| 1. |
- Andéhn, Mikael, 1982-
(författare)
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Place-of-Origin Effects on Brand Equity : Explicating the evaluative pertinence of product categories and association strength
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The country-of-origin effect - the alteration of judgment derived from an association to a place, is a much studied phenomenon with great potential implications for brand management and international marketing. However, in light of criticism towards the lack of conceptual development the extant literature, the relevance of the effect has been brought into question.Through an exploration of the psychology of the association between brands and places, the country-of-origin effect is reimagined focusing on the role of association strength as well as how the interplay between place and product categories can shape consumer attitudes.The results of a series of psychometric tests suggest that association strength and the interplay between place and product category constitute antecedent conditions that are crucial for determining if a country-of-origin effect will occur. These findings, and their implications for future research as well as for practice, suggest that a reevaluation of the country-of-origin effect with a widening of the scope to encompass the commercial relevance of place writ large is warranted.
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| 2. |
- Thomas, Dirk, 1978-
(författare)
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On Rail Vehicle Dynamics in Unsteady Crosswind Conditions : Studies Related to Modelling, Model Validation and Active Suspension
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Crosswind stability of rail vehicles has been a research area for several decades, mainlymotivated by vehicle overturning accidents and higher speeds, but in recent times also byissues of lower energy consumption and track maintenance costs demanding lower vehi-cle weights. During everyday operation, rail vehicles are subjected to substantial lateralinfluences from track curves, track irregularities and crosswind, leading to large suspen-sion deflections and increased crosswind sensitivity. Unsteady crosswind like gusts alsocalls for attention. Simulations of possible vehicle overturning are necessary, but needto take large deflections and high shear in the suspension into account. If they deliverreasonable results, simulations represent an important tool for overturning predictionof rail vehicles.In the present work, multibody simulations of a high-speed rail vehicle under large lat-eral influences from track curves and track irregularities have been carried out, using ahalf-vehicle model in 2D and a full vehicle model in 3D, including different suspensionmodels. Corresponding field measurements of the relative lateral and vertical deflec-tions in the secondary suspension were performed on a fast train and used to validatethe multibody simulations.The 3D vehicle model was further used to study the vehicle response to unsteady cross-wind during curve negotiation, including aerodynamic loads obtained from unsteadyComputational Fluid Dynamics. In addition, the Quasi Transient Gust Modelling methodwas evaluated. Strong lateral and roll responses of the vehicle and influences of the gustduration and the relative difference between mean and maximum wind speed were ob-served. The influence of the vehicle’s suspension and mass properties on crosswindsensitivity were studied in addition.In order to validate modelling and simulation results for gust-like loads on a rail vehi-cle, full-scale experiments were conducted by exciting the carbody of a stationary railvehicle, imitating synchronous and asynchronous crosswind-like loads and measuringthe vehicle response. The measurements were reflected in multibody simulations, whichwere in good agreement with the measured responses. Parameter studies of the suspen-sion characteristics were performed additionally. Asynchronous crosswind-like loadswere in comparison to synchronous loads observed to result in lower wheel-unloadingIt was further studied whether active secondary suspension can be used to improve cross-wind stability. A fast rail vehicle equipped with active secondary suspension for ridecomfort purposes is exposed to crosswind loads during curve negotiation by means ofsimulations. For high crosswind loads, the active suspension is used to reduce the impactof crosswind on the vehicle. The control input is taken from the primary vertical sus-pension deflection. Three different control cases were studied and compared to the onlycomfort-oriented active secondary suspension and a passive secondary suspension. The application of active suspension resulted in significantly improved crosswind stability.
