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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.
21

Mobiliojo tinklo paslaugų kokybės vertinimo ir gerinimo būdų tyrimas / Investigation of evaluation and improvement methods of service quality in mobile networks

Batkauskas, Vaidas 27 June 2006 (has links)
Topicality of the problem. GSM mobile networks are very widely used in the world and the number of GSM users exceeds 10^9. In the last decade, the GSM/GPRS network has been very rapidly expanded in Lithuania as well. Coverage of the network has reached 99 % of territory of the country. Load of the network in largest cities reaches up to several hundred Erlangs for square kilometre. Voice traffic still generates the largest part of the network load, however mobile data traffic also grows rapidly. Radio interface between the user of mobile services and the network is not stationary. The received QoS of every user in different places is different. Even in a single cell, radio link characteristics differ in different parts of the cell. The signal level may easily vary about 10–20 dB just within several or tens of meters. Moreover, a mobile user experiences different link conditions while moving in the natural environment within or between cells. However, historically characteristics of QoS of mobile services are measured and evaluated like the ones of the fixed network using statistical methods. Statistically calculated characteristics of QoS do not include information about the received quality of mobile telecommunication services of every individual user. Conception of the received quality of services of individual users (individual QoS – iQoS) in the GSM/GPRS network has not been analysed in the world before. QoS should be measured not only at the network level, as it is... [to full text]
22

Mobiliojo tinklo paslaugų kokybės vertinimo ir gerinimo būdų tyrimas / Investigation of evaluation and improvement methods of service quality in mobile networks

Batkauskas, Vaidas 27 June 2006 (has links)
Topicality of the problem. GSM mobile networks are very widely used in the world and the number of GSM users exceeds 10^9. In the last decade, the GSM/GPRS network has been very rapidly expanded in Lithuania as well. Coverage of the network has reached 99 % of territory of the country. Load of the network in largest cities reaches up to several hundred Erlangs for square kilometre. Voice traffic still generates the largest part of the network load, however mobile data traffic also grows rapidly. Radio interface between the user of mobile services and the network is not stationary. The received QoS of every user in different places is different. Even in a single cell, radio link characteristics differ in different parts of the cell. The signal level may easily vary about 10–20 dB just within several or tens of meters. Moreover, a mobile user experiences different link conditions while moving in the natural environment within or between cells. However, historically characteristics of QoS of mobile services are measured and evaluated like the ones of the fixed network using statistical methods. Statistically calculated characteristics of QoS do not include information about the received quality of mobile telecommunication services of every individual user. Conception of the received quality of services of individual users (individual QoS – iQoS) in the GSM/GPRS network has not been analysed in the world before. QoS should be measured not only at the network level, as it is... [to full text]
23

Um framework para controle distribuído de ambientes e dispositivos

Oliveira, Luís Eduardo Melo Corrêa de 31 January 2008 (has links)
Made available in DSpace on 2014-06-12T15:51:59Z (GMT). No. of bitstreams: 1 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Tradicionalmente, soluções para controle e automação de ambientes são providas por um fornecedor, utilizando um padrão de comunicação quase sempre fechado e de alto custo. Além disso, muitas destas soluções oferecem alternativas limitadas de controle. A possibilidade de gerenciar ambientes através de diversas tecnologias simultaneamente contribuirá para o aumento do conforto, segurança e qualidade de vida dos usuários, tornando-se um ponto crucial para uma maior difusão da automação doméstica. Entre as vantagens de um ambiente automatizado pode-se citar a contribuição para o processo de inclusão digital dos portadores de necessidades especiais e/ou idosos. O trabalho em questão consiste na proposta de um framework para controle de ambientes e dispositivos distribuídos envolvendo tecnologias como: UPnP, Web Services, Comandos de voz e GPRS dentre outras. Com o objetivo de atender a esses requisitos, foram desenvolvidos módulos e aplicações em Java® e .Net® para serem executados num servidor e em dispositivos móveis e sistemas embarcados
24

