Tayloring Brazil: a system dynamics model for monetary policy feedback

The thesis introduces a system dynamics Taylor rule model of new Keynesian nature for monetary policy feedback in Brazil. The nonlinear Taylor rule for interest rate changes con-siders gaps and dynamics of GDP growth and inflation. The model closely tracks the 2004 to 2011 business cycle and outlines the endogenous feedback between the real interest rate, GDP growth and inflation. The model identifies a high degree of endogenous feedback for monetary policy and inflation, while GDP growth remains highly exposed to exogenous eco-nomic conditions. The results also show that the majority of the monetary policy moves during the sample period was related to GDP growth, despite higher coefficients of inflation parameters in the Taylor rule. This observation challenges the intuition that inflation target-ing leads to a dominance of monetary policy moves with respect to inflation. Furthermore, the results suggest that backward looking price-setting with respect to GDP growth has been the dominant driver of inflation. Moreover, simulation exercises highlight the effects of the new BCB strategy initiated in August 2011 and also consider recession and inflation avoid-ance versions of the Taylor rule. In methodological terms, the Taylor rule model highlights the advantages of system dynamics with respect to nonlinear policies and to the stock-and-flow approach. In total, the strong historical fit and some counterintuitive observations of the Taylor rule model call for an application of the model to other economies.

O que norteia a escolha de professores de língua estrangeira por diferentes tipos de feedback corretivo

O presente estudo foi desenvolvido com o objetivo de investigar, através de uma perspectiva sociocultural, o que norteia a escolha de diferentes tipos de feedback corretivo por professores de língua estrangeira (LE) ao corrigir a fala de seus alunos. A pesquisa foi realizada em um curso particular de idiomas no sul do Brasil que segue os princípios da abordagem comunicativa, tendo cinco professores como participantes. Este trabalho foi realizado através da observação do comportamento corretivo dos professores atuando com seus próprios alunos durante atividades com foco na forma. Tais atividades foram gravadas em vídeo e, logo após a gravação, foram comentadas pelos professores durante entrevistas com a pesquisadora, as quais também foram gravadas em vídeo. Houve uma terceira gravação que consistiu em uma entrevista entre a pesquisadora e cada professor participante para conversarem sobre as percepções dos professores a respeito de tratamento corretivo e diferentes tipos de feedback. A análise das transcrições das gravações resultou em um levantamento e uma descrição das escolhas corretivas de cada professor individualmente e uma descrição do padrão de comportamento quanto à opção por feedback reformulador e/ou feedback elicitativo. Verifiquei que os cinco professores estudados - mesmo tendo experiências, tempo de prática e formação diferentes - consideram principalmente os seguintes fatores quando decidem optar por tipos de feedback: como julgam que o aluno está se sentindo no momento, como vêem a personalidade do aluno e como julgam ser a capacidade lingüística e a capacidade emocional do aluno.

Global stabilizing feedback law for a problem of biological control of mosquito-borne diseases

The control of the spread of dengue fever by introduction of the intracellular parasitic bacterium Wolbachia in populations of the vector Aedes aegypti, is presently one of the most promising tools for eliminating dengue, in the absence of an efficient vaccine. The success of this operation requires locally careful planning to determine the adequate number of mosquitoes carrying the Wolbachia parasite that need to be introduced into the natural population. The latter are expected to eventually replace the Wolbachia-free population and guarantee permanent protection against the transmission of dengue to human. In this paper, we propose and analyze a model describing the fundamental aspects of the competition between mosquitoes carrying Wolbachia and mosquitoes free of the parasite. We then introduce a simple feedback control law to synthesize an introduction protocol, and prove that the population is guaranteed to converge to a stable equilibrium where the totality of mosquitoes carry Wolbachia. The techniques are based on the theory of monotone control systems, as developed after Angeli and Sontag. Due to bistability, the considered input-output system has multivalued static characteristics, but the existing results are unable to prove almost-global stabilization, and ad hoc analysis has to be conducted.

WalkNRide: contextualising feedback in physical activity trackers

Increasing levels of sedentarism and obesity, along with advances in sensor technologies have instigated a market for wearable activity trackers, electronic devices that sense users’ physical activity levels with the goals of self-monitoring and behaviour change. Nowadays, activity trackers are one of the most desirable technologies, making up for a market of over $230 million in 2013. However, despite the spike of users’ interest, activity trackers have been shown to lose their appeal over time, with a recent survey suggesting that one out of three users discard the tracker in the course of the first six months of use. The question we pose is: how can we design activity tracker so that users’ interests is sustained over the long term? Our design approach focuses on contextualising physical activity. We do this through sensing users’ locations and activities (such as being still, walking or commuting through a car, bus or other means) and thus providing innovative ways of presenting feedback on users. This thesis presents the design and evaluation of WalkNRide, a physical activity tracker for Google Android. Through a longitudinal field study of WalkNRide, we attempt to inquire into the factors that drive the adoption (or non-adoption) of the tool as well as the ways in which the use of the tool contributes towards habit formation.

