| 1. |
- Johansson, Mairon, 1956-
(författare)
-
I dialogens namn : idén om en överenskommelse mellan regeringen och ideella organisationer
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many European countries have a model of formal agreements between the state and voluntary organisations involved in the core field of welfare, regarding their relative roles and cooperation. This dissertation analyzes the establishment of a Swedish agreement and how the cooperation leads up to the agreement. The cooperation process, known as the dialogue process, took place during more than a year, with the government inviting around eighty voluntary organisations. The theoretical framework of the dissertation is mainly what is know as institutional theory and a line of thought describing how ideas are not transferred and spread but translated and spread. The theoretical focus is on how original ideas are interpreted and why they gain a foothold in new contexts. With the help of empirical material in the form of documents, observations and interviews the dissertation shows how the idea of an agreement was spread from England to Sweden and how the government and the voluntary organisations acted during this process. One of the study’s conclusions is that the voluntary organisations took the initiative to create an agreement about “the role of game” but that the government transformed the voluntary organisations’ idea of an agreement to justify their own political goals. The Swedish agreement can therefore be seen as a step in clarifying Swedish social policy as regards responsibility for welfare. Voluntary organisations that have signed the agreement commit to contribute to securing welfare production. The dissertation shows that this role is appreciated by some of the voluntary organisations, while others question it.
|
|
| 2. |
- Soldati, Pablo, 1978-
(författare)
-
On Cross-Layer Design and Resource Scheduling in Wireless Networks
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wireless technology has revolutionized the world of communications, enabling ubiquitous connectivity and leading every year to several new applications and services embraced by billions of users. To meet the increasing demand for high data-rate wireless services, standardization bodies and vendors released a new generation of standard-based devices capable to offer wide area high-speed and high-quality wireless coverage. More recently, wireless sensor networks (WSNs) have captured the attention of the industry society to migrate substantial parts of the traditionally wired industrial infrastructure to wireless technologies. Despite the increasing appetite for wireless services, the basic physical resource of these systems, the bandwidth, is limited. Therefore, the design of efficient network control mechanisms for optimizing the capabilities of complex networks is becoming an increasingly critical aspect in networking. In this thesis, we explore the application of optimization techniques to resource allocation in wireless systems. We formulate the optimal network operation as the solution to a network utility maximization problem, which highlights how system performance can be improved if the traditionally separated network layers are jointly optimized. The advantage of such cross-layer optimization is twofold: firstly, joint optimization across layers reveals the true performance limits that can be achieved by practical protocols, and is hence useful for network design or performance analysis; secondly, distributed optimization techniques can be used to systematically engineer protocols and signalling schemes that ensure the globally optimal system operation. Within this framework, we consider several challenging problems. The first one considers the design of jointly optimal power and end-to-end rate allocation schemes in multi-hop wireless networks that adhere to the natural time-scales of transport and physical layer mechanisms and impose limited signalling overhead. To validate the theoretical development, we present a detailed implementation of a cross-layer networking stack for DS-CDMA ad-hoc networks in the network simulator ns-2. This implementation exercise reveals several critical issues that arise in practice, but are typically neglected in the theoretical protocol design. Second, we consider networks employing resource scheduling at the data link layer, and we develop detailed distributed solutions for joint end-to-end communication rate selection, multiple time-slot transmission scheduling and power allocation that achieve the optimal network utility. We show with examples how the mathematical framework can be applied to optimize the resource allocation in spatial-reuse time division multiple access (S-TDMA) networks and orthogonal frequency division multiple access (OFDMA) networks. We then make a slight shift in focus, and consider off-line cross-layer optimization to investigate the benefits of various routing strategies in multi-hop networks, and apply these results to a techno-economical feasibility study of cellular relaying networks. Finally, we consider the design of efficient resource scheduling schemes for deadline-constrained real-time traffic in wireless sensor networks. Specifically, we develop theory and algorithms for time- and channel-optimal scheduling of networks operating according to the recent Wireless HART standard.
