Atualmente tem crescido o uso de aparelhos móveis com mais de uma interface de rede para o acesso à Internet, caracterizando em parte as Redes de Próxima Geração (NGN). Outras características da NGN são o acesso sob demanda, no qual o cliente de acesso não seria, necessariamente, usuário de um único provedor e usaria a rede de outros provedores conforme a necessidade, e o gerenciamento de handover (trocas de rede) centrado no usuário, no qual o usuário é quem decide à qual rede vai se conectar e em que momento. Existem algumas implicações relacionadas ao acesso sob demanda que podem melhorar ou piorar a experiência de acesso do usuário e causar certos impactos relacionados à vazão recebida, valor gasto, número de handovers, entre outros. Para o dispositivo móvel gerenciar os handovers, ele precisa obter informações sobre as redes disponíveis como, por exemplo, preço e incentivos, além das informações já obtidas atualmente como força do sinal recebido e identificador do provedor (SSID). Porém, os provedores não possuem um sistema automatizado para fornecer tais informações aos dispositivos móveis. Esta tese apresenta uma avaliação dos impactos das trocas dinâmicas entre provedores Wi-Fi para o usuário móvel...

Os dispositivos de rede sem fio estão cada vez mais populares. Quase todos os dispositivos portáteis atuais possuem uma interface de rede sem fio e pontos de acesso estão acessíveis a baixo custo para uso corporativo e doméstico. No entanto, este aumento no uso de redes sem fio gera novos desafios. O mais crítico deles é com relação à segurança no acesso à rede sem fio. A natureza da comunicação sem fio dificulta a confidencialidade da informação que viaja livremente em forma de ondas eletromagnéticas. Deste modo, as redes sem fio apresentam novas brechas de segurança que não existem em redes cabeadas. Outro desafio em redes sem fio é preservar as conexões da rede de transporte durante o handover. Handover é o processo pelo qual um dispositivo móvel substitui seu ponto de acesso atual por um outro que possui melhor relação sinal-ruído. Durante o handover, as conexões da rede de transporte mantidas pelo dispositivo móvel são comprometidas. Isto ocorre devido aos procedimentos de desassociação e re-associação entre os pontos de acesso e a atualização dos parâmetros de camada três do nó móvel para sua nova localização. Este trabalho tem como objetivo avaliar o impacto da segurança no overhead de handover e propor mecanismos pelos quais as camadas superiores sejam notificadas quando um handover ocorrer.; Wireless devices are becoming more popular. Almost any portable device nowadays has a wireless network interface and wireless access points are available at low cost for commercial or domestic use. However...

Financial Access 2009 introduces the latest data from a survey of financial regulators in 139 countries. It presents indicators of access to savings, credit, and payment services in banks, and in regulated nonbank financial institutions. It is intended for a broad audience of policymakers, researchers, practitioners, multilateral and bilateral investors, in order to guide monetary policy, monitor systemic risks, and collect information on the values of deposits and credit. This report reviews three interventions: disclosure requirements, interest rate caps, and methods to address excessive lending that can result in consumer indebtedness. Improved transparency and disclosure allow borrowers to make informed choices and can facilitate competition in financial markets, eventually leading to lower prices and improved products. Policies to restrict interest rates or credit quantity, especially in consumer credit, seem to have limited effect but require further analysis.

This report highlights key trends, challenges, and opportunities for advancing financial inclusion and presents major high-level policy recommendations for consideration by the Group of 20 (G-20) policy makers to benefit a wider range of developing countries, including many non-G-20 countries. The report serves a broad audience, ranging from policy makers, development finance institutions, and the private sector to experts seeking a synopsis of the key subtopics relevant for financial inclusion and areas of work for advancing progress. The report is organized into four sections. The first recommends broad goals and agenda items to accelerate progress in financial inclusion. The second defines the financial inclusion concept and its importance for economic growth and poverty reduction. The third section provides a snapshot of each of the pillars presented as part of the recommendations, and the fourth section summarizes the way forward. The report also contains an annex that takes a closer look at the microfinance industry as a case in point for reviewing the successes...

