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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
241

Development of a Multi Sensor Android Application

Maddala, Sasanka, Velugubantla, Veerababu January 2020 (has links)
There has been an enormous growth in the usage of smartphones in recent times. Smartphones are not limited to communication purposes. It has various applications designed as per the daily requirements of humans such as web-searching, online shopping, bank transactions, games, etc. With the increase in the usage of the smartphone, the more useful information is captured and stored by it, which raises the question of security. The goal of this research is to develop two android applications. One is a sensor detector application and the second is a screen lock application. The first application will help the user to identify all the hidden sensors and working sensors on the mobile phone. This application even describes the features and usage of every sensor in detail. Using a graphical description of each sensor which depicts the behaviour of each sensor as per environment/movement. The second application is designed using a combination of two sensors. Screen lock applications contain two main factors. One is to work properly in all cases and efficiently do the functions that are required to do. The second is to maintain a smooth inner system interaction because in addition to locking the screen this application should make sure to hide the display of all the other applications without closing the process of these applications. With the increase in the usage of the smartphone, it becomes difficult for older generations to memorize the security pattern techniques and use them. This thesis develops a simple technique in the mobile authentication android application. The thesis is developed on the Android studio platform. The background functionality of the app is coded in java using android SDK tool and frontend of the application is designed using XML files. The GENYMOTION emulator and a mobile phone are used to test the output.
242

Concurrent validity of an inertial sensor for measuring muscle mechanical properties

Olovsson Ståhl, Elias, Öhrner, Pontus January 2020 (has links)
Background: The usage of the Force-Velocity relationship for individualizing training regimes for athletes has increased in popularity. This can be done through measurements of muscle mechanical properties and creating individual force-velocity profiles. To do this, one must use valid and reliable test equipment. These types of equipment are often expensive and impractical, which limits the usage to a small population with the right financial means. Therefore, the purpose of this study was to examine the concurrent validity of the inertial sensor Vmaxpro for measuring muscle mechanical properties. Method: 52 male ice-hockey players (age:17.9 ± 2.2 years, body weight: 77.7 ± 10.6 kg, height: 180.3 ± 6.2 cm) participated in this study and performed two jumps each on four different loading conditions (unloaded, 25, 50 and 75% of BW). The jumps were recorded simultaneously with an inertial sensor and a linear transducer. Three different variables were analyzed: peak velocity (pV), average velocity (avgV) and average power (avgP). Pearson’s correlation coefficient (r), linear regression analysis, Bland-Altman analysis, and standard error of estimate (SEE) was used to examine the concurrent validity. Results: The results showed a strong correlation, agreement and small SEE for pV: r=0.98, bias = -0.12, SEE = 0.08, for avgV: r=0.98 bias = 0.01, SEE = 0.04 and for avgP: r = 0.97, bias = 30.94, SEE = 73.47. Practical application: The results from the present study indicate that the Vmaxpro can be used for assessing muscle mechanical properties. Furthermore, since the Vmaxpro is both cheap and portable, it can potentially expand the usage of test equipment to clubs and associations with limited budgets.
243

Adaptations respiratoires et locomotrices des sujets obèses lors du test de marche de six minutes / Respiratory and locomotor adaptations of obese subjects during 6 minute walk test

