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Search Results: 1 - 10 of 53683 matches for " 曹雪虹 "
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基于双目立体视觉的图像面积测量算法与技术
Algorithm and Technology of Image Area Measurement Based on Binocular Stereo Vision
 [PDF]

车娟娟, 张健,
Computer Science and Application (CSA) , 2013, DOI: 10.12677/CSA.2013.37A001
Abstract:
本文基于双目立体视觉测距原理,用普通的USB摄像头搭建双目立体视觉系统,提出了图像面积的非接触在线测量方法。首先对摄像头进行标定,得到摄像头的内参数,然后根据OpenCV的模板匹配算法,求出两幅图像中对应匹配点的水平视差,得到距离参数,最后根据平行双目视觉的成像原理,求得实际图像与其在成像平面上的图像之间的空间几何关系,进而求出图像的实际面积。该方法实现简单、成本低、实时性好。经过实验验证,该算法在一定测量范围内达到精度要求。
>A binocular stereo vision system with a common USB camera is developed based on the distance measurement principle of binocular stereo vision, and the non-contact and on-line inspection method for the area of image is studied. First, we calibrate the camera and obtain the internal parameters of the camera. Second, horizontal parallax of the cor- responding points in two images is calculated by template matching based on OpenCV, and then the distance parameter is obtained. Finally, we find the spatial geometrical relationship between the image of the imaging plane and the actual image, and then the actual area of image is gotten. This method is easy to realize with low cost and real-time perform- ance. The experiment indicates that the algorithm meets the accuracy requirements within certain range of measurement.
OFDM系统中的联合同步和信道估计

电子学报 , 2006,
Abstract: 在OFDM系统中,由于定时恢复、频率同步和信道估计之间存在密切联系,时延和频偏的估计误差会影响信道响应估计的准确性.本文采用IEEE802.11a无线局域网系统标准定义的训练序列进行联合估计.考虑系统性能优化和算法简化,将处理过程分成两步,首先得到粗的同步和信道响应估计,再利用得到的结果进行细同步和信道估计.实验结果显示信道估计精度高,系统误码率低.
面包保鲜剂中单硬脂酸甘油酯的含量测定方法的探讨
,
食品科学 , 1986,
Abstract: ?<正>目前食品工业不断发展,面包的质量有了很大的提高,质软疏松,保鲜期长,其中面包保鲜剂——单硬脂酸甘油酯(以下简称单甘酯)的应用尤为广泛,我国食品添加剂
基于正交空时编码的盲信道估计
,姚维坚
电子学报 , 2009,
Abstract: 本文从MIMOOSTBC-OFDM系统的频域出发,利用编码的正交特性建立数学模型,采用归一化问题的最小值求解思想,提出了一种基于二阶统计特性的子空间信道盲估计算法,减少了数据的运算量.为了消除求解过程中出现的多个模糊度,本文采用预编码技术,提高了信道估计的精度.仿真实验证明,该估计算法收敛性好,对发送信号无特殊要求,不增加传输带宽.
blastofdm系统中基于qr分解的检测算法
炎焱,,贾锋
南京邮电大学学报(自然科学版) , 2006,
Abstract: 将blast(分层空时编码)和ofdm(正交频分复用)相结合,利用无线信道的多径传播特性产生并行空间信道,从而提高数据的传输速率,抵抗频率选择性衰落,并提出了一种基于qr分解检测的抑制连续干扰消除中误码扩散的检测算法。仿真证明,这种算法较qr分解检测算法误码率性能有了较大的提高,与排序qr分解检测算法相比误码率性能也有所改善,计算复杂度也略占优势。
一种新的基于判决反馈的ofdm系统信道估计方法
苏岚,,郭士伟
南京邮电大学学报(自然科学版) , 2008,
Abstract: 提出了一种基于判决反馈机制的信道估计方法,采用少量导频估计出初始信道信息,再从接收端检测出的符号中选取一组包含了少量错误的符号作为准导频,反馈到信道估计器,与初始的导频一起构成数量更多的导频序列,经过几次迭代,达到提高信道估计精度的目的。为提高初始估计的精度,信道估计采用了一种频域分集的方法。计算机仿真表明,在多径瑞利衰落信道下,本文的方法可以在较低的复杂度下有效地提高信道估计的精度,在mmse接收条件下,系统具有良好的误比特率(ber)性能。
不对称速率双向中继系统的中继选择及功率分配
杨洁,,芮雄丽,陈瑞
南京邮电大学学报(自然科学版) , 2014,
Abstract: 研究了不对称速率双向放大转发中继系统中的中继选择及功率分配问题。以中断概率作为约束条件,以系统总发射功率最低为目标,通过将几何规划问题转化成凸优化问题推导了功率分配的闭式解。在此基础上,提出了最小化最低总功率的中继选择标准。最后给出了中继选择与功率分配联合优化策略及实施步骤。仿真结果表明在给定的中断概率门限下,文中的联合优化策略能显著降低系统的功率消耗。
一种总发射功率最小化的协作MAC协议
Cooperative MAC protocol based on total transmission power minimization

