1,721,266 research outputs found
Automatic Regression Testing of Simulation Models and Concept for Simulation of Connected FMUs in PySimulator
Get PDFThe Modelica and FMI tool ecosystem is growing each year with new tools and methods becoming available. The open Modelica standard promises portability but it is important to ensure that a certain model behaves the same in different Modelica tools or in a different version of the same tool. It is also very important (for model evolution) to check that a new version of the same model produces comparable results. Finally, it is desirable to verify that a model exported in FMU form from a Modelica tool gives exactly the same results as the original model. This paper presents a framework for automatic regression testing as part of PySimulator which provides an efficient and concise way of testing if a model or a range of models behaves in the same way in several tools or versions of a tool by checking that the results produced are essentially identical. The FMI standard has been adopted by many tool vendors and is growing in popularity each year. This paper proposes a concept for building and simulating a system made from connected FMUs generated by different tools. The FMUs for Co-Simulation can be connected together using a GUI. The system model built graphically in this way can be saved for later use or simulated directly inside PySimulator. Active development is going on to support simulation of connected FMUs for Model Exchange
Modeling of a Racing Car with Modelica's Multi-Body Library
No full textThe modular modeling of the 3-dimensional mechanics of a racing car with Modelica is discussed. For example, one base model class of the wheel suspension is defined and used to model 4 occurences in the front and rear suspension. This model of the car is based on a new Modelica library to model 3-dimensional mechanical systems. This library is explained in some detail
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
Package PowerTrain: A Modelica library for modeling and simulation of vehicle power trains
No full textIn this article a new Modelica library to model vehicle power trains is discussed. An overview of the elements within the library is given, such as planetary gearsets, laminar clutches, torque losses, driver, warm up model. The library is demonstrated through the discussion of two illustrative examples, for drive cycle fuel consumption prediction and for investigating gearshift transition dynamics of an automatic gearbox. Together with the Modelica simulation environment Dymola, this library is suited and used for HIL (Hardware-In-the-Loop) simulations
Modeling 3D Mechanical Effects of 1D Powertrains
No full textIt is described how to extend one-dimensionally modelled rotational mechanical systems such that they can be mounted on three-dimensional multi-body system models without neglecting any dynamic effects. This is performed by adding support torques to existing drive train elements and by introducing new components that take care of the gyroscopic torques and the transformation of one-dimensional into threedimensional support torques. It is demonstrated that this approach is convenient for the user and leads to efficient simulation code
Nonlinear Dynamic Inversion Control for Wind Turbine Load Mitigation based onWind Speed Measurement
No full textThe design of an advanced controller for wind turbine
load mitigation is presented. The controller is based on
Nonlinear Dynamic Inversion control methods combined
with Pseudo Control Hedging to account for the actuator
limits and a two degree of freedom control system
for the collective pitch control of the rotor blades. The
controller uses wind speed measurement information to
adjust to wind gust load. A newly developed wind turbine
system dynamics library in the Modelica language
is used to model an elastic wind turbine for a simulation
study of the controller. The simulation results show a
large reduction of the gust load on the wind turbine using
the proposed controller
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
- …
