A New Recursive Parameter Estimation Algorithm of Multi－Variable Time－Varying AR Model

ＡＮｅｗＲｅｃｕｒｓｉｖｅＰａｒａｍｅｔｅｒＥｓｔｉｍａｔｉｏｎＡｌｇｏｒｉｔｈｍｏｆＭｕｌｔｉ－ＶａｒｉａｂｌｅＴｉｍｅ－ＶａｒｙｉｎｇＡＲＭｏｄｅｌＺｅｎｇＰｅｎｇ（曾鹏）ＷａｎｇＳｈａｏｄｉ（王绍棣）（ＮａｎｊｉｎｇＵｎｉｖｅｒｓｉｔｙｏｆＰｏ...     

贝叶斯统计的发展及其争鸣

概述了贝叶斯统计的基本思想,通过实例分析了确定先验信息方法的思维合理性。探讨了贝叶斯统计未来理论发展及其应用空间。     

Climate change by the numbers: Leveraging mathematical skills for science learning online

The purpose of this preregistered study was to test an online intervention that presents participants with novel numbers about climate change after they estimate those numbers. An experimental study design was used to investigate the impact of the intervention on undergraduate students’ climate change understanding and perceptions that human caused climate change is plausible. Findings revealed that posttest climate change knowledge and plausibility perceptions were higher among those randomly assigned to use the intervention compared with those assigned to a control condition, and that supplementing this experience with numeracy instruction was linked with the use of more explicit estimation strategies and greater learning gains for people with adaptive epistemic dispositions. Findings from this study replicate and extend prior research, support the idea that novel data can support knowledge revision, identify estimation strategies used in this context, and offer an open-source online intervention for sharing surprising data with students and teachers.     

A fast motion estimation algorithm for mobile communications

The limitation of processing power, battery life and memory capacity of portable terminals requires reducing encoding complexity in mobile communications. Motion estimation (ME) is the most computationally intensive module in a typical video codec, which determines not only the encoder's performance but also the reconstructed video quality. In this paper, a fast ME algorithm for H.264/AVC baseline profile coding is proposed based on the analysis of motion vector field and error surface, and the statistical distributions of different type macroblocks (MBs). Simulation results showed that: in comparison with MVFAST, the proposed algorithm can decrease the computational load over 7.2% with no requirement of expanding memory capacity while maintaining the same video quality as MVFAST. Furthermore, its simplicity makes it easy to be implemented on hardware.     

基于虚功误差估计算子服役结构状态评估的统计分析

针对服役结构状态评估问题提出了基于虚功误差估计算子的统计分析方法.首先定义虚功误差来表达实际结构与参数化分析模型之间的差别,然后采用改进的牛顿算法推导分析模型结构识别算法.为了探讨在有测量误差的情况下算法的性能,引用Monte Carlo方法模拟测量数据,对测量数据的误差与识别结果的影响进行了详细的分析比较.根据识别结果确定它的概率分布,通过假设试验对服役结构状态评估进行统计分析.最后应用双跨五层刚架结构进行了大量数值模拟,计算结果显示了所提方法的有效性.     

MIMO-QAM系统载波频偏估计

本文在分析MIMO-QAM系统可行性的基础上,提出了一种频偏估计算法,并进行了仿真。该算法利用帧同步序列,优化系统资源配置。仿真结果表明,本文提出的算法是可行的,具有较高的精度和实用价值。     

等比数列应力条件下产品寿命的参数估计

通过讨论产品寿命服从指数分布的情况、等比数列应力加速寿命的分布函数及数学模型,给出了相对应的标准时间下的参数估计.     

Linex损失及NA样本下单边截断型分布族参数函数的EB估计

本文在Linex损失函数下,充分运用同分布NA样本密度函数的核估计方法,构造了一类单边截断型分布族参数函数的EB估计,并建立了它的收敛速度,在一定条件下这个收敛速度可充分接近1.     

A Technical Note on IRT Simulation Studies: Dealing With Truth,Estimates, Observed Data,and Residuals

Simulation studies are extremely common in the item response theory (IRT) research literature. This article presents a didactic discussion of “truth” and “error” in IRT‐based simulation studies. We ultimately recommend that future research focus less on the simple recovery of parameters from a convenient generating IRT model, and more on practical comparative estimation studies when the data are intentionally generated to incorporate nuisance dimensionality and other sources of nuanced contamination encountered with real data. A new framework is also presented for conceptualizing and comparing various residuals in IRT studies. The new framework allows even very different calibration and scoring IRT models to be compared on a common, convenient, and highly interpretable number‐correct metric. Some illustrative examples are included.     

Technical efficiency and productivity for higher education institutions in Sweden

This study investigates technical efficiency and productivity for Swedish higher education institutions (HEIs). One identified problem in previous research concerns adjusting efficiency scores for input quality. This problem is avoided using grades from upper-secondary schools. A second problem concerns heterogeneity with respect to subjects and institutions between HEIs. Using the Swedish national resource allocation system, students are weighted according to subject. For research production, a bibliometric index that allows for differences in publication tradition is used. A third problem when using the data envelopment analysis approach is the lack of statistical inference. Bootstrapping is used to approach this problem. The results indicate an average inefficiency of 12% and a productivity increase of around 1.7% per year.