Environmental Noise

Invited Presentation to the Joint American and Japanese Acoustical Society Meeting in Hawaii in 1988.

Abstract

Sound intensity has received significant attention over the past five years in the fields of noise control and product noise analysis. Yet, at this date, it is an infrequently used technique in consulting acoustics in general. Standards have been slow in developing and thus have not increased its use, and the most fundamental reason for its use is still the utility of its results rather than any existing standard. The benefit of intensity measurement in architecture is principally in its ability to indicate source direction, and this benefit is particularly important in a number of fields now being studied. The first of these is the open plan office, and the current work in intensity is based on an interest in the performance of acoustical dividers and absorbers. The second field, for which intensity seems to be the only measurement technique that is easily used, is the analysis of compound element building facades. This analysis is aimed at developing field transmission loss values for facade elements, such as windows, doors, and wall sections.

Conforme a lo establecido en la legislación vigente, un mapa estratégico de ruido debe incluir un documento de texto con información sobre la metodología empleada y resultados obtenidos. En el caso de aglomeraciones urbanas, los ayuntamientos deben enviar al MAGRAMA un documento con la información recogida en el Anexo VI del RD1513/2005. El objeto de esta MEMORIA RESUMEN es dar respuesta a este requerimiento legal, en el contexto de la revisión del anterior MER de Granada de 2008. El alcance de este proyecto es el término municipal de Granada teniendo en cuenta su zonificación acústica, según se recoge en LORCA, plan de acción contra el ruido en la ciudad de Granada.

Environmental noise remains a complex and fragmented interplay between industrialization, population growth, technological developments, and the living environment. Next to the circulatory diseases and cancer, noise pollution has been cited as the third epidemic cause of psychological and physiological disorders internationally. A reliable and firm relationship between the cumulative health implications with the traffic annoyance and occupational noise has been established. This agenda has called for an integrated, coordinated, and participatory approach to the reliable protection of noise interference. Despite several fragmented policies, legislation and global efforts have been addressed; the noise pollution complaints have been traditionally neglected in developing countries, especially in Malaysia. This paper was undertaken to postulate an initial platform to address the dynamic pressures, gigantic challenges, and tremendous impacts of noise pollution scenario in Malaysia. The emphasis is speculated on the traffic interference and assessment of industrial and occupational noise. The fundamental importance of noise monitoring and modeling is proposed. Additionally, the confronting conservation program and control measure for noise pollution control are laconically elucidated.

The EU Directive 49 urges countries to prepare the strategic noise maps and the action plans for the agglomerations along major transportation routes and major industrial premises. Environmental engineers, town planners and architects are involved in preparation of action plans in which sound insulation of buildings are to be considered. This article describes a model to determine the required insulation performances for buildings’ external elements by using strategic noise maps. The model employs certain categorization for buildings in relation to indoor noise criteria and for insulation values to be assigned on building facades. A calculation procedure is integrated with the outputs of a noise mapping software to obtain the required noise reduction indexes in terms of both spectral values and the single-number ratings, i.e. “weighted- standardized level differences”. Calculated results are displayed graphically to be able to observe variation of insulation requirement throughout the surface exposed to noise source. Insulation map as a visual tool can facilitate building noise control and can be utilized in preparation of building specifications prior to construction phase and in developing the insulation codes by local administrations. Implementation of the model for two sample buildings located at different environments are explained in the article.► A methodology to determine required facade insulation based on strategic noise maps is explained. ► The approach enables transformation of facade noise levels into the insulation contours. ► The approach proposes a categorization scheme for applications. ► Insulation maps can be integrated with the strategic noise maps. ► Insulation maps facilitate acousticians’ task and architectural design of facades.

Documento FINAL del Grupo de Trabajo GT-15 de CONAMA10. Revisión del estado del arte en materia de Planes de Acción contra la contaminación acústica urbana, incluyendo un profundo análisis de propuestas y medidas y de la relación de este tipo de plan con otros planes de acción para la sostenibilidad urbana (Agenda 21 Local) GT-15 está compuesto por 40 miembros, todos autores de este documento. Jerónimo Vida es Coordinador nacional del GT.

