Characteristics of underwater ambient noise at a proposed tidal energy site in puget sound
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Ambient underwater acoustics data are presented for one year at a potential tidal energy site in Admiralty Inlet, WA (USA) with maximum currents exceeding 3 m/s. The site, at a depth of approximately 60 meters, is located near shipping lanes, a local ferry route, and a transit area for many cetacean species. A key finding is that the statistical distribution of total sound pressure levels are dependent on tidal currents at the site. Pseudosound, cobbles shifting on the sea bed, and vibrations induced by forces on the equipment are possible explanations. Non-propagating turbulent pressure fluctuations, termed pseudosound, can mask ambient noise, especially in highly energetic environments suitable for tidal energy development. A statistical method identifies periods during which changes in the mean and standard deviation of the one-third octave band sound pressure levels are statistically significant and thus suggestive of pseudosound contamination. For each deployment, recordings with depth averaged tidal currents greater than 1 m/s are found to be contaminated, and only recordings with currents below this threshold are used in the subsequent ambient noise analysis. Mean total sound pressure levels (0.156 - 30 kHz) over all recordings are 117 dB re 1μPa. Total sound pressure levels exceed 100 dB re 1μPa 99% of the time and exceed 135 dB re 1μPa 4% of the time. Commercial shipping and ferry traffic are found to be the most significant contributors to ambient noise levels at the site, with secondary contributions from rain, wind, and marine mammal vocalizations. Post-processed data from an AIS (Automatic Identification System) receiver is used to determine the location of ships during each recording. Referencing 368 individual recordings with the distance between the ferry and the site obtained from AIS data, the source level of the ferry is estimated to be 179 ± 4 dB re 1μPa at 1m with a logarithmic spreading loss coefficient of 18.Keywords:
Ambient noise level
Sound energy
Ambient pressure
A coupled room system consists of adjacent rooms and apertures where the sound energy is exchanged between the two rooms. Acoustically, a coupled room system shows a non-exponential decay profile. Most of the related researches have been to analyze the acoustic properties of two-room coupled system so far whereas three-room coupled system were seldom studied. In this regard, this paper aims to analyse the distribution of sound pressure level, sound decay curve of three-room coupled system and sound energy flow between them by using the acoustic diffusion model and to further verify them through experiments. Firstly, the sound pressure level distribution and mean sound pressure level in the steady-state condition are analyzed at various frequencies and source locations. Good agreements are observed in both experiments and analysis results. Secondly, two double slope effect quantifiers of sound attenuation, LDT/EDT and LDT/T10 are compared at various frequencies and for different source locations. The result indicates that LDT/T10, less affected by the early reflection patterns than LDT/EDT, is more suitable to the analysis and experiments of a multi-slope sound decay curve. Lastly, the sound energy flow in each room is analyzed based on the acoustic diffusion model. After the early decay stage, the sound energy is observed to flow from the room with a long reverberation time to the room with a short one.
