| 1. |
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| 2. |
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| 3. |
- Arvelius, Per, et al.
(author)
-
Genetic analysis of a temperament test as a tool to select against everyday life fearfulness in Rough Collie
- 2014
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In: Journal of Animal Science. - : Oxford University Press (OUP). - 0021-8812 .- 1525-3163. ; 92, s. 4843-4855
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Journal article (peer-reviewed)abstract
- Fear-related problems are common among Rough Collies in Sweden. Annually, on average, >200 Rough Collies are subjected to the dog mentality assessment (DMA), a temperament test during which 33 behavioral reactions are rated. Previous research has shown that a dog's DMA result can be condensed into 5 underlying personality traits. The aim of the study was to evaluate if it is possible to use the DMA for selection for temperament in Swedish Rough Collies, in particular to decrease everyday life fearfulness. We also wanted to compare 2 methods to compute the personality traits: summated scales (SS) and factor scores (FS). The DMA data for 2,953 Rough Collies were used to estimate genetic parameters for the 5 personality traits (both SS and FS), using a linear animal model including fixed effects of sex, year and month of test, and random effects of litter, judge, test occasion, genetic effect of the individual, and residual. Age at test was included as linear and quadratic regressions. The DMA personality trait heritability estimates ranged from 0.13 to 0.25. The SS showed greater or equal heritability estimates compared with the FS. To validate the DMA, data on everyday life behavior of 1,738 Rough Collies were collected using an extended version of the Canine Behavioral Assessment and Research Questionnaire. Each dog's questionnaire result was condensed into 18 underlying behavioral subscales. Genetic parameters for the subscales were estimated using a linear animal model, including a fixed effect of sex and random genetic effect of the individual and residual. Age when the questionnaire was completed was included as linear and quadratic regressions. Heritability estimates for the questionnaire subscales were 0.06 to 0.36. There were high and significant genetic correlations between DMA personality traits and questionnaire subscales. For instance, the DMA personality trait Curiosity/Fearlessness correlated strongly genetically to the questionnaire subscale Non-social fear (-0.70), DMA Sociability to Stranger-directed interest (0.87) and Stranger-directed fear (-0.80), DMA Playfulness to Human-directed play interest (0.63), and DMA Chase-proneness to Chasing (0.73). We could not detect any obvious difference in validity between DMA SS and FS. We conclude that the DMA is an effective tool for selection of breeding animals with the goal to decrease everyday life fearfulness among Swedish Rough Collies. The DMA can also be used for breeding for other traits. The SS method seems to perform at least as good the FS method.
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| 4. |
- Arvelius, Per, et al.
(author)
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Good Possibilities to Select Against Fearfulness in Rough Collie
- 2014
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Other publication (other academic/artistic)abstract
- Fear-related problems are common among Swedish Rough Collies. Genetic analyses were performed on 4 composite behavioral traits based on 2953 Rough Collie results from a temperament test. Heritabilities ranged from 0.13-0.25. Validation of the test was done using a dog owner questionnaire, which generated information about everyday life behavior for 1738 Rough Collies. There were high and significant genetic correlations between traits measured in the test, and the everyday life behavior of the dogs as described by the owners. For instance, Curiosity/fearlessness in the test was negatively genetically correlated with Nonsocial fear in the questionnaire (-0.70, SE 0.10). We conclude that data from the analyzed test is possible to use for selection to decrease everyday life fearfulness in the Swedish Rough Collie population.
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| 5. |
- Arvidsson, Emma, et al.
(author)
-
Acoustic design of ordinary rooms using absorbers and diffusers
- 2020
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In: Proceedings of 2020 International Congress on Noise Control Engineering, INTER-NOISE 2020. - 9788994021362
-
Conference paper (peer-reviewed)abstract
- With different activities in a room, room acoustic requirements differ and when the acoustic requirements are different, acoustic treatment must be adapted. This study focuses on room acoustics in ordinary public rooms such as classrooms and offices. By tradition the acoustic treatment in these rooms is an absorbent ceiling. Experiments have been carried out in a classroom where the baseline in the acoustic treatment was a highly absorptive acoustic ceiling. This treatment has then been combined with different configurations of diffusers and wall absorbers where the coverage and pattern of the different treatments has been tested to evaluate their effect on the room acoustic parameters. Furthermore, several configurations with different diffuser directionality have been evaluated. The room acoustic parameters reverberation time, speech clarity and sound strength were assessed. The results show a clear correspondence in the room acoustic parameters for the different treatments used, as well as a frequency dependence. Here we discuss the interpretation of these results and how this new information can be used to obtain the room acoustic requirements for a specific activity.
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| 6. |
- Arvidsson, Emma, et al.
(author)
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Diffusers in public ordinary rooms
- 2019
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In: InterNoise 19, Madrid, Spain. - 9788487985317 ; , s. 5453-5461
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Conference paper (other academic/artistic)abstract
- Traditionally, the room acoustic properties in an ordinary public room are defined by only one parameter, the reverberation time. However, research has showed that additional room acoustic parameters as sound strength and speech clarity are necessary to consider in order to achieve good acoustic conditions. In a room with acoustical ceiling treatment the effects of furniture and interiors on the room acoustic parameters are significant. In addition, by using diffusers with directional properties it is possible to individually control the room acoustic parameters. Room acoustical measurements have been carried out in a reverberation chamber with suspended absorbing ceiling and directional diffusing objects. The effect of different diffuser configurations has been examined regarding reverberation time, speech clarity and sound strength. The evaluation shows that the orientation and the amount of the diffusing elements have a significant influence on the room acoustic parameters and can be used to fine-tune the acoustical conditions in public ordinary rooms with an existing acoustic ceiling treatment. This paper presents a study showing how diffusers can be used to contribute to an improved sound environment in public ordinary rooms with an acoustic ceiling.