A Relacre promoveu um Ensaio de Comparação Interlaboratorial (ECI) de Acústica -Critério de Incomodidade Sonora, que decorreu entre Novembro de 2007 e Janeiro de 2008. Este ECI teve por objectivo analisar o desempenho dos laboratórios participantes na aplicação do critério de incomodidade definido no Regulamento Geral do Ruído, de acordo com a NP 1730 e com a Circular clientes n.º 2/2007 IPAC. Para o efeito foi simulada uma situação de incomodidade produzida por uma fonte sonora, no interior de uma sala. Foi solicitado a cada laboratório participante que caracterizasse o nível sonoro produzido pela fonte, ruído ambiente, o respectivo nível de avaliação bem como o ruído residual. O presente artigo discute as dificuldades encontradas na preparação do ensaio, apresenta a metodologia utilizada na análise dos resultados, os resultados obtidos e as principais conclusões.

Documento FINAL del Grupo de Trabajo GT-ACU de CONAMA9. Elaboración de mapas estratégicos de ruido (MER) al amparo de la Directiva 2002/49/CE y normativa nacional derivada. Revisión del estado del arte, conocimiento técnico, problemas y retos para la elaboración de MER. GT-ACU está integrado por 41 personas. Jerónimo Vida es Coordinador nacional de GT-ACU.

Objectives. This study aimed to determine the effect of occupational training applied to workers working in noisy parts of a glass factory on the use of ear protectors. Methods. The study was a semi-experimental pre-test and post-test design. It was carried out with 45 workers determined by purposeful sampling and working in a glass production factory who accepted to participate in the study. The data were collected with an information form and noise-related symptom chart, hearing health information questionnaire and observation. In the analysis of the study data, the number/percentage, χ2 test, Cohen κ test and analysis of variance were used. Results. It was determined that workers pre training did not use ear protectors (100%) and there were some noise-related health complaints. There was an increase in using ear protectors (57.8%) and a decrease in their health complaints post training. It was also found that the workers’ pre-training hearing health information questionnaire mean score was 11.46 ± 3.20, and post training was 13.77 ± 3.42 in the first month and 15.77 ± 2.88 in the fourth month. Conclusions. Occupational training provided to the workers increased the workers’ awareness level and their rate of wearing ear protectors, and health problems caused by work-related noise started to recover.

Despite the significance of listening tests in identifying the human response to wind farm noise (WFN), little attention has been paid to methodological approaches relevant to WFN listening tests to date. Moreover, evidence on the potential adverse effects of WFN is still not well established. This paper thereby sheds light on the different quantification approaches of human response to WFN characteristics. There is also a discussion on the quality of current evidence regarding the effect of WFN on annoyance and sleep disruption. In the context of listening tests, separating WFN characteristics can be beneficial in many ways. Firstly, acceptable threshold levels for each component of WFN for daytime annoyance and night-time sleep disturbance can be quantified. Second, the most annoying characteristic of WFN can be identified. Third, the most annoying characteristics of WFN can be identified by combining two or more components of WFN. Finally, this helps determine the sufficiency of current penalties applied to WFN characteristics.

This paper discuss about environment noise, which happened in the middle of everyone's life, generally built by the industrial activity, trains, airplanes, and the highway traffic. But now, the highway traffic is the main of noise maker. That's happen because the noise from the highway make a comprehensive impact, instead of the others that just make a local impact, or just make an effect for some areas. Human, both of which have an activity outside or inside the building of some areas that near to the highway are potentially become a victim of noise effect. One of private school in Surabaya, Indonesia is so disturbed by the noise of the traffic flow. The school is directly facing the highway that makes a high level of noise. The noise that made by the flow of the traffic reaches 87 dBA, even though according to the standard noise level, the noise should be lower than 55 dBA for the school. Noise will decrease the capability of hearing and make a decrease in concentration of learning for the children. The value of NC (Noise Criteria) in the school parking area reaches 78 dBA, whereas in the area of the school, NC reaches 70 dBA. In this case, research focus in the room near the traffic flows. The students will be analyzed by doing the speech intelligibility test of phonetically balanced word. This test was conducted to determine the percentage of the students' clarity level of hearing.