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| 3. |
- Berg, John, 1989-
(författare)
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Den utställda idrotten : idrott som kulturarv på idrottsmuseer i Sverige
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abstract The purpose of this dissertation is to explore the heritagisation of Swedish sports, which is examined through studies of five Swedish sports museums of today. Additionally, the disseration explores the heritagisation of Swedish sports in a wider historical perspective, mainly focusing on the years between 1900 and 2000. There are plenty of sports museums in Sweden today, most of them run by amateurs related to sports history associations. The number of sports museums seem to have increased from the 1980’s, a development that can be seen in relation to a wider interest in heritage, especially heritage produced by amateurs and enthusiasts rather than experts. In the study, this tendency is referred to as “the heritage boom”, a term coined by archeologist Rodney Harrison. Heritage is seen as a both social and material construction which on one hand is determined by language, on the other hand by structural circumstances. When analysing heritage making on sports museums of today, categories such as gender, class, nation and generation have been used. Methodologically, archive studies have been conducted in order to study the heritagisation from a historical perspective, and ethnographic methods such as descriptions and interviews have been used to collect material in sports museums of today. All material have mainly been interpreted through discourse analysis. The results show that the heritagisation of Swedish sports is as old as the organized sports in Sweden, since the first attempts to collect and exhibit the heritage was conducted in the early 1900s. However, despite numerous attempts, the sports heritage have had problems finding ways to be consistent until the very last few decades when the amateur-based heritage production have had its glory days. According to changes within museology and visitor interactment, the future for the Swedish sports heritage is difficult to predict. In the sports museums of today, exhibitions are generally focused on men’s sports, although changes seem to be in the making. Apart from that, there are several differences in how the sports museums constructs generation, class and nation, often depending on how the museums are managed.
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| 4. |
- Berg, Thomas, 1975-
(författare)
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Medical Treatment and Grading of Bell's Palsy
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main aim of this thesis was to evaluate the effect of prednisolone and valaciclovir in a large number of Bell's palsy patients. The incidence and intensity of pain around the ear, in the face or in the neck during the first two months of palsy, and its prognostic value, was also assessed. We also investigated how study design and choice of analysis method affect the rate of facial recovery. Furthermore, the agreement between the Sunnybrook, House-Brackmann and Yanagihara facial grading systems was evaluated. From May 2001 to September 2007, a prospective, randomised, double-blind, placebo-controlled, multicentre trial with 12-month follow-up was performed in patients with Bell's palsy. Of 839 randomised patients, 829 were included in the intention-to-treat analysis; 206 received placebo plus placebo, 210 prednisolone plus placebo, 207 valaciclovir plus placebo, and 206 prednisolone plus valaciclovir. Time to recovery was significantly shorter in the 416 patients who received prednisolone compared with the 413 who did not (p<0.0001). At 12 months, 300 of 416 patients (72%) in the prednisolone group had recovered compared with 237 of 413 patients (57%) in the no prednisolone group (p<0.0001). Valaciclovir was not found to affect time to facial recovery or outcome at 12 months. Prednisolone and/or valaciclovir did not affect the incidence or intensity of pain. Presence of pain at day 11 to 17 indicated a worse prognosis for facial recovery at 12 months. We also found that recovery rates in a Bell's palsy trial are substantially affected by the choice of analysis method and definition of facial recovery. We used weighted Kappa statistics in 100 examinations of patients with facial palsy to assess the agreement between the Sunnybrook, House-Brackmann and Yanagihara scales. The highest agreement was found between the regional Sunnybrook and Yanagihara scales. An evaluative difference between the Sunnybrook and House-Brackmann systems was observed.
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| 5. |
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| 6. |
- Hedfeldt, Mona, 1979-
(författare)
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Företagande kvinnor i bruksort : arbetsliv och vardagsliv i samspel
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Bergslagen region in Sweden has a history of iron and steel production, and in the small industrial towns in the region, one large employer has often held a strong position. Although the region has gone through structural change since the 1970’s, in previous research, becoming self-employed is perceived of as difficult, since it implies going against a strong working culture. The image of Bergslagen is that of a non-entrepreneurial region. Furthermore, in previous research, the gender contract in the region is characterized as traditional. In this thesis light is shed on women in the region who are self-employed. Topics that are focused on are work experience, role models, family situation and networks. The study builds on qualitative interviews and longitudinal registry based statistics (1993-2003). The interviews were carried out in the municipalities of Norberg and Fagersta with self-employed women in the fields of health and business services. Conclusions drawn concern both the region Bergslagen as an entrepreneurial region and the lives of self-employed women. The situations and conditions under which women become and remain self-employed displays a complex interaction between different areas of life, both in relation to the start-up phase and the subsequent running of their businesses. The idea of the region as non-entrepreneurial is scrutinized. For one, the share of self-employed in the Bergslagen municipalities only differs among men, compared to the national average. The share of self-employed women in the region, however, is similar to the national average. Furthermore, the share of self-employed men and women varies among the municipalities within the region. Thus, it is problematic to speak of the region as non-entrepreneurial and as homogenous when it comes to self-employment and entrepreneurship. These findings indicate that the idea of the region as non-entrepreneurial is an expression of both the region being male coded and women entrepreneurs being subordinated.
