IMDEA Networks Institute Digital Repository
Not a member yet
1915 research outputs found
Sort by
A Demonstration of ALAS-KA: A Learning Analytics Tool for the Khan Academy Platform
Get PDFInstructors and students have problems monitoring the learning pro-cess from low level interactions in on-line courses because it is hard to make sense of raw data. In this paper we present a demonstration of the Add-on of the Learning Analytics Support in the Khan Academy platform (ALAS-KA). Our tool processes the raw data in order to transform it into useful information that can be used by the students and instructors through visualizations. ALAS-KA is an interactive tool that allows teachers and students to select the provided in-formation divided by courses and type of information. The demonstration is il-lustrated with different examples based on real experiments dataTRUEpu
OpenVLC: Software-Defined Visible Light Embedded Networks
Get PDFThough there has been a lot of interest in Visible Light Communication (VLC) in recent years, a reference platform based on commercial off-the-shelf components is still missing. We believe that an open-source platform would lower the barriers of entry to VLC research and help the VLC community gain momentum.
In this paper we take an initial step toward the goal of a VLC reference platform -- OpenVLC, and present our design and implementation. Built around a credit-card-sized embedded Linux platform with an LED front-end, OpenVLC offers a basic physical layer, a set of essential medium access primitives, as well as interaction with Internet protocols. We investigate the performance of OpenVLC and show how it can be used along with standard networking diagnostics tools.TRUEpu
Communication architecture of a next generation RPAS: design, deployment and campaigns
Get PDFPoster of the meeting where Miguel Ángel Díaz presented his work about drones.FALSEpu
A prototyping methodology for SDN-controlled LTE using SDR
Get PDFIn this demo, we present a software and hardware platform for designing services in the next generation of wireless networks, in which SDN and SDR are expected to play a key role. We use a LabVIEW-based PXI platform in which LTE-like SISO OFDM PHY Layer is integrated with an open source protocol stack. Such platform can be easily used within an SDN framework to prototype PHY/MAC cross-layer algorithms as a solution to tame dense deployment of wireless networks. Furthermore, we present the preliminary integration of advanced PHY-MAC cross-layer algorithms for implementing novel schemes for future wireless networks.TRUEpu
Filtering Noisy 802.11 Time-of-Flight Ranging Measurements
Get PDFTime-of-Flight (ToF) echo techniques have been proposed as a way to estimate the range between regular Wi-Fi stations. Recent works either did not address practical questions for deployability, or made evaluations in basic setups, or used advanced 802.11 hardware designs. We build an approach solely deployed using ToF measurements and relying on software access point (AP) upgrades of simple commercial off-the-shelf 802.11 chipsets. Our solution filters noisy measurements collected by WiFi chipsets of six dollars each, it has been tested across different and heterogeneous setups and testbeds, and has the potential to enable ToF ranging in every Wi-Fi chipsets.TRUEpu
Design and implementation of and Android context-aware application based on Floating Content
Get PDFCo-supervisor: Shahzad Ali, Phd Student, Institute IMDEA NetworksCommunication and information are two concepts that cannot be separated. Right now we are in the middle of the the Information Age (also known as the Computer Age, Digital Age, or New Media Age), a period in human history characterized by the shift from traditional industry that the industrial revolution brought through industrialization, to an economy based on the information computerization.
During this Information Age, we saw how the way of exchanging information mutated and evolved towards more flexible, dynamic and infrastructure-less means with a transition spanning from the advent of the personal computer in the late 1970s, to the Internet's reaching a critical mass in the early 1990s, and finally to the smart-phones, with a widespread public application started late 2000s.
We started to feel the urge to be "always connected" and so smart phones were born to fulfil our needs. They brought into the hands of every person the chance to access the Internet, share their experiences and feelings, upload photo and videos, playing online games and so on, whenever they had the chance to.
Content sharing via the Internet became a widespread means for people to foster their relationships irrespective of physical distance and smart phones supplied the perfect mean the exchange information in a mobile environment.
Right now, smarter mobile devices continue to dominate worldwide and Android is at the forefront.
Total smart mobile device shipments worldwide grew by 37.4 percent annually during the first quarter to approximately 308.7 million units, according to the market insight firm.
Overall, Android remains on top as 59.5 percent of all smart mobile devices shipped last quarter were running Google's mobile operating system.
The growth of mobile computing, and the pervasiveness of smart user devices is progressively driving applications towards context-awareness, i.e., towards applications and services that allow users to exploit "any information that can be used to characterize the situation of an entity". But relying on infrastructure based networks for location-aware services may often not be desirable, while they are still essential to overcome distances and connect people around the world.
