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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.
171

Contribución al desarrollo de un entorno seguro de m-commerce

Ponce Vásquez, Diego Arturo 02 July 2002 (has links)
La exitosa implantación de la telefonía móvil a escala mundial presenta una muy importante oportunidad para la expansión del comercio electrónico sobre entornos inalámbricos. El comercio electrónico para móviles, m-Commerce, implica tres aspectos básicos: 1) la negociación y el servicio en la vecindad de cliente, 2) información oportuna y georeferenciada mientras el usuario esta en movimiento, 3) la posibilidad para completar una transacción en cualquier sitio y momento. El usuario debe tener las facilidades siguientes: la negociación y la entrega inmediata, métodos rápidos de micro y de macro pago, y facilidad de uso en el ambiente de móvil. Una de las novedades del comercio móvil es la posibilidad de atraer a clientes en el vecindario hacia un centro de venta y/o servicios proporcionándoles la información apropiada. Existen, sin embargo, una serie de factores que dificultan la implantación y el desarrollo del comercio móvil respecto al comercio electrónico. Esos inconvenientes se relacionan con las características del ambiente inalámbrico: normalmente menor ancho de banda, latencia más baja, menos estabilidad de conexiones, la disponibilidad menos previsible. Y las limitaciones en los equipos móviles: la unidad de procesamiento central menos potente, menos memoria, limitaciones en el consumo de potencia, formato reducido de pantalla, y otras más.La seguridad extremo a extremo entre el servidor de Internet y el terminal móvil es indispensable para aplicaciones de comercio electrónico. La especificación de la capa de seguridad WTLS (Wireless Transport Layer Security de WAP) no proporciona este nivel de seguridad. El uso de WTLS y la seguridad a nivel de la capa de transporte TLS (Transport Layer Security) permite la privacidad en los canales inalámbrico e Internet, pero la seguridad alcanzada no es suficiente para aplicaciones de comercio electrónico; por ello se precisan mecanismos de seguridad extremo a extremo. En esta tesis se propone una alternativa a la arquitectura de la seguridad de WAP para resolver el problema mencionado, basada en la implementación de una capa de seguridad nueva dentro de la capa WAE (Wireless Application Environment). Esto hace posible la seguridad extremo a extremo, compatibilidad con TLS, transparencia ante el usuario, y se evita la traducción y descompresión en la pasarela de WAP. Varios estudios sobre usabilidad de los dispositivos con capacidades de WAP indican que los usuarios se desconectaron debido a tiempos de respuesta lentos y la falta de comodidad en el uso (interfaces no agradables, servicios costosos, . ). Los estudios coincidieron en que las velocidades más rápidas y el uso extendido de equipos móviles de datos promueven el comercio móvil, y que el número de usuarios familiarizados con equipos móviles sube constantemente, particularmente entre usuarios de WAP, de modo que estos usuarios comienzan a ver sus teléfonos móviles como algo más que meros teléfonos. La movilidad del usuario contribuye a hacer las redes inalámbricas más complejas, y constituyen los nuevos paradigmas en el intercambio de información. Las posibilidades que se abren para la Internet inalámbrica constituyen una oportunidad importante para el comercio electrónico. El futuro e impacto social de las tecnologías utilizadas, WAP, GPRS, UMTS, . son cuestionadas habitualmente. En esta tesis se analiza la posibilidad de realizar operaciones de m-Commerce sobre WAP. Por ello, se presentan los mecanismos de seguridad de WTLS (Wireless Transport Layer Security) y se analiza la seguridad extremo a extremo en este protocolo. En redes inalámbricas, existe la necesidad de acelerar la respuesta al usuario, facilitarle el uso en ambientes ruidosos, con desconexión no previsible, sobre dispositivos con formato limitado. Para paliar los problemas relacionados a la entrega de información, facilitar el uso y personalizar el servicio con el cliente, se presenta una propuesta basada en un sistema intermediario. Los objetivos de dicho intermediario son a) reducir el tráfico de datos en el canal inalámbrico delegando tareas tales como la búsqueda, interacción y filtrado de la información al Intermediario aún estando fuera de línea; b) Reutilizar contenidos: reutilizar la información residente en el almacén intermedio mediante un sistema distribuido de caches y proxies; c) Personalizar la información: conociendo previamente el perfil del usuario se puede filtrar y distribuir información en forma predictiva y d) Gestionar la información del estado de los certificados con OCSP (On-line Certificate Status Protocol).
172

