时间的“形而下”之维： 论现代法律中的时间要素

时间成为法律规范的必备要素,体现了法律与时间关系变化的趋势。比较来看,传统法律呈现出传统社会时间观的鲜明特征,其表达具有明显的自然性,立法水平也较低;现代法律中的时间则是一个更具客观性的概念,且包含着一整套关于时间的规则。根源上,时间嵌入法律肇始于现代化： 一方面,现代化指向与传统截然不同的时间观念与制度,形成了“技术—观念—制度”这一具有传导性的动力机制,为时间嵌入法律提供了主客观条件;另一方面,现代化对法律提出了全新要求,时间作为法律规范要素因之体现在三个维度,即作为权利要件的法律时间、作为行为准则的法律时间和作为惩罚手段的法律时间。     

基于时间序列极值理论的跳跃风险研究

金融资产的跳跃行为作为对极端事件的刻画,为研究极端事件风险提供了良好工具。基于时间序列下的极值理论,在放松独立同分布假设下,构造了金融资产收益率序列尾部中跳跃动态特征的极值模型。通过对上证综指大跨度、高频度的实证研究,剖析了投资者结构、投资者行为与收益尾部分布之间的相互作用机制,进一步对金融资产收益尾部的跳跃风险进行了有效测度。结果表明,极端跳跃风险的分布特征在频率与尾部方向上呈现很强的不对称状态。     

时间约束下的组织间知识转移粘滞形成机理研究

随着知识经济时代的到来,有关知识转移的研究也在不断深入,而降粘技术的研究则成为其中的重点。笔者在文献回顾的基础上,提出了时间维度是知识转移粘滞重要影响因素的观点,并建立了完善的知识转移粘滞影响因素概念模型,从时间维度对知识转移粘滞的影响因素进行了分析。     

Organic certification,export market access and the impacts of policy: Bayesian estimation of avocado smallholder “times‐to‐organic certification” in Michoacán Mexico

This study analyzes organic adoption decisions using a rich set of time‐to‐organic durations collected from avocado small‐holders in Michoacán Mexico. We derive robust, intrasample predictions about the profiles of entry and exit within the conventional‐versus‐organic complex and we explore the sensitivity of these predictions to choice of functional form. The dynamic nature of the sample allows us to make retrospective predictions and we establish, precisely, the profile of organic entry had the respondents been availed optimal amounts of adoption‐restraining resources. A fundamental problem in the dynamic adoption literature, hitherto unrecognized, is discussed and consequent extensions are suggested.     

Are entrepreneurs influenced by risk attitude,regulatory focus or both? An experiment on entrepreneurs' time allocation

“Hybrid entrepreneurs” — those who maintain a wage job while starting a new enterprise — outnumber pure entrepreneurs in many countries. Yet, how hybrid entrepreneurs allocate their working hours between these two activities is not well understood. To better understand the relationship between hybrid entrepreneurs' division of time between their wage jobs and new enterprises we develop a model that captures hybrid entrepreneurs' decisions on the tradeoffs between financial risk and return as it relates to time allocation. We test two hypotheses based on utility theory, and challenge them with two hypotheses based on regulatory focus theory in a controlled experiment with 25 early stage entrepreneurs and 29 undergraduate students. In the computer-based experiment, entrepreneurs' and students' time allocation decisions (tied to monetary incentives) are used to test what would motivate them to work more or less hours in their entrepreneurial startups. We find that the actual time allocation decisions of the student group are somewhat in tune with utility theory, but that the entrepreneurs' time allocation decisions are better explained by regulatory focus theory.     