O uso do EDGE nos sistemas celulares em direção à 3ª geração

Santana Aguiar, Elisangela January 2002 (has links)
Made available in DSpace on 2014-06-12T15:59:19Z (GMT). No. of bitstreams: 2 arquivo5031_1.pdf: 3343228 bytes, checksum: 5473b22f6502ccef2e12e259b590641d (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2002 / Atualmente o mercado das comunicações móveis está sendo dirigido pela necessidade dos serviços de dados. Entre os sistemas da primeira e segunda geração (1G e 2G), o GSM (Global System Mobile) é indiscutivelmente o mais utilizado no mundo para aplicações de voz, porém, continua oferecendo serviços de dados com baixas taxas de transmissão, as quais em paralelo com as baixas capacidades dos sistemas, são os principais problemas do progresso da multimídia móvel. Além disso, os serviços de dados são caracterizados pela necessidade de grandes larguras de banda. Sendo assim, o GSM que originalmente foi desenvolvido para transmissão de voz e serviços de dados com baixas taxas, está rapidamente sendo atualizado para incorporar novos serviços multimídia. Na sua geração intermediária 2,5G, com o HSCSD (High Speed Circuit Switching Service Data) e o GPRS (General Packet Radio Service), possuirão suas taxas de dados aumentadas em três vezes com a introdução de suas versões melhoradas, ECSD (Enhanced Circuit Switched Data) e EGPRS (Enhanced GPRS), juntos esses dois sistemas são denominados de EDGE (Enhanced Data Rate for Global Evolution). O EDGE utilizará uma modulação de alto nível denominada 8PSK (8 Phase Shift Keying) em conjunto com a GMSK (Gaussian Minimum Shift Keying), utilizada pelo GPRS, também usará esquemas de codificação mais eficientes e mecanismos de controle de qualidade do link, IR (Incremental Redundancy) e LA (Link Adaptation), os quais trazem benefícios quando utilizados em boas condições de propagação. Este trabalho trata da evolução dos serviços de dados, em especial da 2,5G, concentrando-se no estudo do EDGE, mais especificamente do EGPRS, com a abordagem dos seus principais aspectos e características. Foram realizados estudos considerando as alocações single e multislot, suas especificações, para a transmissão de diferentes modelos de dados, Funet, Railway e Mobitex, entre PCU (Packet Control Unit) e MSs (Mobile Stations). Desenvolveu-se um protótipo com o objetivo de simular esse nível de abstração e testar um algoritmo para a otimização das alocações, de forma a permitir o melhor estudo e a análise do desempenho do sistema
25

Sistema digital de medição direta da flecha em linhas de transmissão com o uso de sensores ópticos e comunicação via tecnologia GPRS / Digital system of direct mensuration of the arrow in lines of transmission with the use of sensor optical and communication through tecnology GPRS

