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Proposta de transmissão de dados em redes de telefonia celular CDMA2000.; Proposition of data transmission in a CDMA2000 mobile telephony network.

Oliveira, Ediclei Alves de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 15/09/2006 PT
Relevância na Pesquisa
66.93%
Novas demandas por serviços de valor agregado têm surgido constantemente em sistemas de telefonia celular. Somente o tráfego de voz não tem sido mais suficiente para suprir as necessidades dos usuários, que hoje clamam também por serviços de dados que sejam rápidos, eficientes, baratos, com mobilidade e que atendam às mais diversas aplicações, como correio eletrônico, vídeo-conferência ou acesso à Internet. Este trabalho apresenta um método de determinação das taxas mínimas necessárias nos canais de tráfego para atender a essas aplicações. Utilizando-se da tecnologia CDMA2000, será feita uma análise do impacto na interface aérea da alocação dos canais de tráfego determinados. A mesma análise será feita nos casos em que se determinem taxas mínimas e/ou máximas alocadas para cada usuário, comparando-se também tempo necessário para a transmissão dos dados, eficiência na célula (taxa útil / taxa total transmitida), etc. As conclusões deste trabalho podem indicar estratégias para se atender aos usuários de serviços de dados em redes de telefonia móvel sob diferentes aspectos, como melhor relação custo-benefício, nichos específicos (concentrar-se em serviços que demandem maiores ou menores taxas de transmissão...

Antenas planares de micro-ondas multibandas para terminais móveis de sistemas de comunicação sem fio.; Multi-band microwave planar antennas for mobile terminals of wireless communication systems.

Seko, Murilo Hiroaki
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/02/2013 PT
Relevância na Pesquisa
46.71%
Neste trabalho, foram desenvolvidas antenas planares de micro-ondas multibandas para aplicação em terminais móveis de sistemas de comunicação sem fio. Foi realizado um estudo sobre antenas planares de micro-ondas, com ênfase em técnicas de projeto que possibilitam a operação das mesmas em bandas largas e em múltiplas bandas. A partir dos conhecimentos adquiridos com esse estudo, foram propostas configurações de antenas para terminais móveis de sistemas atuais de telefonia móvel, de WLAN e de WPAN, sistemas esses que têm experimentado nos últimos anos uma grande popularização mundial. Por meio de um procedimento de projeto auxiliado por simulação eletromagnética computacional, as configurações propostas de antenas foram analisadas e otimizadas, visando atender às especificações de projeto estabelecidas para operação nos sistemas mencionados. O desempenho que pode ser obtido com essas configurações de antenas depende de diversos parâmetros geométricos das mesmas, resultando em flexibilidade de projeto para obtenção das bandas de operação desejadas. Protótipos das antenas projetadas foram construídos e caracterizados para validar as configurações propostas de antenas e o procedimento de projeto empregado. Foram desenvolvidas quatro antenas para operação em sistemas de telefonia móvel...

Estudo comparativa de linguagens de programacao para manipulacao de video em telefones móveis; A comparative study of programming languages for video manipulation on mobile phones

Miglioranza, Ewerton Felipe
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
POR
Relevância na Pesquisa
56.68%
A expansão do mercado de telefonia móvel impulsiona o surgimento de novos apare- lhos e tecnologias, juntamente com diferentes meios de programá-los. Dentre essas tec- nologias, a troca de informações multimídias está entre as mais promissoras, pois oferece mais capacidade de comunicação ao usuário final. Contudo, devido às inúmeras platafor- mas e linguagens de programação disponíveis, é comum se deparar com o problema de como analisar e escolher a melhor combinação para esse contexto. Logo, este trabalho realiza um estudo comparativo entre as principais plataformas móveis e linguagens de programação disponíveis, considerando características qualitativas referentes ao projeto das linguagens, características quantitativas focadas no desempenho de aplicações para manipulação e transmissão de vídeo em telefones móveis, bem como as ferramentas e os recursos oferecidos.; The expansion of the mobile telephony market drives the development of new devices and technologies, and with it, new ways to program. Among these technologies, the mul- timedia transmission is one of the most promising, because it offers more communication capabilities to the end user. However, due to the many platforms and programming lan- guages available...

