1,720,958 research outputs found
Effects of reverberation and amplification on sound localisation
No full textCommunication often takes place in reverberant spaces making it harder for listeners to understand speech. In such difficult environments, listeners would benefit from being able to locate the sound source. In noisy or reverberant environments hearing-aid wearers often complain that their aids do not sufficiently help to understand speech or to localise a sound source. Simple amplification does not fully resolve the problem and sometimes makes it worse. Recent improvements in hearing aids, such as compression and filtering, can significantly alter the Interaural Time Difference (ITD) and the Inter-aural Level Difference (ILD) cues. Digital signal processing also tends to restrict the availability of fine structure cues, thereby forcing the listener to rely on envelope and level cues. The effect of digital signal processing on localisation, as felt by hearing aid wearers in different listening environments, is not well investigated. In this thesis, we aimed to investigate the effect of reverberation on localisation performance of normal hearing and hearing impaired listeners, and to determine the effects that hearing aids have on localisation cues. Three sets of experiments were conducted: in the first set (n=22 normal hearing listeners) results showed that the participants’ sound localisation ability in simulated reverberant environments is not significantly different from performance in a real reverberation chamber. In the second set of four experiments (n=16 normal hearing listeners), sound localisation ability was tested by introducing simulated reverberation and varying signal onset/offset times of different stimuli – i.e. speech, high-pass speech, low-pass speech, pink noise, 4 kHz pure tone, and 500 Hz pure tone. In the third set of experiments (n=28 bilateral Siemens Prisma 2 Pro hearing aid users) we investigated aided and unaided localisation ability of hearing impaired listeners in anechoic and simulated reverberant environments. Participants were seated in the middle of 21 loudspeakers that were arranged in a frontal horizontal arc (180°) in an anechoic chamber. Simulated reverberation was presented from four corner-speakers. We also performed physical measurements of ITDs and ILDs using a KEMAR simulator. Normal hearing listeners were not significantly affected in their ability to localise speech and pink noise stimuli in reverberation, however reverberation did have a significant effect on localising a 500 Hz pure tone. Hearing impaired listeners performed consistently worse in all simulated reverberant conditions. However, performance for speech stimuli was only significantly worse in the aided conditions. Unaided hearing impaired listeners showed decreased performance in simulated reverberation, specifically, when sounds came from lateral directions. Moreover, low-pass pink noise was most affected by simulated reverberation both in aided and unaided conditions, indicating that reverberation mainly affects ITD cues. Hearing impaired listeners performed significantly worse in all conditions when using their hearing aids. Physical measurements and psychoacoustic experiments consistently indicated that amplification mainly affected the ILD cues. We concluded that reverberation destroys the fine structure ITD cues in sound signals to some extent, thereby reducing localisation performance of hearing impaired listeners for low frequency stimuli. Furthermore we found that hearing aid compression affects ILD cues, which impairs the ability of hearing impaired listener to localise a sound source. Aided sound localisation could be improved for bilateral hearing aid users, if the aids would synchronize compression between both sides
Comparison Study of Water Quality Produced from a Conventional Water Treatment Plant and a Number of Compact Units
No full textWater is very plentiful through the planet in general. Nevertheless, clean drinking water is not always accessible in the proper time or place for sufficient public or ecological use. The water significance is emphasized by the fact that in the past, great cultures have arisen near and along water bodies. Water quality of some purification complexes (compact units) in the Babylon Province (13 compact unit) as compared with Al-Hillah Al Mouahad Project (water treatment plant) was assessed by the Water Quality Index (WQI) methodology. WQI offers a particular number that states the overall water quality at a definite place and period based on many parameters concerning the quality of water. The water produced from the compact units was classified as "good water" according to the WQI classification with the values ranging from 85.4 in Bermana unit to 99.17 in Al-Muamera compact unit. Moreover, the research results showed that the water purification complexes work with efficiency, very close to the performance of large water purification projects and stations, and this means that it is possible to rely on them to obtain good drinking water quality, especially in small or remote areas
Analysing the context of nonverbal behavioural cues in multiple social settings
No full textAbstract not currently available
Using the Wastewater Quality Index to Assess the Compliance of Treated Wastewater with Iraqi Standards
No full textThe acute scarcity of water and the increasing demand for it for various purposes have become a major problem facing most countries suffering from water scarcity and limited water resources. Therefore, monitoring the quality of wastewater discharged into water sources has become an urgent necessity to reduce the pollution of these limited resources. This study used the Wastewater Quality Index (WWQI) method to assess the quality of treated wastewater discharged from the Biological Al Thaghr Treatment Plant into the Tigris River in Basra Governorate, by evaluating the plant\u27s performance over a full year, 2023. The WQI results showed that only 36.36% of the studied period was the discharged water of good quality. The concentrations of a range of physical and chemical variables in the discharged wastewater to the water body were also compared with the Iraqi standards for this type of water. The results showed that the concentrations of most variables were within the permissible limits, except for a few that exceeded these limits, namely EC, TDS, and CL.اصبحت الندرة الحادة للمياه والطلب المتزايد عليها لاغراض مختلفة مشكلة رئيسية تواجه معظم البلدان التي تعاني من ندرة المياه ومحدودية الموارد المائية, لذلك اصبحت مراقبة جودة مياه الصرف الصحي المصرفة في مصادر المياه ضرورة ملحة للحد من تلوث هذه الموارد المحدودة. استخدمت هذه الدراسة طريقة مؤشر جودة مياه الصرف الصحي (WWQI) لتقييم جودة مياه الصرف الصحي المعالجة المصرفة من محطة معالجة الثغر البايلوجية الى نهر دجلة في محافظة البصرة، من خلال تقييم اداء المحطة على مدار عام كامل، 2023، اظهرت نتائج مؤشر جودة مياه الصرف الصحي ان 36.36% من فترة الدراسة كانت فيها مياه تصريف ذات نوعية جيدة. كما تمت مقارنة تركيزات مجموعة من المتغيرات الفيزيائية والكيميائية في مياه الصرف الصحي المصرفة الى المسطح المائي بالمعايير العراقية لهذا النوع من المياه. اظهرت النتائج ان تركيزات معظم المتغيرات كانت ضمن الحدود المسموح بها، بأستثناء عدد قليل منها تجاوز الحدود وهي EC, TDS, CL.
Wastewater Pollutants Modeling Using Artificial Neural Networks
No full textIn this study, the execution and assessment of the ANN approach towards the declaration of the pollution was used. The ANN-based models for prediction of Chemical and Biological Oxygen demands, (COD & BOD5) and Total Suspended Solids (TSS) concentrations in the effluent were formed using a three-layered feed forward back propagation algorithm ANN towards assessing the performance of a wastewater treatment plant (WWTP). Two types of configurations were used, MISO and MIMO. The study showed the superiority of MIMO according to the results of R and MSE, which were used as evaluation functions for the predicted models. The results also showed that the model built to predict the values of BOD5 concentrations demonstrate the best performance among the rest of the models by achieving the value of correlation coefficient up to 0.99. Among the input combinations tested in the study, the models the inputs of which did not contain BOD5 had the best performance, which demonstrates that the BOD5 has the largest influence on the values of R in the COD prediction models as well as other predicted models than TSS and other parameters; consequently, the performance of the WWTP was greatly affected. This study demonstrated the value of using artificial networks to represent the complex and non-linear relationship between raw influent and treated effluent water quality measurements
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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