Within the frame of European directive 2002/49 for Strategic Noise Mapping and the relevant environmental Noise Action Plans, which included preparation for the management of environmental noise and the rehabilitation of the sound environment, Greece had the opportunity to develop an innovative and comprehensive methodology to analyze the sound environments of several urban and semi-urban residential neighborhoods in the large and medium-size cities of the country e.g.,

Laboratory listening studies investigating human exposure-response relationships with amplitude-modulated wind turbine sound are re-examined using a common measure for modulation. Cross-study similarities and differences are observed and discussed within the context of establishing an evidence-based AM rating method for application in noise assessments.

This paper examines physical and perceptual properties of water sounds generated by small to medium sized water features that have applications for road traffic noise masking. A large variety of water sounds were produced in the laboratory by varying design parameters. Analysis showed that estimations can be made on how these parameters affect sound pressure levels, frequency content, and psychoacoustic properties. Comparisons with road traffic noise showed that there is a mismatch between the frequency responses of traffic noise and water sounds, with the exception of waterfalls with high flow rates, which can generate large low frequency levels comparable to traffic noise. Perceptual assessments were carried out in the context of peacefulness and relaxation, where both water sounds and noise from dense road traffic were audible. Results showed that water sounds should be similar or not less than 3 dB below the road traffic noise level (confirming previous research), and that stream sounds tend to be preferred to fountain sounds, which are in turn preferred to waterfall sounds. Analysis made on groups of sounds also indicated that low sharpness and large temporal variations were preferred on average, although no acoustical or psychoacousti-cal parameter correlated well with the individual sound preferences.

Man has been exposed to different types of sounds and noises since the dawn of civilization, but with the development of urban centers, the accumulation of different sound sources has degraded the environment and affected the quality of life. According to the World Health Organization (WHO), noise pollution occupies the second place in the ranking of environmental problems that most harm human health. Educational environments are not free from this negative impact. The activities developed in these places require a high degree of concentration to obtain satisfactory performance, however, several researches indicate how noise pollution has affected this performance. In this context, the present study had the objective of evaluating the environmental acoustics in the University City “Prof. José Aloísio de Campos ”from the Federal University of Sergipe (UFS), São Cristóvão - SE. The analysis of environmental acoustics occurred from an objective evaluation through measurements of sound pressure levels and acoustic maps obtained by computer simulation, in addition to subjective evaluations with the application of questionnaires on the perception and quality of the sound environment in a given internal area of the UFS Campus (São Cristóvão). The following steps were taken: 1. Physical characterization of the Campus (São Cristóvão) and selection of the analyzed areas and subareas; 2. Sound pressure level measurement; 3. Implementation and validation of the acoustic model (acoustic simulation software - iNoise 2020); 4. Generation of acoustic maps; 5. Application of questionnaires. 6. Tabulation and analysis of the results of objective and subjective evaluations. The measurements indicated that of the 30 measured points, 19 are above 50 dB (A), determined as the maximum limit in the daytime for school environments, NBR 10.151 (ABNT, 2019). Through the acoustic map, it was identified that the noisiest places on the campus are close to the surrounding arterial roads, with intense vehicle traffic (main source of linear noise); among some didactics, where air conditioning compressors are installed; and in places where people chat. Despite the interference of these point sources, the campus core is the region analyzed most quietly, corresponding to Democracy Square, the main place of sociability, in which the sound most perceived by 47% of the interviewees is that of nature. Of the 148 questionnaires applied, 45% of users stated that they have already felt harmful effects associated with noise within UFS. Therefore, this study highlights the importance and the need for noise control in sensitive areas, such as a university, and the acoustic map can contribute to the planning of future campus facilities.