End-to-End Application Billing in 3G / End-to-End Application Billing in 3G

Chaudry, Kashif, Karadza, Elma January 2002 (has links)
We have 3G on the doorstep but nothing seems to attract ordinary people to this technology. To attract the mass market the telecom industry must show something beyond high bit rates. They must show how ordinary people can take advantage of this new technology. This is done by showing the possibilities of the new technology and by demonstrating applications that it will handle. The telecom industry must convince the telecom operators to invest in this technology and the only thing that matters to them is how much revenue they can make by adopting the upcoming technology. To convince the operators industry must show how the operators can charge for the new types of applications that will be introduced soon. This is the main reason why this Master's Thesis has been conducted. The purpose of this thesis is to provide a demonstration to Ericsson's 3G lab in Katrineholm in the form of an IP application with a billing solution. This thesis describes the migration from 1G to 3G and examines existing and future billing strategies as well. The IP application is an application that uses progressive streaming in order to stream multimedia content to a PDA connected to a 3G phone. This application is platform independent because it is placed on leading Web servers, Apache and IIS. The billing application consists of a number of steps. The first step is logging, which is performed by the Web server on which the streaming application is placed. The second step, processing and billing, is performed in the BGw, which is Ericsson's mediation tool, and the SQL server.The third step is displaying the bill, which is done by using ASP to create an active HTML page.
173

Internal Wideband Mobile Phone Antenna for UMTS/WLAN/WiMAX Wireless Communication System

Su, Wei-Cheng 26 May 2006 (has links)
In this thesis, the study mainly focuses on the current trends in development of compact multi-media mobile phone and provides a wideband monopole antenna design suitable for application in wireless communicating system in the near future. By utilizing the planar monopole antenna structure, the proposed antenna design is easy to be embedded into the mobile phone. Further, by using a shielding metal cover, we create a zone with low surface current distribution. This effect will reduce the electromagnetic coupling between the antenna and the electronic elements and make it possible to integrate more related elements into the mobile phones. Finally, we use the simulation software to analyze the dielectric effect caused by the casing of mobile phone and human body on the proposed antenna.
174

Architecture réseau pour véhicule de transport en commun communiquant

Bertaux, Lionel 26 September 2013 (has links) (PDF)
Avec la démocratisation des appareils mobiles, les transports en commun sont amenés à proposer de nouveaux services à leur usagers et notamment une connexion à Internet. Le véhicule de transport en commun agit alors comme un routeur mobile fournissant une connexion fiable à ses noeuds et doit pour cela être connecté en permanence à un point d'accès. Les zones de couverture étant limitées par les technologies utilisées et par les obstacles, des changements de réseaux sont alors nécessaires et provoquant différents évènements pouvant impacter les performances des protocoles de Transport : introduction de latences dues à la configuration des interfaces, modification des caractéristiques du chemin utilisé par la communication.. Dans cette thèse nous étudions cet impact en déterminant son origine puis nous proposons des solutions visant à le réduire de deux manières : en réduisant les latences introduites par le changement de réseau et en diminuant l'impact de la modification des caractéristiques du réseau.
175

Βελτιστοποίηση της ποιότητας παρεχομένων υπηρεσιών σε διαλειπτικά κανάλια (fading channels) για δίκτυα κυτταρικής κινητής τηλεφωνίας τρίτης γενιάς

