| 1. |
- Averfalk, Helge, 1988-
(författare)
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Enhanced District Heating Technology : Maintaining Future System Feasibility
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When heat demand and high temperature heat supply gradually decreases in the future, then it will effect district heating systems ability to compete on the heat market. A good way to mitigate less district heating feasibility is to operate systems with lower temperature levels and the most conceivable way to achieve lower temperature levels is to decrease return temperatures.Thus, this thesis emphasise temperature errors embedded in district heating systems. Only a selection of temperature errors are analysed in this thesis. First, the temperature error that occurs due to recirculation in distribution networks at low heat demands. Second, the temperature error that occurs due to hot water circulation in multi-family buildings. Third, the temperature error that occurs due to less than possible heat transfer in heat exchangers, i.e. too short thermal lengths.In order to address these temperature errors three technology changes have been proposed (i) three-pipe distribution network to separate the recirculation return flow from the delivery return flow, (ii) apartment substations to eliminate hot water circulation utilisation, and (iii) improved heat exchangers for lower return temperatures at a constant scenario. Analysis of proposed changes has resulted in annual average return temperatures between 17-21 °C.Furthermore, rapid introduction of intermittent renewable electricity supply in the energy system has prompted an increased necessity of power system balancing capacities. Large-scale conversion of power-to-heat in electric boilers and heat pumps is a feasible alternative to achieve such balancing capacities. Analysis of the unique Swedish experience with utilisation of large heat pumps installations connected to district heating systems show that since the 1980s 1527 MW of heat power has been installed, about 80 % of the capacity was still in use by 2013. Thus, a cumulative value of over three decades of operation and maintenance exists within Swedish district heating systems.The two papers presented in this thesis are related to future district heating systems through the five abilities of fourth generation district heating (4GDH), which are documented in the definition paper of 4GDH.
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| 2. |
- Brännström, Inger, 1945-
(författare)
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Community participation and social patterning in cardiovascular disease intervention
- 1993
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study addresses health policy and public health in the field of cardiovascular disease (CVD) on the local level in Sweden. The overall aim is to contribute to the assessment of structural and social conditions within public health by analysing participation processes and outcome patterns in a local health programme. The northern Swedish MONICA study served as a reference area. The research strategy has been to integrate quantitative and qualitative methodologies and, thereby, focus on different aspects of the health programme under study.The mortality rate was excessive in the study area of Norsjö relative to both provincial and national figures over a period of more than 10 years. This finding formed the basis for a tenyear comprehensive and community-based health programme towards the prevention of CVD and diabetes.Even in this seemingly homogeneous area it was found that socio-economic circumstances were associated with the public health. Almost half of the study population had hypercholesterolaemia (;>6.5 mmol/1), 19% of men and 25% of women were smokers and 30% and 29%, respectively, had high blood pressure. Age had a strong impact on all outcome measures. After adjustments for age and social factors it was found that the relative risk of having hypercholesterolaemia dropped significantly in both sexes during the six years of intervention. The probability of being a smoker was significantly reduced only in highly educated groups. No statistically significant change over time could be found for the risk of suffering high blood pressure. In the reference area of northern Sweden there were no changes over time for any of the selected risk factors. The likelihood of self-assessed good health decreased with increasing risk factor load, with the exception of hypercholesterolaemia , in all social strata.The authorities, including the health and medical staff, were the main actors on the mediastage. Men in manual occupations were least affected by the media coverage. The actors and the public as well as the media viewed the health programme as orientated towards individual lifestyles. Community participation was mainly defined by the actors based on the medical and health planning approach. Differences in interpretations, social interests, personal conflicts and ideological constraints among the actors at local level were observed. Some critical attitudes towards the organization and management of the health programme were also noted among the citizens. However, a majority of the public wanted the health programme to continue. The present study underlines the importance of considering age, gender and social differences in the planning and evaluation of CVD preventive programmes.
