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Peng, Dandan, and 彭丹丹. "Compact environmental noise absorber." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/209491.
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With the development of the industry and the society, noise pollution becomes increasingly severe, especially in large cities. Generally, there are three major noise sources, namely industrial noise, traffic noise and community noise. In response, several measurements have been developed to achieve effective noise control. Examples of noise control methods are reduction of noise at source and abatement of noise during the transmission. Since noise sources are more difficult to control, and sometimes already fixed, noise control during sound transmission is more broadly applied. Traditional passive noise control techniques include Helmholtz resonators and noise absorption materials like felt, glass mineral. The sound absorption materials (SAM) are found to be efficient in attenuating noise in high frequency domain, but their performance at low frequencies is quite poor. On the other hand, the Helmholtz resonator works perfect at any target frequency but suffers from its narrow absorption bandwidth, so that it’s only effective within a limited frequency band.
As an innovative solution to passive noise control problem, micro-perforated panel absorber (MPPA) has attracted great interest in recent years. It turns out to be a competitive alternative to sound absorption materials and Helmholtz resonator. The parallel and series arrangement of MPPAs backed with cavities of different depths allows them to obtain decent noise absorption performance over a relatively broad frequency range. However, the performance of MPPA is restricted by its volume, as large volume is demanded for decent low-frequency absorption, which is also the case for noise absorption materials.
In this thesis, a potential way to improve the low-frequency performance of the MPPA without occupying extra volume is proposed and implemented to tests. The focus is the adjustment of speed of sound and it is beneficial in different applications such as the following. In low frequency noise control, the size of the absorber in at least one dimension is often related to the wavelength and it is often too long. With a reduced speed of sound one can reduce this size while keeping the overall volume constant. Along this line of thinking, the effect of cavity configuration on its acoustic properties is investigated by two steps. Firstly, the property of a waveguide consisting of several identical elements is studied. The number of element is chosen to magnify the effect of the configuration. It turns out the irregularity of the duct shape can slow down the speed of sound of the plane wave by increasing the acoustic mass. Secondly, the absorption performance of an MPPA backed with an irregular cavity is evaluated. The shape of the cavity is the same as the element in the first step. In advance, the parallel arrangement of two MPPAs backed with irregular cavities is investigated, in order to look into the effect of cavity shape on inter-resonator interaction. The final results indicate that cavity design is an effective method to enhance the noise absorption performance of the MPPA arrays in the low-frequency domain.published_or_final_version
Mechanical Engineering
Master
Master of Philosophy
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Miksis-Olds, Jennifer L. "Manatee response to environmental noise /." View online ; access limited to URI, 2006. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3225323.
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Alberola, Javier. "Predicting variability in environmental noise measurements." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414693.
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Halin, Niklas. "A Shield against Distraction from Environmental Noise." Doctoral thesis, Högskolan i Gävle, Miljöpsykologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-22956.
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Working in noisy environments can be detrimental to cognitive performance. In order to perform well people have to find a way to attenuate distraction. This thesis aimed to study the balance between distractibility and task demands in the context of office-related tasks as a means by which to better understand how people in the work environment are influenced by environmental noise. In Report 1, 2 and 3 higher focal-task difficulty was achieved by manipulating the readability of the text that participants were asked to read (i.e. either displaying the text in hard-to-read font or by masking it with static visual noise). The results of Report 1 and Report 2 showed that background speech impaired performance on proofreading and memory for written stories respectively compared to silence, but only when the focaltask difficulty was low, not when it was high. In Report 3 it was shown that background speech, road traffic noise, and aircraft noise impaired performance on text memory compared to silence, but again, only when focal-task difficulty was low. In Report 4 it was tested whether higher cognitive load on the focal task would reduce peripheral processing of a to-be-ignored background story. The results of Report 4 showed that participants in the low-load condition recalled more of the information conveyed in the to-be-ignored background story compared to participants in the high-load condition. It was also investigated whether individual differences in working memory capacity (WMC) would influence participants’ memory for written stories (Report 2) and incidental memory of the to-background story (Report 4) differently depending on task demand. The results showed that individuals scoring high on the WMC-test were less distracted by background speech in the easy-to-read font condition (Report 2), and recalled less of the information in the to-be-ignored background story in the low-cognitive load condition (Report 4) compared to individuals that scored lower on the WMC-test. These relationships were not found in the hard-to-read font condition in Report 2, or in the high-cognitive load condition in Report 4. Taken together, these results indicate that higher focal-task difficulty can shield against the detrimental effect environmental noise on performance on office-related tasks. Moreover, it shows that higher focal-task difficulty can help individuals with low-WMC to reach a level of performance that is similar to that of high-capacity individuals.Människor som arbetar inom den byggda miljön (t.ex. kontor eller skolor) är ofta exponerade för olika typer av miljöljud (t.ex. bakgrundsprat, vägtrafiks- eller flygplansbuller) som kan ha en negativ inverkan på deras förmåga att prestera på kognitiva uppgifter (t.ex. läs- eller skrivuppgifter). För att kunna prestera behöver de som arbetar inom den byggda miljön hitta ett sätt att minska hur distraherade de blir av bakgrundsbuller när de arbetar med kontorsrelaterade uppgifter (t.ex. korrekturläsning eller minne för text). Syftet med denna avhandling var att studera balansen mellan distraktion och koncentrationskrav på arbetsuppgiften som ett sätt att undersöka vilken inverkan bakgrundsbuller i arbetsmiljön har på människors förmåga att prestera på kontorsrelaterade uppgifter. I Rapport 1, 2 och 3 manipulerades koncentrationskravet på arbetsuppgiften genom att göra texten mer svårläslig (d.v.s. antingen använda ett mer svårläsligt teckensnitt eller genom att maskera texten med ett visuellt brus). Resultaten på Rapport 1 och 2 visade att bakgrundsprat försämrade prestationen på ett korrekturläsningstest och ett textminnestest jämfört med en tyst betingelse, men bara när texten var lättläslig och inte när den var svårläslig. Rapport 3 visade att bakgrundsprat, vägtrafikbuller och flygplansbuller försämrade prestationen på ett textminnestest jämfört med tystnad, men återigen, bara när texten var lättläslig och inte när den var svårläslig. I Rapport 4 undersöktes om ökad kognitiv belastning på en arbetsuppgift skulle minska hur mycket information av ett bakgrundsprat (d.v.s. en berättelse om en fiktiv kultur) som deltagarna kunde återge trots att de blivit instruerade att ignorera det som sades i bakgrunden. Resultatet visade att deltagarna i betingelsen med låg kognitiv belastning kom ihåg mer av informationen från bakgrundsberättelsen jämfört med deltagarna med hög kognitiv belastning. Denna avhandling undersökte också sambandet mellan individuella skillnader i arbetsminneskapacitet och storleken på hur distraherad individen var av bakgrundsprat (Rapport 2), samt sambandet mellan arbetsminneskapacitet och hur mycket individen mindes av det bakgrundsprat de blivit instruerade att ignorera (Rapport 4), och om dessa samband influerades olika beroende på koncentrationskravet på arbetsuppgiften. Resultatet i Rapport 2 visade att individer med hög arbetsminneskapacitet blev mindre distraherade av bakgrundspratet jämfört med individer med låg arbetsminneskapacitet på prosaminnestestet, men bara när texten var lättläslig, inte när den var svårläslig. Rapport 4 visade att i betingelsen med låg kognitiv belastning kom de med hög arbetsminneskapacitet ihåg mindre av bakgrundsberättelsen jämfört med individerna med låg arbetsminneskapacitet, men när den kognitiva belastningen var hög var det ingen skillnad i hur mycket deltagarna kom ihåg av bakgrundsberättelsen mellan individer med hög och låg arbetsminneskapacitet. Sammanfattningsvis visar resultaten att ökat koncentrationskrav på en arbetsuppgift, genom att öka svårighetsgraden (t.ex. genom att använda ett mer svårläsligt teckensnitt), kan skydda mot den negativa inverkan som bakgrundsbuller har på arbetsuppgifter som liknar de människor arbetar med på kontor. Vidare visade resultaten att ökade koncentrationskrav på arbetsuppgiften kan hjälpa individer med låg arbetsminneskapacitet att prestera i paritet med individer med hög arbetsminneskapacitet när arbetsuppgiften utförs i bakgrundsprat.
