Dissertations / Theses on the topic 'Terrain following'

There is a large number of measurement techniques that is used for a surface inspection and a characterization of different types of materials. One of these techniques is a contact potential difference (CPD) scanning technique. In this project a non-vibrating contact potential difference (nvCPD) method is utilized to measure a work function and a topographical structure of a sample surface. A sample is mounted on a spindle that rotates at high speed. A nvCPD sensor detects work-function variations during movement above the sample surface. There are certain factors that create difficulties during the measurement process. A nonplanar sample surface, the spindle wobble and an incline of a mounted sample impede the safe (without impacting the surface) scanning at a close distance. The goal of this thesis was to implement a height sensor as a feedback device to dynamically control and adjust a CPD sensor flying height. Since a CPD signal is inversely proportional to the flying height, minimization of this height will enhance the signal magnitude, the signal-to-noise ratio and the resolution of measurements.

Planning algorithms have applications in many fields such as robotics, logistics, and more.Planning for terrain following flights can be to utilize features of the terrain to minimizethe risk of detection. The similar problem of terrain avoidance is applicable to planningthe movement for survey or search vehicles, where low and fixed altitude may be important.Common problems that arise when planning for terrain following flights is that the dynamics ofthe vehicle are difficult to model, the state space is only represented in an approximate mannerand detailed calculations of the subject are computationally expensive. This work presents aplanning algorithm for the vertical component of terrain following flight paths using methods ofenergy, where the path itself is modelled as an elastic band deformed by virtual forces to followthe terrain. Using linear internal equations of motion for the elastic band, the computationalcomplexity can be kept low. Similar ideas have been used for planning algorithms in otherworks, but novel to the method presented here is that complicated limitations to the dynamicsof the vehicle can be treated in an effective manner. This is achieved by an adaptive linearcombination of different models for the internal elastic forces.

There are many applications for which small unmanned aerial vehicles (SUAVs) are well suited, including surveillance, reconnaissance, search and rescue, convoy support, and short-range low-altitude perimeter patrol missions. As technologies for microcontrollers and small sensors have improved, so have the capabilities of SUAVs. These improvements in SUAV performance increase the possibility for hazardous missions through mountainous and urban terrain in the successful completion of many of these missions. The focus of this research was on remote terrain navigation and the issues faced when dealing with limited onboard processing and limited payload and power capabilities. Additional challenges associated with canyon and urban navigation missions included reactive path following, sensor noise, and flight test design and execution. The main challenge was for an SUAV to successfully navigate through a mountainous canyon by reactively altering its own preplanned path to avoid canyon walls and other stationary obstacles. A robust path following method for SUAVs that uses a vector field approach to track functionally curved paths is presented along with flight test results. In these results, the average tracking error for an SUAV following a variety of curved paths is 3.4~m for amplitudes ranging between 10 and 100~m and spatial periods between 125 and 500~m. Additionally, a reactive path following method is presented that allows a UAV to continually offset or bias its planned path as distance information from the left and right ranging sensors is computed. This allows the UAV to to center itself between potential hazards even with imperfect waypoint path planning. Flight results of an SUAV reactively navigating through mountainous canyons experimentally verify the feasibility of this approach. In a flight test through Goshen Canyon in central Utah, an SUAV biased its planned path by 3 to 10~m to the right as it flew to center itself through the canyon and avoid the possibility of crashing into a canyon wall.

There are occasions when it is preferable that an aircraft flies asclose to the ground as possible. It is difficult for a pilot to predict the topography when he cannot see beyond the next hill, and this makes it hard for him to find the optimal flight trajectory. With the help of a terrain database in the aircraft, the forthcoming topography can be found in advance and a flight trajectory can be calculated in real-time. The main goal is to find an optimal control sequence to be used by the autopilot. The optimization algorithm, which is created for finding the optimal control sequence, has to be run often and therefore, it has to be fast.

This thesis presents a terrain following algorithm based on Model Predictive Control which is a promising and robust way of solving the optimization problem. By using trajectory optimization, a trajectory which follows the terrain very good is found for the non-linear model of the aircraft.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.
Includes bibliographical references (p. 123-125).
This thesis presents the design and implementation of a model predictive control based trajectory optimization method for Nap-of-the-Earth (NOE) flight. A NOE trajectory reference is generated over a subspace of the terrain. It is then inserted into the cost function and the resulting trajectory tracking error term is weighted for more precise longitudinal tracking than lateral tracking through the introduction of the TF/TA ratio. The TF/TA ratio, control effort penalties and MPC prediction horizon are tuned for this application via simulation and eigenvalue analysis for stability and performance. Steps are taken to reduce complexity in the optimization problem including perturbational linearization in the prediction model generation and the use of control basis functions which are analyzed for their trade-off between approximation of the optimal cost/solution and reduction of the optimization complexity. Obstacle avoidance including preclusion of ground collision is accomplished through the establishment of hard state constraints. These state constraints create a 'safe envelope' within which the optimal trajectory can be found. Results over a variety of sample terrains are provided to investigate the sensitivity of tracking performance to nominal velocities. The mission objective of low altitude and high speed was met satisfactorily without terrain or obstacle collision, however, methods to preclude or deal with infeasibility must be investigated as terrain severity (measured by commanded flight path angle) is increased past 30 degrees or speed is increased to and past 30 knots.
by Tiffany Rae Lapp.
S.M.

