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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.
281

Link Budget Maximization for a Mobile-Band Subsurface Wireless Sensor in Challenging Water Utility Environments

See, Chan H., Abd-Alhameed, Raed, Atojoko, Achimugu A., McEwan, Neil J., Excell, Peter S. 06 1900 (has links)
Yes / A subsurface chamber transceiver system and associated propagation channel link budget considerations for an underground wireless sensor system (UWSS) are presented: the application was a sewerage system for a water utility company. The UWSS operates over the GSM850/900, GSM1800/1900 and UMTS bands in order to operate with the standard public mobile phone system. A novel antenna was developed to minimize path loss from the underground location: a folded loop type, which is small enough to fit conveniently inside a utility manhole access chamber while giving adequate signal strength to link to mobile base stations from such a challenging environment. The electromagnetic performance was simulated and measured in both free space and in a real manhole chamber. An experimental test bed was created to determine the return loss and received signal strength with different transceiver positions below the manhole chamber access cover. Both numerical and experimental results suggested an optimum position of the unit inside the manhole, combining easy access for maintenance with viable received signal strength. This confirmed that the characteristics were adequate for incorporation in a transceiver designed to communicate with mobile base stations from underground. A field trial confirmed the successful operation of the system under severe conditions. / This work was supported partially by Yorkshire Innovation Fund, IETG Ltd. Contract, Research Development Project (RDP) and the European Union’s Horizon 2020 research and innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424.
282

Integration of Open-Source Networks

Cooper, Thomas A. 10 May 2012 (has links)
Global System for Mobile Communications (GSM) networks are receiving increasing attention in the open-source community. Open-source software allows for deployment of a mobile cellular network with lower costs, more customization, and scalable control. Two popular projects have emerged that offer varying network architectures and allow users to implement a GSM network in different capacities depending on individual needs. Osmocom provides more network control and scalability but requires commercial Base Transceiver Station (BTS) hardware with limited availability and closed source code. OpenBTS provides minimal GSM network functionality with more easily available and open-source hardware; however, it does not allow multi-cellular network configuration. This thesis offers a significant contribution towards a fully open-source GSM network by integrating the two major open-source communities, Osmocom and OpenBTS. Specifically, the Osmo-USRP program provides an inter-layer interface between the different network architectures of two GSM base station projects. Inter-layer primitive messages are processed in a thread multiplexer that manages logical channels across the interface. Downstream flow control is implemented in order to receive data frames on time for transmitting at the appropriate GSM frame number (FN). Uplink measurements, which are necessary for decision making in the Base Station Controller (BSC), are also gathered in the physical layer of Osmo-USRP and reported to Osmocom. Osmo-USRP operation is tested using a Universal Software Radio Peripheral (USRP), a relatively inexpensive and accessible Software-Defined Radio (SDR). Standard GSM events are investigated for single cell and multi-cellular network configurations. These tests include subscriber authentication and encryption, location updating, International Mobile Subscriber Identity (IMSI) attach and detach, Short Message Service (SMS) storage and delivery, voice calls with the full-rate audio codec, and uplink and downlink measurement reporting. While most functionality is successfully tested, inter-cell handover is not currently implemented. Further details on the proposed implementation of program limitations, especially inter-cell handover, are also discussed. / Master of Science
283

Přenos pacientských informací pomoci GSM / Patient data trasfer over GSM

Pavliš, Jaroslav January 2008 (has links)
This diploma thesis is concerned with possibilities of patient data transfer from a pacemaker or implantable cardioverter-defibrillator to physician over GSM. Theoretical part describes options of data transfer in GSM networks, data appropriate for sending and a structure of message is proposed. A device, that is able to send medical data in a form of SMS messages is designed and constructed. The device uses a Freescale MC68HC908GP32 microcontroller, character display with a Hitachi HD44780 controller and a cell phone Sony CMD-J70. The program for microcontroller is written in assembler for HC08. For tabular view of received messages, an application software for PC was created.
284