Severino, Juciléia Filomena Barbosa 07 March 2006 (has links)
Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-02-09T14:36:04Z No. of bitstreams: 1 jucileiafilomenabarbosaseverino.pdf: 3316615 bytes, checksum: df15a3f5f322e0fdf958a0d7258aa19c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-02-10T10:39:25Z (GMT) No. of bitstreams: 1 jucileiafilomenabarbosaseverino.pdf: 3316615 bytes, checksum: df15a3f5f322e0fdf958a0d7258aa19c (MD5) / Made available in DSpace on 2017-02-10T10:39:26Z (GMT). No. of bitstreams: 1 jucileiafilomenabarbosaseverino.pdf: 3316615 bytes, checksum: df15a3f5f322e0fdf958a0d7258aa19c (MD5) Previous issue date: 2006-03-07 / A necessidade de se aumentar o transporte de energia nas já instaladas linhas de transmissão, sem que para isso tenha-se que modificar as mesmas, tem motivado a elaboração de diversos estudos relativos a ampacidade de LTs. Com o objetivo de obedecer aos critérios estabelecidos em normas de segurança, as concessionárias de energia adotavam, e muitas vezes ainda adotam, os estudos estatísticos já elaborados sobre o afundamento dos cabos quanto da passagem de corrente por eles. Estes estudos, entretanto, mesmo sendo relativamente eficientes em algumas situações climáticas, não representam o valor real da Flecha e, portanto, superestimam o valor do afundamento, prejudicando o aumento do fluxo de potência. Desta maneira tem-se investido em monitoramento em tempo real para estabelecer novos limites de carregamento das LTs. A presente dissertação apresenta uma nova proposta de monitoramento em tempo real de LTs. O sistema proposto baseia-se na emissão de um feixe de laser alocado sobre a LT e recepção do mesmo através de sensores ópticos instalados em um painel sensor localizado em uma das torres da linha. O processamento da informação colhida pelo sistema proposto será feito em uma unidade remota, sendo a informação transportada até ela com o uso da tecnologia de comunicação GPRS. / The necessity to increase the transport of energy in the installed transmission lines, without modifying them, it has motivated the elaborations of several studies of the ampacity of TLs. Aiming to fulfill the approaches established in safety norms, energy concessionaries have adapted previous well-known statistical studies of cable’s sag. However those studies don't represent the real value of the sag and, therefore they overestimate the value of the sag harming the flow potency. That being so, there has been investment in real time monitoring to establish new limits of shipment of TLs. This dissertation presents a new proposition of a real time monitor of TL. The proposed system is based on the emission of a laser allocated on the TL and reception of the same through sensors optical installed in a sensor panel located in one of the towers of the line. The processing of the information collected through that system will be made in a remote unit and information will be driven to it using the GPRS communication technology.
26

En utvärdering av fastighetsskötares användande av ett mobilt arbetsordersystem

Magnusson, Veronika, Lindström, Anna January 2002 (has links)
När ett nytt system kommer i användning så är det viktigt att följa upp utifall systemet fyller sin funktion och är användbart. Enovation i Karlskrona har utvecklat ett mobilt arbetsordersystem till fastighetsskötarna på fastighetsbolaget Gallionen. Det är det systemet som vi har utvärderat i detta arbete. Anledningarna till att systemet har utvecklats är många. Den viktigaste anledningen är att fastighetsskötarna ska slippa åka fram och tillbaka till receptionen för att hämta nya arbetsordrar och slippa ha med sig en massa papper. De har nu också fått en bättre överblick över sitt eget arbete och över vad de andra fastighetsskötarnas gör under sin arbetsdag. Vi har fokuserat på att först och främst avgöra om systemet verkligen underlättar fastighetsskötarnas arbetsdag eller om det tvärtom försvårat deras arbete. Vi har sedan valt att jämföra användandet av systemet med hur det var innan systemet kom i användning, och vilka för- och nackdelar som finns med systemet och det tidigare arbetssättet. Vi har till sist tagit upp nya funktioner och förändringar som vi efter våra undersökningar kommit fram till skulle kunna vara lämpliga. Vi har själva inte kunnat bestämma vårt urval, eftersom det enbart är Gallionens tre manliga fastighetsskötare som använder systemet. Vi började med att intervjua dem en och en och kompletterade sedan genom att följa med dem under en arbetsdag för observation. Till sist utförde vi ett självtest där vi själva testade systemet och fick flera förslag till nya funktioner och ändringar. Om tekniska problem bortses, kan vi säga att användandet av systemet fungerar bra. Eftersom fastighetsskötarna fortfarande använder det gamla sättet att arbeta på parallellt med arbetsordersystemet, är det svårt att säga hur mycket inverkan arbetsordersystemet har i fastighetsskötarnas arbete. Vi har kommit fram till att systemet i allra högsta grad har underlättat fastighetsskötarnas arbetsdag. Det är enkelt att lära sig, det är lätt att förstå och det är nästan precis som fastighetsskötarna vill ha det. Vi tror på systemet som ett hjälpmedel, men vi har svårt att förstå varför ett företag med tre användare har valt att introducera systemet. Vi har under vårt arbete kommit fram till att systemet på flera sätt skulle vara mer användbart i ett större företag där fler personer är inblandade. / It is important to follow up, whether a system is full functionable and useable, when a new system is being introduced. Enovation in Karlskrona has developed a mobile workorder system to the janitors of the real estate company Gallionen. We have been evaluating this system with this paper. There are many reasons why the system was developed. The most important, was that the janitors wouldn?t have to drive back and forth to the reception to get new workorders. They could also get away from bringing a lot of papers. They would now have a better overview about their own and the other janitors work during a workday. We have first and foremost been focused whether the system really makes the janitors workday more easy. We decided then to compare the current system with how it worked before it came in use and which advantages and disadvantages that comes with the system and the earlier way of working. At last we have been talking about some new functions and changes that we after our investigations have found very appropriate for the system. We have not been able to decide the selection by our selves, because the only user of the system is three male janitors. We first interviewed the janitors one by one, and complemented the results by observing them a half workday. Finally we performed a test of the system by our own where we received a lot of proposals of new functions and changes. If technical problems can be ignored, the useability of the system are great in the highest degree. It is hard to say how much influence the work order system has had in the janitos work, since the janitors still uses the old way to work by in parallel with the new system. We have come to the conclusion that the system in the highest degree have facilitate the janitors working day. It is easy to learn, easy to understand and it works almost totally accordning to the janitors desire. We believe in the system as an aid, but we find it rather hard to understand why a company with onlu three users has choosen to introduce the system. We think that the system will be more useful in a company with more persons involved. / Veronika Magnusson Blasius Königsgatan 18 A 372 35 Ronneby
27

