Maximising sustainability of Dutch dairy farming systems for different stakeholders: A modelling approach

A multi-attribute sustainability function is included into a dairy farm LP-model by using Weighted Goal Programming. The created Weighted Linear Goal Programming (WLGP)-model is used to maximise sustainability of different Dutch dairy farming systems and to analyse the impact of: (1) maximisation of individual sustainability aspects (economic, social and ecological sustainability) and (2) maximisation of overall sustainability using stakeholder preferences. Maximising the individual aspects of both dairy farming systems, i.e. conventional and organic, shows the trade-offs between different aspects of sustainability. For conventional as well as organic dairy farming maximum scores are highest for external social sustainability. The conventional dairy farm achieves a slightly higher score for overall sustainability than the organic dairy farm for all stakeholders (i.e. consumers and producers). This shows that it is possible for conventional dairy farms, similar to the conventional farm used in the analysis especially regarding the stocking density and under Dutch policy conditions, to achieve equal sustainability scores in comparison with organic dairy farms. It is concluded that the WLGP model is a suitable tool to analyse the sustainability of different dairy farming systems.     

《C语言程序设计》课程的教改探索

高职高专的《C语言程序设计》课程可根据专科学生的特点和自身的培养目标,从师资建设、课堂教学、实践环节、课程作业、教学资源建设、教学评价、教学管理等几个方面进行。这些改革效果不仅能使学生较好地掌握课程的核心内容,而且可以激发学生继续探索和学习的创新潜能。     

基于案例教学法的教学实践与研究

《C语言程序设计》具有理论性和实践性强的特点,如何将问题的解决算法转化为程序设计语言,成为学生学习《C语言程序设计》的瓶颈问题。通过分析《C语言程序设计》教学中存在的不足之处和案例教学法的优势所在,结合自己的教学实践,在日常教学中运用案例教学法,并对相关问题进行了探讨。     

一种改进的不完全指数复制方法

本文在考虑交易成本和投资组合动态调整的基础上,建立混合整数线性规划模型,引入内核搜索分析框架进行近似求解,并利用沪深300进行实证研究。研究发现,一是相比于基本内核搜索法,增强型内核搜索法仅在基准指数成分股数量很大时才会较大幅度提高求解质量;二是考虑投资组合动态调整的模型不仅更稳健,而且跟踪的继承性和保持性更好,尤其适用于单边市场;三是过度刻画现实交易特征一定程度上会降低不完全指数复制模型的复制和预测效果。     

Excel规划求解工具在多目标规划中的应用

多目标决策方法是从20世纪70年代中期发展起来的一种决策分析方法。该方法已广泛应用于人口、环境、教育、能源、交通、经济管理等多个领域。文章采用多目标决策方法中分层序列法的思想,应用Excel的规划求解工具,对多目标规划问题进行应用研究,并以实例加以说明。     

The effects of tariffs on coalition formation in a dynamic global warming game

The prospects for cooperation on climate protection beyond 2012 are currently uncertain. Thus policy instruments which foster participation in International Environmental Agreements (IEA) are in demand. Among the instruments under discussion are trade sanctions. Multi-region optimal growth models are a state of the art tool for integrated assessment, but introducing trade sanctions distorts the competitive equilibrium, making it difficult to compute numerically. We introduce trade and trade sanctions into a model of coalition stability to assess the potential of trade sanctions to support an IEA. Trade is modeled by having all countries produce a generic output good, but adopting national product differentiation (Armington assumption). Coalitions are free to impose tariffs on imports from non-cooperating countries. We solve the model numerically using a refined version of Negishi's [Negishi, T., 1960. Welfare economics and existence of an equilibrium for a competitive economy. Metroeconomica 12, 92–97] basic algorithm. We then apply the model to analyze the influence of tariffs on international cooperation. The model suggests that there is indeed a significant potential to raise participation through trade sanctions, even when goods from different countries are nearly perfect substitutes. Furthermore we investigate the effect of trade sanctions on global welfare, environmental effectiveness, and the credibility of the tariff mechanism.     

基于时段偏好的高速铁路列车停站方案双层规划方法

旅客出行需求不断提高,需要同时考虑旅客出行时段选择与运输企业效益,来优化调整高速铁路列车停站方案。针对一条拥挤的高速铁路客运走廊,分时段确定列车停站计划和开行频率,阐述影响旅客出行时段偏好的2个重要因素——吸引度与可达度,据此构建旅客出行阻抗函数,构建双层规划模型,上层规划是以运营成本最小为目标的整数规划模型,用于确定列车停站方案;下层规划是一个用户平衡模型,用于计算客流在停站方案上的分配结果。根据模型特点设计启发式算法,并通过算例对模型和算法进行验证和分析。研究表明,考虑旅客出行时段偏好优化高速铁路列车停站方案的方法,能更好地匹配旅客需求分布,为旅客提供优质服务。     

FORTRAN语言及汇编语言在坐标测量中的混合编程技术

本文论述了Fortran在坐标测量数据采集系统以及图形输出系统中与汇编语言的程序连接及调用方法,讨论了利用Fortran语言进行测量样本点的拟合、画线以及图形输出问题,给出了编程方法及实例。