By exploiting the diffusion and flexibility of the Android OS combined with the globally-adopted Bluetooth technology, I developed a context-aware, infrastructure-less, application focused on content sharing, solely dependent on the mobile devices in the vicinity using principles of opportunistic networking.
The net result is a best effort application for floating content in which: 1) information dissemination is geographically limited; 2) the lifetime and spreading of information depends on interested nodes being available; 3) traffic can only be created and caused locally; and 4) content can only be added, but not deleted.
This thesis is structured as follows:
Chapter 1. Introduction on social media and content sharing.
Chapter 2. Floating content networks, description and applications.
Chapter 3. Bluetooth, characteristic and protocol overview.
Chapter 4. Presenting "Floaty", an Android application for floating content networks.
Chapter 5. Performance evaluation and tests results.
Chapter 6. Future works and conclusions.Dipartimento di Informatica e SistemisticaUniversita degli studi di Napoli Federico II, Italypu
DRONEE: Dual-radio opportunistic networking for energy efficiency
Get PDFReducing the power consumption of smartphones is becoming more and more important as smartphones become an indispensable component of our daily activities. In this work, we propose a novel scheme, so called DRONEE, that dramatically ameliorates energy efficiency for uplink transmissions, while achieving near-optimal throughput and high fairness levels in cellular networks. Our proposal consists in a novel two-tier uplink forwarding scheme in which users cooperate by forming clusters of dual-radio mobiles for hybrid wireless networks. The impact of our proposal is threefold: (i)(i) energy efficiency is boosted by allowing mobiles to relay the cellular traffic through intra-cluster ad hoc communications, which leads to reduction of power-hungry cellular transmissions; (ii)(ii) cellular capacity is augmented by scheduling uplink transmissions from mobiles with the best channel; (iii)(iii) almost perfect fairness is achieved by allowing users to share the cellular resources within their cluster. We corroborate the practical relevance of our proposal by providing a first-order discussion on the implementability of DRONEE using LTE and WiFi Direct.pu
TorrentGuard: Stopping scam and malware distribution in the BitTorrent ecosystem
Get PDFIn this paper we conduct a large scale measurement study in order to analyse the fake content publishing phenomenon in the BitTorrent ecosystem. Our results reveal that fake content represents an important portion (35%) of those files shared in BitTorrent and just a few tens of users are responsible for 90% of this content. Furthermore, more than 99% of the analysed fake files are linked to either malware or scam websites. This creates a serious threat for the BitTorrent ecosystem. To address this issue, we present a new tool named TorrentGuard for the early detection of fake content. Based on our evaluation this tool may prevent end users from downloading more than 35 millions fake files per year. This could help to reduce the number of computer infections and scams suffered by BitTorrent users. TorrentGuard is already available and it can be accessed through both a webpage or a Vuze plugin.pu
LabVIEW based Platform for prototyping dense LTE Networks
Get PDFNext generation wireless networks (5G) have to cope with significant traffic increase due to heterogeneity of different applications such as high quality video and cloud based applications. Such requirements create the need for a revolutionary change in architecture rather than a series of local and incremental technology updates. A dense heterogeneous deployment of small cells such as pico/femto cells in addition to high power macro cells is foreseen as one of the potential solutions to achieve these requirements. Such a deployment requires innovation at all layers of communication protocol stack (PHY, MAC and higher layers). Moreover, all the new algorithms also need validation in a real-time testbed. However, the ever increasing complexity in all layers of current and future generations of cellular wireless systems has made an end-to-end demonstration of the network limited to industrial research labs or large academic institutions. SDR prototyping for showing such algorithms requires a need to overcome several challenges which arise due to the use of different design flows to address different components of the system (i.e. RF, baseband, and protocol stack). In addition, the components may lack a common abstraction layer. This can result in complications and delays during system development and integration. The NI LabVIEW graphical system design software is able to address these challenges by providing a common development environment for all the heterogeneous elements in the NI SDR system (i.e., the GPP, RTOS, FPGA, converters and RF components), with tight hardware/software integration and a good abstraction layer. This integrated design environment is the primary reason we chose NI LabVIEW SDR platform for prototyping and it enabled us to quickly reach an initial working version of our demonstration system and rapidly iterate on that design. In this demo, we show a LabVIEW based PXI platform in which LTE-like SISO OFDM PHY Layer is integrated with an open source NS-3 protocol stack to prototype PHY/MAC cross layer algorithms within EU FP7 CROWD project (http://www.ict-crowd.eu), which proposes Software Defined Networking (SDN) framework as a solution to tame dense deployment of wireless networks.TRUEpu