Komunikační zařízení přes GSM/GPRS / Communication devices over GSM/GPRS

Prečan, David January 2010 (has links)
This master thesis deals with a data remote transmission by means of SMS and GPRS technology. The overview of current solutions is presented and then a remote temperature measurement and a data transmission employing a communication module GSM/GPRS TM1 through GSM network using GPRS technology is described. As a response to an impulse, the communication module sends SMS. The technical solution is described in details including HW and SW design of the data transfer and processing equipment using a ATmega 162 microprocessor. This equipment communicates with a server (PC), which displays the measured temperature. A prototype which was used for a validation of the design is also described.
285

Efficiency Improvement of RF Energy Transfer by a Modified Voltage Multiplier RF DC Converter

Chaour, Issam 22 March 2021 (has links)
Radio Frequency (RF) energy transfer is getting increasingly importance in new generations of wireless sensor networks and this trend is tremendously supported by the modern trends to Internet of things (IoT). This promising technology enables proactive energy replenishment for wireless devices. With RF energy, transmission long distances between the energy source and the receiver can be overbridged. The main challenge thereby is the power conversion efficiency from a low level RF input power to a Direct Current (DC) voltage which is able to supply the mobile system. For this purpose, a novel approach for RF DC conversion is proposed. It consists of a modified voltage multiplier RF DC converter circuit by incorporating an inductor at the input of the circuit, which generates an induced voltage able to boost the output circuit and improve the conversion efficiency. Analytical analysis of the novel approach has been carried out to determine the optimal value of the inductor to maximize the output power. The experimental investigations show that the proposed solution is able to improve significantly both the output voltage and the power conversion efficiency, compared to the state of the art, and this especially at low input power ranges, which are often the case. At -10 dBm input power, the modified voltage multiplier RF DC converter circuit can reach 1.71 V output voltage and 49.21 % power conversion efficiency for, respectively, 500 kΩ and 10 kΩ resistive loads. In order to validate the new proposal for the RF transfer system experimentally, microstrip meander line antennas and microstrip patch antenna arrays are designed for different ISM bands, where relevant requirements for RF energy transfer are respected. For each antenna a modified voltage multiplier RF DC converter circuit has been applied and the system is tuned to the corresponding resonant frequency to avoid mismatching. In this investigation several scenarios have been addressed, such as RF transmission energy, RF energy harvesting in Global System for Mobile (GSM) bands and Wireless Local Area Networks (WLAN) band are developed. Field test results show high performances of experimental results in comparison to the state of the art.:1 Introduction 2 Theoretical Background 3 State of the Art of RF Energy Transfer 4 Novel Approach for a RF DC Converter Circuit 5 Antennas Design 6 Experimental Verification at Specific Scenarios 7 Conclusion / Die RF-Energieübertragung (RF) gewinnt in neuen Generationen von drahtlosen Sensornetzen zunehmend an Bedeutung. Dieser Trend wird durch das Internet der Dinge (IoT) weiter unterstützt. Diese vielversprechende Technologie ermöglicht eine proaktive Energieversorgung für drahtlose Geräte. Mit RF-Energie können große Entfernungen zwischen der Energiequelle und dem Empfänger überbrückt werden. Die größte Herausforderung dabei ist der Wirkungsgrad, mit dem von einer niedrigen HF-Eingangsleistung in eine Gleichspannung (DC), mit welcher das mobile System versorgt wird, gewandelt wird. Zu diesem Zweck wird ein neuer Ansatz für einen RF-DC-Wandler vorgeschlagen. Er besteht aus einer modifizierten Spannungsvervielfacher-RF-DC-Wandlerschaltung, die eine Spule am Eingang der Schaltung integriert. Diese erzeugt eine induzierte Spannung, die in der Lage ist die Ausgangsschaltung zu verstärken und den Umwandlungswirkungsgrad zu verbessern. Analytische Untersuchungen zu diesem neuartigen Ansatz wurden durchgeführt, um den optimalen Wert der Spule zu bestimmen und die Ausgangsleistung zu maximieren. Die experimentellen Untersuchungen zeigen, dass die vorgeschlagene Lösung in der Lage ist, sowohl die Ausgangsspannung als auch den Wirkungsgrad der Leistungsumwandlung im Vergleich zum Stand der Technik deutlich zu verbessern. Dies gilt besonders für niedrige Eingangsleistungsbereiche, welche häufig vorkommen. Bei -10 dBm Eingangsleistung kann die modifizierte Spannungsvervielfacher-RF-DC-Wandlerschaltung 1.71 V Ausgangsspannung und 49.21 % Leistungswandlungswirkungsgrad für jeweils 500 kΩ und 10 kΩ ohmsche Last erreichen. Um das neue RF-Übertragungssystem experimentell zu validieren, werden Mikrostreifenmäanderlinienantennen und Mikrostreifen-Patch-Antennenarrays für verschiedene ISM-Bänder ausgelegt, wobei die relevanten Anforderungen an die RF-Energieübertragung eingehalten werden. Für jede Antenne wurde eine modifizierte Spannungsvervielfacher-HF-DC-Wandlerschaltung verwendet und das System auf die entsprechende Resonanzfrequenz abgestimmt, um Fehlanpassungen zu vermeiden. Dabei wurden mehrere Szenarien untersucht, wie z.B. RF-Energieübertragung, RF-Energiegewinnung aus GSM-Bändern und WLAN-Netzwerken. Die Feldtests zeigen eine hohe Leistungsfähigkeit der experimentellen Ergebnisse im Vergleich zum Stand der Technik.:1 Introduction 2 Theoretical Background 3 State of the Art of RF Energy Transfer 4 Novel Approach for a RF DC Converter Circuit 5 Antennas Design 6 Experimental Verification at Specific Scenarios 7 Conclusion
286