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| 3. |
- Dzansi, James
(författare)
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Essays on Financing and Returns on Investment
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation consists of an introductory chapter and three independent essays on financing investment and their returns. The first essay studies the impact of remittances on domestic investment. The analysis is carried out with a focus on the moderating roles of domestic financial development and institutional quality. The empirical results suggest that remittance inflows are associated with increased domestic investment spending, particularly under conditions of inadequate financial intermediation and poor institutional quality. The second essay evaluates whether remittance inflows into the developing world impedes or spurs manufacturing growth. This study uses manufacturing data on a sample of 40 remittance dependent economies over the period from 1991 to 2004. The results suggest that remittance inflows accelerate manufacturing growth. This evidence is robust to industry- and year-specific effects, a range of country level control variables, and a number of estimators. The final essay examines the monitoring role of large shareholders and returns on investment. Specifically, the paper investigates the relevance of intrinsic motives of the large shareholder to monitor management in order to induce optimal return on investment. The findings suggest that large shareholders are actuated by both intrinsic and extrinsic motives to minimize managerial opportunism and inefficiency.
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| 4. |
- Reitsma, Ewout
(författare)
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Sourcing strategising in the new product development process : Insights from the strategy-as-practice lens and engineer-to-order context
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In many cases, manufacturers have changed from sourcing only a few, simple, and separate components from local suppliers to sourcing a high variety of modules from globally dispersed suppliers. This has resulted in the implementation of a wide variety of sourcing strategies, including, for example, multiple sourcing and supplier integration. All these and other sourcing strategies are aimed at achieving a certain level of supply chain (SC) responsiveness. The level of SC responsiveness ideally matches the characteristics of a product. For example, highly innovative products typically require highly responsive SCs.In order to match products with their SCs, manufacturers are advised to engage in sourcing strategy in their new product development (NPD) process. However, there are at least two knowledge gaps in the literature on this topic: (1) the lack of a widely accepted, comprehensive conceptualisation of how manufacturers can engage in sourcing strategy in NPD, and (2) the lack of empirical insights into manufacturers operating in the engineer-to-order (ETO) context. This dissertation focuses on filling these knowledge gaps.Addressing the first gap, the dissertation uses the theoretical lens of ‘strategy-as-practice’ (SAP) and the literature to conceptualise the ‘doing of sourcing strategy’ in NPD as three interrelated dimensions: (1) practitioners, (2) activities, and (3) practices. Through discussing these dimensions and their potential interplay throughout NPD, the dissertation demonstrates the potential of the SAP lens in providing a common framework and reducing the fragmented nature of the literature. By using the SAP lens, the dissertation also contributes to practice. Despite not being ‘actionable’ in the sense of constituting detailed guidelines for acting, the SAP lens produces insights that can help practitioners to become more reflective. For example, they can learn to see sourcing strategising as a multidimensional, dynamic concept and the place it can occupy in the NPD process.The second knowledge gap in the literature regards the lack of empirical research focusing on the ETO context. Therefore, the dissertation includes a case study focusing on practitioners’ sourcing strategising activities and practices in this context. First, five approaches to performing sourcing strategising activities in NPD are explored in terms of their conditions and intended outcomes. Secondly, four practices that can support sourcing strategising in NPD are identified. These practices – referred to as ‘Design for Supply Chain’ (DFSC) practices – are also examined in terms of their interrelations. Practitioners can use the case study findings to compare the advantages of the five sourcing strategising approaches when sourcing items or services. Furthermore, the findings allow practitioners to assess how the four interrelated DFSC practices can support their sourcing strategising efforts in NPD.
