1,720,958 research outputs found
Reliability and testing strategies in technical design: A case study of optimization and simulation
No full textOur research group integrating knowledge coming from different fields as aeronautical, mechanical and computer science engineering developed a new methodology to design electromechanical systems saving time and money. By means of an accurate analysis of the design techniques usually adopted, we conceived a seven step design strategy and in the paper we present a particular step of this process applied to a case study we solved with this new methodology. In particular the paper presents in detail two different brake caliper models, each having a well-defined purpose. It is illustrated the experimental validation we did in order to get the best optimization of the system. So described models are useful to design the brake caliper and evaluate its effect on the whole brake system in a cheap and fast way, saving money and achieving the target of guaranteeing reliability standard
Development of an electro-hydraulic brake system minimizing cost
No full textThe paper describes the procedure our research group followed to prototype an Electro-Hydraulic Braking system (EHB). The first step consisted in developing a model of the system, by using the softwares AMESim® and Simulink®. Then the Pedal Force Emulator (PFE) was designed in detail and built. A devoted Hardware-In-the-Loop (HIL) bench was used to test the prototype and the same procedure was followed for the hydraulic unit. It is important to underline that the principal target of the activity consisted in trying to adapt the standard components of a traditional braking system to develop a low cost EHB. Also devoted valves to connect the driver foot to the wheel calipers in case of fault were used to create a reliable failsafe system
Hardware-In-the-Loop with active roll control
No full textActive Roll Control (ARC) is getting one of the most interesting technological innovations in the automotive industry during last years. The paper presents the method adopted by our research group to design Active Roll Control systems for automotive applications. Active Roll Control concept is presented in detail, both from the point of view of the targets and the practical realization. The design process consists of a first part involving the simulation of vehicle dynamics and the evaluation of the effects of the active system, without considering in detail the delays due to the actuation system. The second step of the process consists in simulating in detail the actuation system for ARC, by giving origin to a co-simulation between the same vehicle model and the detailed model of the actuation system. According to the results related to simulation, the actuation system is designed. The paper presents the list of the main problems connected with the structural design of ARC. The described process was carried on both for a hydraulic and an electro-mechanical ARC. Thirdly, the prototypes of both the systems are presented. The analysis of the effectiveness of their performance was implemented through devoted Hardware-In-the-Loop (HIL) test benches. They are described in detail, especially from the point of view of the connection between the hardware of the bench and the software simulating vehicle dynamics. The conclusion of the paper presents a comparison between the hydraulic and the electro-mechanical ARC, by putting in evidence the peculiarities of the solutions, which could be governed by similar control algorithms
Innovative unmanned airship: Avionics and power supply development
No full textThe present work describes, divided into two parts, the development process of the on board avionics, at first, and then of the power supply and electric system of a low speed, low altitude advanced unmanned platform, named Elettra Twin Flyers, which should be employed for reconnaissance, monitoring and telecommunication purposes both in military and civil area. This innovative remotely-piloted airship has been designed and patented by Nautilus S.p.A. and equipped with high precision sensors and communication devices by Galileo Avionica and Selex Communication. For technical and commercial reason a lowcost-high-fidelity Flight Simulator has been also implemented and used to develop a new Ground Station Concept. In particular, the paper focuses on the strong design integration, especially required by the unconventional characteristics of the airship, among the flight controls, the electric power generation and distribution, and the avionic systems. To cut down costs and development time, the avionics of the prototype has been conceived by integrating both aerospace qualified and COTS devices. The use of COTS Inertial Measuring Unit based on MEMS technology, that is getting more and more precise and reliable, has also contributed to the reduction of the avionics weight. A particular subject has been the choice of the digital data network architecture in order to come to a necessary balance between flexibility ad modularity, needed for the prototype development, and complexity in software coding. Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved
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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