Publications by Karl Aberer | EPFL Graph Search

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Third party apps that work on top of personal cloud services such as Google Drive and Dropbox, require access to the user’s data in order to provide some functionality. Through detailed analysis of a hundred popular Google Drive apps from Google’s Chrome s ...

In this paper we show that the topologies of most logarithmic-style P2P systems like Pastry, Tapestry or P-Grid resemble small-world graphs. Inspired by Kleinberg’s small-world model [6] we extend the model of building “routing-efficient” small-world graphs and propose two new models. We show that the graph, constructed according to our model for uniform key distribution and logarithmic outdegree, will have similar properties as the topologies of structured P2P systems with logarithmic outdegree. Moreover,

Today the problem of semantic interoperability in information search on the Internet is solved mostly by means of centralization, both at a sys-tem and at a logical level. This approach has been successful to a certain extent. Peer-to-peer systems as a new brand of system architectures indicate that the principle of decentralization might offer new solutions to many problems that scale well to very large numbers of users. In this paper we outline how the peer-to-peer system architectures can be applied to t

Diversification is a method of improving user satisfaction by increasing the variety of information shown to user. Due to the lack of a precise definition of information variety, many diversification techniques have been proposed. These techniques, however ...

Demand response (DR) emerges as one of the cheapest and greenest solutions to match supply and demand in the electricity sector. While DR has been focused on large and industrial consumers, pervasive implementation (by including residential consumers) is n ...

The collection of medical data for research purposes is a challenging and long-lasting process. In an effort to accelerate and facilitate this process we propose a new framework for dynamic aggregation of medical data from distributed sources. We use agent ...

Advances in deep neural network (DNN) architectures have enabled new prediction techniques for stock market data. Unlike other multivariate time-series data, stock markets show two unique characteristics: (i) multi-order dynamics, as stock prices are a.ect ...

In sufficiently large heterogeneous overlays message loss and delays are likely to occur. This has a significant impact on overlay routing, especially on longer paths. The existing solutions to this problem rely on message redundancy to mask the loss and d ...

We explore the use of mobile phone-generated sensor feeds to determine the high-level (i.e., at the semantic level), indoor, lifestyle activities of individuals, such as cooking & dining at home and working & having lunch at the work- place. We propose and evaluate a 2-Tier activity extraction framework (called SAMMPLE1) where features of the low-level accelerometer data are first used to identify individual locomotive micro-activities (e.g., sitting or standing), and the micro-activity sequence is subseque

The advent of online social networks created new prediction opportunities for recommender systems: instead of relying on past rating history through the use of collaborative filtering (CF), they can leverage the social relations among users as a predictor ...

Many structured overlay networks rely on a ring invariant as a core network connectivity element. The responsibility ranges of the participating peers and navigability principles (greedy routing) heavily depend on the ring structure. For correctness guaran ...

P2P content distribution networks have become extremely popular on the Internet. Due to their self-organization properties, they suffer from the lack of control to balance the load among peers for contents of different popularity. In this paper, we define and analyze a fully decentralized architecture to support replication of popular media content in a peer-to-peer network. We show that by exploiting local knowledge only, this method achieves a nearoptimal behavior with respect to response time in a scenar

Due to the limited number of available IP addresses most computers on the Internet use dynamic IP addresses which causes problems for applications that have to maintain rout-ing tables, for example, peer-to-peer systems. To overcome this we propose unique peer identifiers in the routing tables and apply the peer-to-peer system itself to maintain consis-tent id-to-IP mappings to be used in the routing process. While this may sound like a recursive hen-egg problem we show that it is in fact possible to devise

Ambiguities in company names are omnipresent. This is not accidental, companies deliberately chose ambiguous brand names, as part of their marketing and branding strategy. This procedure leads to new challenges, when it comes to finding information about the company on the Web. This paper is concerned with the task of classifying Twitter messages, whether they are related to a given company: for example, we classify a set of twitter messages containing a keyword apple, whether a message is related to the co

Mobile users not only use on-demand location-based services increasingly (e.g., checking in on online social networks), but also other mobile applications that provide a service based on location traces of users (e.g., fitness tracking, health monitoring, etc.). This type of continuous tracking of user location introduces specific challenges to protection of location-privacy of mobile users. One of the challenges is ensuring the preservation of privacy levels of user location over time. Also, it is essentia

Todays complex online applications often require the interaction of multiple services that potentially belong to different business entities. Interoperability is a core element of such an environment, yet not a straightforward one. In this paper, we argue ...

Peer-to-peer networks have been identified as promising architectural concept for developing search scenarios across digital library collections. Digital libraries typically offer sophisticated search over their local content, however, search methods invol ...

Effectively managing the data generated by community-driven mobile geo-sensor networks is a new and challenging problem. One important step for managing and querying sensor network data is to create abstractions of the data in the form of models. These models can then be stored, retrieved, and queried, as required. There has been significant amount of prior literature on using models for query processing [6, 8, 11, 14, 20]. On the contrary, however, there has been a lack of understanding on developing relia

As the online social networks (OSNs), such as Facebook, witness explosive growth, the privacy challenges gain critical consideration from governmental and law agencies due to concentration of vast amount of personal information within a single administrati ...

A growing amount of data is produced daily resulting in a growing demand for storage solutions. While cloud storage providers offer a virtually infinite storage capacity, data owners seek geographical and provider diversity in data placement, in order to a ...

Karl Aberer

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The Curious Case of the PDF Converter that Likes Mozart: Dissecting and Mitigating the Privacy Risk of Personal Cloud Apps

On SmallWorld Graphs in Non-uniformly Distributed Key Spaces

A Framework for Semantic Gossiping

An Evaluation of Diversification Techniques

An Economic Analysis of Pervasive, Incentive-Based Demand Response

A Multiagent System for Dynamic Data Aggregation in Medical Research

Efficient Integration of Multi-Order Dynamics and Internal Dynamics in Stock Movement Prediction

Self-organized fault-tolerant routing in peer-to-peer overlays

Semantic Activity Classification Using Locomotive Signatures from Mobile Phones

Comparing the Predictive Capability of Social and Interest Affinity for Recommendations

Fuzzynet: Ringless Routing in a Ring-like Structured Overlay

A Decentralized Architecture for Adaptive Media Dissemination

Handling Identity in Peer-to-Peer Systems

It was easy, when apples and blackberries were only fruits

A Heuristic Algorithm for Mobility-aware Location Obfuscation

Analyzing the Emergence of Semantic Agreement among Rational Agents

A Peer-to-Peer Architecture for Information Retrieval Across Digital Library Collections

ConDense: Managing Data in Community-driven Mobile Geosensor Networks

My3: A highly-available P2P-based online social network

System and Method for Optimizing Data Storage in a Distributed Data Storage Environment