基于JN5139的农田无线传感器网内数据融合研究

在无线传感器网络中,各个节点的存储能力、通信能力、计算能力及能源的供给都十分有限,因而运用网内数据融合算法消除冗余数据,减小数据传输量,从而达到节省功耗、延长节点生命周期、提高数据采集效率和准确度的目的。介绍了系统结构及主要模块JN5139,采用简单滑动平均法、指数平滑法及自回归滑动平均模型(ARMA),在分析大量WSN数据的基础上,利用时间序列对数据进行建模预测,提出了适合WSN的数据处理模型并用Mat Lab进行仿真,之后将程序烧写到节点中进行试验。试验表明:该方法在保证采集数据可靠性的前提下有效地减少了网络的耗能,延长了网络的生命周期。     

基于时空双序列分析的温室WSN故障诊断

根据温室无线传感器网络(WSN)所采集数据在时间和空间上具有很强的相关性,从温室无线传感器网络基本结构出发,在分析WSN原始数据的基础上,通过对时空序列样本信息的预处理,分别建立了时间和空间故障诊断数学模型,据此分析传感节点的工作状态,给出了温室WSN故障诊断的综合算法.研究结果表明,该故障诊断方法能够及时、有效地发现温室WSN的异常并诊断出故障节点,提高了WSN工作的可靠性.     

基于时空双序列分析的温室WSN故障诊

根据温室无线传感器网络（WSN）所采集数据在时间和空间上具有很强的相关性,从温室无线传感器网络基本结构出发,在分析WSN原始数据的基础上,通过对时空序列样本信息的预处理,分别建立了时间和空间故障诊断数学模型,据此分析传感节点的工作状态,给出了温室WSN故障诊断的综合算法。研究结果表明,该故障诊断方法能够及时、有效地发现温室WSN的异常并诊断出故障节点,提高了WSN工作的可靠性。     

电气自动化技术在温室大棚中的应用研究

以温室大棚内环境参数的监测过程为研究对象,利用电气自动化技术搭建温室大棚环境参数监测系统,采用相关传感器对环境参数进行采集,通过GPRS通信方式将数据传输至不同的采集节点,并采用主采集节点对环境参数数据信息进行汇总,在远程数据传输单元中发送至主控制器,与设定的阈值进行对比,生成执行机构控制指令。试验结果表明：温室大棚环境参数监测系统能够有效对采集数据进行传输,同时准确稳定地对温室内各项环境参数进行监测。     

基于事件驱动与数据融合的温室WSN节能传输模型

针对温室内环境信息变化缓慢、冗余度大和时间空间相关性强的特点,提出了基于事件驱动与支持度融合的温室环境监测无线传感器网络(WSN)的节能传输模型。利用所建立的数据节能传输模型进行了温室环境试验,结果表明采用基于事件驱动的数据传输模型能够减少83.8%数据传输次数,基于支持度函数的数据融合能够根据数据之间的关联程度计算出各原始数据的加权值,融合效果优于算术平均值。     

基于图论的温室WSN测控系统冗余节点部署算法

针对温室无线传感器网络(WSN)测控系统的漏斗效应问题,提出负载平衡的冗余节点部署算法(RN-DA)。RNDA根据节点负载情况配置一定数量的冗余节点以平衡网络能耗,把节点下一跳选路概率作为权值引入图论,提出源节点数据经m跳到达目的节点概率的定理,为研究网络数据传输提供了一种有效方法。理论分析和仿真结果表明,RNDA既能明显延长网络寿命,又能有效平衡网络节点的能耗。     

基于WSN的智能温室大棚自动定点喷灌系统

针对传统温室大棚灌溉智能化和自动化水平低的问题,采用无线传感器网络WSN技术设计了智能温室大棚自动定点喷灌系统。系统主要由监控中心上位机、多个温湿度监测和电磁阀控制节点、密封储水罐压力监测节点、充压机和水泵控制节点组成。通过温湿度传感器获取土壤表层的温度和湿度数据,并经过ZigBee网络将该节点ID和数据打包实时发送至监控中心上位机,一旦监测到的湿度低于设置的阈值时,会控制对应该区域的电磁阀开启进行喷灌,同时控制充压机保持储水罐内的压力为恒定值。试验表明,该系统能准确获取土壤表面的温湿度数据,实现了整个温室大棚的定点喷灌和密闭储水罐的自动补水功能。     

基于无线传输的温室环境智能监测与报警系统

设计了一种基于ZigBee和GPRS无线传输的温室环境智能监测和报警系统,有效地解决了温室环境监测过程中布线困难、报警方式单一、成本高、不能稳定运行等缺点。以微型处理器和ZigBee通讯节点作为采集节点,以ZigBee和GSM/GPRS通讯模块作为汇聚和远程数据传输的网关节点,采用树状的组网方式完成短距离的数据汇聚,通过GPRS完成远程数据传输;在服务器上配置了数据库和网页远程服务,用户通过用户终端远程访问温室作物实时监测数据。本文实现了节点和服务器的双向数据通讯,使服务器可以远程配置单个采集节点的报警上下阈值和采集时间周期;完成了温室环境的智能报警;加入了系统可靠运行机制,使系统可以连续、稳定地运行。经试验验证,系统可以满足温室作物生长环境的智能监测和报警需求。     

WSN土壤湿度采集节点电压补偿方法研究

针对适用于WSN土壤湿度采集节点的EC-5传感器对电源电压敏感的问题,从传感器工作原理入手分析电源电压引起检测误差的来源,且发现当传感器各项参数确定后,这种误差随着被测土壤湿度增大而增大。采用CC2430芯片作为WSN信息传输节点,建立具有多节点的上下位机WSN土壤湿度采集系统,以节点电压u和被测土壤实际湿度θ为对象,运用神经网络对采集节点中非线性土壤湿度传感器系统进行逆向建模,在上位机上实现由电源电压引起EC-5传感器检测误差的补偿,实验结果表明,该方法能有效地减少节点电池电压变化对WSN土壤湿度采集精度的影响。     

土壤湿度采集节点电压补偿方法——基于最小二乘支持向量机

针对适用于WSN土壤湿度采集节点的EC-5传感器对电源电压敏感的问题,从传感器工作原理入手,分析电源电压引起检测误差的来源,且发现当传感器各项参数确定后,这种误差是随被测土壤湿度增大而增大的。采用CC 2 4 3 0芯片作为WSN信息传输节点,建立具有多节点的上下位机WSN土壤湿度采集系统,以节点电压和被测土壤实际湿度为对象,运用最小二乘支持向量机对采集节点中非线性土壤湿度传感器系统进行逆向建模,在上位机上实现由电源电压引起EC-5传感器检测误差的补偿。实验和仿真结果表明,该方法能有效地减少节点电池电压变化对WSN土壤湿度采集精度的影响。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。