1,721,223 research outputs found
Estudo comparativo entre o gráfico de controle simultâneo (X-BARRA,S) e os gráficos de Shewhart para média e desvio-padrão
Full text linkControl charts are tools from Statistical Process Control widely used to monitor key quality characteristics of a product or service. For being extremely efficient in monitoring and improving quality, research is needed to investigate different approaches. However, the diversity of control charts and application methodologies makes the selection of the best combination to implement in a process harder. Furthermore, some works shows a few or no comparison between related subjects, making the selection even harder. The simultaneous (X-bar,S) control char is a case where the presented comparison raise doubts about is effectiveness even compared to Shewhart charts for mean (X-bar) and standard deviation (S). Therefore, this study aims to compare Shewhart control charts for mean (X-bar) and standard deviation (S) with the simultaneous (X-bar,S) chart in terms of ease of identifying the process state, performance with the average run length (ARL), and ability to determine when the deviation occurred in the sample series. To do so, the procedures for constructing control charts were presented, data were simulated to calculate the NMA, and a visual evaluation of the information presented in the charts was carried out. As a result, the innovations presented in the simultaneous (X-bar,S) chart shows inferior advantages compared to traditional Shewhart charts.Os gráficos de controle são ferramentas do Controle Estatístico de Processos amplamente utilizados para monitorar as características de qualidade chaves de um produto ou serviço. Por serem extremamente eficientes no monitoramento e resultarem em melhorias expressivas de qualidade, a pesquisa se faz necessária na investigação de diferentes abordagens. Entretanto, a diversidade de gráficos e metodologias de aplicação dificultam a escolha da melhor combinação para implementação em um processo. Além disso, alguns trabalhos apresentam pouca ou nenhuma comparação com outros trabalhos, dificultando o processo de escolha. O gráfico simultâneo (X-barra,S) é um caso em que as comparações apresentadas deixam dúvidas quanto à eficácia em relação até mesmo aos gráficos de Shewhart para média (X-barra) e desvio-padrão (S). Dessa forma, este trabalho visa realizar a comparação entre os gráficos de controle de Shewhart para média (X-barra) e desvio-padrão (S) e o gráfico simultâneo (X-barra,S) quanto a facilidade em identificar o estado do processo, a performance com o número médio de amostras até alarme (NMA) e a capacidade em determinar o momento em que o desvio ocorreu na série amostral. Para isso, foram apresentados os procedimentos de construção dos gráficos de controle, simulados os dados para cálculo do NMA e realizado a avaliação visual das informações presentes nos gráficos. Como resultado, concluiu-se que as inovações apresentadas no gráfico simultâneo (X-barra,S) geram vantagens inferiores aos tradicionais gráficos de Shewhart
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
REINFORCED CURRICULUM LEARNING FOR AUTONOMOUS DRIVING IN CARLA
No full textAutonomous Vehicles promise to transport people in a safer, accessible, and even efficient way. Nowadays, real-world autonomous vehicles are build by large teams from big companies with a tremendous amount of engineering effort. Deep Reinforcement Learning can be used instead, without domain experts, to learn end-to-end driving policies. Here, we combine Curriculum Learning with deep reinforcement learning, in order to learn without any prior domain knowledge, an end-to-end competitive driving policy for the CARLA autonomous driving simulator. To our knowledge, this is the first work which provides consistent results of our driving policy on all the town scenarios provided by CARLA. Moreover, we point out two important issues in reinforcement learning: the former is about learning the value function in a stable way, whereas the latter is related to normalizing the learned advantage function. A proposal of a solution to these problems is provided
Walking in a smart city: Investigating the gait stabilization effect for biometric recognition via wearable sensors
No full textTechnology is expected to enhance life in a Smart City: everything is intelligent, digital, interconnected, and inclusive. In addition, all everyday activities are facilitated. This paper presents a biometric authentication strategy based on gait dynamics. The produced signals are acquired by the common mobile device accelerometers (especially those embedded in smartphones). The user has nothing to do but normally approach a controlled entry: authentication is automatically triggered by ambient elements (beacons). This transparent protocol entails user awareness of the authentication since the user has to install a suitable app, therefore it does not cause any covert privacy violation. In addition, it allows avoiding any explicit, possibly cumbersome authentication procedure. Last but not least, the use of a sensor directly embedded in everyday users’ equipment supports an efficient approach without the need for further hardware
From Fully Supervised to Blind Digital Anastylosis on DAFNE Dataset
No full textAnastylosis is an archaeological term consisting in a reconstruction technique whereby an artefact is restored using the original architectural elements. Experts can sometimes imply months or years to carry out this task counting on their expertise. Software procedures can represent a valid support but several challenges arise when dealing with practical scenarios. This paper starts from the achievements on DAFNE challenge, with a traditional template matching approach which won the third place at the competition, to arrive to discuss the critical issues that make the unsupervised version, the blind digital anastylosis, a hard problem to solve. A preliminary solution supported by experimental results is presented
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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