Κολέττι, Θεοχάρης - Αλέξανδρος 11 January 2011 (has links)
Αντικείμενο της παρούσας διπλωματικής εργασίας είναι η μελέτη των μεθόδων βελτιστοποίησης της ποιότητας των παρεχομένων υπηρεσιών των δικτύων κυτταρικής τηλεφωνίας τρίτης γενιάς σε διαλειπτικό περιβάλλον. Αρχικά γίνεται μια σύντομη ιστορική αναδρομή στην εξέλιξη των συστημάτων κινητών επικοινωνιών και παρουσιάζεται το σημαντικότερο πρότυπο τρίτης γενιάς, το UMTS και τα ιδιαίτερα τεχνικά χαρακτηριστικά του. Στην συνέχεια αναλύεται το LTE το οποίο αποτελεί την τελευταία εξέλιξη των δικτύων τρίτης γενιάς και αναμένεται να αντικαταστήσει το UMTS στο άμεσο μέλλον αποτελώντας στην πραγματικότητα τον πρόδρομο των συστημάτων τέταρτης γενιάς. Στην συνέχεια εστιάζουμε στα διαλειπτικά κανάλια αναλύοντας τα φαινόμενα που παρατηρούνται σε αυτά και τα στατιστικά μοντέλα μέσα από τα οποία περιγράφονται. Παράλληλα διερευνάται η επίδραση των φαινομένων αυτών (θετική ή αρνητική) στο QoS των δικτύων τρίτης γενιάς βάσει των χαρακτηριστικών τους (όπως παρουσιάστηκαν στο κεφάλαιο 1) και οι δυνατότητες για περαιτέρω βελτιστοποίηση κατα τον σχεδιασμό των δικτύων και την σωστή εκμετάλλευση των χαρακτηριστικών του περιβάλλοντος όδευσης. Ιδιαίτερη αναφορά γίνεται στα μοντέλα εσωτερικού χώρου λόγω του μεγάλου φορτίου κίνησης που καλούνται να εξυπηρετήσουν. Στο τελευταίο μέρος παρουσιάζεται η διαδικασία παραμετροποίησης κάποιων σημαντικών μοντέλων και τα αποτελέσματα των εξομοιώσεων που έγιναν στον χώρο του κτηρίου των Ηλεκτρολόγων Μηχανικών. / The subject of this diploma thesis is the study of the optimization techniques of the quality of service for third generation cellular telephony networks in fading enviroment. After a short presentation of the evolution of the systems of wireless telecommunications, it is discussed UMTS the most important third generation system which dominated the european market and its technical features. LTE is also introduced, the system which is expected to replace UMTS in the near future while being the predecessor of the fourth generation systems. Then we focus on the fading channels analysing the phenomena wich are related to them and analysing the statistical models that describe them. It is also studied the effect (positive or negative) of these phenomena on the QoS of the third generation networks and the optimization methods which can be applied during the network designing process with special reference to the indoor propagation models because of the big amount of traffic load that they are asked to serve. At the last chapter of the thesis there is a presentation of the parameter setting procedure for some important models and the outcomes of the simulation that took place in the building of Electronic Engineering.
176

Assessment of value creation in private equity: the acquisition of Burger King by 3G Capital

