Frame Length Dependency for Fundamental Frequency Extraction in Noisy Speech

The fundamental frequency plays a significant part in understanding and perceiving the pitch of a sound. The pitch is a fundamental attribute employed in numerous speech-related works. For fundamental frequency extraction, several algorithms have been developed which one to use relies on the signal’s characteristics and the surrounding noise. Thus, the algorithm’s noise resistance becomes more critical than ever for precise fundamental frequency estimation. Nonetheless, numerous state-of-the-art algorithms face struggles in achieving satisfying outcomes when confronted with speech recordings that are noisy with low signal-to-noise ratio (SNR) values. Also, most of the recent techniques utilize different frame lengths for pitch extraction. From this point of view, This research considers different frame lengths on male and female speech signals for fundamental frequency extraction. Also, analyze the frame length dependency on the speech signal analytically to understand which frame length is more suitable and effective for male and female speech signals specifically. For the validation of our idea, we have utilized the conventional autocorrelation function (ACF), and state-of-the-art method BaNa. This study puts out a potent idea that will work better for speech processing applications in noisy speech. From experimental results, the proposed idea represents which frame length is more appropriate for male and female speech signals in noisy environments.

TOPOLOGY OPTIMIZATION OF TRUSS STRUCTURE WITH FUNDAMENTAL FREQUENCY AND FREQUENCY DOMAIN DYNAMIC RESPONSE CONSTRAINTS

In this paper, adaptive genetic algorithm （AGA） is applied to topology optimization of truss structure with frequency domain excitations. The optimization constraints include fundamental frequency, displacement responses under force excitations and acceleration responses under foundation acceleration excitations. The roulette wheel selection operator, adaptive crossover and mutation operators are used as genetic operators. Some heuristic strategies are put forward to direct the deletion of the extra bars and nodes on truss structures. Three examples demonstrate that the proposed method can yield the optimum structure form and the lightest weight of the given ground structure while satisfying dynamic response constraints.

Conformal analysis of fundamental frequency of vibration of simple-supported elastic ellipse-plates with concentrated substance

Aimed at calculating the fundamental frequency of vibration of special-shaped, simple-supported elastic plates, Conformal Mapping theory is applied, and the mathematical method of trigonometric interpolation with interpolation points mutual iterative between odd and even sequences in boundary region is provided, as well as the conformal mapping function which can be described by real number region between complicated region and unit dish region is carried out. Furthermore, in the in-plane state of constant stress, vibrating function is completed by unit dish region method for simple-supported elastic plates with concentrated substance of complicated vibrating region, and the coefficient of fundamental frequency of the plate is analyzed. Meanwhile, taking simple-supported elastic ellipse-plates as an example, the effects on fundamental frequency caused by eccentric ratio, the coefficient of constant in-plane stress, as well as the concentrated substance mass and positions are analyzed respectively.

Integrated design optimization of composite frames and materials for maximum fundamental frequency with continuous fiber winding angles

Fiber reinforced composite frame structure is an ideal lightweight and large-span structure in the fields of aerospace,satellite and wind turbine.Natural fundamental frequency is one of key indicators in the design requirement of the composite frame since structural resonance can be effectively avoided with the increase of the fundamental frequency.Inspired by the concept of integrated design optmization of composite frame structures and materials,the design optimization for the maximum structural fundamental frequency of fiber reinforced frame structures is proposed.An optimization model oriented at the maximum structural fundamental frequency under a composite material volume constraint is established.Two kinds of independent design variables are optimized,in which one is variables represented structural topology,the other is variables of continuous fiber winding angles.Sensitivity analysis of the frequency with respect to the two kinds of independent design variables is implemented with the semi-analytical sensitivity method.Some representative examples in the manuscript demonstrate that the integrated design optimization of composite structures can effectively explore coupled effects between structural configurations and material properties to increase the structural fundamental frequency.The proposed integrated optimization model has great potential to improve composite frames structural dynamic performance in aerospace industries.

A simplified method for analyzing the fundamental frequency of monopile supported offshore wind turbine system design

Preliminary design of offshore wind turbines requires high precision simplified methods for the analysis of the system fundamental frequency. Based on the Rayleigh method and Lagrange’s Equation, this study establishes a simple formula for the analysis of system fundamental frequency in the preliminary design of an offshore wind turbine with a monopile foundation. This method takes into consideration the variation of cross-section geometry of the wind turbine tower along its length, with the inertia moment and distributed mass both changing with diameter. Also the rotational flexibility of the monopile foundation is mainly considered. The rigid pile and elastic middle long pile are calculated separately. The method is validated against both FEM analysis cases and field measurements, showing good agreement. The method is then used in a parametric study, showing that the tower length Lt, tower base diameter d0, tower wall thickness δt, pile diameter db and pile length Lb are the major factors influencing the fundamental frequency of the offshore wind turbine system. In the design of offshore wind turbine systems, these five parameters should be adjusted comprehensively. The seabed soil condition also needs to be carefully considered for soft clay and loose sand.

