The Zilcha criteria for dynamic inefficiency reconsidered

We reconsider necessary and sufficient conditions for dynamic inefficiency given in Zilcha (J Econ Theory 52:364–379, 1990, J Econ Theory 55:1–16, 1991) and a critique by Rangazas and Russell (2005). First, we show that the characterization given in Zilcha (1990) for nonstationary economies is correct and correct Zilcha’s proof. Second, using this insight, we complement Rangazas and Russell’s (Econ Theory 26:701–716, 2005) discussion of the counterexamples to Zilcha (J Econ Theory 55:1–16, 1991). Third, we discuss consequences of our results for applied tests of (in-)efficiency based on the Zilcha criteria. We would like to thank Itzhak Zilcha, and in particular Peter Rangazas and Steve Russell for detailed and very helpful comments.     

The ‘inventor balance’ and the functional specialization in global inventive activities

Inventors and organizational assets are inputs of inventive activities which are often provided at a global scale, where countries might specialize in the provision of one or the other type of inputs. We introduce a new patent-based metric, the ‘inventor balance’, to quantify this type of functional specialization, which we discover to be considerable, and we propose a conceptual framework to explain it. We observe a progressive ‘decoupling’ of national sub-systems providing respectively inventors and organizational assets. Moreover, we find that countries with a high level of innovativeness relative to their economic development, high technological specialization, and strong individualistic cultural traits, contribute relatively more inventors than organizations to the global production of inventions.     

Small‐cost asymptotics for long‐term growth rates in incomplete markets

This paper provides a rigorous asymptotic analysis of long‐term growth rates under both proportional and Morton–Pliska transaction costs. We consider a general incomplete financial market with an unspanned Markov factor process that includes the Heston stochastic volatility model and the Kim–Omberg stochastic excess return model as special cases. Using a dynamic programming approach, we determine the leading‐order expansions of long‐term growth rates and explicitly construct strategies that are optimal at the leading order. We further analyze the asymptotic performance of Morton–Pliska strategies in settings with proportional transaction costs. We find that the performance of the optimal Morton–Pliska strategy is the same as that of the optimal one with costs increased by a factor of . Finally, we demonstrate that our strategies are in fact pathwise optimal, in the sense that they maximize the long‐run growth rate path by path.     

利用累积量和似然特征的卫星单-混信号调制识别算

针对卫星通信中常用调制信号和PCMA类混叠信号的调制识别问题,提出了一种利用 高阶累积量和似然特征的识别算法。算法先对接收数据进行预处理,在此基础上提取4个高 阶累积量特征和1个似然特征,构造一个树形分类器进行调制识别。算法不需要知晓信号的 定时等先验信息,对收发载频存在的频差不敏感。仿真结果表明,算法在正常通信所需的载 噪比下具有较高的正确识别率。     

城市群规划的视角与规范性研究

城市群发育的阶段性与层次性、节点网络的结构性及其稳定性、区域发展的联系性及联系的动态性、节点的等级性及节点间的通达性4个特征分别阐述了其在城市群规划中的意义,并以此确定城市群规划的内容,即空间组织、产业、基础设施、生态建设和空间管治;规划的形式分为背景与目标、战略内容和实施保障。     

ASTM国际比对试验操作流程

随着分析测试行业的日渐放开,境外检验机构纷纷涌入,加之国内实验室评级标准的不断提高,内部、外部环境都对实验室的生存与发展提出了更高的要求.除了实验室的硬件和软件配置外,所出数据的准确性也是评判实验室的重要标准之一,实验室能力验证无疑是保证测试数据准确性的有效手段.由于国际间各实验室从实验仪器、人员构成、技术水平到外部自然条件等都存在较大的差异,所以参与这样的国际间比对试验可以放大实验室内部存在的系统误差,有助于及时发现问题,从而纠正、改进.本文介绍了参与ASTM国际比对试验,从申请注册到数据提交的全部程序,希望本文对寻求国际间比对试验项目的实验室有所裨益.     

高职院校高等数学师资队伍评价标准研究

高等数学在职业教育的人才培养过程中,发挥着重要的作用。然而在职业教育不断发展的过程中,也有一些值得关注的问题。即在师资队伍评价方面,目前还没有一个有效的、易操作的师资队伍评价标准。本文结合工作实践,研究了高职教育师资队伍评价标准。     

Subtle price discrimination and surplus extraction under uncertainty

This paper provides a solution to Proebsting’s Paradox, an argument that appears to show that the investment rule known as the Kelly criterion can lead a decision maker to invest a higher fraction of his wealth the more unfavorable the odds he faces are and, as a consequence, risk an arbitrarily high proportion of his wealth on the outcome of a single event. The paper shows that a large class of investment criteria, including ‘fractional Kelly’, also suffer from the same shortcoming and adapts ideas from the literature on price discrimination and surplus extraction to explain why this is so. The paper also presents a new criterion, dubbed the doubly conservative criterion, that is immune to the problem identified above. Immunity stems from the investor’s attitudes toward capital preservation and from him becoming rapidly pessimistic about his chances of winning the better odds he is offered.     

What is macroeconomic causality?

The paper aims to develop an adequate account of macroeconomic causality. It discusses the definition that is central to Woodward’s interventionist account and the definitions that can be extracted from Hoover’s remarks on privileged parameterization and from the potential outcome approach that Angrist and Kuersteiner have introduced into macroeconomics more recently. The definition to be defended can be regarded as the gist that is common to all three definitions when they are relieved of overly restrictive conditions. It says (roughly) that X causes Y if and only if there is a possible intervention on X that changes Y, where X and Y stand for macroeconomic aggregates, where an intervention is understood as a manipulation of an intervention variable I that satisfies conditions requiring that I be a cause of X, and that there be no confounders of X and Y, and where an intervention variable is either a variable or a parameter.     

Alpha-robust mean-variance reinsurance-investment strategy

Inspired by the α-maxmin expected utility, we propose a new class of mean-variance criterion, called α-maxmin mean-variance criterion, and apply it to the reinsurance-investment problem. Our model allows the insurer to have different levels of ambiguity aversion (rather than only consider the extremely ambiguity-averse attitude as in the literature). The insurer can purchase proportional reinsurance and also invest the surplus in a financial market consisting of a risk-free asset and a risky asset, whose dynamics is correlated with the insurance surplus. Closed-form equilibrium reinsurance-investment strategy is derived by solving the extended Hamilton–Jacobi–Bellman equation. Our results show that the equilibrium reinsurance strategy is always more conservative if the insurer is more ambiguity-averse. When the dependence between insurance and financial risks are weak, the equilibrium investment strategy is also more conservative if the insurer is more ambiguity-averse. However, in order to diversify the portfolio, a more ambiguity-averse insurer may adopt a more aggressive investment strategy if the insurance market is very ambiguous. For an ambiguity-neutral insurer, the investment strategy is identical to the non-robust investment strategy.