Practices with technology: learning at the boundary between study and work

A study of part‐time student experience of university courses delivered using a range of technologies found that information and communication technology enabled students to move between study and work experience to the benefit of their learning in both contexts. Technology‐based study activities enabled students to participate in learning both as a student and as a member of a practice or work context. Given the increasingly pressured lives of all students in higher education and their aspirations for employment after graduation, this suggests that we would benefit from taking their relationship to work and professional practice into account more directly, in deciding how to integrate technology into their study experience. Teacher conceptions of technology as a tool primarily for information delivery and discussion need to expand to recognize that it can be used to construct learning experiences situated in roles, skills and interactive environments that enhance students' ability to make transitions across the boundaries between contexts of study and work.     

新时期云南农业经济发展战略的思考

新世纪中国经济发展的第二步战略目标已经实现 ,中国经济发展进入新的阶段 ,国家开始实施西部大开发战略。云南农业经济的发展如何适应新形势、抓住机遇 ,这是制定农业经济发展战略必须考虑的因素。作者依据当前社会、经济发展的时代背景 ,结合云南农业经济的现状 ,试图对云南农业经济发展战略及其重点的选择等问题进行探讨     

我国农业机械化评价指标体系设置研究

农业机械化指标体系的准确设置和正确运用将有助于评价标准的统一性 ,便于使用同一的计量尺度计算和分析农业机械化的作用效果 ,评价农业机械化发展水平。本文通过对农业机械化评价指标体系的属性、功能以及量化标准的理论研究与分析 ,提出了构建我国农业机械化评价指标体系框架的初步设想     

运城地区可持续发展农业工程信息资料检索系统研究

采用 Win95操作系统 ,以 VB为开发工具 ,对运城地区农业工程信息进行快速检索并长期存储。该系统成本低、实用性强 ,人机交换界面使用方便 ,不需专业培训 ,为大型农业建设工程信息资料的检索和存储开辟了一条新的途径     

A socioeconomic model for managing water resources in Alicante,southeast Spain

The study analyzes variables that influence the water management model based on a simultaneous relationship between competing demands in the Marina Baja of Alicante, using a methodology that directly links together urban and irrigation demands, making them relevant to each other from a socioeconomic point of view. The paper identifies the relevant variables of this model and the agent behaviour in a closed and joint system. It also aims to demonstrate that by considering water demands for different yet simultaneous uses and regarding clean and reclaimed waters as integrated resources, the system could remain in equilibrium without external water supplies.     

水利对粮食生产贡献率的认识与思考

针对目前很多人对农业科技进步贡献率和水利对粮食生产贡献率的不同认识,从发展历程、概念内涵、测算思路方法等方面,剖析了二者差异,认为二者在测算范围上存在大口径与小口径的差异,在测算对象上存在增量与总量的差异,在测算指标上存在产值与产量的差异,在测算方法上存在余值法与有无对比法的差异,为正确认识这两个指标提供了参考。     

基于改进模拟退火算法的均匀设计表构建

当 为偶数时,使用好格子点法不能产生因素数较大的设计表,且只能在解空间的子空间内产生设计表,所产生的设计表无法保证最均匀。针对上述问题,引入智能计算方法,包括粒子群优化算法和改进的模拟退火算法。对3种算法的优化性能进行比较,结果表明智能算法可以对较大范围的因素数产生设计表,与好格子点法相比,智能算法能够得到均匀性更好的设计表,并且相对粒子群优化算法,改进模拟退火算法构建的均匀设计表的偏差更小。     

面向精准农业的无线传感器网络研究进展

概括了当前国内外对精准农业中无线传感器网络的研究进展与应用现状,并分析了尚需解决的问题,给出了无线传感器网络今后发展的建议。最后,对精准农业中无线传感器网络的发展趋势做了展望,指出以无线传感器网络技术为基础的农业物联网是精准农业的发展方向。     

农用棚膜用防流滴剂、防雾剂开发应用及其进展

概述了温室塑料棚膜的流滴、雾化机理和防流滴、防雾化技术及其研究进展。介绍了防流滴剂的主要品种及其组成,防雾剂的主要品种及其特性,并列举了一些实例。针对技术上及应用上出现的问题,提出了一些建议。     

Multilevel Approach for Optimizing Land and Water Resources and Irrigation Deliveries for Tertiary Units in Large Irrigation Schemes. I: Method

This paper presents the area and water allocation model (AWAM), which incorporates deficit irrigation for optimizing the use of water for irrigation. This model was developed for surface irrigation schemes in semiarid regions under rotational water supply. It allocates the land area and water optimally to the different crops grown in different types of soils up to the tertiary level or allocation unit. The model has four phases. In the first phase, all the possible irrigation strategies are generated for each crop-soil-region combination. The second phase prepares the irrigation program for each strategy, taking into account the response of the crop to the water deficit. The third phase selects the optimal and efficient irrigation programs. In the fourth phase of the model, irrigation programs are modified by incorporating the conveyance and the distribution efficiencies. These irrigation programs are then used for allocating the land and water resources and preparing the water release schedule for the canal network.