Yu-Cheng Liu
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Yu-Cheng Liu has a total of 10 co-authors. Here are the top co-authors by number of shared publications:
- Jin Huang Huang
Department of Mechanical Engineering, Feng Chia University, 100 Wen Hwa Road, Taichung 40745, Taiwan
2 shared publications - Chen-Hung Huang
Department of Aerospace and Systems Engineering, Feng Chia University, Taichung City, TAIWAN
1 shared publication - Dane-Jong Yang
Department of Mechanical and Computer-Aided Engineering, Feng Chia University, No. 100 Wenhwa Road, Seatwen, Taichung 40724, Taiwan
1 shared publication - H. Dang-Trung
Division of Computational Mathematics and Engineering, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam; Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City 700000, Vietnam; Department of Mathematics, University of Bergen, Bergen 5020, Norway
1 shared publication Jin Huang Huang
Feng Chia University
1 shared publicationMin Hon Tsai
Feng Chia University
1 shared publication
Latest Publications
- Open Access
Under-Balcony Acoustic Diagnosis Using FOA-Based Directional Metrics: Early–Late Entropy and Vertical-Energy Discrepancy at 125 Hz, 1 kHz, and 4 kHz
Traditional concert-hall evaluations primarily rely on ISO 3382-1 scalar parameters (e.g., C50 and C80), which summarize temporal energy behavior but provide limited insight into the directional composition of early reflections, particularly in geometrically shadowed seating zones. This paper presents a first-order Ambisonics (FOA)-based 3D acoustic sensing framework to diagnose under-balcony directional imbalance, with emphasis on early vertical-reflection deficiency. Scene-based FOA impulse responses (WXYZ) were measured at 11 audience positions (P1–P11) in the National Concert Hall (Taipei) and analyzed using intensity-based direction-of-arrival (DoA) proxies, axis-resolved directional energy build-up, and a distributional descriptor based on directional spatial entropy. Results are presented at three representative frequencies (125 Hz, 1 kHz, and 4 kHz) and analyzed within full (0–200 ms), early (0–80 ms), and late (80–200 ms) windows. While the magnitude proxy exhibits strong seat-to-seat variability and does not support a uniform attenuation assumption under the balcony, direction-resolved metrics reveal a consistent under-balcony signature. Specifically, the early–late vertical energy discrepancy is persistently negative at under-balcony positions (P7–P11) across all three frequencies, indicating a selective reduction in early vertical contribution relative to the late field. Directional entropy analysis further shows predominantly negative , with more negative values in the under-balcony group, consistent with stronger early directional constraint in shadowed seats. Spatial trend maps are provided via Gaussian RBF interpolation within the audience domain for visualization only. The proposed FOA-based diagnostic framework provides a practical and physically interpretable approach to identify direction-specific early-reflection deficits that remain masked in conventional scalar evaluations, supporting mechanism-oriented assessment and targeted intervention in geometrically constrained listening areas.Open AccessUnder-Balcony Acoustic Diagnosis Using FOA-Based Directional Metrics: Early–Late Entropy and Vertical-Energy Discrepancy at 125 Hz, 1 kHz, and 4 kHz
Traditional concert-hall evaluations primarily rely on ISO 3382-1 scalar parameters (e.g., C50 and C80), which summarize temporal energy behavior but provide limited insight into the directional composition of early reflections, particularly in geometrically shadowed seating zones. This paper presents a first-order Ambisonics (FOA)-based 3D acoustic sensing framework to diagnose under-balcony directional imbalance, with emphasis on early vertical-reflection deficiency. Scene-based FOA impulse responses (WXYZ) were measured at 11 audience positions (P1–P11) in the National Concert Hall (Taipei) and analyzed using intensity-based direction-of-arrival (DoA) proxies, axis-resolved directional energy build-up, and a distributional descriptor based on directional spatial entropy. Results are presented at three representative frequencies (125 Hz, 1 kHz, and 4 kHz) and analyzed within full (0–200 ms), early (0–80 ms), and late (80–200 ms) windows. While the magnitude proxy exhibits strong seat-to-seat variability and does not support a uniform attenuation assumption under the balcony, direction-resolved metrics reveal a consistent under-balcony signature. Specifically, the early–late vertical energy discrepancy is persistently negative at under-balcony positions (P7–P11) across all three frequencies, indicating a selective reduction in early vertical contribution relative to the late field. Directional entropy analysis further shows predominantly negative , with more negative values in the under-balcony group, consistent with stronger early directional constraint in shadowed seats. Spatial trend maps are provided via Gaussian RBF interpolation within the audience domain for visualization only. The proposed FOA-based diagnostic framework provides a practical and physically interpretable approach to identify direction-specific early-reflection deficits that remain masked in conventional scalar evaluations, supporting mechanism-oriented assessment and targeted intervention in geometrically constrained listening areas. - 25 September 2024
- Published by Elsevier in Applied Acoustics
- Vol. 228
Study on the predictions of acoustic characteristics of microspeakers based on the specific airflow resistance of ventilation materials: Mesh type
- 25 September 2024
- Published by Elsevier in Applied Acoustics
- Vol. 228
