Examinando por Autor "Gonzalez-Pardo, Antonio"

Mostrando 1 - 5 de 5

A fast variable neighborhood search approach for multi-objective community detection
(Applied Soft Computing (Elsevier), 2021-11) Perez-Pelo, Sergio; Sanchez-Oro, Jesús; Gonzalez-Pardo, Antonio; Duarte, Abraham
Community detection in social networks is becoming one of the key tasks in social network analysis, since it helps analyzing groups of users with similar interests. This task is also useful in different areas, such as biology (interactions of genes and proteins), psychology (diagnostic criteria), or criminology (fraud detection). This paper presents a metaheuristic approach based on Variable Neighborhood Search (VNS) which leverages the combination of quality and diversity of a constructive procedure inspired in Greedy Randomized Adaptative Search Procedure (GRASP) for detecting communities in social networks. In this work, the community detection problem is modeled as a bi-objective optimization problem, where the two objective functions to be optimized are the Negative Ratio Association (NRA) and Ratio Cut (RC), two objectives that have already been proven to be in conflict. To evaluate the quality of the obtained solutions, we use the Normalized Mutual Information (NMI) metric for the instances under evaluation whose optimal solution is known, and modularity for those in which the optimal solution is unknown. Furthermore, we use metrics widely used in multiobjective optimization community to evaluate solutions, such as coverage, ϵ-indicator, hypervolume, and inverted generational distance. The obtained results outperform the state-of-the-art method for community detection over a set of real-life instances in both, quality and computing time.
Automatic procedure following evaluation using Petri net-based workflows
(IEEE Transactions on Industrial Informatics (IEEE), 2017-12-04) Rodriguez-Fernandez, Victor; Gonzalez-Pardo, Antonio; Camacho, David
An operating procedure (OP), also known as checklist or action plan, is a list of actions or criteria arranged in a systematic way, commonly used in areas such as aviation or healthcare to ensure the success of critical tasks and to help decrease human errors. In these areas, operators are hardly trained to follow the OP carefully, but the evaluation of how they are following, it is usually performed manually by an expert instructor. Automating this evaluation process would lead to an objective and scalable analysis of the operator performance, which is extremely important in areas where the number of operators to evaluate is high. This problem, which can be referred as automatic procedure following evaluation, needs of new techniques and formalizations due to current conformance checking methods do not fit well with some aspects of a OP. In this paper, OPs are modeled as Petri Net-based workflows, and interact with the data log of the system to allow an automatic evaluation of the progress and time spent following the OP. In order to illustrate the contributions of this paper, a case study is carried out designing and modeling an emergency OP for an unmanned aircraft system, and evaluating the proposed approach with a battery of tests.
Conformance Checking for Time-Series-Aware Processes
(IEEE Transactions on Industrial Informatics (IEEE), 2020-02-28) Rodriguez-Fernandez, Victor; Trzcionkowska, Agnieszka; Gonzalez-Pardo, Antonio; Brzychczy, Edyta; Nalepa, Grzegorz J.; Camacho, David
An operating procedure (OP), also known as checklist or action plan, is a list of actions or criteria arranged in a systematic way, commonly used in areas such as aviation or healthcare to ensure the success of critical tasks and to help decrease human errors. In these areas, operators are hardly trained to follow the OP carefully, but the evaluation of how they are following, it is usually performed manually by an expert instructor. Automating this evaluation process would lead to an objective and scalable analysis of the operator performance, which is extremely important in areas where the number of operators to evaluate is high. This problem, which can be referred as automatic procedure following evaluation, needs of new techniques and formalizations due to current conformance checking methods do not fit well with some aspects of a OP. In this paper, OPs are modeled as Petri Net-based workflows, and interact with the data log of the system to allow an automatic evaluation of the progress and time spent following the OP. In order to illustrate the contributions of this paper, a case study is carried out designing and modeling an emergency OP for an unmanned aircraft system, and evaluating the proposed approach with a battery of tests.
Statistical analysis of risk assessment factors and metrics to evaluate radicalisation in Twitter
(Future Generation Computer Systems (Elsevier), 2019-04) Lara-Cabrera, Raúl; Gonzalez-Pardo, Antonio; Camacho, David
Nowadays, Social Networks have become an essential communication tools producing a large amount of information about their users and their interactions, which can be analysed with Data Mining methods. In the last years, Social Networks are being used to radicalise people. In this paper, we study the performance of a set of indicators and their respective metrics, devoted to assess the risk of radicalisation of a precise individual on three different datasets. Keyword-based metrics, even though depending on the written language, performs well when measuring frustration, perception of discrimination as well as declaration of negative and positive ideas about Western society and Jihadism, respectively. However, metrics based on frequent habits such as writing ellipses are not well enough to characterise a user in risk of radicalisation. The paper presents a detailed description of both, the set of indicators used to assess the radicalisation in Social Networks and the set of datasets used to evaluate them. Finally, an experimental study over these datasets are carried out to evaluate the performance of the metrics considered.
The four dimensions of social network analysis: An overview of research methods, applications, and software tools
(Information Fusion (Elsevier), 2020-11) Camacho, David; Panizo-Lledot, Angel; Bello-Orgaz, Gema; Gonzalez-Pardo, Antonio; Cambria, Erik
Social network based applications have experienced exponential growth in recent years. One of the reasons for this rise is that this application domain offers a particularly fertile place to test and develop the most advanced computational techniques to extract valuable information from the Web. The main contribution of this work is three-fold: (1) we provide an up-to-date literature review of the state of the art on social network analysis (SNA); (2) we propose a set of new metrics based on four essential features (or dimensions) in SNA; (3) finally, we provide a quantitative analysis of a set of popular SNA tools and frameworks. We have also performed a scientometric study to detect the most active research areas and application domains in this area. This work proposes the definition of four different dimensions, namely Pattern & Knowledge discovery, Information Fusion & Integration, Scalability, and Visualization, which are used to define a set of new metrics (termed degrees ) in order to evaluate the different software tools and frameworks of SNA (a set of 20 SNA-software tools are analyzed and ranked following previous metrics). These dimensions, together with the defined degrees, allow evaluating and measure the maturity of social network technologies, looking for both a quantitative assessment of them, as to shed light to the challenges and future trends in this active area.