SafeTool : Implementering av RFID-teknologi i maskiner för byggbranschen

Svensson, Håkan, Carlsson, Carl January 2007 (has links)
Every year more than 6000 thefts, to a value of 1.5 billion SEK, are reported within the Swedish building trade. Plus all the indirect costs of having the construction site standing still. SafeTool is a newly started company that will try to prevent this problem with a modern technology solution. The key to SafeTool’s solution is RFID – Radio Frequency Identification – and the solution looks like this; All tools are stored in a container on the construction site. Every tool is equipped with a RFID-tag that uniquely identifies the tool. With antennas in the container it is possible to detect when a tool is leaving the container and when it comes back. Every worker must wear a RFID-tag so it will be possible to see who was taking the tool out of the container. The container has no external locks on it, but the RFID-tag works as a key. An antenna on the roof of the container identifies the worker and automatically unlocks the door. All the tool and personnel traffic through the door of the container are reported to a central server via GPRS. The server stores all info in a database. The administration of the system will be done through a website. This paper will show how we made this solution work in practice. How we created and programmed the client and server and the protocol that makes them understand each other.
28

Voice over IP over GPRS

Derakhshanno, Homayoun January 2008 (has links)
The Voice over IP (VoIP) technology has become prevalent today due to its lower cost than traditional telephony and its ability to support new value-added services. Additionally, the increasing availability of wireless internet access has led to research studies examining the combination of wireless network access with voice over IP. With the widespread availability of advanced mobile phones and Pocket PCs, the need for VoIP applications on these mobile platforms is tangible. To enable this, we need to evaluate the current wireless access technologies to see if they can support the necessary traffic and implement software to offer these VoIP services to users. In order to easily implement an IP-based service on GSM technology, we should use the GPRS service provided by the GSM operators. In this thesis, we evaluate Voice over IP service over GPRS in terms of feasibility and quality. Following this we ported a locally developed VoIP program to a Pocket PC (with GSM SIM-card support) which runs Microsoft’s Windows Mobile in order to provide suitable software as needed to offer the service from such a portable device. / VoIP tekniken har blivit en rådande teknik numera på grund av dess lägre kostnader och mervärdestjänster som erbjuds jämfört med traditional telefoni. Samtidigt som tendensen mot mer tillgänglig trådlöst internet har underlättat och därmed driver mera studier inom dessa områden. Den allt mer utbredda användningen av avancerade mobiltelefoner och handdatorer numera har lett till ökat behov av att använda VoIP tekniken för dessa mobila utrustningar är alltmer kännbar. För att möjliggöra användadet av VoIP tekniken så behöver vi först och främst utvärdera dagens existerande teknologier för att stödja iden och för det andra måste vi kunna implementera en mjukvara vilket kan erbjuda olika typer av tjänster för slutanvändaren. För att kunna använda en IP-baserad tjänst på GSM teknologin så måste vi använda oss utan GPRS tjänster som tillhandahålls av GSM opratörer. I detta examens arbete kommer vi att utvärdera VoIP tjänster på GPRS när det gäller kvalitet och möjligheter. Därefter kommer vi att Portning en VoIP mjukvara till en handdator (utrustad med GSM sim-kort) vilket har windows Mobile operativsystemet som erbjuder en rad olika tjänster.
29

