Publications by Karl Aberer | EPFL Graph Search

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Microblogging sites are a unique and dynamic Web 2.0 communication medium. Understanding the information flow in these systems can not only provide better insights into the underlying sociology, but is also crucial for applications such as content ranking, ...

The Open Support Platform for Environmental Research (OSPER) has been launched to take forward key data management components developed under the Swiss Experiment platform project to achieve improved usability and a wider scope. With this project, we aim to connect users to data and their context, an area identified during SwissEx as having the greatest potential impact on the research community. OSPER has a clear focus on providing the technology for data storage, management and exploitation with a special

Sensor networks are increasingly being deployed in the environment for many different purposes. The observations that they produce are made available with heterogeneous schemas, vocabularies and data formats, making it difficult to share and reuse this dat ...

Minimizing communication cost is a fundamental problem in large-scale federated sensor networks. Maintaining model-based views of data streams has been highlighted because it permits efficient data communication by transmitting parameter values of models, ...

Cloud storage services, like Dropbox and Google Drive, have growing ecosystems of 3rd party apps that are designed to work with users’ cloud files. Such apps often request full access to users’ files, including files shared with collaborators. Hence, whene ...

Non-trivial search predicates beyond mere equality are at the current focus of P2P research. Structured queries, as an important type of non-trivial search, have been studied extensively mainly for unstructured P2P systems so far. As unstructured P2P syste ...

The FuturICT project seeks to use the power of big data, analytic models grounded in complexity science, and the collective intelligence they yield for societal benefit. Accordingly, this paper argues that these new tools should not remain the preserve of ...

Computing statistical measures for large databases of time series is a fundamental primitive for querying and mining time-series data [1–6]. This primitive is gaining importance with the increasing number and rapid growth of time series databases. In this paper we introduce a framework for efficient computation of statistical measures by exploit- ing the concept of affine relationships. Affine relationships can be used to infer statistical measures for time series from other related time series instead of d

Distributed Hash Tables (DHTs) provide a scalable mechanism for mapping identifiers to socket addresses. As each peer in the network can initiate lookup requests, a DHT has to process concurrently a potentially very large number of requests. In this paper, ...

One fundamental issue with existing reputation systems, particularly those implemented in open and decentralized environments, is whitewashing attacks by opportunistic participants. If identities are cheap, it is beneficial for a rational provider to simpl ...

Content storage in a distributed collaborative environment uses redundancy for better resilience and thus provides good availability and durability. In a peer-to-peer environment, where peers continuously leave and rejoin the network, various lazy strategi ...

Directory services are a genuine constituent of any distributed architecture which facilitate binding attributes to names and then querying this information, i.e., announcing and discovering resources. In the web services domain this functionality is provided by UDDI or some of its semantic extensions/counterparts for semantic-based resource description and discovery. All of these approaches deal with functional aspects, i.e., interfaces, of web services but do not address non-functional properties such as

Computational reputation-based trust models using statistical learning have been intensively studied for distributed systems where peers behave maliciously. However practical applications of such models in environments with both malicious and rational beha ...

Graph embedding aims at learning a vector-based representation of vertices that incorporates the structure of the graph. This representation then enables inference of graph properties. Existing graph embedding techniques, however, do not scale well to larg ...

A sliding-window k-NN query (k-NN/w query) continuously monitors incoming data stream objects within a sliding window to identify k closest objects to a query. It enables effective filtering of data objects streaming in at high rates from potentially distr ...

The management of trust and quality in decentralized systems has been recognized as a key research area over recent years. In this paper, we propose a probabilistic computational approach to enable a peer in the system to model and estimate the quality and behaviors of the others subjectively according to its own preferences. Our solution is based on the use of graphical models to represent the dependencies among different QoS parameters of a service provided by a peer, the associated contextual factors, th

There have been many proposals for constructing routing tables for Distributed Hash Tables (DHT). They can be classified into two groups: A) those that assume that the peers are uniformly randomly distributed in the identifier space, and B) those that allo ...

Schema and ontology matching is a process of establishing correspondences between schema attributes and ontology concepts, for the purpose of data integration. Various commercial and academic tools have been developed to support this task. These tools prov ...

This paper describes a novel approach for obtaining semantic interoperability among data sources in a bottom-up, semi-automatic manner without relying on pre-existing, global semantic models. We assume that large amounts of data exist that have been organized and annotated according to local schemas. Seeing semantics as a form of agreement, our approach enables the participating data sources to incrementally de-velop global agreement in an evolutionary and completely decentralized process that solely relies

Effective information retrieval (IR) relies on the ability to comprehensively capture a user's information needs. Traditional IR systems are limited to homogeneous queries that define the information to retrieve by a single modality. Support for heterogene ...

Karl Aberer

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Outtweeting the Twitterers - Predicting Information Cascades in Microblogs

Open Support Platform for Environmental Research (OSPER)-tools for the discovery and exploitation of environmental data

Enabling Query Technologies for the Semantic Sensor Web

Efficiently Maintaining Distributed Model-Based Views on Real-Time Data Streams

"If You Can't Beat Them, Join Them'': A Usability Approach to Interdependent Privacy in Cloud Apps

Efficient processing of XPath queries with structured overlay networks

Towards a global participatory platform Democratising open data, complexity science and collective intelligence

AFFINITY: Efficiently Querying Statistical Measures on Time-Series Data

Congestion Control for Distributed Hash Tables

Using Identity Premium for Honesty Enforcement and Whitewashing Prevention

Internet-scale storage systems under churn - A study of the steady state using Markov models

A Search Engine for QoS-enabled Discovery of Semantic Web Services

Effective Usage of Computational Trust Models in Rational Environments

Scalable Robust Graph Embedding with Spark

Distributed processing of continuous sliding-window k-NN queries for data stream filtering

Probabilistic Estimation of Peers’ Quality and Behaviors for Subjective Trust Evaluation

On Routing in Distributed Hash Tables

Minimizing Human Effort in Reconciling Match Networks

Start making sense: The Chatty Web approach for global semantic agreements

Graph Embeddings for One-pass Processing of Heterogeneous Queries