Motivating sustainable goal choices and providing effective feedback

Overconsumption of natural resources and the associated environmental hazards are one of today’s most pressing global issues. In the western world, individual consumption in homes and workplaces is a key contributor to this problem. Reflecting the importance of individual action in this domain, this thesis focuses on studying and influencing choices related to sustainability and energy consumption made by people in their daily lives. There are three main components to this work. Firstly, this thesis asserts that people frequently make ineffective consumption reduction goal choices and attempts to understand the rationale for these poor choices by fitting them to goalsetting theory, an established theoretical model of behavior change. Secondly, it presents two approaches that attempt to influence goal choice towards more effective targets, one of which deals with mechanisms for goal priming and the other of which explores the idea that carefully designed toys can exert influence on children’s long term consumption behavior patterns. The final section of this thesis deals with the design of feedback to support the performance of environmentally sound activities. Key contributions surrounding goals include the finding that people choose easy sustainable goals despite immediate feedback as to their ineffectiveness and the discussion and study of goal priming mechanisms that can influence this choice process. Contributions within the design of value instilling toys include a theoretically grounded framework for the design of such toys and a completed and tested prototype toy. Finally, contributions in designing effective and engaging energy consumption feedback include the finding that negative feedback is best presented verbally compared with visually and this is exemplified and presented within a working feedback system. The discussions, concepts, prototypes and empirical findings presented in this work will be useful for both environmental psychologists and for HCI researchers studying eco-feedback.

Exploring the dimensions of eco-feedback in the wild

Worldwide reports about energy usage have noted the importance of the domestic energy consumption sector in the worldwide scenario. This fact motivated and supported the birth and spread of the so-called eco-feedback devices. Such devices provide information about individual or group energy consumption behavior with the goal of reducing the impact in the environment. Motivated by the body of work which questions the long term effectiveness of eco-feedback systems, this thesis focus on evaluating in-the-wild the long term usage of eco-feedback systems. We have conducted five long term studies with different eco-feedback systems designed to evaluate different dimensions in the design of eco-feedback plus two more focused short term studies aimed at studying concrete approaches. Our summary reports on the fact that the there is a novelty effect associated with ecofeedback systems in which the usage of these devices declines significantly after a month. We did not found evidence that the novelty effect is related to location or the type of information represented, nor that the decrease in the eco-feedback usage could lead to the consumption relapsing to values previous to the introduction of the eco-feedback. Our work has also generated other contributions related to the positioning of the feedback, using metaphors for representing the consumption and presenting information about the source of the energy in the feedback.

Controle feedback de nível baseado em sensor de imagem aplicado ao equipamento misturador-decantador à inversão de fases (MDIF®)

The treatment of wastewaters contaminated with oil is of great practical interest and it is fundamental in environmental issues. A relevant process, which has been studied on continuous treatment of contaminated water with oil, is the equipment denominated MDIF® (a mixer-settler based on phase inversion). An important variable during the operation of MDIF® is the water-solvent interface level in the separation section. The control of this level is essential both to avoid the dragging of the solvent during the water removal and improve the extraction efficiency of the oil by the solvent. The measurement of oil-water interface level (in line) is still a hard task. There are few sensors able to measure oil-water interface level in a reliable way. In the case of lab scale systems, there are no interface sensors with compatible dimensions. The objective of this work was to implement a level control system to the organic solvent/water interface level on the equipment MDIF®. The detection of the interface level is based on the acquisition and treatment of images obtained dynamically through a standard camera (webcam). The control strategy was developed to operate in feedback mode, where the level measure obtained by image detection is compared to the desired level and an action is taken on a control valve according to an implemented PID law. A control and data acquisition program was developed in Fortran to accomplish the following tasks: image acquisition; water-solvent interface identification; to perform decisions and send control signals; and to record data in files. Some experimental runs in open-loop were carried out using the MDIF® and random pulse disturbances were applied on the input variable (water outlet flow). The responses of interface level permitted the process identification by transfer models. From these models, the parameters for a PID controller were tuned by direct synthesis and tests in closed-loop were performed. Preliminary results for the feedback loop demonstrated that the sensor and the control strategy developed in this work were suitable for the control of organic solvent-water interface level

Interação em sala de aula de língua inglesa: o feedback como estratégia do desempenho assistido

