Forecast combining with neural networks

This paper investigates the use of Artificial Neural Networks (ANNs) to combine time series forecasts of stock market volatility from the USA, Canada, Japan and the UK. We demonstrate that combining with nonlinear ANNs generally produces forecasts which, on the basis of out-of-sample forecast encompassing tests and mean squared error comparisons, routinely dominate forecasts from traditional linear combining procedures. Superiority of the ANN arises because of its flexibility to account for potentially complex nonlinear relationships not easily captured by traditional linear models.     

How efficient is the European football betting market? Evidence from arbitrage and trading strategies

This paper assesses the international efficiency of the European football betting market by examining the forecastability of match outcomes on the basis of the information contained in different sets of online and fixed odds quoted by six major bookmakers. The paper also investigates the profitability of strategies based on: combined betting, simple heuristic rules, regression models and prediction encompassing. The empirical results show that combined betting across different bookmakers can lead to limited but highly profitable arbitrage opportunities. Simple trading rules and betting strategies based on forecast encompassing are found capable of also producing significant positive returns. Despite the deregulation, globalization and increased competition in the betting industry over recent years, the predictabilities and profits reported in this paper are not fully consistent with weak-form market efficiency. Copyright © 2008 John Wiley & Sons, Ltd.     

How probable is probable? A numerical translation of verbal probability expressions

The reported experiment took place in a professional forecasting organization accustomed to giving verbal probability assessments (‘likely’, ‘probable’, etc.). It attempts to highlight the communication problems caused by verbal probability expressions and to offer possible solutions that are compatible with the forecasters overall perspective on their jobs Experts in the organization were first asked to give a numerical translation to 30 different verbal probability expressions most of which were taken from the organization's own published political forecasts. In a second part of the experiment the experts were given 15 paragraphs selected from the organization's political publications each of which contained at least one verbal expression of probability. Subjects were again asked to give a numerical translation to each verbal probability expression The results indicate that (a) there is a high variability in the interpretation of verbal probability expressions and (b) the variability is even higher in context. Possible reasons for the context effect are discussed and practical implications are suggested.     

A loose and separate certainty: Caves, Fuchs and Schack on quantum probability one

Carlton Caves, Fuchs, and Schack (2002) have recently appealed to an argument of mine (Stairs, 1983) to address a problem for their subjective Bayesian account of quantum probability. The difficulty is that on the face of it, quantum mechanical probabilities of one appear to be objective, but in that case, the Born Rule would yield a continuum of probabilities between zero and one. If so, we end up with objective probabilities strictly between zero and one. The authors claim that objective probabilities of one leads to a dilemma: give up locality or fall into contradiction. I argue that this conclusion depends on an overly strong interpretation of objectivism about quantum probabilities.     

基于图像式行驶记录仪的汽车-自行车交通冲突特性研究

汽车与自行车事故在我国交通事故总数中占有重要比例。为了研究汽车与自行车交通冲突／事故特性,本文选用50辆出租车,利用图像式汽车行驶记录仪在北京市开展了为期一年的交通冲突调查,从冲突类型、冲突时间、冲突地点及交通控制方式、冲突车速及交通流、驾驶员视线遮挡等方面综合分析汽车一自行车冲突特性,研究结果对道路交通安全管理、道路设计及事故预防技术具有重要的意义。     

工作家庭冲突对生活满意感的影响：个人应对策略的调节作用

近年来,工作家庭冲突是组织行为学领域的研究重点。已有研究表明,这类因员工无法同时兼顾工作角色和家庭角色要。求而产生的角色间的冲突和压力,会对员工的生活满意感造成负面影响。本研究认为适宜的个人应对策略能够调节这两者之间的关系,通过对某国有企业193名被试的问卷调查,得出以下结论：1）工作－家庭冲突和家庭－工作冲突对生活满意感都有显著的负面影响;2）员工家庭优先策略能够缓解工作－家庭冲突对生活满意感的负面影响,员工工作完美策略能够缓解家庭,工作冲突所带来的压力感。     

用于视觉导航中的摄像机标定方法研究

为了解决摄像机标定的非线性优化过程中解的不稳定性问题,提出了一种线性的摄像机标定方法.该方法首先利用透视投影的交比不变性原理,在畸变模型为一阶径向畸变的情况下,根据空间共线4点的图像坐标及其交比,线性标定出摄像机镜头的畸变参数;然后,基于考虑径向畸变的摄像机成像模型的约束关系.线性标定出其他摄像机参数.实验结果表明,该方法标定模板制作简单,操作方便,具有一定的鲁棒性,可以满足农业机器人视觉导航中的精度要求.     

Subjective confidence in forecasts: A response to fischhoff and MacGregor

Here we evaluate the generalizability of calibration studies which have used general knowledge questions, and argue that on conceptual, methodological and empirical grounds the results have limited applicability to judgemental forecasting. We also review evidence which suggests that judgemental forecast probabilities are influenced by variables such as the desirability, imminence, time period and perceived controllability of the event to be forecast. As these variables do not apply to judgement in the domain of general knowledge, a need for research recognizing and exploring the psychological processes underlying uncertainty about the future is apparent.     

汽车与行人交通冲突中驾驶员操作特性研究

在北京50辆出租车上安装了图像式行驶记录仪,进行了为期一年真实道路环境下的交通冲突调查。本文基于收集的交通冲突数据,从冲突时间、地点、自车速度和驾驶员的制动操作等方面对车辆与行人的冲突特征进行分析,提出了车与行人冲突发生的原因,为汽车与行人事故的预防提供了理论基础。     

基于LabVIEW的加速度传感器静态标定系统的设计

为了提高加速度传感器批量生产的效率,加速度传感器静态标定系统不但要能标定多个不同量程的加速度传感器,而且能够对标定结果进行检测、显示和保存。针对这一需求,设计了以精密离心机、NRF24L01射频模块、微控制器为硬件平台,以Lab-VIEW为软件平台的加速度传感器静态标定系统。结果表明：该系统具有效率高、精度高、稳定性好、人机交互友善等特点。