In this study, an experimental analysis of noise reduction in road traffic by applying the Micro Grooving technique to concrete highway pavements is explored. Initiated in 1984 to address the aging and damage issues observed in South Korea's concrete highways, Micro Grooving is known for creating fine grooves on the cement pavement surface to increase friction, prevent hydroplaning, and inhibit ice formation, while reducing vehicle friction noise by 3∼5dB(A). It is determined from noise measurement results that the application of the Micro Grooving method can be expected to reduce roadside noise and enhance the safety of drivers' driving experience.

Most domestic pilots are trained at local airfields using propeller aircraft. Training aircraft are mainly trained in the airspace around the aerodrome, and mainly take-off and landing exercises that require a lot of practice among flight control skills. Aircraft noise is a sound that humans do not want. In this study, based on the Rotax 914 engine used in Korea, the propeller blade angle was changed by 1 degree for the 3-leaf “K company” propeller and the 3-leaf GSC wooden propeller, and the engine RPM was changed to examine the noise and thrust changes. The purpose of this study is to check whether noise and thrust loss are the least at the engine's maximum RPM, and to propose an aircraft operation plan in the noisy aerodrome area based on the values.

A theoretical model has been studied to describe the sound radiation analysis for a railway under the action of harmonic moving line point forces. When a railway is analyzed, it had been modeled as curved beams with distributed springs and dash-pots that represent the radial, tangential stiffness and damping of rail, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The curved beam material and elastic foundation are assumed to be lossless Bernoulli-Euler beam theory including a tension force(T), damping coefficient(C) and stiffness of foundation(κ2) will be employed. The expression for sound power is integrated numerically and the results examined as a function of Mach number(M), wave-number ratio(γ) and stiffness factor(ψ).

Noise is a sound that humans do not want. In this study, noise is measured for C172, the most frequently used general aviation trainer in Korea and abroad. In addition, in this study, noise measurement points are selected for Muan Airport, where most of the domestic training aircraft fly under the supervision of the Ministry of Land, Infrastructure and Transport. Based on this, the measured data is scaled and analyzed. In addition, we intend to analyze what characteristics C172 aircraft have unique through frequency analysis of noise of C172. Through this, it is intended to understand what type of noise training aircraft affect in future studies.

The purpose of this study was to improve the noise measurement method of noise sources and the corresponding noise reduction measures during each manufacturing process closest to the workers in the large and hige power machine. To this end, the noise generated in the large and high power machine was measured and analyzed, and the frequency characteristics of noise sources and the causes of noise were identified. The noise map was used to predict the noise reduction effect. Moreover, it is expected that this will ultimately contribute to the reduction of human risks caused by the noise of the large and high power machine.

The source of wayside noise for the train are the aerodynamic noise, wheel/rail noise, and power unit noise. The major source of railway noise is the wheel/rail noise caused by the interaction between the wheels and rails. The Structure borne noise is mainly a low frequency problem. The train noise and vibration nearby the elevated railway make one specific issue. The microphone array method is used to search sound radiation characteristics of elevated structure to predict the noise propagation from an elevated railway. In this paper, the train noise and structure borne noise by train are measured. From the results, we investigated the effect on the sound absorption tunnel for elevated railway.

In the car speaker, because the sound characteristics is changed by the space of car which mount the speaker, the speaker elements must be decide according to sound field. In this study, the nonlinear characteristics, the frequency response and the sound pressure for the same size speakers which is adapted to domestic car model are investigated. The car model is classified to semi-midsize, midsized, full size automobile in order to change the car space. As a results, we can investigate the differences of the force factor and the stiffness of suspension system for speaker. According to the change of the speaker characteristics, the sound pressure is changed, also. In the future, these data will be used to investigate the correlation between the sound quality and measurement data.

