时序分析在排种轴转速检测数据处理中的应用

利用CCD摄像机获取气吹式精密排种器排种轴视觉检测样本,通过图像处理获得转速序列,在分析转速序列特点的基础上,采用时序分析方法研究排种轴转速。利用转速序列数据计算各种转速下的自协方差函数、自相关函数和偏自相关函数,选用AR模型进行转速序列的分析。将实测数据代入AR模型求得模型参数,应用模型进行转速序列数据拟合(以45 r/min为例),获得模型拟合值、残差序列。残差序列和模型拟合优度分析结果表明,模型预测的残差最大值为19.920 6,并且有83.83%的残差在允许值±6.912 312 r/min范围内;模型拟合度为74.631 2%,标准方差为0.050 136,模型系数t检验结果为16.805 28,显著性水平0.000通过t检验。     

基于GPRS的单轨林果运输车无线定位测速方法

为及时掌握单轨林果运输车位置及速度信息,提出一种基于GPRS无线通讯技术的单轨林果运输车定位及测速方法.采用嵌入式处理器ARM9作为运输车车载控制仪及远距离地面控制器的核心处理器,并利用旋转编码器提供单轨车位置及速度原始信息,通过GPRS技术实现无线数据传输及控制.阐述了该定位测速方法的部分软件及硬件设计,并对无线数据...     

Look at what they do – a revised approach to communication strategy towards private forest owners

Private forest owners in Sweden and other countries are becoming an increasingly heterogeneous group as regards their experience and knowledge of forestry. Over the past decade, a number of studies have been conducted with the aim of describing different aspects of forest owners. However, little attention has been paid to the owners' self-activity and how they learn. With the overall aim of exploring the relationship between self-activity and knowledge to use it as a starting point for new recommendations for planned communication towards forest owners, this study examines the extent and type of the work different categories of private forest owners perform, and from whom or where they learn. An analysis of data from a mail questionnaire and from the Database for Forest Owner Analysis showed that self-activity is common in all categories of owners but more frequent among male and resident forest owners. Forest owners have relatively few knowledge sources. Besides being self-taught, the most common ways of learning are from their fathers and from attending forest days. The study also shows a strong connection between self-activity and self-estimated knowledge of forestry. The recommendation for communication planning is therefore to use the extent and type of self-activity among different groups of forest owners as a point of departure for planning communication strategies.     

用延时法调整8051单片机串行通信的波特率

本文根据8051单片机串行口的工作原理,提出通过编程调整所需波特率的方法——延时法。结果表明．此法避免了修改硬件的麻烦,也可获得较精确的波特率。     

中国标准连续出版物号著录规范浅析——以畜牧、动物医学类期刊为例

为规范中国标准连续出版物号在期刊中的著录,查阅了31种畜牧、动物医学类期刊,以GB/T 9999-2001《中国标准连续出版物号》为标准,统计不规范著录格式,提出克服、纠正不正确、不规范的著录格式,正确编排印刷中国标准连续出版物号。     

Intraorganizational Communication: A Study of Communication/Interaction Among Core Subprograms of the Enugu State Agricultural Development Program,Enugu State,Nigeria

In recognition of the importance of communication in extension work and agriculture, this study assessed communication methods used among core sub-programs of the Enugu State Agricultural Development Program (ENADEP). Sixty-three staff were randomly selected to participate in the study. Statistical tools such as percentage, mean score, and factor analysis were used in data analysis. Findings show that a downward (top-down) communication flow was most common, with posters and workshops as primary communication tools. Technology review meetings and training were major situations in which communication occurred, while achievement of ENADEP objectives was the most important motive for communication. Communicator knowledge about subject matter was the top-rated factor that enhanced communication; security/credibility- and human/autocracy-related problems were major constraints to effective communication. The study recommends a de-emphasis on top-down communication approaches and encourages use of digital/information communication technology (ICT) tools to minimize the gap between generation and dissemination of information and its application.     

网络实时通信协议设计

依据实时通信系统和当前主要局域网的特点,提出并研究在多点接入网络中进行实时通讯的窗口来传输带时间限制的信息,它与传统窗口协议的ＩＥＥＥ８０２标准的不同之处在于详细考虑了时间限制,窗口的形成是以信息的最迟发送时间为基础。本协议的优点是,如果一个新到达信息的ｔｓ比系统中所有等待信息的ｔｓ小,则它就可以立即被传输。因此,该协议完成了优化的“最小疏密度优先”原则。     

家兔胚胎细胞核移植与连续移植

将发育不同时期的兔胚和移核胚的卵裂球细胞核与去核的成熟卵母细胞共同组成移核胚,通过中间受体培养和移植实验检验胚胎的发育能力。结果表明,（１）兔囊胚之前各个时期的胚胎细胞核均可使移核胚发育到囊胚;（２）胚胎极化前后的卵裂球参与组成的移核胚发育到囊胚的比例无显著差异。但极化后 ６４细胞胚的卵裂球与去核卵母细胞的融合率低于极化前的 ８细胞胚胎卵裂球;（３）兔 １６细胞胚与去核的卵母细胞组成的移核胚可以发育到期,产仔率为 ３．１６％ ;（４）兔移核胚卵裂球用于连续核移植,其后 ２ 代均可发育成囊胚,其中第 １ 代移核胚与第 ２ 代移核胚发育率相似,但显著高于第 ３ 代移核胚;（５）兔移核胚和各代连续移核胚卵裂球与去核卵的融合率无显著差异。     

深水养殖水质数据采集监测系统

深水网箱养殖技术目前已成为海产品养殖发展的一种趋势,对养殖海域造成的污染也日益严重,而传统的水质采集受到人工或移动网络覆盖范围的限制.为解决这一问题,该研究介绍了一种基于北斗“短信息”服务的水质环境数据采集、监测系统.结果表明,该系统能够实时地将不同天气、季节、海况等条件下获取的水质环境数据通过北斗导航系统网络实时发送回数据处理中心,便于对水质数据进行统计、分析以及预警.     

不同频率无线信道在针叶林中的传播特性

为了了解针叶林中不同频率无线信道在不同位置的传播性质,以中国林科院院内的白皮松林为例,通过信号发生器和频谱仪分别测试了不同高度水平方向、不同频率的信号传播特性以及不同高度针对某一水平测试点的传播特性.结果表明:在针叶林环境中,无线通信距离在在10~20 m时,信号强度与距离呈反比;通信距离在20~60 m时信号强度无明显规律,也无明显的衰减;通信距离超过60 m时,各频段信号强度衰减严重.433 MHz频段的无线信号强度显著高于其他频段,最适合用于针叶林环境中的无线通信.无线信号频率越高,信号波动越小,信号衰减越明显.本研究得出的针叶林中不同频率无线信道的传播特性为传感器网络在林中的部署提供了重要参考,对林业物联网组网研究与应用有重要意义.