The presence of autonomous vehicles on the roads presents an opportunity to compensate the unstable behaviour of conventional vehicles. Ideally vehicles should (i) be able to recover their equilibrium speed, and (ii) react so as not to propagate but absorb perturbations. However, stability analysis in the literature is found to mainly deal with infinite and homogeneous platoons of vehicles, ass...

A finite element model of wellbore stability was proposed for a horizontal well, and drill-string friction lateral collision in the process rotary motion were taken into account. An unconfined compression test used validation, normalized yielded zone area (NYZA) employed to analyze stability, influence on simulated. The results indicated that stress-strain curve numerical simulation consists wi...

Abstract The paper presents a methodology for analyzing the stability of formations of interconnected vehicles that are based on leader-follower relations. The methodology exploits input-to-state stability properties of basic leader-follower interconnections and builds on the propagation of these properties throughout the network to establish global stability bounds. This is formalized using th...

NGH (natural gas hydrate) is a sort of green energy with huge reserves. When drilling and exploiting NGH, the complex environment will aggravate vibration drill string, which destroy stability reservoir make it decompose to produce large amount gas. Gas flows into annular fluid, filling gas–liquid two-phase flow variation in characteristic parameters pipe flow. The mixed string more intense. In...

This paper introduces the notion of formation input-to-state stability in order to characterize the internal stability of leader-follower formations, with respect to inputs received by the formation leader. Formation ISS is a weaker form of stability than string stability since it does not require inter-agent communication. It relates group input to internal state of the group through the forma...

We present a study of coordination behavior in complex violin-bowing patterns involving simultaneous bow changes (reversal of bowing direction) and string crossings (changing from one string to another). Twenty-two violinists (8 advanced amateurs, 8 students with violin as major subject, and 6 elite professionals) participated in the experiment. We investigated the influence of a variety of per...

The throughput of vehicles on highways can be greatly increased by forming vehicle platoons with small inter-vehicle spacings. The control law that maintains stable operation of a platoon is dependent on the lead and preceding vehicle’s position, velocity and acceleration profiles. These profiles guarantee string stability of a platoon and are transmitted via wireless communication networks. Th...

Heavy traffic on highways requires the optimization of inter-distances between vehicles in order to reach time performance and to provide safety solution in transport. Variable spacing and constant spacing are the two policies for the longitudinal control of platoon. Variable spacing doesn’t require a lot of data (position, speed...) from other vehicles, and string stability using only on-board...

We study exact string backgrounds representing a constant magnetic field background in heterotic string theory. These backgrounds are obtained by Kaluza-Klein reduction of a special class of plane wave solutions. For small values of the magnetic field they possess localized closed string tachyons analogous to the Nielsen-Olesen instability of a constant magnetic field in SO(3) Yang-Mills theory...