| 1. |
- Ait Ali, Abderrahman, 1991-
(författare)
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Methods for Capacity Allocation in Deregulated Railway Markets
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Faced with increasing challenges, railways around Europe have recently undergone major reforms aiming to improve the efficiency and competitiveness of the railway sector. New market structures such as vertical separation, deregulation and open access can allow for reduced public expenditures, increased market competition, and more efficient railway systems.However, these structures have introduced new challenges for managing infrastructure and operations. Railway capacity allocation, previously internally performed within monopolistic national companies, are now conferred to an infrastructure manager. The manager is responsible for transparent and efficient allocation of available capacity to the different (often competing) licensed railway undertakings.This thesis aims at developing a number of methods that can help allocate capacity in a deregulated (vertically separated) railway market. It focuses on efficiency in terms of social welfare, and transparency in terms of clarity and fairness. The work is concerned with successive allocation of capacity for publicly controlled and commercial traffic within a segmented railway market.The contributions include cost benefit analysis methods that allow public transport authorities to assess the social welfare of their traffic, and create efficient schedules. The thesis also describes a market-based transparent capacity allocation where infrastructure managers price commercial train paths to solve capacity conflicts with publicly controlled traffic. Additionally, solution methods are developed to help estimate passenger demand, which is a necessary input both for resolving conflicts, and for creating efficient timetables.Future capacity allocation in deregulated markets may include solution methods from this thesis. However, further experimentations are still required to address concerns such as data, legislation and acceptability. Moreover, future works can include prototyping and pilot projects on the proposed solutions, and investigating legal and digitalisation strategies to facilitate the implementation of such solutions.
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| 2. |
- Whitehead, Jake, 1989-
(författare)
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Energy Efficient Vehicle Policy: Lessons Learnt : An analysis of the effects of incentive policies on the demand, usage and pricing of energy efficient vehicles.
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Encouraging the uptake of energy efficient vehicles (EEVs) is an aspiration of critical importance in a day and age in which we are confronted with the increasingly dire consequences of human behaviour on our planet, and on the planet for generations to come. The transport sector is one of the highest contributors of anthropogenic greenhouse gas emissions, whilst pollution from this sector is responsible for a large proportion of human deaths each and every year. Given the severity of these issues, it is more important than ever for policy-makers, and researchers alike, to encourage a transition within the community towards more sustainable lifestyles. Transportation is key to this change.As a service that every human being uses, almost every day of his or her life, the transport sector presents a unique opportunity for behavioural change. Through efficient and targeted policies, consumers can be incentivised to make more sustainable transport choices and to consider the consequences of their own actions. Foremost amongst these initiatives is that of encouraging a transition towards energy efficient vehicles.This thesis has been produced in order to shed further light on issues affecting this transition. In particular for policy-makers, this document includes a series of recommendations based on prevailing findings in the current literature, in addition to the novel and significant findings of this research effort. These include the various lessons learnt from government policies that have already been implemented in regions around the globe.As a thesis by publication, this document consists of four research articles that investigate factors affecting the EEV market, specifically in terms of: consumer demand, vehicle usage and product pricing. A number of other demographic and economic factors have also been examined, including the role of economies-of-scale.
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| 3. |
- Westin, Jonas, 1980-
(författare)
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Efficiency and acceptability of pricing policies and transport investments in distorted economies
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis contains five papers studying the economic efficiency and political acceptability of road pricing policies and transport investments in distorted economies. Interactions between the transport market and other distorted markets, such as the labor market, can have a large impact on the welfare effect of a road pricing policy or a transport investment. Many road pricing studies therefore try to incorporate effects from other distorted markets in the analysis. Paper I analyzes how the economic efficiency of a road toll in a distorted economy depends on assumptions about the initial tax system. In the road pricing literature, the welfare effect of a road toll is often found to depend on revenue use. Using a simple general equilibrium model paper I shows that the relative efficiency of marginal revenue recycling policies depends more on assumptions regarding inefficiencies in the initial tax system than on the road toll per se. Paper II studies the effect on welfare, equity and labor supply from a road toll in a commuting population with heterogeneous value of time and endogenous labor supply. When explicitly taking into account that commuters have different value of time, the road toll can increase total labor supply even when the revenues are not recycled back to the commuters. The analysis stresses the importance of recognizing traveler heterogeneity when analyzing congestion pricing. Road pricing policies are often characterized by conflicting interests between different stakeholders and different geographical areas. Papers III and IV study the economic efficiency and political acceptability of pricing and investment policies in different institutional and geographical settings. The main contribution of the papers is to explain how political constraints can lead to inefficient tolling strategies. The papers contribute to the existing literature on political acceptability of road pricing by analyzing the conflict and potential trade-off between political acceptability and economic efficiency. A difficulty when assessing the welfare effect of a future transport policy is also that many factors and parameters needed for the analysis are uncertain. Paper V studies the climate benefit of an investment in high speed rail by calculating the magnitude of annual traffic emission reduction required to compensate for the annualized embedded emissions from the construction of the line. The paper finds that to be able to balance the annualized emissions from the construction, traffic volumes of more than 10 million annual one-way trips are usually required, and most of the traffic diverted from other transport modes must come from aviation.