Retory, Yann 25 January 2017 (has links)
La méthode de référence pour l’évaluation de la capacité d’exercice est l’Exploration Fonctionnelle d’eXercice (EFX). En pratique, pour des problèmes de coût, de matériel et d’expertise médicale, l’EFX n’est pas réalisée chez tous les sujets dont la capacité d’exercice mérite d’être explorée. Le test de marche de 6 minutes (6MWT) ne présente pas ces inconvénients mais ne donne pas d’informations sur les adaptations physiologiques au cours de cet exercice. L’objectif de ce travail de thèse était de concevoir une méthode non invasive de monitorage des adaptations ventilatoires et locomotrices. L’accent a été porté sur le respect du caractère spontané de ces adaptations. La pléthysmographie respiratoire d’inductance (RIP) et l’accélérométrie ont été choisies pour l’évaluation de ces adaptations. Les performances de ces nouvelles méthodes de monitorage sont acceptables pour ces deux dimensions. La confrontation de notre méthode RIP au pneumotachographe, outil de référence, objective des coefficients de corrélations compris entre 0,81 et 0,96 pour le volume courant(Vt), les temps inspiratoires (Ti) et expiratoires (Te). De même, la confrontation de notre méthode accélérométrique avec le contrôle vidéographique montre des coefficients de corrélations de 0,99 pour les paramètres locomoteurs : cadence, longueur moyenne du pas et détermination automatique des distances parcourues (6MWD). La comparaison des profils ventilatoires et locomoteurs entre contrôles et sujets obèses révèle qu’une discrimination est possible (p<0,01 pour Vt, Ti, Te et p<0 ,001 pour cadence, longueur moyenne de pas et 6MWD). Ainsi, même une population sans pathologie respiratoire comme la population obèse sans comorbidités, choisie comme modèle d’étude dans ce travail, peut être discriminée par notre méthode de monitorage. Ces résultats sont encourageants au regard de l’amélioration de la prise en charge des sujets obèses et laissent entrevoir des perspectives tant au niveau technologique qu’à un niveau clinique plus large pour, par exemple, les sujets atteints de pathologies respiratoires susceptibles de limiter leur capacité d’effort. / The reference method for assessment of exercise capacity is the cardio-pulmonary exercise testing (CPET). Nevertheless, CPET is expensive, time consuming, requires specifics skills and is not used for all subjects needing exercise capacity assessment. The 6 minute walk test (6MWT) is free of these disadvantages but does not give basic information about physiological adaptation induced by walking. The aim of this study was to design a non-invasive method for ventilatory and locomotor monitoring. Respect of the spontaneous aspects of these adaptations was considered. Respiratory inductive plethysmography (RIP) was considered for ventilatory evaluation whereas locomotor adaptation was assessed with a tri-axial accelerometer. These new methods provided acceptable results for ventilatory and locomotor dimensions. Confronting our new RIP method with a pneumotachograph as a reference device, we found correlation coefficients from. 0.81 to 0.96 for determination of tidal volume (Vt), inspiratory (Ti) and expiratory time (Te). Confronting our accelerometric method with video recordings as control, we found significant correlation coefficients (r=0.99 and p< 0.001) for determination of cadence, mean step length and automatic distance covered (6MWD) during the 6MWT. Comparisons of ventilatory and locomotor pattern of control and obese without comorbidities showed that discriminating their pattern was possible (p<0.01 for Vt, Ti, Te and p<0.001 for cadence, mean step length and 6MWD). These results imply that even a population without respiratory disorders as the obese population considered in this study, can be discriminated with our monitoring method. It can be concluded that this method is promising for improvement of care to obese subjects and raises technological and clinical perspectives for subjects with respiratory disorders
244

Effect of an Aerobic Exercise Program on Daily Energy Expenditure and Intake in Adolescents.

Biagé, Alyssa January 2016 (has links)
Objectives: The purpose of this study was to investigate the effect of an 8-week aerobic exercise program on daily energy expenditure and intake in adolescents with normal-weight and with overweight or obesity. Methods: Prospective intervention study. The study included twenty-six adolescents aged between 14-18 years: 17 adolescents (8 girls and 9 boys) with normal-weight (BMI <85th percentiles for age and sex), and 9 adolescents (5 girls and 4 boys) with overweight or obesity (BMI 85th percentile for age and sex). The aerobic exercise program included 30 minutes of cycling performed on a Monark cycle ergometer 3 times a week for 8 weeks at an exercise target heart rate at 75% of participants’ heart rate reserve using the Karvonen formula. Total daily energy expenditure was measured with an indirect calorimeter wear for resting metabolic rate and a 7-day accelerometer for energy expenditure from physical activity. Energy intake was estimated with 24-hour recalls. Results: The aerobic exercise program did not have any significant effect on body weight. Significant effects of aerobic exercise on total daily energy expenditure (p=.051), energy expenditure from physical activity (p=.031) and total daily energy intake (p=.008) were observed, which mainly revealed a reduction in daily physical activity and energy intake following the exercise program. However, there was no significant effect of weight status and no interaction effect between of aerobic exercise and weight status for those three variables. Conclusions: Adolescents with normal weight, overweight or obesity not only reduced their daily total energy expenditure by reducing physical activity, but simultaneously decreased their total daily energy intake after an aerobic exercise program.
245

