​With an optimistic assumption that a WiFi Access Point (AP) is idle for 50% of the time, an approximate energy waste caused exclusively by WiFi APs worldwide is estimated to be a striking 4.7 Billion KWh/year. Furthermore, many other types of future wireless network devices are expected to spend substantial amounts of energy in their idle listening modes, including wireless sensor and actuator nodes, wireless smart meters, mobile phones, and cellular base stations.

At Spotify we try to connect millions of people with their favorite music and build the best music service in the world. We believe that music should be easily accessible and than listening to music improves everybody lives. But achieving this goal is not easy and our team needs to face all kind of problems: from scalability issues to coordinate 200 engineers working together. One of our backend engineers will talk about how Spotify solves these issues from the moment you press Play.

In the era when Facebook and Twitter dominate the market for social media, Google has introduced Google+ (G+) and reported a significant growth in its size while others called it a ghost town. This begs the question that "whether G+ can really attract a significant number of connected and active users despite the dominance of Facebook and Twitter?".

El proyecto MEDIANET (S2009/TIC-1468) organiza una jornada de divulgación de los resultados obtenidos hasta la fecha. En dicha jornada participarán investigadores de los cuatro grupos integrantes del proyecto, quienes presentarán sus trabajos de investigación enmarcados dentro del proyecto. Además, esta jornada servirá también para discutir los retos más importantes que debemos afrontar en Internet, poniendo especial hincapié en los servicios multimedia en la Internet del futuro. El workshop MEDIANET 2013 se celebrará el próximo 19 de Abril en el campus de Leganés de la Universidad Carlos III de Madrid (sala 4.1.S08 de la Biblioteca Rey Pastor). Las charlas serán en inglés para dar una mayor difusión al evento, que será de libre acceso, aunque se requiere registro previo utilizando el siguiente formulario web http://goo.gl/cuAvB Descargar programa del evento  (71 KB)

Complex networks, including the Internet, wireless and cellular networks, and on-line social networks, are becoming indispensable parts of our daily lives. These networks arising from a wide range of applications can be represented and studied as graphs, and the underlying link patterns play an important role in understanding and solving problems in such applications. For example, many online social networks, such as Twitter and Google+, can be viewed as directed graphs with uni-directional "following'' relations among users, and the link directions contain crucial information about how users form social communities. In another application, online social networks such as Slashdot and Epinions represent relationships between users as links with positive or negative weights, which correspond to friend and foe relations. These networks are referred to as signed networks, where those signed links generate new challenges in understanding and studying the underlying network properties. In this talk, I present my work on developing theories for studying and characterizing various crucial graph properties, such as the edge directionality in directed graphs and the edge polarity in signed graphs. I do so by emphasizing on applications to detecting stable social communities and understanding social influence propagation patterns on online social networks.

This unique conference will be the venue fostering dialogue among scholars and practitioners belonging to these disciplines.

802.11 wireless local area networks have been designed for wireless communication. The principle for 802.11 communication is that frames are acknowledged (ACKed) after a short and predefined MAC idle time. Despite the MAC idle time is designed to be constant, we find that it varies with i) the physical distance between stations, caused by the delay of wireless signal propagation, and ii) the time to detect the ACK at the local station, which varies with the signal strength of the incoming ACK. Exploiting this knowledge, we present CAESAR, CArriEr Sense-bAsed Ranging, that combines time-of-flight and signal-to-noise ratio measurements to calculate the distance between two stations. CAESAR measures the distance by estimating the MAC idle time in a data/ACK communication at a 44 MHz clock resolution and the ACK detection time on a per-frame basis. CAESAR is a software-based solution that is entirely implemented at the transmitter and it requires no 802.11 protocol modifications. We implement CAESAR on commodity hardware and conduct extensive experiments both in controlled network conditions and dynamic radio environments.  Our measurements confirm the accuracy of the solution and show the capability to track the distance to WLAN smartphones at pedestrian speeds. The work above has been conducted at Disney Research and published at ACM Conext'11. The last part of the talk will briefly present ongoing research activities conducted at ETHZ in the area of time-of-flight WLAN localization.

Intercell coordination and cooperation techniques are some of the most promising approaches to increase the spectral efficiency of future wireless systems as required by the forecasted market needs. Among them, intercell coordinated scheduling (ICCS) arises as a near-term feasible solution due to its lower inter-BS communication requirements when compared to full cooperative approaches. In this paper we present our proposed Reservation Information Aware Intercell Coordinated Scheduling (RIA-ICCS) solution which considers application reservation information when constructing an interference graph for ICCS purposes.

Logged messages are invaluable for debugging and diagnosing problems. Unfortunately, many execution logs are inscrutable in their raw form. For example, a production Google system may generate a billion-line log file in a single day. In my talk, I will detail two log-analysis tools that I developed to deal with this problem. These tools infer concise and precise models from large execution logs of sequential and distributed systems. Both tools enable new kinds of program analyses and make logs more useful to developers.

Arturo Azcorra presentará cuáles son, en su experiencia personal, las mejores prácticas para la redacción de un documento técnico. La conferencia cubrirá algunas ideas a seguir y algunos problemas a evitar al escribir un artículo.