Analytical Solutions to the Fundamental Frequency of Arbitrary Laminated Plates under Various Boundary Conditions

In recent years, as the composite laminated plates are widely used in engineering practice such as aerospace, marine and building engineering, the vibration problem of the composite laminated plates is becoming more and more important. Frequency, especially the fundamental frequency, has been considered as an important factor in vibration problem. In this paper, a calculation method of the fundamental frequency of arbitrary laminated plates under various boundary conditions is proposed. The vibration differential equation of the laminated plates is established at the beginning of this paper and the frequency formulae of specialty orthotropic laminated plates under various boundary conditions and antisymmetric angle-ply laminated plates with simply-supported edges are investigated. They are proved to be correct. Simple algorithm of the fundamental frequency for multilayer antisymmetric and arbitrary laminated plates under various boundary conditions is studied by a series of typical examples. From the perspective of coupling, when the number of laminated plates layers N〉8-10, some coupling influence on the fundamental frequency can be neglected. It is reasonable to use specialty orthotropic laminated plates with the same thickness but less layers to calculate the corresponding fundamental frequency of laminated plates. Several examples are conducted to prove correctness of this conclusion. At the end of this paper, the influence of the selected number of layers of specialty orthotropic laminates on the fundamental frequency is investigated. The accuracy and complexity are determined by the number of layers. It is necessary to use proper number of layers of special orthotropic laminates with the same thickness to simulate the fundamental frequency in different boundary conditions.

Mapping analysis of vibrating fundamental frequency for simple-supported elastic rectangle-plates with concentrated mass

By conformal mapping theory, a trigonometric interpolation method between odd and even sequences in rectangle boundary region was provided, and the conformal mapping function of rectangle-plate with arc radius between complicated region and unite dish region was carried out. Aiming at calculating the vibrating fundamental frequency of special-shaped, elastic simple-supported rectangle-plates, in the in-plane state of constant stress, the vibration function of this complicated plate was depicted by unit dish region. The coefficient of ftmdamental frequency was calculated. Whilst, taking simple-supported elastic rectangle-plates with arc radius as an example, the effects on fundamental frequency caused by the concentrated mass and position, the ratio of the length to width of rectangle, as well as the coefficient of constant in-plane stress were analyzed respectively.

Dynamic quasi-continuum model for plate-type nano-materials and analysis of fundamental frequency

A dynamic quasi-continuum model is presented to analyze free vibration of plate-type cubic crystal nano-materials.According to the Hamilton principle,fundamental governing equations in terms of displacement components and angles of rotations are given.As an application of the model,the cylindrical bending deformation of the structure fixed at two ends is analyzed,and a theoretical formula evaluating the fundamental frequency is obtained by using Galerkin's method.Meanwhile,the solution for the classical continuous plate model is also derived,and the size-dependent elastic modulus and Poisson's ratio are taken in computation.The frequencies corresponding to different atomic layers are numerically presented for the plate-type NaC l nano-materials.Furthermore,a molecular dynamics(MD)simulation is conducted with the code LAMMPS.The comparison shows that the present quasi-continuum model is valid,and it may be used as an alternative model,which reflects scale effects in analyzing dynamic behaviors of such plate-type nano-materials.

Characterization of Pathologic Cries of Newborns Based on Fundamental Frequency Estimation

The majority of the sick babies seem in good health at birth and early diagnosis of the various pathologies that can afflict newborn is crucial. For this reason we introduce in this paper the use of the fundamental frequency and the different modes of cries as Hyper-phonation, phonation and high pitched cries to differentiate the pathological cries from the cries of the healthy babies. The automatic estimation of these characteristics enabled us to establish a quantitative characterization of healthy newborn cries and pathologic newborn cries. The results obtained agree with the spectrographic analysis carried out on the healthy and pathologic cries of the newborns.