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Johansson, Marcus. "An indicative case-control study of noise perception due to environmental noise sources." Thesis, KTH, Marcus Wallenberg Laboratoriet MWL, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280546.
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The subject of the thesis was proposed by the acoustic consultancy firm Brekke & Strand, which is of relevance for their additional understanding and development of services and contribution to robust solutions. The aim with this thesis is to give indicative results and to dig deeper into the relation between environmental noise and the perception of the same, specially focusing on construction related noise but also permanent noise sources that originates from infrastructure. The area of interest to evaluate the study is a central location in Stockholm, specifically around Slussen.The importance of a study within this field is vital, especially when considering possible negative health effects that can be related to the perceived noise exposure. With that background it is worth to consider the amount of healthy-life-years lost in Europe each year, which is assumed to be one million. The correlation between lost life years and noise is one of many, but it is also proven to be a catalyst when it comes to stress related or cardiovascular diseases. For instance, if one is living closer than 50 meters from a major road the risk can be four times higher to be annoyed, which in extension can be coupled to the diseases mentioned above.The practical implementation of the study is conducted with a survey and field measurements, with a psychoacoustical perspective and within the frames of a case-control study. Partially this includes to inform the participants of the study at different stages regarding construction noise. The provided information, survey and field measurements aims to be a substantial part of the evaluation regarding the perceived noise whether it is due to construction work, infrastructure or other stochastic sources.The result is presented and distinguished based on distance to noise source, differentiated by gender as well as which type of source that tends to be most annoying. The implemented ranking is displayed as the ICBEN score of each category or source which aims to measure the perceived impact. Even though the results are indicative, the conclusion yields an information dependency as well as a noise source dependency. Further on, the result yields an interesting pattern between genders where women tend to be more disturbed by construction- and other-noise, whereas men tend to be more disturbed by rail- and road-noise.Ämnet för uppsatsen föreslogs av akustiskkonsultföretaget Brekke & Strand, vilket är av relevans för deras ytterligare förståelse och utveckling av tjänster och bidrag till robusta lösningar. Syftet är att ge vägledande resultat och gräva djupare i förhållandet mellan samhällsbuller och uppfattningen av detsamma, med särskilt fokus på konstruktionsrelaterat buller men också permanenta bullerkällor som härstammar från infrastruktur. Studien och utvärderingen av den samma har fokuserats till Slussenområdet i centrala Stockholm.Betydelsen av en studie inom detta område är avgörande, särskilt när man överväger eventuella negativa hälsoeffekter som kan relateras till den upplevda bullerexponeringen. Med den bakgrunden är det värt att ta hänsyn till hur många hälsosamma levnadsår som går förlorade i Europa varje år, vilket antas vara en miljon. Korrelationen mellan förlorade levnadsår och buller är en av många, men det har också visat sig vara en katalysator när det gäller stressrelaterade eller hjärt- och kärlsjukdomar. Om man till exempel bor närmare än 50 meter från en huvudväg kan risken vara fyra gånger högre för att bli störd och påverkad av buller, vilket i förlängning kan kopplas till ovan nämnda sjukdomar.Det praktiska genomförandet av studien utförsmed en enkätundersökning, fältmätningar,med ett psyko-akustiskt perspektiv och inom ramen för en fallkontrollstudie. Detta inkluderar delvis att informera deltagarna i studien i olika stadier beträffande konstruktionsrelaterat buller. Den tillhandahållna informationen, undersökningen och fältmätningarna syftar till att vara en väsentlig del av utvärderingen av det upplevda bullret oavsett om det beror på byggnadsarbete, infrastruktur eller andra stokastiska källor.Resultatet presenteras och skiljer sig utifrån avstånd till bullerkälla, uppdelat efter kön samt vilken typ av källa som tenderar att vara mest irriterande. Den implementerade rangordningen visas som ICBEN-skalan för varje kategori eller källa, som syftar till att mäta den upplevda effekten. Även om resultaten är vägledande så visar resultaten ett informationsberoende samt ett bullerkällaberoende. Vidare ger resultatet ett intressant mönster mellan könen, där kvinnor tenderar att bli mer störda av konstruktions- och andra-bullerkällor, medan män tenderar att bli mer störda av järnvägs- och väg-buller.
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Wright, Philip. "Extending the scope of unattended environmental noise monitoring." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320714.
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Joynt, Jennifer L. R. "A sustainable approach to environmental noise barrier design." Thesis, University of Sheffield, 2005. http://etheses.whiterose.ac.uk/12880/.
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This thesis recognises the implicit shortfalls in the current methods of noise barrier development. An holistic and integrative methodology was devised, which can be potentially incorporated into general practise, without the unnecessary burdens of excessive cost and environmental impacts. In essence the thesis defines, 'a sustainable approach to environmental noise barrier design'. The importance of sustainability as a key determinant of a noise barrier's success is demonstrated through the impacts of public participation on the acceptance of a noise barrier. This was achieved through the triangulation of a grounded theory, formulated through the qualitative analysis of a real case study and then tested quantitatively on a larger representative sample. The theory explored the impact of ineffective public participation on the perceived success of a noise barrier. Noise maps were developed for the comparison of subjective opinions with objective facts. This also illustrated how this technology can be manipulated to focus public participation, and increase success. Demonstrating the utility of this growing resource beyond its current scope. A methodology for assessing the embodied impacts of noise barrier structures was also devised. By addressing the current lack of availability of a specific model, the means of choosing a noise barrier based on sustainable assets was revealed. Finally, the thesis concluded with a laboratory experiment, which utilised a RAVE facility and revealed the extent to which preconceptions play a role in the perception of a noise barriers' effectiveness. Revealing that regardless of which noise barrier is presented, that preconceptions of a materials' ability to attenuate noise are imbedded. The thesis contributed to several areas through the illustration of a sustainable approach to environmental noise barrier design. The methods highlighted, demonstrate how those responsible for building noise barriers, can improve the acceptance by the public and decrease the environmental impacts associated with the construction of these structures.
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Chandler-Wilde, S. N. "Ground effects in environmental sound propagation." Thesis, University of Bradford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384241.
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Haikonen, Kalle. "Underwater radiated noise from Point Absorbing Wave Energy Converters : Noise Characteristics and Possible Environmental Effects." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-235016.
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The conversion of wave energy into electrical energy has the potential to become a clean and sustainable form of renewable energy conversion. However, like all forms of energy conversion it will inevitably have an impact on the marine environment, although not in the form of emissions of hazardous substances (gases, oils or chemicals associated with anticorrosion). Possible environmental issues associated with wave energy conversion include electromagnetic fields, alteration of sedimentation and hydrologic regimes and underwater radiated noise. Underwater noise has the potential to propagate over long distances and thus have the potential to disturb marine organisms far away from the noise source. There is great variation in the ability to perceive sound between marine organisms, one sound that is clearly audible to one species can be completely inaudible to another. Thus, to be able to determine potential environmental impact from WECs associated with underwater noise, the noise radiated from the WECs must be known. This thesis presents results from studies on the underwater radiated noise from four different full-scale WECs in the Lysekil Wave Power Project. Hydrophones were used to measure the underwater radiated noise from operating point absorbing linear WECs. The main purpose was to study the radiated noise from the operating WECs with emphasis on characteristics such as spectrum levels, Sound Pressure Level (SPL), noise duration and repetition rate. This to be able to determine the origin of the noise and if possible, implement design changes to minimize radiated noise. The results identified two main operational noises (transients with the bulk of the energy in frequencies <1 kHz). The SPL of the radiated noise fluctuated significantly, depending on wave height. Broadband SPLrms of the measurements ranged between ~110 dB and ~140 dB re 1 µPa and SPLpeak of specific noises ranges between ~140 and ~180 dB re µPa. Audibility was estimated range from 1km to 15 km depending critically on species and on assumptions of propagation loss. The noise is not expected to have any negative effects on behaviour or mask any signals, unless in the vicinity (<150m) of the WECs in significant wave heights. No physical damage, even in close vicinity are expected on either fish or marine mammals. Having the aim to have as little impact on the environment a possible, these studies are important. This way precautions can be implemented early in the technical development of this kind of renewable energy converters. The benefits from the WECs the Lysekil wave power project are believed to outweigh possible environmental impacts due to underwater radiated noise.Vid avhandlingens tryckläggning upptäcktes inte att tidpunkt för disputation var fel.