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| 7. |
- Arvidsson, Emma, et al.
(author)
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Optimization of sound absorbing ceilings
- 2018
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In: 47th International Congress and Exposition on Noise Control Engineering (INTERNOISE 2018). - 9781510873032
-
Conference paper (peer-reviewed)abstract
- The typical acoustical treatment in ordinary rooms such as classrooms, offices, conference rooms etc is an absorbing suspended ceiling. Due to the non-uniform distribution of the absorbing material the sound field at steady-state and during sound decay is far from the ideal conditions assumed in the diffuse field theory. Especially during the sound decay, the degeneration of the sound field emphasizes the shortcomings of the diffuse field assumption. On the other hand, the absorbing properties of sound absorbing ceilings are determined under diffuse field conditions according to the standard ISO 354. The outcome of this measurement in the form of an absorption coefficient is often used as input data in calculation or simulation models. This means that the absorbing properties of the ceilings are characterized under circumstances that are hardly ever encountered in practice. The directional scattering effect of furniture and other interior objects is another circumstance that has to be considered to understand the interaction between the absorbing ceiling and the sound field in rooms with ceiling treatment. In this paper the outline of a project is presented that deals with how to optimize the acoustical properties of ceilings in order to achieve certain room acoustic target values related to reverberation time, speech clarity and sound strength.
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| 8. |
- Arvidsson, Emma, et al.
(author)
-
Pattern and orientation of diffusers in rooms with an absorbent ceiling
- 2019
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In: Proceedings of the 23rd International Congress on Acoustics : Integrating 4th EAA Euroregio 2019 - Integrating 4th EAA Euroregio 2019. - 2226-7808 .- 2415-1599. - 9783939296157 ; 2019-September, s. 2281-2288
-
Conference paper (peer-reviewed)abstract
- Lately have the demands on good room acoustics in public ordinary rooms increased. Traditionally has only reverberation time been considered in this type of rooms but complementary parameters as sound strength and speech clarity are more commonly used today. This trend naturally implies higher demands on the acoustic treatment. Typical for public ordinary rooms is to use an absorbent ceiling. One way to further improve the acoustic properties is to complement the ceiling treatment with diffusers. To investigate the effect of combining these two types of acoustic treatments have measurements been carried out combing different setups of diffusers in a reverberant room with an absorbent ceiling. The impact on reverberation time, speech clarity and sound strength has been studied. In this paper we present how diffusers can be used in order to improve the acoustic properties in a public ordinary room with an absorbent ceiling and how the pattern and orientation of diffusers can be used to adjust different acoustic parameters.
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| 9. |
- Arvidsson, Emma, et al.
(author)
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Quantification of the absorption and scattering effects of diffusers in a room with absorbent ceiling
- 2021
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In: Buildings. - : MDPI AG. - 2075-5309. ; 11:12
-
Journal article (peer-reviewed)abstract
- In ordinary public rooms, such as classrooms and offices, an absorbent ceiling is the typical first acoustic action. This treatment provides a good acoustic baseline. However, an improvement of specific room acoustic parameters, operating for specific frequencies, can be needed. It has been seen that diffusing elements can be effective additional treatment. In order to choose the right design, placement, and quantity of diffusers, a model to estimate the effect on the acoustics is necessary. This study evaluated whether an SEA model could be used for that purpose, particularly for the cases where diffusers are used in combination with an absorbent ceiling. It was investigated whether the model could handle different quantities of diffusing elements, varied diffusion characteristics, and varied installation patterns. It was found that the model was sensitive to these changes, given that the output from the model in terms of acoustic properties will be reflected by the change of diffuser configuration design. It was also seen that the absorption and scattering of the diffusers could be quantified in a laboratory environment: a reverberation chamber. Through the SEA model, these quantities could be transformed to a full-scale room for estimation of the room acoustic parameters.
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| 10. |
- Arvidsson, Emma, et al.
(author)
-
Subjective experience of speech depending on the acoustic treatment in an ordinary room
- 2021
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In: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 18:23
-
Journal article (peer-reviewed)abstract
- In environments such as classrooms and offices, complex tasks are performed. A satisfac-tory acoustic environment is critical for the performance of such tasks. To ensure a good acoustic environment, the right acoustic treatment must be used. The relation between different room acoustic treatments and how they affect speech perception in these types of rooms is not yet fully under-stood. In this study, speech perception was evaluated for three different configurations using ab-sorbers and diffusers. Twenty-nine participants reported on their subjective experience of speech in respect of different configurations in different positions in a room. They judged sound quality and attributes related to speech perception. In addition, the jury members ranked the different acoustic environments. The subjective experience was related to the different room acoustic treatments and the room acoustic parameters of speech clarity, reverberation time and sound strength. It was found that people, on average, rated treatments with a high degree of absorption as best. This configura-tion had the highest speech clarity value and lowest values for reverberation time and sound strength. The perceived sound quality could be correlated to speech clarity, while attributes related to speech perception had the strongest association with reverberation time.
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| 11. |
- Arvidsson, Emma, et al.