Social surveys have established dose-response relationships between aircraft noise and annoyance, with a number of psychological symptoms being positively related to annoyance. Evidence that exposure to aircraft noise is associated with higher psychiatric hospital admission rates is mixed. Some evidence exists of an association between aircraft noise exposure and use of psychotropic medications. People with a pre-existing psychological or psychiatric condition may be more susceptible to the effects of exposure to aircraft noise. Aircraft noise can produce effects on electroencephalogram sleep patterns and cause wakefulness and difficulty in sleeping. Attendances at general practitioners, self-reported health problems and use of medications, have been associated with exposure to aircraft noise, but some findings are inconsistent.

The ISO 1996-2:2008 standard, currently under review and dealing with the description and assessment of environmental noise, suggests applying corrections to the readings in situations where the microphone is mounted directly on a facade or on some of its elements. To obtain the value equivalent to the sound pressure level in free field, the correction corresponds to subtracting 3 dB or 6 dB from the measured value, for the situations where the microphone is located at a distance of 2 m from the facade or directly placed on it, respectively.

Background: Noise annoyance is considered to be the most widespread and recognized health effect of environmental noise. Previous research is mostly based on the static study of residential environmental noise, but few studies have focused on the effects of noise exposure in different activity contexts on real-time annoyance. The two deficiency are that they neglect the influence of activity context besides residence and fail to reflect the difference of timescale effect of noise influence. Methods: Using portable noise and air sensors, GPS-equipped mobile phones, questionnaire survey, and geographic ecological momentary assessment (GEMA), this paper measured the environmental noise and real-time noise annoyance of participants at different activity places. Hierarchical logistic regression models were used to examine the effects of environmental noise on people's real-time annoyance. The paper further considered the influence of the geographic context of the activity places and daily acoustic environment on participants' real-time annoyance. Further, a nonlinear regression model was constructed using Random Forest to further examine the nonlinear relationship between environmental noise and real-time annoyance. Results: The results showed that: (1) the average cumulative equivalent sound level during was 55 dB (A) when the participants responded to the EMA surveys; (2) Only the temperature of activity places had an influence on momentary annoyance and the higher the temperature, the more likely participants were annoyed; (3) Participants with higher perception of noise pollution in residential communities were more likely to be annoyed. However, participants with higher daily exposure to noise were less likely to feel annoyed; (4) The threshold value of the effect of noise on real-time annoyance was 58 dB (A) to 78 dB (A). Conclusions: These findings can guide the development of urban planning and environmental noise standards and also provide a reference for noise barrier requirements for different activity places.

This empirical study examines the contributory factors of the environmental noise generated by traffic. The degree of variance in Noise descriptors and Indicators is studied and analyzed for both at and above grade links of flyovers to establish a correlation with its causative factors. Noise measurements were taken on weekdays three times a day during peak hours and carried out at 24 locations both at grade and above grade. The study reveals ambient noise levels, other noise descriptors, and noise indicators were above permissible levels for the land use. The study also revealed that major contributor to noise emission from vehicles traveling on access controlled links was higher, followed by volume and density. The study also revealed that noise levels were significantly lower on at grade locations than those above grade locations of the flyover with a standard deviation of 3-4 dB(A). The land use zones abutting the flyover areas studied were residential, educational and hospital zones which further indicate that high speed volumes of traffic through sensitive neighbourhoods should be avoided. The study results are significant to understand and identify factors contributing to noise intense environments which are a potential hazard and detrimental to the health and well-being of users. The study is also an aid to stakeholders for planning, drafting policies, conducting an ex-ante assessment as well as decision making in mitigation strategies or projects.

Abstract Transverse rumble strips (TRS) are widely used by local authorities to reduce vehicle speed and to alert the driver of road conditions ahead. This study investigated the application and effects of installation of TRS on the roadway to the traffic noise climate condition. The evaluations were carried out through changes in noise levels and changes in traffic noise index (TNI) which indicate the dissatisfaction. The samplings were performed at a road installed with two types of TRS which has most noise complaints, located at a highway that passes through a rural area of South Malaysia. Results show that TRS increase the sound level indices L Aeq , L 10 , L 90 significantly and also increase the TNI values. All TNI values exceed the value intended for planning purposes. Therefore, engineers should compromise the environmental effects and the role of TRS as a tool in safety aspect.

