Full-wave-equation depth extrapolation for migration

Geophysics ◽  
2009 ◽  
Vol 74 (6) ◽  
pp. WCA121-WCA128 ◽  
Author(s):  
Kristian Sandberg ◽  
Gregory Beylkin
Keyword(s):  
Mathematical Formulation ◽  
Matrix Multiplication ◽  
Explicit Construction ◽  
Practical Implementation ◽  
Spectral Projector ◽  
Important Distinction ◽  
Full Wave ◽  
Spatial Operator ◽  
Propagating Waves ◽  
Traditional Approaches

Most of the traditional approaches to migration by downward extrapolation suffer from inaccuracies caused by using one-way propagation, both in the construction of such propagators in a variable background and the suppression of propagating waves generated by, e.g., steep reflectors. We present a new mathematical formulation and an algorithm for downward extrapolation that suppress only the evanescent waves. We show that evanescent wave modes are associated with the positive eigenvalues of the spatial operator and introduce spectral projectors to remove these modes, leaving all propagating modes corresponding to nonpositive eigenvalues intact. This approach suppresses evanescent modes in an arbitrary laterally varying background. If the background velocity is only depth dependent, then the spectral projector may be applied by using the fast Fourier transform and a filter in the Fourier domain. In computing spectral projectors, we use an iteration that avoids the explicit construction of the eigensystem. Moreover, we use a representation of matrices leading to fast matrix-matrix multiplication and, as a result, a fast algorithm necessary for practical implementation of spectral projectors. The overall structure of the migration algorithm is similar to survey sinking with an important distinction of using a new method for downward continuation. Using a blurred version of the true velocity as a background, steep reflectors can be imaged in a 2D slice of the SEG-EAGE model.

Adaptive Slicing for Fused Deposition Modeling and Practical Implementation Schemes

2012 ◽  
Vol 428 ◽  
pp. 137-140 ◽  
Author(s):  
Sarat Singamneni ◽  
Roger Anak Joe ◽  
Bin Huang
Keyword(s):  
Fused Deposition Modeling ◽  
Practical Implementation ◽  
Adaptive Slicing ◽  
Air Gaps ◽  
Fused Deposition ◽  
Heterogeneous Structures ◽  
Rapid Product Development ◽  
Deposition Modeling ◽  
Software And Hardware ◽  
Traditional Approaches

Fused Deposition Modeling (FDM) is one of the most popular Rapid Prototyping (RP) techniques. Initially used as means of producing 3D prototypes aiding in rapid product development, FDM found a significant application in medical models and with machine and material improvements is currently destined to be a true manufacturing process, challenging some of the traditional approaches. The material characteristics and part qualities however, are inferior, considering the heterogeneous structures characterized by the air gaps resulting from raster orientations. Current research is focused on improving the mesostructure through appropriate deposition schemes, adaptive slicing being one of the approaches. This paper reviews some of the adaptive slicing schemes and discusses software and hardware developments undertaken for the practical implementation of one of the schemes for producing test parts.

Watermarking Techniques for DRM Applications

2009 ◽  
pp. 71-100
Author(s):  
Alessandro Piva ◽  
Roberto Caldelli ◽  
Alessia De Rosa ◽  
Mauro Barni ◽  
Vito Cappellini
Keyword(s):  
Digital Watermarking ◽  
Digital Image ◽  
Spread Spectrum ◽  
Image Watermarking ◽  
Mathematical Formulation ◽  
Multimedia Content ◽  
Practical Implementation ◽  
Digital Image Watermarking ◽  
Spread Spectrum Watermarking ◽  
Watermarking Scheme

The need to safeguard the property rights of multimedia content from unauthorized copying and the possibility to determine the true owners of the asset can be faced by resorting to efficient digital watermarking systems. This chapter presents a mathematical formulation to define a digital watermarking system and describes the general requirements to be satisfied, with more emphasis given to the aspects of security, robustness, and imperceptibility. After this general discussion, the two main classes of digital watermarking schemes, namely the spread-spectrum watermarking and the side-informed watermarking are explained by highlighting their main advantages and drawbacks. This analysis is completed by the description of a practical implementation of a digital image watermarking scheme. Finally, the use of watermarking systems in the framework of a DRM is deeply analyzed.

scholarly journals The Impact of Monetary Policy on the Financial Stability of the Banking System: Setting a Modeling Problem

