Essays on the Information Acquisition of Doubt-Prone Decision Makers

There are many situations in which individuals have a choice of whether or not to observe the eventual outcome. In these instances, individuals often prefer to avoid observing the outcome. The standard von Neumann-Morgenstern (vNM) Expected Utility model cannot accommodate these cases, since it does not distinguish between lotteries for which outcomes are observed by the agent and lotteries for which they are not. I develop an axiomatic model that admits preferences for observing the outcome or remaining in doubt. I then use this model to analyze the connection between the agent\u27s attitude towards risk, doubt, and what I refer to as \u27optimism\u27. This framework accommodates a wide array of field and experimental observations that violate the vNM model, and that may not seem related, prima facie. For instance, this framework accommodates self-handicapping, in which an agent chooses to impair his own performance. Unlike other frameworks, this model accommodates self-handicapping without using notions of self-deception, cognitive dissonance and belief manipulation. It also admits a status quo bias without having recourse to framing effects or reference points. Furthermore, this framework accommodates behavior associated with anticipated regret, the Allais paradox and preferences for smaller menus, which are all difficult to reconcile with the vNM framework. In financial settings, this model accommodates a safe allocation bias, in which agents choose neither to buy nor short sell an asset for an interval of prices; this behavior has so far been explained using ambiguity aversion, which this model does not allow. Recently, experiments have been conducted in which dictators in dictator games who seem to exhibit preferences for fairness often switch to the selfish choice if they can avoid observing the recipients allocation. While the empirical findings of these experiments are difficult to reconcile either with models of Expected Utility or models of fairness, they fit the predictions of this model well. This framework accommodates all the well-known observations mentioned here and others described in the papers with a single, natural extension of the standard vNM model, and using the same assumption on preferences throughout

Cholesterol: Good or bad?

The importance of cholesterol and its essentiality is examined. Cholesterol is transported within the human organism by lipoproteins (chylomicrons, VLDL, LDL and HDL).The LDL, considered “bad cholesterol”, transport cholesterol from the liver to other tissus for their needs. However, HDL, the ”good cholesterol ”, transport back cholesterol to the liver to be recycled.Therfore, cholesterol is rather good for its various functions in the organism, and its deficiency may lead to cellular damage and a reduction in the synthesis of hormones such as testosterone and also vitamin D. Hypercholesterolemia should be considered an indicator of a health problem within the cells, that the organism is trying to fix by mobilizing cholesterol. Key words : Cholesterol, essentiality, lipoproteins (LDL, HDL)L’importance du cholestérol et son essentialité pour l’Homme est examinée Le cholestérol est transporté au niveau de l’organisme humain par des lipoprotéines (chylomicrons, VLDL, LDL et HDL). Principalement les LDL, considérées «mauvais cholestérol » transportent le cholestérol du foie vers les tissus pour leurs besoins; alors que les HDL «bon cholestérol » ramènent le cholestérol vers le foie pour le recycler. Ainsi, le cholestérol est plutôt bon pour ces différentes fonctions dans l’organisme, et sa carence peut entrainer des dommages cellulaires, ainsi qu’une réduction de la synthèse des hormones comme la testostérone ou encore la vitamine D. L'hypercholestérolémie devrait être considérée comme un indicateur d’un problème de santé au niveau des cellules, que le corps essaye de surmonter par mobilisation du cholestérol. Mots clés : Cholestérol, essentialité, lipoprotéines (LDL, HDL

Optimizirano povratnokoračno upravljanje momentom indukcijskog motora korištenjem genetičkog algoritma

This paper proposes a novel hybrid control of induction motor, based on the combination of the direct torque control DTC and the backstepping one, optimized by Genetic Algorithm (GA). First the basic evolution of DTC is explained, where the torque and stator flux are controlled by non linear hysteresis controllers which cause large ripple in motor torque at steady state operation. A Backstepping control is applied to overcome these problems, however the used parameters are often chosen arbitrarily, which may affect the controller quality. To find the best parameters, an optimization technique based on genetic algorithm is used. Also, in order to obtain accurate information about stator flux, torque and load torque, open loops estimators are used for this Backstepping control. At last, experimental results are presented in order to prove the efficiency of the above mentioned control technique.U ovom radu predstavljena je nova metoda hibridnog upravljanja indukcijskim motorom, bazirana na kombinaciji direktnog upravljanja momentom (DCT) i povratnokoračnog upravljanja, te optimizirana korištenjem genetičkog algoritma (GA). Prvo je objašnjena osnova razvoja DCT-a, gdje se momentom i tokom statora upravlja nelinearnim histereznim regulatorima što uzrokuje velike propade u momentu motora tijekom ravnotežnog rada. Povratnokoračno upravljanje se primijenjuje kako bi se uklonio ovaj problem, međutim korišteni parametri su najčešće proizvoljno odabrani što može utjecati na kvalitetu upravljanja. Kako bi se našli najbolji parametri koristi se tehnika optimizacije zasnovana na genetičkom algoritmu. Također kako bi se dobili točni podaci o toku statora, momentu i momentu opterećenja potrebni za povratnokoračno upravljanje koriste se estimatori u otvorenoj petlji. Na kraju su prikazani eksperimentalni rezultati kako bi se dokazala efikasnost navedene metode upravljanja