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| 5. |
- Höglund, Linda, 1974-
(författare)
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Growth and characterisation of InGaAs-based quantum dots-in-a-well infrared photodetectors
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents results from the development of quantum dot (QD) based infrared photodetectors (IPs). The studies include epitaxial growth of QDs, investigations of the structural, optical and electronic properties of QD-based material as well as characterisation of the resulting components.Metal-organic vapour phase epitaxy is used for growth of self-assembled indium arsenide (InAs) QDs on gallium arsenide (GaAs) substrates. Through characterisation by atomic force microscopy, the correlation between size distribution and density of quantum dots and different growth parameters, such as temperature, InAs deposition time and V/III-ratio (ratio between group V and group III species) is achieved. The V/III-ratio is identified as the most important parameter in finding the right growth conditions for QDs. A route towards optimisation of the dot size distribution through successive variations of the growth parameters is presented.The QD layers are inserted in In0.15Ga0.85As/GaAs quantum wells (QWs), forming so-called dots-in-a-well (DWELL) structures. These structures are used to fabricate IPs, primarily for detection in the long wavelength infrared region (LWIR, 8-14 μm).The electron energy level schemes of the DWELL structures are revealed by a combination of different experimental techniques. From Fourier transform photoluminescence (FTPL) and FTPL excitation (FTPLE) measurements the energy level schemes of the DWELL structures are deduced. Additional information on the energy level schemes is obtained from tunneling capacitance measurements and the polarization dependence studies of the interband transitions. From tunneling capacitance measurements, the QD electron energy level separation is confirmed to be 40-50 meV and from the polarization dependence measurements, the heavy hole character of the upper hole states are revealed.Further characterisation of the IPs, by interband and intersubband photocurrent measurements as well as dark current measurements, is performed. By comparing the deduced energy level scheme of the DWELL structure and the results of the intersubband photocurrent measurements, the origin of the photocurrent is determined. The main intersubband transition contributing to the photocurrent is identified as the QD ground state to a QW excited state transition. Optical pumping is employed to gain information on the origin of an additional photocurrent peak observed only at temperatures below 60 K. By pumping resonantly with transitions associated with certain quantum dot energy levels, this photocurrent peak is identified as an intersubband transition emanating from the quantum dot excited state. Furthermore, the detector response is increased by a factor of 10, when using simultaneous optical pumping into the quantum dots states, due to the increasing electron population created by the pumping. In this way, the potentially achievable responsivity of the detector is predicted to be 250 mA/W.Significant variations of photocurrent and dark currents are observed, when bias and temperature are used as variable parameters. The strong bias and temperature dependence of the photocurrent is attributed to the escape route from the final state in the QW, which is limited by tunneling through the triangular barrier. Also the significant bias and temperature dependence of the dark current could be explained in terms of the strong variation of the escape probability from different energy states in the DWELL structure, as revealed by interband photocurrent measurements. These results are important for the future optimisation of the DWELL IP.Tuning of the detection wavelength within the LWIR region is achieved by means of a varying bias across the DWELL structure. By positioning the InAs quantum dot layer asymmetrically in a 8 nm wide In0.15Ga0.85As/GaAs quantum well, a step-wise shift in the detection wavelength from 8.4 to 10.3 μm could be achieved by varying the magnitude and polarity of the applied bias. These tuning properties could be essential for applications such as odulators and dual-colour infrared detection.
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| 6. |
- Johansson, Stefan, 1963-
(författare)
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Design for Participation and Inclusion will Follow : Disabled People and the Digital Society
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Digitalization is rapidly taking over all aspects of society, but still there are parts of the population who have to struggle for access to, and to be able to use, the digital resources. Design processes and outcomes in the form of artefacts, that takes accessibility into account, is key to participation. This gives the designer a central role in providing for a more equal participation of all, in the digital society. The work in this thesis contributes to a better understanding of the prerequisites for participation in the digital society, and in the design processes to accomplish this, by presenting research done together with three communities: people with cognitive impairments, people with mental health issues and homeless people.The overall question has been How can participation in the digital society be understood? We have investigated the nature of difficulties or enabling factors for people with impairments, people with mental health issues and homeless people, when using the internet. We have also investigated possible digital divides within the groups, and how they can be explained.Ontologically, the work is based on an assumption that knowledge is to be found in a dialectic interplay between the material world and how we interpret what is going on in this world. The underlying epistemological assumption is that data has to be empiric, and critically interpreted in dialogue between members of the communities, which are being researched, and other stakeholders. This work draws on the idea of emancipation and that research can be liberating.The work also takes on a pragmatic stance. We have used adapted versions of Emancipatory Participatory Research, and of Participatory and Value Sensitive Design, thus making them accessible to people with cognitive impairments, people with mental health issues or homeless people. We have tested and adapted methods for sampling of rare populations, to enhance the quality of quantitative studies of how people with impairments and people with mental health issues have access to, and are using, the internet.In our research, we have found fourteen prerequisites, all of which need to be in place to provide for participation. To promote participation, we need a toolbox of methods and accessible tools. Finally, to analyse what is going on we need an analytical model which allows for analysis on multiple levels and from multiple perspectives.As a result, I here propose, define and position a framework for researching and understanding participation in the digital society, based on three parts: Guidelines, Ethics and Statistics. Guidelines can be understood as the theories, the regulations, the standards, etc. that inform our thinking. Ethics guide us in the right direction. Statistics make progress or lack of progress visible.The conclusion is: if we plan for participation - by improved statistic survey sampling methods, a participatory approach to collaborative research and in using research methods in an accessible and emancipatory way – inclusion will follow.