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| 7. |
- Karis, Tomas, 1985-
(författare)
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Correlation between Track Irregularities and Vehicle Dynamic Response Based on Measurements and Simulations
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Deviations from the design track geometry are called track irregularities, which are a main excitation mechanism in the track–vehicle dynamic system, and very important to monitor and maintain to have trac on a line run safely and comfortably. Especially during vehicle acceptance testing, it is important that a new vehicle behaves close to design predictions and within limit values, thus it is important to be able to describe track irregularities in a consistent way.There are several methods which quantify the eects track irregularities have on a vehicle while running along the track. Most common is analyse standard deviations and percentiles and maximum values over sections with pre-defined length. However, these quantities do not correlate well with the vehicle dynamic response, e.g. two track sections with similar maxima and standard deviations can result in very dierent response of the vehicle.To improve the correlation between track irregularities and vehicle re- sponse measures, it is recommended by past research to use multiple regres- sion analysis to take e.g. vehicle speed and track curvature into account as well. Other methods range from derivatives of track irregularities, via trans- fer functions and vehicle filters to neural networks. Common for all these methods are that there is either still slight inconsistencies in the results or that they are tailored for certain vehicle types on specific lines. As a result, the preferred method to evaluate track irregularities is still to use standard deviations.In this thesis, data from three vehicles in two measurement campaigns is evaluated using a single degree of freedom model as inspiration to break down the path from track to vehicle into several steps. A weak link in these steps is identified, which shows significantly lower correlation coecients than the other steps. The weak link is the step from vertical track irregularity second spatial derivative to vertical axle box acceleration divided by the squared vehicle speed. A variable wavelength range Dx is introduced, as an alternative to the common D1 (3–25 m), D2 (25–70 m) and D3 (70–150 m) wavelength ranges. Its wavelength range corresponds to the vehicle response band-pass filter frequencies and is thus speed dependent.Simulations are also carried out to investigate the weak link and for the possibility to vary parameters that cannot be changed during on-track mea- surements. A multi-body system model of the passenger coach Bim 547.5 is used, together with recorded track data and vehicle speed from the on-track measurements. The varied parameters have rather low sensitivity and aect results to a small extent. Most impact has the randomly varying vertical track stiness which aects the vertical wheel–rail forces and axle box accelerations.In future work, it should be explored if it is possible – and in such case how – to separate the eects of varying track stiness from the track irreg- ularities. This to better understand when a vehicle response is linked more to the track irregularities or to the track flexibility. The weak link identified in the steps from track to vehicle should also be further explored, perhaps by extending the underlying model or evaluate a dierent set of measurements.
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| 8. |
- Krishna, Visakh V
(författare)
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Long freight trains and long-term rail surface damage
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Track damage due to progressively increasing tonnage, especially due to longer and heavier freight trains, is one of the major problems faced in the European rail sector. In this context, to stay competitive, optimal track maintenance practices, track-friendly vehicles and safe operations of long freight trains assume prominence.This PhD thesis studies long freight train operations and the long-term rail surface damage that they cause, to build a computer simulation-based framework for maintenance planning and assessment of running safety. The framework is formulated with four parts: long freight train operations, vehicle dynamics, rail surface damage and track maintenance. This is followed by a literature survey on each of the subtopics and how they are linked to each other.Safe operation of long freight trains in infrastructure bottlenecks such as S-curves is studied using three-dimensional multi-body simulations. Based on this, guidelines to build long freight trains and driving scenarios that can keep longitudinal in-train forces within acceptable limits have been provided. Multi-body simulation models of various freight bogies, including a novel design, are built and their dynamic running behaviour studied according to EN standards. The key focus is on track-loading and to this effect, methodologies for simulations-based assessment of `track-friendliness' of various bogie designs are studied. Various approaches to quantify rail surface damage using multi-body simulations in the form of wear and Rolling Contact Fatigue (RCF) are studied. Based on this, measures to ascertain similarities and differences in results from different approaches have been put forward. The impact of track maintenance, in the form of periodic rail reprofiling activities in different networks, on the evolution of rail surface damage is studied. It is found that optimal maintenance planning can be tailored depending on the type of traffic on the network.Finally, various parts of the framework have been brought together to form a `train-track interaction' approach to facilitate optimal maintenance planning.