A direct digital retransmitter based on phase-interpolar direct digital synthesizer and injection locking / Étude d'un émetteur numérique direct RF a base de synthétiseur numérique direct et de verrouillage par injection

Finateu, Thomas 14 November 2008 (has links)
Cette thèse présente un émetteur radio-fréquences, composé d’un synthétiseur numérique de fréquences, lui-même construit autour d’un sigma delta et d’un interpolateur de phase, ainsi que d’un oscillateur verrouillé par injection. Le synthétiseur numérique direct génère des fréquences de 400 à 500 MHz avec une résolution fréquentielle d’au moins 60 Hz. L’oscillateur verrouillé par injection, quand à lui, transpose ces fréquences dans la bande Bluetooth en assurant une multiplication de fréquences par 5. De plus, l’oscillateur verrouillé filtre le bruit de phase du signal d’injection jusqu’à récupérer celui de l’oscillateur libre. La bande passante de l’oscillateur verrouillé par injection peut être programmée numériquement. Cet émetteur a été développée dans une technologie CMOS 65 nm. / This Ph.D dissertation presents a radio-frequency transmitter, made of a direct digital frequency synthesizer, built around a sigma delta and a phase interpolator, and an injection locked oscillator. The direct digital synthesizer generates frequencies between 400 and 500 MHz with a frequency resolution better than 60 Hz. On the other hand, the injection locked oscillator up-converts synthesizer output up to the Bluetooth band by multiplying frequencies by 5. Moreover, the locked oscillator filters injected signal phase noise up to recover the one of the free running oscillator. The locked oscillator bandwidth can be tuned digitally. This transmitter has been developed on 65-nm CMOS technology.
287

A study of Location-Based Services including design and implementation of an enhanced Friend Finder Client with mapping capabilities