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Ibrahim, Hatem Galal Abdel-Azim. "The development of an environmental noise decision support system." Thesis, University of Liverpool, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399063.
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The methodology of noise control exists to solve many noise problems. The most cost effective methods of controlling noise are those that can employed in advance to prevent any potential noise problem occurring. The majority of architects are overlooking to consider any noise problem during the process of the site planning. This is because the existing methods need long procedure to arrive at the required conclusion regarding the noise performance of the site. The existing methods depend of predicting the noise level at the reception point that effected by the noise source. This depends on many variables, including the distance from source; the propagation effects include screening and ground attenuation ...etc. The second stage comes to establish the kind of the building that the receiver will use. At this stage, the noise control expert can establish the required noise performance to solve the problem. Another complicated procedure comes by using the methodology of the noise control, which branches to many options. The chosen option depends on a certain priority and the condition of the architect. On the basis of the above, the thesis concerns with developing another method using the existing techniques, but to use by the architects or the novice users. This method gives the prediction of the noise level at the reception point, establishing the required noise performance and finally gives the suitable advice to solve the problem. The Artificial Intelligence (AI) techniques in general and Expert System (ES) in particular have been employed to develop this method. The most important part in this technique is the knowledge base that will be used to fulfil the desired objective This knowledge has to proceed within many stages, which called knowledge acquisition process. This process consists of 5 main stages, which concerns with identifying the objectives of the system with drawing a relationship between the different factors that effect the desired conclusion. This knowledge should be taken to establish the main concept that will be used to be represented in an expert system. The next stage comes to formalise the collected knowledge followed by the implementation stage and finally the evaluation of the system.
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Atmoko, Hidajat. "Development of active control systems for controlling environmental noise." Thesis, University of Huddersfield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247466.
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SUMME, LORI ANN. "Noise Reduction in Digital Hearing Aids Using Environmental Sounds." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1052327314.
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Hagood, Timothy J. "A Higher Education Site's Environmental Noise Impacting the Neighborhood." University of Toledo Health Science Campus / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=mco1388768193.
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Harriet, Sorrel. "Application of auralisation and soundscape methodologies to environmental noise." Thesis, University of York, 2013. http://etheses.whiterose.ac.uk/4724/.
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The thesis investigates how auralisation and qualitative research methodologies developed in the field of soundscape research, may be applied to the issue of environmental noise in urban areas. The project brings together research and assessment methodologies from traditionally distinct areas in acoustics, and attempts to develop a multidisciplinary approach to solving noise related urban design problems. Within this process, the author also explores the theory that part of a sustainable solution to noise annoyance lies in challenging negative attitudes to noise, particularly in urban environments, where attempts to reduce sound pressure levels are either not feasible or inappropriate. To demonstrate the application of the approach, a case-study is presented involving the auralisation and subjective evaluation of a real-world soundscape before and after the insertion of a sonic crystal noise barrier. The results of the case-study suggest that, with minimal adaptation, certain soundscape assessment methodologies are compatible with virtual acoustic environments. This leads to the conclusion that, using the virtual assessment methodology, one is able to predict with reasonable accuracy the impact of various physical types of noise intervention on the perceived sound quality in urban environments prior to their construction. The author also argues that a greater awareness and appreciation for the multiplicity of sound in urban environments might, in conjunction with sustainable noise control strategies, over more long-term benefits to society than over-speculation concerning the adverse effects of noise.
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Lu, Cherie Hsiao-Ying. "Social welfare impacts of environmental charges on commercial flights." Thesis, Cranfield University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341016.
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Alvarsson, Jesper J. "Stress recovery during exposure to natural sounds and environmental noise." Thesis, Stockholm University, Department of Psychology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-27894.
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Research suggests that physiological stress reactions may be reduced by visual impressions from natural environments as compared to urban or built-up environments. The present experiment tested whether similar effects might be found by auditory stimulation. Forty university students were tested in an experiment with four consecutive recovery sessions after stressful mental arithmetic tests. The independent variables were type of sound during recovery. The sound was either a natural sound environment (sounds from water and birdsong, at 50 dBA), or three types of noisy environments (traffic noises at 50 or 80 dBA or ambient background sound at 40 dBA). The main dependent variables were physiological recovery from stress, as measured by decrease in heart rate (HR) and skin conductance level (SCL) after the stressful arithmetic test. The main result was that SCL reduction was faster during nature sounds than during the various noises. For HR, no systematic effects of experimental sounds were found. The result for SCL lends some support the hypothesis that exposure to natural sounds facilitate physiological stress recovery.
Sarcade
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Petchey, Owen Leonard. "The effect of environmental noise on population and community dynamics." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267617.
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Ruan, Ruoling, and 阮若琳. "Environmental noise and non-auditory health impacts in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206958.
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The magnitude of noise pollution is fast-growing worldwide. Environmental noise has been linked with several non-auditory health impacts, including annoyance, sleep disturbance, cardiovascular diseases and impaired cognitive performance. Also, environmental noise exposure is associated with increased reported psychological symptoms, prolonged healing time of patients and poorer performance of staff in hospitals. Hong Kong has been suffering from environmental noise for years, especially transportation noise, but lack of relevant local studies to support public health intervention. This review is attempted to summarize three governmental study reports and overseas studies on the relationship between noise and non-auditory effects. Also data on noise complaints will be briefly analysed as a supplement. It is ascertained that noise pollution and noise-induced annoyance and sleep disturbance are prevalent in Hong Kong. Also, noise mapping and subjective auditory effect scales are already available. Noise complaint level in Hong Kong is generally lower than levels in London and New York City, but is probably underestimated. Future studies are needed to emphasize on noise exposure in particular areas and vulnerable populationspublished_or_final_version
Public Health
Master
Master of Public Health
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Moeller, Michael M. Jr. "Noise environment characterization in military treatment facilities." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/48995.
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Hospital sound environments are complex and hard to understand. One of the most important factors in these environments is the effective communication between staff members in regards to patient care and successful communication depends in part on the hospital’s sound environment. In this study, objective sound measurements as well as occupant perceptive data were collected at three hospitals. Sound pressure levels; including maximum, peak, minimum and equivalent levels were recorded in these hospitals, in addition to active impulse response measurements. Acoustic descriptors of the sound environment such as spectral content, level distributions, energy decay and temporal patterns were examined. The perception of the hospital soundscape (sound environment) was evaluated through surveys of the staff, patients and visitors to units. It was found that noise levels in all patient rooms and work areas were significantly higher than guidelines laid out in previous literature and by professional organizations. This work contributes to the field by broadening the metrics used to quantify hospital acoustic environments. In addition, this work added to the field by providing the most rigorous acoustic field measurement set published to date. This was done to create an accurate portrayal of the hospital soundscape environment.
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Ambreen, Iqbal. "Impact of traffic noise pollution on the environment." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31261188.
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Barros, David Alexandre Lampreia. "Analise e caracterização do ruído ambiente urbano. Cidade de Lisboa - Bairro habitacional." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4030.
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Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaThe work of this dissertation focuses essentially on matters related to the areas of environmental acoustics – noise and discomfort to the urban population. Noise is a source of noise pollution, which is a combination of various sound sources, from commercial activities and services, religious spaces, construction, vehicle traffic, human activities, etc. This raises the level of urban noise and contributes to the emergence of unpleasant sound environments increasingly. With the evolution of society, noise is considered one of the most common environmental problems, degrading the quality of life and the environment. The legislation and international regulations have allowed the quantification by means of noise maps and acoustical prediction, where the legal authorities can view and plan interventional measures for a proper planning of the urban places. This case study describes the noise in the urban environment in the city of Lisbon, more specifically, a typical residential area of the city – Benfica – Igreja de Benfica – Rua dos Arneiros. An environmental noise analysis, through the acquisition levels of sound pressure and frequency spectra in bands 1 / 3 octave, continuously under a period of 7 (seven) days during the month of May 2011. The results showed the characteristic noise of a residential zone of the city of Lisbon, as well as identified what are their main sources. The information drawn from this study may serve as a basis for development and planning of cities in relation to acoustic comfort.
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Pathak, Khanindra. "Modelling and prediction of environmental noise levels near mechanised surface mines and quarries." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/8776.