Aspectos competitivos da interconexão em telecomunicações: o caso da telefonia móvel no Brasil; Competitive aspects of interconnection in telecommunications: the case of mobile telephony in Brazil

Silva Neto, José Borges da
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Dissertação
POR
Relevância na Pesquisa
46.9%
Dissertação (mestrado)—Universidade de Brasília, Departamento de Economia, 2011.; A telefonia móvel tem sido apresentada como um resultado de grande sucesso do novo modelo de organização das telecomunicações do Brasil instituído no final da década de 1990. De fato, hoje a telefonia móvel é o mais popular serviço de telecomunicação. No entanto, o problema de acesso é um aspecto estrutural que existe em todas as redes de telecomunicações. Diante desse fato, a probabilidade de exercício de práticas anticompetitivas associadas à terminação móvel é alta. A principal evidência disso é a definição de excessivos preços de terminação móvel no regime de Calling Party Pays (CPP). Assim, esse estudo investiga os estímulos anticompetitivos presentes na terminação móvel no Brasil. Como se verifica nos conflitos de definição dos preços de terminação móvel, os sinais de poder de mercado na terminação móvel são incontroversos. De forma mais grave, há sérias suspeitas de estrangulamento de margens. Essa conduta está ancorada na discriminação entre os preços on-net e os preços off-net pelas operadoras móveis, viabilizada pelos elevados preços de terminação móvel. Por meio de um teste de estrangulamento de margens...

Space matters: the relational power of mobile technologies

Odendaal,Nancy
Fonte: Pontifícia Universidade Católica do Paraná Publicador: Pontifícia Universidade Católica do Paraná
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2014 EN
Relevância na Pesquisa
56.9%
The ubiquitous presence of mobile telephony and proliferation of digital networks imply a critical role for these technologies in overcoming the constraints of space in fragmented cities. Academic literature draws from a range of disciplines but fails to address the significance of new technologies for African and South African cities. Debates on technologies and urban spaces reflect a Northern bias and case literature that dwells on the developmental aspects of ICT do not engage with the broader significance with regards to urban change in African cities. This research addresses these gaps by examining the local transformative qualities of mobile telephony in a South African city, Durban. It focuses on the ways in which informal traders active in the city use technology. Actor-network theory was used in the analysis of the field work, uncovering material and human actors, network stabilization processes and agency in determining the transformative potential of this form of digital networking at city and local scales. Findings indicate that appropriation of technology is informed by livelihood strategies. Innovation is enabled when translation extends to appropriation. More in-depth research is needed on how technology is molded and appropriated to suit livelihoods. Throughout the research the spatial dimensions of the relationship between mobile telephony and networks were considered. The network spaces that emerge from actor relations do not correspond with the physical spaces usually considered in policy.

Gestão da satisfação e fidelidade do cliente : um estudo dos fatores que influenciam na satisfação e fidelidade dos clientes corporativos de telefonia celular; Management of customes satisfaction and loyalty: a study of factors influencing the satisfaction and loyalty to corporate customer of mobile service telephony

Baginski Neto, Luiz Carlos
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia de Produção; Estratégia; Qualidade; Gestão Ambiental; Gestão da Produção e Operações Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia de Produção; Estratégia; Qualidade; Gestão Ambiental; Gestão da Produção e Operações
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
56.84%
The competition in the telecommunications industry has grown in Brazil since the privatization, forcing companies that are active in the market to a growing commitment to quality products and services in order to survive. In this context, this work aims to understand the main factors that influence the degree of satisfaction exists in respect of a mobile operator with its corporate customers. The research covered theoretical concepts and analytical models of quality management system and models of indices related to the measurement of customer satisfaction. For the field research was carried out in a practical application of the main approaches based on this thesis by a case study in corporate segment, through a questionnaire applied to 10 consultants and 40 corporate customers of that company. Comparing the results of research with the consultants and corporate clients there is the concern of respondents to the indicators that comprise the constructs of customer satisfaction, commitment calculated, the price index and the handling of complaints, denoting the dissatisfaction of the general assessment for corporate customers with the carrier, against its current expectations. It is concluded that the mobile operator of the telecommunications industry have a big challenge...