Östman, Lennart January 2001 (has links)
Detta arbete behandlar mobilpositionering och relaterade tjänster, så kallade location-based services. Syftet med arbetet är att undersöka hur mobilpositionering kommer att utvecklas i takt med att nya mobilsystem tillåter mer avancerade mobila tjänster. En applikation, Finder Client har utvecklats för att kunna visa vänners positioner på en handdators karta. Kartorna som används finns i färdiga ruttplaneringsprodukter som installeras på handdatorn. Positioneringen sker via en GSM-telefon och SMS. Syftet är även att visa att man kan spara data på handdatorn för att göra intelligentare applikationer. Utvecklingen har gjorts i OPL för en Psion 5mx handdator. OPL är inbyggt i Psion och liknar språk som Pascal och Basic. Slutsatsen är att det går bra att utveckla en Finder klient för handdatorer men det vore mer användarvänligt att utveckla den för en kombinerad handator och mobiltelefon, en så kallad Smart Phone. Man kan också tänka sig att GSM-positionering blir en del av ett ruttplaneringsprogram precis som GPS-positionering är idag. En marknadsundersökning har utförts i examensarbetet. Det kan konstateras att en kombination av GSM- och GPS-positionering kommer troligen att vara lyckosammast i framtiden. De drivande krafterna inom mobilpositionering är den amerikanska statens påbud att alla mobiltelefoner ska kunna positioneras vid alarmsamtal (E911) samt att mobiltelefonoperatörerna ser tjänsterna som en ny potentiell inkomstkälla. Det är mycket svårt att säga vilka tjänster som kommer att bli populära i framtiden. Lösningar som riktar sig till ungdomar, underhållningsbranchen och mot att navigera/spåra fordon ser dock mycket intressanta ut. Det är troligt att positionering kommer att utgöra en liten del i många framtida mobila tjänster. ABSTRACT This work deals with the aspects of location-based services. The aim is to investigate how mobile positioning is going to develop in relation to the fact that new mobile system allows more advanced mobile services. An application, an enhanced Finder Client is developed. It uses maps to display friends’ positions on a handheld computer (PDA). The maps are off-the-shelf route planning products that are installed on the PDA. The positioning is made using a GSM mobile phone and SMS as a means for communication. The aim is also to show that it is possible to store large amounts of data on the PDA to make more intelligent applications. The development is performed in OPL on a Psion 5mx handheld computer. OPL is Psion’s built-in programming language, quite similar to languages like Pascal and Basic. The conclusion is that it is possible to develop a Finder Client for handheld computers but it would be more user-friendly to develop the client on a combined mobile phone and a PDA: a Smart Phone. It can also be possible to incorporate GSM positioning into the map software just as GPS positioning is a part of them today. A market overview has also been performed. The conclusion is that a combination of GSM and GPS positioning is probably the most successful solution for the future. The driving force is the Federal Communications Commissions, FCCs E911 decree, which regulates that all emergency calls from a mobile phone must be able to be positioned. Another aspect is that the mobile operators consider location-based services to be a new source for income. It is difficult to estimate which solutions that are going to be popular in the future. Services focusing on the youth, entertainment and vehicle navigation/tracking seems however to be the most interesting. It is likely to believe that mobile positioning is going to be a small part in many mobile services in the future. / Validerat; 20101217 (root)
288

Rôle de l'interaction enseignant-enfant sur le développement langagier de l'enfant âgé de 5 ans / The influence of teacher-child interaction on the lexical development of five year old children