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Tuffy, Mark. "The removal of environmental noise in cellular communications by perceptual techniques." Thesis, University of Edinburgh, 2000. http://hdl.handle.net/1842/1379.
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This thesis describes the application of a perceptually based spectral subtraction algorithm for the enhancement of non-stationary noise corrupted speech. Through examination of speech enhancement techniques, explanations are given for the choice of magnitude spectral subtraction and how the human auditory system can be modelled for frequency domain speech enhancement. It is discovered, that the cochlea provides the mechanical speech enhancement in the auditory system, through the use of masking. Frequency masking is used in spectral subtraction, to improve the algorithm execution time, and to shape the enhancement process making it sound natural to the ear. A new technique for estimation of background noise is presented, which operates during speech sections as well as pauses. This uses two microphones placed on opposite ends of the cellular handset. Using these, the algorithm determines whether the signal is speech, or noise, by examining the current and next frames presented to each microphone. This allows operation in non-stationary conditions, as the estimation is calculated for each frame, and a speech pause is not required for updating. A voting decision process decides the presence of speech or noise which determines which microphone the estimation is calculated from. The importance of an accurate noise estimate is highlighted with a new technique to reduce the effect of musical noise artifacts in the processed speech. This is a classic drawback of spectral subtraction techniques, and it is shown, that the trade off between noise reduction and speech distortion can be extended by this process. A new method for dealing with musical noise is described, which uses a combination of energy and variance examination of the spectrogram to segregate potential musical noise from desired speech sections. By examination of the spectrogram points surrounding musical noise sections, perceptually relevant values replace the corruption leading to cleaner enhanced speech. Any perceptual speech system requires accurate estimates of the clean speech masking thresholds, to prevent noisy sections being passed through the enhancement untouched. In this thesis, a method for the calculation of the estimated clean speech masking thresholds is derived. Classically, this requires an estimation of the clean speech before the thresholds can be derived, but this results in inaccuracy due to the presence of musical noise and spectral nulls. The new algorithm examines the thresholds produced by the corrupted speech, and the background noise, and from these determines the relationship between the two, to produce an estimate of the clean thresholds, with no operation performed on the actual speech signal. A discrepancy is found between the results for male and female speech, which, by examination of the perceptual process, is shown to be due to the different formant positions in male and female speech. Following the development of these parts, the entire enhancement algorithm is tested on a range of noise scenarios, using male and female speech. The results show, that the proposed algorithm is able to provide adequate performance in terms of noise reduction and speech quality.
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Sheng, Nan. "Prediction and 3D Visualization of Environmental Indicators: Noise and Air Pollution." Thesis, KTH, Geodesi och satellitpositionering, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91351.
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Environmental problems such as noise and air pollution are increasingly catching people’s attention in recent years owing to the industrialization and urbanization all over the world. Therefore it is important to develop effective methods to present information on noise and air pollution to the public. One feasible approach is to carry out prediction based on traffic data and make noise and pollution maps. GIS is a powerful tool for prediction since its spatial analysis function could be used in analysis and calculation. In addition the available GIS platforms also provide visualization functions to display the analysis results in variety of forms, in both 2D and 3D. This thesis uses noise and air pollution as examples to study how to predict noise and pollution from traffic data and how to visualize the predicted pollution information in 3D with the help of the existing visualization technology. Therefore, the thesis has two objectives. The first objective is focused on prediction of noise and air pollution using existing prediction models based on vehicle speed and traffic volume data. The original spatial road network dataset with traffic information was integrated with GIS and analysis and calculations were carried out. Road Traffic Noise-Nordic Prediction Method is used for predicting traffic noise while ARTEMIS model and OSPM model are applied for traffic air pollution. All analysis and calculations were carried out on virtual receiver points generated on ground surface and over building facades at different heights. The second objective is focused on 3D visualization of the predicted traffic noise and air pollution in ArcScene, Google Earth as well as X3D respectively. In ArcScene the virtual receiver points were visualized in their actual position with different colors representing noise or air pollution level. Then KML files were created from the point shapefiles and imported into Google Earth to show the noise and air pollution level in the virtual city available in Google Earth. Finally one layer of point shapefile was selected as an example to give the 3D scene in X3D. The selected layer of points was first interpolated into a continuous surface and converted into contours. Three types of models were developed in this part. First is to visualize contours in 3D using both colors and heights to show the noise or air pollution levels. Next the interpolated surface was segmented into scattered cells displayed also in colors and heights both representing pollution intensity. The last one is using 3D bars to show noise or air pollution in colors and lengths. The prediction results shows that the either noise or air pollution in the north part of central Stockholm is much more serious than in south part and the most polluted area appear along the highways. In the same area the pollution levels vary in different heights. The 3D visualization in ArcScene and Google Earth could clearly present the differences. However, so far the visualization in X3D only gives 2D information in 3D, which means although the 3D scenes were created, the height only noise or air pollution on the specific height could be represented. The real 3D representing is still need to be studied.VisuCity
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Felizardo, Francis Camomot. "Ambient noise and surface wave dissipation in the ocean." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12460.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1993.Includes bibliographical references (leaves 189-201).
by Francis C. Felizardo.
Ph.D.
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Berry, Maresi (Maresi Ann) 1969. "Graphical method for airport noise impact analysis." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50429.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1998.Includes bibliographical references (p. 99-102).
by Maresi Berry.
S.M.
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Watkins, Alexandra. "Sonic Apartheid: ecoracism, apartheid geographics and noise pollution in Cape Town's Blikkiesdorp." Master's thesis, University of Cape Town, 2020. http://hdl.handle.net/11427/32488.
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In Sonic Apartheid: Ecoracism, Apartheid Geographies, and Noise Pollution in Cape Town's Blikkiesdorp, Alexandra Downing Watkins begins a project of mapping geographies of dispossession and abandonment in Blikkiesdorp (Afrikaans for "Tin Can Town"), a Temporary Relocation Area on the margins of Cape Town created in 2007 following a wake of mass evictions for the 2010 World Cup. After being created as a "temporary" solution, Blikkiesdorp remained a site of abandonment where evicted peoples, refugees, and other "undesirables" were sent to live. Seven years later, the City of Cape Town and the Airports Company of South Africa signed a Memorandum of Understanding agreeing to realign one of the airport's runways, which would serve to relocate the community. Following the story of strategic organising by the Blikkiesdorp community to be included in the Environmental Impact Assessment that was being instrumentalized to further displace them, this work examines the community's struggle against conditions of abandonment through complicating the division of humans and the environment. This project engages with the mechanics of bio-, necro-, and geontopower, in contemporary South African environmental governance as an afterlife of apartheid spatial planning. The project features environmental research that was completed in cooperation with community members who shared their experiential environmental knowledge through interviews and diary entries as well as compiling decibel readings of excessive noise pollution. This data along with noise pollution diaries, photographs, and interviews has been compiled and placed in a digital archive in the form of an open-source ArchGIS Story Map. Combining theory and research contributed by the Blikkiesdorp community with the contemporary theoretical language of new materialism and critical race theory, this work engages with the porosity of bodies, the co-imbrication of bodies and landscape, how the creation of an "alternative social project" can serve to disturb and resist evidence-based technoscience and processes of ecoracist governance.
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Levine, Matthew Jason. "A framework for technology exploration of aviation environmental mitigation strategies." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54437.
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The goal of this thesis was to develop a framework for modeling relevant environmental performance metrics and objectively simulating the future environmental impacts of aviation given the evolution of the fleet, the development of new technologies, and the expansion of airports. By exchanging fidelity for computational speed, a screening-level framework for assessing aviation's environmental impacts can be developed to observe new insights on fleet-level trends and inform environmental mitigation strategies. This was accomplished by developing per class average ``generic-vehicle" models that can reduce the fleet to a few representative aircraft models for predicting fleet results with reasonable accuracy. The method for Generating Emissions and Noise, Evaluating Residuals and using Inverse method for Choosing the best Alternatives (GENERICA) expands a previous generic vehicle formulation to additionally match DNL contours across a subset of airports. Designs of experiments, surrogate models, Monte Carlo simulations, and ``desirability" scores were combined to set the vehicle design parameters and reduce the mean relative error across the subset of airports. Results show these vehicle models more accurately represented contours at busy airports operating a wide variety of aircraft as compared to a traditional representative-in-class approach. Additionally, a rapid method for assessing population exposure counts was developed and incorporated into the noise tool, and the generic vehicles demonstrated accuracy with respect to population exposure counts for the actual fleet in the baseline year. The capabilities of the enabled framework were demonstrated to show fleet-level trends and explore placement of new runways at capacity constrained airports.
