La prédation exercée par le Chat domestique (Felis silvestris catus) joue un rôle majeur dans la conservation de certaines espèces proies et la prévention de zoonoses. L'objectif de cette étude était d'identifier les facteurs de variation de cette prédation en milieu rural. L'étude a été conduite dans les Ardennes. La population étudiée comptait 143 individus, dont 44 % de chats de propriétaire (nourris ad libitum, 80 % stérilisés) et 56 % de chats de ferme (peu nourris, non stérilisés). Le DNA metabarcoding et le génotypage ont permis de détecter la fréquence d'apparition des aliments dans des fèces collectées sur le terrain et d'attribuer ces fèces à l'une ou l'autre des catégories de chats. Des individus ont été équipés de colliers GPS et d'accéléromètres tridimensionnels. L'éthogramme accélérométrique d'une séquence de chasse a été construit afin de pouvoir, à terme, relever les événements de prédation et de consommation des proies des individus équipés. Enfin, des variables associées à la prédation ont été mise en relation avec leur sociabilité envers les humains. Les chats ont essentiellement consommé des rongeurs et des aliments d'origine anthropique. En été, les chats de propriétaire chassaient aussi fréquemment que les chats de ferme, tandis qu'en hiver ils chassaient beaucoup moins souvent que ces derniers. Les chats de propriétaire ont de plus petits domaines vitaux que les chats de ferme. Les deux catégories de chats ont un rayon d'action restreint lorsque la pluviométrie est élevée et ont pour proies principales Microtus arvalis et Arvicola terrestris. Le degré de sociabilité des chats vis-à-vis des humains semble affecter leur succès de capture diurne de proies. / The predation exerted by the Domestic cat (Felis silvestris catus) is of special concerns for conservation and prevention of zoonosis issues. This study aims to identify the factors of variation of the predation exerted by cats in a rural landscape. It has been conducted in the Ardennes region. The population studied was composed of 143 individuals, including 44% of house cats (fed ad libitum, 80% sterilized) and 56% of farm cats (poorly fed, not sterilized). DNA metabarcoding and genotyping technics allowed to detect occurrences of food items in field-collected feces and to attribute those feces to one or the other cat categories. Some individuals were equipped with a collar composed by a GPS unit and a tri-axial accelerometer device. The ethogram of a hunting sequence based on accelerometry was constructed to gather information concerning the occurrences of predation and the consumption of the preys by the equipped individuals. Finally, some variables associated to the predation were put in relation with the sociability of cats towards humans. The cats essentially consumed rodents and anthropogenic food. During the summer, the house cats were hunting as frequently as the farm cats, whereas during the winter they were hunting a lot less comparing to the farm cats. Both cat categories have smaller daily movement range during high rainfall periods and their main preys are Microtus arvalis and Arvicola terrestris. The sociability degree of the cats towards humans seems to affect their diurnal stalk success.

Este trabalho descreve um ataque que detecta as teclas pressionadas em teclados mecânicos pela análise das vibrações geradas quando as mesmas são pressionadas. Dois equipamentos foram experimentados no ataque: um teclado genérico de automação comercial e um terminal de ponto de venda (POS / PIN-pad). Acelerômetros são utilizados como sensores de vibração. Propositalmente, o equipamento necessário para a execução do ataque é de baixíssimo custo, de modo a ressaltar o risco das vulnerabilidades encontradas. Obtivemos taxas de sucesso médio de 69% no reconhecimento das teclas pressionadas para o terminal PIN-pad em repouso e 75% para o mesmo sendo segurado na mão. No caso de teclado de automação comercial, as taxas médias de acerto ficaram em torno de 99%. / This work describes an attack that identifies the sequence of keystrokes analyzing mechanical vibrations generated by the act of pressing keys. We use accelerometers as vibration sensors. The apparatus necessary for this attack is inexpensive and can be unobtrusively embedded within the target equipment. We tested the proposed attack on an ATM keypad and a PIN-pad. We achieved the key recognition rates of 99% in ATM keypad, 69% in PIN-pad resting on a hard surface and 75% in PIN-pad hold in hand.