Recently, as the quality of life of modern people improves, interest in environmental noise is gradually increasing. As the public's awareness of environmental rights increased, it was necessary to grasp the actual condition of the noise source and systematic noise management plan. The data is expected to be used as a response to noise-related complaints. As a result measured using the factory noise monitoring system, the amount of data measured every 5 minutes from 00:00 to 24:00 can obtain 288 noise levels and frequency characteristics per day, and frequency using 1/3 octave-band. The analysis reveals what frequency range affects the noise from the metal working plant near the office. In addition, it can be seen that it is possible to compare with the reference value by using the stored data divided into night time, day time, and evening time for each time zone, and it is determined that it is possible to secure smooth data about the noise source to be measured.

The purpose of this study was to establish the noise generation actual condition of large machine in plant. most of the plant's large-scale machines are designed and manufactured overseas, so it is difficult to access basic information. The regulatory standards, management plans and measurement methods for these machines are insufficient. It is necessary to obtain information about the noise storage devices installed for warranty and the noise reduction device when designing the equipment. Investigation of the occurrence of large-scale machine noise at domestic plant sites was conducted. The sound insulation design of the industrial safety and health care law benchmark and the large-scale machine compound noise design of the equipment are carried out.

The purpose of this study was to establish the noise characteristics of noise sources and the corresponding noise reduction measures during each manufacturing process closest to the workers in the metalworking factory. To this end, the noise generated in the manufacturing process of metal products was measured and analyzed, and the frequency characteristics of noise sources and the causes of noise were identified. The noise map was used to predict the noise reduction effect. Moreover, it is expected that this will ultimately contribute to the reduction of human risks caused by the noise of the civil environment around metalworking factories.

The study on the database for the noise of the large machine and high power machine. The object of this project is to prepare the countermeasure of the health care according to investigate and database the basic information of the large machine and high power machine. To accomplish the object ; The dimension and noise of the large machine, which is mounted in the factory, was investigated. And the prediction and measurement method of the noise for the machine by manufacturers were investigated. The database of the noise by the machine type and power was built. The measurement and management methods for the machine noise were considered. The database of the noise was built from the measurement data. The major sound sources and frequency range for the large machine and the high power machine were investigated. The noise effect by the large machine and the high power machine was investigated. The application fields are; The setting of the management plan of the noise which generates from the large machine and the high power machine. The effective noise reduction for the major sound source with low cost. The application as the frequency transition considering the psycho-acoustics characteristics.

A theoretical model has been studied to describe the sound radiation analysis for a railway under the action of harmony line moving forces. When a railway is analyzed, it had been modeled as curved beams with distributed springs and dash-pots that represent the radial, tangential stiffness and damping of rail, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The curved beam material and elastic foundation are assumed to be lossless Bernoulli-Euler beam theory including a tension force(T), damping coefficient(C) and stiffness of foundation(Κ2) will be employed. The expression for sound power is integrated numerically and the results examined as a function of Mach number(M), wave-number ratio(γ) and stiffness factor(Ψ).

Assessment of noise exposed population is to check the environment noise level and social influence in order to reduce the risks such as annoyance and disturbance that are generated by environmental noise. Also, this method suggests the preferential noise abatement policy and action plan by accurately finding the area that the noise causes harmful effect to human health. Recently, a noise map, which can predict noise in comprehensive area, is used for the assessment of noise exposed population, breaking from the methods using existing measures. In particular, countermeasure for noise can be considered more effectively by using assessment methods of noise exposed population for specific noise level, area, and building types which are the main input factors in noise maps. In this study, we propose noise reduction ranking decision at ship construction and repair process due to noise map.

The object of this paper is to examine the noise generating mechanism at ship construction and repair precess. To accomplish the object; A noise generating mechanism of high noise machine, which is mounted in the ship construction and repair process, was investigated. The measurement method of the noise for the machine by ship construction were investigated. The noise at the 250 points of the manufacturing process machine in the 40 processes of the 3 factories, 3 business fields was measured. The database of the noise was built from the measurement data. The major sound sources and frequency range for the manufacturing process of metal material product machine was investigated.

