• 한국소음진동공학회논문집
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• 제22권9호
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• pp.853-860
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• 2012

This paper identifies a cause of pick up noise in a laser printer and a relationship between pick up noise and major components related to pick up noise. A pick up sound is affected by many components such as spring force, spring constant, and friction coefficient. Objective evaluation for the pick up sound is difficult because of back ground sound such as operating sound. Especially, a sound between a friction pad and a paper in the process of printing has become an essential issue in an aspect of quality evaluation. However the existing criteria for determining the above sound have solely relied on human's subjective judgments; which highlights the requirement to objectify these criteria. In this paper, the standard of existing pick up noise is established by finding the tonality, which is a psychoacoustic parameter, of noticeable limit sound level. Based on the findings of the method, the study has found factors which cause pick up noise and suggests the substitution of following components of printers such as spring constants, spring force, and the quality of friction pads. As a result, it is confirmed that the proposed pick up noise index has usefulness to classify whether existence of pick up noise with an objective evaluation and not to occur the noise based on design optimized combination of laser printer components.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.330-332
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• 2003

In this paper, It is introduced new sound quality method, FI(Fluctuation Index) and the example applied Outdoors side Air-conditioner noise evaluation. Because FI is applied with very simple algebraic calculation algorithm, it can be applied some other application without spending high time and cost.

• Journal of Oral Medicine and Pain
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• 제35권2호
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• pp.135-147
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• 2010

본 연구에서는 최근 Sato 등이 고안한 mixing ability index(MAI)를 이용하여 측두하악장애 환자 중 통증이 있는 군과 무통성 관절잡음이 있는 군을 대상으로 객관적인 저작 효율을 정상인으로 구성된 대조군과 비교하고, 주관적인 평가 방법인 설문조사법 중에서 음식섭취가능지수(Food Intake Ability Index, FIA)와 저작 능력에 대한 주관적 인식도 평가(Visual Analogue Scale, VAS)를 이용하여 저작 효율을 평가하고, 구강건강과 관련된 삶의 질을 평가하기 위해 Oral Health Impact Profile(OHIP)-49K 설문조사를 시행하였다. 각 평가 방법 간의 상관성을 알아보고, 또한 통증군에 있어서는 치료 후 통증이 감소함에 따라 저작 효율의 변화 양상을 조사하여 다음과 같은 결과를 얻었다. 1. MAI, FIA, VAS는 통증군이 정상군에 비해 통계학적으로 유의하게 감소하였으며, 관절잡음군보다도 감소하여 통증군이 정상군과 관절잡음군에 비해 저작 효율이 떨어지는 것으로 나타났다(P<0.05). 관절잡음군에서는 MAI, FIA, VAS에서 정상군과 유의한 차이를 보이지 않았다. 2. 구강건강관련 삶의 질에 대한 설문지인 OHIP-49K의 경우 정상군에 비해 통증군과 관절잡음군 모두 통계학적으로 유의하게 증가하여 구강건강과 관련한 삶의 질이 떨어지는 것으로 나타났다. 3. 전체 대상자(71명)에서 객관적 저작 능력 평가 방법인 MAI와 주관적 저작 능력 평가 방법인 FIA와 VAS간에는 서로 유의성 있는 상관관계를 보였다(P<0.01). OHIP-49K에서도 MAI를 제외하고 모두 통계학적으로 상관관계가 있는 것으로 나타났다. 4. 관절잡음군에서는 FIA와 VAS에서만 통계학적으로 상관관계가 있는 것으로 나타났으며(P<0.01), 이외의 모든 항목은 상관관계가 없는 것으로 나타났다. 5. 각 평가 방법 간의 상관성에서 FIA와 VAS는 전체 대상자, 통증군, 관절잡음군 모두에서 상관관계가 있는 것으로 나타났다. 6. 통증군에서 치료 전에 비해 치료 후 통증 감소와 함께 VAS에서는 통계학적으로 유의성 있게 증가 하였다(P<0.05). 반면에 MAI에 있어서는 저작 효율이 증가하는 경향을 보였으나 통계학적 유의성은 없었다. 또한 FIA, OHIP-49K에서도 치료 전과 후 통증 감소에 따른 변화는 없는 것으로 나타났다. 이번 연구를 통하여 측두하악장애 환자에서 저작 효율을 감소시키는 주요인은 통증이며, 관절잡음은 저작 효율을 감소시키는 요인은 아니지만 삶의 질을 저하시키는 한 요인으로 작용한다는 것을 알 수 있었다. 따라서 측두하악장애 환자에서 저작 효율을 개선시키기 위해서는 우선적으로 통증을 치료하는 것이 가장 중요하며, 삶의 질을 향상시키기 위해서는 통증뿐만 아니라 관절잡음에 대한 관리도 필요할 것으로 사료된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.661-665
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• 2006