2021 ◽  
Vol 2 (517) ◽  
pp. 81-88
Author(s):  
A. D. Pilko ◽  
◽  
V. R. Kramar ◽  
Keyword(s):  
Monetary Policy ◽  
Financial Stability ◽  
Inflation Targeting ◽  
Banking System ◽  
Practical Implementation ◽  
Development Scenarios ◽  
Dynamic Stochastic ◽  
Low Efficiency ◽  
Traditional Approaches ◽  
The Impact

The publication is concerned with highlighting the results of the carried out analysis of the existing practice of developing macroeconomic models directed towards determining the main parameters of monetary policy of central banks, as well as assessing their impact on the indicators of financial stability of the banking system. Given the low efficiency of the traditional approaches to the formation of the monetary rule both in countries with developed market economies and in countries with small open economies (in particular, Taylor rule), possible ways to solve this problem are proposed taking into account the existing experience in shaping monetary policy parameters in the context of inflation targeting, which is already available at the NBU. The strengths and weaknesses of the main approaches to the modeling of the monetary transmission mechanism, as well as the forecasting of its impact on the financial stability of the banking system, which are used in the formation of basic and auxiliary models of the central bank, are analyzed. Particular attention is paid to structural econometric models, vector autoregression models and dynamic stochastic models of general equilibrium. As a result, a possible variant for developing an approach to macroeconomic modeling is proposed, in the framework of which assessment and analysis of the impact of monetary policy on the indicators of financial stability of the banking system is envisaged. The practical implementation of this approach makes it possible to develop models for assessing and analyzing the efficiency of the current monetary policy, projecting macroeconomic development scenarios in the short and medium term, which will both directly and indirectly determine the indicators of financial stability of the banking system.

APPLICATION OF VIRTUAL INSTRUMENTS TECHNOLOGY IN AN AUTOMATED TEST BENCH FOR MEASURING PARAMETERS OF AIR TRAFFIC CONTROL TRANSPONDERS

2021 ◽  
Author(s):  
П.И. СИМОНОВ ◽  
А.А. КОСТЮК ◽  
А.А. МАКАРЕНКО
Keyword(s):  
Traffic Control ◽  
Air Traffic Control ◽  
Test Bench ◽  
Air Traffic ◽  
Practical Implementation ◽  
Digital Instrumentation ◽  
Automated Test ◽  
Computer Based ◽  
Traditional Approaches ◽  
Measuring Bench

Дана оценка использования цифровой контрольно-измерительной аппаратуры при проверке авиационных систем в соответствии с руководящими документами ARP4754 и DO-178C. Указано, что в автоматизированных стендах на основе ЭВМ, в отличие от традиционных подходов, повышается роль программного обеспечения (ПО). Приведен обзор существующих ре -шений для проверки приемоответчиков управления воздушным движением (УВД). Сделан вывод о необходимости доработки автоматизированного измерительного стенда проверки бортовых систем предупреждения столкновений (БСПС) с целью оценки параметров приемоответчиков УВД на стадиях их разработки и проведения сертификационных работ в соответствии с DO-181E. Сформированы требования к ПО. Представлены результаты практической реализации автоматизированного измерительного стенда. An assessment of the use of digital instrumentation equipment for testing airborne systems under the guidelines ARP 4754 and DO-178C is given. It is shown that in the computer-based automated test bench, unlike traditional approaches, the importance of software increases. An overview of existing solutions for testing air traffic control (ATC) transponders is provided. It is concluded that it is necessary to refine the automated measuring bench for testing the airborne traffic collision avoidance systems (TCAS) to assess the parameters of ATC transponders at the stages of their development and certification under the guideline DO-181E. Software requirements are formed. The results of the practical implementation of an automated measuring stand are presented.

scholarly journals Response of OH airglow emissions to mesospheric gravity waves and comparisons with full-wave model simulation at a low-latitude Indian station

2016 ◽  
Vol 16 (9) ◽  
pp. 5611-5621 ◽  
Author(s):  
Rupesh N. Ghodpage ◽  
Michael P. Hickey ◽  
Alok K. Taori ◽  
Devendraa Siingh ◽  
Parashram T. Patil
Keyword(s):  
Model Simulation ◽  
Wave Model ◽  
Short Wave ◽  
Low Latitude ◽  
Full Wave ◽  
Short Period ◽  
Propagating Waves ◽  
The Mean ◽  
Wave Induced ◽  
Indian Station

