Sherlock Holmes har visat på slutledningskonsten att koppla ledtrådar från en situation till personlighet. Är det då inte möjligt att säga mer om en person på bas av föremål som är relativt statiska/konsistenta i ens användning över hela dagen? Praktiserandet av profilering baseras på sambandet mellan personlighet och beteende men forskning har visat att beteenden inte alltid speglar vår personlighet. Denna studie syftade till att undersöka om personlighet kunde användas som prediktor till föremål. En förstudie med sju deltagare gjordes för att utforma en checklista med 48 föremål som sammanfogades med Big Five till en webbenkät. Webbenkäten besvarades av 449 kvinnor. De 48 föremålen användes som beroende variabler i simultana logistiska regressionsanalyser varav 15 var signifikanta. Modellerna gav studien stöd för att personlighet som prediktor påverkar sannolikheten av att bära eller inte bära 15 föremål. Kompletterande studier bör göras för att utforska potentiellt samband mellan beteenden och föremål.

Sherlock Holmes har visat på slutledningskonsten att koppla ledtrådar från en situation till personlighet. Är det då inte möjligt att säga mer om en person på bas av föremål som är relativt statiska/konsistenta i ens användning över hela dagen? Praktiserandet av profilering baseras på sambandet mellan personlighet och beteende men forskning har visat att beteenden inte alltid speglar vår personlighet. Denna studie syftade till att undersöka om personlighet kunde användas som prediktor till medhavda föremål. En förstudie med sju deltagare gjordes för att utforma en checklista med 48 föremål som sammanfogades med Big Five till en webbenkät. Webbenkäten besvarades av 449 kvinnor. De 48 föremålen användes som beroende variabler i simultana logistiska regressionsanalyser varav 15 var signifikanta. Modellerna gav studien stöd för att personlighet som prediktor påverkar sannolikheten av att bära eller inte bära 15 föremål. Kompletterande studier bör göras för att utforska potentiellt samband mellan beteenden och föremål. / <p>Formalia uppdaterad</p>

According to the predictive coding approach to perception, the brain uses predictions based on previous experience to optimise perception, by allocating more computational resources to important or unexpected stimuli. Overall, predictions allow faster and more accurate recognition, but occasionally, when the prediction is incorrect, it may lead to a misperception. The aim of this thesis was to investigate the influence of top - down processes on perceptual decisions. I utilised misperceptions as a signature of those top - down influences and Signal Detection Theory to assess their size, type and direction. I used Electroencephalography to determine the stage of information processing at which different types of predictions influence sensory processing.The empirical studies are clustered around Topic 1: Influence of Predictions on Perception, Topic 2: Types of Predictions and Topic 3: Value as Modulator of Perception.Studies clustered in Topic 1 analysed and quantified the influence of predictions on perceptual decisions and showed that misperceptions can be triggered by wrong predictions only in very specific circumstances. In particular, misperceptions occurred only if there was some degree of correspondence between the wrong prediction and the sensory input. Otherwise, predictions were easily rejected, increasing the overall accuracy. I also demonstrated that misperceptions were most likely to happen in a window on the continuum of input quality where the stimulus - related uncertainty was highest. Topic 2 comprised experiments investigating different types of predictions and their interaction. Behavioural (but not EEG) results revealed interference between passive and active expectations. The early event related (ERP) components N1 and P2, as well as the P300, were all modulated by expectations. Expected events either increased or decreased the P300 amplitude, depending on whether the expected item was predictable and thus ignored, or awaited and thus flagged for further processing. This suggests that P300 might be an index of top - down resource allocation. Experiments within Topic 3 studied the influence of values, as examples of executive processes, on perceptual decisions, using either natural or acquired high - value stimuli. The results suggested that the process of recognition is adjusted in a top - down manner to account for the cost and benefit values related to different outcomes. The trade - off between processing time and accuracy is not fixed, but can be adjusted to optimise recognition in the task at hand. Furthermore, value can change the focus of perception, resulting in different elements of the sensory input being amplified or ignored. Overall, these results showed that misperceptions are 'intelligent mistakes' - a by - product of a top-down, prediction - based optimisation strategy that decreases the computational load, while increasing accuracy and improving the allocation of computational resources.

