The consensus problem in a multi-agent system with general nonlinear coupling is investigated in this paper. It is demonstrated that, under suitable conditions on communication, all agents approach a prescribed value if a small fraction of them are controlled by simple feedback control. The stability analysis is based on a blend of graph-theoretic and system-theoretic tools where the contractio...

Controlling dynamics of a network from any initial state to a final desired state has many applications in different disciplines from engineering to biology and social sciences. In this work, we optimize the network structure for pinning control. The problem is formulated as four optimization tasks: i) optimizing the locations of driver nodes, ii) optimizing the feedback gains, iii) optimizing ...

Flux pinning mechanism of graphene oxide (GO) doped MgB2 has been systematically studied. In the framework of the collective pinning theory, a B-T phase diagram has been constructed. By adjusting the GO doping level, the pinning mechanism in MgB2 transformed from transition temperature fluctuation induced pinning, δTc pinning, to mean free path fluctuation induced pinning, δl pinning, is observ...

The thickness dependence of the critical current density Jc(d) in films due to the two-dimensional–three-dimensional (2D–3D) pinning crossover at low magnetic fields is addressed, taking into account the spatial correlation of pinning centres, the combined effect of bulk and surface pinning, and the effect of thermal fluctuations. The whole Jc(d) curve for both the 3D and 2D pinning regimes, an...

The pinning phenomena in superconducting Nb films with triangular and honeycomb pinning arrays were explored. Special temperature dependent phenomena were found for both films. For the film with a triangular pinning array, the pronounced matching peaks in the critical currents as a function of magnetic field reduce from six to three within a narrow temperature range. This temperature dependent ...

Periodic pinning arrays can give rise to commensurability effects for the vortex pinning in superconductors. We studied the influence of size and separation of the individual pinning centers made out of magnetic and nonmagnetic dots. While there is some dependence on the dot size, the periodic pinning changes its character drastically, as soon as the separation between dots becomes comparable t...

Synchronization is a ubiquitous phenomenon in nature. Over the last two decades, the synchronization of complex networks receives an increasing attention. This paper aims at developing a new pinning synchronization approach for complex networks by using the heterogeneous information of different nodes cooperatively. Heterogeneous information means the different observation of the reference sign...

We studied the changes in the superconducting properties of Nb films due to an array of Ni dots used as collective pinning sites. To determine the pinning mechanism, thin Ag layers of varying thicknesses were deposited on the Ni dots prior to the Nb film deposition. The Ag deposited on the pinning dots has little effect on the collective pinning phenomena, which implies that the main pinning me...

Magnetic sensing and logic devices based on the motion of magnetic domain walls rely on the precise and deterministic control of the position and the velocity of individual magnetic domain walls in curved nanowires. Varying domain wall velocities have been predicted to result from intrinsic effects such as oscillating domain wall spin structure transformations and extrinsic pinning due to imper...

We studied the effect of disorder on superconducting vortex pinning produced by arrays of artificial pinning sites. The magnetoresistance of samples with pinning configurations varying from a triangular array to an almost random distribution of pinning sites provides a controlled system for such studies. Interestingly even small degrees of order are sufficient to produce enhanced pinning at wel...