On the stabilization mechanism of Doogh (Iranian yoghurt drink) by gum tragacanth

Serum separation in Doogh, a favorite acidic dairy drink in the Middle East, is a major problem which happens due to low pH (≤4.00) and aggregation of caseins. Therefore, in the present study the influence of gum tragacanth (GT) and its soluble and insoluble fractions on prevention of serum separation as well as stabilization mechanisms were investigated using rheological, zeta potential and microscopic measurements. According to our findings, the soluble tragacanthin (T) and GT prevented serum separation at concentrations of 0.100 and 0.200%, respectively. Furthermore, the proper rheological model for control was Newtonian whereas for the others it was Power law. Based on viscoelastic experiments, Dooghs containing T and GT exhibited dominant viscose and elastic behaviors, respectively. In addition, the presence of T and GT changed the zeta potential values from positive to negative. It was elucidated that T adsorbs onto casein and induces stabilization via electrostatic and steric repulsions. Moreover, the insoluble bassorin (B) may assist stabilization by increasing the viscosity.     

Critical dwell time of switched linear systems

In this paper, we consider the relation between the switching dwell time and the stabilization of switched linear control systems. First of all, a concept of critical dwell time is given for switched linear systems without control inputs, and the critical dwell time is taken as an arbitrary given positive constant for a switched linear control systems with controllable switching models. Secondly, when a switched linear system has many stabilizable switching models, the problem of stabilization of the overall system is considered. An on-line feedback control is designed such that the overall system is asymptotically stabilizable under switching laws which depend only on those of uncontrollable subsystems of the switching models. Finally, when a switched system is partially controllable (While some switching models are probably unstabilizable), an on-line feedback control and a cyclic switching strategy are designed such that the overall system is asymptotically stabilizable if all switching models of this uncontrollable subsystems are asymptotically stable. In addition, algorithms for designing switching laws and controls are presented.     

Global stabilization of linear periodically time-varying switched systems via matrix inequalities

1 Introduction An important class of hybrid systems is the class of switched systems, which is a family of differential equations together with rules to switch between them. A switched sys- tem can be described by a differential equation the form x˙ = fα(t,x), where {fα(.) : α ∈ N} is a family of functions that is pa- rameterized by some index set N, and α(.) ∈ N, depend- ing on the system state in each time, is a switching sig- nal/strategy. The set N is typically a finite set. Switc…     

A survey on delayed feedback control of chaos

This paper introduces the basic idea and provides the mathematical formulation of the delayed feedback control （DFC） methodology, which has been widely used in chaos control. Stability analysis including the well-known odd number linfitation of the DFC is reviewed. Some new developments in characterizing the limitation of the DFC are presented. Various modified DFC methods, which are developed in order to overcome the odd number limitation, are also described. Finally, some open problems in this research field are discussed.     

Point-to-point and collision avoidance control of the motion of an autonomous bicycle

This work deals with the stabilization and collision avoidance control of a riderless bicycle (see Figure 1). It is assumed here that the bicycle is controlled by a pedalling torque, a directional torque, and by a rotor mounted on the crossbar that generates a tilting torque.Given two points r_A, r_B, and a circular obstacle in the horizontal plane. Also, given a time interval [0, t_f], where 0 < t_f < ∞. It is shown here that by applying a kind of inverse dynamics control, the motion of the bicycle is stabilized while simultaneously controlling its speed and direction in such a manner that the point of contact between the bicycle's rear wheel and the horizontal plane will be able, during [0, t_f], to move from r_A to r_B without hitting the obstacle.     

基于准多项式的二阶时滞系统的稳定性分析

从频域分析一类二阶时滞系统的稳定性。运用时延微分方程领域的两个结论对特征方程转化而来的准多项式进行稳定性分析，给出了使系统稳定的控制器参数范围。     

Stability analysis and stabilization control of multi-variable switched stochastic systems

In this paper, the mean square (MS) stability and exponential mean square (EMS) stability of multi-variable switched stochastic systems are investigated. Based on the concept of the average dwell-time and the ratio of the total time running on all unstable subsystems to the total time running on all stable subsystems, some sufficient conditions are given to ensure the MS stability and EMS stability of the switched stochastic systems involved. Further, for the switched stochastic control systems with all subsystems controllable or stabilizable, EMS stabilization controls and sufficient conditions on EMS stabilization are presented, and the convergent rates of the closed-loop systems are obtained.