(author)
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The Difference in Subjective Experience Related to Acoustic Treatments in an Ordinary Public Room : A Case Study
- 2021
-
In: Acoustics. - : MDPI AG. - 2624-599X. ; 3
-
Journal article (peer-reviewed)abstract
- In ordinary public rooms absorbent ceilings are normally used. However, reflective material such as diffusers can also be useful to improve the acoustic performance for this type of environment. In this study, different combinations of absorbers and diffusers have been used. The study investigates whether a test group of 29 people perceived sound in an ordinary room differently depending on the type of treatment. Comparisons of the same position in a room for different configurations as well as different positions within one configuration were made. The subjective judgements were compared to the room acoustic measures T20, C50 and G and the difference in the values of these parameters. It was found that when evaluating the different positions in a room, the configuration including diffusers was perceived to a greater extent as being similar in the different positions in the room when compared to the configuration with absorbers on the walls. It was also seen that C50 was the parameter that mainly affected the perception, with the difference needing to be 2 dB to recognize a difference. However, the room acoustic measurements could not fully explain the differences obtained in perception. In addition, the subjective sound image created by different types of treatments was also shown to have an important impact on the perception.
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| 12. |
- Arvidsson, Emma, et al.
(author)
-
The Effect on Room Acoustical Parameters Using a Combination of Absorbers and Diffusers : An Experimental Study in a Classroom
- 2020
-
In: Acoustics. - : MDPI AG. - 2624-599X. ; 2:3
-
Journal article (peer-reviewed)abstract
- Several room acoustic parameters have to be considered in ordinary public rooms, such as offices and classrooms, in order to present the actual conditions, thus increasing demands on the acoustic treatment. The most common acoustical treatment in ordinary rooms is a suspended absorbent ceiling. Due to the non-uniform distribution of the absorbent material, the classical diffuse field assumption is not fulfilled in such cases. Further, the sound scattering effect of non-absorbing objects such as furniture are considerable in these types of rooms. Even the directional characteristic of the sound scattering objects are of importance. The sound decay curve in rooms with absorbent ceilings often demonstrate a double slope. Thus, it is not possible to use reverberation time as room parameter as a representative standalone acoustic measure. An evaluation that captures the true room acoustical conditions therefore needs supplementary parameters. The aim of this experimental study is to show how various acoustical treatments affect reverberation time T20, speech clarity C50 and sound strength G. The experiment was performed in a mock-up of a classroom. The results demonstrated how absorbers, diffusers and scattering objects influence room acoustical parameters. It is shown that to some extent the parameters can be adjusted individually by using different treatments or combination of treatments. This allows for the fine-tuning of the acoustical conditions, in order to fulfill the requirements for achieving a high-quality sound environment.
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| 13. |
- Autio, Hanna, et al.
(author)
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A Novel Algorithm for Directional Scattering in Acoustic Ray Tracers
- 2023
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In: Acoustics. - 2624-599X. ; 5:4, s. 928-947
-
Journal article (peer-reviewed)abstract
- It is vital to consider acoustic scattering when using geometrical acoustic simulation techniques, such as ray tracing. However, there are few methods for modelling scattering, and most rely on strong assumptions of uniformity on the distribution of scattered energy. In this paper, a model for directional scattering in ray tracers is presented. The model is based on an idealized model of a 1D scatterer, which is then used to extend the most commonly used scattering algorithm in ray tracers today. The developed algorithm is implemented in a ray tracer and tested to evaluate its performance compared to existing methods. It is found that the directional scattering algorithm can be used to replicate measured effects on room acoustic parameters caused by changes in the orientation of 1D scatterers.
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| 14. |
- Bjurström, Erling, 1949-, et al.
(author)
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Kreativitet
- 1991
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In: Staten Ungdomsråds Årsbok om ungdom 1991. - Stockholm : Statens ungdomsråd.
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Book chapter (pop. science, debate, etc.)
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| 15. |
- Björgvinsson, Erling, et al.
(author)
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Prototyping Futures
- 2012
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Reports (other academic/artistic)abstract
- Prototyping Futures gives you a glimpse of what collaborating with academia might look like. Medea and its co-partners share their stories about activities happening at the research centre – projects, methods, tools, and approaches – what challenges lie ahead, and how these can be tackled. Examples of highlighted topics include: What is a living lab and how does it work? What are the visions behind the Connectivity Lab at Medea? And, how can prototyping-methods be used when sketching scenarios for sustainable futures? Other topics are: What is the role of the body when designing technology? What is collaborative media and how can this concept help us understand contemporary media practices? Prototyping Futures also discusses the open-hardware platform Arduino, and the concepts of open data and the Internet of Things, raising questions on how digital media and connected devices can contribute to more sustainable lifestyles, and a better world.
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| 16. |
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| 17. |
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| 18. |
- Brunskog, Jonas, et al.
(author)
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Absorption and scattering by perforated facings with periodic narrow slits
- 2022
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 151:3, s. 1847-1859
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Journal article (peer-reviewed)abstract
- This paper develops a theory for the sound absorption and scattering of perforated slit absorbers.A rigid plane, perforated periodically in one dimension with absorbing slits, scatters incoming sound waves as discrete wave components in different directions. The absorbing slits are assumed to be line-like in the sense that their width is much shorter than the wavelengths.The equation for the sound field is solved in the wavenumber domain. The slits are described with an impedance description, assuming local reaction of the slits (typically a Helmholtz resonator).The solution is found by means of an inverse transform, back to the spatial domain. This results in an explicit formulation of the sound field, including a sum consisting of components that either radiate energy in discrete directions or are surface waves.A similar sum is also included in a term that can be interpreted as radiation impedance. The explicit expressions for the absorption and scattering coefficients are found with the aid of the radiating part of the scattered and reflected field.Numerical results of the absorption and scattering coefficients are presented. The result is verified with finite element method and compared with the result from an alternative general formulation of the problem.
