Examensarbeten för masterexamen


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  • Post
    Towards long-term health
    (2023) Berglund , Amelia; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Eriksson, Johanna; Strid, Marie
    Living with a chronic illness, recovering from long term sickness or seeing someone close to you cope with health issues has a direct impact on how we view ourselves as individuals and our surrounding environment. It’s a situation that can make us feel vulnerable, in a lack of power will disturb our ability to be in full control of our life. Suffering from mental illnesses will sooner or later lead to a state where our bodies are trying to self-regulate - meaning that we will naturally shift the view on how we experience certain environments and which type of space we require to feel supported, safe and secure. This so-called supportive environment could, although, look different depending on the individual’s physical and psychological condition - meaning that the type of needed space will most likely shift from person to person and when our state of mind changes over time. Theories in the field of landscape architecture say that there are in general eight different characteristics that could be found in supportive environments. This master thesis will identify and translate those characteristics into indoor spaces. The result are meant to visualize how this theory can be used as a guideline for creating spatial experiences where inclusiveness, wellbeing and healing is possible. Having this guideline in mind when designing could lead to a better understanding about how our choices affect the user and a greater knowledge about what a supportive environment actually looks like. The aim of this master thesis is to design a place where people in need get help to cope with their emotional connection to long term sickness. The project will serve as an additional function to the already existing medical care system and explore through theories how health promotive elements in healthcare design could be used to create a healing, inclusive environment where people get the right tools for making life feel meaningful, fulfilled and manageable again.
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    Empirical prediction of ground-borne vibration from railway systems; validating the HS2 model in Sweden, west coast
    (2023) Nordström, Jim; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Höstmad, Patrik; Hammarqvist, Mats
    Trains are becoming a more and more viable option as a fast, environmentally friendly travel choice. Along with this cities grows larger and civilizations becomes more urbanised. This results in an increase of human exposure to vibrations from trains, creating a need of vibration level predictions. Predictions enables at an early stage to be able to tell the impact of a new railway system. Whether residence buildings can be built at a certain proximity to the rail or hospitals, research facilities with vibration sensitive instruments, what trains with what speeds can pass and so on. One model to do this is the British empirical model named High Speed 2 (HS2). In Sweden, especially the west coast, the lithology differs from that of the UK as a result of the melting glaciers. Soft ground material, such as the Swedish glacial clay have tendencies to generate low frequency vibrational disturbances. This thesis is an evaluation of the HS2 model under Swedish conditions. It is limited to predicting the vibration levels in the ground at a certain distance from a surface running train. In 2021 a thesis work of Gustav Vågfelt was done were the HS2 model was implemented in Matlab and evaluated against a measurement data set at a Swedish site with help of Efterklang - part of AFRY [1] [15]. This thesis will continue on that work and in cooperation with Efterklang use the Matlab implementation to evaluate the model by conducting measurements at two different sites, one being post glacial fine sand and the other glacial clay. As there are still uncertainties in the model parameters a final conclusion of its precision can not yet be set. With the data available however the HS2 performs decent on the fine sand with quite consistent results and with the evaluation tools a table of values presenting the expected precision of the model is presented. The HS2 model did however not perform as well on the glacial clay. Because of this it was extended with an additional lithology to fit the Swedish glacial clay. This lithology performed excellent for the glacial clay site measurements, however that is expected as it originated from them. It was also tested on external measurement data from Greby, Skövde which also consisted of glacial clay. Here the extension of the model was less accurate. This indicates that measurement data from more glacial clay ground sites are needed to get a more accurate model extension.
