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- Axelsson, Anton, 1981-
(författare)
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Knowledge elicitation as abstraction of purposive behaviour
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Researchers use knowledge elicitation methods to document expert knowledge for the primary purpose of understanding cognitive processes and with this understanding, technical solutions to resolve human factors issues can be produced. This dissertation offers a novel perspective on knowledge elicitation as an abstraction process. Such a theoretical framework has emerged by consolidating the ecological approach of Brunswikian psychology with the ideas of tacit and personal knowledge of Polanyian epistemology. Traditionally, knowledge elicitation has been considered an extraction process in which knowledge can be readily transferred from one individual to another. Here, this traditional position is rejected in favour of Polanyi’s premise that much of the knowledge individuals possess is tacit in nature, which implies that it cannot be documented easily, expressed in explicit form or explained. In this dissertation, knowledge is characterised as a personal process of knowing, highlighting context as a subjective knowledge structure of personal experiences that is formulated implicitly and indirectly over time through a dynamic interaction with the environment. Therefore, tacit knowledge cannot be articulated or shared; however, learners can be inspired by observing other individuals' purposive (i.e., goal-directed) behaviours and thus shape their own tacit knowledge once they practise the observed skills and develop conceptual understanding through reasoning about the learning process. Knowledge elicitation thereby makes use of observations, questions, or more structured process tracing methods in environments familiar to the observed individuals to elicit purposive behaviour from them. Accordingly, functional descriptions can be produced in this process that further conceptual understanding of a particular domain. Knowledge elicitation procedures are a powerful set of methods for reaching such functional descriptions. Moreover, by understanding the resulting knowledge elicitation data as an abstraction derived from multiple collection points in the same environment, the focus shifts from purely subjective mental constructs to the impact of environmental constraints.
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- Fraser, Magdalena
(författare)
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People of the Dolmens and Stone Cists : An archaeogenetic Investigation of Megalithic Graves from the Neolithic Period on Gotland
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The study of ancient genomics of pre-historic human remains has in recent years offered unprecedented knowledge regarding pre-historic migration and population structure on the European continent which has fundamentally altered the current views in the archaeological community. However, the merging of the two fields, archaeology and genetics, is still in its infancy and much work is still needed in order for these fields to integrate. In this thesis I explore how genetic analyses, in combination with contextual radiocarbon dating and isotopic analyses for diet and mobility can be used to investigate demographic events on a local and regional level. This is done through the investigation of people buried in five previously excavated megalithic tombs on the Island of Gotland dated to the Neolithic period. I present the genomic population structure and archaeological background for the pre-historic European reference data and show how this is used to investigate population continuity, demographic shifts, cultural duality, and admixture for local and regional contexts. I present new data and explore the Strontium-baseline for the Gotland biosphere which is used for the mobility analyses. I show that mitochondrial haplogroup data is especially useful in combination with isotopic data, and radiocarbon dating for investigation of demographic shifts on a larger scale. I also show that genomic data gives unique insights into the individuals’ life history which, together with the established demographic background allows for fine scale investigation of population demographic events within and between different archaeological contexts. Finally I show that the different Neolithic contexts on Gotland to a large extent involves immigration of new groups to the island, and that the contextual breaks seen in the archaeological record during the Neolithic period are connected with cultural and population demographic shifts. This dissertation demonstrates that genomic analyses, in combination with archaeology and isotopic analyses, as well as contextual osteological analyses and radiocarbon dating, present unique insights into the life history of the actual people who lived the lives we try to understand.
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- Mårdh, Selina
(författare)
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Cognitive erosion and its implications in Alzheimer’s disease
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present thesis was twofold, first to map the semantic memory decline in Alzheimer patients over time, second to take the patient’s perspective and create a multifaceted picture of the individual with Alzheimer’s disease through the study of memory, awareness, central coherence and emotions. Further issues concerned how Alzheimer individuals handled their cognitive erosion in everyday life and if they were well calibrated with their spouse in disease related matters.Two studies were performed, the first involved a longitudinal study of sematic deterioration, the second had a mixed methods design involving both quantitative and qualitative measures as in neuropsychological assessment and interviews.Through the longitudinal study it could be concluded that the nature of semantic deterioration is best described as loss of memory information rather than problems in accessing the information. It was further concluded that semantic concepts gradually lose their specific features during course of illness.The results from the second study revealed that the Alzheimer individuals were aware of their disease although they could not foresee the implications of their cognitive shortcomings in their everyday life. They evidenced weak central coherence, in that they were unable to infer details into a meaningful whole. This implies that they perceive their surrounding world in a fragmented way as consisting of separate objects rather than a comprehensible context. Concerning emotions it was found that they responded to negatively valenced words in the same way as normal ageing individuals, although being impaired in their response to positively and neutral words. Finally, the Alzheimer individuals and their spouses were not well calibrated regarding disease related issues.The findings of the present thesis have important clinical implications and gives valuable input to the understanding of the individual with Alzheimer’s disease.