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| 19. |
- Carlén, Emma, et al.
(author)
-
Random regression models for genetic evaluation of clinical mastitis in dairy cattle
- 2009
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In: Animal. - 1751-7311 .- 1751-732X. ; 3, s. 1100-1108
-
Journal article (peer-reviewed)abstract
- A genetic analysis of longitudinal binary clinical mastitis (CM) data recorded on about 90000 first-lactation Swedish Holstein cows was carried out using linear random regression models (RRM). This method for genetic evaluation of CM has theoretical advantages compared to the method of linear cross-sectional models (CSM), which is currently being used The aim of this study was to investigate the feasibility and suitability of estimating genetic parameters and predicting breeding values for CM with a linear sire RRM. For validation purposes, the estimates and predictions from the RRM were compared to those from linear sire longitudinal multivariate models (LMVM) and CSM. For each cow, the period from 10 days before to 241 days after calving was divided into four 1-week intervals followed by eight 4-week intervals. Within each interval, presence or absence of CM was scored as '1' or '0' The linear RRM used to explain the trajectory of CM over time included a set of explanatory variables plus a third-order Legendre polynomial function of time for the sire effect The time-dependent heritabilities and genetic correlations from the chosen RRM corresponded fairly well with estimates obtained from the linear LMVM for the separate intervals. Some discrepancy between the two methods was observed, with the more unstable results being obtained from the linear LMVM. Both methods indicated clearly that CM was not genetically the same trait throughout lactation. The correlations between predicted sire breeding values from the RRM, summarized over different time periods, and from linear CSM were rather high. They were, however, less than unity (0.74 to 0.96), which indicated some re-ranking of sires. Sire curves based on the time-specific breeding values from the RRM illustrated differences in intercept and slope among the best and the worst sires. To conclude, a linear sire RRM seemed to work well for genetic evaluation purposes, but was sensitive for estimation of genetic parameters.
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| 20. |
-
Circulation of Knowledge : Explorations in the History of Knowledge
- 2018
-
Editorial collection (other academic/artistic)abstract
- Historians have long been interested in knowledge—its nature and origin, and the circumstances under which it was created—but it has only been in recent years that the history of knowledge has emerged as an academic field in its own right.In "Circulation of Knowledge", a group of Nordic scholars explore a range of theoretical and methodological approaches to this new and exciting area of historical research. The question of knowledge in motion is central to their investigations, and especially how knowledge is transformed when it circulates between different societal arenas, literary genres, or forms of media.Reflecting on twelve empirical studies, from sixteenth century cartography to sexology in the 1970s, the authors make a significant contribution to the growing international research on the history of knowledge.
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| 21. |
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| 22. |
- Eken Asp, Helena, et al.
(author)
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Breed differences in everyday behaviour of dogs
- 2015
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In: Applied Animal Behaviour Science. - : Elsevier BV. - 0168-1591 .- 1872-9045. ; 169, s. 69-77
-
Journal article (peer-reviewed)abstract
- The domestication of the dog and the ensuing breed creation has resulted in a plethora of dog breeds that differ not only in morphology but also in terms of behaviour. In addition, a majority of the dogs today are no longer utilized for their working ability, but are mainly kept as companion animals. The main aim of this study was to estimate breed differences in everyday behaviour traits, as well as to study the phenotypic correlations between these traits. Dog owners described their dogs' everyday behaviour in a questionnaire. The responses to the questions were combined into 18 behavioural subscale scores (BSS). After editing, the material included dog owner responses for 3591 dogs from 20 different breeds. The breeds represent both working and non-working breeds.We can conclude that breed (and grouping into working vs non-working breeds), age and sex had significant effects on many everyday behaviour traits. The working breeds were about 10% more trainable, showed 30% more interest in playing with humans and were 10-60% less fearful. Furthermore, our results showed that fearful dogs were more aggressive, whereas more social dogs were less fearful and less aggressive. We also found that dogs that were more eager to play with humans were also easier to train. (C) 2015 Elsevier B.V. All rights reserved.
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| 23. |
- Eken Asp, Helena, et al.
(author)
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Genetics of Aggression, Fear and Sociability in Everyday Life of Swedish Dogs
- 2014
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Conference paper (other academic/artistic)abstract
- Most potential dog owners are looking for a non-aggressive, non-fearful, social and easily trained dog that functions well in everyday life. Despite this, most studies of genetic components for behavior traits have mainly focused on analyzing results from behavior tests and not everyday behavior data. The aim of this study was to estimate genetic parameters for aggression, fear, sociability and trainability in everyday life by using a questionnaire to assess information of the dog's everyday behavior. The genetic analysis included 3128 records distributed over 14 breeds. The effect of breed, sex and age were adjusted for in the estimations of genetic parameters. The estimated heritabilities ranged between 0.08 and 0.38, with the highest heritability found for human-directed play interest. Positive genetic correlations were found between aggression and fear traits. Sociability traits showed a negative genetic correlation with both aggression and fear traits.
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| 24. |
- Emsfors, Erling, 1951-, et al.
