Computer Simulation of the Quality of Sound Propagating through Different Acoustic Media

2006 ◽  
Author(s):  
Lianqiu Liu ◽  
Bing Cui ◽  
J. Yu
Keyword(s):  
Computer Simulation ◽  
Acoustic Media

Numerical Analysis of the Acoustical Quality of a Multi-Purpose Hall

1995 ◽  
Vol 2 (3) ◽  
pp. 487-500 ◽  
Author(s):  
X.W. Meng ◽  
G. De Borger ◽  
M. Van Overmeire
Keyword(s):  
Computer Simulation ◽  
Sound Pressure Level ◽  
Decay Time ◽  
Sound Pressure ◽  
Field Measurements ◽  
Pressure Level ◽  
Energy Fraction ◽  
Experimental Values ◽  
Simulation Package

In this paper, the acoustical features are described of a multi-purpose auditorium of the Free University of Brussels which were investigated both with field measurements and computer simulation. The convergence of the algorithm of the simulation package RAYNOISE was investigated as a function of the influence on the calculated results of the choice of the number of rays and the reflection order. By comparing the numerical and experimental values of the sound pressure level and early decay time, it is demonstrated that sufficiently accurate acoustical models can be developed. Based on these models, acoustical quantities such as the early energy fraction, sound pressure level, early decay time and early lateral energy fraction were calculated and employed to evaluate the acoustical quality of this multi-purpose hall.

Modelling of Scattering from Balcony Fronts

2002 ◽  
Vol 9 (3) ◽  
pp. 219-231
Author(s):  
T. M. Chan ◽  
W. M. To
Keyword(s):  
Computer Simulation ◽  
Ray Tracing ◽  
Diffuse Reflection ◽  
Sound Field ◽  
Direct Wave ◽  
Practice Experience ◽  
Concert Halls ◽  
Distinguished Group ◽  
Opera Houses

Balconies are normally used in large auditoria such as concert halls or opera houses, to increase seating capacity or to give better view for a distinguished group of the audience. When ray-tracing based computer models are applied to study the acoustical quality of these auditoria, the alteration of the sound field due to balcony fronts is normally unobservable, because of the relative small size of the balcony fronts in the auditorium. Furthermore, most diffuse reflection ray-tracing methods are not based on direct wave acoustics but on an approximation of the scattering effect. In practice, experience shows that balcony fronts give additional warmth to music. This effect is more prominent when singers perform in traditional horseshoe shaped opera houses with multi-levels balconies. This paper describes modelling of scattering from balcony fronts using a theoretical wave approach, in which the incident wave front is not plane but spherical. A computer simulation illustrates the scattering of sound that takes place when the wavefront impinges on the surface of the balcony fronts.

scholarly journals Analysis of Various Ventilation Systems Due to the Quality of Indoor Air in Educational Buildings

Proceedings ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 29
Author(s):  
Katarzyna Gładyszewska-Fiedoruk ◽  
Vasyl Zhelykh ◽  
Andrii Pushchinskyi
Keyword(s):  
Carbon Dioxide ◽  
Computer Simulation ◽  
Air Quality ◽  
Knowledge Acquisition ◽  
Indoor Air ◽  
Educational Buildings ◽  
Building Ventilation ◽  
Ventilation Systems

The quality of internal air is one of the factors that affect the pace and quality of knowledge acquisition. Therefore, it is important that the classrooms have high air quality. Using computer simulation, the effect of various building ventilation variants on air quality in classrooms was analyzed. As an indicator of air quality, the concentration of carbon dioxide in school halls was assumed.

Analysis of Contractor Pay Adjustment Schedule Using Simulation

1996 ◽  
Vol 1544 (1) ◽  
pp. 109-115
Author(s):  
Robert P. Elliott ◽  
Yanjun Qiu
Keyword(s):  
Computer Simulation ◽  
Quality Control ◽  
Quality Assurance ◽  
Quality Index ◽  
Direct Analysis ◽  
Detailed Examination ◽  
Construction Contracts ◽  
Simulation Process ◽  
Control Quality

