• 전기학회논문지P
• /
• 제59권3호
• /
• pp.298-304
• /
• 2010

Recently, the audible sound level of power transformer has been reduced due to development of new material and enhancement of manufacturing technology. There is lack of research on the audible sound of winding and cooling fan because the research on reduction of audible sound is concentrated on the core sound. Therefore this paper describes 3 kinds(core, winding and cooling fan) of transformer sound source. Also this paper analyzes the effect of load sound and cooling fan sound on the total transformer sounds. As the results, total sound level of 79dBA class transformer rises 0.2～0.3dB due to effect of load sound and rises 2.1～3.5dB due to effect of cooling fan sound. Also, total sound level of 55dBA class transformer rises 2.3～2.9dB due to effect of load sound and rises 1.9～3.5dB due to effect of cooling fan sound.

• International Journal of Advanced Culture Technology
• /
• 제7권2호
• /
• pp.218-226
• /
• 2019

In modern society, people live in an environment with artificial or natural noise. Especially, the sound that corresponds to the artificial noise makes the noise itself and affects each other because many people live and work in the city. Sounds are generated by the activities and causes of various people, such as construction sites, aircraft, production machinery, or road traffic. These sounds are essential elements in human life and are recognized and judged by human auditory organs. Noise is a sound that you do not want to hear by subjective evaluation, and it is a loud sound that gives hearing damage or a sound that causes physical and mental harm. In this study, we introduce the method of stimulating the human hearing by finger vibration and explain the advantages of the proposed method in various kinds of a noise environment. And how to improve the sound quality to improve efficiency. In this paper, we propose a method to prevent the loss of hearing loss and the transmission of sound information based on proper signal to noise ratio when using portable IT equipment in various noise environments.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 추계학술대회논문집
• /
• pp.654-660
• /
• 2006

There are various sounds in the car as much as cats have many mechanical parts. These sounds make various sound qualities. The international competition in car markets has continuously required the research about the sound quality of a car. The domestic carmakers have also invested a lot of money for the research and development of sound quality. Car axle plays an important role in a vehicle and its NVH development is also important. By this time, NVH development of car axle is mainly based on the reduction of sound pressure level(dBA), which cannot gives, the satisfaction to the customers in view of the sound quality of a vehicle. Therefore, in this project, a sound quality index evaluating the sound quality of axle noise based on human sensibility is developed and applied to the development of the sound quality of axle noise

• International journal of advanced smart convergence
• /
• 제5권4호
• /
• pp.15-20
• /
• 2016

When a virtual sound source for 3D auditory system is reproduced by a linear loudspeaker array, listeners can perceive not only the direction of the source, but also its distance. Control over perceived distance has often been implemented via the adjustment of various acoustic parameters, such as loudness, spectrum change, and the direct-to-reverberant energy ratio; however, there is a neglected yet powerful cue to the distance of a nearby virtual sound source that can be manipulated for sources that are positioned away from the listener's median plane. This paper address the problem of generating binaural signals for moving sources in closed or in open environments. The proposed perceptual enhancement algorithm composed of three main parts is developed: propagation, reverberation and the effect of the head, torso and pinna. For propagation the effect of attenuation due to distance and molecular air-absorption is considered. Related to the interaction of sounds with the environment, especially in closed environments is reverberation. The effects of the head, torso and pinna on signals that arrive at the listener are also objectives of the consideration. The set of HRTF that have been used to simulate the virtual sound source environment for 3D auditory system. Special attention has been given to the modelling and interpolation of HRTFs for the generation of new transfer functions and definition of trajectories, definition of closed environment, etc. also be considered for their inclusion in the program to achieve realistic binaural renderings. The evaluation is implemented in MATLAB.

• 한국항해항만학회지
• /
• 제27권2호
• /
• pp.145-153
• /
• 2003

가상현실 (VR) 시뮬레이터의 임장감 증대방법을 제안했다. 이 방법은 입체영상과 3차원음향 사이의 상호 상승효과에 의하여 인간이 느끼는 현실감을 증대시키기 위한 것이다. 상호 상승효과를 실험하기 위하여 PC 모니터와 LCD 셔터그래스로 구성된 VR 시뮬레이터를 이용하여 5명의 대학생을 대상으로 주관평가를 실시하였다. 실험결과, 입체영상에 3차윈음향을 부가한 경우, 자연감을 나타내는 척도 $I_{nat}$ 가 3.1에서 3.6으로 0.5 상승하고, 음상정위 평가척도 $A_{SL}$ 는 70~75%에서 80~85% 로 10% 상승하는 결과를 나타냈다. 따라서, 이 연구에서 제안한 방법이 VR 시뮬레이터의 현실감을 증대시킬 수 있었다.

