利用频率掩蔽法设计均匀和非均匀余弦调制滤波器组

给出了一种均匀非均匀余弦调制滤波器组的设计方法。采用了频率掩蔽法设计原型滤波器,利用迭代算法优化原型滤波器的脉冲响应系数,目标函数表示为脉冲响应系数的四次方,非均匀余弦调制滤波器组通过合并均匀余弦调制滤波器组的相邻的滤波器得到,这种方法简单有效。最后的Matlab实例仿真验证了此算法的有效性。     

呋喃酮及其在食品饮料等方面的应用

4－羟基－2，5－二甲基－3（2H）呋喃酮（简称：呋喃酮或菠萝酮）是近年来国际上广泛应用于食品，饮料，香烟，保健品，饲料等方面的新型食品香味料，本就它的合成方法，性质，功能和应用方面作简单的介绍。     

Masking by object substitution: Dissociation of masking and cuing effects.

In a newly discovered form of visual masking, a target stimulus is masked by 4 flanking dots if their offset is delayed relative to the target (V. Di Lollo, J. T. Enns, & R. A. Rensink, 2000). In Di Lollo et al. (2000), the dot pattern also cued the relevant target and therefore required deliberate attention. In the present Experiments 2-6, a central arrow cued 1 of 2 letters for an E/F discrimination, with dots flanking both letters. Masking was reduced compared with the mask-cue procedure but was still robust. Delayed-offset dots flanking the nontarget also impaired performance, indicating competition for attention. Masking was unaffected by brightness of the dots relative to the target. Masking was attenuated not only by precuing attention to the target location but also by preview of an uninformative dot mask. Theories of masking by object substitution must therefore accommodate the prior context into which the target stimulus is introduced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object trimming: When masking dots alter rather than replace target representations.

Five experiments demonstrate that when dots appear beside a briefly presented target object, and persist on view longer than the target, the flanked object is perceptually altered by the dots. Three methods are used to explore this object trimming effect. Experiments 1–3 assess participants’ conscious reports of trimmed digits, Experiment 4 uses repetition priming to explore the target representation, and Experiment 5 examines the perception of apparent motion in trimmed targets. Results of all three methods indicate that object trimming is influenced by mechanisms of perceptual grouping that operate on target representations prior to conscious access. Separate contributions from visual crowding and backward masking are also identified. These results imply that common-onset masking does not always result from the target being substituted by the mask, but that target and mask can sometimes maintain separate mental representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Light aversion in mice depends on nonimage-forming irradiance detection.

Detection of light in the eye underlies image-forming vision, but also regulates adaptive responses in physiology and behavior. Typically these adaptive responses do not involve image-forming vision, but depend on a relatively absolute measure of brightness (nonimage-forming irradiance detection). The goal of this study was to further understand how image-forming vision and nonimage-forming irradiance detection contribute to the effects of light on behavior. Three light dependent behaviors were assessed in wild-type, Rpe65-/- and rd1 mice. In Rpe65-/- mice, nonimage-forming irradiance detection is severely attenuated, but rod based visual acuity is relatively preserved. In rd1 mice visual acuity is nonrecordable, but nonimage-forming responses are less severely attenuated than Rpe65-/-. Positive masking, an image-forming vision dependent increase in wheel running, was absent in rd1 and restricted to higher irradiances in Rpe65-/-. Negative masking, a suppression of wheel running sensitivity with nonimage-forming irradiance detection input, was increased in rd1, but reduced in Rpe65-/- mice. By contrast, light aversion, an avoidance of brightly lit areas, was abolished in both Rpe65-/- and rd1. This shows that image-forming vision is not sufficient for light aversion, suggesting nonimage-forming irradiance detection motivates this behavior. Further, the differing effects of disease suggest that negative masking and light aversion are distinct responses with specialized nonimage-forming irradiance detection pathways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention and distractor frequency in naming performance: Comment on Dhooge and Hartsuiker (2010).