Research has examined how encoding or retrieval factors affect metamemory. Few studies have manipulated both an encoding and a retrieval factor in the same paradigm. The current experiments examined which factor had a greater impact on metamemory when both were manipulated. Attention was manipulated during encoding and Retroactive Interference was manipulated at retrieval.Two lists of word pairs were studied, with the second list including both new pairs and cues from the first list re-paired with a new target. The attention manipulation occurred when studying the first list in which participants denoted when one tone sequence changed to another. Participants gave predictions about the likelihood of future recall of the original targets either immediately following study (JOL) or in a separate phase after studying all pairs (DJOL). The Modified Opposition Test (MOT) was used in which a hint was used to direct participants to the correct list for recall. After all pairs were studied and predicted, participants completed a cued-recall test. In Experiment 1, DJOLs were used because they are collected between encoding and retrieval. Both factors impacted memory, but DJOLs were only impacted by the retrieval factor. A dissociation between memory and metamemory under retroactive interference was expected and replicates prior research (Eakin, 2005). In Experiment 2, JOLs were added; JOLs are measured during the encoding phase, allowing the impact of the encoding factor to be observed. Replicating Experiment 1, memory was affected by both the encoding and retrieval factor, but JOLs were impacted by the retrieval factor. Another comparison using a standard cued-recall test instead of the MOT, showed that JOLs were no longer influenced by the retrieval factor, but they still did not vary with attention. The results conclusively suggest that metamemory was not based on encoding factors, even when the retrieval factor is not influencing the predictions. Koriat’s (1993, 1994) accessibility heuristic can explain these results. Predictions were based on how much information came to mind when the prediction is made, regardless of whether that information is correct. Furthermore, metamemory predictions are based on heuristics that do not always follow memory outcomes.

Predicted fear is the amount of fear a person expects to experience in a given situation. Predictions can be either accurate or inaccurate in comparison to what the person actually experiences in the situation. This two-part analog study was an extension of Rachman's match/mismatch model of overprediction theory. In the first part, college students who overpredicted their fear of a live snake were compared with a control group of students who either underpredicted or accurately predicted their fear of the same snake. Comparisons were made on self-report, physiological, and behavioral measures of anxiety to assess the relationship between these measures and the tendency to overpredict fear. In the second phase of the study, overpredictors and control subjects were randomly assigned to either a feedback or no feedback group. At issue was whether feedback about the accuracy of predicted fear of a snake facilitated correct matches and fear reduction on subsequent exposure trials in comparison to the effects of exposure alone. Results showed that providing feedback did not hasten correct matches. However, in keeping with the views of Rachman (1994) and others, I did find (a) a larger number of overpredictors than underpredictors, (b) an increase of accuracy of predictions over trails, (c) a decrease in the participants' levels of fear over trials.

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Finite element human body models have in recent years become widely used in the area of vehicle safety evaluations. They make it possible to predict injury risk in specific areas, down to the organ level in the human body. An existing human body model, SAFER HBM includes a rib cage representing an average male. However, humans have a large variability in rib geometry and material properties leading to uncertainties in non-linear phenomena such as rib fracture risk. Hence, it cannot be known if predictions based on an average male representation are applicable to other similar individuals. In simulation studies with the SAFER HBM, rib cortical bone thickness, rib cross-sectional width, and rib cortical bone material properties have been identified as the most influential for the magnitude of rib strains and thus, they have a large influence on the strain-based rib fracture risk. This means that the predicted injury outcome is sensitive to the particular rib properties of an individual, and in a real-world scenario, a distribution of injury outcomes is expected across a population. Knowledge of the injury risk distribution can aid vehicle designers in developing safer vehicles. This distribution can be found through repeated human body model simulations with various rib properties, but due to the lengthy simulation times, this is not feasible. This thesis aims to predict human body model rib strain histories, given variations in the three biomechanical parameters, rib cortical bone thickness, rib cross-section width and rib cortical bone material with the help of graph neural networks (GNNs) for both single and mixed impact scenarios. Several variations of GNNs were used and implemented with help of PyTorch and PyTorch Geometric. An extensive hyperparameter study was performed on a small part of one human body model rib, to find the optimal combinations of hyperparameters and GNNs. The data used in training and evaluation of the networks was generated in LS-DYNA with SAFER HBM v10 and post-processed in Meta post processor. To be able to generate many training examples, the HBM was subjected to a simplified impact scenario consisting of a pendulum impact to the chest. As final verification, the trained GNNs were applied to predict rib strains in a vehicle impact scenario. Evaluation of the GNNs' prediction accuracy on the whole rib cage for all impact scenarios was made by studying the root mean square error along with differences in predicted and actual peak strain, rib fracture risk, time the peak strain occurs and the euclidean distance between the locations within the rib of real and predicted peak strains. The results showed that it is possible to accurately predict strain histories. Further, a multilayer perceptron (MLP) model consistently achieved the lowest errors in all measurements for mixed impacts. However, the trained model produced slightly unexpected errors for test data extracted from vehicle simulations compared to simplified simulations. This is an indication that retraining the model on data from vehicle simulations may be necessary. In conclusion, this thesis has shown the possibility to predict strain histories from a SAFER HBM rib cage extracted from simplified simulations and simulations including the full vehicle model, the SAFER HBM and all safety systems, to investigate the effects of human variability in the rib cage.