• 가정과삶의질연구
• /
• 제17권3호
• /
• pp.93-102
• /
• 1999

This paper is to clarify the concepts of "sound home" and "healthy family" Even though "sound home" and "healthy family have different meanings and definitions. many researchers are using them in a mixed ways. Therefore through this paper I tried to make distinction of the meanings of the above concepts as below: 1. Sound Home : Basic and fundamental social units and environment which have strong and healthy family members and performs well not only family function but also have attitudes and willingness to perform family function and maintain their family value and ethics. 2. Healthy Family : Social units which have strong and healthy family members and develop individual personal development -their physical emotional social moral development and self-esteem self-achievemet -and have good interaction enhancement skills- communication decision making stress managing strategies- and also maintain family systems. Whereas "sound home" is more broad concept related to Home Econom cs "healthy family" is more related family relations and interaction.quot; is more related family relations and interaction.

• 한국수자원학회논문집
• /
• 제46권3호
• /
• pp.267-276
• /
• 2013

본 연구는 어류서식 적합도 향상을 위한 하천구조 개선 방안을 위한 연구이다. 이를 위해 대상하천의 유역 및 수중환경조사와 어류의 군집특성 결과를 이용하여 건전한 수중생태계를 대표할 수 있는 복원 목표어종으로 참갈겨니를 선택하였다. PHABSIM을 이용한 검증결과 유속과 수심에 대한 적합지수 향상을 위한 저수로 폭의 변화는 대상어종의 서식적합도 향상을 가져왔음을 알 수 있었다. 그러나 서식적합지수 향상을 위한 저수로 폭의 변화는 일관성 있는 서식적합도의 향상을 나타내지 못함을 확인하였다. Genetic Algorithm을 이용하여 대상하천의 서식적합도 개선을 위한 주어진 유지유량에 따른 하천 구간별 유속, 수심을 고려한 저수로 폭의 최적 방안을 제시하였다. 저수로 단면 구조개선의 방안 제시는 수계환경개선을 위한 각종 사업에 기여할 것으로 판단된다.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1999년도 학술발표대회 논문집 제18권 2호
• /
• pp.237-242
• /
• 1999

In this study, a design method using plane actuator is developed to make new speaker system, whose shape is much thinner than that of conventional loudspeaker. Piezofilm(PVDF) is used as plane actuator of flat speaker. To avoid the distortion of sound radiated from flat speaker, the frequency response of radiated sound to be flat is taken as the design objective. The electrode pattern and orientation angle of piezofilm actuator is optimized to satisfy the design objective. The formulation is based on the coupled finite element and boundary element method. Genetic algorithm is used in the optimization process, which is useful in the optimization of discrete design variables. Frequency response with optimized piezofilm actuator is made flat enough to satisfy the design objective. For the enhancement of sound power, double-layered piezofilm actuators are also considered. The sound power with double-layered actuator becomes larger than that with single-layered actuator as expected.

• 산업기술연구
• /
• 제18권
• /
• pp.439-442
• /
• 1998

In this paper, we firstly suggested C&D (Common mode and Differential mode) model for the representation of a stereophonic signal. Then a measure of stereophonic channel separability is defined as the ratio of differential mode energy to total energy in frequency domain. After that, a new channel separability enhancement scheme is proposed by the control of common mode rejection. Finally, some experimental results are presented in order to verify our scheme.

• 한국음향학회지
• /
• 제28권6호
• /
• pp.557-565
• /
• 2009

인간의 청각기관은 소리의 방향과 거리인지에 있어서 여러 가지의 정보들을 복합적으로 이용한다. 이러한 양 귀에 들어오는 소리세기의 차이, 위상의 차이, 그리고 주파수 스펙트럼의 차이 등의 정보들을 종합적으로 포함하고 있는 것이 머리전달함수 (HRIF: Head Related Transfer Function)이다. 2채널 음향재생 시스템에서 이 머리전달함수를 이용하여 다채널 입체음향을 재생하는 방법이 많이 쓰이고 있다. 그러나 머리전달함수의 비개인화적인 특성 때문에 양쪽 귀까지의 거리가 같아지는 혼돈원추 상에서는 앞/뒤 방향 지각에 대한 혼돈을 주게 됨으로써 입체감을 저하시키게 된다. 본 논문에서는 입체음향을 생성하기 위해 머리전달함수를 사용하는 과정예서 발생하는 혼돈원추 문제점을 해결하기 위한 알고리즘을 제안한다. 각 머리전달함수의 주파수 차 및 인간의 청각 특성을 이용하여 각 방향에 해당하는 머리전달함수의 주파수 스펙트럼 특성을 조절하였다. 본 알고리즘의 성능을 평가하기 위하여 음상정위 테스트 및 청감 테스트를 실시하였으며 실험 결과 헤드폰을 기반으로 한 2채널 입체음향 시스템에서 향상된 입체음향을 재생하였다. 더불어 구현된 입체음향의 음질의 열화도 적음을 확인할 수 있었다.