SUMMARYModel-based non-destructive evaluation proceeds measuring the response after an excitation on an accessible area of the structure. The basis for processing this information has been established in recent years as an iterative scheme that minimizes the discrepancy between this experimental measurement and sequence of measurement trials predicted by a numerical model. The unknown damage that minimizes this discrepancy by means of a cost functional is to be found. The damage location and size is quantified and sought by means of a well-conditioned parametrization. The design of the magnitude to measure, its filtering for reducing noise effects and calibration, as well as the design of the cost functional and parametrization, determines the robustness of the search to combat noise and other uncertainty factors. These are key open issues to improve the sensitivity and identifiability during the information processing. Among them, a filter for the cost functional is proposed in this study for maximal sensitivity to the damage detection of steel plate under the impact loading. This filter is designed by means of a wavelet decomposition together with a selection of the measuring points, and the optimization criterion is built on an estimate of the probability of detection, using genetic algorithms. Numerical examples show that the use of the optimal filter allows to find damage of a magnitude several times smaller.

The multiple regression analysis and path analysis in each dominant area of noise source are conducted to analyze the relationship between dependent variables like annoyance and independent ones such as noise and non-noise factors. The multiple regression analysis shows that impact of noise factors is the highest to annoyance in dominant areas of road traffic and railway noise.Meanwhile, impact of non-noise factors such as sensitivity and satisfaction of environment on annoyance is also high in these areas. The path analysis result for multivariate analysis between various independent and dependent variables is similar to that of the multiple regression analysis.

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Transparent type noise barrier is a desirable facility since it provides a secure view to drivers and passengers. However, reflection from this type of barrier could annoy dwellers on the sides of the road. To reduce reflection noise by transparent type barrier, modification can be made to the shapes on the front side and hence get effects by distortion of sound transmission. To achieve this, we have conducted simulation by which the effects of patterned screens of noise barrier on high-ways were investigated. The reduction effects of reflected sounds were evaluated for swelling, swelling with curved, rectangular and V-shaped screen type barriers, compared to the planar panel. The emitting noise was generated by 6-lane road and the patterned noise barriers had shown the reduction effects, especially in swelling and swelling with curved type for middle height dwellers, and the V-shaped screen type for higher elevation dweller. The swelling-type showed a decrease of 0.7~1.2 dB, performing the best diminution effect among the tested noise barriers.