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| 7. |
- Mohammadi, Mohammad
(författare)
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Probabilistic time estimation in tunnel projects
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Transport infrastructure projects, including tunneling, suffer from timedelays and cost overrun. A literature review shows that the effect ofuncertainty has been neglected in explaining time and cost overrunmeaning that technical explanations matter. Probabilistic estimations oftime and cost can be employed for dealing with uncertainty in transportinfrastructure projects.In this licentiate thesis, KTH’s probabilistic time and cost estimationmodel for tunneling projects (Isaksson and Stille, 2005, Rock Mech. RockEng., 38, 373-398) was improved. The improvements include breakingdown the production activities into their sub-activities, which form thebasis for assessing times (or costs) for tunnel construction. In addition, theexceptional time and the length of model’s geotechnical zones aredescribed as stochastic variables instead of deterministic values used in theoriginal model. Given its hierarchical structure, the model can be used fortime and cost estimation of all types of tunnels and all constructionmethods in various geological condition.The improved version of the model uses three types of input parametersthat are probabilities of occurrences of different geological condition andidentified undesirable events, production effort of sub-activities (i.e. timespent for performing the sub-activity per unit length of tunnel) andadditive delay time that is imposed as a result of occurrence of undesirableevents. The important issues in modeling the uncertainty in the productionefforts of sub-activities are also explained.
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| 8. |
- Törnsén, Monika, 1952-
(författare)
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Successful Principal Leadership: : Prerequisites, Processes and Outcomes
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis' main theme is successful principal leadership in secondary schools within the Swedish education system. Successful principal leadership is examined from three perspectives: What are the processes of a successful principal? Do the leadership processes relate to successful academic and social outcomes of schools? What are the prerequisites for successful principal leadership? The Frame Factor Model and the three concepts of prerequisites, processes and outcomes constitute an overarching framework. The prerequisites are categorized as internal prerequisites (the particular characteristics of individual principals) and external prerequisites operating within the Swedish educational environment. The successful principal processes are viewed as pedagogical leadership processes, on one hand as providing prerequisites for teaching and learning and, on the other hand as leading the core processes of teaching and learning. The definitions build on the empirical data, on the Swedish national curriculum and demands for pedagogical leadership, and on international findings on what successful principals do. The outcomes of successful principal leadership are here defined as the academic and the social outcomes of schools. The research undertaken is part of the research project 'Structure, Culture, Leadership - Prerequisites for Successful Schools?' The empirical data for this thesis are gathered in twenty-six Swedish secondary schools whereof five are regarded successful schools based on both academic and social outcomes. The findings, reported on in four articles, derive from interviews and questionnaires to principals and teachers. The principals in the main identify prerequisites of importance that are within their own realm of influence, such as themselves, teachers and school district level. They consider a limited area of responsibility and support from district level specialists as providing possibilities for their success. The principals accept the national governance of schools and principals via the national curriculum. The principals in the five successful schools however take a higher degree of responsibility for setting direction towards national goals, for processes inside schools and for school outcomes than do principals in less successful schools.They as pedagogical leaders attend to a higher degree both to providing prerequisites for teaching and learning and to leading the core processes of teaching and learning than do principals in less successful schools. In schools with a successful implementation of social goals, which shows as successful social outcomes, the principals, according to teachers, overall take responsibility for their national objectives and obligations to a higher degree than principals in schools with a less successful implementation of social goals. The implementation of social goals is of importance not only from an outcome perspective but also from a process perspective. It requires collaborative interpretation which can promote principal-staff professional relations and ultimately student learning. The identified overall differences between principals' leadership processes and processes in the twenty-six schools raise questions around consequences for equivalence in education.