Hoene, Daniel Jobst Elmar 29 January 2016 (has links)
Submitted by Daniel Hoene (daniel-hoene@gmx.de) on 2016-03-17T02:11:14Z No. of bitstreams: 1 Daniel Hoene.pdf: 1204800 bytes, checksum: 80727c04207d47b288a6fb755cda7a16 (MD5) / Rejected by Janete de Oliveira Feitosa (janete.feitosa@fgv.br), reason: Sr. Daniel, boa tarde. Solicitamos nova submissão digital pois na submissão feita não consta a Folha de Assinatura da Banca da defesa. O impresso entregue na Secretaria está correto. Não há necessidade de nova impressa. Aguardamos novo contato quando o senhor tiver feito a nova submissão. Cordialmente, Janete on 2016-04-12T19:41:22Z (GMT) / Submitted by Daniel Hoene (daniel-hoene@gmx.de) on 2016-04-13T21:48:35Z No. of bitstreams: 1 Thesis - Daniel Hoene.pdf: 1513393 bytes, checksum: e3291314873d496efd62f42557f5473f (MD5) / Approved for entry into archive by Janete de Oliveira Feitosa (janete.feitosa@fgv.br) on 2016-04-14T20:03:26Z (GMT) No. of bitstreams: 1 Thesis - Daniel Hoene.pdf: 1513393 bytes, checksum: e3291314873d496efd62f42557f5473f (MD5) / Approved for entry into archive by Maria Almeida (maria.socorro@fgv.br) on 2016-05-09T12:30:31Z (GMT) No. of bitstreams: 1 Thesis - Daniel Hoene.pdf: 1513393 bytes, checksum: e3291314873d496efd62f42557f5473f (MD5) / Made available in DSpace on 2016-05-09T12:34:00Z (GMT). No. of bitstreams: 1 Thesis - Daniel Hoene.pdf: 1513393 bytes, checksum: e3291314873d496efd62f42557f5473f (MD5) Previous issue date: 2016-01-29 / This thesis elaborates the creation of value in private equity and in particular analyzes value creation in 3G Capital’s acquisition of Burger King. In this sense, a specific model is applied that composes value creation into several drivers, in order to answer the question of how value creation can be addressed in private equity investments. Although previous research by Achleitner et al. (2010) introduced a specific model that addresses value creation in private equity, the respective model was neither applied to an individual company, nor linked to indirect drivers that explain the dynamics and rationales for the creation of value. In turn this paper applies the quantitative model to an ongoing private equity investment and thereby provides different extensions to turn the model into a better forecasting model for ongoing investments, instead of only analyzing a deal that has already been divested from an ex post perspective. The chosen research approach is a case study about the Burger King buyout that first includes an extensive review about the current status of academic literature, second a quantitative calculation and qualitative interpretation of different direct value drivers, third a qualitative breakdown of indirect drivers, and lastly a recapitulating discussion about value creation and value drivers. Presenting a very successful private equity investment and elaborately demonstrating the dynamics and mechanisms that drive value creation in this case, provides important implications for other private equity firms as well as public firms in order to develop their proprietary approach towards value creation.
177

Performance Evaluation Of Self-Backhaul For Small-Cell 5G Solutions

Hellkvist, Martin January 2018 (has links)
This thesis evaluates the possibility of using millimeter waves of frequency 28GHz for the use of wireless backhaul in small cell solutions in the coming fifth generation mobile networks. This frequency band has not been used in preceding mobile networks but is undergoing a lot of research. In this thesis simulations are performed to evaluate how the high frequency waves behave inside a three dimensional grid of buildings. The simulations use highly directive antenna arrays with antenna gains of 26dBi. A main results of the investigation was that a high bandwidth of 800MHz was not enough to provide 12Gbps in non line-of-sight propagation within the simulations. Furthermore, without interference limiting techniques, the interference is probable to dominate the noise, even though the high diffraction losses of millimeter waves propose that interference should be very limited in urban areas.
178

Modernización de la red de acceso de un operador móvil para el caso de Lima Metropolitana

Otárola Correa, Diego Antonio, Campos Gonzales, Frank January 2015 (has links)
La presente tesina titulada “Modernización de la red de acceso de un operador móvil para el caso de Lima Metropolitana” expone una propuesta para un operador que tiene como objetivo poder incrementar su cobertura de servicio de segunda y cuarta generación, para esto se definen conceptos teóricos en base a lo que son las tecnologías de telefonía móvil celular de tipo GSM, UMTS y LTE y se compararan con las características técnicas de los equipos que se plantean usar demostrándose que estos pueden optimizar la red de acceso del operador en cobertura y funcionamiento para brindar un mejor servicio en base a 2G y 4G. Para lograr el objetivo propuesto, esta tesina describe el diseño y dimensionamiento de proyecto, pasos para su ejecución, especificaciones técnicas de los equipos, procedimiento para la puesta en servicio y resultados en base a pruebas del servicio y KPI. The current thesis entitled “Modernización de la red de acceso de un operador móvil para el caso de Lima Metropolitana” exposes a proposal for a mobile operator that has as a target increase their second and fourth generator coverage. For achieve this we have to defined theoric concepts based on the mobile telecommunication technology GSM, UMTS and LTE and compare with the features of equipment proposed to use proving that the coverage and performance of the access network of the operator can be improved for provide a better 2G and 4G service. For achieve this target proposed, this thesis describes the design and sizing of Project, steps for execution, technical features of equipment, on air procedure and results base on the testing service and KPI.
179

A gestão das competências organizacionais em empresas da cadeia de valor para provimento de telefonia celular de 3ª geração (3G). / Organizational competencies management in the value chain for providing 3ª genneration celular telephone services (G3).

