基于分层次聚类的MIDI音乐主旋律提取方法

为了准确提取多音轨MIDI主旋律,同时减小主旋律分布在乐器音轨或音高较弱部分所产生的提取误差,提出了基于分层次聚类的多音轨MIDI主旋律提取方法。首先解析MIDI音乐文件,然后去除每一音轨中的控制音符和不包含旋律信息的音轨,通过归并到文该文件中的具有音高柱状图特征的音符集,从而提取出主旋律。通过与人工标识结果的实验进行比较,表明该提取主旋律方法的准确性。     

Extraction of melody from polyphonic music using modified morlet wavelet

In this paper, the extraction of melody for polyphonic music is discussed. The method proposes a simple but effective modification in the Morlet wavelet as a modified Morlet wavelet (MMW). The pitch detection concept is applied to the transformed wavelet music signal for primary melody estimation and extraction. The proposed method is then compared with three other methods reported in the literature (the method focused on Short Time Fourier Transform, multi-resolution Fast Fourier Transform, and Morlet Wavelet). The percentage gross pitch error (GPE) parameter is considered for purposes of comparison. In comparison, it is observed that the proposed approach has the lowest GPE. The simulation results also present a lower percentage error in the predominant pitch frequency estimation for the proposed method.     

Stability independent of delay using rational functions

This paper is concerned with the problem of assessing the stability of linear systems with a single time-delay. Stability analysis of linear systems with time-delays is complicated by the need to locate the roots of a transcendental characteristic equation. In this paper we show that a linear system with a single time-delay is stable independent of delay if and only if a certain rational function parameterized by an integer k and a positive real number T has only stable roots for any finite T≥0 and any k≥2. We then show how this stability result can be further simplified by analyzing the roots of an associated polynomial parameterized by a real number δ in the open interval (0,1). The paper is closed by showing counterexamples where stability of the roots of the rational function when k=1 is not sufficient for stability of the associated linear system with time-delay. We also introduce a variation of an existing frequency-sweeping necessary and sufficient condition for stability independent of delay which resembles the form of a generalized Nyquist criterion. The results are illustrated by numerical examples.     

Arbitrary terminated negative group delay circuit using signal interference concept

In this article, we demonstrate signal interference concept based wideband negative group delay (NGD) circuit with an arbitrary termination port impedance. The proposed circuit consists of unequal power division ratio 180° hybrid and in‐phase combiner. The NGD can be generated by controlling power division ratios of 180° hybrid and combiner. For experimental verification, the circuit is designed and fabricated at a center frequency of 2 GHz. The experiment results show that the proposed NGD circuit can provide 460 MHz NGD bandwidth (bandwidth of group delay <0 ns) with group delay of ?0.8 ns at 2 GHz.     

Literature extraction of protein functions using sentence pattern mining

With the rapid growth of articles of genomics research, it has become a challenge for biomedical researchers to access this ever-increasing quantity of information to understand the newest discovery of functions of proteins they are studying. To facilitate functional annotation of proteins by utilizing the huge amounts of biomedical literature and transforming the knowledge into easily accessible database formats, the text mining technique thus becomes essential. In this paper, we propose the method of sentence pattern mining to extract protein functions from biomedical literature. To recognize variants of function terms correctly, we identify morphological, syntactic, and semantic variation forms. The proposed methods can be used to aid database curators in annotating protein functions and to assist biologists and medical researchers in searching protein functions from biomedical literature.     

Multicast routing for delay variation bound using a modified ant colony algorithm

The delay and delay variation-bounded Steiner tree problem is an important multicast routing problem in real-time multimedia networks. Such a constrained Steiner tree problem is known to be NP-complete. This paper proposes an ant colony algorithm with orientation factor and applies it to multicast routing problem with the constraints of delay variation bound. The orientation factor enables the ant to get rid of the initial blindness when searching paths, makes use of the search results and reduces the misguiding effect of pheromone on irrelevant paths, thus overcoming the drawbacks of slow convergence existing in the basic ant colony algorithm, increasing the speed of convergence and speeding up the finding of feasible solution to the problem. The simulation results show that the modified algorithm makes it possible to find a feasible solution to the multicast routing problem with delay variation bound. Compared with the conventional ant colony algorithm, the convergence speed of the modified algorithm is improved.     

Design of fuzzy PID controllers using modified triangular membership functions

A design method for fuzzy proportional-integral-derivative (PID) controllers is investigated in this study. Based on conventional triangular membership functions used in fuzzy inference systems, the modified triangular membership functions are proposed to improve a system’s performance according to knowledge-based reasonings. The parameters of the considered controllers are tuned by means of genetic algorithms (GAs) using a fitness function associated with the system’s performance indices. The merits of the proposed controllers are illustrated by considering a model of the induction motor control system and a higher-order numerical model.     

基于MCU硬件的音乐节奏提取系统

提出了一种基于微控制器(MCU)的实时音乐节奏提取系统.该系统能够准确地提取节奏感较强的乐曲节奏,并按照设定的增益要求控制音频放大系统的增益.经处理得到的输出音乐节奏和音频能量作为控制信号调节音乐喷泉的花型变换节奏以及水柱高度.     

Numerical solution of system of first-order delay differential equations using polynomial spline functions

The use of two constructed polynomial spline functions to approximate the solution of a system of first-order delay differential equations is described. The first spline function is a polynomial with an undetermined constant coefficient in the last term. The other has a polynomial spline form. The error analysis and stability of the second function are theoretically investigated and a test example is given. A comparison of the two forms is carried out to illustrate the pertinent features of the proposed techniques.     