Made available in DSpace on 2016-12-23T14:07:26Z (GMT). No. of bitstreams: 1 Alexandre Secchin de Melo - parte 1.pdf: 1376671 bytes, checksum: 7504ac977143d6adfd9ac0c7c2bc0d2f (MD5) Previous issue date: 2010-06-30 / Este trabalho visa a implementação de um objeto voador não-tripulado, em formato miniatura, com quatro rotores como plataforma de desenvolvimento, como parte de uma pesquisa mais abrangente. O objetivo final, ainda por ser alcançado, é chegar a um veículo voador miniatura com o máximo grau de autonomia de decisões baseadas no sensoreamento a bordo e poder computacional embarcados, estratégia do controle inteligente, e tarefa a cumprir. Tal implemetação, até o momento, consiste em uma máquina eletro-mecânica de baixo custo, cuja parte eletrônica a bordo, um microcontrolador de 8 bits, acelerômetros e giroscópios do tipo MEMS, permite a implementação de um controlador de voo genérico para automatizar a sua estabilização em torno dos eixos X, Y e Z. Tem vasta gama de aplicações como: inspeções aéreas em diversos ambientes, como linhas de transmissão elétrica, detecção de foragidos da polícia, monitoramento de plantações e rebanhos, bem como tomadas de filmagens para as indústrias cinematográfica e imobiliária. Testes realizados com o protótipo até agora sugerem a implementação bem sucedida de um controlador de estabilização de voo / This work aims the implementation of a unmanned, four-rotor miniature flying machine as a development platform, part of a long term research. The final goal, yet to be achieved, is the realization of a flying object with maximum practicable degree of autonomous decisions based on the on-board sensory and computational power, control strategy and assigned task. Up to this work, it consists of a low cost electro-mechanical hardware, whose electronic part allows the implementation of an 8-bit microcontroller-based, MEMS accelerometer and gyroscopes, allows the implementation of a generic fly control for attitude stabilization. The broad spectrum of applications includes: the inspection of various kinds of environments such as electric power transmission lines, police surveillance of woods and hard-to-reach places with sky sight for fugitive detection, crops and herd monitoring, as well as film takings for the cinematographic and real estate industries. Tests undertaking so far with the prototype suggest the successful implementation of a fly attitude controller

Este trabalho descreve um ataque que detecta as teclas pressionadas em teclados mecânicos pela análise das vibrações geradas quando as mesmas são pressionadas. Dois equipamentos foram experimentados no ataque: um teclado genérico de automação comercial e um terminal de ponto de venda (POS / PIN-pad). Acelerômetros são utilizados como sensores de vibração. Propositalmente, o equipamento necessário para a execução do ataque é de baixíssimo custo, de modo a ressaltar o risco das vulnerabilidades encontradas. Obtivemos taxas de sucesso médio de 69% no reconhecimento das teclas pressionadas para o terminal PIN-pad em repouso e 75% para o mesmo sendo segurado na mão. No caso de teclado de automação comercial, as taxas médias de acerto ficaram em torno de 99%. / This work describes an attack that identifies the sequence of keystrokes analyzing mechanical vibrations generated by the act of pressing keys. We use accelerometers as vibration sensors. The apparatus necessary for this attack is inexpensive and can be unobtrusively embedded within the target equipment. We tested the proposed attack on an ATM keypad and a PIN-pad. We achieved the key recognition rates of 99% in ATM keypad, 69% in PIN-pad resting on a hard surface and 75% in PIN-pad hold in hand.

Activity recognition research in computer vision and pervasive computing has made a remarkable trajectory from distinguishing full-body motion patterns to recognizing complex activities. Manipulation activities as occurring in food preparation are particularly challenging to recognize, as they involve many different objects, non-unique task orders and are subject to personal idiosyncrasies. Video data and data from embedded accelerometers provide complementary information, which motivates an investigation of effective methods for fusing these sensor modalities. This thesis proposes a method for multi-modal recognition of manipulation activities that combines accelerometer data and video at multiple stages of the recognition pipeline. A method for accelerometer tracking is introduced that provides for each accelerometer-equipped object a location estimate in the camera view by identifying a point trajectory that matches well the accelerometer data. It is argued that associating accelerometer data with locations in the video provides a key link for modelling interactions between accelerometer-equipped objects and other visual entities in the scene. Estimates of accelerometer locations and their visual displacements are used to extract two new types of features: (i) Reference Tracklet Statistics characterizes statistical properties of an accelerometer's visual trajectory, and (ii) RETLETS, a feature representation that encodes relative motion, uses an accelerometer's visual trajectory as a reference frame for dense tracklets. In comparison to a traditional sensor fusion approach where features are extracted from each sensor-type independently and concatenated for classification, it is shown that combining RETLETS and Reference Tracklet Statistics with those sensor-specific features performs considerably better. Specifically addressing scenarios in which a recognition system would be primarily used by a single person (e.g., cognitive situational support), this thesis investigates three methods for adapting activity models to a target user based on user-specific training data. Via randomized control trials it is shown that these methods indeed learn user idiosyncrasies. All proposed methods are evaluated on two new challenging datasets of food preparation activities that have been made publicly available. Both datasets feature a novel combination of video and accelerometers attached to objects. The Accelerometer Localization dataset is the first publicly available dataset that enables quantitative evaluation of accelerometer tracking algorithms. The 50 Salads dataset contains 50 sequences of people preparing mixed salads with detailed activity annotations.