Conference Paper; Our objective is to design, analyze, prototype and experimentally study the theoretical underpinnings for a wireless internet that simultaneously achieves deployability, scalability, high performance and a cost-effective economic model. A core building block will be what we call wireless Transit Access Points. A transit access point, or TAP, is a wireless base station with two major features. First, like any standard base station, it provides wireless data services to mobile users. Second, and more importantly, a TAP is capable of high speed wireless links to other TAPs. These connections utilize multiple antennas at each end to dramatically increase the spectral efficiency and throughput of the link. Such TAP-to-TAP links are designed to supplement, or even replace, the wired network infrastructure usually required when deploying wireless data systems. This paper presents the custom hardware platform designed for the TAPs project.

The scope of this thesis is to analyze the feasibility of having different wireless mesh network architectures transfer data to a wired network via a joint (universal) access point (UAP). Additionally this thesis analyzes the feasibility of using similar joint (universal) access point technology to allow heterogeneous wireless mesh network devices in close proximally to the UAP transmit data to/from each other via the UAP. This research also includes evaluating COTS tools for possible implementation of a joint access point as well as seeking partnership with private industry to assist in research efforts and/or the development or joint (universal) access point solution(s). The thesis concludes with a recommendation on application of universal joint point technology, to include recommendations for implementation of such technology in the Tactical Network Topology (TNT) environment.

Applied Science and Technology Studies (COASTS) international field experimentation program at the naval Postgraduate School (NPS) aims to meet this challenge head-on, building a system of systems with technologies available now. A large part of the enabling network for COASTS is an IEEE 802.11 wireless mesh, deployed on the ground, on the sea, and in the air. This thesis tests and evaluates various antenna configurations, using the latest equipment available, building on lessons learned from the COASTS 2005 field experiment. Data is then used to determine the optimum design which allows the greatest range and throughput for the COASTS 2006 topology. Input from NPS advisors, COASTS commercial partners, including Mesh Dynamics, Mercury Data Systems, and the Air Force Force Protection Battlelab, along with extensive testing of available antennas over multiple field experiments, culminates in the successful field testing of the 802.11 network topology. The final configuration provides an impressive and highly reliable aerial and ground based access point range and throughput for the network.

Military environments require flexible network configurations that must adapt under dynamic and mobile operating conditions. Wireless data networks offer some solutions. A wireless network typically requires an access point to bridge network traffic between wireless and wired media. These devices though are often too inflexible for use in such dynamic conditions. One major problem is that they are dedicated to a single type of wired network, usually Ethernet, which prevents them from being used to bridge traffic to other kinds of networks, for example, ATM or even cellular. This thesis shows how any device running a recent Linux kernel can be configured to route packets in way that simulates an access point. The advantages of such a configuration are described and its potential for military use is discussed.

present; anim; This short presentation reviews the following: The differences among 802.11 family of specifications for wireless LAN technology., The impact distance from the Access Point has on the end user's throughput.Animations are used to illustrate the concepts.; IS3502; Computer Networks: Wide Area, Local Area, Global Information Grid

This paper discusses the role of the postal network in expanding access to financial services in Kazakhstan. It reviews the public postal operator within the postal sector and within the broader context of the communications sector. The roles of the postal network and state and privately-owned banks are also reviewed from the perspective of the financial sector development, with particular focus on payments systems development and microfinance. While this country case on Kazakhstan can stand alone, it is an integral part of this large study of the potential of postal networks to coordinate with financial service providers in 7 countries (Egypt, Kazakhstan, Namibia, Romania, Sri Lanka, Uganda, and Vietnam) and 5 regions (Africa, Asia, Eastern Europe and Central Asia, Latin America and the Caribbean, and the Middle East and Northern Africa). Within Central Asia and the other countries of the former Soviet Union, Kazakhstan's postal network is widely regarded as a leader and pioneer in postal innovation, setting an example for other postal operators in the region. An in-depth assessment of Kazakhstan's postal network development options could also be a model to guide other postal networks.