Boundedly rational expected utility theory

We build a satisficing model of choice under risk which embeds Expected Utility Theory (EUT) into a boundedly rational deliberation process. The decision maker accumulates evidence for and against alternative options by repeatedly sampling from her underlying set of EU preferences until the evidence favouring one option satisfies her desired level of confidence. Despite its EUT core, the model produces patterns of behaviour that violate standard EUT axioms, while at the same time capturing systematic relationships between choice probabilities, response times and confidence judgments, which are beyond the scope of theories that do not take deliberation into account

Ugađanje otpora rotora vektorski upravljanog indukcijskog motora korištenjem TS neizrazite logike

In this paper, we focus on the estimation of the rotor resistance to online tune the controllers in case of the Indirect Rotor Field Orientation Control (IRFOC) of Induction Machine (IM). The proposed method is based on the development of an adaptive Takagi-Sugeno (TS) fuzzy flux observer, described in a d-q synchronous rotating frame, to concurrently estimate the IM states and the rotor resistance variation. An investigation of the local pole placement is carried out in order to guarantee both the stability and specified observer dynamic performances. The observer\u27s gains design is based on the resolution of sufficient conditions driven into LMIs terms (Linear Matrix Inequalities). Simulation and experimentation are carried out to show the effectiveness of the proposed results.U ovom radu fokusiramo se na estimaciju otpora rotora za ugađanje parametera kontrolera tijekom rada indukcijskog motora (IM) upravljanog metodom indirektne kontrole orijentacije polja rotora (IRFOC). Predložena metoda je bazirana na razvoju adaptivnog Takagi-Sugeno (TS) neizrazitog obzervera toka, opisanog u d-q sinkronom rotacijskom okviru, kako bi se istovremeno estimirala stanja i varijacije otpora rotora IM-a. Provedeno je istraživanje lokalnog postavljanja polova kako bi se osigurala stabilnost i zadane dinamičke performanse obzervera. Dizajn pojačanja estimatora baziran je na rješenju dovoljnog broja uvjeta izraženih pomoću LMN izraza (linearne matrične nejednakosti). Simulacija i eksperimenti su provedeni kako bi se pokazala ispravnost predloženih rezultata

Boundedly rational expected utility theory

We build a satisficing model of choice under risk which embeds Expected Utility Theory (EUT) into a boundedly rational deliberation process. The decision maker accumulates evidence for and against alternative options by repeatedly sampling from her underlying set of EU preferences until the evidence favouring one option satisfies her desired level of confidence. Despite its EUT core, the model produces patterns of behaviour that violate standard EUT axioms, while at the same time capturing systematic relationships between choice probabilities, response times and confidence judgments, which are beyond the scope of theories that do not take deliberation into account

Roles of minerals (Sodium, Potassium, Calcium and Magnesium) in the prevention and management of high blood pressure