In the present work, a study is proposed about the applicability of a predictive controller to be used to control the longitudinal mode of an aircraft. The objective is to evaluate the performance of such control approach applied to a terrain following task, verifying the tracking suitability while respecting physical constraints to which the aircraft is subjected to. As examples, control surfaces range limitations, restrictions for the available thrust as well as other variables such as the angle of attack, velocity, pitch rate and the altitude itself. A fighter aircraft simplified model was used for the longitudinal movement to perform the simulations. The predictive control approach used was based on a linear prediction model described in the state space. Therefore, it was necessary to linearize the aircraft dynamic around an equilibrium point previously chosen. Two scenarios were evaluated for the same terrain profile. The first considered the simulation with the system nominal constraints. The second scenario covered an elevator actuator failure, in order to analyze the suitability of such controller when dealing with the online imposed constraints. The advantages of the predictive control methodology were evident based on the results for both scenarios, where an adequate terrain profile tracking was observed and, at the same time, the imposed restrictions were enforced in the performed simulations.

This thesis makes a number of new contributions to control and sensing for unmanned vehicles. I begin by developing a non-linear simulation of a small unmanned helicopter and then proceed to develop new algorithms for control and sensing using the simulation. The work is field-tested in successful flight trials of biologically inspired vision and neural network control for an unstable rotorcraft. The techniques are more robust and more easily implemented on a small flying vehicle than previously attempted methods.¶ Experiments from biology suggest that the sensing of image motion or optic flow in insects provides a means of determining the range to obstacles and terrain. This biologically inspired approach is applied to control of height in a helicopter, leading to the World’s first optic flow based terrain following controller for an unmanned helicopter in forward flight. Another novel optic flow based controller is developed for the control of velocity in hover. Using the measurements of height from other sensors, optic flow is used to provide a measure of the helicopters lateral and longitudinal velocities relative to the ground plane. Feedback of these velocity measurements enables automated hover with a drift of only a few cm per second, which is sufficient to allow a helicopter to land autonomously in gusty conditions with no absolute measurement of position.¶ New techniques for sensor fusion using Extended Kalman Filtering are developed to estimate attitude and velocity from noisy inertial sensors and optic flow measurements. However, such control and sensor fusion techniques can be computationally intensive, rendering them difficult or impossible to implement on a small unmanned vehicle due to limitations on computing resources. Since neural networks can perform these functions with minimal computing hardware, a new technique of control using neural networks is presented. First a hybrid plant model consisting of exactly known dynamics is combined with a black-box representation of the unknown dynamics. Simulated trajectories are then calculated for the plant using an optimal controller. Finally, a neural network is trained to mimic the optimal controller. Flight test results of control of the heave dynamics of a helicopter confirm the neural network controller’s ability to operate in high disturbance conditions and suggest that the neural network outperforms a PD controller. Sensor fusion and control of the lateral and longitudinal dynamics of the helicopter are also shown to be easily achieved using computationally modest neural networks.