Tilt sensing with low-cost inertial measurement units (IMUs) : Sensor calibration, accuracy specifications and application range

Riedesel, Philipp January 2016 (has links)
Many surveying engineering applications require the knowledge of the orientation parameters of instruments. One can use inertial measurement units (IMUs) to determine that. IMUs are combinations of several inertial sensors and comprise at least an accelerometer and a gyroscope. Therefore, they can detect accelerations and angular rates in a three-dimensional space. As micro-electro-mechanical systems, the sensors are increasingly getting smaller and lighter, but without being reduced in their accuracy. The smaller size facilitates diverse placing of the sensors, which allows a variety of uses. Moreover, several low-cost IMUs have been devised since the development of single-board computers. The main objectives of this work are to determine tilts using a low-cost IMU, and the accuracy of the sensor. Furthermore, it studies general IMU applications in surveying engineering, and examines whether low-cost versions are applicable. To fulfil the objectives, the study was based on a selected low-cost IMU. Two programs were developed as part of this work. One was to control the sensor and the other, to calculate the tilts and analyse the data. The IMU was mounted in front of the objective of the total station and aligned in different reference orientations. All measurements were performed under controlled thermal conditions. Thereby, it was ensured that no falsifications could appear due to ambient temperature influences. As a first step, the sensor calibration process was completed. It helped determine the signal offset parameter and their time-dependent change. The calibration was done using two present methods, the six-position and the multi-position methods. The calibrated IMU helped determine the tilts. This was done in the case of the accelerometer via trigonometric functions, which allowed an absolute orientation statement. In contrast, the gyroscope provided relative orientation with the multiplication of the detected angular variance and the time that passed. After that, a target-actual comparison with the reference information of the total station helped determine the external accuracy of the tilt from the IMU. Moreover, multiple measurements could give a statement of the internal accuracy. Finally, the Kalman Filter was added to smooth out the sensor data and combine it in real-time. The calibration methods showed similar results, and it was striking that the sensors did not show the expected drifts. The reason could be related to a pre-calibration by the manufacturer. On the one hand, the used IMU showed differences in the total station alignments in the order of 0.798° for the accelerometer and up to 4.3° for the gyroscope with the calibrated data. On the other, the differences in repeated measurements were at 0.024° for the accelerometer and 0.5° for the gyroscope. It was figured out different possible applications of IMUs in surveying engineering. Among other things, these included orientation monitoring of sensor platforms or the determination of the external orientation of unmanned aerial systems. For these applications, the usability depends on the achievable accuracy. In the case of the IMU chosen in this study, the proven accuracy is too inaccurate for these applications. There is a need for further investigation because the use of another sensor type may rectify the insufficient accuracy problem. Moreover, to achieve better accuracies and to make it possible to use the IMU in different ambient temperatures, the temperature influence must be determined.
246