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Gordon, Shira D. "Environmental Interference and Seismic Communication in Wolf Spiders." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1281459002.
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Summe, Lori Ann. "Noise reduction in digital hearing aids with a background of environmental sounds." Cincinnati, Ohio : University of Cincinnati, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1052327314.
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Wichers, Michiel. "Ferramentas para o prognóstico do ruído ambiental em pedreiras." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3134/tde-28112017-091535/.
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Pedreiras se destacam pela intensa relação com as comunidades situadas em seu entorno, uma vez que a proximidade aos centros consumidores configura importante vantagem competitiva, por possibilitar uma redução nos custos de transporte. Essa proximidade, entretanto, também intensifica os impactos ambientais percebidos pela população. Dentre os impactos ambientais negativos destaca-se o ruído, gerado pela maior parte das atividades desenvolvidas em pedreiras. Um adequado prognóstico dos níveis de pressão sonora, durante a fase de licenciamento ambiental, permite minimizar o número de moradores expostos a esse incômodo. Um programa de monitoramento dos níveis de ruído constitui também uma ferramenta para indicar em quais locais do entorno as comunidades podem estar expostas a níveis de pressão sonora superiores aos padrões normativos. Para realizar um prognóstico dos níveis de ruído parte-se da potência sonora dos equipamentos. Esta informação, entretanto, não está disponível para a maior parte dos equipamentos utilizados em pedreiras. Para o prognóstico dos níveis de ruído existem pacotes de software revendidos pelos principais fabricantes de sonômetros que, entretanto, possuem preços elevados, além de não possuírem um banco de dados com potências sonoras para equipamentos de pedreiras. Dessa forma, são raros os estudos ambientais em pedreiras que contam com um adequado prognóstico ambiental de ruído. Neste estudo foram selecionadas três pedreiras de pequeno, médio e grande porte para levantamentos de campo. Os três empreendimentos mineiros apresentam conflitos com as comunidades relacionados com o ruído. Por meio de medições de níveis de pressão e de intensidade sonoras, foram determinados os níveis de potências sonoras de equipamentos empregados na lavra e na britagem para essas três pedreiras. Existem na bibliografia diversos modelos de atenuação do ruído com a distância, incorporando fatores como barreiras, reflexões no solo, presença de vegetação, absorção pelo ar, parâmetros meteorológicos, entre outros. Estes modelos variam em complexidade, em quantidade de informações de entrada necessárias e em precisão. Foram comparados os resultados de três modelos: o modelo que considera apenas a divergência geométrica das ondas sonoras, o modelo da OCMA (Oil Companies Materials Association) e o modelo da norma ISO 9613. O modelo da norma ISO 9613, mais complexo, requer mais dados de entrada, mas fornece, por outro lado, resultados consideravelmente mais precisos que os outros dois modelos. Desenvolveu-se um software, denominado PROGNOISE, baseado na norma ISO 9613, que representa uma alternativa gratuita aos softwares comerciais e que, em conjunto com as potências sonoras das máquinas e equipamentos determinadas neste trabalho, formam uma ferramenta acessível para o prognóstico do ruído ambiental em pedreiras.Quarries stand out by the intense elationship with communities located in its surroundings. The proximity of these mines to consumer centers constitutes an important competitive advantage, allowing a reduction in transportation costs. This proximity, however, also intensifies the environmental impacts perceived by the population. Among the negative environmental impacts, we can highlight noise generated by most activities in quarries. A proper prognosis of sound pressure levels during the environmental licensing phase minimizes the number of residents exposed to this nuisance, providing indication of areas where high levels are expected and required to be incorporated into the boundaries of the enterprise, the locations indicated for deployment of the processing facilities aiming at smaller spread of noise for residential areas, or indicating locations for implementation of noise barriers. An environmental noise monitoring program is also a tool to indicate locations in the surrounding communities that may be exposed to sound pressure levels exceeding the regulatory standards. A forecast of noise levels starts with the sound power of equipment. This information, however, is not available for most of the equipment used in quarries. There are software packages resold by leading sound level meter manufacturers for prognosis of noise levels, which, however, have high prices, in addition to not having a sound power database for quarries. In this way, only few environmental studies for quarries have a proper environmental noise prognosis. In this study, we selected three quarries for field surveys: small, medium and large sized. These three quarries are facing noise conflicts with the community. The sound power levels of the main mining equipment used in quarries were determined through sound pressure levels. There are several noise forecasting models in the bibliography, incorporating factors such as barriers, reflections on the ground, presence of vegetation, air absorption and meteorological conditions, among others. These models vary in complexity, in amount of necessary input information, and precision. The results of three models were compared: a simple model considering only the geometric divergence of sound waves, the OCMA (Oil Companies Materials Association) model and the ISO 9613 standard model. While the ISO 9613 standard model requires more input data and is more complex, it provides on the other hand considerably more accurate results than the other two models. A software, called PROGNOISE, was developed based on the ISO 9613 standard, which represents a free alternative to commercial software and, together with the sound power of the machines and equipment determined in this study, form an accessible tool for the prognosis of environmental noise in quarries.
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van, Kempen Elise, Kamp Irene Van, Paul Fischer, Hugh Davies, Danny Houthuijs, Rebecca Stellato, Charlotte Clark, and Stephen Stansfeld. "Noise exposure and children's blood pressure and heart rate: the RANCH project." BMJ Publishing Group, 2006. http://hdl.handle.net/2429/854.
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Conclusions that can be drawn from earlier studies on noise and children’s blood pressure are limited due to inconsistent results, methodological problems and the focus on school noise exposure. This paper reports on a study investigating the effects of aircraft and road traffic noise exposure on children’s blood pressure and heart rate.
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Liu, Yuen-mei, and 廖婉薇. "Feasibility study of green noise barriers in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48543299.
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Hong Kong is a crowded city where pavements, lanes, hawker areas, trunk roads and highway are closely built. With heavy traffic flow on complex road networks, the noise barriers located in the urban centre usually adjacent to commercial centres and residential buildings. The design of noise barriers is therefore needed to be in harmony with the landscape of the neighbourhood. Different kinds of green noise barrier systems combined with soil and vegetation had been developed across Europe and the USA in recent years. It is believed that an effective controller of noise shall be visually attractive especially for residents who are adjacent to the roads. A number of noise barriers with vegetation were successfully implemented in European Countries. Nevertheless, these engineering techniques cannot be fully applied to Hong Kong due to the over-crowded living environment.
A well-designed green noise barrier system is the critical reason for successful application to sustain the vegetation and to insulate and absorb noise. The objective of this study to investigate different kinds of green noise barriers and come up with some guidelines for design consideration in order to optimize the green noise barriers. The study provides a thorough analysis of the available green noise barrier systems across the world, including a look at all the potentials benefits from environmental and socio-economics perspectives.
The pilot field measurement was conducted at Yeung Uk Road where green noise barriers located between a heavily travelled main road and residential area in Tsuen Wan, to measure the SPL and Leq noise levels to assess the effectiveness of the green noise barriers. No significant attenuation effect is observed on the green noise barrier which has to be attributed to the median placement and over-crowded urban environment.
Online questionnaires and interviews are conducted to investigate the effects of vegetation on the perception of green noise barriers. Results show that 78% of the respondents preferred vegetation rather than concrete (0.1%) and other materials. 77% like the aesthetics appearance of vegetation and 86% are willing to bear the cost. In general, 95% of the respondents agreed green noise barriers should be promoted in Hong Kong. The results assured that (1) vegetation on green noise barrier is aesthetically pleasing and mostly preferred; (2) people are willing to pay for green noise barrier for aesthetics; (3) aesthetic or vegetated screen is important in determining human response to noise which improved public perception of traffic noise due to visual and psychological relief.
The outcome of the study indicated that it is feasible to promote green noise barriers in Hong Kong, with the evidence of the potential benefits, technical experience and public support. It is also suggested that the living wall modular system is the best system which is suitable for the application in Hong Kong.published_or_final_version
Environmental Management
Master
Master of Science in Environmental Management
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Boutatis, Antonios 1974. "Noise aviation pollution in airports : the case of Boston Logan International Airport." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/84257.