This study investigates objective and subjective evaluations of refrigerator noise. To describe the fluctuations like a click, a rapid increase of sound level, a change of pitch, a transition into the stationary and ending phase, the psychoacoustical and autocorrelation function(ACF) parameters have been employed. First, subjective evaluation of the noisiness of 24 kinds of refrigerators was conducted. Then, the relationship between objective measures of the refrigerator noise on perceived noisiness was examined with multiple regression analyses. Sound Quality Indices using the psychoacoustical and ACF parameters were also developed. The important psychoacoustical parameters for evaluating noisiness are loudness and roughness of stationary phase. The relationship between the noisiness and the ACF parameters shows that sound energy ${\Phi}(0)$ and its fluctuations are important. Also, refrigerator sounds that had a fluctuation of pitch were rated as more annoying. The fluctuation of pitch is expressed by ${\tau}_1\;and\;{\Phi}_1$ defined by the delay time and the amplitude of the first peak of the ACF.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.634-637
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• 2007

A weighted sound pressure level has been used to evaluate sounds test or sound quality test for a refrigerator up to present but the customer had different satisfactions of refrigerator sounds with different listening position. It means that there was a sound directivity caused by a position of fan or compressor. In this paper, we proposed a sound power spectrum guideline that represents total sound of refrigerator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1062-1066
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• 2004

In this study, refrigerant noise at connection of capillary tube and evaporator is investigated. Mechanism of refrigerant noise generation is examined in side-by-side type home refrigerator with two evaporators. It is found that the refrigerant noise is generated during refrigeration room fan-off (R-fan of) for that type refrigerator. The reason is that mass flow rate gets down during R-fan of and flow pattern is changed at outlet of capillary tube. We suggest designs for reduction of refrigerant noise with horizontal double expansion device, muffler, and accumulator. To evaluate those improved designs, sound quality index is used.

• 소음진동
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• 제6권4호
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• pp.499-502
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• 1996

Interior noise, engine speed and vehicle speed are measured under transient road-load condition and interior noise signal is transformed by using the transient signal analysis methods, such as the spectrogram and wavelet transform. Using the analyzed results, subjective noise metrics such as the loudness, sharpness and articulation index at each vehicle speed can be estimated and characteristics of interior noise for various running modes can be discussed in the viewpoint of noise quality.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권4호
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• pp.374-385
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• 2012

The indoor noise of a ship is usually determined using the A-weighted sound pressure level. However, in order to better understand this phenomenon, evaluation parameters that more accurately reflect the human sense of hearing are required. To find the level of the satisfaction index of the noise inside a naval vessel such as "Loudness" and "Annoyance", psycho-acoustic evaluation of various sound recordings from the naval vessel was performed in a laboratory. The objective of this paper is to develop a single index of "Loudness" and "Annoyance" for noise inside a naval vessel according to a psycho-acoustic evaluation by using psychological responses such as Noise Rating (NR), Noise Criterion (NC), Room Criterion (RC), Preferred Speech Interference Level (PSIL) and loudness level. Additionally, in order to determine a single index of satisfaction for noise such as "Loudness" and "Annoyance", with respect to a human's sense of hearing, a back-propagation neural network is applied.

• 한국물환경학회지
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• 제22권5호
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• pp.748-756
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• 2006

Accurate and timely information on status and trends in the environment is necessary to shape sound water quality management policy and to implement water quality improvement programs efficiently. One of the most effective ways to communicate information on water quality trends to policy-makers, scientists, and the general public is with comprehensive water quality indices. The derivation and structure of a water quality index (WQI) for the classification of surface water quality is discussed. The WQI generally developed through the selection, transformation and weighting of determinants with rating curves based on legal standards and quality directives or guidelines. The representative pollutants should be included in the index, and the relationship between the quantity of these pollutants in the water and the resulting quality of the water should be based on scientific results. The WQI be simply and meaningfully formulated that nonscientifically trained users can easily become familiar with the framework of the system and use the output data to evaluate their own pollution problems.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1871-1876
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• 2010

사람이 소리를 듣는 것은 다분히 감정적이고 주관적으로 이루어진다. 따라서 소음 측정의 척도로 주로 사용되는 dB(A)와 같은 청감을 고려한 수치로 표현하기 어렵기 때문에 때와 장소, 차량에 따라 주관적이고 사람의 감정에 맞는 주관적 척도가 요구된다. 즉, 평가하고자 하는 음질인자 항목들은 독립적 관계가 아닌 서로 상관관계의 특성을 고려하여 음질 평가를 수행해야 한다. 그러므로 인간의 청감에 가깝고 정확한 음질 평가를 위해서는 음질인자 별 다변량 분석이 필요하다. 본 연구에서는 차량 주행 소음을 대상으로 특성인자간 상관관계를 고려해 시스템을 분석할 수 있는 마할라노비스 거리(Mahalanobis distance,MD)를 통해 음질 인덱스를 구축하고자 한다.