Options to Increase Access to Telecommunications Services in Rural and Low-Income Areas

Muente-Kunigami, Arturo; Navas-Sabater, Juan
Fonte: World Bank Publicador: World Bank
Relevância na Pesquisa
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Recent evidence suggests that increasing overall service coverage and promoting access to telecommunications services have a high economic benefit. Overall, it is estimated that a ten percent increase in mobile telephony penetration could increase economic growth by 0.81 percent in developing countries, whereas a ten percent increase in broadband penetration could increase economic growth by 1.4 percent. In rural and low-income areas in particular, not only do basic telephony services and broadband access allow population to connect with relatives and friends, but they have also introduced a dramatic increase in productivity and in many cases have become the only way for small and medium enterprises in rural areas to access national and, in some cases, global markets. Moreover, the impact of access to telecommunications in rural areas on health, education, disaster management, and local governments has allowed better and more rapid responses, improved coordination, and more effective public management. It is therefore worthwhile to take a second look at all possible policy options...

Collecting High Frequency Panel Data in Africa Using Mobile Phone Interviews

Croke, Kevin; Dabalen, Andrew; Demombybes, Gabriel; Giugale, Marcelo; Hoogeveen, Johannes
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
Relevância na Pesquisa
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As mobile phone ownership rates have risen in Africa, there is increased interest in using mobile telephony as a data collection platform. This paper draws on two pilot projects that use mobile phone interviews for data collection in Tanzania and South Sudan. The experience was largely a success. High frequency panel data have been collected on a wide range of topics in a manner that is cost effective, flexible (questions can be changed over time) and rapid. And once households respond to the mobile phone interviews, they tend not to drop out: even after 33 rounds of interviews in the Tanzania survey, respondent fatigue proved not to be an issue. Attrition and non-response have been an issue in the Tanzania survey, but in ways that are related to the way this survey was originally set up and that are fixable. Data and reports from the Tanzania survey are available online and can be downloaded from: www.listeningtodar.org.

Microglial activation as a measure of stress in mouse brains exposed acutely (60 minutes) and long-term (2 years) to mobile telephone radiofrequency fields

Finnie, J.; Cai, Z.; Manavis, J.; Helps, S.; Blumbergs, P.
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
56.71%
Aim: To determine whether acute or long-term exposure of the brain to mobile telephone radiofrequency (RF) fields produces activation of microglia, which normally respond rapidly to any change in their microenvironment. Methods: Using a purpose designed exposure system at 900 MHz, mice were given a single, far-field whole body exposure at a specific absorption rate (SAR) of 4 W/kg for 60min (acute) or on five successive days per week for 104 weeks (long-term). Control mice were sham-exposed or freely mobile in a cage to control for any stress caused by immobilisation in the exposure module. Positive control brains subjected to a stab wound were also included to confirm the ability of microglia to react to any neural stress. Brains were perfusion-fixed with 4% paraformaldehyde and representative regions of the cerebral cortex and hippocampus immunostained for ionised calcium binding adaptor molecule (Iba1), a specific microglial marker. Results: There was no increase in microglial Iba1 expression in brains short or long-term exposed to mobile telephony microwaves compared to control (sham-exposed or freely moving caged mice) brains, while substantial microglial activation occurred in damaged positive control neural tissue. Conclusion: Acute (60minutes) or longer duration (2 years) exposure of murine brains to mobile telephone RF fields did not produce any microglial activation detectable by Iba1 immunostaining.; John W. Finnie‌...

