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1

Multiples inversion imaging using a one way propagation operator

Li Qiang, Wang Deli

Acta Geophysica

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2019

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Vol. 67, no. 5

1341--1348

EN

The one-way propagation operator in the frequency-space domain has the advantages of fast calculation speed and good adaptability to medium with lateral velocity variation. The full wavefeld model constructed by the one-way propagation operator is iterative. As the number of iterations increases, the components of wavefeld are more and more abundant. In the full wavefeld model, the propagation and scattering processes are independent of each other. The former is determined by the propagation operator, while the latter is determined by the scattering operator. As each iteration increases, the wavefeld component will increase by one order. As an inverse migration operator, the full wavefeld model could feed back the imaging result to the data. By calculating the residual between the simulated data and the actual data, the refectivity is updated. This is an inversion process. In this process, multiples will be imaged. In this way, the subsurface information contained in multiples is utilized and the imaging quality is greatly improved. The L1-norm is used to constrain the imaging result, which further suppresses the artifacts and improves the imaging resolution. We have made some numerical examples in 2D case, explaining the principles and advantages of this methodology.

2

Complex Ranking Procedures

Sandrasagra B., Soltys M.

Fundamenta Informaticae

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2016

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Vol. 144, nr 3/4

223--240

EN

We propose a research program for developing a formal framework for ranking procedures based on the Pairwise Comparisons method. We are interested in the case where relatively few items are to be ranked with a complex procedure and according to a large number of criteria. A typical example of this scenario is a competition where several companies bid for a contract, and where the selection of the winner is done with multiple criteria according to an intricate selection procedure. Several other applications are suggested.

3

Availability of WDM Multi Ring Networks

Rados I., Rados K.

Journal of Telecommunications and Information Technology

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2015

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nr 1

53--58

EN

This paper presents a new approach to modeling the availability of the networks composed of multiple interconnected rings in two nodes. For availability modeling method algebraic formulation is used. Using this method, through the availability of multiple ring networks consisting of two and three-rings connected to two nodes, a general expression for the availability between two terminals of multiple ring networks is derived. To perform the expression some real assumptions were taken and the analytical calculation showed that the use of these expressions under these assumptions provides real values for availability between the two terminals of multiple ring networks. Information on the availability of links and nodes is taken from previously published works.