Banking the Poor presents new data collected from two sources: central banks, and leading commercial banks in each surveyed country. It explores associations between countries' banking policies and practices, and their levels of financial access measured in terms of the numbers of bank accounts per thousand adults. It builds on the previous work of measuring financial access through information obtained from regulators, banks, and household surveys. It explores associations between countries' banking policies and practices, and their levels of financial access, measured in terms of the numbers of bank accounts per thousand adults. The extent to which people are banked depends primarily on how wealthy they are. Even in the poorest countries, rich urban customers get access to good banking. Although there are a range of financial services used by the poorest, these are usually provided outside the formal banking system. Banks are used by those above this threshold, usually by salaried employees who have the steady income. Naturally banks are more likely to seek out users with a steady, predicatable income. Expanding credit for enterprises leads to the creation of a salaried class that wants to bank: this is the primary way to increase bank access. While bank clients make up the largest part of those using financial services in most countries...

The group of 20 (G-20) recognizes data and measurement as an essential foundation for advancing financial inclusion at a global level. The data and measurement sub-group, in its first year, was tasked to identify the existing financial inclusion data landscape, to assess the data gaps, to develop key performance indicators, and to lay out the foundations for the framing of financial inclusion target setting approaches. The purpose of this report, prepared for the global partnership for financial inclusion (GPFI), is to highlight the key findings and recommendations of the data and measurement sub-group during its first year, provide input for a roadmap for the GPFI's work plan for the coming year, and to present key policy recommendations for consideration by the G-20 policy makers for the Cannes summit in November 2011. The policy recommendations presented are relevant at the global level, including both G-20 and non-G-20 countries. The GPFI holds the potential for impact on two levels: (i) incorporating guidance on measurement frameworks and prioritizations of targets through GPFI country-level pilots; and (ii) aligning on the roadmap and determining a toolkit for formulating country level targets or goals to help - operationalize GPFI's universal access vision.

In recent years, WLAN technology has been gaining popularity around the world with its sub standard 802.11b receiving major deployments in many indoor and outdoor environments. In this article we investigate the performance of IEEE 802.11b infrastructure networks in the lossless and lossy environments by means of a simulation study. Also, this study shows how the FIFO discipline of the 802.11b MAC affects on the global performance when at least one channel is under the influence of the bursty errors. Furthermore, this paper proposes a channel aware backoff algorithm for the Access Point (AP) to prioritize its transmissions and to accelerate the transmissions in the poor radio channels to enhance the performance of the real time applications. The final results of this simulation study showed that the proposed algorithm is able to enhance the throughput and the delay in lossy environment by an average of 49% and 83% respectively.; Comment: http://www.journalofcomputing.org

This paper examines the impact of system parameters such as access point density and bandwidth partitioning on the performance of randomly deployed, interference-limited, dense wireless networks. While much progress has been achieved in analyzing randomly deployed networks via tools from stochastic geometry, most existing works either assume a very large user density compared to that of access points which does not hold in a dense network, and/or consider only the user signal-to-interference-ratio as the system figure of merit which provides only partial insight on user rate, as the effect of multiple access is ignored. In this paper, the user rate distribution is obtained analytically, taking into account the effects of multiple access as well as the SIR outage. It is shown that user rate outage probability is dependent on the number of bandwidth partitions (subchannels) and the way they are utilized by the multiple access scheme. The optimal number of partitions is lower bounded for the case of large access point density. In addition, an upper bound of the minimum access point density required to provide an asymptotically small rate outage probability is provided in closed form.; Comment: To appear in IEEE Transactions on Communications

WiFi offloading is regarded as one of the most promising techniques to deal with the explosive data increase in cellular networks due to its high data transmission rate and low requirement on devices. In this paper, we investigate the mobile data offloading problem through a third-party WiFi access point (AP) for a cellular mobile system. From the cellular operator's perspective, by assuming a usage-based charging model, we formulate the problem as a utility maximization problem. In particular, we consider three scenarios: (i) successive interference cancellation (SIC) available at both the base station (BS) and the AP; (ii) SIC available at neither the BS nor the AP; (iii) SIC available at only the BS. For (i), we show that the utility maximization problem can be solved by considering its relaxation problem, and we prove that our proposed data offloading scheme is near-optimal when the number of users is large. For (ii), we prove that with high probability the optimal solution is One-One-Association, i.e., one user connects to the BS and one user connects to the AP. For (iii), we show that with high probability there is at most one user connecting to the AP, and all the other users connect to the BS. By comparing these three scenarios...

