Browsing by Subject "Auditory perception"
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Item Open Access An approach based on sound classification to predict soundscape perception through machine learning(Bilkent University, 2021-06) Acun, VolkanA growing amount of literature and a series of ISO standards focus on concept, data collection, and data analysis methods of soundscapes. Yet, this field of research still lacks predictive models. We hypothesize that machine learning methods can be used to develop a predictive model by identifying the audio content of soundscapes and correlating it with individuals’ perceived affective response to the soundscapes. Therefore, this research aims to identify machine learning-based sound classification methods for analyzing the audio content of soundscapes and using its output in a second model for evaluating the association between the audio content and perception of the soundscape. We focused on museum soundscapes to conduct our research. The methodology of this thesis is divided into two parts. For the first part, we used Convolutional Neural Networks for classifying the audio content of the soundscape. Due to their limitations, we used a different approach rather than the typical environmental sound classification methods. We used musical instruments for the training dataset and optimized the neural network for this type of task. The convolutional neural network classified the audio content of the soundscapes based on their similarities to the musical instruments of the dataset. We conducted an online soundscape perception survey to measure participants' affective responses to different museum soundscapes for the second part. To predict individuals’ perception of soundscapes, we developed a feedforward neural network model. This model used the audio content output from the sound classification model and the soundscape survey data to predict the perceived affective quality of soundscapes. We concluded the thesis by conducting statistical analyses to explore the association between the variable used in the predictive model.Item Open Access A comparative study on indoor soundscape in museum environments(Bilkent University, 2019-07) Orhan, CemreThe aim of this study is to understand how visitors perceive and compare the soundscapes of different museum environments. To reach this goal, physical parameters as acoustic measurements, and perceptual data as questionnaires and interviews were explored in Rahmi M. Koç Museum, and Erimtan Archaeology and Arts Museum. Both museums are located near the main gate of Ankara Castle, which is one of the most historic and cultural part of the city. To find out the acoustical parameters of the case study settings, Equivalent Continuous A-weighted Sound Level (LAeq) was measured in-situ with Bruel & Kjaer 2230 sound level meter, and Speech Transmission Index (STI) and Reverberation Time (T30) were measured with the Odeon Room Acoustics Software 13.01. For the perceptual data, the questionnaires were analyzed by using SPSS program. Interviews were analyzed with the Grounded Theory (GT) method to explore the visitors’ perception towards the indoor soundscapes of museum environments. After analyzing the data of interviews, the conceptual framework was created. This process was completed with the ATLAS.ti Software. Results showed that the soundscapes of the indoor environment cannot be explored only with physical parameters. Results showed that visitors’ perception of soundscape changes according to the theme of the museums, and visitors’ preference of sound environment changes according to the building types.Item Open Access A comparative study on indoor soundscape assessment via a mixed method: A case of the high school environment(Elsevier, 2022-02-28) Çankaya Topak, Sıla; Yılmazer, SemihaEnvironments for learning-teaching activities require optimum acoustical conditions since students learning attitudes are directly related to verbal speaking. However, optimum acoustical conditions are not enough to provide acoustic comfort to students. To explore the acoustic requirements of educational spaces, there is a need to understand the role of sound and in which factors auditory perception of stu- dents changes. This study explores the relationship between auditory perception and the built environ- ment in a high school. It aims to provide design guidelines for educational facilities using the systematic categorization that defines the comparison between classroom and computer laboratory spaces in _Ihsan Dog ̆ramacı Foundation Bilkent High School. To understand the existing acoustic conditions in a selected educational facility, Equivalent Continuous A-Weighted Sound Level (LAeq), Reverberation Time (T30), and Speech Transmission Index (STI) were measured. This mixed method study includes quantitative and qualitative research methods. Data was collected through multiple instruments, including a ques- tionnaire survey (n = 117) and semi-structured interviews (n = 50). The data analyses were conducted using SPSS v.20 statistical software and applying the method of Grounded Theory (GT). The results show that the auditory perception of students does not only depend on sound levels since the responses towards sound sources and sound levels changed depending on the context of the space (such as the lec- ture content or the students’ task). The conceptual framework presented the relations between the built environment, acoustic environment, and auditory perception of students. The results of this research were interpreted for possible improvement directions, providing a guideline for designers to shape the auditory quality of future educational spacesItem Open Access Examining the effects of audiovisual associations on motion perception through task-based fMRI(Yerkure Tanitim ve Yayincilik Hizmetleri A.S., 2018) Kafalıgönül, HulusiExamining the effects of audiovisual associations on motion perception through task-based fMRI Objective: Previous studies showed that associative learning can lead to drastic changes in perceptual experience and unexpected levels of sensory plasticity in the adult brain. However, how associative learning is involved in shaping perception and the underlying neural mechanisms are quite poorly understood. In the current study, by taking advantage of well-studied visual motion-processing hierarchy, the roles of different brain areas in audiovisual association-induced changes in motion perception are investigated. Method: Using a previously developed audiovisual associative paradigm, behavioral and Blood Oxygen Level Dependent (BOLD) data were collected from adult human participants (n=13) before and after the association phase. Behavioral data were collected through reports on visual motion direction. Functional magnetic resonance imaging (fMRI) was based on block design and the functional data were analyzed according to a general linear model. Results: Audiovisual associations, acquired within a short time and without any feedback, significantly affected the perception of motion direction. This effect was much more salient when the physical direction of visual motion was ambiguous. Moreover, fMRI findings pointed out that the BOLD activities across different cortical regions changed after the associative phase. Conclusion: Taken together, these findings indicate that low-level sensory, multisensory and high-level cognitive areas play a role in the effects of audiovisual associations on motion perception. In general, this suggests that our prior experiences acquired through associations may affect perceptual processing at different hierarchical levels and over different cortical areas.Item Open Access Harmony of context and the built environment: soundscapes in museum environments via GT(Elsevier Ltd, 2021-02) Orhan, Cemre; Yılmazer, SemihaThis paper presents an approach to analyze visitors' expectations and perceptions of museums' built and auditory environments. It aims to explore visitors' perception of acoustic and built environments in museums, generate a systematic categorization, and create a conceptual framework using the Grounded Theory (GT) approach. We measured the Equivalent Continuous A-weighted Sound Level (LAeq) and, following the ISO/TS 12913-2/3, conducted semi-structured interviews and questionnaire surveys were conducted to discover the sound environments and capture the subjective responses of visitors in two museums: the Rahmi M. Koç Museum (RMK) and the Erimtan Archaeology and Arts Museum (EAA) (both located in the most historical part of Ankara, Turkey). Although the selected museums offer two different experiences based on themes, exhibitions, and interior designs, we examined whether the museums’ soundscapes, connected contextually to the historical environment, could be perceived different from one another. Results show that Museum RMK, which has historical exhibitions and an historical building type, is more appealing to people's preferences and expectations than Museum EAA, which has historical exhibitions and a modern building type. The findings of the study reveal that peoples' perceptions are mostly dependent on the context in which sound is heard, rather than on sound levels in museums. In some areas, where sound was used as a design element, visitors had a better museum experience because they were able to interact with the exhibited objects on exhibit and feel as if they were living in a specific period.Item Open Access Investigating the effect of indoor soundscaping towards employees’ mood and perception in open plan offices(Bilkent University, 2015-08) Acun, VolkanOver the past decade, soundscape studies have proposed ways to differentiate sonic environments and showed that it is not always the sound levels that matters. Meanings associated with sound sources, how they are perceived by the listener and the physical settings are equally important. On the other hand, very few studies are conducted to examine whether these principles of soundscape can be applied to indoor spaces. Aim of this research is to identify sound sources within an open office space, understand how employees’ perceive these sound sources, explore its impact on their mood and task performance. In order to achieve this goal, measurements and interviews are conducted at two different open planed offices. A user focused, subjective, approach of Grounded Theory, is used to capture the lived experience of an open plan office space and examine the effects of indoor soundscape quality towards employees’ perception of their work environment. PANAS (Positive and Negative Affect Schedule) test is conducted to explore employees’ mood. In order to understand the acoustical conditions of case study settings, in-situ measurements of sound levels (Leq), ODEON simulation of Speech Transmission Index (STI) and Reverberation Time (T 30) is used. Semi-structured interviews, as part of Grounded Theory, and PANAS test are conducted with 47 employees. Their responses are used to generate a conceptual framework which conceptualizes employees’ subjective response to the soundscape of their work environment. Generated conceptual framework showed patterns between employees' perception of sound sources, sound preference and type of work they are performing as well as the association between positive affect (PA), negative affect (NA) and soundscape.Item Open Access Relationships between measured levels and subjective ratings: A case study of the food-court area in CEPA shopping center, Ankara(SAGE, 2012-03-01) Dökmeci, P. N.; Yilmazer, S.Physical comfort requirements of users; such as, thermal, visual, and acoustic comfort, should be considered and studied in detail when planning and designing public spaces. However, there is not enough research on the relations between the acoustical parameters, and the acoustic comfort level of users in enclosed non-acoustic public spaces, which are directly connected with a central atrium. In such spaces, evaluation on auditory perception and noise annoyance should be performed in parallel with objective parametric measurements. The food-court area of CEPA Shopping Center, with a central atrium and a glass ceiling structure, in the capital city of Turkey, Ankara is chosen for the case. The aim of this study is to investigate the relationships between the users' subjective ratings of noise levels and the measured equivalent continuous sound pressure levels (Leq). In addition, the demographical differences and user profile variances, as well as the auditory perception classifications are investigated in this case space. The present acoustical indices are measured and then discussed by pointing out the architectural features of the case space, which are the central atrium, glass ceiling structure and the sound reflective material applications. The research methods include, noise measurements to obtain Leq and questionnaires to assess the subjective ratings and auditory perception of the users. This study mainly concentrates on the food-court space, which is within CEPA Shopping Center and displays the significant results regarding this space. These results show that Leq values vary by different day types (weekdays and weekends) and time of day, and the subjective ratings correlate well with these Leq variances. The most dominant sound perceived by the users was found to be the hum of voices. One other significant result implies that, subjective ratings of noise level becomes significant above 67 dBA and shows a sudden increase in the ratings. Furthermore, the time spent in the food-court area correlated significantly with noise annoyance ratings.