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目前随着交通复杂程度的不断增大,当前的交通通信系统无法满足车辆间远程、及时通信的要求,降低了行车安全性。为此,设计一种基于基于ARM920T的嵌入式远程及时通信系统,介绍了系统需实现的功能,以ARM920T芯片为核心,利用通信管理机完成数据交换,结合嵌入式系统平台完成系统硬件设计。基于ARM920T的车辆通信子系统通过车辆通信对车辆的行驶进行及时的路线跟踪、碰撞提醒,状态监测以及历史轨迹显示回放。对通信子系统进行设计,子系统分别为车辆定位系统以及车辆调度系统,构建车辆通信模型,进一步实现车辆精准远程通信,并结合蚁群算法对车辆通信模型进行求解。实验结果表明,所设计通信系统不仅通信精度高,而且成本较低,实时性优。 相似文献
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为实现对循环水水质的远程监测,设计并开发了一种基于嵌入式技术的热力站远程水质监测系统的监测终端。监测终端由水质传感器、GPRS模块、通信转换模块及嵌入式开发板组成。嵌入式开发板以ARM11系列的Tiny6410为硬件基础,并嵌入WinCE系统作为软件平台,同时加入SQLite数据库以实现将水质传感器采集到的氯离子、PH值、溶解氧等参数的本地存储、查询及图表显示。最后监测终端通过GPRS模块与数据中心建立无线连接,接收数据中心的配置命令,并将现场测得数据发送到远端数据中心。调试结果表明:远程监测终端实现了循环水水质远程监测的功能要求,对于实现水质自动化监测具有一定的理论意义和实用价值。 相似文献
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为了提高图像边缘检测的性能,缩短处理时间,提出了一种基于FPGA的实时视频边缘检测系统。该系统以EP2C8Q208C8为实验硬件平台,首先采用摄像头OV7670获取模拟视频数据,双端口SDRAM实现对图像数据的缓存,利用FPGA并行处理的特点,采用Verilog HDL硬件描述语言实现改进的Canny边缘检测算法,最终实现在VGA显示屏上显示图像边缘的效果。实验结果表明,较传统的边缘检测算法,该系统边缘检测定位精度高,对噪声的抗干扰能力强,能够准确快速的输出图像边缘信息。 相似文献
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将ARM与DSP相结合,设计并实现了一套嵌入式实时视频传输跟踪系统;该系统以集成ARM和DSP双内核的OMAP3730作为核心处理器,首先通过ARM上搭载的Linux操作系统实现基于V4L2的图像采集功能,然后调用DSP完成H.264视频编码,压缩后的图像由基于实时流传输协议的流媒体服务器传输至远程计算机端解码并显示,最后利用camshift跟踪算法实现对运动目标物体的实时跟踪。该系统是小型无人机自主导航与控制的视觉导航以及以无人机为平台的运动目标检测的基础,有很好的应用前景。 相似文献
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为了实现漆包机生产的远程监控,设计了一款基于Web的实时漆包机远程监控平台。该平台使用模块化,可扩展的设计方案,采用了Spring MVC的后台Web应用程序框架,基于Modbus协议的数据交互,Ajax方式的网络数据异步提交以及无刷新的图表显示技术。传统的监控平台只能通过以太网在企业内部访问,而该平台可接入互联网,可实现随时随地通过电脑及或者移动终端对生产设备各部分的温度点、电机风机转速、耗电量统计的实时监视,对温度的上下限及电机转速进行远程控制,接收设备状态异常的实时报警,数据存储分析。实验测试表明,该平台的实时性和稳定性均能达到车间生产的要求。 相似文献
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Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity. 相似文献
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The differences of the pitch and duration of Chinese syllables between Putonghua (PTH) and Taiwan Mandarin (TM) were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that: For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM. 相似文献
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Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones. 相似文献
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JIA Duojie 《中国物理C(英文版)》2008,32(7)
It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1]. 相似文献
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A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance. 相似文献
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Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use. 相似文献
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Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122: 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM (Scanning Electron Acoustic Microscopy) signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α (α is the radius of the focused electron beam). Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally. 相似文献
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Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies. 相似文献