Family Child Care Homes (FCCHs) are the second largest provider of non-relative care in the U.S. However, despite providing care for nearly 1.9 million children under the age of 5, little is known about the physical activity levels of children attending FCCHs. This dissertation sought to provide new information with regards to physical activity in children attending FCCHs. The purpose of the first study was to objectively measure physical activity in children attending FCCHs. 114 children (60 boys and 54 girls) 3.7 �� 1.1 years of age from 47 FCCHs wore an ActiGraph GT1M accelerometer for the duration of child care attendance during a randomly selected week. Counts were classified as sedentary (SED), light (LPA), or moderate-to-vigorous (MVPA) using the cut-points developed by Pate et al. (2006). Total physical activity was calculated by summing time spent in LPA and MVPA. Non-wear time was estimated by summing the number of consecutive zero counts accumulated in strings of 10 minutes or longer. Children were included in the analyses if they had 2 or more monitoring days in which wear time was ���75% of the attendance time. On average, children accumulated 25.9 �� 5.7 min of SED, 10.1 �� 4.2 min of MVPA, and 34.1 �� 5.7 min of total physical activity per hour of attendance. Further analysis revealed that among healthy weight children, 4 year-olds exhibited significantly lower levels of SED and significantly higher levels of MVPA and total physical activity than 2- and 3- year-olds. Among 4-year-olds, overweight and obese children exhibited significantly higher levels of SED and significantly lower levels of MVPA and total PHYSICAL ACTIVITY than healthy weight counterparts. The results from this study indicated that preschool-aged children attending FCCHs are mostly sedentary and accumulate low levels of MVPA during the child care day. The purpose of the second study was to assess the validity of two proxy report instruments designed to measure physical activity in children attending FCCHs. Valid self-report measures are needed for large scale intervention studies and/or population-based surveillance studies in which more burdensome objective measures are not feasible. In Year 1 of the study, FCCH Providers (N=37) completed the Burdette parent proxy report, modified for the family child care setting, for 107 children aged 3.4 �� 1.2 years. In Year 2, 42 Providers completed the Harro parent and teacher proxy report, modified for the family child care setting, for 131 children aged 3.8 �� 1.3 years. Both proxy-reports were assessed for validity using objectively measured physical activity as a criterion measure (accelerometry). Significant positive correlations were observed between scores from the modified Burdette proxy report and objectively measured total physical activity (r = 0.31, p < 0.01) and MVPA (r = 0.33, p < 0.01). Across levels of Provider-reported activity, both total physical activity and MVPA increased significantly in a linear dose-response fashion. Provider-reported MVPA scores from modified Harro proxy report were not associated with objectively measured physical activity. These findings suggested that the modified Burdette proxy report may be a useful measurement tool in larger-scale physical activity studies involving FCCHs in which objective measures, such as direct observation or accelerometry, are not practical. The purpose of the third study was to evaluate the effects of two strategies to increase the use of portable play equipment in FCCHs ��� a community-based train-the-trainer physical activity intervention (INT), and the same trainer-the-trainer intervention supplemented with monthly emails promoting the use of portable play equipment (INT+). We hypothesized that Providers completing the standard train-the-trainer intervention would report significantly greater portable play equipment use than Providers completing the food allergy control training (CON). We further hypothesized that Providers completing the supplementary email intervention would report significantly greater portable play equipment use than Providers completing standard train-the-trainer intervention or the food allergy control training. A total of 50 FCCH Providers from Marion, Linn, Benton, Washington, and Lane County, Oregon were randomized to the INT or CON conditions. Twelve Providers from Lincoln County were assigned to the (INT+). The type, variety, and frequency of portable play equipment use was measured by means of self-report via a checklist and two items from the previously validated NAP-SACC Self-Assessment instrument. FCCH Providers who completed the INT reported significantly greater use of portable play equipment than Providers completing the CON training. However, portable play equipment use among Providers completing the INT+ was not significantly different from that reported by Providers in the INT or CON. Notably, neither intervention had a significant impact on the amount or variety of portable play equipment. The results showed that a comprehensive trainer-the-trainer intervention to increase physical activity in FCCHs could successfully increase the use of portable play equipment in the home. However, supplementing the intervention with monthly emails encouraging the use of PPE was not effective. / Graduation date: 2013

