• 제목/요약/키워드: Octave

검색결과 216건 처리시간 0.025초

기존선을 주행하는 무궁화호 열차의 소음원 모델링과 음향강도 평가에 관한 연구 (Study on the Noise Source Modeling and the Source Strength Estimation of Mugungwha Trains Running on the Conventional Railway)

  • 장승호;장은혜
    • 한국소음진동공학회논문집
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    • 제23권11호
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    • pp.1020-1026
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    • 2013
  • An accurate railway environmental noise prediction model is required to make the proper solution of the railway noise problems. In this paper, an engineering model for predicting the noise of conventional passenger cars is presented considering the acoustic source strength in octave-band frequencies and the propagation over grounds with varying surface properties. Since the formation of a train can be variable, the source strength of each locomotive and passenger car was estimated by measuring the pass-by noise and analysing the wheel-rail rolling noise. Some validation cases show on the average small differences between the predictions of the present model and the measurement results.

기존선 여객열차의 환경소음 예측모델 연구 (Study on the prediction model of environmental noise from the conventional railway passenger cars)

  • 장승호;장은혜;손정곤;박병주
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2013년도 추계학술대회 논문집
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    • pp.564-569
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    • 2013
  • An accurate railway environmental noise prediction model is required to make the proper solution of the railway noise problems. In this paper, an engineering model for predicting the noise of conventional passenger cars is presented considering the acoustic source strength in octave-band frequencies and the propagation over grounds with varying surface properties. Since the formation of a train can be variable, the source strength of each locomotive and passenger car was estimated by measuring the pass-by noise and analysing the wheel-rail rolling noise. Some validation cases show on the average small differences between the predictions of the present model and the measurement results.

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실 음향에서의 잔향 시간 측정 개선에 관한 연구 (A New Method for the Reverberation Time Measurement on Acoustic Rooms)

  • 이상권;이민성;김봉기
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2001년도 추계학술대회논문집 II
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    • pp.1104-1108
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    • 2001
  • It is a difficult and important task to measure the reverberation time of an acoustic room with a short reverberation time. This paper presents a new technique to measure the reverberation time of an acoustic room with low value of BT60. The digital signal processing technique used to do this is the wavelet filter which is very flexible to design the 1/n octave band filter and has no delay problem compared with the conventional IIR digital filter. This method is successfully applied to the measurement of the reverberation time at low frequency band of famous concert halls in Korea.

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공동주택 입주 전.후 세대에서의 잔향시간 측정 및 비교 (Field Measurement of the Reverberation Time in Occupied and Unoccupied Apartment Houses)

  • 이병기;김병준
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 추계학술대회논문집
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    • pp.654-657
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    • 2005
  • The aim of this study is to investigate and to analyze the reverberation times of apartment houses Measurements were conducted in a total of 44 rooms(36 rooms were in occupied houses and 8 rooms were in unoccupied houses) according to KS F 2864. The results showed that the averaged reverberation time of the occupied and the unoccupied houses were about 0.3$\sim$0.5sec and 1.2$\sim$l.5 sec, respectively, at 500Hz octave band frequency. And the averaged absorbtion coefficient of the occupied and the unoccupied houses were about 0.13$\sim$0.35 and 0.11$\sim$0.20, respectively. In addition, We verified that the reverberation time generally depended on the frequency; the lower the frequency, the higher the reverberation time.

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천장형 시스템 에어컨의 음향 특성 (Acoustical Characteristics of System Air Conditioners Installed in the Ceiling)

  • 김수연;유진;전진용
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 추계학술대회논문집
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    • pp.662-665
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    • 2005
  • In this study acoustical characteristics of system air conditioner in different ceiling systems was investigated in anechoic and real conditions. Same Types of air conditioners were installed in two different rooms. The results showed that motor's tonal component was emphasized at near fart of air blast blower in the exposed type while fan's harmonic component is emphasized rather in the enclosed type. This confirms tile result of acoustical intensity mapping which showed that Intensity level of 125Hz octave band increased in the exposed type while there was no noticeable difference at the frequency band in the enclosed type.

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철도궤도의 동적특성 예측 및 실험적 검증 연구 (Prediction of The Rail way Track's Vibration Behavior and Corresponding Experimental Verification)

  • 박희준;김관주;김재철;이찬우
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.883-888
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    • 2004
  • One of commercial rapid transits produces peculiar booming sound when passing through the slab-track tunnel. In order to analyze that tympanic membrane-pressing noise systematically, typical source-transfer path-response analysis was carried out. Considering the octave band of booming noise, work scope was confined to structure-borne noise analysis, especially the dynamic behaviour of railway tracks. Experimental modal analysis of railway tracks, composed of rail, rubber pad, sleeper, ballast, and ground were performed. The results shows that transversal bending modes of the rail are suspicious for the cause of the low band booming noise. Finite element analysis are made use of to match preceding experimental results, and plausible dynamic properties of track components are produced.

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덕트형 소음기 설계 프로그램 개발 (Development of Design Program for Duct Silencer)

  • 김인수
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 추계학술대회논문집
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    • pp.379-383
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    • 2000
  • This paper describes the design program of duct silencer. Duct silencer is used ventilating system. Variables in the program for predicting transmission loss are width of splitter, airway width, perforate plate, absorption material and frequency. Generally used expression for predicting transmission loss has something that don't think about frequency characteristic. Therefore we propose the new expression that considered frequency characteristic. In the 1/1 octave band center frequency, the expected weighting number(K) is fitted with absorption ratio and airway width. The fitted 2nd degree polynomial expression is based on the test data performed in YOUIL Industrial Corperation. This program's accuracy is about 90 percent.