Terrestrial robots must be capable of negotiating rough terrain if they are to become autonomous outside of the lab. Although the control mechanism offered by wheels is attractive in its simplicity, any wheeled system is confined to relatively flat terrain. Wheels will also only ever be useful for rolling, while limbs observed in nature are highly multimodal. The robust locomotive utility of legs is evidenced by the many animals that walk, run, jump, swim, and climb in a world full of challenging terrain. On the other hand, legs with multiple degrees of freedom (DoF) require much more complex control and precise sensing than wheels. Legged robotic systems are easily hampered by sensor noise and bulky control loops that prohibit the high-speed adaptation to external perturbations necessary for dynamic stability in real time. Low sensor bandwidth can limit the system’s reaction time to external perturbations. It is also often necessary to filter sensor data, which introduces significant delays in the control loop. In addition, state estimation is often relied upon in order to compute active stabilizing responses. State estimation requires accurate sensor data, often involving filtering, and can involve additional nontrivial computation such as the pseudo-inversion of fullbody Jacobians. This perception portion of the control burden is all incurred before a response can be planned and executed. These delays can prevent a system from executing a corrective response before instability leads to failure. The present work presents an approach to legged system design and control that reduces both the perception and planning aspects of the online control burden. A commonly accepted design goal in robotics is to accomplish a task with the fewest possible DoF in order to tighten the control loop and avoid the curse of dimensionality. However, animals control many DoF in a manner that adapts to external perturbations faster than can be explained by efferent neural control. The passive mechanics of segmented animal limbs are capable of rejecting unexpected disturbances without the supervision of an active controller. By simulating biomimetic limbs, we can learn more about this preflexive response, how the properties of segmented biological limbs foster self-stable passive mechanics, and how the control burden can be mitigated in robotic legged systems. The contribution of this body of work is to reduce the control burden of legged locomotion for robots by drawing on self-stabilizing mechanical design and control principles observed in animal locomotion. To that end, minimal templates such as Sensory-Coupled Action Switching Modules (SCASM), Central Pattern Generators (CPGs), and the Spring-Loaded Inverted Pendulum (SLIP) model are used to learn more about the essential components of legged locomotion. The motivation behind this work lies largely in the study of how internal, predictive models and the intrinsic mechanical properties of biological limbs help animals self-stabilize in real time. Robotic systems have already begun to demonstrate the benefits of these biological design primitives in an engineering context, such as reduced cost of transportation and an immediate mechanical response that does not need to wait for sensor feedback or planning. The original research presented here explores the extent to which these principles can be utilized in order to encourage stable legged locomotion over uneven terrain with as little sensory information as possible. A method for generating feedforward, terrain-adaptive control primitives based on a compliant limb architecture is developed. Offline analysis of system dynamics is used to develop clock-driven patterns of leg stiffness and attack angle control during late swing with which passive stance phase dynamics will produce the desired apex height and stride period to within 0.1 mm and 50 μs, respectively. A feedforward method of energy modulation is incorporated that regulates velocity to within 10−5 m/s. Preservation of a constant stride period eliminates the need for detection of the apex event. Precise predictive controls based on thorough offline dynamic modeling reduce the system’s reliance on state and environmental data, even in rough terrain. These offline models of system dynamics are used to generate a controller that predicts the dynamics of running over uneven terrain using an internal clock signal. Real-time state estimation is a non-trivial bottleneck in the control of mobile systems, legged and wheeled alike. The present work significantly reduces this burden by generating predictive models that eliminate the need for state estimation within the control loop, even in the presence of damping. The resulting system achieves not only self-stable legged running, but direct control of height, speed, and stride period without inertial sensing or force feedback. Through this work, the controller dependency on accurate and rapid sensing of the body height and velocity, apex event, and ground variation was eliminated. This was done by harnessing physics-based models of leg dynamics, used to generate predictive controls that exploit the passive mechanics of the compliant limb to their full potential. While no real world system is entirely deterministic, such a predictive model may serve as the base layer for a lightweight control architecture capable of stable robotic limb control, as in animal locomotion.

Dans le jargon de l’océanographie physique, un «overflow » est une masse d’eau dense, formée sur un plateau continental ou dans une mer marginale, qui rejoint l’océan ouvert en s’écoulant par-delà de fortes contraintes topographiques telles que d’étroits détroits, des seuils ou des talus continentaux particulièrement pentus. Ces processus d'overflow jouent un rôle important en distribuant les flux de chaleur et de sel dans l'océan, car ils alimentent les courants profonds et la plus grande partie des eaux profondes de l'océan global. Une représentation irréaliste de ces processus dans les modèles peut avoir un impact sur leur aptitude à simuler d'autres aspects majeurs de la circulation océanique globale.Représenter de manière réaliste les overflows est encore un défi en modélisation numérique de l’océan. Cette thèse étudie ce problème en utilisant le modèle de la circulation générale océanique NEMO avec une configuration régionale de l’overflow du détroit du Danemark (Denmark Strait Overflow, DSO) avec des résolutions dites eddy-permitting/resolving (permettant la génération de turbulence de mésoéchelle). Dans ce travail je propose d’abord une définition du DSO pour pouvoir caractériser les masses d'eaux qui lui sont associées et pour mettre en évidence et quantifier les principaux défauts de représentation du DSO rencontrés dans une simulation de référence réalisée avec les paramètres standards couramment utilisés dans les configurations globales de NEMO (configurations Drakkar).Grâce à cette définition, j’ai pu quantifier l'impact d'un grand nombre de paramètres du modèle sur la représentation du DSO avec des résolutions allant de l'eddy-permitting (1/12°) à l'eddy-resolving (1/60°). Cette étude, qui a nécessité un grand nombre de simulations de sensibilité, a été faite avec le système de coordonnée verticale classique utilisé dans NEMO, qui est la coordonnée géopotentielle z.Les améliorations les plus importants ont été trouvées en augmentant la résolution verticale et horizontale de façon cohérente. Mes résultats ont cependant montrés que la plupart des paramètres du modèle ont un impact très faible sur la représentation finale du DSO. En particulier, nous avons trouvé qu'augmenter la résolution verticale sans utiliser une résolution horizontale cohérente détériore la solution. La principale raison est que la paramétrisation EVD, représentant la convection libre forcée par une instabilité statique de la colonne d’eau, propage la veine de fluide en direction de la pente de la grille, et non de la pente de la topographie, ce qui induit une trop forte dilution des propriétés de l’overflow. Une très haute résolution horizontale et verticale (1/60° et 300 niveaux) permet de résoudre la couche d'Ekman de fond et de maintenir l'EVD localisé au fond, limitant ainsi la dilution de la veine d’eau dense.J’ai ensuite étudié la représentation du DSO dans un système de coordonnée hybride combinant une coordonnée suivant-le-terrain (s) avec la coordonnée géopotentielle (z). Les améliorations obtenues dans la représentation du DSO sont remarquables et pour une faible augmentation du coût de calcul. Finalement, nous proposons un système de coordonnée verticale mixte s-z qui consiste en une implémentation locale de la coordonnée s à l’intérieur de la grille du modèle en coordonnée z, limité à la région où le DSO se produit. Cette implémentation locale minimise les effets des erreurs du gradient de pression liés à ce type de coordonnée, fait une connexion lisse avec la coordonnée z, et n'introduit pas de coûts de calcul démesurés. L'amélioration de la représentation du DSO est encore très importante.Ce travail souligne l'importance d’adapter le système de coordonnée verticale aux processus physiques les plus pertinents. Un défi de la modélisation serait d'avoir un système de coordonnée verticale qui est localement adapté aux processus océaniques dominants
Overflows play an important role distributing the heat and salt fluxes in the ocean, feeding deep boundary currents and most of the world ocean deep waters. Therefore, an unrealistic representation of overflows in global models may have impacts over many aspects of the simulated state of the ocean.To achieve a realistic representation of overflows is still a challenge for ocean modelling. This work addresses this problem using the community ocean general circulation model NEMO with a regional configuration of the Denmark Strait Overflow (DSO) at eddying resolutions. This work first proposes a definition of the DSO in order to characterize its associated water masses and to find the main caveats in a control simulation that uses the most standard parameters of the commonly used global configurations of NEMO (e.g. Drakkar configurations).Thanks to this definition we then study the impacts on the DSO of a large number of model parameters through a range of eddy-permitting to eddy-resolving resolutions (e.g. 1/12° and 1/60°) in the classic z-coordinate system used in NEMO. Main findings were found increasing the horizontal and vertical resolution, but most model parameters have no significant impacts. In particular it was found that increasing vertical resolution without using a coherent horizontal resolution degrades the solution. The main reason is the EVD parameterisation that propagates the dense vein of fluid along a grid-slope, instead the topographic slope. Coherent and very high resolution both in the horizontal and in the vertical is needed in order to resolve Ekman bottom boundary layer dynamics and keep the EVD localized to the very bottom.We also study the representation of the DSO with a hybrid terrain-following (s) and geopotential (z) coordinate system and obtained considerable improvements for a relatively small increase in computational cost. Finally, we propose a mixed s-z vertical coordinate that relies on a local implementation of s-coordinates within the z-coordinate model, limited to the area where DSO waters are produced. This local implementation is such that it minimizes the effects of pressure gradient errors linked to this type of coordinate, smoothly connects to the global z-coordinate, and does not add any significant computational cost. The improvement of the DSO is found to be drastic.This work emphasizes the utility of adapting the vertical coordinate system to the main physical problem. A modeling challenge would be to have a vertical coordinate system that is locally adapted to the most critical ocean process