On March 13th, 2006, the Division of Electricity at Uppsala University deployed its first wave energy converter, L1, in the ocean southwest of Lysekil. L1 consisted of a buoy at the surface, connected through a line to a linear generator on the seabed. Since the deployment, continuous investigations of how L1 works in the waves have been conducted, and several additional wave energy converters have been deployed. This thesis is based on ten publications, which focus on different aspects of the interaction between wave, buoy, and generator. In order to evaluate different measurement systems, the motion of the buoy was measured optically and using accelerometers, and compared to measurements of the motion of the movable part of the generator - the translator. These measurements were found to correlate well. Simulations of buoy and translator motion were found to match the measured values. The variation of performance of L1 with changing water levels, wave heights, and spectral shapes was also investigated. Performance is here defined as the ratio of absorbed power to incoming power. It was found that the performance decreases for large wave heights. This is in accordance with the theoretical predictions, since the area for which the stator and the translator overlap decreases for large translator motions. Shifting water levels were predicted to have the same effect, but this could not be seen as clearly. The width of the wave energy spectrum has been proposed by some as a factor that also affects the performance of a wave energy converter, for a set wave height and period. Therefore the relation between performance and several different parameters for spectral width was investigated. It was found that some of the parameters were in fact correlated to performance, but that the correlation was not very strong. As a background on ocean measurements in wave energy, a thorough literature review was conducted. It turns out that the Lysekil project is one of quite few projects that have published descriptions of on-site wave energy measurements.

Significant advances in wind turbine technology have increased the need for maintenance through condition monitoring. Indeed condition monitoring techniques exist and are deployed on wind turbines across Europe and America but are limited in scope. The sensors and monitoring devices used can be very expensive to deploy, further increasing costs within the wind industry. The work outlined in this thesis primarily investigates potential low-cost alternatives in the laboratory environment using vibration-based and modal testing techniques that could be used to monitor the condition of wind turbine blades. The main contributions of this thesis are: (1) the review of vibration-based condition monitoring for changing natural frequency identification; (2) the application of low-cost piezoelectric sounders with proof mass for sensing and measuring vibrations which provide information on structural health; (3) the application of low-cost miniature Micro-Electro-Mechanical Systems (MEMS) accelerometers for detecting and measuring defects in micro wind turbine blades in laboratory experiments; (4) development of an in-service calibration technique for arbitrarily positioned MEMS accelerometers on a medium-sized wind turbine blade. This allowed for easier aligning of coordinate systems and setting the accelerometer calibration values using samples taken over a period of time; (5) laboratory validation of low-cost modal analysis techniques on a medium-sized wind turbine blade; (6) mimicked ice-loading and laboratory measurement of vibration characteristics using MEMS accelerometers on a real wind turbine blade and (7) conceptualisation and systems design of a novel embedded monitoring system that can be installed at manufacture, is self-powered, has signal processing capability and can operate remotely. By applying the conclusions of this work, which demonstrates that low-cost consumer electronics specifically MEMS accelerometers can measure the vibration characteristics of wind turbine blades, the implementation and deployment of these devices can contribute towards reducing the rising costs of condition monitoring within the wind industry.

This thesis work provides an insight into the design of Force-amplifying Compliant Mechanisms (FaCMs) that are integrated with micromachined resonant accelerometers to increase their sensitivity. An FaCM, by mechanically amplifying the inertial force, enhances the shift in the resonance frequency of the beams used for sensing the acceleration whose effect causes an axial force on the beams. An extensive study on different configurations of resonators namely, single beam resonator, single-ended tuning fork (SETF), and double-ended tuning fork (DETF), is carried out to gain insights about their resonant behavior. The influence of the boundary conditions on the sensor’s sensitivity emerged from the study. We found that not only the force-amplification factor but also the multi-axial stiffness of the FaCM and proof-mass influence the resonance frequency of the resonator as well as the bandwidth of the modified sensor for certain configurations but not all. Thus, four lumped parameters were identified to quantify the effectiveness of an FaCM. These parameters determine the boundary condition of the sensing beams and also the forces and the moment transmitted to them. Also presented in this work is a computationally efficient model, called the Lumped Parameter Model (LPM) for evaluation of the sensitivity. An analytical expression for the frequency-shift of the sensing resonator beams is obtained by considering the FaCM stiffness parameters as well as the lumped stiffness of the suspension of the inertial mass. Various FaCMs are evaluated and compared to understand how the four lumped parameters influence the sensor’s sensitivity. The FaCMs are synthesized using topology optimization to maximize the net amplification factor with the volume constraint. One of the FaCMs outperforms the lever by a factor of six. Microfabrication of resonant accelerometer coupled with FaCM and comb-drive actuator is carried out using a silicon-on-insulator process. Finally, the selection map technique, a compliant mechanism redesign methodology is used for enhancing the amplification of FaCMs. This technique provides scope for further design improvement in FaCMs for given sensor specifications.

This thesis deals with inertial navigation systems issues. It describes basics of reference frames, coordinate systems and matrix calculations for AHRS. There are also basic information about inertial sensors, inertial measurements units and its mistakes. One of the purposes of this paper could be explanation of inertial navigation systems terms. The main object of this thesis is to explore the influence of using multiple sensors of same type to enhance measurements of AHRS systems.