Study on the predictions of acoustic characteristics of microspeakers based on the specific airflow resistance of ventilation materials: Mesh type
- Open Access
- 27 August 2022
- Published by MDPI AG in Applied Sciences
- Vol. 12 (17) , 8588
Inverse Determination of Acoustic Properties of Acoustic Ventilation Cloth (Woven and Non-Woven) by Particle Swarm Optimization and Estimation of Its Effect on the Frequency Response of the Microspeaker
In this work, microspeaker frequency response was determined based on measurement and simulation. The vents after the rear chamber of the microspeaker were covered with ventilation cloths. Two types of ventilation cloths (acoustic cloths) are commonly used in electroacoustic products, non-woven and woven. Non-woven cloths (5 nos.) consist of irregular meshes and woven cloths (5 nos.) consist of regular meshes. The equivalent circuit model of the microspeaker was formulated by considering five types each of non-woven and woven ventilation cloths. The acoustic properties of the ventilation cloths were estimated from the measured frequency response of the microspeaker and by subsequent use of particle swarm optimization algorithm. Estimated value of the acoustic impedances of the ventilation cloths were used in an equivalent circuit model of the microspeaker for the simulated frequency responses and subsequently compared with the anechoic chamber measurements. Based on the results, the equivalent circuit adequately simulated the measured frequency response of the microspeaker and the estimations of the acoustic impedances of the ventilation cloths were in good agreement with the measured frequency responses of the microspeaker.
- 27 August 2022
- Published by MDPI AG in Applied Sciences
- Vol. 12 (17) , 8588
Open AccessInverse Determination of Acoustic Properties of Acoustic Ventilation Cloth (Woven and Non-Woven) by Particle Swarm Optimization and Estimation of Its Effect on the Frequency Response of the Microspeaker
In this work, microspeaker frequency response was determined based on measurement and simulation. The vents after the rear chamber of the microspeaker were covered with ventilation cloths. Two types of ventilation cloths (acoustic cloths) are commonly used in electroacoustic products, non-woven and woven. Non-woven cloths (5 nos.) consist of irregular meshes and woven cloths (5 nos.) consist of regular meshes. The equivalent circuit model of the microspeaker was formulated by considering five types each of non-woven and woven ventilation cloths. The acoustic properties of the ventilation cloths were estimated from the measured frequency response of the microspeaker and by subsequent use of particle swarm optimization algorithm. Estimated value of the acoustic impedances of the ventilation cloths were used in an equivalent circuit model of the microspeaker for the simulated frequency responses and subsequently compared with the anechoic chamber measurements. Based on the results, the equivalent circuit adequately simulated the measured frequency response of the microspeaker and the estimations of the acoustic impedances of the ventilation cloths were in good agreement with the measured frequency responses of the microspeaker.
- 19 November 2018
- Published by Wiley in Journal of Computing and Information Science in Engineering
- Vol. 19 (1)
Improvements in Shear Locking and Spurious Zero Energy Modes Using Chebyshev Finite Element Method
In this paper, the authors present Chebyshev finite element (CFE) method for the analysis of Reissner–Mindlin (RM) plates and shells. Chebyshev polynomials are a sequence of orthogonal polynomials that are defined recursively. The values of the polynomials belong to the interval [−1,1] and vanish at the Gauss points (GPs). Therefore, high-order shape functions, which satisfy the interpolation condition at the points, can be performed with Chebyshev polynomials. Full gauss quadrature rule was used for stiffness matrix, mass matrix and load vector calculations. Static and free vibration analyses of thick and thin plates and shells of different shapes subjected to different boundary conditions were conducted. Both regular and irregular meshes were considered. The results showed that by increasing the order of the shape functions, CFE automatically overcomes shear locking without the formation of spurious zero energy modes. Moreover, the results of CFE are in close agreement with the exact solutions even for coarse and irregular meshes.
- 19 November 2018
- Published by Wiley in Journal of Computing and Information Science in Engineering
- Vol. 19 (1)
Improvements in Shear Locking and Spurious Zero Energy Modes Using Chebyshev Finite Element Method
In this paper, the authors present Chebyshev finite element (CFE) method for the analysis of Reissner–Mindlin (RM) plates and shells. Chebyshev polynomials are a sequence of orthogonal polynomials that are defined recursively. The values of the polynomials belong to the interval [−1,1] and vanish at the Gauss points (GPs). Therefore, high-order shape functions, which satisfy the interpolation condition at the points, can be performed with Chebyshev polynomials. Full gauss quadrature rule was used for stiffness matrix, mass matrix and load vector calculations. Static and free vibration analyses of thick and thin plates and shells of different shapes subjected to different boundary conditions were conducted. Both regular and irregular meshes were considered. The results showed that by increasing the order of the shape functions, CFE automatically overcomes shear locking without the formation of spurious zero energy modes. Moreover, the results of CFE are in close agreement with the exact solutions even for coarse and irregular meshes.