La chirurgie thoracique est une chirurgie majeure, pourvoyeuse de complications postopératoires. La question de l’évaluation et de la préparation est centrale afin d’optimiser l’opérabilité et de limiter les répercussions liées à la résection pulmonaire. L’objectif de ce travail a été d’étudier les facteurs fonctionnels influençant la prise en charge chirurgicale de patients souffrant de cancer bronchique non à petites cellules. Nous avons vu en première partie l’intérêt des tests de terrain dans l’évaluation à l’effort. Nous avons effectué une méta-analyse sur le test de montée d’escaliers et conclu à son caractère prédictif de complications, avec un seuil de risque évalué à 10 mètres. Dans cette même partie, nous avons également développé une étude portant sur deux autres tests : le test de lever de chaise et le test stepper de 6 minutes. Nous avons conclu au caractère prédictif de complications de ces deux tests, avec un seuil optimal estimé à 141 steps et à 20 levers de chaise. Dans un second temps, nous avons orienté notre travail sur l’intérêt de la réhabilitation préopératoire chez les opérés par une voie d’abord mini-invasive. Nous observons dans cette étude que les patients bénéficiant d’une réhabilitation préopératoire ont des complications moins nombreuses et moins sévères que ceux qui n’en bénéficient pas, selon la classification de Clavien-Dindo. En dernière partie nous avons tenté de déterminer l’intérêt des tests de terrain dans l’accès à la réhabilitation. Nous observons que la fréquence cardiaque à la fin du test de lever de chaise ainsi que le nombre de levers et de pas au test stepper, sont liés de façon modérée à la fréquence cardiaque et à la puissance au seuil ventilatoire. Les tests de terrain pourraient être une alternative intéressante dans la prescription des paramètres de réentrainement à l’effort
Thoracic surgery is a major surgery, leading to postoperative complications. Assessment and preparation is central to optimize operability and to limit the impact of lung resection. The objective of this work was to study the functional factors influencing the surgical management of patients with non-small cell lung cancer. We saw in the first part the value of field tests in stress assessment. We performed a meta-analysis on the stair climbing test and concluded that it was predictive of complications, with a risk threshold assessed at 10 meters. In this same part, we also developed a study on two other tests: the sit to stand test and the 6-minute stepper test. We concluded that these two tests were predictive of complications, with an optimal threshold estimated at 141 steps and 20 chair lifts. Secondly, we focused our work on the benefit of preoperative rehabilitation in patients operated on by a minimally invasive approach. We observe in this study that patients undergoing preoperative rehabilitation have fewer and less severe complications than those who do not, according to the Clavien-Dindo classification. In the last part we tried to determine the value of field tests in access to rehabilitation. We observe that the heart rate at the end of the chair-lift test, as well as the number of lifts and steps in the stepper test, are moderately related to heart rate and power at the ventilatory threshold. Field tests could be an interesting alternative in prescribing the parameters of exercise training