(author)
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Skillnader mellan ekonomistyrsystem, typ av situation och prestation i småföretag
- 2001
-
Reports (other academic/artistic)abstract
- Studies have shown mixed results whether there is a positive relationship between small businesses’ management accounting information and their success. In uncertain situations decision-makers tend to rely on their visions and experiences rather than on formal decision-making models. Entrepreneurship is based on uncertainty and innovation, and may therefore be inhibited by management accounting aiming at reducing uncertainty. Small businesses are partly entrepreneurs, partly ‘livelihood businesses’. The question in this paper is: Are there systems of management accounting in small businesses that are less or more effective in different situations? In a cluster analysis of 124 small businesses we found four relevant systems of management accounting regarding line of business. Moreover, there were significant differences in the market effectiveness when the uncertainty of the situation increased. Finally, the difference between the four systems was significant in the combination of strategic behaviour/pay to board/MD.
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| 25. |
- Emsfors, Erling, et al.
(author)
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Skillnader mellan ekonomistyrsystem, typ av situation och prestation i småföretag
- 2001
-
Book (other academic/artistic)abstract
- Studies have shown mixed results whether there is a positive relationship between small businesses’ management accounting information and their success. In uncertain situations decision-makers tend to rely on their visions and experiences rather than on formal decision-making models. Entrepreneurship is based on uncertainty and innovation, and may therefore be inhibited by management accounting aiming at reducing uncertainty. Small businesses are partly entrepreneurs, partly ‘livelihood businesses’. The question in this paper is: Are there systems of management accounting in small businesses that are less or more effective in different situations? In a cluster analysis of 124 small businesses we found four relevant systems of management accounting regarding line of business. Moreover, there were significant differences in the market effectiveness when the uncertainty of the situation increased. Finally, the difference between the four systems was significant in the combination of strategic behaviour/pay to board/MD.
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| 26. |
- Gerhardsson, Lars, 1952, et al.
(author)
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Noise disturbances in daycare centers before and after acoustical treatment.
- 2013
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In: Journal of environmental health. - 0022-0892. ; 75:7, s. 36-40
-
Journal article (peer-reviewed)abstract
- The authors' aim was to study noise-related problems in personnel at Swedish daycare centers. The authors' study comprised staff (N = 81) who completed a questionnaire (noise, illumination, indoor climate, hearing problems) at five daycare centers with noise problems. After basic and activity sound measurements, absorbers were attached to the ceilings and to two adjacent walls in the playing and dining rooms. Thereafter, basic and activity sound measures were repeated and the questionnaire was also repeated six months later. The acoustical treatment reduced the sound pressure levels by 2 to 6 dB in the playing rooms and by 0 to 3 dB in the dining rooms. The reverberation time was reduced by 20% to 50%. After the treatment the perceived noise disturbance level decreased slightly but not significantly and the proportion of the staff who often or very often planned the daily activities to reduce the noise level had decreased from about 39% to 25%. Similarly, the percentage that often or very often had a need for silence after work had decreased from 42% to 37%.
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| 27. |
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| 28. |
- Hellström, Björn, 1959-, et al.
(author)
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Room acoustic design in open-plan offices
- 2009
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In: Proceedings of the Institute of Acoustics Volume 31 Pt.3. - St. Albans, United Kingdom : Institute of Acoustics. - 9781615676804 ; , s. 2954-2959
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Conference paper (peer-reviewed)abstract
- In a Nordic cooperation project the acoustical conditions in open-plan offices was investigated. Measurements have been carried out in five open plan offices accompanied with an inquiry gathering the subjective judgments by the staff. A program for the acoustical measurements was designed specifying how to perform the measurements and which type of parameters to measure. The acoustical parameters included in the measurements are Reverberation time T20, Early Decay Time (EDT), Clarity (C50), Speech transmission index (STI), Speech intelligibility index (SII), Privacy Index (PI), Rate of spatial decay of sound pressure levels per distance doubling (DL2 ), Excess of sound pressure level with respect to a reference curve (DLf), background noise levels in occupied and unoccupied offices. In two of the offices are furbishment program was carried out. Measurements as well as questionnaire were accomplished after refurbishment. The effect on room acoustic parameters DL2 and DLf and on subjective judgments by the staff will be presented in this paper.
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| 29. |
- Holmberg, Dag, et al.
(author)
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Absorption and radiation impedance of finite absorbing patches
- 2003
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In: Acta Acustica united with Acustica. - 1436-7947. ; 89:3, s. 406-415
-
Journal article (peer-reviewed)abstract
- A variational formulation is used to calculate the sound absorption in order to incorporate the interaction between several absorbing patches of arbitrary shape. In particular, this formulation is applied to small periodic patches. The absorption characteristics are governed by the radiation impedance, Z(r), which is a function of the absorber's geometry and the incidence angle, together with the surface impedance of the absorber. The behaviour of Z(r) is evaluated numerically for a number of typical configurations, and the effect on the statistical absorption coefficient, alpha(stat) is calculated. The evaluations stress that alpha(stat) is regulated by the interaction between Z(r) and the impedance of the absorber. A comparison is made of results from measurements and calculations performed on the measurement set-up.
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| 30. |
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| 31. |
- Johansson, Ann-Charlotte, et al.
(author)
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Evaluation of drum sound with ISO tapping machine
- 2005
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In: Building Acoustics. - : SAGE Publications. - 1351-010X .- 2059-8025. ; 12:2, s. 59-84
-
Journal article (peer-reviewed)abstract
- A branch norm, EPLF NORM 021029-3,1 has been established for measuring drum sound on laminate floor coverings. ‘Drum sound’ refers to the sound occurring when an object, e.g. a foot, strikes the flooring in the room in which the receiving ear is located. The norm evaluates the subjective perception of the drum sound's loudness using the ISO tapping machine. A round-robin study of the norm is reported along with the results of a paired comparison listening test using the same floor coverings. The article discusses general aspects of evaluation measures, tapping machines, test environments, etc., that need to be considered when measuring drum sound on various floor coverings, such as linoleum, wood parquet and laminate. It is concluded that loudness as measured according to ISO 532B correlates the best with the subjective perception of the drum sound's loudness. The tapping machine can be used to excite hard floor coverings to produce the drum sound, but should be used with caution in studying low-level drum sounds due to the tapping machine's inherent mechanical noise.