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| 4. |
- Ekeberg, Jonas, 1978-
(författare)
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Solitary waves and enhanced incoherent scatter ion lines
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis addresses solitary waves and their significance for auroral particle acceleration, coronal heating and incoherent scatter radar spectra. Solitary waves are formed due to a balance of nonlinear and dispersive effects. There are several nonlinearities present in ideal magnetohydrodynamics (MHD) and dispersion can be introduced by including theHall termin the generalised Ohm’s law. The resulting system of equations comprise the classical ideal MHD waves, whistlers, drift waves and solitarywave solutions. The latter reside in distinct regions of the phase space spanned by the speed and the angle (to the magnetic field) of the propagating wave. Within each region, qualitatively similar solitary structures are found. In the limit of neglected electron intertia, the solitary wave solutions are confined to two regions of slow and fast waves, respectively. The slow (fast) structures are associated with density compressions (rarefactions) and positive (negative) electric potentials. Such negative potentials are shown to accelerate electrons in the auroral region (solar corona) to tens (hundreds) of keV. The positive electric potentials could accelerate solar wind ions to velocities of 300–800 km/s. The structure widths perpendicular to themagnetic field are in the Earth’s magnetosphere (solar corona) of the order of 1–100 km (m). This thesis also addresses a type of incoherent scatter radar spectra, where the ion line exhibits a spectrally uniform power enhancement with the up- and downshifted shoulder and the spectral region in between enhanced simultaneously and equally. The power enhancements are one order of magnitude above the thermal level and are often localised to an altitude range of less than 20 km at or close to the ionospheric F region peak. The observations are well-described by a model of ion-acoustic solitary waves propagating transversely across the radar beam. Two cases of localised ion line enhancements are shown to occur in conjunction with auroral arcs drifting through the radar beam. The arc passages are associated with large gradients in ion temperature, which are shown to generate sufficiently high velocity shears to give rise to growing Kelvin-Helmholtz (K-H) instabilities. The observed ion line enhancements are interpreted in the light of the low-frequency turbulence associated with these instabilities.
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| 5. |
- Hamilton, Carl J.
(författare)
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Implementing Road Pricing : Standards, Institutions, Costs, and Public Acceptance
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Much has been researched and written about road pricing, and especially how it affects traffic flow, congestion, the environment, and social welfare in general. This doctoral thesis analyses the implementation of road user charges rather than its effects. The dissertation consists of five separate papers, each addressing a subset of the topic. The first paper sheds light on the costs to introduce congestion taxes in Stockholm, and describes how public opinion and political risk lead to a system design that in all likelihood was more expensive than necessary. In the second paper the European regulation on interoperability between road charging system is evaluated from a benefit/cost perspective, which is found to be overly ambitious. Paper three builds upon the second, and suggests a general model for how costs and benefits interact in the case of road charging interoperability. Inpaper four a potential solution is presented for how the practical problems related to enforcement of road charging in an international context or in countries with weak institutions. The fifth and final paper analyses the public opinion of road charges, and especially urban congestion charges, using a survey conducted simultaneously in three European cities.
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| 6. |
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| 7. |
- Oldgren, Jonas, 1964-, et al.
(författare)
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Systematic Coronary Risk Evaluation estimated risk and prevalent subclinical atherosclerosis in coronary and carotid arteries: A population-based cohort analysis from the Swedish Cardiopulmonary Bioimage Study
- 2021
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Ingår i: European Journal of Preventive Cardiology. - : Oxford University Press (OUP). - 2047-4873 .- 2047-4881. ; 28:3, s. 250-259
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Tidskriftsartikel (refereegranskat)abstract
- Background It is not clear if the European Systematic Coronary Risk Evaluation algorithm is useful for identifying prevalent subclinical atherosclerosis in a population of apparently healthy individuals. Our aim was to explore the association between the risk estimates from Systematic Coronary Risk Evaluation and prevalent subclinical atherosclerosis. Design The design of this study was as a cross-sectional analysis from a population-based study cohort. Methods From the general population, the Swedish Cardiopulmonary Bioimage Study randomly invited individuals aged 50-64 years and enrolled 13,411 participants mean age 57 (standard deviation 4.3) years; 46% males between November 2013-December 2016. Associations between Systematic Coronary Risk Evaluation risk estimates and coronary artery calcification and plaques in the carotid arteries by using imaging data from a computed tomography of the heart and ultrasonography of the carotid arteries were examined. Results Coronary calcification was present in 39.5% and carotid plaque in 56.0%. In men, coronary artery calcium score >0 ranged from 40.7-65.9% and presence of carotid plaques from 54.5% to 72.8% in the age group 50-54 and 60-65 years, respectively. In women, the corresponding difference was from 17.1-38.9% and from 41.0-58.4%. A doubling of Systematic Coronary Risk Evaluation was associated with an increased probability to have coronary artery calcium score >0 (odds ratio: 2.18 (95% confidence interval 2.07-2.30)) and to have >1 carotid plaques (1.67 (1.61-1.74)). Conclusion Systematic Coronary Risk Evaluation estimated risk is associated with prevalent subclinical atherosclerosis in two major vascular beds in a general population sample without established cardiovascular disease or diabetes mellitus. Thus, the Systematic Coronary Risk Evaluation risk chart may be of use for estimating the risk of subclinical atherosclerosis.