The overall objective of the study was to analyse the Forest Dwelling Systems in the Terra Firme and Várzea communities and to investigate the conditions under which the different activities are allocated across households. In this study, the Farming System Approach facilitates a holistic examination of the Forest Dwelling Household System. This study broadly analyses the importance of natural products and their role as consumption and as goods for cash income for forest dwellers. By focusing on the functions of those products, their role within the Forest Dweller System must be examined. There have been identified differences between the Terra Firme (upland) and Várzea (floodplain) ecosystems management and production systems that are still ignored by decision makers. The study area was identified based on certain criteria: a) accessibility to the area (field support), b) availability of the forest production and, c) ecosystem (Terra Firme and Várzea communities). The survey was conducted in one community at the Terra Firme region (Itacoã) and in three communities at the Várzea region (Monte Tabor, Nova Santa Cruz, Manoel Carneiro). In selecting the households, the dependence on extraction of forest resources as the principal source of income was used as the major criteria, and part-time households were excluded from the studies. In order to obtain data on the structure of the entire Forest Dwelling Household System, productive activities within the house garden, cropping and forest extraction, financial and marketing aspects, were analyzed in 60 households (48 in Terra Firme and 12 in Várzea communities). Data concerning demography, socio-cultural aspects, labour force, land tenure were also gathered and analyzed. For this purpose households and key informants were interviewed with the use of a semi-structured questionnaire; participative observation was carried out and market research was executed. The households live basically to sustenance. A purely subsistence oriented family can only be identified as such if its production objectives are merely meant to fulfil subsistence needs. The type of forest dwelling household system existing in the region is strongly marked by small-scale production; the involvement of unpaid family workers in the production process; the combination of the incomes earned from on-, out- and off-farm activities and, to a limited extent, these households live under the threat of poverty. According to the results of the household financial analysis it could be stated that the main financial characteristics of households are the following: a) they are poor and have little ready cash; b) loans to them are usually unavailable; c) they are conscious of an uncertain environment, of cash shortage, and of household responsibilities and therefore are risk-averse; d) they often suffer cyclical labour shortage and under-employment; e) they are economically rational but not necessary profit maximising because they have their own scales of utility. The results of the analysis led to one priority goal, ranked as such by all the households, which was to satisfy the family?s sustenance, namely to supply sufficient food and provide housing for the family at all times. Only when food supply is guaranteed households will think of how to generate cash from their farm, in order to satisfy other needs which are part of an improved standard of living. Commercializing production does not come as a desire to maximize profit, but rather a need to generate cash income for subsistence purposes.

The overall objective of the study was to analyse the Forest Dwelling Systems in the Terra Firme and Várzea communities and to investigate the conditions under which the different activities are allocated across households. In this study, the Farming System Approach facilitates a holistic examination of the Forest Dwelling Household System. This study broadly analyses the importance of natural products and their role as consumption and as goods for cash income for forest dwellers. By focusing on the functions of those products, their role within the Forest Dweller System must be examined. There have been identified differences between the Terra Firme (upland) and Várzea (floodplain) ecosystems management and production systems that are still ignored by decision makers. The study area was identified based on certain criteria: a) accessibility to the area (field support), b) availability of the forest production and, c) ecosystem (Terra Firme and Várzea communities). The survey was conducted in one community at the Terra Firme region (Itacoã) and in three communities at the Várzea region (Monte Tabor, Nova Santa Cruz, Manoel Carneiro). In selecting the households, the dependence on extraction of forest resources as the principal source of income was used as the major criteria, and part-time households were excluded from the studies. In order to obtain data on the structure of the entire Forest Dwelling Household System, productive activities within the house garden, cropping and forest extraction, financial and marketing aspects, were analyzed in 60 households (48 in Terra Firme and 12 in Várzea communities). Data concerning demography, socio-cultural aspects, labour force, land tenure were also gathered and analyzed. For this purpose households and key informants were interviewed with the use of a semi-structured questionnaire; participative observation was carried out and market research was executed. The households live basically to sustenance. A purely subsistence oriented family can only be identified as such if its production objectives are merely meant to fulfil subsistence needs. The type of forest dwelling household system existing in the region is strongly marked by small-scale production; the involvement of unpaid family workers in the production process; the combination of the incomes earned from on-, out- and off-farm activities and, to a limited extent, these households live under the threat of poverty. According to the results of the household financial analysis it could be stated that the main financial characteristics of households are the following: a) they are poor and have little ready cash; b) loans to them are usually unavailable; c) they are conscious of an uncertain environment, of cash shortage, and of household responsibilities and therefore are risk-averse; d) they often suffer cyclical labour shortage and under-employment; e) they are economically rational but not necessary profit maximising because they have their own scales of utility. The results of the analysis led to one priority goal, ranked as such by all the households, which was to satisfy the family?s sustenance, namely to supply sufficient food and provide housing for the family at all times. Only when food supply is guaranteed households will think of how to generate cash from their farm, in order to satisfy other needs which are part of an improved standard of living. Commercializing production does not come as a desire to maximize profit, but rather a need to generate cash income for subsistence purposes.

