1,720,992 research outputs found
A Framework for Human-in-the-loop Monitoring of Concept-drift Detection in Event Log Stream
No full textOne of the main challenges of Cognitive Computing (CC) is reacting to evolving environments in near-real time. Therefore, it is expected that CC models provide solutions by examining a summary of past history, rather than using full historical data. This strategy has significant benefits in terms of response time and space complexity but poses new challenges in term of concept-drift detection, where both long term and short terms dynamics should be taken into account. In this paper, we introduce the Concept-Drift in Event Stream Framework (CDESF) that addresses some of these challenges for data streams recording the execution of a Web-based business process. Thanks to CDESF support for feature transformation, we perform density clustering in the transformed feature space of the process event stream, observe track concept-drift over time and identify anomalous cases in the form of outliers. We validate our approach using logs of an e-healthcare process
Analysis of Language Inspired Trace Representation for Anomaly Detection
No full textA great concern for organizations is to detect anomalous process instances within their business processes. For that, conformance checking performs model-aware analysis by comparing process logs to business models for the detection of anomalous process executions. However, in several scenarios, a model is either unavailable or its generation is costly, which requires the employment of alternative methods to allow a confident representation of traces. This work supports the analysis of language inspired process analysis grounded in the word2vec encoding algorithm. We argue that natural language encodings correctly model the behavior of business processes, supporting a proper distinction between common and anomalous behavior. In the experiments, we compared accuracy and time cost among different word2vec setups and classic encoding methods (token-based replay and alignment features), addressing seven different anomaly scenarios. Feature importance values and the impact of different anomalies in seven event logs were also evaluated to bring insights on the trace representation subject. Results show the proposed encoding overcomes representational capability of traditional conformance metrics for the anomaly detection task
A meta-learning approach for recommendation of image segmentation algorithms
No full textExistem vários algoritmos de segmentação de imagens, porém, não existe um algoritmo que seja adequado para todos os tipos de aplicações envolvendo imagens. Recomendar um algoritmo de segmentação ideal é uma tarefa desafiadora que requer conhecimento sobre o problema e sobre os algoritmos. Nos últimos anos, o Meta-Aprendizado, oriundo do Aprendizado de Máquina, emergiu para contribuir na solução do problema de seleção de algoritmos. Neste trabalho, Meta-Aprendizado foi utilizado para recomendar algoritmos de segmentação de imagens, baseando-se em meta-conhecimento. Experimentos foram realizados em quatro meta-bases (bases de dados de Meta-Aprendizado) diferentes que representam problemas reais, recomendando se três diferentes segmentadores (Otsu, K-means e SVM) são adequados ou não adequados para uma dada imagem. Um conjunto de 44 características baseadas em cor, domínio da frequência, histograma, textura, contraste e qualidade de imagem foi extraído das amostras, para realizar a tarefa de recomendação em diferentes cenários de segmentação. Os resultados mostraram que, em geral, os meta-modelos construídos com o algoritmo Random Forest obtiveram alta performance em recomendar o algoritmo de segmentação,se comparados com os meta-modelos construídos por outros oito algoritmos.There are many algorithms for image segmentation, but there is no optimal algorithm for all kind of image applications. To recommend an adequate algorithm for image segmentation is a challenging task that requires knowledge about the problem and the algorithms.Inthepastyears,Meta-Learning has emerged from the Machine Learning research field to help solving the algorithm selection problem. This paper applies Meta-Learning to recommend image segmentation algorithms based on meta-knowledge. We performed experiments in four different meta-databases that represent various real problems, recommending when three different segmentation techniques are adequate or not. A set of 44 features based on color, frequency domain, histogram, texture, contrast and image quality was extracted from images in order to perform the recommending task in different segmentation scenarios. Results show that Random Forest meta-models were able to recommend the segmentation algorithm at the overall scenario with high predictive performance in comparison to other eight algorithms
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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