|
|
| 3. |
- Johansson, Mats P., 1965-
(författare)
-
Reactive Sputtering of Cubic-Phase BN:C and Nanostructured B-N-C Films : Growth, Microstructure, and Mechanical Properties
- 1998
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Synthesis, structure, and mechanical property related issues in the carbon-containing boron nitride (BN:C) system have been studied. Magnetron sputtering, comprising a B4C target in mixed Ar-N2 discharges and deposition parameters of low ion energy, high ion-to-neutral flux ratio, and substrate temperatures <350 °C were employed for growth. Transmission electron microscopy and electron energy loss spectroscopy (EELS) served as the mainstructure evaluation tools, while nanoindentation experiments were used for mechanical property evaluation.Studies of the growth process as a function of partial pressure of nitrogenin the gas mixture revealed first a saturation of the nitrogen on the target whereas at slightly higher PN2 values the overall system is nitrided. This effect was ascribed to the relatively low enthalpy of compound formation of BN. Furthermore, by the use of an internal solenoid coil, the plasma density and hence the ion flux impinging on the growing film could be increased by more than one order of magnitude, resulting in a maximum ion-to-condensing atom flux ratio of ~24. At these conditions, i.e., with a saturation of the nitrogenin corporation frequency on the growth surface and a high flux ratio, growth of cubic-phase c-BN:C was demonstrated at ion-energies as low as 110 eV. This opens a new process window for c-BN phase formation at conditions not accounted for in the prevailing mechanistic models of momentum transfer.The system exhibits a phase evolution sequence of textured (hexagonal)h-BN:C prior to the nucleation and growth of crystallographically oriented cBN:C. The h-BN:C material obtained at intermediate flux-ratios and floating potential exhibits interesting mechanical properties of extreme elasticity and a structure consisting of curved and buckled basal planes similar to what previously have been reported in fullerene-like CNx films. Growth of CNx/BN:C multilayers was demonstrated by sequential sputtering from B4C and graphite targets, respectively, in mixed Ar-N2 atmospheres. They exhibit similar structure as the single-layer films, but do offer additional means for mechanical property design including strengthening over the single-layer compounds.Results are presented to demonstrate the possibility of using sputter deposition technique to synthesize CNx and template-synthesized B-N-C tubular nanostructures, which promises important advances to tailor the structure (dimension and shape) and number density of various types of nanostructures.Finally, an immiscibility between BN and C(N) in magnetron sputtered graphitic layered B-N-C materials was established by EELS. Nitrogen-rich films exhibited predominantly B-N and C-N type of bonds whereas films prepared with a much lower nitrogen concentration also revealed B-C bonds. Thus, magnetron discharge conditions at low temperature is a promising approach to produce B-N, C-N and B-C type of bonds for controlling the chemical composition of nanostructures in the B-N-C ternary system.
|
|
| 4. |
- Sha, Bo, 1987-
(författare)
-
Transport of perfluoroalkyl acids from the ocean to the atmosphere via sea spray aerosol
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Perfluoroalkyl acids (PFAAs) are a subgroup of per- and polyfluoroalkyl substances (PFAS) that have been widely used in commercial and industrial applications. PFAAs are very persistent in the environment and some can bioaccumulate and have adverse health effects on human health. They have been detected ubiquitously in the abiotic environment, in biota and in humans. Long-range atmospheric transport (LRAT) is considered important for their global distribution. PFAAs are detected in the global oceans and they can be enriched in sea spray aerosol (SSA) due to their high surface activity. Thus, ocean-to-atmosphere transfer via sea spray aerosol emission is suggested to be one of the major sources of PFAAs to the atmosphere, yet the contribution of this source to PFAAs in air is not well-understood. The aim of this thesis is to improve the knowledge regarding the importance of SSA as a global source of PFAAs in the atmosphere. In Paper I, PFAA enrichment on SSA particles of different sizes was investigated via a series of laboratory experiments. A sea spray simulation chamber filled with sodium chloride solution (~35 g L-1) was used to generate SSA. The results showed that variation in PFAA water concentrations had little impact on the SSA enrichment factors (EFs). Furthermore, the results suggested that SSA production mechanisms result in different enrichment behaviors of individual PFAAs on <1 µm and >1µm SSA particles. Paper II provided clear field evidence that SSA can be an important source of PFAAs in the atmosphere. Significant positive correlations (p<0.05) were identified between the concentrations of PFAAs and SSA tracer ion (i.e. Na+) in aerosol samples collected at two Norwegian coastal sites during long-term air monitoring. Such correlations suggested that PFAAs transported via SSA can have a significant influence on their air concentrations in coastal areas. Aiming at bridging the gap between the lab and the field, in Paper III, a series of field experiments were conducted along a transect from ~50°N to ~50°S on the Atlantic Ocean. Changes in surface seawater temperature, salinity, conductivity and fluorescence during the field experiments revealed minor influences on EFs. However, the EFs derived from the field experiments were higher than the lab experiments in Paper I, which may be due to the different composition and properties of the chamber water in the two studies. It was concluded, however, that the variation of PFAA concentrations in the global oceans is the major contributor to the uncertainty in the estimation of PFAA ocean-to-air flux via SSA emission. Paper IV investigated mass-size distributions of PFAAs in aerosol samples collected near an industrial source and the associated LRAT potential of the PFAAs emitted. The results suggested that industrial sources can have regional influence on PFAA concentration in air. The information in Paper IV will help evaluate the relative importance of atmospheric sources of PFAAs at certain locations. This thesis contributes to a better understanding on the transport of PFAAs via SSA emission and on the sources of PFAAs to air in general.
|
|
| 5. |
- Törnsén, Monika, 1952-
(författare)
-
Successful Principal Leadership: : Prerequisites, Processes and Outcomes
- 2009
-
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.
|
|