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This study was to investigate how the introduction of modern physics in high school, mediated by the study of astronomy, may favor the practice of teaching and learning of physics, from the perspective of the Theory of Meaningful Learning (TML), through the use of Sequence Didactic . In order to answer this question, we define the general objective: to analyze how the study of Astronomy, as a mediating element for the introduction of Modern Physics in High School, can favor the teaching and learning of Physics, from the perspective of SAT, in the 3? Series. In order to achieve this purpose, we have drawn up the following specific objectives: to elaborate and evaluate the contribution of a didactic sequence on Electromagnetic Radiation, developed from the perspective of SAT, in the teaching and learning of Physics, in the 3? High School Series; To introduce the study of Modern Physics mediated by Astronomy, with support of didactic sequence on Electromagnetic Radiation, from the perspective of SAT; To evaluate students' performance from the introduction of Modern Physics, mediated by the study of Astronomy, with the support of the Didactic Sequence from the perspective of SAT. From this perspective, it was developed in a senior high school class, in a public school from Santo Antonio de Jesus town, State of Bahia, and entitled "Knowing the Universe Through the Colors". The same had as its central theme Electromagnetic Radiations and constituted both an instrument and product of this research. The activities were designed in a way that would attract students' attention from the curiosity that usually astronomical phenomena cause in those who observe them. At the time they were arranged in ascending order in terms of complexity, and the correlation between them. This research has been prepared under qualitative and quantitative approach, from which have developed a descriptive understanding work of the investigated object. Finally, this study shows a very positive result of the methodology chosen and can say that the Didactic Sequence elaborate contributed to a meaningful learning of concepts covered in Modern Physics, mediated by Astronomy, enabling students to build knowledge that can serve as anchors for future concepts.
Este trabalho consistiu em investigar como a introdu??o da F?sica Moderna no Ensino M?dio, mediado pelo estudo da Astronomia, pode favorecer as pr?ticas de ensino e aprendizagem da F?sica, na perspectiva da Teoria da Aprendizagem Significativa (TAS), a partir do uso de Sequ?ncia Did?tica. Buscando resposta para este questionamento definimos o objetivo geral: analisar como o estudo da Astronomia, enquanto elemento mediador para a introdu??o da F?sica Moderna no Ensino M?dio pode favorecer a pr?tica de ensino e aprendizagem da F?sica, na perspectiva da TAS, na 3? S?rie. Para alcan?ar esse prop?sito tra?amos os seguintes objetivos espec?ficos: elaborar e avaliar a contribui??o de uma sequ?ncia did?tica sobre as Radia??es Eletromagn?ticas, desenvolvida na perspectiva da TAS, no ensino e aprendizado da F?sica, na 3? S?rie do Ensino M?dio; introduzir o estudo da F?sica Moderna mediado pela Astronomia, com suporte de sequ?ncia did?tica sobre Radia??es Eletromagn?ticas, na perspectiva da TAS; avaliar o desempenho dos estudantes a partir da introdu??o da F?sica Moderna, mediado pelo estudo da Astronomia, com o suporte da Sequ?ncia Did?tica na perspectiva da TAS. Nessa perspectiva, foi desenvolvida em uma turma da 3? S?rie do Ensino M?dio, de um Col?gio Estadual do munic?pio de Santo Ant?nio de Jesus, no estado da Bahia, a Sequ?ncia Did?tica intitulada ?Conhecendo o Universo Atrav?s das Cores?, a qual teve como tem?tica central Radia??es Eletromagn?ticas. Esta constituiu-se, simultaneamente, em instrumento e produto da presente pesquisa. As atividades foram pensadas de maneira que atra?ssem aten??o dos alunos, a partir da curiosidade que geralmente os fen?menos astron?micos causam naqueles que os observam. Ao tempo em que foram organizadas de forma ascendente, em termos de complexidade, e primando pela correla??o entre elas. A presente pesquisa foi elaborada sob abordagem quali-quantitativa, a partir da qual desenvolvemos um trabalho descritivo-compreensivo do objeto investigado. As Considera??es Finais evidenciam um resultado muito positivo da metodologia escolhida, podendo dizer que a Sequ?ncia Did?tica elaborada contribuiu para uma aprendizagem significativa dos conceitos abordados da F?sica Moderna, mediados pela Astronomia, possibilitando aos alunos, a constru??o de conhecimentos que poder?o servir de ?ncoras para conceitos futuros.

