Living on the Edge: The Role of Proactive Caching in 5G Wireless Networks

This article explores one of the key enablers of beyond $4$G wireless networks leveraging small cell network deployments, namely proactive caching. Endowed with predictive capabilities and harnessing recent developments in storage, context-awareness and social networks, peak traffic demands can be substantially reduced by proactively serving predictable user demands, via caching at base stations and users' devices. In order to show the effectiveness of proactive caching, we examine two case studies which exploit the spatial and social structure of the network, where proactive caching plays a crucial role. Firstly, in order to alleviate backhaul congestion, we propose a mechanism whereby files are proactively cached during off-peak demands based on file popularity and correlations among users and files patterns. Secondly, leveraging social networks and device-to-device (D2D) communications, we propose a procedure that exploits the social structure of the network by predicting the set of influential users to (proactively) cache strategic contents and disseminate them to their social ties via D2D communications. Exploiting this proactive caching paradigm, numerical results show that important gains can be obtained for each case study, with backhaul savings and a higher ratio of satisfied users of up to $22\%$ and $26\%$, respectively. Higher gains can be further obtained by increasing the storage capability at the network edge.Comment: accepted for publication in IEEE Communications Magazin

Demographic Data for Development Decisionmaking: Case Studies From Ethiopia and Uganda

Analyzes the lack of demographic and socioeconomic data, limited access to and use of existing data, and insufficient demand for their application in policy making and resource allocation. Makes recommendations for greater access, demand, and use of data

Potential mass surveillance and privacy violations in proximity-based social applications

Proximity-based social applications let users interact with people that are currently close to them, by revealing some information about their preferences and whereabouts. This information is acquired through passive geo-localisation and used to build a sense of serendipitous discovery of people, places and interests. Unfortunately, while this class of applications opens different interactions possibilities for people in urban settings, obtaining access to certain identity information could lead a possible privacy attacker to identify and follow a user in their movements in a specific period of time. The same information shared through the platform could also help an attacker to link the victim's online profiles to physical identities. We analyse a set of popular dating application that shares users relative distances within a certain radius and show how, by using the information shared on these platforms, it is possible to formalise a multilateration attack, able to identify the user actual position. The same attack can also be used to follow a user in all their movements within a certain period of time, therefore identifying their habits and Points of Interest across the city. Furthermore we introduce a social attack which uses common Facebook likes to profile a person and finally identify their real identity

Liquid Journals: Knowledge Dissemination in the Web Era

In this paper we redefine the notion of "scientific journal" to update it to the age of the Web. We explore the historical reasons behind the current journal model, and we show that this model is essentially the same today, even if the Web has made dissemination essentially free. We propose a notion of liquid and personal journals that evolve continuously in time and that are targeted to serve individuals or communities of arbitrarily small or large scales. The liquid journals provide "interesting" content, in the form of "scientific contributions" that are "related" to a certain paper, topic, or area, and that are posted (on their web site, repositories, traditional journals) by "inspiring" researchers. As such, the liquid journal separates the notion of "publishing" (which can be achieved by submitting to traditional peer review journals or just by posting content on the Web) from the appearance of contributions into the journals, which are essentially collections of content. In this paper we introduce the liquid journal model, and demonstrate through some examples its value to individuals and communities. Finally, we describe an architecture and a working prototype that implements the proposed model

Extension and adoption of biofortified crops: Quality protein maize in East Africa

Biofortified crops, bred for improved nutritional quality, can alleviate nutritional deficiencies if they are produced and consumed in sufficient quantities. These varieties can be promoted based on their agronomic performance or based on their nutritional qualities. Quality protein maize (QPM) was the first biofortified crop and has been disseminated in Africa using both approaches. To study their effectiveness, a survey of rural households was conducted in the maize-growing areas of East Africa, comparing communities with access to QPM extension activities to control communities. The results show that a third to one half of the farmers in project communities participated in extension activities in all countries except Kenya. In these communities, familiarity with QPM was high (74-80% of farmers), again except for Kenya (19%), but understanding of their nutritional benefits was much lower (47-55%, with 7% in Kenya). In all countries, farmers evaluated QPM varieties as good or better than conventional varieties (CV) for post-harvest characteristics. For agronomic characteristics, however, QPM varieties scored better than CV in Uganda, about the same in Tanzania, but less in Ethiopia. Adoption patterns differed widely between the countries: in the project areas it varied from 70% in Uganda, 30% in Tanzania to none in Kenya. In the control areas, adoption was only observed in Uganda (45% of farmers). Factors that significantly influenced adoption were farmers’ participation in extension activities, farmers’ agronomic and post-harvest evaluation of QPM vs. CM, and their understanding of the nutritional benefits of QPM. Evaluation for agronomic performance was found to be more important than knowledge of nutritional benefits, thus favoring the first approach. A reliable seed supply was, however, found to be a basic condition for adoption.Teaching/Communication/Extension/Profession,