Put three and three together: Triangle-driven community detection

Community detection has arisen as one of the most relevant topics in the field of graph data mining due to its applications in many fields such as biology, social networks, or network traffic analysis. Although the existing metrics used to quantify the quality of a community work well in general, under some circumstances, they fail at correctly capturing such notion. The main reason is that these metrics consider the internal community edges as a set, but ignore how these actually connect the vertices of the community. We propose the Weighted Community Clustering (WCC), which is a new community metric that takes the triangle instead of the edge as the minimal structural motif indicating the presence of a strong relation in a graph. We theoretically analyse WCC in depth and formally prove, by means of a set of properties, that the maximization of WCC guarantees communities with cohesion and structure. In addition, we propose Scalable Community Detection (SCD), a community detection algorithm based on WCC, which is designed to be fast and scalable on SMP machines, showing experimentally that WCC correctly captures the concept of community in social networks using real datasets. Finally, using ground-truth data, we show that SCD provides better quality than the best disjoint community detection algorithms of the state of the art while performing faster.Peer ReviewedPostprint (author's final draft

L'ombra que projecta: recorregut cap a l'arquitectura

És hora d’endinsar-se en la foscor, en el món encisador de les ombres trepidants que ens persegueixen i constitueixen tot el que ens envolta. Deslligar-nos per un instant, de la supremacia de la llum, i resseguir els moviments de les ombres per entendre com defineixen també, les variables de l’arquitectura. El títol d’aquest assaig juga amb la doble codificació de la paraula projectar, crear-se i poder crear. L’ombra projectada ja té intrínseca en la seva formació la condició de creació, en aquest cas de les figures obscures. D’altra manera, la segona significació, es refereix a la mateixa qüestió que emmena aquesta investigació; la capacitat de l’ombra de projectar, de proposar i induir la creativitat. Al llarg d’aquest camí, intentarem comprendre l’ombra com a matèria de projecte, com a raó, tant de la consciència de l’espai, com de l’arquitectura

Distributed Community Detection with the WCC Metric

Community detection has become an extremely active area of research in recent years, with researchers proposing various new metrics and algorithms to address the problem. Recently, the Weighted Community Clustering (WCC) metric was proposed as a novel way to judge the quality of a community partitioning based on the distribution of triangles in the graph, and was demonstrated to yield superior results over other commonly used metrics like modularity. The same authors later presented a parallel algorithm for optimizing WCC on large graphs. In this paper, we propose a new distributed, vertex-centric algorithm for community detection using the WCC metric. Results are presented that demonstrate the algorithm's performance and scalability on up to 32 worker machines and real graphs of up to 1.8 billion vertices. The algorithm scales best with the largest graphs, and to our knowledge, it is the first distributed algorithm for optimizing the WCC metric.Comment: 6 pages, 6 figure

Daphne: an Intelligent Cognitive Assistant for the design

This project is part of a research grant awarded by the United States NSF (National Science Foundation) under the title: Improved Human-Computer Interaction for Design of Complex Systems.This thesis introduces Daphne, an Intelligent Cognitive Assistant (ICA) designed to help engineers architect Earth observing satellite systems. The purpose of this thesis is threefold: 1) develop the interfaces through which the user interacts with the system, 2) develop the basic intelligence of the system and 3) perform a preliminary experiment to evaluate the effectiveness of the system in improving design outcomes. Three different interfaces have been developed which include different modes of interaction, visual interfaces (including virtual reality) as well as a physical embodiment for non-verbal interaction. An artificial intelligence has been developed to help users explore the design space by providing criticism and suggestions about the design the user is currently working on. Finally a preliminary experiment has been performed to measure the effectiveness of the system. Ultimately, the goal of Daphne is to enable mixed-initiative human-computer design of complex systems, in which humans and Intelligent Cognitive Assistants engage in balanced collaborations: not dominated by the human or the computer but rather engaging in a meaningful dialogue. This project is part of a research grant awarded by the United States NSF (National Science Foundation)

Scalable Software Architecture for the Android Beyond the Stratosphere Satellite Network