La musique et la parole possèdent toutes deux un degré d’organisation temporelle i.e. de régularité dans le temps. Les stimuli de nature rythmique ont la particularité de pouvoir être anticipés par le cerveau et des études en linguistique et neurosciences ont montré que plus le cerveau est capable d’anticiper les évènements auditifs, meilleure est la qualité du traitement des stimuli. Les enfants sourds, bien que bénéficiant d’un input auditif de plus en plus précis grâce aux implants cochléaires et d’une prise en charge précoce, n’atteignent pas des niveaux de langage homogènes et souffrent de difficultés de perception en milieux bruyants ou lors de conversations. La situation conversationnelle présente un contexte complexe, nécessitant l’activation de la voie audio-motrice pour anticiper et s’adapter aux variations de la parole de son interlocuteur notamment au niveau temporel. Dans ce travail de thèse, nous avons cherché à analyser, grâce à des mesures électrophysiologiques et comportementales, si un entrainement rythmique actif de 30 minutes, pouvait avoir un effet sur les capacités de perception et d’accommodation temporelles de l’enfant sourd dans une tâche de dénomination en alternance avec un partenaire virtuel. Nous avons également testé les capacités rythmiques de ces enfants à différents niveaux de complexités. Les résultats montrent que les enfants sourds souffrent de difficultés à structurer les événements acoustiques selon différent niveaux de hiérarchie mais qu’un entrainement rythmique de 30 minutes versus une stimulation auditive, permet d’améliorer leurs compétences de perception et de production temporelles de la parole dans une situation d’interaction. / Music and speech both possess a certain degree of temporal organization i.e. a certain degree of regularity across time. Studies in linguistics and neuroscience have shown that the brain can extract regularities and use them to anticipate the forthcoming stimuli. It is furthermore established that the better the brain is able to anticipate auditory events, the better the quality of stimulus processing. Deaf children benefit from more and more precise auditory inputs due to advances in cochlear implants development, together with early rehabilitation interventions. However, a great majority of them do not achieve consistent language levels and have strong difficulties in noisy environments or conversations. The conversational situation presents a complex context, requiring the activation of the audio-motor path to anticipate and adapt to the variations of the speech of its interlocutor notably at the temporal level. In this thesis work, we have investigated the temporal perception and accommodation capacities of deaf children in a naming task alternating with a virtual partner, at both behavioral and electrophysiological levels. We have also tested whether an active rhythmic training lasting 30 minutes, could enhance these conversational abilities. Then, we have investigated the rhythmic abilities of these children at different levels complexities. The results show that deaf children suffer from difficulties in structuring acoustic events according to different levels of hierarchy but that a rhythmic training of 30 minutes versus an auditory stimulation, makes it possible to improve their skills of temporal perception and production of speech in a situation of interaction.

Antibiotic treatment failure might be due to bacterial resistance or suboptimal exposure at target site and there is a lack of knowledge on the interaction between antimicrobial pharmacodynamics (PD) and the immune response to bacterial infections. Therefore, it is crucial to develop tools to increase the understanding of drug disposition to better evaluate antibiotic candidates in drug development and to elucidate the role of the immune system in bacterial infections. Colistin is used as salvage therapy against multidrug resistant Gram-negative infections. In this work, a whole-body physiologically based pharmacokinetic model (WBPBPK) was developed to characterize the pharmacokinetics (PK) of colistin and its prodrug colistin methanesulfonate (CMS) in animal and human. The scalability of the model from animal to human was assessed with satisfactory predictive performance for CMS and demonstrating the need for a mechanistic understanding of colistin elimination. The WBPBPK model was applied to investigate the impact of pathophysiological changes commonly observed in critically ill patients on tissue distribution of colistin and to evaluate different dosing strategies. Model predicted concentrations in tissue were used in combination with a semi-mechanistic PKPD model to predict bacterial killing in tissue for two strains of Pseudomonas aeruginosa. Finally, a toxicokinetic (TK) model was constructed to describe the time course of E. coli endotoxin concentrations in plasma and the effect on pro-inflammatory cytokine release. The model adequately described the concentration-time profiles of endotoxin and its stimulation of IL-6 and TNF-α production using an indirect response model combined with a transit compartment chain with a tolerance component to endotoxemia. The WBPBPK model developed in this work increased the knowledge on colistin tissue exposure under various conditions and could be used in drug development process to assess antibiotic efficacy or to test new drug combinations. The model describing endotoxin TK and its effect on cytokines is a new tool to be further applied in longitudinal studies to explore the immune response cascade induced by bacterial infections. The methodology applied in this thesis contributes to the development of an integrated modeling framework including physiology, drug distribution, bacterial growth and killing as well as the immune response to infection.

Vector autoregressive (VAR) models are frequently used for forecasting and impulse response analysis. For both applications, shrinkage priors can help improving inference. In this paper we derive the shrinkage prior of Griffin et al. (2010) for the VAR case and its relevant conditional posterior distributions. This framework imposes a set of normally distributed priors on the autoregressive coefficients and the covariances of the VAR along with Gamma priors on a set of local and global prior scaling parameters. This prior setup is then generalized by introducing another layer of shrinkage with scaling parameters that push certain regions of the parameter space to zero. A simulation exercise shows that the proposed framework yields more precise estimates of the model parameters and impulse response functions. In addition, a forecasting exercise applied to US data shows that the proposed prior outperforms other specifications in terms of point and density predictions. (authors' abstract) / Series: Department of Economics Working Paper Series