A backward procedure for change-point detection with applications to copy number variation detection

Change-point detection regains much attention recently for analyzing array or sequencing data for copy number variation (CNV) detection. In such applications, the true signals are typically very short and buried in the long data sequence, which makes it challenging to identify the variations efficiently and accurately. In this article, we propose a new change-point detection method, a backward procedure, which is not only fast and simple enough to exploit high-dimensional data but also performs very well for detecting short signals. Although motivated by CNV detection, the backward procedure is generally applicable to assorted change-point problems that arise in a variety of scientific applications. It is illustrated by both simulated and real CNV data that the backward detection has clear advantages over other competing methods, especially when the true signal is short. The Canadian Journal of Statistics 48: 366–385; 2020 © 2020 Statistical Society of Canada     

P帧快速模式选择算法

针对H.264编码算法中,预测帧(P帧)编码模式的选择过程异常复杂,开销大的问题,提出了一种新的快速模式选择算法,该算法利用直流系数能预先判定P帧编码模式的有效范围,缩小备选编码模式的可选范围,从而使模式选择的复杂度大为降低。实验结果表明,该算法可以使编码时间降低54%～74%,峰值信噪比提高0.05 dB～0.17 dB,同时码率变化范围为-3.14%～3.97%。应用结果表明,该算法在基于TI's TMS320DM642视频压缩系统中1路D1视频的压缩速度为25帧/s。     

On simple wavelet estimators of random signals and their small-sample properties

In the paper we suggest certain nonparametric estimators of random signals based on the wavelet transform. We consider stochastic signals embedded in white noise and extractions with wavelet denoizing algorithms utilizing the non-decimated discrete wavelet transform and the idea of wavelet scaling. We evaluate properties of these estimators via extensive computer simulations and partially also analytically. Our wavelet estimators of random signals have clear advantages over parametric maximum likelihood methods as far as computational issues are concerned, while at the same time they can compete with these methods in terms of precision of estimation in small samples. An illustrative example concerning smoothing of survey data is also provided.     

Optimal design of the variable sampling size and sampling interval variable dimension T2 control chart for monitoring the mean vector of a multivariate normal process

This paper develops the algorithm for the optimization designs of the adaptive T² Control Chart for Monitoring the Mean Vector of a Multivariate Normal Process. It includes the variable sample size, variable sampling interval and variable dimensional chart. The VDT² control chart performs well for moderate and large shifts in the mean vector. However, its performance for small shifts is poor. To improve the chart's performance in detecting such shifts, we propose the application of the variable sample size and sampling interval technique to the VDT² control chart, resulting in the VSSIVDT² control chart.     

交叉口信号配时的人工蚂蚁优化

针对我国城市道路交叉口的实际情况，在改进信号配时模型的基础上，采用一种新型随机搜索思想——人工蚂蚁优化算法来解决交叉口的信号配时问题．仿真试验表明，所得结果优于经典方法，在相同的信号周期内，降低了交叉口的总延误时间和停车次数，提高了通行能力．     

基于FrFT和子空间正交的LFM信号参数估计

基于分数阶Fourier变换和子空间正交性,提出了一种低信噪比下线性调频信号检测与参数估计方法。讨论过程中将线性调频信号通过适当的分数阶Fourier变换得到一个单频复正弦信号,在此基础上,利用信号子空间与噪声子空间的正交性处理其正弦信号,再对线性调频信号的检测和参数估计转化为函数极值求解;最后,利用计算机模拟证实了方法的有效性。     

耦合腔行波管三维大信号程序设计

讨论了耦合腔行波管大信号互作用的物理模型和三维计算机程序设计，考虑了电子注的圆环模型在径向、轴向的速度以及圆环旋转的角速度，详细研究了电子注对场的激励形式、返波的影响和相对论修正等因素，编制出了耦合腔行波管三维大信号程序。计算结果与实际相符。     

Signal crimes and signal disorders: notes on deviance as communicative action

In this paper a 'signal crimes' perspective is outlined in an effort to unpack the relationships between experiences of crime and disorder, and perceptions of criminogenic risk. Grounded in symbolic interactionist sociology, and developing a social semiotic understanding of risk perception, it is a perspective that focuses upon processes of social reaction and the ways in which people interpret and define threats to their security. It is proposed that people interpret the occurrence of certain incidents as 'warning signals' about the levels of risk to which they are either actually or potentially exposed. These signals tend to take the form of signal crimes and/or signal disorders and are important in terms of how social space is symbolically constructed.