Inspired by recent industrial efforts toward high altitude flying wireless access points powered by renewable energy, an online resource allocation problem for a mobile access point (AP) travelling at high altitude is formulated. The AP allocates its resources (available energy) to maximize the total utility (reward) provided to a sequentially observed set of users demanding service. The problem is formulated as a 0/1 dynamic knapsack problem with incremental capacity over a finite time horizon, the solution of which is quite open in the literature. We address the problem through deterministic and stochastic formulations. For the deterministic problem, several online approximations are proposed based on an instantaneous threshold that can adapt to short-time-scale dynamics. For the stochastic model, after showing the optimality of a threshold based solution on a dynamic programming (DP) formulation, an approximate threshold based policy is obtained. The performances of proposed policies are compared with that of the optimal solution obtained through DP.; Comment: This paper is an extended version of the paper "Optimizing the service policy of a wireless access point on the move with renewable energy" in Proceedings of 52nd Annual Allerton Conference on Communication...

In this paper, we study the connectivity in one-dimensional ad hoc wireless networks with an fixed access point. In recent years, various closed expressions for the probability of connectivity on one-dimensional networks (interval graphs) have been derived by many researchers. We will provide some numerical validation for them by means of extensive simulations.; Comment: 6 figures

Offers to Dedicate (OTDs) are required by the Coastal Commission as a condition of receiving a coastal development permit. These are only offers and the interest remains with the landowner until the OTDs are accepted by any government agency or a nonprofit agency. The purpose of the OTDs is to mitigate the impact of the proposed project on the public’s ability to access the coast. Since most of these easements were generated between 1980 and 1986 and court cases in 1987-89 challenged the relationship between the “exaction” and the development and have made it almost impossible for the Commission to require any more of these public access easements, the OTDs that the California Coastal Commission has now are very crucial. However, not all the OTDs have to be given the same priority in opening them to the public. This study creates a comprehensive GIS database whose need was identified in the Coastal Commission’s Public Access Action Plan. It also formulates a method of ranking the OTDs based on a scoring method that considers three criteria: date of expiration, proximity to an existing access point as well as topography of the location. These result in a feasibility score and subsequently a priority index that ranks the OTDs as highest...

This article brings results of a case study applied with survey, seeking to analyze the aspects of the digital inclusion through the users of Tabuleiro Digital public Internet access point of the College of Education of the Federal University of Bahia - FACED/ UFBA. The main objective study was intended to investigate the type of digital inclusion, promoted by this Project, in accordance with perspective of the literature present. The specific objectives indicate the characteristics of the profile from the users; types of applications used and purpose of the Internet confrontation with levels of education and social. In this way, the information society and digital inclusion are contextualized; also the aspects of the inclusion of the Tabuleiro are demonstrated and discussed. Finally, with the analysis, was evidenced that the type of digital inclusion of the Project is induced (technique).; Traz resultados de um estudo de caso, aplicado com técnicas de survey, visando analisar os aspectos da inclusão digital através dos usuários do telecentro Tabuleiro Digital da Faculdade de Educação da Universidade Federal da Bahia - FACED/UFBA. O principal objetivo destinou-se a investigar o tipo de inclusão digital, promovida por este Projeto...

This study determined the access, worth assessment and use of information by small-scale farmers in Oyo State. The study described socio-economic characteristics of small-scale cassava farmers; ascertained information access point preferences and analyzed information worth assessment. A multi stage sampling was used to select 360 respondents and data were collected through pre-tested and face validated questionnaire with a reliability coefficient of 0.88. The results show that majority of the cassava farmers (76.4%) had low access to information and 85.6% rated cassava innovation packages as of low worth. The most frequently used access point is oral communication (83%), which was also rated highest in motivation ability (77.7%), regularity (96.3%) and relevance of information (83.4%). Radio was rated as the most persistent (68.5%). social participation, farm size and use of hired labour had a statistically significant effect on access to information (p<0.01). Religious participation, average income and social participation also had a statistically significant effect on information worth assessment (p<0.05). The study recommends that local farmers' groups identified as information providers should be recognized and used in complementing conventional extension efforts. This will improve access...