1,721,078 research outputs found
Developments in the Use of Failure Rate Data and Reliability Prediction Methods for Hardware
No full textAerospace Engineerin
An implementation model for integrated computer aided maintenance management systems: A systems/cybernetic approach for design, modelling and configuration
No full textElectrical Engineering, Mathematics and Computer Scienc
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
Improving industrial maintenance contract relationships
No full textUnavailability of technical systems, such as aircraft, is expensive. Technical systems require maintenance to prevent and to remedy defects that cause unavailability. Users of technical systems usually bear the consequences of the risk of unavailability, in particular the loss of productivity. This is based on the presumption that users are best able to insure the risks, although maintenance organisations may be more capable to mitigate the risks. The risks are seldom allocated to maintenance organisations because users and maintenance organisations tend to have conflicting objectives. This raises the questions if a maintenance organisation can be motivated to pursue the objective of the user. This would be possible if the maintenance organisation is rewarded for the “commercial success of the user of the technical system”. If the maintenance organisation indeed pursues the objective of the user of the technical system, the maintenance organisation can make autonomous decisions about the maintenance activities. And if the maintenance organisation can make decisions, it can make investments in measures to mitigate risks, knowing that it can decide if these measures will be employed. This research shows that it is efficient and effective to transfer the risks of the unavailability of a technical system from the user to the maintenance organisation on the condition that the maintenance organisation (a) will be compensated for the risks of unavailability, (b) will be rewarded for the contribution of the technical system to the commercial success of the user, and (c) is assigned the required decision rights. This will in practice require new “collaborative” contracts that can be used for the supply of long-term maintenance services of technical systems where unavailability causes a significant economic risk, for example in aircraft maintenance.Aerospace Industrial Engineering and ManagementAerospace Engineerin
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
From space exploration to commercialisation
No full textSpace exploration has captured the imagination and dreams of many scientists, engineers and visionaries.The ISS is being built by five ISS partners; NASA, RSA, ESA, CSA and JAXA. ISS commercialisation is the process by which ISS products and services are sold to private companies, without transferring ISS ownership. This thesis has two objectives; to propose a collaboration between space agencies and commercial partners and to describe and predict strategic and market developments in ISS commercialisation. The methodology used in this research is typically case-based and collaboration creation is chosen as a major research subject for this thesis. ISS commercialisation is characterised by a cooperative oligopoly: emerging ISS markets and dependence on Russia for regular ISS access. The expected growth of the space tourism, sponsorship markets and the creation of privately funded transportation vehicles (i.e. SpaceShipOne) are some of the current market developments. Cooperative oligopoly is the expected market structure for the future ISS commercial environment. A joint venture for high market demand for ISS products and services and a licensing agreement for medium market demand are the proposed collaborations. These collaborations can also be applied for ISS partners' Moon and Mars space-exploration, navigation, earth observation and technology transfer programmes. Today's ISS commercialisation can become the basis for tomorrow's partial commercial exploitation on interplanetary space missions.Aerospace Engineerin
Consequences and challenges of GLARE for structural repair and newly designed fuselage structures
No full textAerospace Engineerin
LCC-OPS: Life Cycle Cost Application in Aircraft Operations
No full textObservation of current practices in aircraft operations and maintenance shows limited consideration of cost savings applied by aircraft modifications, maintenance program optimisation and aircraft selection. This is due to hidden (maintenance dependent) costs and difficulties in quantifying the utilisation of a higher availability or reduction of revenue losses. Hidden costs can be a significant portion of operating costs and could be reduced by a better aircraft reliability. Most of the decisions for aircraft modification and maintenance program optimisation are made only to fulfil airworthiness or operational requirements. The considerations for the impact of aircraft reliability and maintenance dependent costs on life cycle cost are limited during aircraft selection, because operational data is very limited and the methods to quantify technical delays and cancellations are not available. This situation can be improved by a better quantification of the required investment and the savings achieved by a proper evaluation of the implemented modifications and maintenance program optimisations. In this thesis a Life Cycle Cost model is developed, called LCC-OPS, which visualises the hidden costs and quantifies opportunity revenues or losses. This model will provide an objective calculation and evaluation of the current and projected alternatives.Aerospace Engineerin
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