Heat shock protein induction in fetal mouse brain as a measure of stress after whole of gestation exposure to mobile telephony radiofrequency fields

Finnie, J.; Chidlow, G.; Blumbergs, P.; Manavis, J.; Cai, Z.
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
56.68%
Aim: To determine whether whole of gestation exposure of fetal mouse brain to mobile telephone radiofrequency fields produces a stress response detectable by induction of heat shock proteins (HSPs). Methods: Using a purpose-designed exposure system at 900 MHz, pregnant mice were given a single, far-field, whole body exposure at a specific absorption rate of 4 W/kg for 60 min/day from day 1 to day 19 of gestation. Control mice were sham-exposed or freely mobile in a cage to control for any stress caused by restraint in the exposure module. Immediately prior to parturition on day 19, fetal brains were collected, fixed in 4% paraformaldehyde and paraffin-embedded. Three coronal sections encompassing a wide range of anatomical regions were cut from each brain and any stress response detected by immunostaining for HSP25, 32 and 70. Results: There was no induction of HSP32 or 70 in any brains, while HSP25 expression was limited to two brainstem nuclei and occurred consistently in exposed and non-exposed brains. Conclusion: Whole of gestation exposure of fetal mouse brains to mobile phone radiofrequency fields did not produce any stress response using HSPs as an immunohistochemical marker.; John W. Finnie, Glyn Chidlow, Peter C. Blumbergs...

Entry, Costs Reduction, and Competition in the Portuguese Telephony Industry

Gagnepain, Philippe; Pereira, Pedro
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Trabalho em Andamento Formato: application/pdf
Publicado em /03/2006 ENG
Relevância na Pesquisa
56.65%
We study the e¤ect of entry on costs and competition in the Portuguese mobile telephony industry. We construct and estimate a model that includes demand, network, and cost equations. The latter accounts for ine¢ ciency and cost reducing e¤ort. Our results suggest that the entry of a third operator in 1998 lead to signi cant cost reductions, and fostered competition. We also show that failure to account for cost reducing e¤ort leads to biased estimates of competition in the industry. Finally, we also nd that our estimated price-cost margins are similar to hypothetical Nash margins, if rms are patient, and have optimistic beliefs about the industry growth.

Entry, Costs Reduction, and Competition in the Portuguese Mobile Telephony Industry

Gagnepain, Philippe; Pereira, Pedro
Fonte: Elsevier Publicador: Elsevier
Tipo: info:eu-repo/semantics/acceptedVersion; info:eu-repo/semantics/article
Publicado em //2007 ENG
Relevância na Pesquisa
66.74%
We study the effect of entry on costs and competition in the Portuguese mobile telephony industry. We construct and estimate a model that includes demand, network, and cost equations. The latter accounts for inefficiency and cost reducing effort. Our results suggest that the entry of a third operator in 1998 lead to significant cost reductions and fostered competition. We also show that failure to account for cost reducing effort leads to biased estimates of competition in the industry. Finally, we also find that our estimated price–cost margins are similar to hypothetical Nash margins, if firms are patient and have optimistic beliefs about the industry growth.; Ministerio de Educación y Ciencia (SEJ2004-00670)

Municipal ICT Capacity and its Impact on the Climate-Change Affected Urban Poor : The Case of Mozambique

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Economic & Sector Work :: Social Analysis; Economic & Sector Work
ENGLISH; EN_US
Relevância na Pesquisa
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The objective of conducting this case study on Mozambique is to uncover the pattern of municipal Information and Communication Technology (ICT) impact that may exist in other low-capacity countries with analogous political economy structures in relation to leveraging ICT in public sectors. The study concludes by suggesting measures to link the continent's ICT boom in citizen-based mobile telephony and internet usage with the rapid rise of public sector ICT phenomena as a promising means to plug service delivery gaps. In view of these highlights, this report stands to serve as a valuable resource guide to a wide audience of practitioners, including policy wonks, urban specialists; ICT and climate change enthusiasts, as well as social accountability activists. This report consists of five sections. Section one details the impact of climate change on Mozambique's urban poor while also providing an overview of the country's disaster response system. In view of the decentralization of much of Mozambique's ICT and other resources among municipal governments...