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| 9. |
- Persson, Rickard, 1958-
(författare)
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Tilting trains : Enhanced benefits and strategies for less motion sickness
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Carbody tilting is today a mature and inexpensive technology that allows higher train speeds in horizontal curves, thus shortening travel time. This doctoral thesis considers several subjects important for improving the competitiveness of tilting trains compared to non-tilting ones. A technology review is provided as an introduction to tilting trains and the thesis then focuses on enhancing the benefits and strategies for less motion sickness. A tilting train may run about 15% faster in curves than a non-tilting one but the corresponding simulated running time benefit on two Swedish lines is about 10%. The main reason for the difference is that speeds are set on other grounds than cant deficiency at straight track, stations, bridges, etc. The possibility to further enhance tilting trains’ running speed is studied under identified speed limitations due to vehicle-track interaction such as crosswind requirements at high speed curving. About 9% running time may be gained on the Stockholm–Gothenburg (457 km) mainline in Sweden if cant deficiency, top speed, and tractive performance are improved compared with existing tilting trains. Non-tilting high-speed trains are not an option on this line due to the large number of 1,000 m curves. Tilting trains run a greater risk of causing motion sickness than non-tilting trains. Roll velocity and vertical acceleration are the two motion components that show the largest increase, but the amplitudes are lower than those used in laboratory tests that caused motion sickness. Scientists have tried to find models that can describe motion sickness based on one or more motion quantities. The vertical acceleration model shows the highest correlation to motion sickness on trains with active tilt. However, vertical acceleration has a strong correlation to several other motions, which precludes vertical acceleration being pointed out as the principal cause of motion sickness in tilting trains. Further enhanced speeds tend to increase carbody motions even more, which may result in a higher risk of motion sickness. However, means to counteract the increased risk of motion sickness are identified in the present work that can be combined for best effect. Improved tilt control can prevent unnecessary fluctuations in motion sickness related quantities perceived by the passengers. The improved tilt control can also manage the new proposed tilt algorithms for less risk of motion sickness, which constitute one of the main achievements in the present study. Local speed restrictions are another means of avoiding increased peak levels of motion sickness when increasing the overall speed. The improved tilt control and the proposed tilt algorithms have proven to be effective in on-track tests involving more than 100 test subjects. The new tilt algorithms gave carbody motions closer to non-tilting trains. Rather unexpectedly, however, the test case with the largest decrease in tilt gave a greater risk of motion sickness than the two test cases with less reduction in tilt. It is likely that even better results can be achieved by further optimization of the tilt algorithms; the non-linear relation between motions and motion sickness is of particular interest for further study.
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| 10. |
- Berg, Johan, 1967-
(författare)
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Gods och landskap : Jordägande, bebyggelse och samhälle i Östergötland 1000-1562
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study examines landownership structures and settlement during the Middle Ages in the province of Östergötland in Sweden. It departs from a critical approach to the established view of social structure and property in the Scandinavian medieval society.The investigations are made at two levels. The first level is a cross section of the mid 16th century. This investigation shows that lay aristocrats and ecclesiastical institutions controlled most of the land, especially in the core areas of the parishes. The second level is a detailed investigation at the farm level in six parishes starting from the middle of the 16th century and working retrogresively to the early Middle Ages. This study shows that the landowning structure of the 16th century can be traced back to about AD 1300. For the early Middle Ages reconstructions are made through inheritance successions and genealogies of the aristocratic families. These reconstructions show that, in some parishes, most of the land was probably controlled by a few very rich families or dynasties during the early Middle Ages. The results lead to a question about the Viking Age and medieval society in general. This question is answered in a hypothesis stressing the development of the concept of land ownership in combination with the development of the land tenure system as one of the important factors for reproduction of local power during the Viking Age and early Middle Ages.
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