A damage detection algorithm based on the proper orthogonal decomposition technique is presented for health monitoring of structures. The proper orthogonal modes are employed as dynamical invariants to filter out the influence of operational/environmental variations on the dynamic response of the structure. Finite element model of a carbon/epoxy composite plate is used to generate vibration dat...

OFDM renders multipath channels with nite memory equivalent to parallel at fading subchannels, over which equalization amounts to simple phase compensation. If the channel status information is known at the transmitter side, optimal power loading across subchannels is possible. Users mobility, time and carrier asynchronism introduce variations in the equivalent channel impulse response setting ...

A large percentage of the railway bridges in the UK rail network and around Europe are of riveted construction exceeding in many cases 100 years of age. The remaining fatigue life of these bridges is difficult to estimate due to the uncertainties regarding the fatigue behaviour of wrought-iron and older steel material, which was used for their construction, as well as the actual loading and the...

We study the effect of the sample thickness in planar crack front propagation in a disordered elastic medium using the random fuse model. We employ different loading conditions and we test their stability with respect to crack growth. We show that the thickness induces characteristic lengths in the stress enhancement factor in front of the crack and in the stress transfer function parallel to t...

A methodology is presented for bounding all higher moments of the local hydrostatic stress field inside random two phase linear thermoelastic media undergoing macroscopic thermomechanical loading. The method also provides a lower bound on the maximum local stress. Explicit formulas for the optimal lower bounds are found that are expressed in terms of the applied macroscopic thermal and mechanic...

A challenge in nanotechnology is that nanoscale structures exhibit a rate-dependent and apparently random (stochastic) load-deflection behavior when repeated experimental measurements are compared. The variability in mechanical response is due to the extreme nonconvexity of the nanostructure’s energy versus structure function. The many minima of this function correspond to equilibrium states, a...

The design of bit interleavers for convolutionally encoded orthogonal frequency-division multiplexing transmission using rate and power loading is analyzed. The study is based on an equivalent channel model consisting of several independent parallel binary input channel (aka. bit levels). Using insights on the non-iterative decoding of bit-interleaved coded modulation and some effects of rate a...