Farmers’ Risk‐Based Decision Making Under Pervasive Uncertainty: Cognitive Thresholds and Hazy Hedging

Researchers in judgment and decision making have long debunked the idea that we are economically rational optimizers. However, problematic assumptions of rationality remain common in studies of agricultural economics and climate change adaptation, especially those that involve quantitative models. Recent movement toward more complex agent‐based modeling provides an opportunity to reconsider the empirical basis for farmer decision making. Here, we reconceptualize farmer decision making from the ground up, using an in situ mental models approach to analyze weather and climate risk management. We assess how large‐scale commercial grain farmers in South Africa (n = 90) coordinate decisions about weather, climate variability, and climate change with those around other environmental, agronomic, economic, political, and personal risks that they manage every day. Contrary to common simplifying assumptions, we show that these farmers tend to satisfice rather than optimize as they face intractable and multifaceted uncertainty; they make imperfect use of limited information; they are differently averse to different risks; they make decisions on multiple time horizons; they are cautious in responding to changing conditions; and their diverse risk perceptions contribute to important differences in individual behaviors. We find that they use two important nonoptimizing strategies, which we call cognitive thresholds and hazy hedging, to make practical decisions under pervasive uncertainty. These strategies, evident in farmers' simultaneous use of conservation agriculture and livestock to manage weather risks, are the messy in situ performance of naturalistic decision‐making techniques. These results may inform continued research on such behavioral tendencies in narrower lab‐ and modeling‐based studies.     

供应链企业碳减排投资策略选择与行为演化研究

基于当下气候变暖的背景中有社会责任感的消费者对低碳产品有特殊偏好的情境,研究上游企业主导的供应链在面对具有低碳产品偏好的市场消费者时,上下游企业的减排投资行为与策略。依照Stackelberg博弈模型,构建上下游企业采用不同的行为策略的支付矩阵。进而,应用演化博弈理论中双种群演化博弈模型分析得到上下游企业减排投资行为的演化稳定策略:当需要较大的投资或者下游企业分担减排成本意愿较强时,由处于主导地位的上游企业实施投资减排是稳定的;当需要较小的减排投资或者下游企业分担减排成本意愿较弱时,上下游企业组成的供应链中必然会有一个企业实施减排。最后,指出了减排投资系数和下游企业分担投资成本比例的不同对演化博弈稳定均衡的影响。     

Evaluation of multi-objective optimization approaches for solving green supply chain design problems

This paper evaluates the applicability of different multi-objective optimization methods for environmentally conscious supply chain design. We analyze a case study with three objectives: costs, CO₂ and fine dust (also known as PM – Particulate Matters) emissions. We approximate the Pareto front using the weighted sum and epsilon constraint scalarization methods with pre-defined or adaptively selected parameters, two popular evolutionary algorithms, SPEA2 and NSGA-II, with different selection strategies, and their interactive counterparts that incorporate Decision Maker׳s (DM׳s) indirect preferences into the search process. Within this case study, the CO₂ emissions could be lowered significantly by accepting a marginal increase of costs over their global minimum. NSGA-II and SPEA2 enabled faster estimation of the Pareto front, but produced significantly worse solutions than the exact optimization methods. The interactive methods outperformed their a posteriori counterparts, and could discover solutions corresponding better to the DM preferences. In addition, by adjusting appropriately the elicitation interval and starting generation of the elicitation, the number of pairwise comparisons needed by the interactive evolutionary methods to construct a satisfactory solution could be decreased.     

基于产业集群的企业重点投资地区决策的仿真

用多Agent仿真技术,研究了基于产业集群的台资IT企业在大陆重点投资地区的决策问题。提出了针对这一问题的、将集群竞争力评价的GEM模型、多Agent仿真技术及演化博弈相结合的思路与方法。仿真模型对集群的研究方法以及多Agent的应用领域有拓展意义,而仿真发现与结论可为政府制定有关政策提供参考。     

零售市场价格策略的演化博弈分析

基于一个三阶段Hotelling博弈模型:位于[0,1]线性城市两端的零售A和B第一阶段同时选择价格策略变量,第二阶段确定价格的大小,第三阶段由消费者选择零售商。应用演化博弈论进行研究,分析了零售市场价格策略的演化稳定性。     

高校突发事件网络舆情传播的博弈分析--以香港占中事件为例

高校突发事件网络舆情的管理关系到高校教学乃至社会发展的稳定。以香港“占中”事件为例,运用演化博弈分析方法,建立学生群体面对突发事件策略选择的博弈模型,通过模型分析学生策略选择对网络舆情演变的影响。该模型可推广到一般的高校突发事件,对研究高校突发事件网络舆情具有一定的借鉴意义。     

BPR项目的实施:革命性变革和渐进性变革

进入变化时代后,如何应对变化是公司的每一位成员必须面对的现实。理论界一直争论的革命性变化和渐进性变化两种策略各有其长,各有优势。本文探讨了这两种变化策略的特点,比较了它们的异同之处,并且总结了几条如何正确应用革命性变化和渐进性变化这两种策略的规则,为企业正确实施变化管理提供一定的参考价值。     

On the Complexity of Constructing Evolutionary Trees

In this paper we study a few important tree optimization problems with applications to computational biology. These problems ask for trees that are consistent with an as large part of the given data as possible. We show that the maximum homeomorphic agreement subtree problem cannot be approximated within a factor of , where N is the input size, for any 0 in polynomial time unless P = NP, even if all the given trees are of height 2. On the other hand, we present an O(N log N)-time heuristic for the restriction of this problem to instances with O(1) trees of height O(1) yielding solutions within a constant factor of the optimum. We prove that the maximum inferred consensus tree problem is NP-complete, and provide a simple, fast heuristic for it yielding solutions within one third of the optimum. We also present a more specialized polynomial-time heuristic for the maximum inferred local consensus tree problem.     

环境保护的宏观经济成本分析

本文讨论了环境经济成本问题,提出环境治理成本和环境机会成本两组概念,并用投入占用产出方法研究了宏观经济环境机会成本核算。     

试论社会主义经济学的逻辑起点

分别以对最单纯的因素的分析、对历史的起点的分析、对系统的源泉的分析、对“包含着一切矛盾的胚芽”的“细胞”的分析为逻辑起点,是确定一门科学的逻辑起点的原则。社会主义实践表明,福利商品是社会主义经济的最单纯的因素,社会主义经济的历史从福利商品的产生开始,福利商品是社会主义经济系统的源泉,又是包含着社会主义一切矛盾胚芽的社会主义社会的“经济细胞”,因此,按照确定科学的逻辑起点的原则要求,“对福利商品进行分析”（或“分析福利商品”）就是社会主义经济学的逻辑起点