this paper presents new sensitivity-based methods for detection of structural damage using incomplete noisy modal data. these methods are based on the first-order derivative of modal parameters. changes of natural frequency do not usually provide spatial information on the structural damage. they are also not sensitive to the local damage. in this paper, a new sensitivity function is proposed u...

We study eigenfrequencies and propagator expansions for damped wave equations on compact manifolds. Under the assumption of geometric control, the propagator is shown to admit an expansion in terms of finitely many eigenmodes near the real axis, with an error term exponentially decaying in time. In the presence of a nondegenerate elliptic closed geodesic not meeting the support of the damping c...

The informatization practice of countries all over the world has shown that the level of a government's informatization is one main factor that can affect its international competitive power. At present, e-government construction is regarded as one of the most important tasks for the national economy and society upliftment and informatization in Saudi Arabia. Unlike the traditional governments,...

This study is an attempt to generalize different active mode localization strategies. It is demonstrated that similar results can be obtained by either a passive design which exhibits normal mode localization or by an active controller which is obtained by employing some of the recently proposed design methods of active control methods. Different active control methods proposed for achieving mo...

We have studied the elementary excitations in a two component Bose-Einstein condensate. We concentrate on the breathing modes and find the elementary excitations to possess avoided crossings and regions of coalescing oscillations where both components of the condensates oscillate with the same frequency. For large repulsive interactions between the condensates, their oscillational modes tend to...

Aims. With strong evidence of fast and slow magnetoacoustic modes arising in the solar atmosphere there is scope for improved determinations of coronal parameters through coronal seismology. Of particular interest is the ratio P1/2P2 between the period P1 of the fundamental mode and the period P2 of its first harmonic; in an homogeneous medium this ratio is one, but in a more complex configurat...

We present an accurate and efficient method of modeling second-harmonic generation in two-dimensional structures by use of eigenmode expansion. By using the undepleted-pump approximation we uncouple the calculations for the fundamental and second harmonic. Expansion of the field in eigenmodes gives rise to a linear matrix formalism. The method includes reflections and is especially suited for p...

Normal mode analysis (NMA) is a standard technique for studying the dynamics of biological systems. It provides an analytic description of the dynamics in a macromolecular system near a minimum by using a harmonic approximation of the potential. NMA can be applied in the analysis of protein flexibility. It has been shown that over half of the 3800 Yale protein movements can be modelled in a str...