Recursive estimation of exponential signals in impulsive noise using M-estimation

The 47th Midwest Symposium on Circuits and Systems Conference, Salt Lake City, Utah, USA, 25-28 July 2004This paper proposes a robust method for recursive estimating the frequencies and amplitudes of an exponential signal model under impulsive noise. Using the concept of M-estimation, a recursive algorithm based on the recursive least M-estimate (RLM) is developed. Simulation results show that the proposed method performs better than that of the conventional least square method under impulsive noise environment. The algorithm also possesses low arithmetic complexity due to its recursive nature.published_or_final_versio

Accuracy of Singularity Expansion Method in Time and Frequency Domains to Characterize Antennas in Presence of Noise

International audienceIn this paper, the accuracy of the singularity expansion method (SEM) used for antenna characterization is investigated. A well-known limitation of the SEM is that pole extraction is very sensitive to noise. A comparison between two main methods of pole extraction is presented. The matrix pencil (MP) method and the Cauchy's method are used to extract poles from the radiated fields of a dipole antenna and two bowtie antennas. Results are presented for simulated fields, and the robustness to a white Gaussian noise is also analyzed. We show that the MP method allows working with lower SNR than Cauchy's method and is more accurate for field reconstruction

Numerical methods for calculating poles of the scattering matrix with applications in grating theory

Waveguide and resonant properties of diffractive structures are often explained through the complex poles of their scattering matrices. Numerical methods for calculating poles of the scattering matrix with applications in grating theory are discussed. A new iterative method for computing the matrix poles is proposed. The method takes account of the scattering matrix form in the pole vicinity and relies upon solving matrix equations with use of matrix decompositions. Using the same mathematical approach, we also describe a Cauchy-integral-based method that allows all the poles in a specified domain to be calculated. Calculation of the modes of a metal-dielectric diffraction grating shows that the iterative method proposed has the high rate of convergence and is numerically stable for large-dimension scattering matrices. An important advantage of the proposed method is that it usually converges to the nearest pole.Comment: 9 pages, 2 figures, 4 table

Long-term loading effect on vibration performance of CLT floors: An 896-day monitoring study

Timber, a viscoelastic material, undergoes deformation over time when exposed to sustained loads, a process known as creep. Its rising popularity as a construction material, especially for timber floors, is notable. However, the influence of creep on the dynamic characteristics of timber floors, such as their natural frequency and vibration response, is not well studied. This research focused on how long-term loading (creep) affects the vibration behaviours of a cross-laminated timber (CLT) floor. A full-scale CLT floor was constructed in a lab and subjected to long-term loading using sandbags. Over 896 days, the centroid point deflection and environmental conditions (temperature and relative humidity) were monitored. Human-induced vibration tests were carried out at the beginning, throughout, and at the end of this period. The vibration response, measured in terms of the Vibration Dose Value (VDV), was assessed at various stages of long-term loading. The findings showed a moderate positive correlation between the creep deflection and environmental conditions. The fundamental frequency slightly increased over time due to creep, and a general decrease in VDV was observed as the creep advanced