The Android Beyond the Stratosphere project aims to create a pico-satellite based on an Android Phone that will act as a technology demonstrator of a new generation of very low-cost personal satellites. The final target of this project is to develop the whole system, with especial efforts on the software (since the hardware is already been given, and minor modifications have to be done to enable a smartphone with the extra capabilities of a picosat). The system, will allow Android applications to be uploaded to the satellite while in orbit. These apps, developed by the commThe aim of this project was to design and develop part of the software for the Android Beyond the Stratosphere project, which is being developed at the Technical University of Catalonia UPC BarcelonaTech, aiming to design a nano-satellite system based on an Android phone. This thesis has focused on the design and implementation of the ABS software architecture and the development of a Software Development Kit (SDK) for this platform. This SDK will allow for apps being uploaded to the satellite while in orbit. These apps, develop by the community, will run on the top of the custom software architecture and will have all the necessary interfaces to the smartphone hardware and attached payloads. An Arduino Mega ADK board (open-source hardware) will interface the different payloads with the phone, being a low-cost, highly-configurable, fast-development platform for nano-satellites. The software has been designed for the current platform (one phone) but it has been taken into account modularity and scalability to enable multiple-units architectures such as satellites constellations or fractionated-spacecrafts.El objetivo de este proyecto fue diseñar y desarrollar parte del software para el proyecto Android Beyond the Stratosphere que está siendo desarrollado en la Universidad Politécnica de Cataluña y que aspira a diseñar un nanosatélite basado en un móvil Android. Esta tesis se ha centrado en el diseño y desarrollo de una arquitectura de software y el desarrollo de un Software Development Kit (SDK) para esta plataforma. Este SDK permitirá subir aplicaciones al satélite mientras éste esté en órbita. Estas aplicaciones, desarrolladas por la comunidad, se ejecutarán sobre nuestra arquitectura de software y tendrá todas las conexiones necesarias con el hardware del teléfono y cargas útiles. Un Arduino Mega ADK (hardware de código abierto) conectará las diferentes cargas útiles con el teléfono, siendo una plataforma de bajo coste y altamente configurable. El software ha sido diseñado para la plataforma actual (1 teléfono), pero se ha tenido en cuenta la modularidad y escalabilidad para permitir múltiples unidades tales como constelaciones de satélites o satélites fraccionados.L’objectiu d’aquest projecte era dissenyar i desenvolupar part del software pel projecte Android Beyond the Stratosphere que està sent desenvolupat a la Universitat Politècnica de Catalunya i que aspira a dissenyar un nanosatèl·lit basat en un mòbil Android. Aquesta tesis s’ha centrat en el disseny i desenvolupament d’una arquitectura de software y el desenvolupament d’un Software Development Kit (SDK) per aquesta plataforma. Aquest SDK permetrà pujar aplicacions al satèl·lit mentres aquest estigui en òrbita. Aquestes aplicacions, desenvolupades per la comunitat, s’executaran a sobre de la nostra arquitectura de software i tindrà totes les connexions necessàries amb el hardware del telèfon i càrregues útils. Un Arduino Mega ADK (hardware de codi obert) connectarà les diferents càrregues útils amb el telèfon, essent una plataforma de baix cost i altament configurable. El software s’ha dissenyat per la plataforma actual (1 yrlrgón) però s’ha tingut en compte modularitat i escalabilitat per permetre múltiples unitats tals com constel·lacions de satèl·lits o satèl·lits fraccionats

A simplified model for bottom trawl fishing gears

Computational modeling is a valuable complementary tool to assess behavior of bottom trawl fishing gears. A simplified model of the gear that mainly affects to the net is proposed. The model is constrained to steady towing conditions, flat seabed and gear symmetry. Simulations proportionate a number of relevant outcomes like distribution of tensions at the warp, balance of forces at the otterboards or spread under different haul conditions such as depth or towing speed. In this paper we mainly focuss on the description and implementation of the model. Nevertheless, some preliminar comparison with experimental data is also shown