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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Exploring the time-loss bias: Identification of individual decision rules and heuristics.

Borg, Anna January 2019 (has links)
Previous research has demonstrated that intuitive judgments of timeloss are often biased: overestimated when a high speed is slowed down and underestimated when a low speed is decreased further. Yet, no findings provide cognitive explanations of the bias. The present study (a) collected numerical judgments of time-loss by assigning participants to seven speed matching problems, and (b) collected verbal protocols of participants judgment processes. To identify different decision rules on the individual level, a spectral analysis of judgments was used. The findings show that the ratio rule was most frequently used and similar to the well researched time-saving bias, a ratio heuristic and a difference heuristic could model a majority of the timeloss bias. The validity of the method is supported by a significant correspondence between the spectral analysis measure and the qualitative analysis for consistent participants. By including affect as a third variable, future research could get a closer understanding of the bias effect in real life and consequently develop strategies that can improve road safety.
2

Design and Analysis of Decision Rules via Dynamic Programming

Amin, Talha M. 24 April 2017 (has links)
The areas of machine learning, data mining, and knowledge representation have many different formats used to represent information. Decision rules, amongst these formats, are the most expressive and easily-understood by humans. In this thesis, we use dynamic programming to design decision rules and analyze them. The use of dynamic programming allows us to work with decision rules in ways that were previously only possible for brute force methods. Our algorithms allow us to describe the set of all rules for a given decision table. Further, we can perform multi-stage optimization by repeatedly reducing this set to only contain rules that are optimal with respect to selected criteria. One way that we apply this study is to generate small systems with short rules by simulating a greedy algorithm for the set cover problem. We also compare maximum path lengths (depth) of deterministic and non-deterministic decision trees (a non-deterministic decision tree is effectively a complete system of decision rules) with regards to Boolean functions. Another area of advancement is the presentation of algorithms for constructing Pareto optimal points for rules and rule systems. This allows us to study the existence of “totally optimal” decision rules (rules that are simultaneously optimal with regards to multiple criteria). We also utilize Pareto optimal points to compare and rate greedy heuristics with regards to two criteria at once. Another application of Pareto optimal points is the study of trade-offs between cost and uncertainty which allows us to find reasonable systems of decision rules that strike a balance between length and accuracy.
3

The Canadian C-Spine Rule and CT-Head Rule Implementation Studies: A Psychological Process Evaluation

Perez, Richard 10 March 2011 (has links)
The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.
4

Influences of Personal Information, Public Information, and Extra-pair Paternity on Breeding Site Fidelity in a Songbird

Campomizzi, Andrew James 2011 August 1900 (has links)
I investigated the role of extra-pair paternity on use of public information and the interaction between public information and personal information for patch fidelity decisions. It is unknown if songbirds use public information about the number of conspecific fledglings for patch fidelity decisions when extra-pair paternity is uncommon. I tested if probability of patch fidelity was associated with (1) number of fledglings in adjacent territories (public information), and (2) number of fledglings raised with a social mate (personal information). I used logistic regression to predict probability of patch fidelity of males and females based on the 2 uncorrelated predictor variables (Spearman’s rank correlation, S = 21895.28, n = 50, P = 0.723, r = –0.051). I monitored patch fidelity of 107 territories, counted the number of fledglings in each territory, and assessed parentage of 102 young from 36 nests for white-eyed vireos (Vireo griseus) from 2008–2010 in a 100 ha patch of woodland in central Texas, USA. I excluded the social male as the father of 3 of the 102 young and did not exclude any of the social females as the mother with parentage analysis using 6 microsatellite loci. The number of fledglings in adjacent territories was not a good predictor of probability of patch fidelity for males (beta 1 = 0.166, df = 35, P = 0.247, Nagelkerke’s R2 = 0.054) or females (beta 1 = 0.121, df = 17, P = 0.670, Nagelkerke’s R2 = 0.016). The number of fledglings raised with a social mate was also not a good predictor of probability of patch fidelity for males (beta 1 = –0.296, df = 43, P = 0.360, Nagelkerke’s R2 = 0.029), whereas it was a good predictor for females (beta 1 = 1.281, df = 21, P = 0.048, Nagelkerke’s R2 = 0.409). The dominant ecological concepts for explaining site fidelity in songbirds, win-stay lose-switch (based on personal reproductive success with a social mate) and public information, did not predict probability of patch fidelity well for male white-eyed vireos. The win-stay lose-switch model, but not public information was a good predictor of probability of patch fidelity for females. My results suggest that use of public information may depend on frequency of extra-pair paternity. Males may primarily use other information for patch fidelity decisions beyond reproductive success of conspecifics for patch fidelity decisions in some circumstances. My results support the need to ensure high levels of nesting success for females to return and maintain populations in areas managed for breeding songbirds for conservation efforts to be successful.
5