A self‐matched negative group delay circuit with tunable center frequency and group delay

A compact self‐matched negative group delay circuit (NGDC) with tunable center frequency and tunable group delay (GD) is proposed. Two varactors and a variable resistor are utilized to implement the tunability of the center frequency and GD of the proposed NGDC. To verify the design concept, a tunable NGDC is designed and fabricated. The measured center frequency is tuned from 0.8 to 1.3 GHz and the measured NGD time is tuned from ?1 to ?10 ns. The insertion loss varies from 16.0 to 34.5 dB. In the process of tuning the center frequency and NGD time, the return losses keep better than 30 dB.     

基于音乐旋律轮廓的特征提取算法

提出了一种基于音乐旋律轮廓的特征提取算法。该算法从哼唱片断中提取出歌曲基音序列,经规整、合并、分段后转化为旋律轮廓序列,然后使用标准音调生成的标准音调差值表将此序列转化为旋律轮廓特征。结果表明,该系统对环境噪声有较好的鲁棒性;在含有405首歌曲的搜索空间中,检索前5位成功率超过90%。     

多声部乐谱音符基元抽取方法

面向复杂版面的多声部乐谱,提出了符干、符头和符梁三类音符基元的抽取方法。提出基于垂直游程编码的粗提取、基于水平游程编码的精检测的符干抽取方法,能够有效克服基元间密集相交、粘连的干扰;在音符先验知识引导下,提出先分割、后特征检测的符头抽取方法,解决了粘连符头的切分难题;提出一种基于块状体分割和特征检测的符梁抽取方法,避开了传统的直线抽取方法所无法处理的符梁粘连难题。实验结果表明,该方法能够有效抽取复杂环境下多声部乐谱的音符基元。     

Synthesis of frequency‐independent phase shifters using negative group delay active circuit

This article describes a synthesis method dedicated to the design of frequency‐independent phase shifters (PSs). This innovative PS structure consists in a transmission line cascaded with a negative group delay (NGD) active circuit so that the absolute constant group delays generated by both of them are identical but of opposite signs. So, in principle, it exhibits a constant overall phase and a group delay close to zero. Broadband linear positive phase slopes are obtained through use of an NGD active circuit whose characteristics are recalled prior to the extraction of the PS synthesis relations. The design and simulations of a PS of compact size are reported. The experimental results confirm the expected frequency‐independent transmission‐phase value of 145° ± 10° with an insertion gain of 2 ± 2 dB over a 160% relative frequency band. At last, future prospects allowed by the specific properties of this PS are presented. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2010.     

基于谐波的乐纹提取和音乐检索

提出了一种基于节拍内音乐谐波特性的乐纹特征提取方法,首先求得每帧音乐的谐波信息,再利用跟踪得到的节拍,计算节拍内所有帧的谐波信息的均值,构成此节拍的乐纹特征矩阵。为了提高音乐检索的效率,设计了一个二级音乐检索算法：根据节拍信息,将与查询音乐片段的每分钟节拍数相近的音乐作为候选音乐,再逐节拍计算所查询音乐的乐纹和候选音乐乐纹的相似度,选择相似度最高的音乐作为检索结果。实验结果表明,提出的乐纹特征和音乐检索算法有效地提高了检索准确率和检索效率。     

Structure extraction from decorated characters using multiscaleimages

Decorated characters are widely used in various documents. Practical optical character reader is required to deal with not only common fonts but also complex designed fonts. However, since the appearances of decorated characters are complicated, most general character recognition systems cannot give good performances on decorated characters. In this paper, an algorithm that can extract character's essential structure from a decorated character is proposed. This algorithm is applied in preprocessing of character recognition. The proposed algorithm consists of three procedures: global structure extraction, interpolation of structure and smoothing. By using multiscale images, topographical features, such as ridges and ravines are detected for structure extraction. Ridges are used for extracting global structure and ravines are used for interpolation. Experimental results show character structures can be clearly extracted from very complex decorated characters     

流行音乐主旋律提取技术综述

旋律是最重要的音乐要素之一,多应用于音乐内容分析、音乐创作、音乐教育、抄袭检测等方面。主旋律提取旨在从一段音乐中自动估计对应于主旋律单音音符序列的音高或基频。流行音乐一般属于复杂的多音音乐,因此主旋律提取面临着许多挑战。综述了主旋律提取的研究背景,将主旋律提取的典型方法分别从基于音高显著度、基于声源分离以及其他方法3个类别进行了阐述,最后介绍了主旋律提取的评价指标以及研究进展。     

Calculation of associated functions for rational modified weight functions

Let be a sequence of polynomials orthogonal with respect to a measure dω on the real line and the sequence of their associated functions (they are essentially the Hilbert transforms of these polynomials). We show how to get associated functions Q _n ^[m,l] if the measure dω changes to , where Φ_m and ϕ _l are polynomials of degree m resp.l. The results can be used for example to construct Gaussian quadrature rules for rational modified weight functions.     

Solution of time-varying delay systems by hybrid functions

A method for finding the solution of time-delay systems using a hybrid function is proposed. The properties of the hybrid functions which consists of block-pulse functions plus Legendre polynomials are presented. The method is based upon expanding various time functions in the system as their truncated hybrid functions. The operational matrices of product and delay are introduced. These matrices together with the operational matrix of integration are utilized to reduce the solution of time-delay systems to the solution of algebraic equations. Illustrative examples are included to demonstrate the validity and applicability of the technique.