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- Suresh, Shyam, 1990-
(författare)
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Developments of Topology Optimization Methods for Additive Manufacturing involving High-cycle Fatigue
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Additive manufacturing (AM) is a versatile manufacturing process which is gaining popularity in the automotive and aerospace industries. Through AM one can manufacture complex structures and combined with topology optimization (TO) a powerful design tool that provides great freedom in geometric form emerges. The goal of the research presented in this thesis is to develop new TO methods that consider specific properties related to AM for metals. In particular, anisotropy, non-homogeneity in the form of surface effects, and constraints on high-cycle fatigue (HCF) damage are treated. In the first paper of the thesis, an HCF constraint is introduced into a TO problem where the total structural mass is minimized. The HCF model is based on a continuous-time approach in contrast to more conventional cycle-counting approaches. It is based on the concept of a moving endurance surface, and a system of ordinary differential equations is used to predict the fatigue damage at every point in the design domain. The model is capable of handling arbitrary load histories, including most non-proportional loads. Gradient-based optimization is utilized, and the fatigue sensitivities are determined by the adjoint method. In the subsequent papers, several extensions are made to the original HCFconstrained TO problem: The HCF model is extended so that it is applicable not only to isotropic materials but also to transversely isotropic materials. The anisotropic properties are manifested in the constitutive elastic response and in the fatigue properties. Acceleration of fatigue and sensitivity analyses by extrapolation is introduced, making the treatment of an unlimited number of load cycles possible. Simultaneous optimization of build orientation and topology, considering stress- and HCF constraints, is performed. For better prediction of fatigue, especially for non-proportional loads, the original continuous-time HCF model is modified using a quadratic polynomial endurance function. In the final paper, a new TO method, taking surface layer effects into account, is introduced. This essentially models the impaired mechanical properties observed in as-built AM components compared to components having polished surfaces. Numerical test problems as well as application-like problems are solved in all papers to exemplify the applicability of the developed TO methodology.
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- Wallin, Kim, Doktorand, 1978-
(författare)
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Balancing structure and flexibility in the ambulance service : the pursuit of professional judgement in caring and learning
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of this thesis was to describe the conditions for learning inthe ambulance service during clinical practice, and to develop an understanding of how to support the professional development of caring in this context.The findings of this thesis are based on four qualitative interview studies.The study group consisted of 28 specialist ambulance nursing students (I), 20 preceptors (II), 27 preceptors (III), and 16 specialist ambulance nursingstudents (IV), from all parts of Sweden. The data were collected by individual, dyadic, and focus group interviews. The study designs and analytical approach were guided by the critical incident technique, latent content analysis, reflexive thematic analysis, and a phenomenographic approach.The findings indicate that the contextual complexities of ambulance care contradict the students’ fundamental need to independently care for the patients in their development of all domains of knowledge. Caring and learning in the ambulance service requires a structured approach in medical, technical, and practical aspects to create a basic security for preceptors and students in dealing with the diversity in care situations, patient needs, and student needs. However, this structured approach may hinder an individualized and situationally adapted approach unless the preceptors and students develop a flexible and reflective questioning approach in the phronetic domains of knowledge. The support, educational strategies, and learning objectives needed for enhancing educational clarity and quality during clinical practice in ambulance care are presented at an organizational, environmental, situational, and interpersonal level.It is proposed in the conclusions that a reflective questioning approach and an embodied understanding of ambulance service work supported by critical reflections are fundamental to support professional development in this field. Higher education institutions and the ambulance departments should address the professional development as a mutual concern, where supporting the development of a caring competence should be viewed as a lifelong continuum of learning. The expanding scope of ambulance care requires professional judgement to manage the ethical complexities of clinical decision-making to safeguard the patient perspective in ambulance care.
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- Wallin, Ragnar
(författare)
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Optimization Algorithms for System Analysis and Identification
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Optimization is a powerful and frequently used tool in many fields of research. In this thesis two relevant and important problems from robust control system analysis and system identification are solved using optimization algorithms.Many of the most important examples of optimization in control and signal processing applications involve semidefinite programming with linear matrix inequality constraints derived from the Kalman-Yakubovich-Popov lemma. For realistic examples these semidefinite programs have a huge number of variables making them intractable for general purpose solvers. Three customized algorithms for this class of optimization problems are presented and compared to each other. Preprocessing of the semidefinite program that may improve numerical issues are discussed. This preprocessing also makes it possible to relax some assumptions usually made on the semidefinite program. Moreover, it is shown how to use the algorithms for other stability regions than the left half plane.Even though missing data is quite common in many control and signal processing applications, most system identification algorithms do not address this phenomenon in a good way. This often results in parameter estimates with a large bias. In this thesis the maximum likelihood criterion for identication of Autoregressive models with an exogenous signal subject to missing data is investigated. Two algorithms for identifying the models are presented and are compared to the expectation maximization algorithm. From optimality conditions is computed estimates of the asymptotic variance of the parameter estimates. In addition, it is discussed how a criterion equivalent to the maximum likelihood criterion opens up the possibility to apply a wide range of other optimization algorithms to the estimation problem. It is also shown what property of the data it is that determines why one model is more likely to have produced the data than another. Finally, the multiple optima problem is addressed.
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