Sound energy
Acoustic attenuation
Reverberation room
Reflection
Room acoustics
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Enclosure
Sound energy
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Acoustic attenuation
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В статье автор рассматривает отношение жителей большого города к малоизученным в России нестандартным рекламным медиа в контексте городского социокультурного пространства. Ненавязчивой, встроенной в окружающую среду и повседневные практики человека рекламной коммуникацией становится Ambient media: реклама на дорогах, лестницах, скамейках, парковых насаждениях, квитанциях. Такая форма рекламы предлагает инновационные схемы взаимодействия как с потребителем, так и с окружающей средой. Ambient media благодаря своей специфике способна изменять представления человека о социокультурном пространстве. Также существенным оказывается влияние Ambient-рекламы на восприятие города его жителями. Автором проведены социологические исследования с использованием качественной стратегии глубинных интервью с представители рекламного сообщества г. Екатеринбурга (N=22) и фокус-групп с активными горожанами, наиболее часто взаимодействующими с коммуникативным пространством города: студентами, родителями, деятелями науки, искусства и культуры и представителями бизнес-сообщества. Целью исследования стало изучение влияния новых форм рекламы на восприятие города и определения идентичности к своему городу. Роль Ambient мedia в жизни города заключается не только в маркетинговой передаче информации о товаре, но и в заботе о горожанах, улучшении городской инфраструктуры, новых возможностях для общения и знакомства горожан, спонтанного объединения их по интересам. Исследование зафиксировало, что Ambient мedia преобразует городскую среду в более полезную, комфортную и привлекательную для горожан. Тем самым, Ambient мedia способствует формированию идентичности индивида с городским пространством и восприятию города как «своего» и «родного»
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Ambient noise level
Ambient Intelligence
Ambient space
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Статтю присвячено дослідженню сутності ambient-маркетингу та можливостей його ефективного впровадження в комплекс маркетингових комунікацій підприємства. Зазначено, що ambient-маркетинг доцільно розглядати як нетипову рекламу з основними акцентами на нестандартних носіях та їх розміщення в довколишньому середовищі. З’ясовано головний принцип ambient-маркетингу, який полягає у тому, що рекламна інформація інтегрується у навколишнє середовище споживача, тобто розташовується у несподіваних місцях, викликає здивування, стимулює сильний емоційний відгук у потенційного споживача, породжує бажання спробувати товар/послугу. Показано, що технології ambient-маркетингу ефективні там, де підприємство може “спіймати і здивувати”. Досліджено, завдяки чому реклама в навколишньому середовищі викликає повагу та зацікавленість споживачів, хоча і не орієнтована на масову аудиторію. Встановлено відмітні особливості ambient-реклами. Визначено сильні та слабкі сторони ambient-маркетингу з погляду ефективного його впровадження в маркетингові комунікації для посилення конкурентних переваг підприємства. Підкреслено, що технології ambient-маркетингу дозволяють кожен довколишній простір використовувати як потенційний носій для презентації товарів/послуг, думок, ідей і спілкування підприємства з потенційними клієнтами. Наведено перелік носіїв ambient-реклами та приклади її оригінального розміщення у нетрадиційних місцях. Наголошено, що ambient-маркетинг у сучасних умовах є одним із кращих засобів прориву на ринки товарів і послуг через особливості маркетингової комунікації з потенційними споживачами, посилення іміджу підприємства та лояльності покупців.
Ambient pressure
Ambient noise level
Ambient vibration
Ambient Intelligence
Ambient space
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A coupled room system consists of adjacent rooms and apertures where the sound energy is exchanged between the two rooms. Acoustically, a coupled room system shows a non-exponential decay profile. Most of the related researches have been to analyze the acoustic properties of two-room coupled system so far whereas three-room coupled system were seldom studied. In this regard, this paper aims to analyse the distribution of sound pressure level, sound decay curve of three-room coupled system and sound energy flow between them by using the acoustic diffusion model and to further verify them through experiments. Firstly, the sound pressure level distribution and mean sound pressure level in the steady-state condition are analyzed at various frequencies and source locations. Good agreements are observed in both experiments and analysis results. Secondly, two double slope effect quantifiers of sound attenuation, LDT/EDT and LDT/T10 are compared at various frequencies and for different source locations. The result indicates that LDT/T10, less affected by the early reflection patterns than LDT/EDT, is more suitable to the analysis and experiments of a multi-slope sound decay curve. Lastly, the sound energy flow in each room is analyzed based on the acoustic diffusion model. After the early decay stage, the sound energy is observed to flow from the room with a long reverberation time to the room with a short one.
Sound energy
Acoustic attenuation
Reverberation room
Reflection
Energy distribution
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Sound perception by marine animals may be affected by the particle velocity on the pressure of ambient noise. Levels of ambient noise measured with a velocity hydrophone in very shallow water were found to be considerably above the associated pressure levels, particularly at low frequencies. This difference is probably due to nearfield components of ambient particle motion and may be important in acoustic signal detection by mechanoreceptor organs.
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Hydrophone
Particle velocity
Particle (ecology)
Ambient pressure
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The spatial correlation of the sound pressure and the particle velocity in surface-generated noise was investigated.Method of calculating the correlation between the sound pressure and the particle velocity in ambient noise was developed based on ray treatment.The correlation of the sound pressure and the particle velocity in ambient noise model with given surface and bottom power reflection coefficients and volume absorption could easily be got by numerical integration.Results of given condition were shown.
