运筹帷幄的决策工具——运筹学

运筹学是关于做决定的科学,运筹学集数学和其他科学方法为一体,对现实问题进行模型化并提出解决方案,把它科学地应用到各企业管理中,可有效地帮助企业做出合理的决策.     

Challenges in developing and implementing a decision support systems (ETÇAP) in forest management planning: a case study in Honaz and Ibradı, Turkey

Decision support systems (DSSs) are indispensable tools in preparing a forest management plan for a better combination of multiple forest values. This study attempted to develop and explain a stand-based forest management DSS (Ecosystem-based multiple-use forest planning [ETÇAP]) comprising a traditional simulation, linear programming (LP), metaheuristics and geographic information system. The model consists of five submodels; traditional management approach to handle inventory data, an empirical growth and yield model, a simulation to conceptualize management actions, a LP technique to optimize resource allocation and a simulated annealing approach to directly create a spatially feasible harvest schedule. The ETÇAP model has been implemented in a comparative two case study areas; Denizli–Honaz and Akseki–Ibrad?. Both simulation and optimization models outperformed to the traditional management plan. The periodical change of growing stock, allowable cuts, carbon sequestration and water production are used as performance indicators. The results showed that more amount of wood could be harvested over time compared to traditional level of harvesting. It could be concluded that various management strategies allowed managers to stimulate more decision options for better outputs through intertemporal trade-offs of management interventions as the model provided tools to quantify forest dynamics over time and space. Challenges exist to establish the functional relationships between forest structure and values for better quantification and integration into the management plans.     

冀、鲁、豫、苏、皖五省农机夏收跨区作业调研报告

农机跨区作业是我国农民自发进行的又一项伟大的制度创新,为促进我国农业机械化发展做出了重要的贡献.为此,采用问卷调查法、文献资料法和数理统计法,对冀、鲁、豫、苏、皖等省505户参与跨区作业的农机大户进行了问卷调查.以问卷数据为基础,分析了农机大户的自身特征和经营状况,并总结了影响跨农机大户参与跨区作业的主要因素,最后提出了相应的对策建议.     

基于文献计量分析的国内外农业规模经营研究热点演化与新兴趋势分析

为梳理总结国内外农业规模经营的总体概况、研究热点和未来发展趋势,以Web of Science核心合集和中国知网CSSCI数据库文献为研究对象,综合运用HistCite和VOSviewer文献计量软件对年度发文量、高被引作者、引文编年图以及热点关键词等进行可视化分析。结果表明：1）国内外农业规模经营年度发文量呈现波动上升态势,且发文集中于国内外权威期刊上。2）国际农业规模经营研究主题丰富,相互之间印证密切,学界研究重点从早期的经济效益逐渐转型到社会和生态效益,主要包括农业生产力、贫困、健康营养、食品安全、气候变化和资源环境等研究方向。3）国内农业规模经营研究虽起步较晚,但鉴于中国特殊国情农情,研究主题更为细化,主要包括粮食安全、农民增收、面源污染、产权制度改革、全要素生产率以及农业社会化服务等研究方向。另外,受国际思潮的影响,中国农业规模经营研究也逐步向气候变化和营养均衡等方面转变。综上,未来中国还需要从农业规模经营基础理论体系构建和研究方法创新、新兴研究方向探索以及加强国际交流合作等方面深化研究。     

岩土工程勘察作业的重要性与方法

重视岩土工程勘察作业,把握技术分析中的每一环节,强调事先指导、过程控制、事后总结。对于提高岩土工程师的专业技术水平,保证岩土工程勘察质量,促进建设工程的顺利开展,能起到事半功倍的效果。基于岩土工程勘察工作的重要性,从实际的工作经验出发,就勘察前期、中期和后期如何做好岩土工程勘察的外业工作进行了深入探讨,并提出了具体的建议。     

Different responses in bulk density and saturated hydraulic conductivity to soil deformation by logging machinery on a Ferralsol under native forest

Ferralsols have high structural stability, although structural degradation has been observed to result from forest to tillage or pasture conversion. An experimental series of forest skidder passes in an east Amazonian natural forest was performed for testing the effects of mechanical stress during selective logging operations on a clay‐rich Ferralsol under both dry and wet soil conditions. Distinct ruts formed up to 25 cm depth only under wet conditions. After nine passes the initially very low surface bulk density of between 0.69 and 0.80 g cm^?3 increased to 1.05 g cm^?3 in the wet soil and 0.92 g cm^?3 in the dry soil. Saturated hydraulic conductivities, initially >250 mm h^?1, declined to a minimum of around 10 mm h^?1 in the wet soil after the first pass, and in the dry soil more gradually after nine passes. The contrasting response of bulk density and saturated hydraulic conductivity is explained by exposure of subsoil material at the base of the ruts where macrostructure rapidly deteriorated under wet conditions. We attribute the resultant moderately high hydraulic conductivities to the formation of stable microaggregates with fine sand to coarse silt textures. We conclude that the topsoil macrostructure of Ferralsols is subject to similar deterioration to that of Luvisols in temperate zones. The stable microstructure prevents marked compaction and decrease in hydraulic conductivity under wetter and more plastic soil conditions. However, typical tropical storms may regularly exceed the infiltration capacity of the deformed soils. In the deeper ruts water may concentrate and cause surface run‐off, even in gently sloping areas. To avoid soil erosion, logging operations in sloping areas should therefore be restricted to dry soil conditions when rut formation is minimal.     

对标三个面向试验基地支撑创新工程实施

以中国农业科学院南口、廊坊基地为例,对标“三个面向”总体目标,从统筹利用资源,优化管理队伍,稳定运行经费,拓展基地功能等方面,文章提出运行管理工作建议,推动南口、廊坊基地提供高质量保障服务,支撑创新工程实施。     

汽车运用工程新标准和应用

本文汇集了我国近年来新发布的关于汽车运用工程国家或行业标准，对这些标准进行了特点分析和应用研究。     

基于灰色关联分析的区域保险差异影响因素分析

研究了经济学中广泛应用的决策模糊理论中模糊集覆盖系数的性质，并据此提出了无须通过繁杂的统计实验就能够计算覆盖系数的实用方法，进而提出了模糊集交并运算算子. 用两个算例说明了该方法和算子与实际情形相符，具有可行性.     

基于Matlab的AHP分析程序设计

层次分析法是目前最为广泛应用的决策方法,但涉及大量的矩阵运算,影响了该方法的推广。Matlab软件精于矩阵运算,与C语言结构类似,移植性强,本研究基于Matlab设计出了便捷高效的AHP计算机程序。