Mahfoud, Khadija 26 February 2015 (has links)
Les interactions avec les parents jouent un rôle formateur dans le développement et l’apprentissage du langage chez le jeune enfant. En effet, la quantité et le style de langage utilisés par les parents influencent la qualité de l’interaction et par là même la façon dont le langage de leur enfant évolue (Gallaway et Richards, 1999). Toutefois, cette évolution diffère selon les classes sociales et ce dès leur plus jeune âge (avant l’entrée à l’école élémentaire). D’un côté, les enfants de classe favorisée présentent une grande diversité lexicale car ils sont exposés à un discours riche en informations relatives à diverses situations. En revanche, les enfants, issus de classe défavorisée, présentent un retard en ce qui concerne les aptitudes langagières (Hoff, 2003 ; Feldman et al., 2000), car ils sont confrontés à des modèles d’apprentissages moins élaborés. En effet, les années préscolaires sont primordiales pour le développement lexical du jeune enfant d’autant plus, qu’à l’âge de 5 ans, il se prépare à entrer à l’école élémentaire. Il est donc nécessaire d’étudier l’influence de l’environnement scolaire et notamment l’interaction enseignant-enfant sur les performances verbales des enfants dans le but de leur garantir une meilleure intégration scolaire ensuite. Notre intérêt dans cette étude porte donc sur le rôle de l’école maternelle dont l’objectif majeur est la maîtrise du langage oral. Il apparaît opportun de prendre en compte, dans le cadre des apprentissages scolaires, les difficultés ainsi que les compétences de l’enfant pour l’aider à progresser (Florin, 2002). Notre recherche, réalisée auprès d’une population composée de 131 enfants âgés de 5 ans et de leurs 8 enseignantes, vise à comprendre si l’interaction enseignant-enfant a un impact sur les performances verbales des enfants et si cette interaction contribue à réduire les écarts de performances verbales langagières entre les enfants issus de classes sociales favorisée et défavorisée. / Interactions between the parents and the child have positive effects on the development and language learning amongst young children. The quality of interaction with the child is based on the amount and the quantity of the language style used by parents when addressing the child; which seems very important on language development (Gallaway et Richards, 1999).Children stemming from a privileged social class exhibit high lexical diversity. They are exposed to rich discourse information on various situations. Meanwhile, children from a disadvantaged social class are confronted-even before going to school-to different learning models and display a delay regarding language skills compared to their peers (Hoff, 2003 ; Feldman et al., 2000), even though the preschool years are important in the child lexical development. At age 5, the child is getting ready for elementary school, hence the importance of taking into account the influence of school environment, especially the interaction with the teacher on children verbal performance in order to ensure better school integration later.Our interest in this study focuses on the school environment whose major goal is to promote language proficiency, as it is a perquisite for school success. Hence, it seems appropriate to consider, in the context of school learning, the difficulty and the child’s skills in order to help them to progress (Florin, 2002). The main goal of our study, conducted among 131 5-year-old children and their eight teachers, is to underlie the importance of the school environment and particularly the interaction with the teacher on the development of the vocabulary at the preschooler age. Our goal is to determine if the teacher-child interaction has a positive impact on the child's verbal performance, and whether this interaction helps to reduce the gap on verbal achievement between children stemming from privileged and disadvantaged social classes.
289

Handover vertical em redes NGN: integrando a sinalização do domínio de comutação de circuitos e o IMS. / Sem título em inglês

Campacci, Rodrigo Bellotto 18 April 2008 (has links)
Este trabalho visa estudar e implementar a integração entre o domínio de comutação de circuitos e o IP Multimedia Subsystem (IMS) para suportar handovers verticais, ou seja, entre redes de acesso distintas, por exemplo, Global System for Mobile communications (GSM) e WiFi, em especial no Serviço Voice Call Continuity (VCC). Entretanto muito pouco é especificado sobre a integração entre os domínios nas normas das diversas entidades de padronização que tratam sobre o assunto. Assim, apresenta-se uma proposta para essa integração, criando-se uma nova entidade funcional para realizá-la, o Call Data Storage Function (CDSF), que interage com os demais módulos do Serviço VCC e garante que algumas informações que devem ser trocadas entre os módulos não sejam perdidas, devido à conversão de protocolos de sinalização na interface entre tais domínios. O CDSF auxilia também no controle da alocação de endereços de referência utilizados no encaminhamento de chamadas de um domínio para o outro. São definidos os protocolos de acesso ao CDSF, bem como os métodos disponíveis. Em sua concepção, recorre-se a uma modelagem modular, que permite futuras melhorias, apenas por troca de módulos. Como estudos de caso para validar a proposta são apresentados cenários de chamadas que utilizam o Serviço VCC, passando pelo CDSF. Por fim, conclui-se que a integração entre os domínios é viável se a proposta deste trabalho for utilizada. Também se demonstra que a separação dos planos de controle dos planos de dados (de usuário) é uma das contribuições fundamentais da arquitetura NGN para o sucesso de suas implementações, como por exemplo o IMS.Além disso, destacam-se as vantagens que o Serviço VCC pode agregar ao IMS, contribuindo para sua adesão em menor prazo pelas operadoras de telecomunicações, dado que esse serviço contribui para a integração de redes, cada vez mais convergentes, agregando mobilidade e continuidade à sua utilização. / This work intends to study and implement the integration between the circuit switching domain and the IP Multimedia Subsystem (IMS) to support vertical handovers that are between different access networks, such as Global System for Mobile communications (GSM) and WiFi. Therefore the specifications are incomplete about this topic in standards from the entities who works with this subject. Then, is presented a new proposal for this integration: a new functional entity to realize this integration: the Call Data Storage Function (CDSF), which interacts with other modules of VCC Service and guarantees that some information shared between modules are not lost, due to conversion of signalling protocols in the interface between domains. Besides that, CDSF helps in the control of allocation of reference address that are used to route calls from one domain to another. Access protocols to CDSF are defined and CDSF methods are exposed. The CDSF design uses a modular approach, which allows future improvements, just changing modules. As case studies to validate this work proposal, call scenarios are presented that uses the VCC Service, using CDSF. Finally, it is concluded that the integration between domains is viable if this work proposal is used. It is presented, as well, that the separation between control plans and data plans is one of the main contributions of NGN architecture to the success of its implementations, like IMS. Furthermore, it is exposed the advantages that VCC Service can aggregate to IMS, contributing for more rapidly adoption by telecommunications operators, considering that this service helps the networks integration, adding convergence, mobility and continuity.
290

