also with respect to their basic idea, estimate properties, assumptions and possible extensions, and user‐defined parameters. Common and dual properties of the methods are highlighted, and a simulation comparison using exemplary MATLAB implementations of the methods is provided.  相似文献   
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