2012 Information and Communications for Development : Maximizing Mobile

World Bank
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
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With some 6 billion mobile subscriptions in use worldwide, around three-quarters of the world's inhabitants now have access to a mobile phone. Mobiles are arguably the most ubiquitous modern technology: in some developing countries, more people have access to a mobile phone than to a bank account, electricity, or even clean water. Mobile communications now offer major opportunities to advance human development from providing basic access to education or health information to making cash payments to stimulating citizen involvement in democratic processes. The developing world is 'more mobile' than the developed world. In the developed world, mobile communications have added value to legacy communication systems and have supplemented and expanded existing information flows. However, the developing world is following a different, 'mobile first' development trajectory. Many mobile innovations such as multi-SIM card phones, low-value recharges, and mobile payments have originated in poorer countries and are spreading from there. New mobile applications that are designed locally and rooted in the realities of the developing world will be much better suited to addressing development challenges than applications transplanted from elsewhere. In particular...

Capturing Technology for Development : An Evaluation of World Bank Group Activities in Information and Communication Technologies, Volume 1. The Evaluation

Independent Evaluation Group
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
ENGLISH
Relevância na Pesquisa
46.91%
Technological innovation drives economic progress. Information and communication technologies (ICT) can be leveraged for development, but harnessing this potential depends on an enabling environment for their production, diffusion, and use. Otherwise, technology can widen rather than narrow existing inequalities. Over the past decade developing countries have seen rapid but uneven growth in ICT access and use. The unprecedented spread of mobile technologies, driven by private sector investment and supported by reforms to promote competition, enabled the growth of phone services for the underserved and poor to levels unseen before. But outside mobile telephony, large gaps exist in high-speed Internet access and broadband connectivity and in the diffusion and use of ICT in business, services, and government the areas where ICT can deliver the largest developmental impacts. The World Bank Group's strategy has sought development results in ICT by promoting (i) sector reform, (ii) access to information infrastructure...

Capturing Technology for Development : An Evaluation of World Bank Group Activities in Information and Communication Technologies, Volume 2. Appendixes

Independent Evaluation Group
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
ENGLISH
Relevância na Pesquisa
46.96%
Technological innovation drives economic progress. Information and communication technologies (ICT) can be leveraged for development, but harnessing this potential depends on an enabling environment for their production, diffusion, and use. Otherwise, technology can widen rather than narrow existing inequalities. Over the past decade developing countries have seen rapid but uneven growth in ICT access and use. The unprecedented spread of mobile technologies, driven by private sector investment and supported by reforms to promote competition, enabled the growth of phone services for the underserved and poor to levels unseen before. But outside mobile telephony, large gaps exist in high-speed Internet access and broadband connectivity and in the diffusion and use of ICT in business, services, and government the areas where ICT can deliver the largest developmental impacts. The World Bank Group's strategy has sought development results in ICT by promoting (i) sector reform, (ii) access to information infrastructure...

Mobilidade, comunicação e consumo: expressões da telefonia celular em Angola, Brasil e Portugal; -

Sato, Silvio Koiti
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 24/03/2015 PT
Relevância na Pesquisa
47.07%
Esta pesquisa reflete sobre o ambiente de mobilidade decorrente da popularização das tecnologias móveis, com redes sem fio, no contexto das Novas tecnologias de informação e comunicação (NTICS). O telefone celular, símbolo da mobilidade informacional-virtual na qual estamos inseridos, cria impactos em diferentes práticas sociais, ao trazer a promessa de permanente conexão a outras pessoas e informações, a qualquer momento e em qualquer lugar. As interações entre telefonia celular e mobilidade, consumo e comunicação são o objeto da pesquisa, que tem o objetivo de analisar o processo comunicacional que envolve a produção de sentido por parte das marcas das operadoras de telefonia celular e suas expressões publicitárias, por um lado, e a apropriação dos significados da mobilidade pelo consumidor e presentes visualmente no espaço público, por outro lado. Este processo é cada vez mais dialógico, numa dinâmica negociada entre as instâncias de produção e consumo, configurando um sistema complexo e integrado. Do ponto de vista da comunicação marcária, nosso recorte se concentra na análise das expressividades publicitárias que valorizam os benefícios da mobilidade, a partir de um roteiro analítico que utiliza a semiótica peirceana como fundamento. Em relação ao consumo...

