Institutional stakeholdings and better-informed traders at earnings announcements

Utama and Cready [Utama, S., Cready, W.M., 1997. Institutional ownership, differential predisclosure precision and trading volume at announcement dates. Journal of Accounting and Economics 24, 129–150] use total institutional ownership to proxy for the proportion of better-informed traders, an important determinant of trading around earnings announcements. We argue that institutions holding small stakes cannot justify the fixed cost of developing private predisclosure information. Also, institutions with large stakes generally do not trade around earnings announcements since they are dedicated investors or face regulations that make informed trading difficult. However, institutions holding medium stakes have incentives to develop private predisclosure information and trade on it; we show that their ownership is a finer proxy for the proportion of better-informed traders at earnings announcements.     

消费领域的量化自我:研究述评与展望

量化自我是指消费者对自我数据进行收集并经由数据获得自我知识的过程。量化自我能增强消费者的自我精准管控和行为理性,驱动消费者行为方式的转变。数据驱动的量化自我时代正在来临,全新的商业逻辑正在被建立起来。消费者的行为正从非标准化向精准化转变。鉴于此,越来越多学者开始围绕量化自我展开研究,在清晰界定量化自我概念的基础上,分析量化自我的参与动机与阶段性过程,关注量化自我带来的消费者精准化消费方式转变。本文系统回顾了量化自我相关研究,阐释了量化自我的概念与本质,从量化自我的类型与效用、动机与过程等方面对相关研究进行了述评,整理提炼了量化自我在消费领域的应用现状,并在此基础上明确了量化自我研究尚需解决的问题和未来的研究方向。     

Management by the Numbers: A Formal Approach to Deriving Informational and Distributional Properties of “Unmanaged” Earnings

We explore the theoretical relation between earnings and market returns as well as the properties of earnings frequency distributions under the assumption that managers use unbiased accounting information to sequentially decide on real options their firms have and report generated earnings truthfully, with the market pricing the firm based on those reported earnings. We generate benchmarks against which empirically observed earnings‐returns relations and aggregate earnings distributions can be evaluated. This parsimonious model shows a coherent set of results: reported losses are less persistent than reported gains, decision making diminishes the S‐shaped market response to earnings and earnings relate to returns asymmetrically in the way documented by Basu [1997]. Furthermore, the implied frequency distribution of aggregate earnings is neither symmetric nor necessarily single‐peaked. Instead, it may exhibit a kink at zero and look similar to the plots reported by Burgstahler and Dichev [1997]. However, within our model, none of these phenomena are due to reporting noise, bias, or some undesirable strategic managerial behavior. They are the natural consequences of using past earnings as the basis for value increasing managerial decision making that in turn generates the future earnings on which future decisions will be based.     

数控铣削螺纹的分析

数控铣削加工螺纹是应用数控系统三轴联动的典型示例。它不同与传统螺纹加工方法,有着高精度、高效率、高柔性等优点,因此应大力推广螺纹铣削加工编程技术。本文分析了用单刃螺纹刀来加工螺纹的方法。     

基于小波-BP神经网络的风电场短期风速预测

对风电场风速进行较准确预测可以调整调度计划,有效减轻风电对整个电网的不利影响。文章将小波技术和神经网络相结合对风速进行短期预测。先对原始风速数据进行小波分解,再针对各小波分量分别建立BP神经网络模型进行预测,最后通过小波重构得到原始风速预测值。仿真结果表明,所提方法能够有效地提高风速预测精度。     

Dynamic risk management in petroleum project investment based on a variable precision rough set model

In this paper, an adaptive algorithm is designed for dynamic risk management in petroleum project investment based on a variable precision rough set (VPRS) model. In risk management, at each stage of decision-making, experts are invited to identify risk indices and support the decision-maker in evaluating the risk exposure (RE) of individual projects. The VPRS model is used to mine risk rules and determine the significance of risk indices from RE decision tables. Considering that there are multiple risks involved in any petroleum project investment, we use multi-objective programming to obtain the optimal selection of projects with minimum RE, where the significance of risk indices is assigned to each of the corresponding multi-objective functions as a weight. Moreover, we develop a risk ranking model to measure the degree of risk for individual projects in a portfolio. Finally, a numerical example based on a Chinese petroleum company's investments in overseas projects is presented to illustrate the proposed approach, and then conclusions are drawn.     

无梭织机开口凸轮加工方法探讨

将数控加工技术和成组技术有机结合,应用于织机的开口凸轮加工,在有效降低加工成本、提高生产效率方面显示出极大的潜力.在多品种、小批量产品的加工中,有显著的优势.     

关于高精度轨道绝对坐标测量系统应用的探讨

保证高速列车运营安全和舒适性的首要条件是轨道的高平顺性,轨道的高平顺性依赖于高质量的轨道铺设和养护维修,而获得高质量轨道几何线形的基础是精密的测量技术,因此,高速有砟轨道建立高精度轨道绝对坐标测量系统,不仅是施工的需要,也是今后线路养护维修工作的基础和保证。建立高精度轨道绝对坐标测量系统在国内具有其先进性和创新性,并具有极高的应有价值,对指导时速200～250km有砟轨道养护、维修、施工是适宜的,便于操作和实施,具有较高的经济、社会效益。     

基于ADS1248高精度测温装置的设计

针对疫苗的运送及仓储过程中对环境温度的严格要求,设计了高精度的测温装置。选用了Pt100作为温度传感器,采用四线制测量方法去除了传输线上的干扰,设计了比例测量法使系统的精度仅依赖于一个高精度电阻。选用的ADS1248芯片内部包含了PGA放大器及24位ADC芯片,降低了装置的复杂性,同时具有较高的分辨率。经测试,本装置的测温精确达到0.1℃,能够满足疫苗的运送及仓储的要求。     

基于周期的低轨预警系统任务动态重规划策略

根据预警系统资源的特点和导弹跟踪任务的实时性和不确定性,天基低轨预警系统 任务规划具有动态性的特点。为解决低轨系统动态任务规划问题,提出了低轨预警系统动态 任务规划模式,分析了周期重规划调度策略,探讨了系统动态重规划中重规划周期的确 定方法,并对其中的弹道预测误差椭球和双星定位精度两个关键问题进行了建模,为动态问 题建模求解提供基础。