In this paper, we treat the string stability as a kind of performance of a linear multi-vehicle system with acyclic formation structures. By using a double-graph model, we can describe information flows and formulate the string stability. This paper provides a systematic way to design the local controller and the system control strategy with the performance constrains. We also present the conne...

In this paper we construct a string-like classical solution, the pion-string, in the linear sigma model. We then study the stability of the pion-string, and find that it is unstable in the parameter space allowed experimentally. We also speculate on the existance of an unstable eta-string, associated with spontaneous breakdown of the anomalous UA(1) symmetry in QCD at high temperatures. The imp...

We present adaptive nonlinear schemes for longitudinal control of automated heavy duty vehicles. An important control objective is string stability, which ensures that errors decrease as they propagate downstream through the platoon. It is well known that string stability requires intervehicle communication if a constant spacing policy is adopted. When vehicles operate autonomously, string stab...

The string theory is a fast moving subject, both physics wise and in the respect of mathematics. In order to keep up with the discipline it is important to move with new ideas which are being stressed. Here I wish to give extracts from new papers of ideas which I have recently found interesting. There are six papers which are involved: I ."Strings formulated directly in 4 dimensions " A. N...

This article deals with the stability analysis of a drilling system which is modelled as a coupled ordinary differential equation / string equation. The string is damped at the two boundaries but leading to a stable open-loop system. The aim is to derive a linear matrix inequality ensuring the exponential stability with a guaranteed decay-rate of this interconnected system. A strictly proper dy...

The design, analysis and experimental validation of a Cooperative Adaptive Cruise Control (CACC) system are presented. Focussing on the feasibility of the implementation, vehicle-to-vehicle communication with the directly preceding vehicle only is considered. This communication structure is known as semi-autonomous ACC and enables ad-hoc platooning and dealing with non-CACCeqquipped vehicles in...

Exact and explicit string solutions in de Sitter spacetime are found. (Here, the string equations reduce to a sinh-Gordon model). A new feature without flat spacetime analogy appears: starting with a single world-sheet, several (here two) strings emerge. One string is stable and the other (unstable) grows as the universe grows. Their invariant size and energy either grow as the expansion factor...

Th e main objective of this paper is to highlight the importance of the fi nancial stability of the global fi nancial system particularly aft er the recent global fi nancial crisis of 200809. Th e major causes of diff erent fi nancial crises possess the same pattern of greed among investors, ineffi ciency of government regulators, central banks and other stakeholders. Th ey have miserably faile...

We present a systematic determination of the order ¯ h fermionic energy shift when an electroweak string is perturbed. We show that the combined effect of zero modes, bound states and continuum states is to lower the total fermionic ground state energy of the string when the Higgs instability of the string is excited. The effect of the Dirac sea is thus to destabilise the string. However, this ...

In analogy to the ow of uids, it is expected that the aggregate density and the velocity of vehicles in a section of a freeway adequately describe the tra c ow dynamics. The conservation of mass equation together with the aggregation of the vehicle following dynamics of controlled vehicles describes the evolution of the tra c density and the aggregate speed of a tra c ow. There are two kinds of...