This paper presents a comparison of two noise assessments in the Gdansk agglomeration in Poland. One is based on the noise map produced by computational method for the city in 2007, the second one is based on real data from continuous measurements acquired by a noise monitoring network operating in the city since 2008. Differences are shown and analyzed. Additionally, seasonal and weekday influence on noise indicators (L DEN , L D , L E and L N ) is analyzed and discussed in this paper.

Knowledge on primary processing of sound by the human auditory system has tremendously increased. This paper exploits the opportunities this creates for assessing the impact of (unwanted) environmental noise on quality of life of people. In particular the effect of auditory attention in a multisource context is focused on. The typical application envisaged here is characterized by very long term exposure (days) and multiple listeners (thousands) that need to be assessed. Therefore, the proposed model introduces many simplifications. The results obtained show that the approach is nevertheless capable of generating insight in the emergence of annoyance and the appraisal of open area soundscapes.

This paper examines the audio-visual interaction and perception of water features used over road traffic noise, including their semantic aural properties, as well as their categorization and evocation properties. The research focused on a wide range of small to medium sized water features that can be used in gardens and parks to promote peacefulness and relaxation. Paired comparisons highlighted the interdependence between uni-modal (audio-only or visual-only) and bi-modal (audiovisual) perception, indicating that equal attention should be given to the design of both stimuli. In general, natural looking features tended to increase preference scores (compared to audio-only paired comparison scores), while manmade looking features decreased them. Semantic descriptors showed significant correlations with preferences and were found to be more reliable design criteria than physical parameters. A principal component analysis identified three components within the nine semantic attributes tested: " emotional assessment, " " sound quality, " and " envelopment and temporal variation. " The first two showed significant correlations with audio-only preferences, " emotional assessment " being the most important predictor of preferences, and its attributes naturalness , relaxation, and freshness also being significantly correlated with preferences. Categorization results indicated that natural stream sounds are easily identifiable (unlike waterfalls and fountains), while evocation results showed no unique relationship with preferences.

Background: Noise mapping being an established practice in Europe is hardly practiced for noise management in India although it is mandatory in Indian mines as per guidelines of the Directorate General of Mines Safety (DGMS). As a pilot study, noise mapping was conducted in an opencast mine with three different models; one based on the baseline operating conditions in two shifts (Situation A), and two other virtual situations where either production targets were enhanced by extending working hours to three shifts (Situation B) or only by increased mechanization and not changing the duration of work (Situation C). Methods: Noise sources were categorized as point, line, area, and moving sources. Considering measured power of the sources, specific meteorological and geographical parameters, noise maps were generated using Predictor LimA software. Results: In all three situations, L den values were 95 dB(A) and 70–80 dB(A) near drill machine and haul roads, respectively. Noise contours were wider in Situation C due to increase in frequency of dumpers. L den values near Shovel 1 and Shovel 2 under Situation B increased by 5 dB and 3 dB, respectively due to expansion of working hours. In Situation C, noise levels were >82 dB(A) around shovels. Noise levels on both sides of conveyor belts were in the range of 80–85 dB(A) in Situations A and C whereas it was 85–90 dB(A) in Situation B. Near crusher plants, it ranged from 80 to 90 dB(A) in Situations A and C and between 85 and 95 dB(A) in Situation B. In all situations, noise levels near residential areas exceeded the Central Pollution Control Board (CPCB) limits, i.e., 55 dB(A). Conclusions: For all situations, predicted noise levels exceeded CPCB limits within the mine and nearby residential area. Residential areas near the crusher plants are vulnerable to increased noise propagation. It is recommended to put an acoustic barrier near the crusher plant to attenuate the noise propagation.

