The Overconfident Principles of Economics Student: An Examination of a Metacognitive Skill

Students in a large principles of macroeconomics class were asked to predict their performance on a regularly scheduled midterm examination. The author collected and analyzed data to examine the effect of various demographic characteristics, academic endowments, course preparation, and course performance variables on the accuracy of pretest expectations. A two-equation recursive model was estimated by the author to determine which factors influenced the accuracy of student expectations (predictive calibration). The results indicated that a pervasive degree of overconfidence existed within the sample. Although age and overall academic performance were found to temper overconfidence, students with credit in a previous economics course had a greater probability of reporting overconfident expectations. Overconfidence was found to be associated with lower degrees of predictive calibration. Misjudgments concerning the scope of the midterm were found to lower predictive calibration scores, ceteris paribus. These and other results indicate that unmet student performance expectations may be a root cause for the routinely observed student dissatisfaction within the traditional principles course.     

全站仪法在检定立式金属罐容积中的应用

作为一种新技术、新方法,全站仪法在检定立式金属罐容积中的应用刚刚起步。简述了全站仪法的检定工作原理、方式和技术特点．着重表述了全站仪法适合检定立式金属罐的容积范围及检定结果不确定度的分析,并对该方法的计量检定结果与光学参比线法的检定结果作了比较。     

Coupling index and stocks

In this paper, we are interested in continuous-time models in which the index level induces feedback on the dynamics of its composing stocks. More precisely, we propose a model in which the log-returns of each stock may be decomposed into a systemic part proportional to the log-returns of the index plus an idiosyncratic part. We show that, when the number of stocks in the index is large, this model may be approximated by a local volatility model for the index and a stochastic volatility model for each stock with volatility driven by the index. This result is useful from a calibration perspective: it suggests that one should first calibrate the local volatility of the index and then calibrate the dynamics of each stock. We explain how to do so in the limiting simplified model and in the original model.     

JOINING EUROPEAN MONETARY UNION: A REAL OPTIONS PERSPECTIVE

We examine the real option implicit in countries' decisions on whether to join a monetary union when future benefits of this move are uncertain. Our theoretical model is calibrated for the current Euro‐12 area and EU‐15 outs, proxying policymakers' inflation preferences with unemployment rates, debt‐to‐GDP and potential‐to‐actual‐GDP ratios. The Euro‐12 area is generally ready or close to wanting to expand, whereas the EU‐15 outs are unready to make that move at present and have widely varying probabilities of wanting to do so in the future, depending on the measure used.     

大口径天线多模馈源跟踪系统校相参数的计算

基于测控系统常用的大口径天线多模馈源跟踪系统校相需求,介绍了当前常用的校相方法,针对太阳校相单次校相结果误差大、需取均值使用导致校相周期长等缺点,通过分析多模馈源跟踪系统工作原理,提出了一种基于固定波程差的校相参数计算方法。该方法利用不同频点的精确校相值标定跟踪系统和、差通道之间波程差,进而计算出整个频段中各频点校相值。最后结合靶场遥测设备进行计算验证,应用表明该方法计算快捷,计算结果稳定可用,符合实际数据的变化趋势,能够满足各项实际工程应用需求。     

基于神经网络的数码相机颜色空随转换方法研究

数码相机作为一种常见的图像采集设备被广泛应用,对其进行颜色空间转换的研究具有重要的应用价值。文中研究了基于神经网络的数码相机颜色空间转换中的6个影响因素,提出了利用数据归一化预处理解决函数收敛性问题的方法,并分析了合理设定目标误差对优化系统性能、提高运算效率的作用。实验在2种不同的光源下,采用该转换方法对3款不同型号的数码相机进行研究和评价,得到△E^＊ab≤6的转换结果,证明基于神经网络的数码相机颜色空间转换的实用性。     

试论尿分析仪校准装置计量标准的建立

本文通过对尿液分析仪检验原理的描述及使用方法的介绍,阐明了使用国家标准物质校准尿液分析仪的过程和原理。介绍了测量和数据处理的方法,以及测量结果误差及准确度的评定。     

船载雷达光机轴偏差的动态标校

为解决船载雷达在海上动态情况下雷达光轴与机械轴之间的偏差无法准确标校的问题,提出了采用标校电视反向法瞄船桅光标,在海上动态条件下标校雷达光机偏差的新方法,并分析了该方法的可能误差源,得出改正角误差是反向法光机偏差标校的最大误差源,给出了减少或避免改正角误差的三个解决方法,即智能选择法﹑相对比较法和最小二乘法,利用相对比较法对反向法光机偏差标校数据进行误差修正,标校精度优于10″。试验结果表明,该方法解决了近距离改正角误差较大的技术难题,提高了标校精度,且该方法操作性强,在船载雷达上有较高的实用价值。     

主动雷达与惯导设备安装夹角的标校

针对主动雷达与惯导设备安装夹角引起的测角误差问题，提出了一种高效、高精度的标校方法。采用差分全球定位系统(Global Positioning System,GPS)分别测量目标和雷达在大地坐标系中的位置信息，并转换到目标地理坐标系中；同时通过雷达和惯导测量的雷达坐标系下的目标角度、距离信息，建立目标地理坐标系和雷达坐标系的转换方程，计算出雷达和惯导在目标地理坐标系下的安装夹角。性能分析和仿真结果表明，在确保差分GPS坐标、惯导输出姿态角和雷达测量角精度的条件下，所提方法能有效和高精度的测量出安装夹角。该方法通过了外场试验标定和机载试验验证，可推广到车载或机载雷达与惯导设备的安装夹角标校中。