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| 32. |
- Johansson, Ann-Charlotte, et al.
(author)
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Prediction of subjective response from objective measurements applied to walking sound
- 2004
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In: Acta Acustica united with Acustica. - 1436-7947. ; 90:1, s. 161-170
-
Journal article (peer-reviewed)abstract
- This paper discusses prediction of the subjective response to walking sound - also called drum sound - based on differences in objective measurements. 'Walking sound' refers to the sound heard when someone is walking in the same room as the listener. Walking sound has attracted interest in recent years, particularly due to an increased use of thin floating floor constructions, such as veneer or laminate flooring, which can produce loud and sharp walking sound. A paired comparison test was performed in laboratory where listeners were asked which of the walking sounds was most disturbing. The response was analysed using a modified Bradley and Terry model allowing ties. Various measures, such as loudness according to ISO 532B, were tested against the subjective response using linear regression. The difference in 10-percentile loudness, N-10, between two stimuli was shown to predict the subjective response better than, for example, A-weighted sound pressure level. A difference of about 8% in N-10 resulted in 50% of the subjects noticing a difference. The methodology used is applicable in situations when objective measures that have subjective counterparts are sought. Although the method is based on relative observations, an absolute ranking can be obtained by using a reference or a well-defined recording situation.
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| 33. |
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| 34. |
- Kronander, Håkan, 1953-
(author)
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Diagnostic and Prognostic Value of Exercise Electrocardiographic Test Variables in Coronary Artery Disease
- 2009
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Doctoral thesis (other academic/artistic)abstract
- The diagnostic performance of conventional analysis of the exercise electrocardiographic (ECG) test for the detection of coronary artery disease (CAD) is limited to 70-75%. The exercise ECG test is the most widely used non-invasive method for assessing CAD and even a small improvement in the diagnostic performance is important. The objective of this thesis was to investigate the diagnostic performance of the exercise ECG test for diagnosis of CAD and the prognostic performance of the test for predicting acute myocardial infarction (AMI), in both men and women. In the diagnostic part of the present study, aimed at finding the optimal diagnostic information during the exercise and recovery phase, 1,877 electrocardiograms selected from 8,322 consecutive patients undergoing a routine exercise test on bicycle ergometer were evaluated. CAD was verified angiographically in 669 patients and excluded in 1,208 patients, by angiography (119 patients), by myocardial scintigraphy (250 patients), or on clinical grounds (839 patients). The diagnostic performance of ST-segment amplitude, and the difference between heart rate (HR) matched recovery and exercise ST-segment amplitudes (ST/HR difference), were evaluated by constructing receiver operating characteristic (ROC) curves for each sample point every 12th second during 10 minutes of recovery as well as the last 4 minutes of exercise for the ST-segment amplitude. ST-segment amplitude performed better after exercise than during exercise and best within the first 2 minutes of recovery. Its diagnostic ability did not differ from the ST/HR difference. Both methods performed better in men than in women and the diagnostic information appeared mainly in leads I, -aVR, II, V4, V5 and V6. The effect of different sampling rates (1, 2 and 5 samples/min) on the CAD discrimination ability of ST/HR loop area was evaluated by using ROC curves. A use of sampling frequency below 2 samples/min resulted in a significantly diminished diagnostic performance. ST-segment and ST/HR variables were compared during exercise and during early post-exercise recovery in terms of diagnostic discrimination capacity and optimal partition values. Discriminating capacity of the methods was evaluated by the use of ROC areas. Partition values, providing the combination of the best sensitivity and specificity, were established. The results demonstrate that analysis of post-exercise ST/HR hysteresis offers the most accurate and gender indifferent identification of patients with CAD. The prognostic part of the study included 8,317 of the 8,322 patients and covered a mean follow-up period of 9.5 years. This part of the study was used to evaluate the long-term prognostic value of ST/HR hysteresis in predicting AMI and all-cause mortality in men and women. ST/HR hysteresis appears to improve the prognostic ability of an exercise ECG test for AMI and all-cause mortality in a long term perspective compared to conventional ST-segment and ST/HR indicators in both genders and clearly more markedly in women.
