The costs and benefits of tonal centers for chord processing.

Harmonic priming studies have shown that a musical context, with its established tonal center, influences target chord processing. This study investigated costs and benefits of priming tonal centers for target processing by adding a baseline condition (sequences without a specific tonal center). Results confirmed harmonic priming, with faster processing for related than for unrelated and less related targets (tonic chord, out-of-key chord, subdominant chord). Comparing targets in baseline contexts with targets in sequences with well-established tonal centers revealed a benefit of processing for related targets but a cost of processing for unrelated and less related targets. Findings are discussed in terms of tonal knowledge activation and suggest that an activated tonal center gives rise to strong expectations for the tonic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于一种超分辨率算法的三维散射中心提取方法

针对转台-弧形导轨测量方法,在二维MEMP方法的基础上,提出一种适用于三维散射中心提取的超分辨率算法.该方法利用Hankel矩阵的结构特性,以及子空间不变技术等,实现对信号三维参数的正确估计,并且无需额外的配对步骤.对八个散射点组成的立方体模型的数值仿真表明,该算法可以正确估计信号参数对,并对噪声的鲁棒性较强.进一步将三维参数估计问题扩展到N维情况,给出了具有较普遍意义的N维参数估计公式.     

Leakage radiation microscopy of surface plasmons launched by a nanodiamond-based tip

Leakage-radiation microscopy of a thin gold film demonstrates the ability of an ensemble of fluorescent diamond nanoparticles attached onto the apex of an optical tip to serve as an efficient near-field surface-plasmon polariton launcher. The implementation of the nanodiamond-based tip in a near-field scanning optical microscope will allow for an accurate control on the launching position, thereby opening the way to scanning plasmonics.     

A numerical database for ultrasonic defect characterisation using array data: Robustness and accuracy

Elastodynamic scattering matrices are known to contain geometrical information about a given scatterer, such as its size and shape. Here, the extent to which this scattered information can be retrieved using an ultrasonic array and used to characterise defects for Non-Destructive Evaluation is explored. Experimentally measured defect scattering matrices are compared to a database of possible scatterers and the nearest neighbour used to characterise the defect's geometry in terms of crack length and orientation. As an example, a database of scattering matrices for small (lengths 0.2–2.0 mm) cracks at a range of frequencies (2–20 MHz) is formed. The short range similarity (i.e. that between close neighbours) and the long range similarity (i.e. uniqueness) are used to understand the uncertainties inherent in this approach. In addition, the effect of spatially coherent noise, such as grain scattering in a polycrystalline metal, on the scattered information content is quantified. It is shown that as the noise level or frequency increases, so the information retrievable from a given crack is reduced, setting bounds on the accuracy of characterisation possible from a given ultrasonic dataset.     

矿井隧道中电磁场能量的损耗

运用复玻印亭定理 ,研究了圆空矿井隧道中电磁场能量衰减和转换的方式 ,证明了圆空隧道中电磁功率的流失发生在隧道壁交界面处 .进而证明了圆形隧道充满煤介质时能量损耗与其电导率有关 ,隧道中悬浮的粉尘在电磁场作用下发生瑞利散射 ,散射功率的一部分构成损耗 ,能量损耗与粉尘分布密度成正比 .     

矩形波导填充带有空气柱介质不连续性的边界元法分析

应用边界元法分析了矩形波导中填充带有空气柱介质不连续性的散射特性，编制了一个通用的计算机程序，对几个算例进行了计算。数值结果表明了该方法的有效性。     

Approximation and analysis of a call center with flexible and specialized servers

This paper describes a decomposition algorithm to estimate the performance of a call center with two types of customers and two server categories. In this system specialized servers can process only one customer type, while flexible servers handle both types. The algorithm divides the systems state space into regions, and simple approximate models find the conditional system performance within each region. While the procedure described here is tailored for a system with a priority queue discipline and two customer classes, it can be adapted for systems with FCFS queue disciplines and for systems with more than two customer types. Performance measures generated by the procedure are sufficiently accurate for many service system design decisions, such as setting telephone call center staffing levels and long-term capacity planning. The procedure is also extremely fast, and its computational requirements do not grow with system congestion. Numerical tests demonstrate that its running time is significantly lower than traditional numerical methods for generating approximations. As an example of its use, we employ the procedure to demonstrate the benefits of server flexibility in a particular telephone call center.The author thanks Gregory Dobson, who participated in the initial consulting project and problem formulation, as well as Paul Schweitzer, Harry Groenevelt, and two anonymous referees for their helpful suggestions.     

A direct method for cluster analysis

An algorithm based on a least-mean-square (LMS) criterion is presented. This algorithm partitions a multi-dimensional data set directly into a desired number of clusters. The result is compared favorably to existing methods in both performance and computational efficiency. An efficient method for determining a reasonable set of distributed initial cluster centers based on principal component analysis is also presented. This clustering algorithm is shown to converge to a unique minimum based on the LMS criterion and is demonstrated by digital computer simulation and applied to the analysis of vectorcardiograms.     

Au/锗/氧化硅纳米多层膜/p-Si结构的电致发光机制研究

用射频磁控溅射法制备了锗/氧化硅纳米多层膜,在室温下测量了Au/锗/氧化硅纳米多层膜/pSi结构的电致发光.利用位形坐标模型分析了锗/氧化硅纳米多层膜的发光中心,并用量子限制-发光中心模型对该纳米结构的电致发光过程作了研究,研究表明锗/氧化硅纳米多层膜的电致发光主要来自SiO2层的发光中心.