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The paper presents a method of sound energy characteristics calculation in premises with bulky equipment at mirror-diffuse character of sound reflection from enclosures. At such character of reflection a part of sound energy falling on an enclosure is reflected specularly, and the other part is dissipated under the Lamberts law. Sound pressure levels in reference points of a premise are determined by the sum of direct sound energy emitted by sound sources and energy of mirror and diffuse components of reflected sound field. The numerical method is proposed for calculation of sound energy density and the subsequent determination of sound pressure levels. The method is developed on the basis of the combined design model in which the mirror component of the reflected sound energy is determined by ray-tracing method and the diffuse energy component is calculated by numerical statistical energy method. The equations for determination of density of the direct, mirror-reflected and diffused sound energy are provided and technique of realization of the design model is given. The proposed method takes into account space-planning features of premises, presence of bulky equipment, sound absorption characteristics of enclosures and the nature of sound reflection from surfaces, and provide an opportunity to solve problems of estimating noise in industrial premises. The comparison of the calculated and experimental data obtained for rooms of different sizes and shapes in the absence and presence of bulky equipment confirmed the adequacy of the proposed calculation model for the description of noise field formation in such conditions. It is shown that divergences of calculation and experimental data do not exceed ±2÷3 dB in octave bands with central frequencies equal or more than 250 Hz.
Sound energy
Reflection
Statistical energy analysis
Realization (probability)
Soundproofing
Enclosure
Sound speed gradient
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The sound wave generated by sound sources is reflected by interior walls and it leads to raise the sound energy density in the structure like subway tunnel. Then this sound wave with high sound energy density propagates both toward entrance and exit of tunnel and it radiates out of that tunnel. Therefore this study was performed to investigate both the sound pressure reflection coefficient and the acoustic directivity about radiated noise from tunnel exit using experiment and acoustic analysis according to the exit shape of tunnel. Through investigating sound pressure reflection coefficient and acoustic directivity, we tried to figure out the characteristics of propagated sound from tunnel exit. From the both experimental and analytical results, it was found that higher sound reflection coefficient was measured under the condition that inclined tunnel exit degree was getting bigger.
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Directivity
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Reflection coefficient
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Ambient underwater acoustics data are presented for one year at a potential tidal energy site in Admiralty Inlet, WA (USA) with maximum currents exceeding 3 m/s. The site, at a depth of approximately 60 meters, is located near shipping lanes, a local ferry route, and a transit area for many cetacean species. A key finding is that the statistical distribution of total sound pressure levels are dependent on tidal currents at the site. Pseudosound, cobbles shifting on the sea bed, and vibrations induced by forces on the equipment are possible explanations. Non-propagating turbulent pressure fluctuations, termed pseudosound, can mask ambient noise, especially in highly energetic environments suitable for tidal energy development. A statistical method identifies periods during which changes in the mean and standard deviation of the one-third octave band sound pressure levels are statistically significant and thus suggestive of pseudosound contamination. For each deployment, recordings with depth averaged tidal currents greater than 1 m/s are found to be contaminated, and only recordings with currents below this threshold are used in the subsequent ambient noise analysis. Mean total sound pressure levels (0.156 - 30 kHz) over all recordings are 117 dB re 1μPa. Total sound pressure levels exceed 100 dB re 1μPa 99% of the time and exceed 135 dB re 1μPa 4% of the time. Commercial shipping and ferry traffic are found to be the most significant contributors to ambient noise levels at the site, with secondary contributions from rain, wind, and marine mammal vocalizations. Post-processed data from an AIS (Automatic Identification System) receiver is used to determine the location of ships during each recording. Referencing 368 individual recordings with the distance between the ferry and the site obtained from AIS data, the source level of the ferry is estimated to be 179 ± 4 dB re 1μPa at 1m with a logarithmic spreading loss coefficient of 18.
Ambient noise level
Sound energy
Ambient pressure
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