We describe a discrete-time, stochastic population model with density dependence, environmental-type process noise, and lognormal observation or sampling error. The model, a stochastic version of the Gompertz model, can be transformed into a linear Gaussian state-space model (Kalman filter) for convenient fitting to time series data. The model has a multivariate normal likelihood function and is simple enough for a variety of uses ranging from theoretical study of parameter estimation issues to routine data analyses in population monitoring. A special case of the model is the discrete-time, stochastic exponential growth model (density independence) with environmental-type process error and lognormal observation error.

Determining how thermal variability will affect the structure, stability, and function of ecological communities is becoming increasingly important as global warming is predicted to affect not only average temperatures but also increase the frequency of long runs of high temperatures. Latitudinal differences in the responses of ecological communities to changes in their thermal regimes have also been predicted based on adaptations over evolutionary time to different thermal environments. We conducted an experiment to determine whether variability in temperature leads to consistent changes in community structure, temporal dynamics, and ecosystem functioning in laboratory analogues of natural freshwater supralittoral rock pool communities inhabited by meiofauna and zooplankton collected from sub-Arctic, temperate, and tropical regions. Thermal variability of +4°C around mean temperature led to increased extinction frequency, decreases in consumer abundance, increases in temporal variability of consumer abundance, and shifts from predominately negative interactions observed under constant temperature to positive interactions in the temperate and tropical communities but not in the sub-Arctic communities. That sub-Arctic zooplankton communities may be more robust to thermal variability than temperate or tropical communities' supports recent studies on macrophysiological adaptations of species along latitudinal gradients and suggests that increasing thermal variability may have the greatest effects on community structure and function in tropical and temperate regions.

The ''Galileo Galilei'' airport is a civil and military airport quite close to central Pisa. Although the airport brings benefits in terms of tourism and different types of income, the air traffic growth exacerbates the exposition to aircraft noise. This could significantly affect public health. To this day, a small number of studies takes into account the standard indicators of Europe by considering noise emission data for military aircrafts. We estimated the noise impact produced by the airport and we evaluated the related exposed population by using the Integrated Noise Model (INM). The noise power levels of both commercial and military flights have been considered as an input to the model. Predicted levels were validated by means of a noise-monitoring network. A new tracking system (AirNav Radar) that captures Automatic Identification System (AIS) signals emitted by each aircraft has been used to emulate takeoff and landing procedures. This improves the accuracy of the input to the model. We simulated noise maps for present and future scenarios, including those following the application of noise reduction measures. For each situation, we also estimated the exposure of the population and the percentages of highly annoyed and highly sleep disturbed people. We show the utility of AIS data and their specific elaboration to draw up noise abatement measures in order to reduce the noise impact on population and allow the airport development.

This study assessed the environmental noise of select industries in Chittagong city and tried to relate the findings with occupational health to evaluate the vulnerability of workers toward possible health injuries. Sound levels were measured based on industry types and zones within industries. Eight different industries of the Nasirabad area were selected, divided into three zones, and categorized as steel, garments, and aluminium industries. The mean maximum and minimum sound levels ranged between 77.26 to 96.53 and 67.71 to 86.62 dBA, respectively. Sound levels also varied significantly (p < 0.05) within the same and between the different zones. From median observation, 25 th and 75 th percentiles maximum and minimum sound levels again showed a significant (p = 0.00) variation for different types of industries. The overall analysis of this study could be regarded as arbitrary baseline data for further studies or concerned stakeholders in Chittagong city.

During the past four decades, extensive research has been carried out on different noise barrier shapes using analytical and physical modelling as well as full scale testing. This paper reviews traffic noise barrier research and its findings to date. It provides a catalogue of noise barrier profiles; identifying the relative acoustic benefits of each and the physical principles on which they operate. The likely effects of ground and atmospheric conditions on their absolute acoustic performance are described. The types of barriers which are commonly used in practice and those deserving further attention are highlighted. Based on the findings of previous work, recommendations are made on possible areas of further research.

