Random or incoherent noise is an important type of seismic noise, which can seriously affect the quality of the data. Therefore, decreasing the level of this category of NOISES is necessary for increasing the signal-to-noise ratio (SNR) of seismic records. Random NOISES and other events overlap each other in time domain, which makes it difficult to attenuate them from seismic records. In this research, a new technique is produced, by joining FX deconvolution (FXD) and a special kind of median filter in order to suppress random noise from seismic records. The technique is operated in some stages; firstly, FXD is tried to eliminate the Gaussian noise, and the median filter is fixed to diminish the spike-like noise. The synthetic dataset and field data examples (from an oil field in the southwest of Iran) have been employed to demonstrate that random noise reduction can be attained, while the signal content will not be destroyed considerably. The final results indicate the authority of the proposed strategy in suppressing random NOISES, whereas signal information is almost protected during the filtering.

The stochastic models for ship heave motion in irregular sea waves based on white and colored NOISES are examined. For this purpose the deterministic model transfers to stochastic models by adding different noise terms in force and then these models are solved analytically and numerically. Finally an investigation is undertaken to examine the parameter estimation problem of second order stochastic differential equations when some of the measurements are unavailable or missing data. Several simulation results are presented to illustrate the performance of the estimators.

The uncertainty on the values of the measured residual stresses in hole-drilling integral method, the most widely used technique for measuring residual stress, will be called hereinafter as residual stress NOISES, which initiate high sensitivity of stress to strain measurement errors due to illconditioning of inverse integral equations. This study aimed to investigate the use of Chebyshev points to decrease residual stress NOISES in the hole drilling method. The Chebyshev points were extended to hole-drilling increments from surface to specified interior depth. The bending of an aluminum beam was used to validate the extended method, and the results were compared with the standard reduction NOISES technique, Tikhonov-Morozov, and optimum steps technique. The result obtained from the extended method was shown to lead not only an accurate determination of de-noised residual stress, but also a simple calculation procedure in comparison with the Tikhonov-Morozov and optimal steps method. The results indicate that the use of modified Chebyshev points decreased the mean absolute error of residual stress to 8. 17 MPa from 14 MPa in Tikhonov-Morozov and 10. 52 MPa in optimum steps methods.

Along with exhaust emissions and Fuel Consumptions (FCs), noise emission from cars is one of the main concerns of automotive industry. Hybridization is a promising method to not only make automobiles more environmentally-friendly, but also reduce their noise emissions. However, a proper control design for Hybrid Electric Vehicles (HEVs) to make noise emissions lower is still required in addition to exhaust emissions and FC reductions. In this study, we modify Equivalent Consumption Minimization Strategy (ECMS) to keep the engine noise less than tire/road noise during driving. A test bench is established for calculating the engine noise and brake specific FC. Moreover, tire/road noise is experimentally defined as a function of the vehicle speed. It is shown that by implementing the basic ECMS, the engine noise exceeds the tire/road noise in some moments of driving cycle, which is annoying to the passengers. Therefore, a modified ECMS is proposed to limit the candidate engine operating points such that the engine noise does not exceed the tire/road noise. It is shown that the engine noise level is kept below the tire/road noise level by using the modified ECMS at the expense of a very small increase (about 1%) in the vehicle's FC.