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| 35. |
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| 36. |
- Nilsson, Andreas, 1971-
(author)
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Projektledning i praktiken : Observationer av arbete i korta projekt
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Project management used to be described as rational and well structured - a notion that builds on a traditional view that project management is about planning, budgeting and controlling. Nevertheless, it has been questioned if this is a full description. Even though project management techniques were developed for large projects, those techniques and models are used today in small projects of short duration - projects that are quite dissimilar to the large ones. The present study takes a practice perspective to investigate what project managers do when they lead such short projects. Its observations and interviews are used to analyze what happens in the everyday life of project managers. Using classical managerial behaviour studies as a foundation, seen through a practice perspective lens, the study finds that the work of project managers in a software development project is fragmented – their time is filled with formal and informal meetings of different kinds and efforts to resist disturbances in the project.Three challenges were found in the project manager’s work. The first was to Understand: to create meaning. The plans were clearly defined at the start of the project but as the goals were later re-defined, it was scarcely possible to finalize them before delivery. Contrary to the traditional view that plans are inflexible, these plans were discussed, negotiated and interpreted throughout the project. This was the continuous work of creating both meaning in the plans and a common understanding of the project.The second challenge was to Order/coordinate: to manage resources. The project manager reacted to emerging issues rather than acting to prevent things from happening. These reactions led to creative ways of managing and finding solutions to problems. One important way of managing new or changed conditions was to reorganize resources to cover the needs of different teams. The meetings played a central role in this work as arenas for negotiating resources, which became especially evident in times of stress or high workload.The third challenge was to Make it in time: to manage time. Time is a central aspect of project management as projects are temporary organizations; they have a beginning and an end. Previous research has found a point in time, in the middle of a project, when the team starts to feel pressured and stressed about meeting their deadlines. For project managers there is always a struggle to manage time, as dates for delivery are one of the things in a project that are not negotiable. In short-duration projects where projects follow each other seriatim, there is an almost constant feeling of urgency; stress and pressure. The project manager used experiential data to determine and plan the amount of time that would be needed to manage changes in the project, intending that the slack created would enable the project to deliver on time. Although changes and deviations were expected, the project manager rarely knew beforehand what they were or when they would come.The three challenges, previously described as separated from each other, were observed to be all managed simultaneously. The site, the practitioner and the practices influence daily work practice.
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| 37. |
- Nilsson, Erling, et al.
(author)
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Acoustic design of open-plan offices
- 2010
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Reports (other academic/artistic)abstract
- The acoustic conditions in open-plan offices were investigated in a Nordic cooperation project. Measurements were carried out in five open-plan offices along with a questionnaire to gather the staff’s subjective judgments.A programme for the acoustic measurements was drawn up, specifying how to perform the measurements and which type of parameters to measure.The acoustic parameters included are Reverberation time T20, Early decay time (EDT), Clarity (C50), Speech transmission index (STI), Speech intelligibility index (SII), Privacy index (PI), Rate of spatial decay of sound pressure levels per distance doubling (DL2 ), Excess of sound pressure level with respect to a reference curve (DLf), and background noise levels in occupied and unoccupied offices.A refurbishment programme was carried out in two of the offices. Measurements were performed after refurbishment and a questionnaire was completed. It is concluded that parameters relating to sound propagation, such as DL2 and DLf, are appropriate for the acoustic evaluation of open-plan spaces.A refurbishment programme was carried out in two open-plan offices. It has been shown that DL2 and DLf are sensitive to the acoustic treatment carried out and that they also reflect an improvement in the subjective judgment as regards the acoustic environment in general. Moreover, these parameters can be converted into a (comfort) radius indicating the distance for achievement of a certain reduction of the sound level from a sound source.This application could serve as a practical tool for the acoustic planning of open-plan offices.
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| 38. |
- Nilsson, Erling, et al.
(author)
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An energy model for the calculation of room acoustic parameters in rectangular rooms with absorbent ceilings
- 2021
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In: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 11:14
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Journal article (peer-reviewed)abstract
- The most common acoustical treatment of public rooms, such as schools, offices, and healthcare premises, is a suspended absorbent ceiling. The non-uniform distribution of the absorbent material, as well as the influence of sound-scattering objects such as furniture or other interior equipment, has to be taken into account when calculating room acoustic parameters. This requires additional information than what is already inherent in the statistical absorption coefficients and equivalent absorption areas provided by the reverberation chamber method ISO 354. Furthermore, the classical diffuse field assumption cannot be expected to be valid in these types of rooms. The non-isotropic sound field has to be considered. In this paper, a statistical energy analysis (SEA) model is derived. The sound field is subdivided into a grazing and non-grazing part where the grazing part refers to waves propagating almost parallel to the suspended ceiling. For estimation of all the inherent parameters in the model, the surface impedance of the suspended ceiling has to be known. A method for estimating the scattering and absorbing effects of furniture and objects is suggested in this paper. The room acoustical parameters reverberation time T20, speech clarity C50, and sound strength G were calculated with the model and compared with calculations according to the classical diffuse field model. Comparison with measurements were performed for a classroom configuration. With regard to all cases, the new model agrees better with measurements than the classical one.
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| 39. |
- Nilsson, Erling
(author)
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Decay processes in rooms with non-diffuse sound fields Part I: Ceiling treatment with absorbing material
- 2004
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In: Building Acoustics. ; 11:1, s. 39-60
-
Journal article (peer-reviewed)abstract
- The decay process in rooms with non-diffuse sound fields was the subject of this investigation. A rectangular room with high absorption at the ceiling and low absorption at the walls and floor constituted the basic configuration for the study. Several alterations of the room were carried out, including changes of room dimensions and the type of ceiling absorber, also additional treatment with absorbent material. The effects of these alterations on the decay curves were analysed. In order to predict the gross features of the decay curves, a two-system Statistical Energy Analysis model was developed. The sound field was subdivided into a grazing and nongrazing part. The grazing part comprised modes with propagation direction almost parallel to the 'principal' surface (generally the absorbent ceiling). The nongrazing part comprised the oblique modes, of importance for the decay process. The angle dependent absorbent properties of the principal surface were taken into account when subdividing the sound field into a grazing and nongrazing part. Measured and calculated decay curves for different room configurations were compared.