Use of informal mobile telephony in low income households in Colombia

Gamboa Niño, Luis Fernando; Gutierrez Ramírez, Luis Hernando
Fonte: Facultad de Economía Publicador: Facultad de Economía
Tipo: info:eu-repo/semantics/book; info:eu-repo/semantics/acceptedVersion Formato: application/pdf
Publicado em //2008
Relevância na Pesquisa
66.74%
El acceso a la telefonía móvil en Colombia evidencia ciertas particularidades con respecto a otros países. En Colombia surgió una nueva alternativa de comunicación que consistía en la venta de minutos de celular en las calles y en pequeños negocios durante los primeros años de ésta década. En este documento se analizan las principales características de quienes usan esta modalidad de comunicación con base en una encuesta dirigida a usuarios y no usuarios de bajos ingresos. Se usa un modelo probabilístico para explicar las características de las personas que lo usan y se encuentra que las personas que están en la modalidad de contrato prepago y que viven en ciudades pequeñas tienen una mayor probabilidad de usar esta alternativa de comunicación. De otro lado se encuentra que quienes están con el operador dominante tienden a usar este servicio también de una forma más notoria. Estos resultados parecen indicar que los diferenciales de precios entre las llamadas off-net y on-net así como entre prepago y postpago son los que alimentaron el surgimiento de esta actividad; Access to mobile telephony in Colombia exhibits rather interesting features compared to other countries. Colombia witnessed the beginning of a new alternative for communication consisting in the use of informal resale of minutes on the streets and small stores during the first years of this century. In this paper we are interested in analyzing the main factors that determine the utilization of this kind of service. We use a probabilistic model to explain the characteristics of the people that use ‘informal resale’ on the streets and we find that people in the modality of prepayment and people from small cities has a higher probability of using this alternative. It is also found that people in the firm-leader use more often this service. These results seem indicate that price differentials among on-net and off-net and between prepaid and postpaid are the causes of the rise of this economic activity.

Remote unit for mobile-telephony telemetering for distributed ultrasonic transducers

Rodríguez, Miguel A.; Sanz Sánchez, Pedro Tomás; Zaplana, David; Ramos, Antonio; San Emeterio, José Luis
Fonte: Sociedad Española de Acústica Publicador: Sociedad Española de Acústica
Tipo: Comunicación de congreso Formato: 461217 bytes; application/pdf
ENG
Relevância na Pesquisa
56.6%
6 pages, 5 figures.-- PACS nrs.: 43.35, 43.38, 84.40.-- Communication presented at: Forum Acusticum Sevilla 2002 (Sevilla, Spain, 16-20 Sep 2002), comprising: 3rd European Congress on Acoustics; XXXIII Spanish Congress on Acoustics (TecniAcústica 2002); European and Japanese Symposium on Acoustics; 3rd Iberian Congress on Acoustics.-- Special issue of the journal Revista de Acústica, Vol. XXXIII, year 2002.; In some ultrasonic inspections, distributed measurements have to be made at different locations, which are distant from the station where the data collected must be checked and analysed. In this paper, the design of a remote unit for such purpose is described. This unit is intended to make ultrasonic measurements and transmit them to a local unit. The involved ultrasonic and telecommunication stages are explained. This development combines low-cost commercial devices with own-designed technologies. The design parameters and the block diagrams of each subsystem are detailed. Additionally, the configuration of a laboratory prototype, developed in order to test the design viability, is presented. This prototype includes a high voltage spike generator for the transducer driving, a broad-band signal amplifier, a multiplexed signal acquisition / A-D card...

Cell Phones and Cattle: The Impact of Mobile Telephony on Agricultural Productivity in Developing Nations

Houghton, Daniel
Fonte: Universidade Duke Publicador: Universidade Duke
Formato: 413150 bytes; application/pdf
Publicado em //2009 EN_US
Relevância na Pesquisa
46.68%
This paper examines the impact of mobile telephony on productivity in developing nations. Previous studies have suggested that mobile phones have real impacts on economic outcomes in these countries. Using micro-data from Swaziland, Cambodia, and Honduras, this study looks to identify the effects of mobile phone ownership on household productive outcomes in a two-stage regression. The results provide significant evidence that mobile phone ownership does indeed improve productivity at the household level.; Honors thesis, Department of Economics