The city of Granada is experimenting a big urban transformation, attending national and international commitments on clean air, energy efficiency and savings linked to greenhouse gases reduction strategies and sustainable development action plans. This situation constitutes a good scenario for new noise control approaches that take into account the sound variable and citizens empowering in urban design, such as the soundscape assessment of urban territory. In this way, soundscape tools have been used in Granada as a complementary method for environmental noise characterisation where traditional noise control techniques are difficult to be carried out or give limited results. After 2016 strategic noise map and in the preparation of the new noise action plan, the city came across a great acoustic challenge in a new area located outskirts characterised by growing urbanisation, still under development, the greatest legal protection because of sensitive teaching and hospital buildings and the greatest noise exposure from nearby ringway supporting heavy traffic flow. As quiet urban areas are not characterised by the absence of noise but for the presence of the right noise, this research intended to provide the local administration with results and proposals to transform this conflict area in a pleasant or quiet urban place. Main results came from important and significative differences in morning and evening characterisation, as great differences appear in soundscape assessment over the day and along the soundwalk path, indicating the importance of time and local issues to adequately characterised citizens perception to be considered by administration in the development of strategies and effective noise control actions.

Recent work in the field of wireless sensing networks shows that cheap sensing platforms like wireless sensor nodes or mobile phones can be used, or "misued", for monitoring environmental pollution levels. In particular, several authors dedicated their attention to the problem of the assessment of environmental noise levels in urban environments, a complex and expensive task that public administrations and often also private entities are willing or forced to take over. In this paper, we review the approaches that have been presented within the wireless sensing research community and report on our own experiences in assessing noise pollution levels using both sensor nodes and mobile phones. Drawing form other authors' and our own work, we outline common pitfalls and open issues in the implementation of wireless noise monitoring systems and provide practical considerations that can speed up and advance the development of such systems.

We introduce a non-negative matrix factorization technique which learns speech features with temporal extent in the presence of non-stationary noise. Our proposed technique, namely Sparse convolutive robust non-negative matrix factorization, is robust in the presence of noise due to our explicit treatment of noise as an interfering source in the factorization. We derive multiplicative update rules using the alpha divergence objective. We show that our proposed method yields superior performance to sparse convolutive non-negative matrix factorization in a feature learning task on noisy data and comparable results to dedicated speech enhancement techniques.

Government authorities are faced with a number of challenges when attempting to regulate noise from outdoor concerts. A key difficulty is the ability of an authority to meaningfully influence the behaviour of a concert operator during the concert itself. In many jurisdictions, penalties for environmental noise nuisance are an insufficient deterrent-resulting in permit conditions and noise limits being routinely exceeded or ignored. Authorities can also face a regulatory burden where noise conditions are technically difficult to measure, difficult to determine compliance, and require specialised equipment and staff to be available outside standard business hours. Noise regulations need to be carefully determined with the aim of motivating good noise self-regulation without being prohibitively punitive or impractical. Noise limits need to consider the realistic sound levels that are needed to hold a successful concert, while still preventing unreasonable behaviour. This strategy has been implemented by setting noise measurement locations at the sound mixing desk. Mixing desk staff can then monitor their own levels with immediate feedback and corrections where required. Self-monitoring provides industry with the ability to clearly demonstrate responsible behaviour to authorities and the community and it provides certainty and security for future use of the venue.

Evaluation and analysis of noise pollution levels have been carried out to determine the level of noise and its sources in Ilorin metropolis. Noise measurements have been done in the morning, at noon, in the evening, and at night to determine noise pollution all over the city. The selected areas of study are commercial centers, road junctions/busy roads, passenger loading parks, and high-density and low-density residential areas. The road junctions had the highest noise pollution levels, followed by commercial centers. The results of this study show that the noise levels in Ilorin metropolis exceeded allowed values at 30 of 42 measurements points. There is a significant difference (P < 0.05) in the noise pollution levels and traffic noise index in all the locations. From the measured noise values, a map of noise pollution was developed for Ilorin. Many solutions proposed for noise abatement in the city are set out.