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Made available in DSpace on 2018-09-12T21:52:11Z (GMT). No. of bitstreams: 1 Vers?o Final_Disserta??o.pdf: 2988104 bytes, checksum: c27862945e0f83da183a6c591a54de39 (MD5) Previous issue date: 2018-06-15
Trading systems based on trend following strategies are applied by many investors when negotiating in the variable income markets, in operations conducted in several asset classes worldwide. These systems play an important role in investor decision-making process, but still require further study. In this dissertation, four trend following trading systems are presented, whose performances have been demonstrated in order to evaluate their effectiveness in the Brazilian variable income market. Two of the four proposed systems were evaluated in the stock market and the other two were considered for the future contract market. For this purpose, a historical series of asset prices available for trade between January 1995 and December 2014 at the S?o Paulo Mercantile and Futures Exchange. Through simulations, the systems showed that if they were traded on the stock market and futures markets in Brazil, they would generate profitability, indicating the existence of several trends in the assets studied, obtaining a performance superior to strategy of buying and hold in the market Ibovespa index. This study contributes to the discussion on the effectiveness of trading systems based on the trend following investment philosophy
Sistemas de negocia??o baseados em estrat?gias fundamentadas no trend following, s?o utilizados por in?meros investidores para negociarem nos mercados de renda vari?vel, em opera??es nas mais variadas classes de ativos no mundo. Esses sistemas desempenham papel importante na tomada de decis?o por parte de um investidor na realiza??o de uma negocia??o, no entanto, ainda precisam de maiores estudos. Nesta disserta??o, apresentamos quatro trading systems seguidores de tend?ncias, os quais tiveram suas performances demonstradas na perspectiva de avaliar a efic?cia desses trading systems no mercado de renda vari?vel brasileiro. Dois dos quatro sistemas propostos, foram avaliados no mercado de a??es e os outros dois foram considerados para opera??es no mercado de contratos futuros. Para tanto, foram consideradas s?ries hist?ricas de pre?os de ativos dispon?veis para negocia??o entre janeiro de 1995 ? dezembro de 2014, na Bolsa de Valores Mercadorias e Futuros de S?o Paulo. Atrav?s de simula??es, os sistemas demonstraram que caso fossem operados no mercado de a??es e/ou de futuros do Brasil, gerariam lucros, indicando-se a exist?ncia de diversas tend?ncias nos ativos estudados, obtendo-se performance superior ? estrat?gia de comprar e manter no ?ndice Ibovespa. O presente trabalho contribui na discuss?o a respeito da efic?cia de sistemas de negocia??o baseados na filosofia de investimento do trend following

In this dissertation, we look for to describe all the trajectory of the application of a didactic sequence, developed in the Padre Pinho school of the municipal network of Maceió, state of Alagoas, with students from two groups of 6th grade. This work is part of Geometry classes, of the normal schedule of class and was developed in the period from August 29, 2016 to January 11, 2017. We work with flat and space geometry using some methodologies, always focusing on plastic art. We started with the use of the textbook and sequenced presenting the works of the plastic artists who work the geometry in their works: Beatriz Milhazes, Geraldo de Barros, Rubens Barsotti, Tarsila do Amaral and Dietmar Voorwold. We wanted to show this intimate relationship between plastic art and mathematics. We also use workshops of origami, scraping technique and construction of geometric solids. A survey test was carried out in which we observed that the classes prepared only with the use of the textbook were not producing the expected learning for that series, even when discussing and performing several exercises and also using geometric elements present in the classroom as the illustration. In this sense, the objective was to develop a didactic sequence that would favor and facilitate the learning of this content, based on the previous information contained in the survey test. For this research, we worked with a group of 60 students, with ages ranging from 10 to 12 years. At all stages, students were invited to reflect and discuss through questions addressed to groups. We sought at all times to discuss and understand the mathematical concepts present. We wanted to show the beauty and the relationship of mathematics to art, as well as to encourage the student to have reflective and questioning behavior. We also aim that this work can also be used by other teachers.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Nesta dissertação, buscamos descrever toda trajetória da aplicação de uma sequência didática, desenvolvida na escola Padre Pinho da rede municipal do município de Maceió, estado de Alagoas, com alunos de duas turmas de 6º ano. Este projeto faz parte das aulas de Geometria, do cronograma normal de aula e foi desenvolvido no período de 29 de agosto de 2016 a 11 de janeiro de 2017. Trabalhamos a geometria plana e espacial mesclando metodologias, tendo sempre como foco principal a arte plástica. Iniciamos com o uso do livro texto e sequenciamos apresentando os trabalhos dos artistas plásticos que trabalham a geometria em suas obras: Beatriz Milhazes, Geraldo de Barros, Rubens Barsotti, Tarsila do Amaral e Dietmar Voorwold. Queríamos com isso, mostrar essa íntima relação da arte plástica com a matemática. Utilizamos também oficinas de origami, técnica de raspagem e construção de sólidos geométricos. Foi realizado um teste de sondagem no qual observamos que as aulas preparadas apenas com a utilização do livro texto não estavam produzindo a aprendizagem esperada para aquela série, mesmo discutindo e realizando vários exercícios e, ainda, utilizando elementos geométricos presentes em sala de aula como a ilustração. Neste sentido, o objetivo foi desenvolver uma sequência didática que viesse a favorecer e facilitar o aprendizado deste conteúdo, baseados nas informações prévias contidas no teste de sondagem. Para esta pesquisa, trabalhamos com um grupo de 60 alunos, com faixa etária entre 10 a 12 anos. Em todas as etapas, os estudantes eram convidados à reflexão e à discussão por meio de perguntas dirigidas aos grupos. Buscávamos em todo momento discutir e entender os conceitos matemáticos ali presentes. Queríamos mostrar a beleza e a relação da matemática com a arte, bem como incentivar o aluno a ter um comportamento reflexivo e questionador. Objetivamos também que este trabalho também possa ser utilizado por outros professores.