Abstract. Quasi-monochromatic gravity-wave-induced oscillations, monitored using the mesospheric OH airglow emission over Kolhapur (16.8° N, 74.2° E), India, during January to April 2010 and January to December 2011, have been characterized using the Krassovsky method. The nocturnal variability reveals prominent wave signatures with periods ranging from 5.2 to 10.8 h as the dominant nocturnal wave with embedded short-period waves having wave periods of 1.5–4.4 h. The results show that the magnitude of the Krassovsky parameter, viz. |η|, ranged from 2.1 to 10.2 h for principal or long nocturnal waves (5.2–10.8 h observed periods), and from 1.5 to 5.4 h for the short waves (1.5–4.4 h observed periods) during the years of 2010 and 2011, respectively. The phase (i.e., Φ) values of the Krassovsky parameters exhibited larger variability and varied from −8.1 to −167°. The deduced mean vertical wavelengths are found to be approximately −60.2 ± 20 and −42.8 ± 35 km for long- and short-period waves for the year 2010. Similarly, for 2011 the mean vertical wavelengths are found to be approximately −77.6 ± 30 and −59.2 ± 30 km for long and short wave periods, respectively, indicating that the observations over Kolhapur were dominated by upward-propagating waves. We use a full-wave model to simulate the response of OH emission to the wave motion and compare the results with observed values.

Full-wave-equation depth extrapolation for migration using matrix multiplication

Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. S395-S403
Author(s):  
Jiachun You ◽  
Junxing Cao
Keyword(s):  
Wave Equation ◽  
Data Storage ◽  
Matrix Multiplication ◽  
Evanescent Waves ◽  
Lateral Velocity ◽  
Full Wave ◽  
Time Migration ◽  
Imaging Result ◽  
Extrapolation Scheme ◽  
Migration Method

To investigate wavefield depth extrapolation using the full-wave equation, we have derived a new depth extrapolation scheme for migration using functions of the vertical wavenumber. We develop a complete matrix multiplication formulation and approach to calculate the related mathematical functions of the vertical wavenumber and perform depth extrapolation using matrix multiplication only. Because our depth extrapolation algorithm involves only matrix multiplication, it is naturally applicable to parallel computations. Impulse response experiments demonstrate that our proposed migration method can achieve the same accuracy as full-wave-equation migration using the finite-difference method, in terms of phase information, even for media with strong lateral velocity changes. In numerical experiments using a smoothed version of the 2D SEG/EAGE salt model, our migration method provides an equivalent imaging result compared with reverse time migration (RTM) and a more accurate imaging result than migration using one-way propagators. Our method has certain potential advantages over RTM using the same full-wave equation with fewer internal multiple scatterings and fewer data storage requirements. Our adopted method is a stable depth extrapolation scheme because the evanescent waves are well suppressed. The numerical experimental results on the synthetic model demonstrate the importance of suppressing evanescent waves in a full-wave-equation-based depth extrapolation scheme and migration for imaging quality and computation cost.

scholarly journals Traditions and Novelties of Judicial Administration in the Course of Provision of Cassation and Appeal against Court Judgments in the Courts of General Jurisdiction

2021 ◽  
Vol 1 ◽  
pp. 38-43
Author(s):  
Natalya A. Latysheva ◽  
Keyword(s):  
Practical Implementation ◽  
Electronic Document ◽  
Appellate Courts ◽  
Information Transparency ◽  
Progressive Development ◽  
Judicial Administration ◽  
Long Time ◽  
Document Flow ◽  
Court Proceedings ◽  
Traditional Approaches

The practical implementation of the idea of creating cassation and appellate courts of general jurisdiction has made it possible to transform the internal content of court proceedings. The surviving traditional approaches that have been tested for a long time in regional and other equivalent courts have evolved in the context of informatization and updating of procedural legislation. However, the main tasks of the progressive development of judicial administration in the course of ensuring cassation and appeal is the elimination of legal uncertainty, which is expressed in the existence of norms that contradict each other in the transition to electronic document flow, as well as the organization of an appropriate system of control over the movement of documents, in the complex of relations, the court is the first instance — the court of cassation, appeal in conditions of information transparency of judicial activity.

scholarly journals Rubrication of text information based on the voting of intellectual classifiers

2020 ◽  
Vol 15 (89) ◽  
pp. 29-36
Author(s):  
Maxim I. Dli ◽  
◽  
Olga V. Bulygina ◽  
Andrey M. Sokolov ◽  
◽  
...  
Keyword(s):  
Fuzzy Inference ◽  
Effective Interaction ◽  
Specific Model ◽  
Electronic Government ◽  
Practical Implementation ◽  
Public Authorities ◽  
Russian State ◽  
Text Information ◽  
Fuzzy Decision Trees ◽  
Traditional Approaches

