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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.
1

Quasi-Optical Spherical Balloon Telescopes

O'Dougherty, Stefan, O'Dougherty, Stefan January 2018 (has links)
Astronomy constantly pushes the limits of technology in order to decipher the workings of the Universe. There is a constant need for higher resolution observations across a wide range of wavelengths, at preferably a minimal cost. The terahertz regime (lambda=100 um to lambda=1000 um) covers a region of the electromagnetic spectrum that is blocked by Earth's atmosphere, which limits observations to high altitude plane and balloon telescopes and space telescopes. These current options limit the resolution achievable due to the size of telescopes that can be launched. This dissertation investigates a new approach, the Large Balloon Reflector (LBR), where a 20 meter diameter spherical balloon can be inflated and used as a 10 meter telescope inside a larger carrier balloon. Detailed in this dissertation are design considerations for the terahertz regime and a series of scaled versions of this balloon concept where I work to develop on-axis spherical corrector designs. Chapters 1 through 6 focus on the LBR designs and their variants, including investigations for a 3 meter rooftop proof of concept model, a 5 meter test flight model, and the final 20 meter LBR. The successful modeling and proof of concepts from the LBR studies then prompted an investigation into a Terahertz Space Telescope (TST), a proposed 20 meter inflatable telescope adapted from the LBR technology. Starting with Chapter7, this dissertation explores the application of using 1 meter diameter inflatable balloons as rapidly deployable communications satellites from standard CubeSats. The concept, design and test results of an electronically steerable line feed antenna array are presented which allows for instantaneous, non mechanical pointing of a 10 GHz signal within a 500 km ground footprint. Alternative uses of the 1 meter inflatable balloon CubeSat are also discussed, such as low cost astronomical galactic plane surveys.
2

Shallow Water Training Range

Reid, Robert 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / During the cold war, undersea warfare (USW) was perceived as a large-area, deep-water operation. The need for USW has recently shifted to the shallow water, littoral environment. Consequently, US naval forces must train to operate in these littoral environments where regional conflicts are most likely to occur. In light of these requirements the Shallow Water Training Range (SWTR) has been initiated. Telemetry is used in the following areas of SWTR: fiber optic, microwave, RF and underwater. Only phase 1 of 8 phases of the program is executing therefore SWTR is a good opportunity for telemetry industry involvement.
3

Ferramenta para modelagem de sistemas de comunicação. / Tool for modeling communication systems.

Zapata, Catalina 06 August 2007 (has links)
Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.
4

Ferramenta para modelagem de sistemas de comunicação. / Tool for modeling communication systems.

Catalina Zapata 06 August 2007 (has links)
Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.
5

Verification of Third Party Components to The Road Telematics Communicator

Mantena, Shanmukha Raju January 2020 (has links)
The Road Telematics Communicator (RTC) as it is called in Scania. It is the device responsible to keep the vehicle connected and send the vehicle data to the off-board system. It uses data from different sources such as GNSS signals, CAN signal, and wireless Telecom signals. Connected vehicles provide real-time information on positioning, fuel consumption, and vehicle diagnostics. There are acceptance and regression test suites that verify the functionality of RTC. Third-party components such as the GNSS module are not a part of the tests due to technical limitations. Hence RTC lacks automated tests for important features. Due to the lack of complete verification in automated test suites, time-consuming tests must be performed on the road. And trouble reports from the field are difficult to analyze. This thesis provides testing the location accuracy of the GNSS module in vehicles used for telematics applications in the automotive industry, by using a GPS vector signal generator in a controlled lab environment. GNSS consists of GPS, GALILEO, GLONASS, BEIDOU. We are using GPS in this research. The GPS receiver is put under test in a controlled lab environment for testing the Time to First Fix, Location accuracy of GPS receiver, and analyzing the performance with the given inputs. Test cases were created similar to field tests on the signal generator. At this stage, an experiment is performed on the GPS receiver which is connected to the signal generator via RF connector and to a computer via LAN. An input data is sent to the signal generator in the form of SCPI commands. The signal generator processes these commands and generates a signal accordingly. This generated signal is fed to the receiver. With the help of a signal generator, we can generate fields like inputs and verify the behavior of the GPS module. By verifying the behavior of the module, we can develop test cases that show the functionality of the receiver.
6

Lecteur radar pour capteurs passifs à transduction radio fréquence / Radar Reader for Radio Frequency Transduction Passive Sensors

