1,720,971 research outputs found
Investigation of the influences of tyre-road friction and engine power on motorcycle racing performance by means of the optimal manoeuvre method
No full textThis paper investigates the influences of the tyre-road friction and of the maximum engine power on the performance of a racing motorcycle. For this purpose the optimal manoeuvre method is applied, which essentially simulates an ideal driver and computes the minimum lap time for a given motorcycle and a given track. The absolute performance of a racing motorcycle is strictly related to the braking and acceleration capabilities. Braking is limited by front- or rear-tyre skidding and by a stoppie event, whereas acceleration is limited by rear-tyre skidding and by a wheelie event. Furthermore, the engine power constitutes a limiting factor during propulsive phases. Effectively the weights of these limiting factors change with the tyre-road friction condition and with the engine power availability. As a consequence, the manoeuvrability of a racing motorcycle varies and riders need to adjust their strategies properly in order to achieve the best performances allowed in any condition. For this purpose a simple L-curve manoeuvre is considered in this paper. First, a detailed description is reported, and then brake and acceleration limiting conditions are considered with respect to a reference configuration. Next, a parametric analysis is carried out at variable friction and maximum engine power, and their influences on lap time are examined. Finally, two representative configurations are evidenced, i.e. lower friction and lower power; furthermore, brake and acceleration limiting conditions are derived analytically by means of a simplified motorcycle model. Accordingly, the representative manoeuvres are interpreted, and the influences of the friction and engine power on curve entering and curve exiting using optimal strategies is examined
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
Analysis of racing motorcycle performance with additional considerations regarding the Mozzi axis.
No full textThe aim of this research is to develop techniques for the analysis of data measured in motorcycle races.
This analysis should highlight the most difficult parts of the circuits, the rider’s skill and effort, the
performance of the vehicle and the achievement of limit conditions for the vehicle and the tyres. Several
analysis techniques are presented and applied to manoeuvres carried out by different motorcycles both
on dry and wet tracks. Interesting results are obtained with a method based on the time rate of the
kinetic energy of orientation, and a criterion for identifying the most exacting phases of the manoeuvre
is proposed
Application of the "Optimal Maneuver Method" for enhancingracing motorcycle performance
No full textThe aim of this work is to improve the performance of a racing motorcycle by means of gearbox tuning. The Optimal Maneuver Method, which essentially simulates an ideal driver and computes the minimum Lap Time for a given motorcycle and a given circuit, is applied. A 1000cc SuperBike motorcycle and two very different racetracks, i.e. a fast one and a slow one, are considered. First the agreement between the Optimal Maneuver Method results and the logged telemetry data is proven, in order to fully justify its application. Next the relationship between gearbox ratio, lap performance and circuit characteristics is investigated and potential improvements are highlighted. Finally gearbox tuning is achieved by a Lap Time optimization procedure, and subsequent performance improvements are discussed
Experimental and numerical analysis of the infulence of tyre's properties on the straight running stability of a sport touring motorcycle
No full textThe behaviour of a motorcycle on the road is largely governed by tyre properties. This paper presents
experimental and numerical analyses dealing with the influence of tyre properties on the stability of
weave and wobble in straight running. The final goal is to find optimal sets of tyre properties that
improve the stability of a motorcycle. The investigation is based on road tests carried out on a sporttouring
motorcycle equipped with sensors. Three sets of tyres are tested at different speeds in the
presence of weave and wobble. The analysis of telemetry data highlights significant differences in
the trends of frequency and damping of weave and wobble against speed. The experimental analysis
is integrated by a parametric numerical analysis. Tyre properties are varied according to the design
of experiments method, in order to highlight the single effects on stability of lateral and cornering
coefficient of front and rear tyres
- …