[en] PLANNING OF UMTS NETWORKS AND INTEROPERABILITY ASPECTS WITH GSM/GPRS/EDGE NETWORKS / [pt] PLANEJAMENTO DE REDES UMTS E ASPECTOS DE INTEROPERABILIDADE COM REDES GSM/GPRS/EDGE

ROBERTO BATISTA VEREZA DE OLIVEIRA 27 November 2007 (has links)
[pt] O presente trabalho tem como meta analisar os aspectos de planejamento de redes celulares UMTS coexistentes com redes GSM, abordando de forma sintetizada os principais pontos de interesse para as operadoras de telefonia celular móvel que eventualmente estejam considerando a possibilidade de coexistência entre esses sistemas. São abordados de forma especial os processos de interoperabilidade entre as redes UMTS e GSM/GPRS/EDGE. / [en] This work has as its purpose to analyze and present on a concise manner the planning aspects for new UMTS networks as well as its interoperability issues concerning GSM legacy layer, serving as reference for the wireless network providers which adopt UMTS over GSM/GPRS/EDGE as their short-term option for deploying existing networks. It will be given special attention to most of interoperability issues which are defined by the standardization bodies (mainly INTER-RAT) and others which are being offered by some of the most representative equipments providers.
30

TSADA - Sistema de telemetria redundante e tolerante a falhas utilizando tecnologia GSM/GPRS e Zigbee / TSADA - Redundant and fault-tolerant telemetry system techologies using GSM/GPRS and Zigbee

Santos, Fernando Beux dos 22 September 2010 (has links)
This work deals with a telemetry system for agricultural mechanization, using GSM / GPRS and ZigBee Radio Frequency. The whole system is a mechanism for collecting and transmitting data at one point moving to a fixed basis, with a system integration and validation. The system gives priority to transmit GSM / GPRS, permitting as an alternative transmission over ZigBee, controlled common mechanism for failure detection, in case of loss of the GSM / GPRS connection the alternative transmission begins, as the system tries to establish a new connection with the priority transmission , thus making the transmission system redundant. The results were satisfactory as the system ensured the transmission of data with fault tolerance and redundantly in remote locations and different reliefs. / O presente trabalho aborda a pesquisa e o desenvolvimento de um sistema de telemetria para a mecanização agrícola e utiliza tecnologia de transmissão de dados sobre telefonia móvel, GSM/GPRS e Rádio Frequência, através do Zigbee. O sistema como um todo consiste em um mecanismo de coleta e transmissão de dados em um ponto móvel para uma base fixa, com uma forma de integração e validação dos dados. O sistema dá prioridade para a transmissão GSM/GPRS e deixa como alternativa a transmissão por ZigBee, controlado por um mecanismo de detecção de falhas que, em caso de perda da conexão do GSM/GPRS, começa a transmissão alternativa, enquanto o sistema tenta restabelecer uma conexão com a transmissão prioritária e torna o sistema de transmissão redundante. Os resultados alcançados foram satisfatórios pois o sistema garantiu a transmissão dos dados com tolerância a falhas e de forma redundante em locais remotos e de relevos diferenciados.

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