- 1 June 2014
- Published by Trans Tech Publications, Ltd. in Advanced Materials Research
- Vol. 936, 1994-1998
Evaluation of Sound Absorption Capability from PET Mesh to PET/PU Composite Board
This article completely investigates from nonwoven to PET/PU composite board on the variations of absorption coefficient by using standard impedance tube with four microphones. Recently, PET/PU composite board is becoming a popular and functional material because of the high flexibility in the abilities, such as thermal protection, chemical-proof, acoustic-resistance and etc.. Thus, it is important to realize the variations of absorption capability from single material to complete composite material, and can feedback some suggestions to the designer. Results shows that nonwoven only has a stable increase in absorption coefficient with the frequencies because of the inherent porous characteristics. With the substantial properties, foam has lower absorption coefficient and two peaks occurring in the higher frequencies. These both peaks are caused by the resonance between wave and foam at specified frequency. With an additional nonwoven in the rear side of composite foam, absorption coefficient of PET/PU composite board will effectively increase. Based on the diverse applications, absorption coefficient of PET/PU composite board can be flexible modulated to consistent with the requirements.
- 1 June 2014
- Published by Trans Tech Publications, Ltd. in Advanced Materials Research
- Vol. 936, 1994-1998
Evaluation of Sound Absorption Capability from PET Mesh to PET/PU Composite Board
This article completely investigates from nonwoven to PET/PU composite board on the variations of absorption coefficient by using standard impedance tube with four microphones. Recently, PET/PU composite board is becoming a popular and functional material because of the high flexibility in the abilities, such as thermal protection, chemical-proof, acoustic-resistance and etc.. Thus, it is important to realize the variations of absorption capability from single material to complete composite material, and can feedback some suggestions to the designer. Results shows that nonwoven only has a stable increase in absorption coefficient with the frequencies because of the inherent porous characteristics. With the substantial properties, foam has lower absorption coefficient and two peaks occurring in the higher frequencies. These both peaks are caused by the resonance between wave and foam at specified frequency. With an additional nonwoven in the rear side of composite foam, absorption coefficient of PET/PU composite board will effectively increase. Based on the diverse applications, absorption coefficient of PET/PU composite board can be flexible modulated to consistent with the requirements.
- 1 August 2006
- Published by American Society of Civil Engineers (ASCE) in Journal of Engineering Mechanics
- Vol. 132 (8) , 889-897
Electroelastic Response of a Laminated Composite Plate with Piezoelectric Sensors and Actuators
The paper deals with the fully coupled response characteristics of a multilayered composite plate with piezoelectric layers. The response quantities of the plate are coupled by the mechanical field and the electric field. Based on the three-dimensional linear piezoelectricity and the first-order shear deformation theory, the fundamental unknowns, such as the displacements and the electric potential, are assumed to be expandable through the plate thickness coordinate. The governing equations of motion of the plate are presented in terms of the unknown displacement and electrical potential coefficients. When the boundary conditions and electromechanical inputs are specified, the double Fourier series is used to obtain the response of the simply supported multilayered plates. Numerical results for the static and dynamic response of the laminated composite plates with different lamination schemes and having a PIC-151 piezoelectric material layer are obtained. The effects of the plate thinness ratio, plate aspect ratio, lamination scheme, fiber orientations, and piezoelectric coupling on the static and dynamic response are presented.
- 1 August 2006
- Published by American Society of Civil Engineers (ASCE) in Journal of Engineering Mechanics
- Vol. 132 (8) , 889-897
Electroelastic Response of a Laminated Composite Plate with Piezoelectric Sensors and Actuators
The paper deals with the fully coupled response characteristics of a multilayered composite plate with piezoelectric layers. The response quantities of the plate are coupled by the mechanical field and the electric field. Based on the three-dimensional linear piezoelectricity and the first-order shear deformation theory, the fundamental unknowns, such as the displacements and the electric potential, are assumed to be expandable through the plate thickness coordinate. The governing equations of motion of the plate are presented in terms of the unknown displacement and electrical potential coefficients. When the boundary conditions and electromechanical inputs are specified, the double Fourier series is used to obtain the response of the simply supported multilayered plates. Numerical results for the static and dynamic response of the laminated composite plates with different lamination schemes and having a PIC-151 piezoelectric material layer are obtained. The effects of the plate thinness ratio, plate aspect ratio, lamination scheme, fiber orientations, and piezoelectric coupling on the static and dynamic response are presented.