A common provision in quality control/quality assurance construction contracts is the adjustment of the contractor's pay on the basis of the quality of the construction. The expected impact of the provision on the pay should be examined to ensure that the adjustments are neither unduly severe nor excessively lenient. Most pay adjustment plans have been developed around a quality index by using a percent defective approach. Analyses of these plans are complex but reasonably well defined. Other plans, however, are more complex and do not lend themselves to direct analysis. These plans can be examined by computer simulation. The use of computer simulation to examine a complex pay adjustment provision is demonstrated. The analyses show that simulation can reveal that a pay adjustment schedule behaves differently than it appears on the surface. For example, the schedule examined bases pay solely on averages and appears to ignore construction variability. The analyses, however, demonstrate that the pay adjustments are at least as sensitive to construction variability as they are to construction averages. It is also shown that the simulation process can provide a better, more detailed examination of the pay schedule than is possible by simply determining the expected pay. In particular, the simulation process can provide an indication of the variability of pay at various quality levels and can identify the factors most responsible for pay adjustments.

scholarly journals Fabrication Improvement of Cold Forging Hexagonal Nuts by Computational Analysis and Experiment Verification

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Shao-Yi Hsia ◽  
Yu-Tuan Chou
Keyword(s):  
Computer Simulation ◽  
Automobile Industry ◽  
Critical Role ◽  
Simulation Software ◽  
Die Design ◽  
Cold Forging ◽  
Experiment Verification ◽  
Flow Stress Equation ◽  
Deform 3D

Cold forging has played a critical role in fasteners and has been applied to the automobile industry, construction industry, aerospace industry, and living products so that cold forging presents the opportunities for manufacturing more products. By using computer simulation, this study attempts to analyze the process of creating machine parts, such as hexagonal nuts. The DEFORM-3D forming software is applied to analyze the process at various stages in the computer simulation, and the compression test is also used for the flow stress equation in order to compare the differences between the experimental results and the equation that is built into the computer simulation software. At the same time, the metallography and hardness of experiments are utilized to understand the cold forging characteristics of hexagonal nuts. The research results would benefit machinery businesses to realize the forging load and forming conditions at various stages before the fastener formation. In addition to planning proper die design and production, the quality of the produced hexagonal nuts would be more stable to promote industrial competitiveness.

Genetic polymorphism and mixed-stock fisheries analysis

2004 ◽  
Vol 61 (7) ◽  
pp. 1075-1082 ◽  
Author(s):  
Steven T Kalinowski
Keyword(s):  
Computer Simulation ◽  
Genetic Polymorphism ◽  
Estimation Error ◽  
Genetic Data ◽  
Data Sets ◽  
Polymorphic Loci ◽  
Squared Error ◽  
Mixed Stock ◽  
The Relationship

Genetic data can be used to estimate the stock composition of mixed-stock fisheries. Designing efficient strategies for estimating mixture proportions is important, but several aspects of study design remain poorly understood, particularly the relationship between genetic polymorphism and estimation error. In this study, computer simulation was used to investigate how the following variables affect expected squared error of mixture estimates: the number of loci examined, the number of alleles at those loci, and the size of baseline data sets. This work showed that (i) loci with more alleles produced estimates of stock proportions that had a lower expected squared error than less polymorphic loci, (ii) highly polymorphic loci did not require larger samples than less polymorphic loci, and (iii) the total number of independent alleles examined is a reasonable indicator of the quality of estimates of stock proportions.

scholarly journals Simulation of sound transmission through the porous material, determining the parameters of acoustic absorption and sound reduction

2018 ◽  
Vol 157 ◽  
pp. 02058
Author(s):  
Peter Zvolenský ◽  
Juraj Grenčík ◽  
Ľubomír Kašiar ◽  
Vladimír Stuchlý
Keyword(s):  
Computer Simulation ◽  
Structural Design ◽  
Internal Noise ◽  
Acoustic Properties ◽  
Acoustic Absorption ◽  
New Materials ◽  
Acoustic Parameters ◽  
Acoustic Comfort ◽  
Sound Reduction

Currently, the quality of structural design of a railway coach is evaluated by so called acoustic comfort, which is characterized by achieved levels of internal noise. Therefore, acoustic parameters of car body are being developed purposely. The paper presents the results of the computer simulation of noise transmission through the wagon walls and the use of noise tests from the train running. The acoustic properties of the original and new materials in the care body are compared.

Assessing the quality of the sampling of fuel peat using computer simulation

Fuel ◽  
1995 ◽  
Vol 74 (12) ◽  
pp. 1910-1912 ◽  
Author(s):  
Kyösti Huhtala ◽  
Anssi Järvenpää ◽  
Veikko Piirainen ◽  
Jaakko Lehtovaara
Keyword(s):  
Computer Simulation
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