E. Dhooge and R. J. Hartsuiker (2010) reported experiments showing that picture naming takes longer with low- than high-frequency distractor words, replicating M. Miozzo and A. Caramazza (2003). In addition, they showed that this distractor-frequency effect disappears when distractors are masked or preexposed. These findings were taken to refute models like WEAVER++ (A. Roelofs, 2003) in which words are selected by competition. However, Dhooge and Hartsuiker do not take into account that according to this model, picture-word interference taps not only into word production but also into attentional processes. Here, the authors indicate that WEAVER++ contains an attentional mechanism that accounts for the distractor-frequency effect (A. Roelofs, 2005). Moreover, the authors demonstrate that the model accounts for the influence of masking and preexposure, and does so in a simpler way than the response exclusion through self-monitoring account advanced by Dhooge and Hartsuiker. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Combined FRM and GDFT filter bank designs for improved nonuniform DSA channelisation

Multistandard channelisation for base stations is a big application of generalised discrete Fourier transform modulated filter banks (GDFT‐FBs) in digital communications. For technologies such as software‐defined radio and cognitive radio, nonuniform channelisers must be used if frequency bands are shared by different standards. However, GDFT‐FB‐based nonuniform channelisers can suffer from high filter orders when applied to wideband input signals. In this paper, various combinations of GDFT‐FB with the frequency response masking technique are proposed and evaluated for both uniform and nonuniform channelisation applications. Results show that the proposed techniques achieve savings in both the number of filter coefficients and the number of operations per input sample. Copyright © 2015 John Wiley & Sons, Ltd.     

萃取分析时最低掩蔽剂浓度的简便计算方法

提出一种萃取分析时掩蔽剂最低浓度的简便计算公式:lg[R]=1b[lgKe+nlg[HLn(o)]+npH-lgβb+3+lgVV((wo))],式中Ke为干扰金属离子与萃取剂配合物的萃取平衡常数,[HLn(o)]为萃取剂在有机相的浓度,V(o)和V(w)分别为有机相和水相的体积,n、b分别为干扰金属离子与萃取剂配合物的最大配位数和溶液中干扰金属离子与掩蔽剂配合物浓度最大配离子的级数。β为干扰金属离子与掩蔽剂配合物的累积稳定常数。求解时,我们从第一级配离子浓度最大开始,若计算出的[R]位于第一级配离子浓度最大的自由配体浓度范围,则此时的[R]即为计算结果;否则试探下一级配离子直至位于其浓度范围。得到了[R]后,由酸效应系数可计算出掩蔽剂的最小浓度。     

基于掩模经验模态分解的风速组合预测模型

在风电预测中,传统的经验模态分解法将风速信号分解为若干具有不同特征尺度的数据分量时,其所得分量可能存在模态混叠现象,影响风速预测的精度。为此,提出一种基于掩模经验模态分解法和遗传神经网络的风速预测组合模型。首先,通过掩膜信号法（masking signal,MS）对经验模态分解法进行改进,将风速信号分解为频率相对固定、更为平稳的分量。之后,利用遗传神经网络算法分别对这些分量进行预测,将各分量预测结果叠加后得到最终风速预测值。通过C++语言编程进行算法实现,采用实际风场数据进行仿真,其结果表明,所提方法计算时间较短,预测精度较高,特别适用于在线超短期（10 min）和短期（1 h）的风速预测,具有实际的工程应用价值。     

基于人眼视觉特性的低比特率图像压缩编码

为了提高编码速度和改进视觉效果,提出了一种改进的低比特率SPIHT算法。算法首先用提升小波对原始图像进行分解,再结合人眼视觉掩蔽特性,对不同区域内图像信息所对应的小波系数赋予不同视觉权值,以保证优先传输视觉上的最重要系数,最后根据系数重要性,对低频系数采用新的排列结构,并采用SPIHT编码思想完成图像压缩。实验结果表明,该算法压缩效果优于SPIHT图像压缩方案,特别在低比特率下。