城市化发展中的人口与经济增长

基于非线性理论,针对人口增长和经济发展中的非线性现象,根据城市化发展中的人口和经济这两个主要因子的制约关系,建立了人口-经济模型,并对其进行了运动稳定性和动力学特性的分析。人口-经济模型的建立,可为城市化发展中的人口与经济增长问题提供定量分析的依据。     

Statistical mechanical analysis of the dynamics of learning in perceptrons

We describe the application of tools from statistical mechanics to analyse the dynamics of various classes of supervised learning rules in perceptrons. The character of this paper is mostly that of a cross between a biased non-encyclopaedic review and lecture notes: we try to present a coherent and self-contained picture of the basics of this field, to explain the ideas and tricks, to show how the predictions of the theory compare with (simulation) experiments, and to bring together scattered results. Technical details are given explicitly in an appendix. In order to avoid distraction we concentrate the references in a final section. In addition this paper contains some new results: (i) explicit solutions of the macroscopic equations that describe the error evolution for on-line and batch learning rules; (ii) an analysis of the dynamics of arbitrary macroscopic observables (for complete and incomplete training sets), leading to a general Fokker–Planck equation; and (iii) the macroscopic laws describing batch learning with complete training sets. We close the paper with a preliminary expose´ of ongoing research on the dynamics of learning for the case where the training set is incomplete (i.e. where the number of examples scales linearly with the network size).     

联立方程计量经济学模型的结构识别

本文提出了联立方程计量经济学模型结构识别的概念与方法。应用该方法识别模型与统计数据无关,并且与模型参数的具体数值也无关,对计量经济学建模与分析有实际意义.     

Coming of age

Those of us who study aging have the unique opportunity to live their subject matter. Whether we learn any personal lessons is a matter of our own reflectivity, but personal experience can make us far better scholars than can scholarship alone. As one ponders the life course, it is clear that a number of institutional influences, temporal patterning, and unexpected intervening variables are involved in the unfolding of one's life. Life-long institutional memberships furnish social capital that helps establish parameters for our personal experience, for how we view our personal trajectories and for our ability to cope with the aging process itself. But how to come to terms with unexpected occurrences that alter the anticipated futures we had in mind? Do our scholarly efforts and our experience come together in ways that enrich one or the other? These are the questions I explore in this personal essay.     

全球化世界中的农村生计:重回阶级视角审视

文章认为，在现代全球化商品生产环境下，构建生产和再生产的社会关系从普遍意义上讲就是阶级关系，提出应重回阶级视角审视和分析农村贫困及其产生原因。在这一视角下对现代农地变迁进行探讨，并在提出当代农耕变化七个命题的基础上，识别了不同阶层关系下的动力机制和不同发展政策议题下隐含的阶级动力，并指出，现有关于改善农业生产、农村生计和福利的政策忽略了阶级不平等性，因此它们也忽略了贫困的根本社会基础以及不同干预对此带来的重要影响。     

robability is obtained as the va

algebraic equation that depends on the cumulant generating function (CGF) of the performance variable. A method for calculating the saddlepoint using random samples of the performance variab     

和谐社会政治发展的动力机制和平衡机制（上）

和谐社会政治发展的运行机制主要包含动力机制和平衡机制。建立和健全适应和谐社会政治发展的动力机制,主要应从建设强有力的执政党和政府(政治发展的牵引力)、建设充满活力的国家政治体系(政治发展的内驱力)、建设自主自治的公民社会(政治发展的推动力)等方面入手;建立和健全适应和谐社会政治发展的平衡机制,应该努力实现政治价值性平衡(公平正义)、政治制度性平衡(权力制衡)、政治过程性平衡(协调有序)。     

碳强度对中国主要产业部门产值变动敏感性的动态估计

测算产业产值变动对碳强度的作用,可以为碳减排目标下产业结构调整方案的制定提供指导。基于投入产出理论建立系统动力学模型,以此为基础,分析中国主要产业部门产值变动对碳强度的动态作用过程,并从投资结构和消费结构两个方面探讨实现中国主要产业部门碳减排目标的有效途径。研究结果表明:从即期效应来看,制造业,电力、热力及水的生产和供应业,采矿业,其产值增加会使碳强度提高;从动态变化过程来看,农林牧渔业,采矿业,制造业,建筑业,交通运输、仓储和邮电业,批发零售贸易、住宿和餐饮业,房地产、租赁和商务服务业,其产值增加1%后碳强度呈现逐年降低的趋势;从碳强度的变化趋势来看,各产业部门产值增加对碳强度的作用力逐渐趋于稳定;产业产值变动碳减排效力的提高要依靠投资政策。     

我国公立医院补偿机制转化的系统动力学分析

取消药品加成,改革以药补医机制是公立医院补偿机制改革的核心内容。文章运用系统动力学方法,通过因果关系分析明确取消药品加成后,财政补偿和医疗补偿的补偿方式和补偿依据,以及补偿不足、药品路径存在漏洞时可能会对公立医院产生的影响,最后给出结论与启示。     

The Impact of Competitive Strategy and Supply Chain Strategy on Business Performance: The Role of Environmental Uncertainty*

This article investigates the relationships among competitive strategy, supply chain strategy, and business performance while examining the moderating effect of environmental uncertainty. A total of 604 questionnaires were collected from three cities in China, and the statistical results show significant moderating effects of external environment on the relationships among competitive strategy, supply chain strategy, and business performance. Firms that primarily focus on a differentiation strategy emphasize an agile supply chain strategy. Cost leaders are inclined to implement both lean and agile supply chain strategies, but their emphasis on agile strategy is significantly greater in a volatile environment than in a stable environment. The choice of supply chain strategy does not appear to be an “either‐or” decision and firms could adopt either a lean or an agile strategy, or both, depending on the environment. This article provides significant managerial implications for supply chain practitioners to co‐align supply chain strategy and competitive strategy with the environment to improve performance.