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| 9. |
- Andersson, Hanna, 1991-
(författare)
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Tradeoffs between self and environment in environmental judgment and decision making
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the greatest challenges of today is to change our behavior to act more pro-environmentally to reduce global warming. We need to make sacrifices for the environment, e.g., use a means of transportation that take a longer time but causes less CO2 emission. The present thesis aims to study different factors (intrinsic, extrinsic motivational, and extrinsic motivational-neutral information) that influence us when making tradeoffs between self and environment. Paper I examined how an anchor (a reference price) and an ecolabel influence price judgments. It was found that both a judgment of an objective fact (product price) and a subjective preference (willingness to pay for the product) were affected by an anchor. An eco-label resulted in higher judgments of objective facts. People with higher environmental concern were more affected by an anchor when stating their willingness to pay than their low concern counterparts. In Paper II and Paper III, an interaction between a high anchor and a normative message that put the emissions into context was found when making a tradeoff between CO2 emissions and travel time for a flight (Paper II) or a car journey (Paper III). People with higher concern for the environment gave a longer travel time when they received a high anchor (Paper II and Paper III) or no anchor (Paper III). Paper IV investigated how a survey measuring environmental concern can be divided to different indices and how they predict answers in a tradeoff task. The result suggests that a two-factor structure divided into ecocentric and anthropocentric concern is a possible alternative and that people scoring higher on any of the environmental concern indices were willing to travel for a longer time. Taken together, the results show that normative messages, anchors, and concern for the environment are factors that can influence and interact when people make tradeoffs between self and environment in environmental judgment and decision making.
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| 10. |
- Andersson K, Pernille
(författare)
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Changing the servicescape : The influence of music, self-disclosure and eye gaze on service encounter experience and approach-avoidance behavior
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis is to investigate and understand the effect of a servicescape’s ambient and social conditions on consumers’ service encounter experience and their approach/avoidance behavior in a retail context. In three papers, with a total sample of over 1600 participants (including 550 actual consumers) and seven experiments, the author investigates the effect of music (ambient stimuli), employees’ self-disclosure (verbal social stimuli) and employees’ gazing behavior (nonverbal social stimuli) on consumers’ service encounter experience and approach/avoidance behavior in a retail store.Paper I comprised two experiments, and the aim was to investigate the influence of music on emotions, approach/avoidance behavior. Paper II comprised two experiments, and the aim was to investigate the effect of frontline employees’ personal self-disclosure on consumers’ reciprocal behavior. Paper III comprised three experiments, and the aim was to investigate the influence of employee’s direct eye gaze/ averted eye gaze on consumer emotions, social impression of the frontline employee and encounter satisfaction in different purchase situations.The results in this thesis show that music affects consumers in both positive and negative ways (Paper I). Self-disclosure affects consumers negatively, in such a way that it decreases encounter satisfaction (Paper II) and, finally, eye gaze affects consumers by regulating both positively – and in some cases also negatively – consumers’ social impression of the frontline employee and their encounter satisfaction (Paper III).The conclusions of this thesis are that both ambient and social stimuli in a servicescape affect consumers’ internal responses, which in turn affect their behavior. Depending on the purchase situation, type of retail, and stimuli, the internal and behavioral responses are different.
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