Analysis of comparative filter algorithm effect on an IMU

Åkerblom Svensson, Johan, Gullberg Carlsson, Joakim January 2021 (has links)
An IMU is a sensor with many differing use cases, it makes use of an accelerometer, gyroscope and sometimes a magnetometer. One of the biggest problems with IMU sensors is the effect vibrations can have on their data. The reason for this study is to find a solution to this problem by filtering the data. The tests for this study were conducted in cooperation with Husqvarna using two of their automowers. The tests were made by running the automowers across different surfaces and recording the IMU data. To find filters for the IMU data a comprehensive literature survey was conducted to find suitable methods to filter out vibrations. The two filters selected for further testing were the complementary filter and the LMS filter. When the tests had been run all the data was added to data sheets where it could be analyzed and have the filters added to the data. From the gathered data the data spikes were clearly visible and were more than enough to trigger the mower's emergency stop and need to be manually reset. The vibrations were too irregular to filter using the LMS filter since it requires a known signal to filter against. Hence only the complementary filter was implemented fully. With the complementary filter these vibrations can be minimized and brought well below the level required to trigger an emergency stop. With a high filter weight constant such as 0.98, the margin of error from vibrations can be brought down to +- 1 degrees as the lowest and +- 4,6 degrees as highest depending on the surface and automower under testing. The main advantage with using the complementary filter is that it only requires one weight constant to adjust the filter intensity making it easy to use. The one disadvantage is that the higher the weight constant is the more delay there is on the data.
247

Aplikace počítače v ultralehkém letounu / Applications of Computers in Ultramicro Aircraft

Žůrek, Daniel January 2017 (has links)
The master thesis deals with the possibilities for monitoring the operation of ultralight aircraft or helicopters . The aim is to create a system for the determination of aircraft operating parameters with a main focus on motion detection and evaluation . The thesis describes speed sensing methods , acceleration measurement , frequency measurement methods , wireless communication , serial line communication , hardware and software implementation of the embedded system, and finally description of the implementation of the mobile application .
248

MEMS inerciální snímače / MEMS Inertial Sensor

Mihaľko, Juraj January 2012 (has links)
The aim of this master’s thesis was to describe the basic measurement methods for measurement of inertial sensor, their physical principles and errors. The next step was to select a specific parameter, then test it on a number of sensors and evaluate the results. Measurement of inertial sensors is very important for the parametrization of their errors and their subsequent mathematical model by which it is possible to minimize their impact on inertial navigation. The practical part is dedicated to the measurement of stability of the offset. Data acquisition card NI-USB 6215, which can supply two accelerometers at the same time using analog outputs, was used for data acquisition and power supply. It was tested on seven inertial sensor from four manufacturers. Two connection methods with NI-USB 6215, by whose it was determined which one is better to suppress the crosstalk between channels, were used for measurement. The NI PXI 4462 was used to verify that the NI-USB 6215 card is sufficient. The parameters for description of the changes in inertial sensors were established, transition between the initial and final value of the output measurement, variance of the values on which the sensor fixates after 72 iterations, and the fixation time of the sensor.
249

Sledování pohybu materiálu v průběhu výroby / Material position tracking in production hall

Sládeček, Michal January 2018 (has links)
This diploma thesis describes implementation of an indoor positioning system for tracking the location and movement of material and products through the manufacturing plant. The system is designed with regards to simple installation and low overall implementation costs. It utilizes method of Wi-Fi and magnetic field fingerprinting. The system employs a client hardware (active tag with Wi-Fi module and sensors designed for this project) communicating with a server software which does the mapping and fingerprinting processing. Finall positioning system is prepared to collect locations data for further analysis aiming to improve efficiency of manufacturing processes.
250

Analýza využití SMART materiálů jako aktivních prvků pro snímáni vibrací / Analysis of SMART Material Usage in case of Active Vibration Sensing

Rabčan, Jakub January 2019 (has links)
This diploma thesis deals with the possibility of vibration sensing and vibrodiagnostics based on the use of so-called "SMART" materials such as piezoelectric layers or structures. Research studies have examined the general overview of vibrodiagnostic methods and their analysis of the possibility of sensing vibration by piezoelectric structures. This was followed by measuring and evaluating the results using various vibro-diagnostic methods. The results were compared with those obtained by sensing vibration using an accelerometer. We also dealt with the problem of detecting the deformation of the device by sensing vibration with piezoelectric structures. The last part was programming the "Myrio" to capture and evaluate the vibration using Labview.

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