• Title, Summary, Keyword: Fundamental Frequency

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Estimation of Fundamental Frequency Using an Instantaneous Frequency Based on the Symmetric Higher Order Differential Energy Operator (대칭구조를 갖는 일반적인 고차의 미분 에너지함수를 기반한 순간주파수를 이용한 음성의 기본주파수 추정)

  • Iem, Byeong-Gwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.12
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    • pp.2374-2379
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    • 2011
  • The fundamental frequency of the voiced speech is estimated using the instantaneous frequency based on the symmetric higher order differential energy operator. The instantaneous frequency based on the symmetric higher order energy operator shows better frequency estimation result since it is aligned to the time instance of the signal. The speech is pre-processed by a lowpass filter to remove higher frequency components. Then, it is processed by the instantaneous frequency to obtain the fundamental frequency estimates. The symmetric higher order energy operator has been used as an indicator to determine the voiced/unvoiced speech. The fundamental frequency estimates are further processed by a moving average filter to obtain the monotonically changed estimates. The obtained fundamental frequency estimates have been compared with the spectrogram of the speech to confirm its accuracy.

Fundamental Frequency Estimation based on Time-Frequency Analysis (시주파수 분석법을 이용한 음성의 기본주파수 검출)

  • Iem Byeong-Gwan
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.1
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    • pp.31-34
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    • 2006
  • A simple robust fundamental frequency estimator on the time-frequency domain is proposed. Combined with the appropriately designed low-pass filter, the instantaneous frequency estimator based on the Teager-Kaiser energy function can detect the fundamental frequency of speech signal. The Teager-Kaiser function can be obtained through real computation and show the change of frequency as time goes. And when a speech block with N samples is processed with a lowpass fille. with length of L, it requires $O(N{\cdot}(L+5))operations,$ compared to $O(N{\cdot}2log_2N+L))operations$ in the recently introduced wavelet and conventional instantaneous frequency method. The computer simulation confirms the usefulness of the proposed fundamental frequency estimation method.

Gender Classification Using Open Quotient and Fundamental Frequency (Open Quotient와 Fundamental Frequency 정보를 이용한 성 별 분류)

  • Kim, Hye-Jin;Yoon, Young-woo;Yoon, Ho-sub;Lee, Jae-Yeon
    • Proceedings of the Korea Information Processing Society Conference
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    • pp.319-320
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    • 2009
  • 본 논문은 Open Quotient 정보와 Fundamental Frequency 정보를 이용한 성별 분류에 관한 것이다. 기존의 대표적인 성별 분류 특징정보로 Fundamental Frequency가 있으나, Fundamental Frequency 정보로는 이용하여 분류하는 데에 중점을 두어왔으나 이 정보는 노인 혹은 어린이에 대해서는 성별 분류 특징이 어렵다는 단점이 있었다. 한편 본 논문에서 제안하는 방법은 Open Quotient와 Fundamental Frequency의 연령대에 따른 차별 정보를 이용하여 학습시켜 성별분류를 보다 나은 성능으로 분류할 수 있다.

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An Analytic Method for Measuring Accurate Fundamental Frequency Components (기본파 성분의 정확한 측정을 위한 해석적 방법)

  • Nam, Sun-Yeol;Gang, Sang-Hui;Park, Jong-Geun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.4
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    • pp.175-182
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    • 2002
  • This paper proposes an analytic method for measuring the accurate fundamental frequency component of a fault current signal distorted with a DC-offset, a characteristic frequency component, and harmonics. The proposed algorithm is composed of four stages: sine filer, linear filter, Prony's method, and measurement. The sine filter and the linear filter eliminate harmonics and the fundamental frequency component, respectively. Then Prony's method is used to estimate the parameters of the DC-offset and the characteristic frequency component. Finally, the fundamental frequency component is measured by compensating the sine-filtered signal with the estimated parameters. The performance evaluation of the proposed method is presented for a-phase to around faults on a 345 kV 200 km overhead transmission line. The EMTP is used to generate fault current signals under different fault locations and fault inception angles. It is shown that the analytic method accurately measures the fundamental frequency component regardless of the characteristic frequency component as well as the DC-offset.

A Research on Time-Dependent Fundamental Frequency Variations after Waking up in the Morning (기상 후 시간에 따른 음도 변화에 대한 연구)

  • Ahn, Jong-Bok;Nam, Hyun-Wook;Jeong, Ok-Ran
    • Speech Sciences
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    • v.15 no.2
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    • pp.169-176
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    • 2008
  • This study was intended to analyze difference of vocal folds movements between upon wakeup and in several hours later in the morning. The difference of vocal fold movements was compared with fundamental frequency and a range of fundamental frequencies from maximum to minimum. The participants were 30 female adults between 20 and 29 years old. Voice samples were collected from their reading sentence (Jeong, 1993). The first sampling was conducted within 5 minutes after wakeup, while the second on 1 hour after the first sampling. Finally, the third voice sample was collected on 6 hours after the second sampling. The results of this study were as follows: First, fundamental frequency of the participants were by hour significantly time-dependent(F=7.843). Post-hoc multiple comparison (LSD) was conducted to determine when the difference could be observed. The result showed significant differences between upon wakeup and 6 hours later (p< .001) and between 1 hour later and 6 hours later (p< .05). Second, there were a significantly time-dependent ranges of fundamental frequencies of participants by hour (F=3.130). According to the results of the LSD analysis the significant differences in range of fundamental frequencies were found between upon wakeup and 1 hour later and also between wakeup and 6 hours later (p< .05). The results above indicate that vocal fold movements upon wakeup is different from those of several hours later.