Sandro Marcio da Silva 04 July 2002 (has links)
A tese teve como objetivo analisar os processos de desenvolvimento e compartilhamento intra-empresarial de competências organizacionais. Foi analisada a relação entre a Telemig Celular e as empresas que com ela compunham, em junho de 2002, a cadeia de valor para provimento de serviços de telefonia celular. O desenvolvimento das competências organizacionais foi analisado à luz da perspectiva de oferta dos serviços de 3G. A Telemig Celular foi analisada por meio de entrevistas e um workshop junto ao corpo gerencial. As demais empresas da cadeia foram abordadas via entrevistas junto às gerências de RH e estratégia. A utilização do modelo de Fransman mostrou que as relações entre as empresas ainda não constituem efetivas parcerias. Os elos mais forte da cadeia – indústria de equipamentos, baseada no domínio tecnológico, e operadoras, baseadas no acesso ao usuário final - têm liderado as decisões mais importantes da cadeia. Observou-se que o desenvolvimento das competências organizacionais é mais estruturado na camada 1, em que há claras regras de desenvolvimento e proteção das competências, além de diretrizes e alocação de recursos para a realização de pesquisas. Também os investimentos em RH são existentes e mais conectados com a estratégia organizacional. Nas demais empresas da cadeia encontraram-se áreas de RH reduzidas, quando existentes, e que adotam práticas e políticas de gestão tradicionais. A pesquisa mostrou que falta às empresas e, principalmente, ao RH uma visão integrada de negócios e cadeia de valor, o que tem levado à subordinação das empresas brasileiras e menores às empresas multinacionais e maiores. / This paper aimed to analyze the processes of development and intra-company sharing of organizational competencies. It looked at the relationship between Telemig Celular company and its counterparts making up the value chain in June 2002 for providing cellular telephone services. The organizational competency development was considered in the light of the 3G-service supply perspective. Telemig Celular was analyzed through interviews and a workshop with its managers. The other companies in the chain were approached through interviews with their strategy and HR managements. By using Fransman's model it was shown that the company relationships are not effective partnerships yet. The strongest links in the chain —equipment industry relying on their technological supremacy, and carriers relying on end user access— have been taking the chain's most important decisions. The development of organizational competencies was observed to be more structured in layer 1, where there are clear development rules and competency protection, as well as guidelines and fund allocation for research. Also, HR investments are present, and they are more connected to organizational strategy. In the rest of the chain companies, the research found small HR areas, if any, adopting traditional management practices and policies. And it showed that companies, mainly their HR, lack an integrated view of business and value chain, which has been leading to the subordination of the Brazilian and smaller companies to the multinational and larger ones.
180

CU2 : Design av ett PDA-baserat diskussionverktyg med ljud/bildkommunikation / CU2

Andersson, Eskil, Akrawi, Sirvan January 2001 (has links)
I detta arbete framlägger vi ett designförslag på hur ett diskussionsverktyg som stödjer ljud- och bildkommunikation kan se ut. Ett förslag som förbättrar och förenklar den distanskommunikation som idag sker med hjälp av mobiltelefoner, videokonferenssystem samt webbkameror anslutna till persondatorer. Den design vi föreslår möjliggör för mobila användare att visuellt föra flerpartssamtal med hjälp av PDA:er. Vårt designförslag har fått arbetsnamnet CU2 (see you too) och är tänkt att fungera i tredje och/eller fjärde generationens mobila nät. Vi har valt att genomföra vårt magisterarbete på företaget A Brand New World i Kista, Stockholm. Företaget utvecklar och säljer system inom mobilt Internet. / Eskil Andersson, A Brand New World, Kista, 08-4779875 Sirvan Akrawi, A Brand New World, Kista, 08-4779853

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