THE APPLICATION OF WEINSTEIN-CHIEN′S METHOD——THE UPPER AND LOWER LIMITS OF FUNDAMENTAL FREQUENCY OF RECTANGULAR PLATES WITH EDGES ARE THE MIXTURE OF SIMPLY SUPPORTED PORTIONS AND CLAMPED PORTIONS

In this paper, the method of relaxed boundary conditions is applied to rectangular plates with edges which are a sort of the mixture of simply supported portions and clamped portions, so that the lower limit of fundamental frequency of such plates is evaluated. A kind of polynomial satisfying the displacement boundary conditions is designed, os that it is enabled to evaluate the upper limit of fundamental frequency by Ritz' method. The practical calculation examples solved by these methods have given satisfactory results. At the end of this paper, it is pointed out that the socalled exact solution of such plates usually evaluated by the force superposition method is essentially a kind of lower limit of solution, if the truncated error of series which occurs in actual calculation is considered.

Reliability Based Optimization of Composite Laminates for Frequency Constraint

The reliability based optimization （RBO） issue of composite laminates trader fundamental frequency constraint is studied. Considering the tmcertainties of material properties, the frequency constraint reliability of the structure is evaluated by the combination of response surface method （RSM） and finite element method. An optimization algorithm is developed based on the mechanism of laminate frequency characteristics, to optimize the laminate in terms of the ply amount and orientation angles. Numerical examples of composite laminates and cylindrical shell illustrate the advantages of the present optimization algorithm on the efficiency and applicability respects. The optimal solutions of RBO are obviously different from the deterministic optimization results, and the necessity of considering material property uncertainties in the composite structural frequency constraint optimization is revealed.

Geometrical Dimensional Effect on Natural Frequency of Single Layer Graphene in Armchair Configuration

Graphene has remarkable strength,such as yield strength and elastic constant.The dynamic behaviour of graphene sheet is affected by geometrical variation in atomic arrangement.This paper introduced graphene with armchair atomic structure for estimating fundamental natural frequencies.The presented analysis can be useful for the possible high frequency nanomechanical resonator systems.The analytical formulation,based on classical plate theory and continuum solid modelling based finite element method have been performed for estimation of fundamental natural frequencies of single layer graphene sheet(SGLS)with different boundary conditions.The free edge and clamped edge boundary conditions have been considered.For simplifying analytical formulations,Blevins approach for dynamic solution has been adopted and for validating analytical results.The finite element analysis of SLGS has been performed using ANSYS software.The effect of variation in geometrical parameters in terms of width and length of SLGS has been analysed for realization of ultra-high frequency based nanomechanical resonator systems.

Normalized estimation of fundamental frequency and measurement of harmonics/interharmonics

An adaptive notch filter is presented to estimate the fundamental frequency and measure both harmonics and interharmonics of an almost periodic signal with unknown time-variant fundamental frequency, which has the ro- bustness that the convergence speed is determined by neither amplitude nor frequency of fundamental component. The algorithm forms a one-dimensional slow adaptive integral manifold whose existence and stability are proved by averaging method and Lyapunov stability theorem. The local exponential stability and the ultimate boundedness of fundamental fre- quency estimation are proved. The local exponential stability makes sure that the fundamental frequency, the harmonic and interharmonic components can be all fast tracked. The principle for adjusting the parameters with their influences on tran- sient and steady-state performance is investigated and decreasing parameters can improve noise characteristic. The validity is verified by simulation results.

Fundamental Frequency Statistics for Young Male Speakers of Mandarin

In forensic speaker comparison(FSC),it is essential not only to evaluate the similarity between two(or more)samples,but also the typicality of the features in the relevant population.For the typicality,it is necessary that the population statistics related to the phonetic parameters be available.This article presents the statistics for the fundamental frequency(F0)of 100 young Chinese male speakers producing both reading and spontaneous speech.Five descriptive statistics of long‑term F0,namely mean,median,mode,standard deviation(SD),and coefficient of variation(CV=SD/mean),are shown in histograms and scatter diagrams.Results show that the distributions of the five statistics are near normal.The findings are compared with the literature and discussed with respect to forensic phonetic implications.This article concludes that the results for the F0 statistics in the present study can be used in FSC casework as reference data on F0 for the young male Chinese population.

Estimating mean trabecular bone spacing based on the combination of Hilbert transform and fundamental frequency estimation