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| 40. |
- Nilsson, Erling
(author)
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Decay processes in rooms with non-diffuse sound fields Part II: Effect of irregularities
- 2004
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In: Building Acoustics. - : SAGE Publications. - 1351-010X .- 2059-8025. ; 11:2, s. 113-143
-
Journal article (peer-reviewed)abstract
- The effect of sound scattering objects in a rectangular room with high absorption at the ceiling and low absorption at the walls and floor was investigated. In Part I of this paper a two-system Statistical Energy Analysis (SEA) model was developed in order to predict the gross features of the decay process. The sound field is subdivided into a grazing and nongrazing part. The main effect of introducing irregularities is to divert some of the energy in the grazing group into the nongrazing group. The energy transfer between the groups is taken into account by introducing a coupling loss factor. In order to quantify the effect of scattering objects and other irregularities, a measure called equivalent scattering area is introduced. The model demonstrates how the equivalent scattering area can be determined from measurements.
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| 41. |
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| 42. |
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| 43. |
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| 44. |
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| 45. |
- Nilsson, Erling, et al.
(author)
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Trumljud – ett komfortkrav?
- 2004
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In: Bygg & teknik. - 0281-658X. ; :3, s. 20-21
-
Journal article (pop. science, debate, etc.)
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| 46. |
- Nilsson, Erling, et al.
(author)
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Åtgärder mot buller på daghem
- 2003
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In: Bygg & teknik. - 0281-658X. ; :3
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Journal article (pop. science, debate, etc.)
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| 47. |
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| 48. |
- Nilsson, Ingeborg, et al.
(author)
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The Reationship between Engagement in Leisure Activities and Self-Rated Health in Later Life
- 2017
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In: Activities, Adaptation & Aging. - : Taylor & Francis. - 0192-4788 .- 1544-4368. ; 41:2, s. 175-190
-
Journal article (peer-reviewed)abstract
- The aim of this study was to examine leisure engagement among people in later life and the potential relationship between leisure engagement and self-rated health. A population-representative sample of 5,435 persons between 65 and 80 years of age, living in northern Sweden and Finland were included. Data were collected by a posted questionnaire survey. Results revealed that levels of leisure engagement decreased progressively between the youngest and the oldest age groups. A significant relationship was found between leisure engagement and self-rated health. The relationship between leisure engagement and health as well as implications for developing health promotion programs are discussed.
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| 49. |
- Nilsson, Mikael, et al.
(author)
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Fracturing in the footwall at the Kiirunavaara mine, Sweden
- 2014
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Conference paper (peer-reviewed)abstract
- The Kiirunavaara mine is a large scale sub level caving (SLC) mine located near the city of Kiruna in northern Sweden. It is owned and operated by LKAB (Luossavaara-Kiirunavaara AB). The mine produces approximately 28 million tonnes of iron ore annually. Over the last 30 years the mine has experienced a slow but progressive fracturing and movement in the footwall rock mass induced by the SLC operations. The footwall contact which assumes a “slope-like” geometry is partially supported by the caved material from the hangingwall. However, since the late 1980s damage has been observed on the footwall crest as well as within the footwall. Progressive rock mass movement in the footwall is indicated by surface subsidence and visual observations underground. The extent of the damage has traditionally been estimated using empirical relations. Most of the current long term underground infrastructure within the footwall is located at a considerable distance from the ore contact. However, for new developments on deeper levels it is imperative to predict the future extent of the damage volume. Approximating the position of the damage boundary in the footwall at the current state of mining would assist in predicting the extent and characteristics of the damage volume as the mine deepens. LKAB and LTU (Lulea University of Technology) have therefore initiated a joint research project to study the long term stability of the footwall at the Kiirunavaara mine. This paper constitutes part of the work in this research.The paper describes a damage mapping campaign and subsequent analysis of the Kiirunavaara mine footwall to approximate the outer boundary of the damage. The footwall was systematically mapped on 6 levels between 320 and 800 m. The mapping results were then used to interpolate damage lines on the respective levels. The damage lines were used to construct a continuous damage surface between the studied levels. Existing records of damage mapping, monitoring and predictions were reviewed and compared to the results from the current campaign. The new results show that, the outer damage surface appears to remain stationary on the upper levels while new damage was observed on the deeper levels. At levels above 740 m the damage is judged to be mainly controlled by movements along natural discontinuities. At levels below 740 m the majority of the damage seems to be stress induced.
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| 50. |
- Nilsson, Rune, et al.
(author)
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Fractionation of rat IgG subclasses and screening for IgG Fc-binding to bacteria
- 1982
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In: Molecular Immunology. - 1872-9142. ; 19:1, s. 119-126
-
Journal article (peer-reviewed)abstract
- The four IgG subclasses of the rat, IgGl, IgG2a, IgG2b and IgG2c, were purified from normal serum by a combination of protein A-affinity chromatography and DEAE-cellulose chromatography. Purified, radiolabelled preparations of IgG were tested for binding to Gram-positive bacteria representing five different Fc-receptor (FcR) types. Distinct rat subclass-specific Fc-binding was noted to bacterial species belonging to different Fc-receptor types. Staphylococcus aureus (FcR I) strains bind IgGl and IgG2c as shown by others. Group C and G Streptococci (FcR III) bind all four subclasses of rat IgG. Streptococcus zooepidemicus strains (FcR V) also bind all four subclases but only to a lower degree. Human group A Streptococci (FcR II) and bovine group G Streptococci (FcR IV) do not bind any of the rat IgG subclasses. Elution studies on two strains. Staphylococcus aureus, Cowan I, and human group G Streptococcus, G 148, showed that both thiocyanate and pH-elution might be useful for the fractionation of IgG subclasses bound to bacterial cells. The present work indicates the possible use of bacterial cells as solid-phase absorbents in immunological studies of rat IgG.
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