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Michail, Antonios. "Environmental management of the logistic chain : with specific reference to ports and noise." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/55792/.
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The logistic chain has evolved from being a concept of integrated transport activity to that of a fully functioning, dynamic, and complex multi-component system with the primary function of delivering effective management of freight mobility. Whilst humanity is faced with the challenge of reducing the impact of transport on the environment without losing the benefits to society and economies, a holistic approach to the environmental management of the logistic chain emerges as a necessity. The thesis follows a multi-method and interdisciplinary, phased pathway in order to (1) assess the feasibility and practicability of delivering sustainable development through such a chain, (2) address the challenges inherent to its implementation, and (3) develop a model that guides the development and delivery of an environmental management system specifically focussed on the logistic chain. Following an environmental management based methodology, the significant environmental aspects of the logistic chain operations are identified and analysed. Focus is then placed on the major players in the chain (transport buyers, providers and operators) and, in particular, on selected practices that have the potential to improve chain environmental performance and guide the future trends of the sector's response. Seaports are selected for purposes of evaluation and validation of various options as they arguably represent the major and most complex of the logistic nodes in terms of intense intermodal and multi-actor interest. The evolution and trends in the field of integrated seaport area management are evaluated by specifically designed surveys and case studies. Similarly, noise is selected as a multi-source, trans-boundary and complex issue in order to examine the potential options for control of significant environmental aspects of the logistic chain. The feasibility of integrated noise management throughout the chain is assessed through the demonstration of available management response options. The results and the major observations are finally synthesised in order to propose a generic model suitable for addressing the challenges of integrated environmental management of the logistic chain.
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Gudmundson, Sara. "Species Responses to Environmental Fluctuations : impacts of food web interactions and noise color." Doctoral thesis, Linköpings universitet, Teoretisk Biologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-136840.
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Species constantly experience changes in their environmental conditions owing to natural or human induces reasons. Understanding how species respond to these fluctuations are important for ecology, especially given the ongoing climate change. Empirical studies have shown that species respond differently to the same disturbance. However, our knowledge of what create these differences in the environmental response is limited and in most cases based on studies focusing on single species. In this thesis, I have taken a theoretical approach and used dynamical models to investigate how the population dynamics of species are affected by species-species interactions and environmental fluctuations. In the first paper (Paper I) I investigated how a species respond to environmental fluctuations when isolated or embedded in a food web. The study showed that species-species interactions had an effect in temporally positively autocorrelated environments (red noise) but not in uncorrelated environments (white noise). This was owing to species following their equilibrium densities in red environments which in turn enabled species-species interactions to come into play. Red environmental variables are more prominent in nature than white. Thus, these results show the importance of using a food web approach when analyzing species response to environmental fluctuations. The most commonly discussed effect of climate change is an elevated mean temperature. This shift is expected to affect the growth rate of many species. However, there is no robust theory of how we should expect species in food webs to respond to a rise in temperature. In the second paper (Paper II) I defined and studied the dynamic rate of food webs (DR) acting analogously to single species growth rate. I found that the higher DR the easier for species population densities to follow their equilibrium over time. Both DR and noise color changed the temporal relationship between the population and the environmental noise. Thus, it is of major importance to take the scale of time into consideration when investigating species response to environmental fluctuations. Another important factor which affect population dynamics is species spatial distributions. Dispersal between subpopulations enable individuals to rescue or prolong the time to extinction for the population seen as a whole. In the third paper (Paper III), I investigated how species in food webs respond to environments that varies both in time and space and compared the results with the one from single species. I found that single species were stabilized by an increased dispersal rate independent of the noise color. Species-species interactions had an effect for some of the species in these landscapes. At red asynchronous noise, one resource species in each food web had a local minimum in stability at low dispersal rate. Here, dispersal decoupled local population dynamics and prevented species from tracking their equilibriums. At high dispersal rates, all resource species and their single species counterparts were stabilized by dispersal as local patch dynamics lost its importance. Environmental noise together with the spatial dimension does seem to explain much of the stability properties of species on our planet. However, natural ecosystems are much more complex and species rich than the food web models I have used so far. Theoreticians have previously had a hard time describing stable complex systems that survive environmental fluctuations. Thus, in my fourth and last project (Paper IV) I investigated how species population dynamics are affected by environmental fluctuations when embedded in larger food webs. These systems were built by connecting food web modules with periodic boundary conditions (PBC). The PBC method has previously helped physicists to understand the nature of waves and particles by removing the edges in systems. I found that food web size does not have to have a negative effect on food web stability. I showed that by removing the destabilizing effect of edges it is possible to describe large stable food webs, more similar to natural ecosystems. Overall, the research presented here give new insights into species responses to environmental fluctuations. They especially highlight the importance of considering both species interactions and environmental noise color when studying population dynamics in a fluctuating environment. A food web approach is necessary when analyzing species population dynamics and planning for conservation actions, especially when studying the effects of climate change on biodiversity.
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Sharp, C. "Human response to environmental noise and vibration from freight and passenger railway traffic." Thesis, University of Salford, 2014. http://usir.salford.ac.uk/33289/.
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There is currently a push to increase the proportion of freight traffic that is transported by rail, which is argued to be a safer, more sustainable and more climate friendly means of freight transportation when compared with road or air transportation. This will result in increased noise and vibration from freight railway traffic, the potential impacts of which are not well known. The aim of this research, therefore, is to further the understanding of the human response to freight railway noise and vibration. Data for this research comes from a field study comprising interviews with respondents and measurements of their vibration exposure. A logistic regression model was created and optimised, and is able to accurately classify 96% of these measured railway vibration signals as freight or passenger signals based on two signal properties that quantify the duration and low frequency content of each signal. Exposure-response relationships are then determined using ordinal probit modelling with fixed thresholds and cumulative ordinal logit models. The results indicate that people are able to distinguish between freight and passenger railway vibration, and that the annoyance response due to freight railway vibration is significantly higher than that due to passenger railway vibration, even for equal levels of exposure. To further investigate this disparity in response, a laboratory study was performed in which subjects were exposed to combined noise and vibration from freight and passenger railway traffic. Through the technique of multidimensional scaling, the subjective responses to these stimuli were analysed to investigate the specific attributes of the stimuli that may lead to the difference in human response. The results of this study suggest that the perception of combined railway noise and vibration takes into account not only the exposure magnitude of the noise and vibration stimuli, but also signal properties such as duration, spectral distribution and envelope modulation. These parameters, and in particular the duration parameter, appear to account for the difference in the human response to freight and passenger railway vibration.
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Nilsson, Oskar. "Quantifying Environmental Intolerance : Digital Reports From Daily Life." Thesis, Umeå universitet, Institutionen för psykologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-149052.
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Environmental intolerance (EI) is a condition characterized by low tolerance to environmental stimuli at levels that would not affect most people. EI is an ill-defined condition from which sufferers experience highly individual multisystem symptoms following exposure from specific environmental sources. Subgroups of EI are typically distinguished by the source that cause negative effects. In this study, intolerance attributed to noise and odors was investigated. Most research on EI is conducted using cross sectional approaches and among the instruments used to quantify EI is the Noise Sensitivity Scale (NSS-11) and the Chemical Sensitivity Scale for Sensory Hyperreactivity (CSS-SHR). To fully understand EI, more longitudinal research is needed. The aim of this study was to establish how a recently developed smartphone app, intended for longitudinal research, compares to the NSS-11 and CSS-SHR with regards to its ability to detect EI. 12 participants (mean age 29 years, SD=10.7 years) filled out the NSS-11/CSS-SHR following a period of two weeks using the app. It was hypothesized that individuals scoring high/low on the NSS-11/CSS-SHR would also express high/low levels of EI as measured by reports in the app on the variables discomfort rating, number of unique symptoms reported and number of reports. Although analyses revealed effects in the direction of the hypothesis for all variables, Independent samples t-test analyses yielded no significant associations. Either there are in fact no differences, but speculatively, the lack of significant associations can also be attributed any the following: (1) the groups were to similar (2) the sample was too small (3) the participants used avoidance as coping strategies.