The Canadian C-Spine Rule and CT-Head Rule Implementation Studies: A Psychological Process Evaluation

Perez, Richard 10 March 2011 (has links)
The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.
6

The Canadian C-Spine Rule and CT-Head Rule Implementation Studies: A Psychological Process Evaluation

Perez, Richard 10 March 2011 (has links)
The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.
7

The Canadian C-Spine Rule and CT-Head Rule Implementation Studies: A Psychological Process Evaluation

Perez, Richard January 2011 (has links)
The Canadian C-Spine (CS) and CT-Head (CT) Rules are tools aimed at improving the accuracy and efficiency of radiography use in emergency departments. This study evaluated whether the Theory of Planned Behaviour (TPB) could explain the inconsistent results from implementation studies of these two rules at 12 Canadian hospitals, where the same intervention resulted in a significant reduction in CS radiography but not CT radiography. It was demonstrated that the TPB model’s proposed relationships between constructs and behaviour could explain the ordering of CS but not CT radiography. However, after examining longitudinal changes of the TPB constructs, it was clear that these changes could not explain the changes in CS radiography ordering. Overall, TPB is unlikely to suggest important ways by which to improve radiography use, for CT because its constructs are not related to radiography ordering, and for CS because of high baseline levels of intention to clinically clear.
8

La formation endogène de coalitions peut-elle être un remède à la tragédie des communs : Une étude expérimentale / The endogenous coalition can be a solution to the tragedy of common ? : An experimental study

Rhouma, Oussama 13 January 2014 (has links)
La gestion d'une ressource commune soulève souvent le problème de leur surexploitation qui aboutit en général à leur épuisement. Nous étudions dans ce travail l'impact de formation de coalition sur l'investissement dans la ressource commune. Nos premiers résultats viennent de la résolution du modèle d'investissement qu'on a modifié pour permettre la formation de coalition. L'optimum social est toujours dans la formation de la plus grande coalition, cependant l'équilibre de Nash dépend du nombre de joueurs dans le jeu. Nous avons choisi le cas pour lequel l'équilibre Nash et l'optimum social coïncident. Pour cet exemple nous démontrons que la formation de la plus grande coalition permet d'investir moins dans la ressource et garantit le gain total le plus. On montre aussi que toute formation autre que les cinq singletons est une amélioration par rapport au jeu standard. Les résultats expérimentaux viennent confirmer nos calculs théoriques. En effet les joueurs forment des coalitions et investissent moins dans la ressource. La structure de départ et la règle de décision d'investissement ne change pas le résultat final. / The management of commons pools resources raises the problem of their over-exploitation which degenerates in general into their exhaustion. We study the impact of coalition formation in the investment on common pool resource. Our first result from resolution of our model show that social optimum is always in the formation of the biggest coalition, however Nash equilibrium depend on number of player in the game. We choose case in which Nash equilibrium and social optimum coincide. For this example we demonstrate that in forming the biggest coalition we invest less in CPR and the total payoff is the greatest from all structure. We demonstrate also that comparing to the game without coalition formation (standard case) any structure other then singletons coalitions was an amelioration (less investment and greeter group payoff). Our first experiment with two treatments (veto & dictator) confirms our theoretical study : players form groups, decrease their investment in CPR and increase their payoff. The second experiment show that nether we change first group structure, the result is the same. We demonstrate also that decision rules don't affect final results.
9

Prédire l’infection sévère lors des épisodes de neutropénie fébrile post-chimiothérapie de l’enfant : développement d’une règle de décision clinique / Prediction of severe infection in children with chemotherapy-induced febrile neutropenia : development of clinical decision rule

