1,720,972 research outputs found
Model-Based Mission Assurance/ModelBased Reliability, Availability, Maintainability, and Safety (RAMS)
No full textAmong all the disciplinary analyses performed during the development of a new aircraft, reliability and safety play the most important role for the certification and operation of the aircraft. Traditionally, reliability and safety analyses are document-based, i.e., a vast quantity of tables and reports collect all the assumptions, inputs, decisions, and results. However, this approach entails several disadvantages hampering the quality and the effectiveness of the analyses, especially with the introduction of novel technologies that make the aircraft a system with ever-increasing complexity. Therefore, the research community proposes innovative model-based approaches to support the development of a new aircraft. This chapter specifically focuses on the model-based approaches proposed in literature dealing with reliability and safety analyses
Effect of Progressive Integration of On-Board Systems Design Discipline in an MDA Framework for Aircraft Design with Different Level of Systems Electrification
Full text linkThe on-board design discipline is sometimes ignored during the first aircraft design iterations. It might be understandable when a single on-board system architecture is considered, especially when a conventional architecture is selected. However, seeing the trend towards systems electrification, multiple architectures can be defined and each one should be evaluated during the first tradeoff studies. In this way, the systems design discipline should be integrated from the first design iterations. This paper deals with a progressive integration of the discipline to examine the partial or total effect of the systems design inside an MDA workflow. The study is carried out from a systems design perspective, analyzing the effect of electrification on aircraft design, with different MDA workflow arrangements. Starting from a non-iterative systems design, other disciplines such as aircraft performance, engine design, and aircraft synthesis are gradually added, increasing the sensibility of the aircraft design to the different systems architectures. The results show an error of 40% in on-board systems assessment when the discipline is not fully integrated. Finally, using the work-flow which allows for greater integration, interesting differences can be noted when comparing systems with different levels of electrification. A possible mass saving of 2.6% of aircraft MTOM can be reached by properly selecting the systems technologies used
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
A concurrent three-dimensional value-driven methodology coupling aircraft design, manufacturing and supply chain by leveraging MBSE and MDO technologies
No full textThe research activity described in this paper is framed within the European project AGILE 4.0. A concurrent three-dimensional approach coupling aircraft design, manufacturing and supply chain is formulated by leveraging MBSE and MDO technologies developed in the project. Starting from the modelling of stakeholders, needs and requirements, going through the system architecting, the MDO process is set-up and automatically executed. In this research activity, the focus in on the technologies, models and MDO preliminary results achieved following the entire MBSE-MDO framework for the three-dimensional approach applied to a specific aircraft component, that is the horizontal tail plan
Systems Engineering holistic approach for aircraft, manufacturing and supply chain concurrent design
Full text linkOver years, public perception of aviation has evolved, placing greater emphasis on climate change, sustainable solutions and fastest and most affordable connections. This has led in the Flightpath 2050, a comprehensive vision for European aviation aiming at achieving climate neutrality, global leadership and meeting citizen needs.
To realize these goals, a fundamental shift is necessary in the way aeronautical systems are conceived, built and sustained. The key aspect of this fundamental shift is the integration of manufacturing and supply chain decisions from the early design stages. This integrated approach is crucial for overcoming the limitations
of traditional sequential method, which prevented adaptability to market changes and increased costs. Companies like Airbus, Boeing, Toyota, and Honda have faced these challenges. By adopting an integrated approach and leveraging digital transformation, companies can instead enhance innovation, efficiency, and competitiveness throughout the aircraft life cycle. This research activity, framed in
this context, investigate the following research question:Can making more decisions in the early life-cycle stage increases the value of
complex aeronautical systems? Real-world cases have demonstrated how production-related decisions are oftenmade after the aircraft design has been completed and the related challenges faced.To overcome these issues, and in relation to the identified research question, thiswork aims to demonstrate that: The concurrent conceptual design, manufacturing and supply chain leads to
more competitive, affordable and resilient aeronautical systems. The objective is to formalize, implement and apply a holistic systems engineering framework to demonstrate this hypothesis and provide an answer to the research question. In line with this objective, the literature review covers three key research areas: architectural frameworks, methodologies for the concurrent design and optimization evaluation, value model techniques. This in-depth review highlights key gaps in existing research regarding the use of a systems engineering approach to formalize the concurrent design of the three systems and demonstrate how this can enhance the value of aeronautical systems. In addition, literature still lacks of methodologies enabling the concurrent design evaluation and optimization of architectures integrating product and production choices. In this frame, a Systems for System Framework, shortly S4S Framework, is proposed to allow the concurrent conceptual design of the manufacturing, supply chain and aircraft systems. The S4S formalizes the processes of the life-cycle concept stage for the three systems. Based on the ISO 15288, it encompassesthe definition of stakeholders’ needs and requirements, generation of architecture
alternatives and their evaluation to aid decision-making. To execute the processesof the S4S Framework, a model-based approach is used. This approach provides astructured, integrated, and dynamic way of modelling, representing and analyzingcomplex systems throughout their life cycle. Information is captured in centralizeddigital models that are continuously updated improving accuracy and consistency,
enhancing collaboration, scalability and flexibility leading to faster iterations andsolutions innovation. The application of the S4S Framework in two case studiesdemonstrates its use advantages. The most efficient and competitive aeronauticalsystems can be identified in the solutions tradespace, in alignment with designand production requirements and stakeholders´needs. Aeronautical systems are
so designed to increase the cost-effectiveness, by anticipating the evaluation oflater stages. By integrating production performance assessments into the designphase, designers can make informed decisions that enhance manufacturability andsupply chain efficiency. This integrated approach also helps proactively identifying and addressing potential production bottlenecks, reducing costs and increasingthe overall value of the aeronautical systems. All the activities performed in this study are summarized in the conclusions with the main findings and key recommendations for the future
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