基于特征筛选算法的数字土壤制图研究

平缓地带数字土壤制图中，环境协变量的选择是提高制图精度的关键。已有研究证明遥感影像可作为推理制图的辅助因子，而如何确定环境因子推理制图时各自的权重已成为现阶段研究的重点。选取湖北省麻城市乘马岗镇为研究区，采用3种特征筛选方法进行有效环境变量筛选，探索参与平原-丘陵混合区域制图的因子并确定其重要性，依据选择的相对稳定的指标，进一步探索提高土壤类型制图准确性的途径。根据141个野外独立样点的检验结果表明：在推理制图中，遥感因子在平原区域的重要性程度高于丘陵区域，且遥感因子中归一化植被指数(NDVI)和均值(Mean)较为稳定；基于递归特征算法的按地形推理制图精度最高为75.89%，分别高于ReliefF算法和基于Tree的特征筛选算法13.48%和4.97%；此外3种特征筛选算法制图结果中，按地形因子分区制图的精度均高于整体区域制图。因此，遥感因子作为辅助手段参与推理过程可有效提高制图精度。本研究采用的特征挖掘与机器学习算法对提升土壤制图精度具有一定的理论意义。     

知识经济与洛阳经济可持续发展

知识经济时代，洛阳经济可持续发展战略应该是：加大教育科研改革，全面实施“科教兴洛”战略，夯实知识经济的基础产业；扩大农业的知识资本投入量，促进农业产业化、企业化、资本化经营，实现农业知识化和现代化；得用新技术成果，对传统工业进行知识化改造，着力营造一批高新技术产亚，推动洛阳产业结构全面升级和优化。     

基于Web的造林专家咨询系统研究

利用新的信息技术,研究造林专家的造林决策方法,提出造林专家决策咨询系统的目的和功能,给出系统环境和结构、知识库和推理机的设计,建立一个基于网络的、适于不同地区的造林专家决策咨询系统,解决困扰着传统森林培育中的适地适树和造林设计问题.     

An overview of animal science research 1945–2011 through science mapping analysis

The conceptual structure of the field of Animal Science (AS) research is examined by means of a longitudinal science mapping analysis. The whole of the AS research field is analysed, revealing its conceptual evolution. To this end, an automatic approach to detecting and visualizing hidden themes or topics and their evolution across a consecutive span of years was applied to AS publications of the JCR category ‘Agriculture, Dairy & Animal Science’ during the period 1945–2011. This automatic approach was based on a coword analysis and combines performance analysis and science mapping. To observe the conceptual evolution of AS, six consecutive periods were defined: 1945–1969, 1970–1979, 1980–1989, 1990–1999, 2000–2005 and 2006–2011. Research in AS was identified as having focused on ten main thematic areas: ANIMAL‐FEEDING, SMALL‐RUMINANTS, ANIMAL‐REPRODUCTION, DAIRY‐PRODUCTION, MEAT‐QUALITY, SWINE‐PRODUCTION, GENETICS‐AND‐ANIMAL‐BREEDING, POULTRY, ANIMAL‐WELFARE and GROWTH‐FACTORS‐AND‐FATTY‐ACIDS. The results show how genomic studies gain in weight and integrate with other thematic areas. The whole of AS research has become oriented towards an overall framework in which animal welfare, sustainable management and human health play a major role. All this would affect the future structure and management of livestock farming.     

棕榈在孟加拉乡村传统利用——一种可持续的生物多样性管理手段(英文)

采用多级采样的方法研究了孟加拉国农村耕作区内棕榈树的传统利用模式和当地的管理经验。农民管理棕榈主要为获取树液产品,生产以糖为主的次生品。树液可直接用作饮料,也可加工成糖蜜或酒精饮料。7块不同地块为棕榈提供生长环境,20.40%的棕榈种植在果园内。尽管中等级的农民拥有多数棕榈(33%),但是主要管理棕榈的是没有土地的农民,他们靠棕榈维持生计。这些农民将自己的智慧应用到棕榈管理当中,从种植到开孔取树液再到产品加工。如果能更科学地管理棕榈,加上农民的智慧,棕榈业将会对当地经济发展起到重要作用,也会丰富当地生物多样性。     

Towards the sustainable intensification of agriculture—a systems approach to policy formulation

The sustainable intensification of agriculture involves providing sufficient food and other ecosystem services without going beyond the limits of the earth’s system. Here a project management approach is suggested to help guide agricultural policy to deliver these objectives. The first step is to agree measurable outcomes, integrating formal policy goals with the often much less formal and much more diverse goals of individual farmers. The second step is to assess current performance. Ideally, this will involve the use of farm-scale metrics that can feed into process models that address social and environmental domains as well as production issues that can be benchmarked and upscaled to landscape and country. Some policy goals can be delivered by supporting ad hoc interventions, while others require the redesign of the farming system. A pipeline of research, knowledge and capacity building is needed to ensure the continuous increase in farm performance. System models can help prioritise policy interventions. Formal optimization of land use is only appropriate if the policy goals are clear, and the constraints understood. In practice, the best approach may depend on the scale of action that is required, and on the amount of resource and infrastructure available to generate, implement and manage policy.     

Renaturing cities: from utopias to contested realities and futures

Renaturing urban environments is a transformative pathway for urban sustainability that can be leveraged for collaborative research and planning to reverse long trends of ecosystem degradation. People-nature connections need to be reinforced to enable the successful uptake and upscale of urban renaturing practices. Improving people’s understanding, perception, and emotions towards nature is therefore key. In this paper, we discuss how human knowledge and values of nature can be enabled through urban renaturing. Besides, we discuss the required transitions in urban planning processes to support urban renaturing practices.     

Influence of the Expert Effect on Cultural Models

We examined hunters’ perceptions of fauna to see if expert hunters and other hunters perceive wildlife abundance similarly. We used cultural consensus analysis (CCA) to assess the knowledge of 25 hunters in the Bolivian Amazon about the abundance of 38 animals. CCA indicated highly shared beliefs among hunters concerning wildlife abundance (average agreement = .62). However, expert hunters (as judged by their reported successful hunts of rare species, having hunted recently, and consuming more game in their diet) perceived more animals as abundant than did non-experts, although they all shared the same model. Since the expert hunters did not always agree on which species was more abundant, they had low cultural knowledge scores in CCA results. These experts may be unwilling to curtail hunting efforts on key species that they perceive to be abundant.     

基于CiteSpace的氮沉降知识图谱计量分析

客观分析国内氮沉降研究现状,总结现阶段研究的重点与薄弱点,旨在为氮沉降的科研工作者与决策者提供数据参考.以"氮沉降"为主题词,从CNKI数据库中得到2009-2019年发表的相关文献754篇,运用CiteSpace知识图谱分析工具对关键词、作者、机构进行可视化分析,并对氮沉降的研究进展、发展趋势和资助基金等方面进行相关...     

A Vovel Constracture of Combinatorial Knowledge Base for the Expert System of Eletrical Switching

By comparing the techniges of the production and the logic predicate for knowledge representation, this paper presents a kind of constructure of combinatorial knowledge base applied to the expert system for switch operation in electric power system . This constructure of knowledge base to be expanded and revised easily,and it is cinvenitnt to build the general shell of the expert system.