Delebarre, Mathilde 23 September 2016 (has links)
Contexte: Le pronostic des neutropénie fébrile (NF) post-chimiothérapie de l’enfant a été amélioré par une antibiothérapie à large spectre systématique. Cependant des infections sévères ne surviennent que dans 15-25% des cas. Il a été recommandé en 2012 de faire évoluer la prise en charge en tenant compte du risque infectieux en utilisant des règles de décision clinique (RDC). Nous avions montré que les outils publiés pour distinguer ce risque étaient peu performants, non validés ou non applicables sur notre population. Une nouvelle RDC (score) permettant de distinguer les épisodes de NF à bas risque d’infection sévère a été construite. Cette RDC a été validée en interne. Compte tenu des différences mises en évidence dans les populations de tumeurs solides et d’hémopathies, il pourrait être pertinent d’utiliser un arbre de décision clinique pour classer le risque infectieux dont la première division serait le type de cancer et de valider cette nouvelle RDC.L’objectif de ce travail était de calibrer cette RDC sous forme d’arbre et de la valider sur un échantillon multicentrique pour distinguer les enfants avec NF à bas risque d’infection sévère. Méthodes: La première étape a été d’évaluer la méthodologie de développement des RDC déjà publiées pour identifier d’éventuelles limites méthodologiques. Ensuite, nous avons décrit les différences entre les hémopathies ou avec les tumeurs solides. Puis, la nouvelle RDC a été calibrée sous forme d’un arbre de décision à l’aide du logiciel Sipina. Sa performance a été évaluée en termes de sensibilité (Se), spécificité (Sp), et rapport de vraisemblance négatif (RVN).En parallèle, un protocole de validation multicentrique prospectif a été monté, avec pour objectif une Se proche de 100% et un RVN inférieur à 0,1. Il a été validé par le CCTIRS et par la CNIL. Il a été financé par la Ligue Contre le Cancer (72 000 euros). Trente et un centres ont été recrutés. La RDC n’a été appliquée qu’a posteriori ; la prise en charge de cette population n’a donc pas été modifiée. La performance de la RDC entre la population de validation et construction a été analysée en termes de Se, Sp, RVN. L’évaluation des pratiques de prise en charge des NF post-chimiothérapie de l’enfant a été faite en parallèle sous la forme d’une enquête nationale, dans la perspective d’une étude d’impact ultérieure.Résultats: L’étude de la méthodologie des RDC déjà publiées a montré que les critères de développement d’une RDC étaient respectés dans 71% des cas (médiane). Une RDC avait atteint le plus haut niveau d’évidence, mais sa population de construction était différente de la nôtre et cette RDC n’était pas reproductible sur notre population. Il existait 2 à 3 fois plus d’infection sévère chez les patients atteints d’une hémopathie maligne. Deux arbres de décision ont donc été construits pour différencier le risque d’infection sévère. Pour les patients avec une tumeur solide il avait des Se de 96%, Sp de 59% et RVN à 0,07, pour ceux avec une hémopathie maligne, il avait des Se de 99%, Sp de 52% et RVN à 0,03. Les inclusions de la validation multicentrique se sont déroulées de janvier 2012 à mai 2016. 1806 épisodes ont été inclus (333 infections sévères, 18,4%). L’application de la RDC a été faite a posteriori(en cours). L’enquête nationale menée en parallèle sur la prise en charge faite en pratique dans les centres français a montré une grande variabilité de prise en charge notamment dans les définitions de la neutropénie et de la fièvre. Un travail doit être initié avec la Société Française des Cancers de l’Enfant pour uniformiser la prise en charge des NF et déterminer le type d’allègement thérapeutique à proposer en vue de l’étude d’impact, en utilisant cette RDC. Conclusion: Les étapes de construction et de validation de cette nouvelle RDC ont été réalisées en respectant les standards méthodologiques. Une étude d’évaluation de l’impact de la RDC devra être mise en place pour atteindre le plus haut niveau d’évidence. / Purpose: Chemotherapy-induced febrile neutropenia (FN) is known to be a risk for severe infection and death in the absence of prompt and appropriate antibiotic therapy. Immediate hospitalization for rapid institution of empirical broad-spectrum intravenous antibiotic therapy has led to reduce the mortality. However, documented or severe infections occur in only 15-25% of cases. In 2012 paediatric guidelines suggested to adapt the management of FN episodes to the infectious risk. In a previous work, none of the published clinical decision rules (CDRs) to rule out severe infections have been validated and have only rarely been tested in an external set of children. The methodological standards used to derive and validate these CDRs were a real concern. A new CDR was previously derived as a scoring system in Lille to classify the patients at high or low risk of severe infection, with a dataset collected in 2 centers in Lille, in following methodological standards. Differences between solid tumours and blood cancers were observed in children with FN for numbers and types of infections. As a result, we considered relevant to build a decision tree model to predict the low risk for severe infection with a first division that could be the type of cancer. This new decision rule was already validated in an internal set of data, but required an external validation.The aim of this project was to calibrate the CDR as a decision tree and validate its performance a posteriori in an external set of patients, using prospectively collected data from multiple centers.Methods: the methodological standards of available CDRs were first analysed. The new CDR derived on a bicentric dataset was reused to calibrate the CDR as a decision tree, using Sipina software. A prospective multicentric observational protocol funded by 72000€ provided by “la Ligue Contre le Cancer” was developed for an external validation of the CDR to expect near 100% sensitivity (Se) and a negative likelihood ratio (LR) below 0.1. The ethical regulation was followed. Thirty-one centers were recruited in France (27/30 referent centers for management of children with cancer, and 4 proximity centers fit to manage children with FN). The CDR was not applied to the included patients, and remained confidential. The data were collected on an e-CRF “capture system”. The data were captured by an assistant of clinical research and controlled by a physician researcher after the monitoring of the data in all centers. The CDR was a posteriori applied on the dataset. The performance of the CDR between validation and derivation sets of patients was analysed in terms of Se, specificity (Sp) and negative LR.Results: the methodological standards of development of a CDR were not always followed for the development of the published CDR predicting infection for FN in children. Only one CDR followed all criteria and reached the highest level of evidence, but this CDR was built in a very different population from our and was not reproducible. A decision tree model of the CDR was built to distinguish children with FN at low risk of severe infection. For children with solid tumours, the CDR had 96% Se, 59% Sp, and a negative LR at 0.07. For children with blood cancers, the CDR had 99% Se, 52% Sp, and a negative LR at 0.03.For external validation, inclusions started in 2012 until May 2016. Of the 31 centers, 23 included 1806 cases (333 severe infections [18.4%]). The retrospective application of the CDR on all included case in ongoing. A national survey was also conducted as the same time to analyse the real management of children with FN in France in order to determine the type of management that could be proposed for low risk patients when the CDR will be tested in an impact study.Conclusion: the different steps for the construction and validation of the new CDR were conducted following standards. This CDR is in progress to reach the highest level of evidence.
10

