Neural networks application to reduction of train caused distortions in magnetotelluric measurement data

Artificial intelligence methods for MT data processing are proposed. Distortions having a complex structure created by external artificial sources such as, for example, passing train were investigate. In the first part of this paper the time intervals with such type of distortions were found by using a special neuronal system. Next for time intervals found in the first stage the measure curve fragment is removed and then it is replied by the fragment created by a trained perceptron. The experiment showed that used method are effective

An application of the NSGA-II algorithm in Pareto joint inversion of 2D magnetic and gravity data

Joint inversion is a widely used geophysical method that allows model parameters to be obtained from the observed data. Pareto inversion results are a set of solutions that include the Pareto front, which consists of non-dominated solutions. All solutions from the Pareto front are considered the most feasible models from which a particular one can be chosen as the final solution. In this paper, it is shown that models represented by points on the Pareto front do not reflect the shape of the real model. In this contribution, a collective approach is proposed to interpret the geometry of models retrieved in inversion. Instead of choosing single solutions from the Pareto front, all obtained solutions were combined in one “heat map”, which is a plot representing the frequency of points belonging to all returned objects from the solution set. The conducted experiment showed that this approach limits the problem of equivalence and is a promising way of representing the geometry of the model that was retrieved in the inversion process

On obtaining effective elasticity tensors with entries zeroing method

The purpose of this paper is to propose a new method for obtaining tensors expressing certain symmetries, called effective elasticity tensors, and their optimal orientation. The generally anisotropic tensor being the result of in situ seismic measurements describes the elastic properties of a medium. It can be approximated with a tensor of a specific symmetry class. With a known symmetry class and orientation, one can better describe geological structure elements like layers and fissures. A method used to obtain effective tensor in the previous papers (i.e. Danek & Slawinski 2015) is based on minimizing the Frobenius norm between the measured and effective tensor of a chosen symmetry class in the same coordinate system. In this paper, we propose a new approach for obtaining the effective tensor with the assumption of a certain symmetry class. The entry zeroing method assumes the minimization of the target function, being the measure of similarity with the form of the effective tensor for the specific class. The optimization of orientation is made by means of the Particle Swarm Optimization (PSO) algorithm and transformations were parameterised with quaternions. To analyse the obtained results, the Monte-Carlo method was used. After thousands of runs of PSO optimization, values of quaternion parts and tensor entries were obtained. Then, thousands of realizations of generally anisotropic tensors described with normal distributions of entries were generated. Each of these tensors was the subject of separate PSO optimization, and the distributions of rotated tensor entries were obtained. The results obtained were compared with solutions of the method based on the Frobenius distances (Danek et al. 2013)

Zanieczyszczenie atmosfery przez zakłady przemysłowe położone w północnej części Wyżyny Śląskiej zapisane w przyrostach rocznych sosny zwyczajnej

Pines growing close to Tarnowskie Góry Chemical Plant and Miasteczko Śląskie Zinc Foundry produced reduced tree rings from 1950 to 1990 when compared with pines growing 60 km from the factories. Tree ring reductions occurred concurrently with the operation of the chemical plant and zinc foundry. Ring widths of the sampled pines are inversely proportional to the sulphur dioxide emissions from the Miasteczko Śląskie Zinc Foundry and the volume of production in the Tarnowskie Góry Chemical Plant. This demonstrates that the growth of trees was suppressed by emissions from the factories. Pines growing close to the zinc foundry started to produce reduced rings in 1965 and tree rings were very heavily suppressed in the 1970s. Reductions were noted from the time when the zinc foundry started to operate up until the present day. Reduced rings in 2000–2009 are produced by pines growing close to the zinc foundry and also those growing at a distance of 60 km from it. This indicates that ring reductions in 2000–2009 are not necessarily the effect of pollution emissions by the foundry. Tarnowskie Góry Chemical Plant emitted atmospheric pollution as early as 1925–1930 and as a result large tree ring reductions and many missing rings were identified in cores collected from pines growing close to the chemical plant. Tree ring reductions and missing rings occurred from 1955 to 1985 in pines growing close to the chemical plant. Pines have started to produce relatively wide rings since 1985 when the volume of production in the chemical plant rapidly decreased. This indicates that the plant reduced harmful emissions to the atmosphere from this date onwards