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NEVIS, JAMES COFIE. "ANALYSIS OF AIRCRAFT NOISE ABATEMENT PROGRAMS: A CASE STUDY OF SELECTED GENERAL AVIATION/RELIEVER AIRPORTS." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100900239.
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Merchant, Nathan. "Measuring underwater noise exposure from shipping." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633173.
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Levels of underwater noise in the open ocean have been increasing since at least the 1960s due to growth in global shipping traffic and the speed and propulsion power of vessels. This rise in noise levels reduces the range over which vocal marine species can communicate, and can induce physiological stress and behavioural responses, which may ultimately have population-level consequences. Although long-term noise trends have been studied at some open-ocean sites, in shallower coastal regions the high spatiotemporal variability of noise levels presents a substantial methodological challenge, and trends in these areas are poorly understood. This thesis addresses this challenge by introducing new techniques which combine multiple data sources for ship noise assessment in coastal waters. These data include Automatic Identification System (AIS) ship-tracking data, shore-based time-lapse footage, meteorological data, and tidal data. Two studies are presented: in the first, AIS data and acoustic recordings from Falmouth Bay in the western English Channel are combined using an adaptive threshold, which separates ship passages from background noise in the acoustic data. These passages are then cross-referenced with AIS vessel tracks, and the noise exposure associated with shipping activity is then determined. The second study, at a site in the Moray Firth, Scotland, expanded the method to include shore-based time-lapse footage, which enables visual corroboration of vessel identifications and the production of videos integrating the various data sources. Two further studies examine and enhance basic analysis techniques for ambient noise monitoring. The first study examines averaging metrics and their applicability to the assessment of noise from shipping. Long-term data from the VENUS observatory are empirically assessed for different averaging times and in the presence of outliers. It is concluded that the mean sound pressure level averaged in linear space is most appropriate, in terms of both standardization and relevance to impacts on marine fauna. In the second study, a new technique for the statistical analysis of long-term passive acoustic datasets, termed spectral probability density (SPD), is introduced. It is shown that the SPD can reveal characteristics such as multimodality, outlier influence, and persistent self-noise, which are not apparent using conventional techniques. This helps to interpret long-term datasets, and can indicate whether an instrument’s dynamic range is appropriate to field conditions. Taken together, the contributions presented in this thesis help to establish a stronger methodological basis for the assessment of shipping noise. These methods can help to inform emerging policy initiatives, efforts to standardise underwater noise measurements, and investigation into the effects of shipping noise on marine life.
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Patel, Lopa. "Noise Pollution/Reduction Education for Frontline Staff in the Acute Care Setting." ScholarWorks, 2019. https://scholarworks.waldenu.edu/dissertations/6942.
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Noise levels in hospital settings have risen beyond the recommended range of 35-40 decibels, resulting in poor patient healing outcomes and other health conditions ranging from sleep deprivation, anxiety, agitation, delirium, depression, and high heart rate and blood pressure. These negative patient health experiences are evidenced by poor scores for the Hospital Consumer Assessment of Healthcare Providers and Systems, which are indicators of patients' perceptions of care. This project explored whether an educational activity for 48 direct care staff, who include registered nurses and nursing assistants, in a cardiac unit on the impact of noise pollution on patient healing would increase staff members' knowledge of interventions to reduce noise pollution. The information processing theory guided this project. Eighty-nine percent of the participants strongly agreed that the educational activity was relevant to their practice as health care providers on the cardiac monitored unit. All participants strongly agreed that they would be able to identify when the unit was noisy and when noise was impacting a patient both physiologically and psychologically. Participants indicated that they could implement the suggested behavioral modifications to promote a healing environment. Participants strongly agreed that the speaker was effective in communicating the importance of noise pollution and its impact on patient healing and ways in which to combat the problem (89%), and they were generally satisfied with the learning activity (91%). Reducing noise pollution might create a healing environment for cardiac patients, thus positively impacting patient satisfaction and well-being.
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de, Luis Jorge. "A Process for the Quantification of Aircraft Noise and Emissions Interdependencies." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24618.
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The main purpose of this dissertation is to develop a process to improve actual policy-making procedures in terms of aviation environmental effects. This research work expands current practices with physics based publicly available models. The process herein proposed provides information regarding the interdependencies between the environmental effects of aircraft. These interdependencies are also tied to the actual physical parameters of the aircraft and the engine, making it more intuitive for decision-makers to understand the impacts to the vehicle due to different policy scenarios. These scenarios involve the use of fleet analysis tools in which the existing aircraft are used to predict the environmental effects of imposing new stringency levels. The aircraft used are reduced to a series of coefficients that represent their performance, in terms of flight characteristics, fuel burn, noise, and emissions. These coefficients are then utilized to model flight operations and calculate what the environmental impacts of those aircraft are. If a particular aircraft does not meet the stringency to be analyzed, a technology response is applied to it, in order to meet that stringency. Depending on the level of reduction needed, this technology response can have an effect on the fuel burn characteristic of the aircraft. The proposed alternative is to create a fleet of replacement aircraft to the current fleet that does not meet stringency. These replacement aircraft represent the achievable physical limits for state of the art systems. In addition, the replacement aircraft show the linkage between environmental effects and fundamental aircraft and engine characteristics, something that has been neglected in previous policy making procedures. Another aspect that has been ignored is the creation of the coefficients used for the fleet analyses. In current literature, a defined process for the creation of those coefficients does not exist, but this research work develops a process to do so and demonstrates that the characteristics of the aircraft can be propagated to the coefficients and to the fleet analysis tools.
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Liu, Suyao. "SUSTAINABLE CITIES Environmental Development CASE STUDY IN CHINA----GUI YANG." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-14687.
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Pedersen, Eja. "Human response to wind turbine noise : perception, annoyance and moderating factors." Doctoral thesis, Göteborg : Occupational and Environmental Medicine, Department of Public Health and Community Medicine, Institute of Medicine, The Sahlgrenska Academy, Göteborg University, 2007. http://hdl.handle.net/2077/4431.
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Grubliauskas, Raimondas. "Research and Digital Modelling of Environmental Noise and its Reduction by applying Light Structures." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20090713_161749-77904.
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General characteristic of the dissertation
Problem of the work. With a rapid development of industrialisation and urbanisation, the environmental pollution has greatly increased. Upon automating the manufacturing industry and agriculture, with traffic flows in towns and residential areas increasing and household equipment becoming more modern, the number of acoustic discomfort zones is rapidly growing.
People are exposed to noise not only at workplaces abut also on the streets and at home. As maintained by doctors, noise reduces immunity of the organism and, as a source of chronic stress, has an adverse effect on the central nervous system and causes various health disorders. Even a relatively low noise of 60–70 dB causes a headache, dizziness, squeak in the ears, insomnia, and worsens memory, attention and orientation. A noisy environment reduces working efficiency, reaction speed, movement coordination and increases nervous strain and a risk of traumas.
The noise dispersed by stationary sources may be reduced by replacing components with less sounding ones, applying rubber, plastic or other materials on the surface of installations. If it is impossible to reduce noise in the place of its generation, hoods are fitted out, premises are insulated and noise suppressing systems are used (noise reducing barriers, volumetric noise absorbers, wall insulation with noise-proof materials).
The dispersion of traffic-generated noise is reduced by noise suppression walls, green... [to full text]Tiriamoji problema. Šiandieniniame gyvenime, mechanizavus pramonės ir žemės ūkio gamybą, didėjant transporto srautams miestuose ir gyvenvietėse, modernėjant buitinei technikai, sparčiai plečiasi padidinto triukšmo zonos. Medikai teigia, kad triukšmas mažina organizmo imuninį atsparumą ir įspėja, kad triukšmas, kaip lėtinis streso šaltinis, veikia centrinę nervų sistemą ir kelia įvairių sveikatos sutrikimų. Net palyginus nestiprus 60 – 70 dB triukšmas kelia galvos skausmus, nemigą, pablogėja atmintis, dėmesys, darbingumas. Stacionarių šaltinių skleidžiamas triukšmas sumažinamas keičiant detales keičiant, padengiant įrenginių paviršių guma, plastmase ir kt. Jeigu neįmanoma sumažinti triukšmo ten, kur jis kyla, įrengiami gaubtai, izoliuojamos patalpos, bei taikomos garsą slopinančios sistemos (triukšmą mažinantys barjerai, tūriniai garso sugėrikliai, sienos dengiamos garsą izoliuojančia medžiaga). Transporto keliamo triukšmą sklaidą mažina triukšmo slopinimo sienelės, želdiniai, pastatai. Taip pat veiksmingi būdai yra transporto greičio apribojimas, kelių dangos paviršiaus keitimas, eismo ribojimas ir reguliavimas. Inžineriniai sprendimai būna pigesni, jei įvertinami architektūrinio planavimo stadijoje. Nagrinėjant triukšmo mažinimo priemonių bei metodų įgyvendinimo galimybę, ypač svarbus skaitinis triukšmo sklaidos modeliavimas. Darbo aktualumas. Įvairūs technologiniai procesai kelia triukšmą. Leistini triukšmo lygiai viršijami ne tik darbo vietose ar įmonės teritorijose... [toliau žr. visą tekstą]
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Monazzam, Esmaeil Poor M. R. "Application of diffuser surfaces on single profile environmental noise barriers: evaluation, theory and optimization." Thesis, University of Salford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491800.