Individual differences and universal condition-dependent mechanisms

Lewis, David Michael 24 September 2013 (has links)
This study investigated the hypothesis that universal psychological adaptations produce personality variation when individuals differentially face adaptive problems that shifted the cost-benefit tradeoffs of alternative personality strategies in ancestral environments. The current research tested the hypothesis that psychological adaptations calibrate individual differences in neuroticism as a functional response to social exclusion. If psychological adaptations produce neuroticism in response to social exclusion, and heritable components of individuals' social partner value influence their likelihood of being excluded, then individual differences in social partner value should yield heritable differences in neuroticism. Three conceptually distinct sub-studies tested hypotheses derived from this conceptual framework. Sub-study 1 tested the relationship between individuals' mate value, social exclusion, and neuroticism. Individuals' mate value exhibited both a direct effect on neuroticism and an indirect effect through the experience of social exclusion. Sub-study 2 investigated sexual jealousy as a specialized class of neuroticism in response to infidelity. As predicted, individuals' mate value predicted the likelihood of their partners' infidelity and their own mate guarding behavior. Sub-study 3 manipulated the threat of infidelity to test for functional shifts in neuroticism in response to relationship exclusion. Participants read vignettes describing their mates' certain fidelity, uncertain fidelity, and certain infidelity, and wrote what they would think, feel, say, and do in response to each scenario. An independent sample assessed participants' personalities based on these cognitive, affective, and behavioral responses. As predicted, participants' neuroticism tracked relationship exclusion; participants' neuroticism levels increased with infidelity threat. These findings are consistent with the hypothesis that a universal psychological mechanism adaptively calibrates neuroticism levels in response to relationship exclusion; the certain absence or presence of the adaptive problem of relationship exclusion should deactivate or activate anti-exclusion mechanisms in all individuals. Above this situational effect, under conditions of uncertain infidelity -- in which the threat of infidelity would have ancestrally varied with men's (but not women's) mate value -- men's mate value predicted their neuroticism. Together, these findings support the hypothesis that humans possess psychological adaptations that functionally calibrate neuroticism levels. More broadly, they highlight the heuristic value of an evolutionary adaptationist framework for the study of personality and individual differences. / text

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