Handover vertical em redes NGN: integrando a sinalização do domínio de comutação de circuitos e o IMS. / Sem título em inglês

Rodrigo Bellotto Campacci 18 April 2008 (has links)
Este trabalho visa estudar e implementar a integração entre o domínio de comutação de circuitos e o IP Multimedia Subsystem (IMS) para suportar handovers verticais, ou seja, entre redes de acesso distintas, por exemplo, Global System for Mobile communications (GSM) e WiFi, em especial no Serviço Voice Call Continuity (VCC). Entretanto muito pouco é especificado sobre a integração entre os domínios nas normas das diversas entidades de padronização que tratam sobre o assunto. Assim, apresenta-se uma proposta para essa integração, criando-se uma nova entidade funcional para realizá-la, o Call Data Storage Function (CDSF), que interage com os demais módulos do Serviço VCC e garante que algumas informações que devem ser trocadas entre os módulos não sejam perdidas, devido à conversão de protocolos de sinalização na interface entre tais domínios. O CDSF auxilia também no controle da alocação de endereços de referência utilizados no encaminhamento de chamadas de um domínio para o outro. São definidos os protocolos de acesso ao CDSF, bem como os métodos disponíveis. Em sua concepção, recorre-se a uma modelagem modular, que permite futuras melhorias, apenas por troca de módulos. Como estudos de caso para validar a proposta são apresentados cenários de chamadas que utilizam o Serviço VCC, passando pelo CDSF. Por fim, conclui-se que a integração entre os domínios é viável se a proposta deste trabalho for utilizada. Também se demonstra que a separação dos planos de controle dos planos de dados (de usuário) é uma das contribuições fundamentais da arquitetura NGN para o sucesso de suas implementações, como por exemplo o IMS.Além disso, destacam-se as vantagens que o Serviço VCC pode agregar ao IMS, contribuindo para sua adesão em menor prazo pelas operadoras de telecomunicações, dado que esse serviço contribui para a integração de redes, cada vez mais convergentes, agregando mobilidade e continuidade à sua utilização. / This work intends to study and implement the integration between the circuit switching domain and the IP Multimedia Subsystem (IMS) to support vertical handovers that are between different access networks, such as Global System for Mobile communications (GSM) and WiFi. Therefore the specifications are incomplete about this topic in standards from the entities who works with this subject. Then, is presented a new proposal for this integration: a new functional entity to realize this integration: the Call Data Storage Function (CDSF), which interacts with other modules of VCC Service and guarantees that some information shared between modules are not lost, due to conversion of signalling protocols in the interface between domains. Besides that, CDSF helps in the control of allocation of reference address that are used to route calls from one domain to another. Access protocols to CDSF are defined and CDSF methods are exposed. The CDSF design uses a modular approach, which allows future improvements, just changing modules. As case studies to validate this work proposal, call scenarios are presented that uses the VCC Service, using CDSF. Finally, it is concluded that the integration between domains is viable if this work proposal is used. It is presented, as well, that the separation between control plans and data plans is one of the main contributions of NGN architecture to the success of its implementations, like IMS. Furthermore, it is exposed the advantages that VCC Service can aggregate to IMS, contributing for more rapidly adoption by telecommunications operators, considering that this service helps the networks integration, adding convergence, mobility and continuity.

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