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Profile structures were previously introduced to improve the performance of noise barriers. Subsequent researches on reactive surfaces have shown that these surfaces improve the performance of the profile barriers at certain frequency ranges. This thesis details an investigation into prediction, measurement and the reduction mechanism of profile Schroeder diffuser barriers.
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Al-Noori, A. H. Y. "Robust speaker recognition in presence of non-trivial environmental noise (toward greater biometric security)." Thesis, University of Salford, 2017. http://usir.salford.ac.uk/44604/.
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The aim of this thesis is to investigate speaker recognition in the presence of environmental noise, and to develop a robust speaker recognition method. Recently, Speaker Recognition has been the object of considerable research due to its wide use in various areas. Despite major developments in this field, there are still many limitations and challenges. Environmental noises and their variations are high up in the list of challenges since it impossible to provide a noise free environment. A novel approach is proposed to address the issue of performance degradation in environmental noise. This approach is based on the estimation of signal-to-noise ratio (SNR) and detection of ambient noise from the recognition signal to re-train the reference model for the claimed speaker and to generate a new adapted noisy model to decrease the noise mismatch with recognition utterances. This approach is termed “Training on the fly” for robustness of speaker recognition under noisy environments. To detect the noise in the recognition signal two different techniques are proposed: the first technique including generating an emulated noise depending on estimated power spectrum of the original noise using 1/3 octave band filter bank and white noise signal. This emulated noise become close enough to original one that includes in the input signal (recognition signal). The second technique deals with extracting the noise from the input signal using one of speech enhancement algorithm with spectral subtraction to find the noise in the signal. Training on the fly approach (using both techniques) has been examined using two feature approaches and two different kinds of artificial clean and noisy speech databases collected in different environments. Furthermore, the speech samples were text independent. The training on the fly approach is a significant improvement in performance when compared with the performance of conventional speaker recognition (based on clean reference models). Moreover, the training on the fly based on noise extraction showed the best results for all types of noisy data.
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Russo, Domenico. "Innovative procedure for measurement uncertainty evaluation of environmental noise accounting for sound pressure variability." Doctoral thesis, Universita degli studi di Salerno, 2017. http://hdl.handle.net/10556/2574.
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2015 - 2016This study aims to demonstrate the importance of uncertainty evaluation in the measurement of environmental noise in the context of Italian legislation on noise pollution. Attention is focused on the variability of the measurand as a source of uncertainty and a procedure for the evaluation of uncertainty for environmental noise measurement is proposed. First drawing on several real noise datasets in order to determine suitable measurement time intervals for the estimation of the environmental noise, a data-driven sampling strategy is proposed, which takes into account the observed variability associated with measured sound pressure levels. Outliers are eliminated from the actual noise measurements using an outlier detection algorithm based on K-neighbors distance. As the third step, the contribution of measurand variability on measurement uncertainty is determined by using the normal bootstrap method. Experimental results exploring the adoption of the proposed method drawing upon real data from environmental noise using acquisition campaigns confirm the reliability of the proposal. It is shown to be very promising with regard to the prediction of expected values and uncertainty of traffic noise when a reduced dataset is considered. [edited by author]
Negli ultimi anni, studiosi ed esperti del settore hanno focalizzato la loro attenzione sulle possibili fonti di incertezza associabili a tale attività, cercando di pervenire a modelli che contemplassero tutte le variabili che concorrono alla determinazione dell’incertezza nella misura dei livelli di pressione acustica: l'incertezza dovuta alle caratteristiche della strumentazione di misura (fonometri o analizzatori multicanale), l'errore derivante dal posizionamento della strumentazione e quindi dei trasduttori microfonici, l'incertezza dovuta al calibratore, nonché l’incertezza da associare. Al fine, però, di fornire un’adeguata stima dell’indeterminazione associata alla misura del livello equivalente di rumore ambientale, risulta indispensabile considerare l’incertezza derivante dall’intrinseca variabilità del fenomeno in esame. Il tema risulta essere di particolare interesse scientifico e, negli ultimi anni, molti autori hanno proposto diverse metodologie di approccio al suddetto problema, in particolare alcuni hanno focalizzato l’attenzione sull’eliminazione dei segnali sonori non desiderati, altri sulla stima del tempo di misura e altri ancora direttamente sulla determinazione dell’incertezza. Alla luce di quanto esposto, ho pensato di integrare le diverse tecniche studiate in un’unica procedura, basata sul metodo bootstrap, tecnica statistica di ricampionamento con sostituzione del dataset iniziale, in quanto non ha limitazioni in termini di forma e di proprietà delle distribuzioni statistiche considerate ed è, pertanto, più adatta all’analisi del rumore ambientale, la cui popolazione non è strettamente gaussiana. Inizialmente, dal momento che l’affidabilità della stima degli indicatori di rumore ambientale dipende in modo significativo dalla variabilità temporale del rumore, e, quindi, risulta fondamentale scegliere in modo accurato il tempo di misura che tenga in considerazione la variabilità statistica del fenomeno acustico sotto osservazione, l’algoritmo individua in modo automatico un tempo minimo di acquisizione, corrispondente al numero minimo di livelli pressione sonora necessari a garantire la significatività statistica del set di dati di partenza. In una seconda fase sono individuati ed eliminati dal segnale acquisito eventuali valori anomali (outlier) ed, infine, è calcolata l’incertezza relativa al misurando applicando il metodo bootstrap. I risultati di tale metodo sono stati anche confrontati con la stima del valore atteso per il descrittore acustico a breve termine e della corrispondente incertezza applicando il metodo classico (GUM ISO). Poiché le grandezze calcolate con l’applicazione del metodo bootstrap si avvicinano molto a quelle determinate con il metodo classico nell’ipotesi di ridotto numero di campioni, tale procedura risulta altresì particolarmente adatta alla previsione dell'indicatore di rumore ambientale quando sono disponibili pochi dati di misura. [a cura dell'autore]
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Genari, Eliseu de Souza. "Acústica do ambiente externas às igrejas." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/16/16132/tde-03102015-095219/.
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Este projeto de pesquisa pretende contribuir para o tema da acústica do ambiente externo às igrejas, fornecendo um panorama em linhas gerais da natureza e magnitude das ocorrências sonoras externas às igrejas de uma área de amostragem constituída por 12 igrejas situadas em região urbana na cidade de São Paulo. A partir de dados coletados do entorno, das tipologias, dos resultados das medições sonoras e da aplicação de questionários, a pesquisa pretende compreender melhor as causas e os efeitos das fontes de ruído na vizinhança, bem como a de recomendar meios de prevenção dos problemas, tanto nos projetos de novas edificações como na escolha e adaptação de edificações existentes para a finalidade do culto religioso.This research project aims to contribute to the acoustic theme of the external environment to the churches, providing an overview in general terms the nature and magnitude of external sound events to the churches of a sampling area consists of 12 churches located in urban areas in the city of São Paulo. The data collected from the field survey, made available around the information and typology of the churches and the comparison of results of noise measurements,the research seeks to analyze the causes and effects of noise sources in the vicinity, as well as recommend means of preventing problems, both in the projects of new buildings in the choice and adaptation of existing buildings for the purpose of religious worship.
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Goldschagg, Paul. "Airport noise in South Africa : prediction models and their effect on land-use planning /." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/1292.
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