1,721,003 research outputs found
Facilitating model-based design of cyber-manufacturing systems
Get PDFManufacturing companies need to go digital. Although this sector leads in automation adoption, some companies struggle to explore emerging innovations such as Cyber-Physical Systems, Digital Twins and “servitisation in manufacturing”. The equipment required to deliver production systems typically combines physical and software components, yet digital innovations require investing in new models and tools, and training in model-based design. In this paper, we report on a new collaboration platform fostering the ability to experiment with digital innovations using a sandbox environment, accessible online via the user browser, and with good acceptance in small experiments by members in the manufacturing community
Using Machine Learning to automatically infer an approximation of a physical system
No full textDissertação de mestrado integrado em Engenharia InformáticaThe development of Cyber-physical Systems (CPSs) models is a complex process which requires deep multi-disciplinary knowledge of the intended topic to model. Added to this complexity is the difficulty of combining multiple models, sometimes without access to their source code, and make them communicate in a harmonious and integrated way in order to represent the vicissitudes of the environment where the physical system is inserted into. Functional Mockup Interface is a set of C headers that define a protocol that allows the interoperability of different models, independently of the programming languages and tools that generated them. A model that implements this interface is called Functional Mockup Unit (FMU).
This dissertation explores the usage of Machine Learning to generate automatically a FMU from parsing a dataset containing the inputs and outputs obtained during the observation of a physical system. A Command-line Interface (CLI) tool named AutoFMU is also presented here, and it accepts as parameters a set of CSV tables and the names of the column that correspond to the inputs and outputs, using several supervised learning algorithms to infer the relationships between these variables. Its invocation results in a file containing a valid FMU ready to be used.
In order to assess its feasibility in a real context, the tool AutoFMU was used to generate approximations of a controller of a line follower robot. The generated models were then simulated in the INTO-CPS program and the robot movements under the purview of the new controller were observed. The values generated by the new models were also compared with the datasets of the original physical unit.O desenvolvimento de modelos de sistemas ciber-físicos é um processo complexo que exige profundos conhecimentos multi-disciplinares do tópico que se pretende modelar. A esta complexidade acresce ainda a dificuldade de combinar múltiplos modelos, por vezes sem acesso ao seu código fonte, e fazê-los comunicar de uma forma harmoniosa e integrada de forma a representar as vicissitudes do ambiente onde o sistema físico se insere. A Functional Mockup Interface é um conjunto de cabeçalhos C que define um protocolo comum que permite a interoperabilidade de diferentes modelos, independente das linguagens de programação e ferramentas que os geraram. Um modelo que implementa esta interface é chamado de FMU.
Esta dissertação explora a utilização de Machine Learning para gerar automaticamente um FMU a partir da análise de um conjunto de dados contendo os inputs e outputs obtidos durante a observação de um sistema físico. Apresenta-se também uma ferramenta de linha de comandos de nome AutoFMU que aceita como parâmetros um conjunto de tabelas CSV e os nomes das colunas que correspondem aos inputs e outputs, utilizando diversos algoritmos de aprendizagem supervisionada para deduzir as relações entre estas variáveis. Da sua invocação resulta um ficheiro que contém um FMU válido pronto a ser utilizado.
De forma a avaliar a sua viabilidade num contexto real, a ferramenta AutoFMU foi utilizada para gerar aproximações de um controlador de um robot que segue uma linha desenhada no chão. Os modelos gerados foram depois simulados no programa INTO-CPS tendo-se observado e comparado os movimentos efetuados pelo robot sob a alçada do novo controlador. Os valores gerados pelos novos modelos foram também comparados com os datasets da unidade física original
Collaborative Development of Embedded Systems
Get PDFThis chapter motivates our interest in collaborative modelling for embedded systems design by describing the challenges faced by developers of contemporary embedded systems
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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