芮雄丽,,杨洁,陈瑞
- , 2015,
Abstract: 针对能量受限的无线传感器网络,提出了一种能降低网络能耗的跨层协作MAC(Medium Access Control)协议。文中首先分析了直接传输和协作传输下的总发射功率,理论分析表明,在一定的误码率限制下,引入合适的中继节点能降低网络总的发射功率。在802.11DCF(Distributed Coordination Function)的基础上,通过监听邻居节点控制包,获得各信道的状态信息,并选出使总发射功率最小的最佳中继,同时扩展CTS(Clear To Send)、增加HTS(Helper ready To Send),完成自适应的协作传输。仿真表明,该MAC协议能有效降低网络能耗,延长网络寿命。
A cooperative medium access control (MAC) protocol based on total transmission power minimization is proposed to reduce the network energy consumption in energy limited wireless sensor networks. With theoretical analysis, appropriate relay nodes can reduce the total transmission power of the network and the bit error rate of the destination node constrained at a certain target level. Based on the 802.11 distributed coordination function (DCF), the channel state informations (CSIs) are estimated according to the strength of control frames and the best relay by minimizing the total transmission power of the network is selected. Furthermore, to design an adptive cooperative transmission scheme, the frame format of clear to send (CTS) is extended and a helper ready to send (HTS) frame is introduced. Simulation results show that the proposed MAC protocol can effectively reduce the energy consumption and extend the network lifetime
基于泊松洞过程建模的异构蜂窝网络信干比增益与近似覆盖率分析
Analysis on signal to interference ratio gain and approximate coverage in heterogeneous cellular networks based on Poisson hole process modeling

鲍梓永,杨洁,胡晗,
- , 2018,
Abstract: 移动通信业务的高速增长使得传统同构蜂窝网络结构不能满足用户对通信质量的要求,而异构网络架构可以有效解决这种问题。文中对泊松洞过程下异构蜂窝网络的覆盖率进行研究。首先,利用泊松洞过程(Poisson Hole Process, PHP)对异构蜂窝网络进行建模;然后以信干比(Signal to Interference Radio, SIR)分布为研究目标,利用泊松点过程的近似SIR分析方法,推导出PHP模型下网络SIR增益的具体表达式;最后,通过缩放泊松网络的信干比门限得到PHP模型下的近覆盖率。通过实验仿真,验证了所求近似增益的正确性。
The rapid growth of mobile communication services makes the traditional homogeneous cellular network structure be unable to meet users’ requirements for communication quality, but the heterogeneous network architecture can effectively solve this problem. This paper studies the coverage of heterogeneous cellular networks in the Poisson hole process(PHP). Firstly, the heterogeneous cellular network is modeled by Poisson hole process. Then, the signal to interference radio (SIR) distribution is used as a research target, and the approximate SIR analysis using the Poisson point process is used. In this way, the concrete expression of the network SIR gain on the PHP model is derived. Finally, the near coverage ratio on the PHP model is obtained by scaling the SIR in the Poisson network. the experimental simulation verifies the correctness of the approximated gain
樱桃及其产品开发利用现状
Current Situation for Development and Usage of Cherry and Its Related Products
 [PDF]

苏丽,
Hans Journal of Food and Nutrition Science (HJFNS) , 2016, DOI: 10.12677/HJFNS.2016.53011
Abstract:
樱桃果实多汁,色鲜味美,营养丰富,食用价值和医用价值极高,具有显著的抗病保健功效。近年来国内外越来越重视樱桃及其产品的开发利用,本文指出樱桃开发加工产品多集中在传统樱桃果酒及樱桃罐头的开发,市场上可见的其他樱桃加工产品还有樱桃果汁、果醋、果酱等,为樱桃的利用发展趋势及多元化产品的开发提供科学依据,并对樱桃开发前景进行展望。
Cherry is juicy, colorful, flavorful and tasty with high edible value and medical value and it has sig-nificant effects of disease resistance and health care. In recent years, both at home and abroad more and more attention is paid to the development and utilization of cherry and its products. This paper points out that cherry processing products are more concentrated on the traditional cherry fruit wine and canned cherries, as well as other visible cherry processing products in the market, such as cherry juice, vinegar, jam etc., which provides scientific basis for its development trend and development of diversified products, and forecasts the development prospects of the cherry.
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