基于农业信息化的垂直搜索引擎的分析与设计

以湖南省农业信息化综合服务平台开发需求为背景,在分析垂直搜索引擎具体功能的基础上,利用Java,Oracle,Tomcat实现了一个基于农业信息化的垂直搜索引擎。该系统使用Servlet,JSP,JSTL等技术主要实现了对农业网站新闻和图片等的抓取,最后与农博网等系列网址进行了对比测试。运行结果表明,该系统达到了灵活抓取与良好扩展的目的。     

本体在农业信息检索中的应用

针对全文检索与数据检索的弊端,设计了基于本体的语义检索系统的框架.该框架以本体的定义和分类为研究基础,构建出一个农业领域本体的语义网络,便于逻辑推理;选择RDFS作为本体描述语言,生成RDFS的关系元数据文件,最终形成了基于农业领域本体语义信息检索系统的框架.     

基于知识网络的农业信息服务系统研究

目前,我国虽然建立了一些农业信息网站,但面临提供的农业信息服务质量不高及信息获取、信息组织与信息检索效率低等问题。为此,将农业知识分为农业组织知识、农业个体知识、农业方法知识以及运用本体论方法构建了农业知识本体,提出了一种基于知识网络的农业信息服务系统模型,并深入研究了构建农业知识网络系统的关键处理过程,从而揭示了农业知识存在、组织、应用和变化情况,为实现农业知识的有效管理和高效应用提供了支持。     

领域本体模型构建与信息检索方法研究

传统的信息检索主要是利用关键词进行匹配检测的,在信息检索过程中时常出现检索结果不全等问题.通过引入了本体论、构建本体框架,利用概念相似度的信息检索方法,从而提高信息检索的查全率和查准率.     

大豆垂直搜索引擎的研究与设计

随着互联网技术的发展,搜索引擎的垂直化得到了广泛的研究和应用.为此,以用户对大豆领域相关信息的需求为研究背景,在已有垂直搜索引擎的理念和技术基础上,对大豆垂直搜索引擎进行了研究和设计.同时,提出了大豆垂直搜索引擎的体系结构,并对网页信息采集、索引和管理与审核模块进行了详细的分析和设计,最终为系统的实现提供了解决方案和理论基础.     

基于本体的农业信息服务系统

领域信息服务系统是人工智能领域的一项研究热点.为了让用户及时准确地得到解决方案,解决搜索引擎返回信息过多及问答系统知识瓶颈的问题,提出建立一个用户与专家非实时交流的平台,实现问题咨询与解决方案的双向对应.为此,较全面地分析了农业信息服务系统的系统框架与功能,对其涉及的关键问题-基于本体的农业领域知识库的建立和问题解答过程中问题状态的控制机制进行了深入的讨论.     

农业机械垂直搜索引擎的设计与实现

专业垂直搜索引擎只对行业信息资源进行深层次的整合和加工,通过研发面向农业机械垂直搜索引擎来整合互联网上丰富的农业机械行业数据资源,为农业机械工作者和信息服务人员提供高效、专业和人性化的服务。本文通过介绍垂直搜索引擎的定义、工作原理及发展趋势,结合互联网上农业机械信息资源分布的特点,描述了面向农业机械垂直搜索引擎的整体架构设计,并深入讨论了研发面向农业机械垂直搜索引擎所涉及到的关键技术及应用。     

基于本体的Web零件库数据描述规范

提出了一种基于本体的Web零件库数据描述规范,结合零件族和事物特性表建立了Web零件库的框架,解决了零件库数据共享和重用的问题。通过扩充零件的CAD模板、事物特性表和本体库实现了零件库动态扩充。建立了基于零件本体的多层次检索模型,通过垂直匹配与水平匹配两次匹配来提高查询准确率。建立了一个Web零件库原型系统,验证了数据描述规范方法的可行性。     

忻州地区机械化旱作农业的实践与思考

机械化旱作农业由于其集约性和技术含量高已成为旱区农业增长方式的重要途径。近几年来，我们根据忻州地区旱区的特殊自然资源、气候条件，在干旱和无灌溉的情况下，利用天然降水，通过节水、生物、农艺和机械化的有机结合，实现水、土、光、热资源的合理配置，走出了一条...     

旱地保护性耕作技术在南疆地区的应用

保护性耕作技术在南疆地区得到大面积的试验与推广.事实证明,保护性耕作在抗旱增产、蓄水保水、培肥土壤、节本增效和实现生态农业等方面的优势显著,特别是对于防止土壤荒漠化,减轻和缓解干旱的不利影响有很重要的作用.通过秸秆直接归还土壤,可以改善土壤的理化性状,解决旱区农业生产中的主要问题,实现旱区农业的可持续发展.为此,分析了南疆地区保护性耕作的现状及应用,阐述了保护性耕作的发展趋势.     

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。