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  • Public defence: 2017-12-15 14:15 Homeros, Växjö
    Vogt, Bettina
    Linnaeus University, Faculty of Social Sciences, Department of Education.
    Just assessment in school: - a context-sensitive comparative study of pupils' conceptions in Sweden and Germany2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis examines pupils’ justice conceptions regarding educational assessment. Due to the context-dependency of norms and values as well as of assessment, the study compares the justice conceptions of pupils in two different’socio-educational’ contexts: Sweden and Germany. The main interest of the study is to understand and to reconstruct pupils’ own relevance structures and what just assessment means from a pupils’ point of view. Here, the study aims to reach beyond the level of mere description by providing theoretical conceptualisations of pupils’ justice conceptions regarding assessment. Thus, the study´s methodological foundation is characterised by a combination of a context-sensitive comparative approach on the one hand, and on the other hand a pragmatist Grounded Theory approach. Data were mainly generated through focus group interviews with pupils attending the last year of the lower secondary level in the Swedish comprehensive school as well as in different school types in the German school system. In total, the sample consists of 95 pupils, who were interviewed in 21 focus group interviews. In addition, other sources of data were included, such as regulations and guidelines that supported a context-sensitive analysis of pupils’ conceptions. The theoretical conceptualisation that explains pupils’ justice conceptions is ‘meta-assessment’. ‘Meta-assessment’ refers to pupils’ evaluation of the assessment they experience in terms of justice and represents the shared, abductively derived and overlying analytical category regarding pupils’ conceptions. Pupils’ ‘meta-assessment’ is based on normative justice conceptions as well as on justice conceptions that are related to pupils’ situation and context-bound experiences with assessment. The first ones are about the ethico-moral character of pupils’ justice conceptions. The second shed light on the contextual conditions and consequences of the logics and practices underlying educational assessment as experienced by pupils on an everyday basis. This implies that just assessment from a pupils’ perspective needs to be understood in its wider contextual embedment; and in relation to teaching and learning in order to understand the complex interrelations of what just assessment ‘is’, and ‘should be’ from the perspective of those, who are mainly affected by it.

  • Public defence: 2017-12-18 13:15 C1202 (Newton), Växjö
    Iftikhar, Muhammad Usman
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics. Faculty of Engineering Science, Department of Computer Science, KU Leuven, Belgium.
    A Model-Based Approach to Engineer Self-Adaptive Systems with Guarantees2017Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Modern software systems are increasingly characterized by uncertainties in the operating context and user requirements. These uncertainties are difficult to predict at design time. Achieving the quality goals of such systems depends on the ability of the software to deal with these uncertainties at runtime. A self-adaptive system employs a feedback loop to continuously monitor and adapt itself to achieve particular quality goals (i.e., adaptation goals) regardless of uncertainties. Current research applies formal techniques to provide guarantees for adaptation goals, typically using exhaustive verification techniques. Although these techniques offer strong guarantees for the goals, they suffer from well-known state explosion problem. In this thesis, we take a broader perspective and focus on two types of guarantees: (1) functional correctness of the feedback loop, and (2) guaranteeing the adaptation goals in an efficient manner. To that end, we present ActivFORMS (Active FORmal Models for Self-adaptation), a formally founded model-driven approach for engineering self-adaptive systems with guarantees. ActivFORMS achieves functional correctness by direct execution of formally verified models of the feedback loop using a reusable virtual machine. To efficiently provide guarantees for the adaptation goals with a required level of confidence, ActivFORMS applies statistical model checking at runtime. ActivFORMS supports on the fly changes of adaptation goals and updates of the verified feedback loop models that meet the changed goals. To demonstrate the applicability and effectiveness of the approach, we applied ActivFORMS in several domains: warehouse transportation, oceanic surveillance, tele assistance, and IoT building security monitoring.

  • Public defence: 2017-12-20 10:15 C1202 (Newton), Växjö
    Gustafsson, Alexander
    Linnaeus University, Faculty of Technology, Department of Physics and Electrical Engineering.
    Theoretical modeling of scanning tunneling microscopy2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The main body of this thesis describes how to calculate scanning tunneling microscopy (STM) images from first-principles methods. The theory is based on localized orbital density functional theory (DFT), whose limitations for large-vacuum STM models are resolved by propagating localized-basis wave functions close to the surface into the vacuum region in real space. A finite difference approximation is used to define the vacuum Hamiltonian, from which accurate vacuum wave functions are calculated using equations based on standard single-particle Green’s function techniques, and ultimately used to compute the conductance. By averaging over the lateral reciprocal space, the theory is compared to a series of high-quality experiments in the low- bias limit, concerning copper surfaces with adsorbed carbon monoxide (CO) species and adsorbate atoms, scanned by pure and CO-functionalized copper tips. The theory compares well to the experiments, and allows for further insights into the elastic tunneling regime.

    A second significant project in this thesis concerns first-principles calculations of a simple chemical reaction of a hydroxyl (oxygen-deuterium) monomer adsorbed on a copper surface. The reaction mechanism is provided by tunneling electrons that, via a finite electron-vibration coupling, trigger the deuterium atom to flip between two nearly identical configurational states along a frustrated rotational motion. The theory suggests that the reaction primarily occurs via nuclear tunneling for the deuterium atom through the estimated reaction barrier, and that over-barrier ladder climbing processes are unlikely. 

  • Public defence: 2018-01-12 09:30 Fullriggaren, Kalmar
    Bunse, Carina
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bacterioplankton in the light of seasonality and environmental drivers2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Bacterioplankton are keystone organisms in marine ecosystems. They are important for element cycles, by transforming dissolved organic carbon and other nutrients. Bacterioplankton community composition and productivity rates change in surface waters over spatial and temporal scales. Yet, many underlying biological processes determining when, why and how bacterioplankton react to changes in environmental conditions are poorly understood. Here, I used experiments with model bacteria and natural assemblages as well as field studies to determine molecular, physiological and ecological responses allowing marine bacteria to adapt to their environment.

    Experiments with the flavobacterium Dokdonia sp. MED134 aimed to determine how the metabolism of bacteria is influenced by light and different organic matter. Under light exposure, Dokdonia sp. MED134 expressed proteorhodopsin and adjusted its metabolism to use resources more efficiently when growing with lower-quality organic matter. Similar expression patterns were found in oceanic datasets, implying a global importance of photoheterotrophic metabolisms for the ecology of bacterioplankton.

    Further, I investigated how the composition and physiology of bacterial assemblages are affected by elevated CO2 concentrations and inorganic nutrients. In a large-scale experiment, bacterioplankton could keep productivity and community structure unaltered by adapting the gene expression under CO2 stress. To maintain pH homeostasis, bacteria induced higher expression of genes related to respiration, membrane transport and light acquisition under low-nutrient conditions. Under high-nutrient conditions with phytoplankton blooms, such regulatory mechanisms were not necessary. These findings indicate that open ocean systems are more vulnerable to ocean acidification than coastal waters.

    Lastly, I used field studies to resolve how bacterioplankton is influenced by environmental changes, and how this leads to seasonal succession of marine bacteria. Using high frequency sampling over three years, we uncovered notable variability both between and within years in several biological features that rapidly changed over short time scales. These included potential phytoplankton-bacteria linkages, substrate uptake rates, and shifts in bacterial community structure. Thus, high resolution time series can provide important insights into the mechanisms controlling microbial communities.

    Overall, this thesis highlights the advantages of combining molecular and traditional oceanographic methodological approaches to study ecosystems at high resolution for improving our understanding of the physiology and ecology of microbial communities and, ultimately, how they influence biogeochemical processes.