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| 8. |
- Andersson, Matts, 1975-
(författare)
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Policy Analysis for Different Types of Decision-Making Situations
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis seeks to contribute to decision support for policy makers in the transport sector. In order to frame the papers and to relate them to the broad field of “policy analysis”, I have structured the papers around a simple framework with three decision levels: responsibility, policy gap, and policy measure. The thesis contains five papers.“Transaction and transition costs during the deregulation of the Swedish Railway market” is a paper in the transaction cost school. We studied the costs associated with the shift from monopoly to competition in the Swedish railway market, and we found that the change resulted in comparatively small transaction costs, but that transition and misalignment costs seem to be larger. In “Parking policy under strategic interaction”, I examined the effect of strategic interaction between jurisdictions using an analytical model based on Hotelling’s linear city model. I conclude that the procedure for setting supply in most municipalities has a strong downward effect on municipal parking fees and that resource flow competition implies that the fees are higher than the efficient prices (but that the effect of the supply procedures makes this effect incongruous).In “Validation of aggregate reference forecasts for passenger transport”, we followed up the Swedish national forecasts for passenger transport produced from 1975 to 2009 and tried to explain the deviations. We found that the forecasts during the last decades have overestimated car traffic, and that this is due to input errors. The potential problem of using cross-sectional models for forecasting intertemporal changes seems to have been limited.In “The kilometer tax and Swedish industry - effects on sectors and regions”, we estimated factor demand elasticities in the Swedish manufacturing industry and used these to analyze the effects of a kilometer tax for heavy goods vehicles. We found that the kilometer tax leads to factor substitution in that it decreases transport demand and increases labor demand. The effects on output are less pronounced. In “The effect of minimum parking requirements on the housing stock”, we used a model of the rental, asset, and construction markets. We quality-assured our assumptions and our results through interviews with market actors. In our example suburb, we found that parking norms reduced the housing stock by 1.2% and increased rents by 2.4%.
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| 9. |
- Bastian, Anne
(författare)
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Explaining Trends in Car Use
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many western countries have seen a plateau and subsequent decline in car travel during the early 21st century. What has generated particular interest and debate is the claim that the development cannot only be explained by changes in traditional explanatory factors such as GDP, fuel prices and land-use. Instead, it has been argued, the observed trends are indications of substantial changes in lifestyles, preferences and attitudes to car travel and thus, not just a temporary plateau but a true peak in car use.This thesis is a compilation of five papers, studying the issue on a national, international, regional and city scale through quantitative analysis of aggregate administrative data and individual travel survey data. It concludes that the aggregate development of car travel per capita can be explained fairly well with the traditional model variables GDP and fuel price. Furthermore, this thesis shows that spatial context and policy become increasingly important in car use trends: car use diverges over time between city, suburban and rural residents of Sweden and other European countries, while gender and to some extent income become less differentiating for car use.
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| 10. |
- Eliasson, Jonas, 1971-
(författare)
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Ultrasheaves
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis treats ultrasheaves, sheaves on the category of ultrafilters. In the classical theory of ultrapowers, you start with an ultrafilter and, given a structure, you construct the ultrapower of the structure over the ultrafilter. The fundamental result is Los's theorem for ultrapowers giving the connection between what formulas are satisfied in the ultrapower and in the original structure. In this thesis we instead start with the category of ultrafilters (denoted U). On this category U we build the topos of sheaves on U (the ultrasheaves), which we think of as generalized ultrapowers. The theorem for ultrapowers corresponding to Los's theorem is Moerdijk's theorem, first proved by Moerdijk for the topos Sh(F) of sheaves on filters. In the thesis we prove that Los's theorem follows from Moerdijk's theorem. We also investigate the exact relation between the topos of ultrasheaves and Moerdijk's topos Sh(F) and prove that Sh(U) is the double negation subtopos of Sh(F). The connection between ultrapowers and ultrasheaves is investigated in detail. We also prove some model theoretic results for ultrasheaves, for instance we prove that they are saturated models. The Rudin-Keisler ordering is a tool used in set theory to study ultrafilters. It has a strong relationship to the category U. Blass has given a model theoretic characterization of this ordering and in the thesis we give a new proof of his result. One common use of ultrapowers is to give non-standard models. In the thesis we prove that you can model internal set theory (IST) in the ultrasheaves. IST, introduced by Nelson, is a non-standard set theory, an axiomatic approach to non-standard mathematics.
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