Ultrasonic backscatter signals from cancellous bone are sensitive to the microstructure of trabecular bone,and thus enable the feasibility to extract microstructural information of trabecular bone.The mean trabecular bone spacing(MTBS)is an important parameter for characterizing bone microstructure.This paper proposes an MTBS estimation method based on the combination of Hilbert transform and fundamental frequency estimation(CHF). The CHF was verified with ultrasonic backscatter signals from simulations and in vitro measurements at a central frequency of 5MHz.The CHF method was compared with the simplified inverse filter tracking(SIFT)method,Simons' Quadratic Transformation(QT)method,Singular Spectrum Analysis(SSA)method,and Spectral Autocorrelation(SAC)method.Monte-Carlo simulations were performed by varying the MTBS,signal-to-noise ratio(SNR),standard deviation of regular spacing(SDRS),amplitude ratio of diffuse scattering to regular scattering(Ad)and frequency dependent attenuation(nBUA).The simulation results showed that the CHF method had a better performance in MTBS estimation under almost all the examination conditions except for SNR.The estimation percentage correct(EPC)was greater than 90% when the MTBS was in the range of 0.4to 1.4mm.In the in vitro measurements,the estimated EPC by the CHF method was91.25±7.81%(mean±standard deviation).A significant correlation was observed for the CHF-estimated MTBS and micro-computed tomography(μ-CT)-measured values(R^2=0.75,p<0.01).These results demonstrate that the CHF method is anti-interference for MTBS estimation and can be used to estimate trabecular bone spacing.

SOTEM野外数据采集中的关键参数分析

电性源短偏移距瞬变电磁法(SOTEM)在野外数据采集中涉及诸多参数,它们的选择与实测数据的信号质量、探测灵敏度等密切相关。本文依据中国地球物理学会团体标准《电性源短偏移距瞬变电磁法勘探技术规程》(T/CGS 002—2021)中的相关规定,并结合一些数值模拟和实际案例,对发射源长度、发射基频、偏移距、装置类型、观测分量等关键参数的选取依据进行了分析与阐述,获得的相关认识对指导SOTEM野外施工、发挥SOTEM探测性能具有重要意义。

大规模光伏经柔直送出系统的近工频耦合振荡机理与特性分析

针对近工频耦合振荡这类新型振荡稳定性问题,研究了其发生机理和稳定特性。建立大规模光伏经柔直送出系统的全电磁暂态模型,仿真展示了近工频耦合振荡的发生条件。通过分析设备在振荡频率下的复功率分布,阐明系统振荡源头与传播特性。基于在线阻抗分析研究振荡发生的电路机理,分析影响振荡稳定性的关键因素。结果表明,在次/超同步近工频段,光伏电站表现为电阻为负的容性元件,与柔直送端换流站、输电线路共同构成负阻尼的串联谐振电路,从而引发不稳定的近工频耦合振荡;光伏网侧换流器、柔直换流器控制参数和输电线路电抗等因素会影响系统的稳定性。

球体质量块型六维加速度传感器的最大工作频率

工作频带是加速度传感器的重要性能指标之一,但六维加速度传感器的最大工作频率目前尚不明确。鉴于此,分别以实心球体质量块型和空心球体质量块型六维加速度传感器为研究对象,构建了系统最大工作频率的数学模型。首先,通过虚拟实验,获得了传感器基频及最大工作频率与质量块直径和支链刚度之间的数据对。接着,分别绘制了基频和最大工作频率的性能图谱,并运用多元线性回归理论拟合了数据对。最后,运用线性包络原理建立了2个频率之间的映射关系。结果表明,最大工作频率始终介于基频的1/35~1/30区间内。

悬索桥基频影响因素的参数化分析与实用计算

桥梁设计师常常采用简化(实用)公式估算桥梁基频,用以在大跨桥梁设计的前期阶段估算其动力性能。但是随着桥梁建设的发展,部分公式的精度已无法满足要求;在实际使用时各公式易用性也存在较大差异。本文在分析各基频估算公式误差来源的基础上,选择关键变量、采用参数化有限元模型分析各控制因素的影响效应,据此选择改进策略,同时在分析各参数相互关系的基础上进行变量精简,提升估算公式的易用性。经实测和计算基频值的验证,改进实用计算公式在提高了易用性和适用性的同时,有效控制了基频估算结果的整体误差极值,提升了基频估算公式的工程应用价值。

基于蒙特卡洛法的Euler-Bernoulli梁基频和振型求解方法

将Rayleigh法和蒙特卡洛法相结合,在Euler-Bernoulli梁理论假设下求解了均匀梁、变截面梁和附带集中质量的变截面梁自由振动问题.对原本连续的梁结构模型进行离散化处理,利用蒙特卡洛法给出梁结构的假设振型.将假设得到的梁结构振型函数代入Rayleigh法,多次计算过程中,将历次基频所得值与计算所得最小值进行比较,根据其相对误差判断是否满足收敛条件,进而求得基频及对应的振型.结果表明,不同计算模型中基频最大误差不超过10%,能够满足工程需求,且精度和时间的控制参数调整灵活,使用者可根据自身需要自行调节.该方法理论简明,适用范围广泛,能够快速准确地求解诸多类型的梁结构基频和振型.