Balanced Graph Partitioning with Apache Spark

A significant part of the data produced every day by online services is structured as a graph. Therefore, there is the need for efficient processing and analysis solutions for large scale graphs. Among the others, the balanced graph partitioning is a well known NP-complete problem with a wide range of applications. Several solutions have been proposed so far, however most of the existing state-of-the-art algorithms are not directly applicable in very large-scale distributed scenarios. A recently proposed promising alternative exploits a vertex-center heuristics to solve the balance graph partitioning problem. Their algorithm is massively parallel: there is no central coordination, and each node is processed independently. Unfortunately, we found such algorithm to be not directly exploitable in current BSP-like distributed programming frameworks. In this paper we present the adaptations we applied to the original algorithm while implementing it on Spark, a state-of-the-art distributed framework for data processing

Political use of twitter: The case of metropolitan mayor candidates in 2014 local elections in Turkey

Twitter, as a free and 140-character microblogging service, is used for many purposes, including political and administrative perspectives. While administrative use is mainly motivated by citizens-administrators interaction, including politically elected, political use is highly visible during election times, not necessarily confined to these times. In this study we focus on a 3-month period twitter use by mayoral candidates in Turkey, particularly at metropolitan cities starting from the first of January till end of the March 30, 2014 when local elections were held. Tweets are categorized as of six types (i.e. information and news sharing, location and activity sharing, personal messages, direct interaction with citizens, better public services, support mobilization) derived from literature. We aim to show, at local scales, how and for which purposes twitter is used at local elections other than that of political campaign. Our results reveal that candidates for metropolitan mayors use twitter for mainly location and activity sharing during elections times as expected. What is unexpected for the study results are tweets sent for better public services as the second most tweeted category

A generic and adaptive aggregation service for large-scale decentralized networks

Aggregation functions are used in distributed environments to make system-wide information locally available in the nodes of a network. The computation of different aggregation functions, e.g., SUMMATION, AVERAGE, MAXIMUM etc., in large-scale distributed systems is challenging and crucial for a wide range of applications. This is especially the case when the input values of these functions dynamically change during system runtime. Related approaches of decentralized aggregation are function-dependent, interaction-dependent, assume static values or cannot always tolerate duplicates and continuously changing information.Intelligent SystemsElectrical Engineering, Mathematics and Computer Scienc

A high-throughput drug screen reveals means to differentiate triple-negative breast cancer.

Plasticity delineates cancer subtypes with more or less favourable outcomes. In breast cancer, the subtype triple-negative lacks expression of major differentiation markers, e.g., estrogen receptor α (ERα), and its high cellular plasticity results in greater aggressiveness and poorer prognosis than other subtypes. Whether plasticity itself represents a potential vulnerability of cancer cells is not clear. However, we show here that cancer cell plasticity can be exploited to differentiate triple-negative breast cancer (TNBC). Using a high-throughput imaging-based reporter drug screen with 9 501 compounds, we have identified three polo-like kinase 1 (PLK1) inhibitors as major inducers of ERα protein expression and downstream activity in TNBC cells. PLK1 inhibition upregulates a cell differentiation program characterized by increased DNA damage, mitotic arrest, and ultimately cell death. Furthermore, cells surviving PLK1 inhibition have decreased tumorigenic potential, and targeting PLK1 in already established tumours reduces tumour growth both in cell line- and patient-derived xenograft models. In addition, the upregulation of genes upon PLK1 inhibition correlates with their expression in normal breast tissue and with better overall survival in breast cancer patients. Our results indicate that differentiation therapy based on PLK1 inhibition is a potential alternative strategy to treat TNBC