The practical implementation of the concept of electronic government is one of the priorities of Russian state policy. The organization of effective interaction between authorities and citizens is an important element of this concept. In addition to providing public services, it should include the processing of electronic appeals (applications, complaints, suggestions, etc.). Research has shown that the speed and efficiency of appeal processing largely depend on the quality of determining the thematic rubric, i.e. solving the rubrication task. The analysis of citizens' appeals received by the e-mail and official websites of public authorities has revealed several specific features (small size, errors in the text, free presentation style, description of several problems) that do not allow the successful application of traditional approaches to their rubrication. To solve this problem, it has been proposed to use various methods of intellectual analysis of unstructured text data (in particular, fuzzy logical algorithms, fuzzy decision trees, fuzzy pyramidal networks, neuro-fuzzy classifi convolutional and recurrent neural networks). The article describes the conditions of the applicability of six intellectual classifiers proposed for rubricating the electronic citizens’ appeals. They are based on such factors as the size of the document, the degree of intersection of thematic rubrics, the dynamics of their thesauruses, and the amount of accumulated statistical information. For a situation where a specific model cannot make an unambiguous choice of a thematic rubric, it is proposed to use the classifier voting method, which can significantly reduce the probability of rubrication errors based on the weighted aggregation of solutions obtained by several models selected using fuzzy inference.

Ecological Adaptive Cruise Control of Plug-in Hybrid Electric Vehicle with Connected Infrastructure and On-Road Experiments

2021 ◽  
Author(s):  
Sangjae Bae ◽  
Yeojun Kim ◽  
Yongkeun (Eric) Choi ◽  
Jacopo Guanetti ◽  
Preet Gill ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Electric Vehicle ◽  
Hybrid Electric Vehicle ◽  
Mathematical Formulation ◽  
Research Problem ◽  
Practical Implementation ◽  
Mathematical Framework ◽  
Cruise Control ◽  
Energy Efficiency Improvement ◽  
Hybrid Electric

Abstract This paper examines both mathematical formulation and practical implementation of an ecological adaptive cruise controller (ECO-ACC) with connected infrastructure. Human errors are typical sources of accidents in urban driving, which can be remedied by rigorous control theories. Designing an ECO-ACC is, therefore, a classical research problem to improve safety and energy efficiency. We add two main contributions to the literature. First, we propose a mathematical framework of an online ECO-ACC for Plug-in Hybrid Electric Vehicle (PHEV). Second, we demonstrate ECO-ACC in a real-world which includes other human drivers and uncertain traffic signals on a 2.6 [km] length of the corridor with 8 signalized intersections in Southern California, USA. The demonstration results show, on average, 30.98% of energy efficiency improvement and 8.51% additional travel time.

scholarly journals Response of OH airglow emissions to the mesospheric gravity waves and its comparisons with full wave model simulation at a low latitude Indian station

2015 ◽  
Vol 15 (24) ◽  
pp. 35881-35906
Author(s):  
R. N. Ghodpage ◽  
M. P. Hickey ◽  
A. Taori ◽  
D. Siingh ◽  
P. T. Patil
Keyword(s):  
Model Simulation ◽  
Present Report ◽  
Wave Model ◽  
Short Wave ◽  
Low Latitude ◽  
Full Wave ◽  
Short Period ◽  
Propagating Waves ◽  
Wave Induced ◽  
Indian Station

Abstract. The quasi-monochromatic gravity wave induced oscillations, monitored using the mesospheric OH airglow emission over Kolhapur (16.8° N and 74.2° E), India during January to April 2010 and January to December 2011, have been characterized using the Krassovsky method. The nocturnal variability reveals prominent wave signatures with periods ranging from 5.2–10.8 h as the dominant nocturnal wave with embedded short period waves having wave periods 1.5–4.4 h. The results show that the magnitude of the Krassovsky parameter, viz., |η| ranged from 2.1 to 10.2 for principal or long nocturnal waves (5.2 to10.8 h observed periods), and, from 1.5 to 5.4 for the short waves (1.5 to 4.4 h observed periods) during the years of 2010 and 2011, respectively. The phase, i.e., Φ values of the Krassovsky parameters exhibited larger variability and varied from −8.1 to −167°. The deduced mean vertical wavelengths are found to be approximately −60.2 ± 20 and −42.8 ± 35 km for long and short wave periods for the year 2010. Similarly, for 2011 the mean vertical wavelengths are found to be approximately −77.6 ± 30 km and −59.2 ± 30 km for long and short wave periods, respectively, indicating that the observations over Kolhapur were dominated by upward propagating waves. We use a full wave model to simulate the response of OH emission to the wave motion and compare the results with observed values. In the present report, we discuss the observed wave characteristics and cause of the noted differences.

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