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딥 러닝 기반의 SIFT 이미지 특징 검출 (SIFT Image Feature Detect based on Deep learning)

  • 이재은;문원준;서영호;김동욱
    • 한국방송∙미디어공학회:학술대회논문집
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    • 한국방송∙미디어공학회 2018년도 추계학술대회
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    • pp.122-123
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    • 2018
  • 본 논문에서는 옥타브(sacle vector, octave)를 0, 시그마(sigma)는 1.6, 간격(intervals)은 3으로 설정하여 검출한 RobHess SIFT 특징들로 데이터 셋을 만들어 딥 러닝 모델인 VGG-16을 기반으로 SIFT 이미지 특징을 검출하는 방법을 제안한다. DIV2K 데이터 셋을 $33{\times}33$ 크기로 잘라서 데이터 셋을 구성하였고, 흑백 영상으로 판별하는 SIFT와는 달리 RGB 영상을 사용 하였다. 영상을 좌 우 반전, 밝기, 회전, 크기를 조절하여 원본 영상을 변형시켜 네트워크 학습 및 평가를 진행하였다. 네트워크는 영상의 가운데에 위치한 픽셀이 특징점인지 아닌지를 판별한다. 검증 데이터의 결과 98.207%의 정확도를 얻었다.

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사상체질음성분석기(四象體質音聲分析機)(PSSC-2004)를 이용한 한국인 소아의 체질별(體質別) 음향특성(音響特性) (Sound Characteristics of Sasang Constitutional Type Using PSSC-2004 in the Korean Children)

  • 김혁;양상묵;심규헌;김달래;유준상
    • 사상체질의학회지
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    • 제18권2호
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    • pp.55-67
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    • 2006
  • 1. Objective & Method The purpose of this study was to objectify the diagnosis of Sasang constitution. 163 children's voices were analyzed with 74 factors using PSSC-2004. 2. Results (1) In male children group, Taeumin's APQ4 was significantly low compared with the others. (2) In male children group, Taeumin's octave 5 & octave 6 were significantly low compared with the others. It was significant distinction between Taeumin and Soeumin at the result of post hoc. (3) In male children group, Taeumin's Time Domain Total Sum / Time Domain Count & Frequency Domain Total Sum / count(0) were significantly low compared with the others. It was significant distinction between Taeumin and Soeumin at the result of post hoc. (4) In male children group, Taeumin's 0k-2k total sum & 2k-4k total sum were significantly low compared with the others. It was significant for distinction between Taeumin and Soeumin at the result of post hoc. (5) In male children group, Taeumin's 2k-4k deviation was significantly low compared with the others. It was significant distinction between Taeumin and Soeumin at the result of post hoc. (6) In male children group, Taeumin's D# Total Energy & F# Total Energy were significantly low compared with the others. It was significant distinction between Taeumin and Soeumin at the result of post hoc. (7) In male children group, Taeumin's D# deviation & F# deviation were significantly low compared with the others. It was significant distinction between Taeumin and Soeumin at the result of post hoc. (8) In female children group, Soyangin's center frequency (7) was significantly high compared with the others. It was significant distinction between Taeumin and Soyangin at the result of post hoc. 3. Coclusion With these results, we got some information for standardization of the clinical diagnosis guideline of Sasang constitutional type classification using PSSC-2004 in the Korean children

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Octave를 이용한 전기 요금 최소화를 위한 ESS 운전 전략 최적화 방법에 대한 분석 (An Analysis of Optimal Operation Strategy of ESS to Minimize Electricity Charge Using Octave)

  • 공은경;손진만
    • 한국산학기술학회논문지
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    • 제19권4호
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    • pp.85-92
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    • 2018
  • 수요관리를 통해 전기요금을 절감할 수 있다. 부하의 수요 관리 방법 중 하나로 ESS를 설치해 수요가 높은 시간대의 부하를 수요가 낮은 시간대로 옮기는 peak shifting을 사용함으로써 최대 부하를 낮추고 전력량 요금을 절감할 수 있다. 전기요금은 계약 용량 당 기본요금과 전력량 요금으로 이루어져있다. 전력량 요금을 최소화하기 위한 최적화 수행시 목적함수는 선형식으로 표현할 수 있으며, 기본 요금 최소화를 위한 목적함수는 이차식으로 표현할 수 있다. 선형식으로 표현된 목적함수에서는 ESS PCS(Power Conversion System)의 충, 방전 효율이 다른 경우를 다룰 수 없기 때문에 본 논문에서 충, 방전 효율이 다른 경우의 영향을 반영하고 혼합정수계획법(MILP, Mixed Integer Linear Programming)을 이용할 수 있는 정식을 제시하였다. 혼합정수계획법을 사용한 정식에서는 사전에 정해진 최대 부하 절감율에 대해 전기요금 최소화를 수행하게 되지만 최대 부하 절감과 전기요금 절감을 동시에 고려하기 위해서는 이차 계획법을 사용하는 것이 유용하다. 본 논문에서는 각 최적화 방법에 대한 장, 단점을 도시철도 변전소에 대한 시뮬레이션 결과를 정량적으로 비교분석하여 ESS 설비계획수립에 적합한 최적화 방법을 선택할 수 있는 근거를 제시하였다.