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    Acoustic levitation in a cylindrical cavity; a modal superposition approach
    (2023) Johansson, Simon; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Ahrens, Jens
    A method has been developed for calculating the acoustic radiation force acting on a small spherical bead in a sound field within a rigid boundary cylindrical cavity, using a modal approach. Modes are selected by a method comparing their relative strengths, within a specified dB range below the strongest mode. The total sound field is calculated as the superposition of fields from different excitation points, each composed of a summation of mode shapes within the specified range. The total sound field is then used to calculate the force, by use of a previously established model. Three different simulated acoustic traps with a sound field excited by a plane transducer array at the bottom of the cylinder are presented. The traps are constructed by numerical optimization of the transducer phases and amplitudes such that the total sound field gives rise to converging forces at a designated position. One of the three simulated traps was also tested experimentally, where an acoustic trap at the designated position was not found. However, three other traps, one about 1 cm above the designated position, one in the center of the cylinder, and one about 5 mm offset from the center radially and in height, were found. Two of these alternate traps are also predicted by the developed model, which points towards the existence of a trap at the designated position as well, although hard to find by manual bead placement. The third found trap is not predicted by the model. Further research is needed to understand why that is, and how the model can be improved
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    Cost-effective spatial decomposition method solution for impulse response capture and auralization
    (2023) Simonsson, Victor; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Ahrens, Jens; Dombrovskis, Sergejs
    Spatial decomposition method (SDM) is a method to parameterize a spatial room impulse response into a scalar pressure value and a direction of arrival (DOA) for each time sample. SDM can be therefore be used to simulate acoustics in enclosed spaces and have proven effective when rendering to both headphones and loudspeaker arrays. The aim of this thesis was to design and build a low-cost SDM microphone array using MEMS microphones and investigate how different number of microphones affect auralization performance. All impulse response capture, encoding and decoding was implemented with Python, to be published as an open source library. Python modules were implemented to support rendering as both BRIRs and as virtual loudspeaker signals to be used in external auralization software. Due to hardware limitations the SDM array was limited to 6 microphones, although simulations were carried out to compare a 6 microphone array and a 12 microphone array. These were shown not to have any significant perceptual differences as expected from prior research. Listening tests were conducted where participants compared binaural room impulse responses decoded from SDM with a reference dummy head measurement. Two measurement situations were evaluated, clear line of sight and occlusion between source and receiver. The listening tests showed that neither measurement situation performed better than the other, relative to their respective reference and anchor. No clear difference between the ratings of different configurations of SDM encoding were found. All in all, this implementation proved sufficient at encoding and decoding binaural SDM. With additional post processing the audio quality will get even better
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    Evaluation of low-frequency façade insulation down to 20 Hz; measurement of low-frequency façade insulation down to 20 Hz and subjective assessment of synthesized cruise ship noise
    (2023) Björneklett, Oscar; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Forssén, Jens; Selamtzis, Andreas
    Low-frequency noise has become a growing concern due to its potential adverse effects on human health. However, existing measurement standards and calculation software typically do not cover frequencies below 50 Hz, despite the human hearing threshold extending down to 20 Hz. The knowledge gap regarding sound insulation in the lower frequency range has prompted the need for further research. Recent regulations allow for industrial noise to exceed permissible levels near dwellings as long as indoor requirements are met, creating opportunities for construction in previously unsuitable areas. An example of such a location is Värtahamnen in Stockholm, where cruise ships regularly dock and generate noise from their ventilation systems and onboard electricity generation. These ships are expected to produce low-frequency noise that may pose challenges for nearby planned dwellings. This raises questions about evaluating low-frequency sound insulation and establishing reliable measurement methods, considering that sound pressure levels within rooms can vary significantly due to room modes. This thesis utilizes a field-tested measurement method to assess the sound insulation of façades down to 20 Hz. The measurements also include a subjective assessment of synthesized cruise ship noise and its perception by the auditory system. Additionally, a finite element model was utilized to analyze room modes and gain further insights into their influence on the acoustic environment. The results of the measurements indicate that common façade structures exhibit a moderate sound insulation capability down to 20 Hz. Among the various parameters that affect sound insulation below 100 Hz, room modes and windows were found to have the most significant impact. The subjective assessment revealed that when the synthesized cruise ship noise is barely audible in the receiving room, its frequency contents below 80 Hz lie below the human hearing threshold; however, as the noise levels increase to the point of being disturbing, this frequency limit is lowered to 31,5 Hz. These results indicate that modern façades may have adequate sound insulation below 50 Hz considering the human hearing threshold. However, achieving this requires careful planning and construction.