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Made available in DSpace on 2018-07-12T22:04:46Z (GMT). No. of bitstreams: 1 CESAR ALVES_Disserta??o_Final revisado vera.pdf: 6440316 bytes, checksum: 9325061c1c7981117303732082343992 (MD5) Previous issue date: 2018-02-01
The main objective of this work was to describe the concepts of Atomic Models, within the scenario of the teaching of chemical reactions, relating them empirically to the processes of chemical luminescence and contextualized to the phenomenon of the planetary Auroras. For this purpose, a proposal was presented to help chemistry teachers to provide students with a better understanding of more meaningful learning. The Teaching of Chemistry in Basic Education presents several challenges regarding the introduction of concepts related to the structure of matter. The approach of this project is centered in the interaction between the Astronomy and the Teaching of Chemistry, in an interdisciplinary perspective with focus in the course of didactic engineering. It is premised that this approach may attract the interest of high school students. The methodology was developed in the classrooms of the Luiz Eduardo Magalh?es College in Feira de Santana-BA. The use of a learning sequence, centered on experimental and observational phenomena where the student's performance is intensified by the possibility of self-regulation and confrontation with the proposed situations, enabled an evolution of strategies, enhancing students' cognition. In an enveloping and structured way in its four phases, the course of didactic engineering contributed to progress in improving teaching and learning, since the agreed proposal was executed and indicates that it is possible to favor the learning of concepts of Teaching Chemistry with emphasis to topics, motivating Students to learn
O principal objetivo deste trabalho foi descrever os conceitos de Modelos At?micos, dentro do cen?rio do ensino de rea??es qu?micas, relacionando-os empiricamente com os processos de luminesc?ncia qu?mica e contextualizados com o fen?meno das Auroras planet?rias. Para o efeito, foi apresentada uma proposta para ajudar os professores de qu?mica a oferecer aos alunos uma melhor compreens?o da aprendizagem mais significativa. O Ensino de Qu?mica na Educa??o B?sica apresenta v?rios desafios em rela??o ? introdu??o de conceitos relacionados ? estrutura da mat?ria. A abordagem deste projeto est? centrada na intera??o entre a Astronomia e o Ensino de Qu?mica, em uma perspectiva interdisciplinar com foco no curso da engenharia did?tica. Pretende-se que esta abordagem possa atrair o interesse dos alunos do ensino m?dio. A metodologia foi desenvolvida nas salas de aula do Col?gio Luiz Eduardo Magalh?es em Feira de Santana-BA. O uso de uma seq??ncia de aprendizagem, centrada em fen?menos experimentais e observacionais, onde o desempenho do aluno ? intensificado pela possibilidade de auto-regula??o e confronto com as situa??es propostas, permitiu uma evolu??o das estrat?gias, aprimorando a cogni??o dos estudantes. De forma envolvente e estruturada em suas quatro fases, o curso de engenharia did?tica contribuiu para o progresso na melhoria do ensino e da aprendizagem, uma vez que a proposta acordada foi executada e indica que ? poss?vel favorecer a aprendizagem de conceitos de Qu?mica de Ensino com ?nfase em t?picos, motivando esudantes para aprender

碩士
國立中興大學
環境工程學系
89
This research follows the vertical-diffusion model of the aerial pollutants , which was developed by our laboratory in year 2000. On the basis of the theory of the advection-diffusion equation , the reference frame is changed from rectangular coordinate system (x，y，z) into terrain following coordinate system (x，y，z''). In that case, we can derive a partial differential equation of the first and the twelfth layers above the ground and use the equation to simulate the primary and second aerosol pollutants.Utilizes finite-difference approximations to the derivatives in the equation to change the differential equation to difference equation, the governing equation can be performed as tridiagonal matrix. Then I introduce in L U decomposition method to the repeat repetitious calculation with C++ programming language on the Linux work station. Advection term,vertical and horizontal diffusion term,pollutants emitted from stacks of each layer,dry deposition,scavenging,chemical reaction,instantaneous meteorological condition,mixing height,etc. are all taken into consideration in this model. The model is proved empirically by comparing calculated values with the observed values experimented from October 30 to September 6 in year 1999. In those simulation cases, I select two days─Oct.30 and Sep.5, the day is the PM10 episode─of back of high pressure system to make a comparison and discussion. The comparison of the two graphs, the GrADS graph of the streak lines and the contour graph of pollutants, is introduced into model to apparently show the influence hit by the fetal pollutive sources of central Taiwan.

This thesis makes a number of new contributions to control and sensing for unmanned vehicles. I begin by developing a non-linear simulation of a small unmanned helicopter and then proceed to develop new algorithms for control and sensing using the simulation. The work is field-tested in successful flight trials of biologically inspired vision and neural network control for an unstable rotorcraft. The techniques are more robust and more easily implemented on a small flying vehicle than previously attempted methods. ¶ ...