Forecasting the New York State economy: The coincident and leading indicators approach

Currently there are no reliable summary indicators of the economic and fiscal condition of states and localities. This deficiency has hampered the efforts of policy makers at the sub-national level to monitor changes in the economic environment and predict how those changes will impact the fiscal health of governments. This paper attempts to fill this analytical vacuum by providing summary indicators of economic and fiscal health for New York State. The models developed are based on the single-index methodology developed by Stock and Watson [(1991). A probability model of the coincident economic indicators. In K. Lahiri and G. H. Moore (eds.), Leading economic indicators: new approaches and forecasting records (pp. 63–85). New York: Cambridge University Press]. This approach allows us to date New York business cycles and compare local cyclical behavior with the nation as a whole. We develop a leading index of economic indicators which predicts future movements in the coincident indicator. The Stock and Watson approach is used to create a fiscal indicator which acts as a summary indicator of revenue performance for New York. In addition, we explore the ability of our economic indicator series to predict future changes in state revenues. We find that changes in the leading indicator series have significant predictive power in forecasting changes in our revenue index.     

Short-term forecasting of crime

The major question investigated is whether it is possible to accurately forecast selected crimes 1 month ahead in small areas, such as police precincts. In a case study of Pittsburgh, PA, we contrast the forecast accuracy of univariate time series models with naïve methods commonly used by police. A major result, expected for the small-scale data of this problem, is that average crime count by precinct is the major determinant of forecast accuracy. A fixed-effects regression model of absolute percent forecast error shows that such counts need to be on the order of 30 or more to achieve accuracy of 20% absolute forecast error or less. A second major result is that practically any model-based forecasting approach is vastly more accurate than current police practices. Holt exponential smoothing with monthly seasonality estimated using city-wide data is the most accurate forecast model for precinct-level crime series.     

The Effect of Accountability and Time Budgets on Auditors' Testing Strategies*

This study investigates the joint effects of accountability and time budgets on auditors' testing strategies. The task studied, substantive analytical procedures, requires auditors to identify and test hypotheses when investigating the cause of unexpected fluctuations. Thus, auditors must determine the number of tests to conduct (i.e., extent), the number of potential hypotheses to directly test (i.e., breadth), the number of tests for each hypothesis (i.e., depth) and the number of potential error or non‐error hypotheses to test (i.e., focus). Testing strategies, which we define as choices made with respect to extent, focus, depth, and breadth of testing, have significant practical and theoretical implications. For example, reducing the breadth of testing may result in failure to test the correct hypothesis, potentially impairing audit effectiveness. In this study, auditors inherited five potential causes of an unexpected increase in the gross margin of a client. As in practice, their task was to conduct tests to investigate and identify the actual cause of the fluctuation. Auditors were randomly assigned to one of four conditions created by fully crossing accountability and time budgets. The results indicate that accountability leads to an increase in the extent and breadth of testing but does not affect the depth of testing. Further, accountability leads to an increase in the testing of errors but results in a decrease in the testing of non‐errors. The focus on breadth and error testing is consistent with the notion that accountability, to a superior with unspecified preferences, promotes more cautious behavior. The results also show that a time budget decreases the extent and depth of testing but does not affect the breadth of testing. There was no evidence that the two factors interactively affected testing strategies or performance. Finally, increased breadth of testing was the mechanism that led to better performance as measured by the identification of the actual cause of the unexpected fluctuation.     

测控系统测轨数据的时间校正问题

本文分析了航天测控系统几类测轨数据的时间校正问题及相应的校正计算方法,指出在同一系统时标形成的测轨数据不一定是同一时的目标参数,提出了使各测轨数据同步的一种方案.     

Endogenous time preference and optimal growth

We adapt the classic one-sector optimal growth model to include an endogenous rate of time preference along the lines of Becker and Mulligan (1997). The resulting model is both time-consistent and analytically tractable. Capital sequences are shown to be globally monotone and stable under very general circumstances using lattice programming techniques and value orders. We analyze a series of examples that exhibit a variety of behaviors, including closed-form solutions, unique steady-states, multiple steady-states, and conditionally sustained growth. The endogenous rate of discount preserves monotonicity and stability while allowing for the possibility of non-global convergence.I would like to thank Robert Becker, Leonard Mirman, Michael Kaganovich, Itzhak Zilcha, and an anonymous referee for helpful comments and discussions.