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Voice transformation for HTS using correlation between fundamental frequency and vocal tract length (기본주파수와 성도길이의 상관관계를 이용한 HTS 음성합성기에서의 목소리 변환)

  • Yoo, Hyogeun;Kim, Younggwan;Suh, Youngjoo;Kim, Hoirin
    • Phonetics and Speech Sciences
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    • v.9 no.1
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    • pp.41-47
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    • 2017
  • The main advantage of the statistical parametric speech synthesis is its flexibility in changing voice characteristics. A personalized text-to-speech(TTS) system can be implemented by combining a speech synthesis system and a voice transformation system, and it is widely used in many application areas. It is known that the fundamental frequency and the spectral envelope of speech signal can be independently modified to convert the voice characteristics. Also it is important to maintain naturalness of the transformed speech. In this paper, a speech synthesis system based on Hidden Markov Model(HMM-based speech synthesis, HTS) using the STRAIGHT vocoder is constructed and voice transformation is conducted by modifying the fundamental frequency and spectral envelope. The fundamental frequency is transformed in a scaling method, and the spectral envelope is transformed through frequency warping method to control the speaker's vocal tract length. In particular, this study proposes a voice transformation method using the correlation between fundamental frequency and vocal tract length. Subjective evaluations were conducted to assess preference and mean opinion scores(MOS) for naturalness of synthetic speech. Experimental results showed that the proposed voice transformation method achieved higher preference than baseline systems while maintaining the naturalness of the speech quality.

Topology Optimization of Plane Structures using Modal Strain Energy for Fundamental Frequency Maximization

  • Lee, Sang-Jin;Bae, Jung-Eun
    • Architectural research
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    • v.12 no.1
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    • pp.39-47
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    • 2010
  • This paper describes a topology optimization technique which can maximize the fundamental frequency of the structures. The fundamental frequency maximization is achieved by means of the minimization of modal strain energy as an inverse problem so that the strain energy based resizing algorithm is directly used in this study. The strain energy to be minimized is therefore employed as the objective function and the initial volume of structures is used as the constraint function. Multi-frequency problem is considered by the introduction of the weight which is used to combine several target modal strain energy terms into one scalar objective function. Several numerical examples are presented to investigate the performance of the proposed topology optimization technique. From numerical tests, it is found to be that the proposed optimization technique is extremely effective to maximize the fundamental frequency of structure and can successfully consider the multi-frequency problems in the topology optimization process.

Optimum Thickness Distributions of Plate Structure with Different Essential Boundary Conditions in the Fundamental Frequency Maximization Problem (기본고유진동수 최대화 문제에 있어서 경계조건에 따른 판구조물의 최적두께 분포)

  • Lee, Sang-Jin;Kim, Ha-Ryong
    • Proceeding of KASS Symposium
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    • pp.227-232
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    • 2006
  • This paper investigate the optimum thickness distribution of plate structure with different essential boundary conditions in the fundamental natural frequency maximization problem. In this study, the fundamental natural frequency is considered as the objective function to be maximized and the initial volume of structures is used as the constraint function. The computer-aided geometric design (CAGD) such as Coon's patch representation is used to represent the thickness distribution of plates. A reliable degenerated shell finite element is adopted calculate the accurate fundamental natural frequency of the plates. Robust optimization algorithms implemented in the optimizer DoT are adopted to search optimum thickness values during the optimization iteration. Finally, the optimum thickness distribution with respect to different boundary condition

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The Comparison of Fundamental Frequencies of Children with Different Hearing Level (청력수준에 따른 초등학교 아동의 기본주파수 비교)

  • Yoon Misun
    • MALSORI
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    • no.52
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    • pp.49-60
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    • 2004
  • The purpose of this paper was to evaluate the effect of hearing level on fundamental frequencies in children. Participants totaled sixty children divided by three groups: congenitally deafened children with cochlear implantation(CI), congenitally deafened children with hearing aids(HA), and children with normal hearing(NH). Fundamental frequencies were measured during the sustained phonation of a vowel /a/. There was statistically significant difference of fundamental frequencies across the groups(p<.01). In post hoc analysis, HA and NH group showed statistically significant difference, but CI group didn't showed significant differences with two groups. In correlation analysis between F0 and the chronological age, there were significant negative tendencies in CI and NH group, but not in HA group. The characteristics of fundamental frequency in CI group were found similar to NH group than HA group in this study. Therefore the results of this study suggest that the hearing level is one of the influencing factors to the fundamental frequency of children.

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Fundamental vibration frequency prediction of historical masonry bridges

  • Onat, Onur
    • Structural Engineering and Mechanics
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    • v.69 no.2
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    • pp.155-162
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    • 2019
  • It is very common to find an empirical formulation in an earthquake design code to calculate fundamental vibration period of a structural system. Fundamental vibration period or frequency is a key parameter to provide adequate information pertinent to dynamic characteristics and performance assessment of a structure. This parameter enables to assess seismic demand of a structure. It is possible to find an empirical formulation related to reinforced concrete structures, masonry towers and slender masonry structures. Calculated natural vibration frequencies suggested by empirical formulation in the literatures has not suits in a high accuracy to the case of rest of the historical masonry bridges due to different construction techniques and wide variety of material properties. For the listed reasons, estimation of fundamental frequency gets harder. This paper aims to present an empirical formulation through Mean Square Error study to find ambient vibration frequency of historical masonry bridges by using a non-linear regression model. For this purpose, a series of data collected from literature especially focused on the finite element models of historical masonry bridges modelled in a full scale to get first global natural frequency, unit weight and elasticity modulus of used dominant material based on homogenization approach, length, height and width of the masonry bridge and main span length were considered to predict natural vibration frequency. An empirical formulation is proposed with 81% accuracy. Also, this study draw attention that this accuracy decreases to 35%, if the modulus of elasticity and unit weight are ignored.