In contemporary society, vibration and noise in the road nearby buildings have become social problems as vehicles operation has increased. Especially, in the case of the building used to art performance, available suitability of the building is tested by the indoor noise class. Therefore, the purpose of this paper is the measurement of the structure-borne noise of Seoul Art Center nearby Umyeonsan tunnel and analyzing the effects of countermeasure to it. To measure the effects of countermeasure, not only structure-borne noise is measured, but also the vibration is measured, before and after the construction of pavement using pad and porous asphalt. Consequently, the sound pressure level in art center 1st floor is reduced after mat pavement method, structure-borne noise that was high in 25Hz wide-band before pavement decreased regardless of experimental vehicle's velocity. Using porous asphalt pavement the noise was reduced about 3 dB(A).

In contemporary society, vibration and noise in the road nearby buildings have become social problems as vehicles operation has increased. Especially, in the case of the building used to art performance, available suitability of the building is tested by the indoor noise class. Therefore, the purpose of this paper is the measurement of the structure-borne noise of Seoul Art Center nearby Umyeonsan tunnel and analyzing the effects of countermeasure to it. To measure the effects of countermeasure, not only structure-borne noise is measured, but also the vibration is measured, before and after the construction of pavement using pad and porous asphalt. Consequently, the sound pressure level in art center 1st floor is reduced after mat pavement method, structure-borne noise that was high in 25Hz wide-band before pavement decreased regardless of experimental vehicle's velocity. Using porous asphalt pavement the noise was reduced about 3 dB(A).

The objective of this paper is to compare the site-to-site variability of ISO 10844 pass by the noise test sites. In order to investigate the site-to-site variance of test surfaces, European commercial tires are tested at seven different test sites. Three Korea test sites and four Europe test sites are selected. The pass by noise test is done according to a 2001/43/EC regulation. Although the ISO surface has a very specific track composition, it does not reduce the variation of pass by noise measurements over the surface of test sites. This paper shows that the test results of pass by noise level are different depending on the test sites. The correlation obtained in this work is able to predict the pass by noise level for certain test site using the data measured from another test site. The prediction value is range with an error within 1dB(A).

In this paper, interior noise that is brought into inside of coach when it passes by straight line track, railway turnout section, curved track, and rail lubricator section with test coach was measured in accordance of track characteristic of urban railway vehicle. It was evaluated with 60km/h of constant speed in the motorized trailer, no.3 car T1 motorized trailer of urban railway vehicle. Interior noise characteristic value is higher in order of curve, rail lubricator, railway turnout, and straight track as a result of the test. The highest characteristic value is 86.7dB in the curved track. And, the lowest characteristics value is 75.5dB(A) in the straight track. For accurate result comparison, it is transformed into sound pressure distribution by time domain, sound pressure level by time domain, sound pressure level for frequency domain and completed analysis.

The tyre/road noise becomes aggravated due to the rapid increase of motor vehicles. It has a great effect on the dwelling environment. Therefore we investigate the characteristics and sources of the tyre/road noise through grasping the status of the tyre/road noise. Traffic noise results from the collective contribution of the noise produced by individual motor vehicles. The tyre/road noise varies enormously depending upon its type and mode of operation. In this study, we investigate the noise labelling of EU tire.

The noise from the exhaust system to the engine is important in terms of the problem of noise pollution, as well as improved marketability, there are many studies being made. Normally, the exhaust noise change is the exhaust manifold of the muffler or four days depending on the structure of the portion of the shape and the Lancer, called look a big difference, and the perforated pipe resonance, expression that contains a study of the structure of the muffler is a general precedent. This muffler is based on four wheel to differentiate between the borrower and the borrower can be broken down into a motorcycle. The details of the stock muffler, the muffler is tuned racing use. Therefore, this study is the last motorcycle noise and exhaust emission for environmental tests have not been established yet 125cc motor cycle noise is used as a reference for the criteria for information about the experiment. There are few types of motorcycle muffler, such as stock muffler, slip on muffler and full system muffler used racing. On this study through to the measurement motorcycle exhaust noise and analysis 1/3 octave band get a target frequency. For the design resonance muffler used Helemholtz’s resonance formular. Also when design the muffler consider mount of frame. This studied expect reduction noise without sound absorption.