L’hypertension artérielle (HTA) est définie comme étant une pression artérielle systolique supérieure ou égale à 140 mm Hg et une pression diastolique supérieure ou égale à 90 mm Hg, chez un sujet sans complications particulières. L’implication du sodium dans l’augmentation des chiffres tensionnels est détaillée dans de nombreux ouvrages scientifiques dont la majorité rapporte qu’il est dangereux lorsqu’il est consommé en excès. Il provoque notamment la vasoconstriction, la rigidification des artères et accélère le vieillissement rénal. Cependant, les rôles des autres minéraux (calcium, magnésium et potassium) ne semblent pas être suffisamment considérés. Ainsi, il est nécessaire d’éclaircir l’impact de ces minéraux sur la prévention et la prise en charge de l’hypertension. Pour le potassium, plusieurs études ont démontré qu’un moindre apport en potassium, c’est-à-dire inférieur 3500 mg/j, augmenterait le risque de survenue d’une HTA alors qu’un apport situé entre 3500 et 4700 mg par jour permettrait de mettre en évidence l’effet hypotenseur du potassium, son effet est associé à la quantité de sodium. Plus l’apport en sodium est élevé plus le potassium a un pouvoir antihypertensif. Pour le calcium, son mécanisme d’action sur la pression artérielle n’est pas assez clair, mais les hypothèses scientifiques suggèrent que le calcium aurait une action vasodilatatrice par le fait qu’une diminution de la concentration calcique intracellulaire était en mesure de diminuer la pression artérielle. Cette hypothèse elle-même viendrait de l’action des inhibiteurs calciques qui dans leur mécanisme vont réduire le tonus musculaire par blocage des canaux calciques, accompagné d’un effet vasodilatateur. Pour le magnésium, des études ont montré son effet vasodilatateur. En effet, une diminution de la concentration en magnésium provoquerait une vasoconstriction et qu’à l’inverse, une augmentation de sa concentration favoriserait une vasodilatation. De plus, d’autres études ont montré que l’association entre ces différents minéraux était tout autant efficace pour réduire significativement les chiffres tensionnels. Un certain nombre de travaux de recherche à ce sujet montre clairement l’importance de considérer les niveaux en ces minéraux dans la prévention et la prise en charge de l’hypertension. Mots clés: hypertension artérielle, calcium, magnésium, potassium, sodiumHigh blood pressure is defined as a systolic blood pressure greater than or equal to 140 mm Hg and a diastolic pressure greater than or equal to 90 mm Hg in a subject with no particular complications. The involvement of sodium in the increase in blood pressure figures is detailed in many scientific publications, but what about other minerals. After the analysis carried out on various reviews, we were able to identify the effects of K, Ca and Mg on blood pressure. For potassium, several studies have shown that a lower potassium intake, i.e. less than 3500 mg/day, would increase the risk of an hypertension, while an intake between 3500 and 4700 mg per day would highlight the hypotensive effect of potassium, its effect is associated with the amount of sodium, the higher the sodium intake, the more potassium has an antihypertensive power. For calcium, its mechanism of action on blood pressure is still not so clear, but the scientists' hypothesis suggest that calcium has a vasodilatory action because a decrease in intracellular calcium concentration was able to reduce blood pressure. This hypothesis itself comes from the action of calcium inhibitors, which in their mechanism will reduce muscle tone by blocking calcium channels with a vasodilatory effect. For magnesium, studies have shown its vasodilatory effect. A decrease in magnesium concentration would cause vasoconstriction and conversely an increase in its concentration would promote vasodilation. In addition, other studies have shown that the association between these different minerals is equally effective in significantly reducing blood pressure levels. Keywords: hypertension, calcium, magnesium, potassium, sodiu

Coordination and Sophistication

How coordination can be achieved in isolated, one-shot interactions without com-munication and in the absence of focal points is a long-standing question in game theory. We show that a cost-benefit approach to reasoning in strategic settings delivers sharp theoretical predictions that address this central question. In particular, our model predicts that, for a large class of individual reasoning processes, coordination in some canonical games is more likely to arise when players perceive heterogeneity in their cognitive abilities, rather than homogeneity. In addition, and perhaps contrary to common perception, it is not necessarily the case that being of higher cognitive sophistication is beneficial to the agent: in some coordination games, the opposite is true. We show that subjects’ behavior in a laboratory experiment is consistent with the predictions of this model, and reject alternative coordination mechanisms. Overall, the empirical results strongly support our model

Diagnosis of learning difficulties of plate tectonics concepts among secondary school students using: Focus group, nominal group, and questionnaire

The teaching of geology or earth sciences occupies an important place in the life and earth sciences programs of the secondary cycle in Morocco. The theory of plate tectonics is the conceptual model that allows an understanding of most of the dynamic processes of the Earth. Our work aims to diagnose the difficulties related to the learning of the concepts related to plate tectonics by following a hybrid methodology of three techniques, namely: focus group, nominal group, and questionnaire. The results obtained allowed us to identify difficulties in the educational act in its different facets, whether epistemological, pedagogical, didactic, curricular, and logistical. These difficulties should be taken into consideration by the different actors in the educational process, in order to guarantee the successful learning of this discipline

Boundedly Rational Expected Utility Theory

We build a satisficing model of probabilistic choice under risk which embeds Expected Utility Theory (EUT) into a boundedly rational deliberation process. The decision maker accumulates evidence for and against alternative options by repeatedly sampling from her underlying set of EU preferences until the evidence favouring one option satisfies her desired level of confidence. Notwithstanding its EUT core, the model produces patterns of behaviour that violate standard axioms, while at the same time capturing the systematic relationship between choice probabilities, response times and confidence judgments, which is beyond the scope of theories that do not take deliberation into account