Chebila, Franck 31 March 2011 (has links)
Un nouvel axe de recherche sur les réseaux de capteurs a été initié au LAAS par la réalisation de nouveaux capteurs sans fil passifs utilisant une transduction électromagnétique dans la détection de pression et de gaz. Ces capteurs fortement intégrés ne nécessitent aucune alimentation embarquée et leur fréquence de fonctionnement se situe dans la bande de fréquence Ka (26 à 40 GHz). Cette thèse s'inscrit donc dans la conception et la réalisation d'un lecteur adapté à l'interrogation à distance de capteurs à transduction électromagnétique. Son principe de fonctionnement est basé sur une technologie radar de type FMCW. L'avantage principal de la lecture radar des données issues de ce type de capteurs passifs réside dans la possibilité d'avoir des portées de plusieurs dizaines de mètres, bien supérieures à celles classiquement obtenues dans les technologies SAW ou RFID. Dans une première étape est présenté le principe de fonctionnement du lecteur radar et la réalisation de deux prototypes centrés sur les fréquences de 3GHz et 30GHz. Une étude du spectre de la sortie radar, appelé signal de battement radar, est abordée afin de montrer comment les positions et les mesures des capteurs sont lues à distance par ce type de lecteur. Par la suite, un travail d'analyse de la communication sans fil permet de déterminer les paramètres de rétrodiffusion électromagnétique à prendre en compte, tels que les impédances et les fréquences de fonctionnement des capteurs. Ces paramètres sont la base d'une optimisation du système global en termes de sensibilité, de portée radar et des niveaux minimaux de Surface Equivalente Radar (SER) des cibles interrogées. La validation de cette analyse se borne à la mesure de la portée maximale associée à ce type de lecteur et aux différentes mesures de SER de plusieurs types de capteurs dans les bandes de fréquence de 3GHz et 30GHz. Deux principes d'identification de cellules passives sont ensuite présentés. Le premier est basé sur l'utilisation des deux modes de rétrodiffusion de la SER d'un capteur (mode de structure et mode d'antenne) favorisant dans le même temps l'identification sur un mode et la mesure de la grandeur physique sur l'autre, a distance du lecteur. Le deuxième principe utilise le spectre d'un diffuseur multi-bande dont sa SER reconfigurable permet d'associer l'identification de chaque capteur dans un réseau, à la manière d'un code barre. En conclusion, les résultats obtenus dans cette étude valident le principe d'interrogation à longue distance de réseau de capteurs passifs et ouvrent de nouvelles perspectives sur la conception de nouvelles cellules de mesures pour de nouvelles applications dans les secteurs de l'aéronautique, du nucléaire, et de l'environnement. / A new development on sensor networks has been started by LAAS to implement new wireless sensors using passive electromagnetic transduction in the detection of pressure and gas. These highly integrated sensors require no power and the embedded operating frequency is in the Ka band (26 to 40GHz). This thesis is on the design and the realization of a reader suitable for remote sensing of sensor electromagnetic transduction. Its working principle is based on an FMCW radar technology. The main advantage of this radar when reading passive sensors is the ability to have ranges of several tens of meters, much higher than those obtained with conventional SAW or RFID technology. In the first step, the principle of operation of the reader and also the realization of two prototypes focused on the frequencies of 3GHz and 30GHz are presented. A study of the output radar spectrum, called beat signal radar, is discussed to show how the positions and measurements from the sensors are read remotely by the reader. Afterwards, an analysis of the wireless communication is performed to take into account parameters of electromagnetic backscatter such as the impedance and operating frequency of these sensors. These parameters are the basis of an optimization of the global system in terms of sensitivity radar range and the minimal levels of Radar Cross Section (RCS) of the interrogated targets.The validation of this analysis is limited by the reader's maximum range and by various RCS measurements of several types of sensors in the frequency bands of 3GHz and 30GHz. Two principles of sensor passive identification are then presented. The first is based on the simultaneous use of both modes of the sensor's RCS (structural mode and antenna mode), facilitating the identification by one mode and measuring the physical quantity using the other mode. The second principle uses the spectrum of a multiband scatterer where its reconfigurable RCS can associate the identification of each sensor in a network, such as a barcode. In conclusion, the result obtained in this thesis validate the principle of an interrogating network of passive sensors over a long reading range and consequently open a new way of sensor design for future aerospace, nuclear and environment applications.
7

GSM monitorovací systém pro staré lidi / GSM monitoring system for elderly poeple

Ďurík, Maroš January 2014 (has links)
The work deals with design of system for monitoring elderly people. The final product of this thesis will be used to ensure protection of old person´s health. The device will also remind water regime, taking of medicine, measure gas concentration and it will make an emergency call or send an emergency SMS. It will inform an old person about time and date and it will also be working in case of power fail.
8

Threat Modeling and Penetration Testing of a Yanzi IoT-system : A Survey on the Security of the system’s RF communication

Isabar, Diyala January 2021 (has links)
Internet of Thing (IoT) products have in recent years become increasingly popular with both industries and private consumers, and it has been forecasted that the number of connected devices around the world will be roughly 14 billion in the year 2022. One particular field that the booming of IoT solutions continues to create endless possibilities for is smart offices. Several different devices are connected in an office environment to create a better workplace and enable a better, faster and smarter working approach. However, while there are several advantages with IoTs, they have also introduced new security threats that can not be overlooked. In this thesis, the security of a smart office system designed by Yanzi is examined. The system consists of a gateway, 34 sensors and a cloud service embedded as a SaaS. The security analysis was performed in three steps: planning, penetration testing and reporting. Radio frequency (RF) hacking against the systems RF communication was the main focus of the work. Due to some technical issues, not all selected attacks were possible to perform. Out of three that were possible to perform, one of them revealed a security flaw. Different countermeasures for the found flaw were proposed. / ”Internet av saker” produkter har under de senaste åren blivit alltmer populära bland både industrier och privata konsumenter, och man har prognostiserat att antalet anslutna enheter runt om i världen kommer att vara ungefär 14 miljarder år 2022. Ett särskilt område som ökandet av IoT-lösningar fortsätter att skapa oändliga möjligheter för är smarta kontor. Flera olika enheter är anslutna i en kontorsmiljö för att skapa en bättre arbetsplats och möjliggöra ett bättre, snabbare och smartare arbetssätt. Även om det finns flera fördelar med IoT, har de också infört nya säkerhetshot som inte kan förbises. I denna avhandling undersöks säkerheten för ett smart kontorssystem som designats av Yanzi. Systemet består av en gateway, 34 sensorer och en molntjänst inbäddad som en SaaS. Säkerhetsanalysen utfördes i tre steg: planering, penetrationstestning och rapportering. Radiofrekvenshackning mot systemets radiokommunikation var huvudfokus för arbetet. På grund av vissa tekniska problem var det inte möjligt att utföra alla föreslagna attacker. Av de tre som var möjliga att utföra avslöjade en av dem ett säkerhetsfel. Olika motåtgärder för den funna sårbarheten föreslås.

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