This dissertation aims at characterizing the practices as well as the effects of a teacher s feedback in oral conversation interaction with students in an English Language classroom at a Primary School, 6th Grade in Açu/RN, Brazil. Therefore, this study is based on Vygotsky s (1975) and Bruner´s (1976) researches, which state that the learning process is constructed through interaction between a more experienced individual (teacher, parents and friends) and a learner who plays an active role, a re-constructor of knowledge. It is also based on Ur´s (2006) and Brookhart s (2008) studies (among other authors in Applied Linguistic) who defend that the feedback process needs to be evaluative and formative since it sets interfaces with both students autonomy and learning improvement. Our study is based on qualitative, quantitative and interpretive researches, whose natural environment (the classroom) is a direct source of data generated in this research through field observations/note-taking as well as through the transcriptions of five English classes audio taped. This study shows the following results: the teacher still seems to accept the patterns of interaction in the classroom that correspond to the IRE process (Initiation, Response, Evaluation) in behaviorist patterns: (1) he speaks and determines the turns of speech; (2) the teacher asks more questions and directs the activities most of the time; (3) the teacher´s feedback presents the following types: questioning, modeling, repeated response, praise, depreciation, positive/negative and sarcasm feedback, whose functions are to assess students' performance based on the rightness and wrongness of their responses. Thus, this implies to state that the feedback does not seem to help students improvement in terms of acquiring knowledge because of its normative effects/roles. Therefore, it is the teacher´s role to give evaluative and formative feedback to a student so that he/she should advance in the learning of the language and in the construction of knowledge

Concurrent nociceptive stimulation impairs the anxiolytic effect of midazolam injected into the periaqueductal gray in mice

This study investigated whether the opportunity to avoid or escape the open arms of an elevated plus-maze (EPM) affects the antinociceptive response observed when mice are subjected to open arm confinement. Furthermore, in order to better characterize the relationship between emotion and antinociception in the EPM, we examined the behavioral effects of midazolam injection into the midbrain periaqueductal gray matter (PAG). As our main aim was to evaluate the relevance of different levels of approach-avoid conflict (i.e. The presence of open and closed arms) to maze-induced antinociception, mice were exposed to one of three types of EPM-a standard EPM (sEPM), an open EPM (oEPM: four open arms) or, as a control condition, an enclosed EPM (eEPM: four enclosed arms). Nociception was assessed using the formalin test. Twenty minutes after formalin injection (50 mu l, 2.5% formalin) into the dorsal right hind paw, mice received an intra-PAG injection of saline or midazolam (10-20 nmol). Five minutes later, they were individually exposed to one of the mazes for 10 min (25-35 min after formalin injection). Videotapes of the test sessions were scored for a variety of behavioral measures including time spent licking the formalin-injected paw. To examine whether the effects of midazolam on anxiety-like behavior may have been influenced by concurrent nociceptive stimulation (i.e. formalin pretreatment), naive mice were submitted to a similar procedure to that described above for the sEPM test but without formalin pretreatment. Results showed that mice exposed to the oEPM spent significantly less time licking the injected paw compared to groups exposed to either the sEPM or eEPM. Although exposure to the sEPM induced anxiety-like behaviors (i.e. open arm avoidance), it did not result in antinociception. Intra-PAG infusions of midazolam failed to block oEPM-induced antinociception or to alter sEPM-induced anxiety in mice that had received formalin injection. However, under normal test conditions (i.e. in the absence of formalin-induced nociceptive stimulation), intra-PAG midazolam produced clear anti-anxiety effects in mice exposed to the sEPM. Findings are discussed in terms of different emotional states induced by the oEPM and sEPM and the influence of concurrent nociceptive stimulation on the anti-anxiety effect of intra-PAG midazolam. (c) 2005 Elsevier B.V. All rights reserved.

A influência do feedback verbal na cooperação em crianças

Human cooperation is a hallmark of this species due to its wide extension to genetically unrelated individuals and complex division of labor. It is considered an evolutionary puzzle, because the theory of evolution by natural selection predicts that self-interested individuals tend to be selected. Different theories have been proposed to explain the evolution of cooperation, which the most important are kin selection and reciprocal altruism. Considering the evolutionary continuity between species, humans and other primates have several common traits that help to promote cooperation between individuals of these species. Two features, however, seem to be particularly humans: inequality aversion and preferences in relation to others. Although human cooperation is not necessarily related to morality, cooperative traits are the basis for moral tendencies. The development of human morality is a combination of early prosocial tendencies, cooperative skills displayed at different ages, social learning and cultural transmission of norms. The social stimulus seems to be particularly important in promoting cooperative behavior in children and adults. In order to study the influence of social stimuli, as verbal feedback, on children cooperation, a study was conducted with children in a public goods game. 407 children from public schools in Natal / RN, divided into 21 groups, between six and nine years, participated in eight rounds of this game. After each round, seven groups received praise for larger donations, seven groups have been criticized by smaller donations, and the other seven received no comment. Children cooperated more when criticized, without significant differences between sexes, although young children have cooperated more negative than older children. The results are likely related to the anticipation and avoidance of punishment associated with the feedback (although this did not occur), and greater sensitivity to the authority in younger children. Nevertheless, the cooperation decreased in all groups until the last day of play. The results suggest an early sensitivity to moral punishment, whose role in the maintenance of social relations must have been important in the evolution of cooperation in humans

LMI-based algorithm for strictly positive real systems with static output feedback

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parameter-dependent Lyapunov functions for state-derivative feedback control in polytopic linear systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Robust State-Derivative Feedback LMI-Based Designs for Linear Descriptor Systems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)