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Giuseppe Grassi Author Vitae 《Journal of The Franklin Institute》2010,347(2):438-451
Projective synchronization is a type of chaos synchronization where the response system states are scaled replicas of the drive system states. This paper deals with the propagation of projective synchronization in a series connection of N chaotic discrete-time drive systems and N response systems. By exploiting an observer-based approach, the paper demonstrates that dead-beat projective synchronization (i.e., exact synchronization in finite time for any scaling factor) is achieved between the nth drive and nth response systems. In particular, it is shown that projective synchronization starts from the innermost (Nth) drive-response system pair and propagates toward the outermost (first) drive-response system pair. Only a single scalar synchronizing signal connects the cascaded drive and response systems. Finally, an example illustrates the propagation of different types of chaos synchronization in a series connection consisting of a Gingerbreadman map, a third order hyperchaotic Henon map and a Lozi map. 相似文献
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Victor Wennemar Wiltmann Hans-Christer Holmberg Pasi Pelttari Jussi Mikkola Keijo Häkkinen Olli Ohtonen 《European Journal of Sport Science》2016,16(8):1111-1120
The present study was designed to analyse and compare the kinetics and kinematics associated with three different starting strategies during classic cross-country ski racing. Inside a ski tunnel, 12 elite male skiers performed three sets of three 38?m starts. Each set included one start using: double poling only (DP), diagonal stride only (DIA) and freely chosen (FREE) (i.e. where subjects used the strategy or combination of strategies they felt was fastest) in random order. The first 18?m was performed on a series of force plates that measured horizontal and vertical forces followed by 20?m of a standard snow track. Additionally, cycle characteristics and joint angles were measured. DIA and FREE were faster over 38?m than DP (P?.01). Net horizontal impulse (taking into account both positive and negative impulses) 5–10?m after the start was lower during DP than during DIA and FREE (both P?<?.05). All subjects skied faster when using only DIA for the entire 38?m. Furthermore, the sum duration and frequency of propulsive contacts over the first 18?m was less in DP than DIA and FREE (P?.01). In conclusion, differences between the starting strategies examined was especially pronounced during the initial cycles. Transition from DIA to DP during the start also slowed the skiers, but optimal timing for such a transition was not elucidated. 相似文献
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Victor Pickard 《Critical Studies in Media Communication》2016,33(4):337-351
The field of communication has much to recover from its intellectual history, particularly critical traditions that have been pushed to the margins. Such a project is inherently political: how scholars narrate the histories of their fields reflect tacit assumptions about discursive boundaries and what counts for legitimate scholarship. Prominent historical narratives typically emphasize certain sub-fields and research traditions while giving short shrift to others. Suggesting larger erasures and deeper tensions in the history of the field, this article aims to recover one such neglected thread, embodied by a reformist policy scholar who is all but forgotten in communication research: Charles Siepmann. 相似文献
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