223 research outputs found
5-D interpolation with wave-front attributes
No full textMost 5-D interpolation and regularization techniques reconstruct the missing data in the frequency domain by using mathematical transforms. An alternative type of interpolation methods uses wave-front attributes, that is, quantities with a specific physical meaning like the angle of emergence and wave-front curvatures. In these attributes structural information of subsurface features like dip and strike of a reflector are included. These wave-front attributes work on 5-D data space (e.g. common-midpoint coordinates in x and y, offset, azimuth and time), leading to a 5-D interpolation technique. Since the process is based on stacking next to the interpolation a pre-stack data enhancement is achieved, improving the signal-to-noise ratio (S/N) of interpolated and recorded traces. The wave-front attributes are determined in a data-driven fashion, for example, with the Common Reflection Surface (CRS method). As one of the wave-front-attribute-based interpolation techniques, the 3-D partial CRS method was proposed to enhance the quality of 3-D pre-stack data with low S/N. In the past work on 3-D partial stacks, two potential problems were still unsolved. For high-quality wave-front attributes, we suggest a global optimization strategy instead of the so far used pragmatic search approach. In previous works, the interpolation of 3-D data was performed along a specific azimuth which is acceptable for narrow azimuth acquisition but does not exploit the potential of wide-, rich- or full-azimuth acquisitions. The conventional 3-D partial CRS method is improved in this work and we call it as a wave-front-attribute-based 5-D interpolation (5-D WABI) as the two problems mentioned above are addressed. Data examples demonstrate the improved performance by the 5-D WABI method when compared with the conventional 3-D partial CRS approach. A comparison of the rank-reduction-based 5-D seismic interpolation technique with the proposed 5-DWABI method is given. The comparison reveals that there are significant advantages for steep dipping events using the 5-D WABI method when compared to the rank-reduction-based 5-D interpolation technique. Diffraction tails substantially benefit from this improved performance of the partial CRS stacking approach while the CPU time is comparable to the CPU time consumed by the rank-reduction-based method
3D wavefront attribute determination and conflicting dip processing
No full textThe knowledge of 3D wavefront attributes allows many important applications, such as stacking, 5D interpolation, 3D diffraction separation and imaging, and 3D wavefront tomography, just to name a few. For the determination of wavefront attributes, we use the common-reflection-surface (CRS) operator. We adopt a simultaneous search for the determination of wavefront attributes and combine it with conflicting dip processing. For the simultaneous search, we compare three heuristic global optimization algorithms such as particle swarm optimization (PSO), genetic algorithm (GA), and differential evolution (DE). For conflicting dip processing, a dip angle decomposition method for the probed sample is introduced and the simultaneous search is independently performed in specified dip ranges to individually obtain attributes and semblance for each range. Results for the laterally heterogeneous 3D SEG C3WA data indicate that DE has superior performance to determine the 3D wavefront attributes when compared with PSO, GA, and the conventional pragmatic approach because a higher semblance and an improved set of wavefront attributes are achieved. A comparison of the data-driven wavefront attributes obtained from the DE with the model-driven wavefront attributes computed by kinematic and dynamic ray tracing reveals the validity of the data-driven wavefront attributes. Combining the simultaneous search with conflicting dip processing for the 3D CRS stack further improved reflected energy and diffraction details when compared with results without simultaneous search and/or conflicting dip processing
Reliability of data-driven wavefront attributes in laterally heterogeneous media
No full text3D wavefront attributes play a major role in many processing steps, such as prestack data enhancement, diffraction separation, and wavefront tomography. For the determination of the 3D wavefront attributes, various stacking operators can be used by adopting semblance optimization. These operators are derived for laterally homogeneous media. In praxis, however, they are applied in real geologic environments with even strong lateral velocity variations such as salt structures. This leads to the question of the quality of the 3D wavefront attributes using these operators when determined in the presence of strong lateral velocity changes. We compared the 3D wavefront attributes determined by 3D common-reflection-surface (CRS) operator (called data-driven wavefront attributes) with the 3D wavefront attributes computed by 3D kinematic and dynamic ray tracing (called model-driven wavefront attributes). For the determination of the 3D CRS wavefront attributes, we have developed a global optimization scheme based on differential evolution. Reflection seismic data of the laterally heterogeneous 3D SEG C3WA salt model are considered, and the model-driven wavefront attributes are computed for a smoothed version of the 3D SEG salt model. The comparison reveals that the wavefront attributes for the normal-incidence-point ray indicate a very good match not only in areas of mild lateral velocity variation but even in regions with strong lateral velocity variations. Approximately 80%–90% of the total picks indicate the good match with a relative error of less than 10% when a semblance threshold of 0.1 is considered in the automatic picking process. This confirms the validity of the determined wavefront attributes even in the presence of strong lateral velocity changes. Using a higher semblance threshold in the automatic picking leads to fewer picks but with an even better match between model- and data-driven wavefront attributes
Is Hondius or Schultz the Author of the Portrait Study of Karol Ferdynand Vasa?
No full textStanding face to face with a civil war and a danger of destabilisation of the country, King Jan Kazimierz decided that a change in his official iconography was so important that almost immediately after succeeding to the throne (1648) he reorganised his artistic court. In 1649 the outstanding portrait painter Daniel Schultz was employed and he was charged with the task of creating the image of the monarch that would be suitable for the requirements of the new authorities' propaganda and at the same time would meet the society's expectations. (It was for the same reasons that the great Roman sculptor Francesco Rossi was brought to Poland in 1651.) Of the former group of artists among others Willem Hondius was kept – as it turns out not a very able draughtsman, but a good copper engraver, who proved useful in his earlier works for the royal court, and now was indispensable for putting into effect Jan Kazimierz's propaganda aims.
Analysing the portrait study of the King's brother, Karol Ferdynand Vasa (1650) from the collection of the National Museum in Gdańsk (Fig. 1), Gajewski finds in it both new principles of the art of portrait introduced into the official image by Daniel Schultz, and the artistic qualities characteristic of Schultz's painting (Fig. 2, 3). Gajewski challenges the proposition put forward in the literature of the subject saying that it is Hondius who is the author of the portrait study of Karol Ferdynand, and he claims that the author of the study is Schultz. He also thinks that the study is Schultz's drawing for the graphic portrait of Karol Ferdynand Vasa that was not used. The portrait was made (1650) by Hondius after another pattern by Daniel Schultz (Fig. 4)
Seismische Datenbearbeitung mit dem erweiterten Common Reflection Surface workflow
No full textThe so-called CRS workflow is a processing scheme for seismic data based on the kinematic wavefield attributes estimated during the Common Reflection Surface (CRS) stack, the so-called CRS attributes. I extended the CRS workflow with a multiple suppression tool and incorporated the prestack data enhancement tool by Baykulov and Gajewski (2009a). The introduced expanded CRS workflow contains a multiparameter stacking tool, the CRS stack, a multiple attenuation tool based on CRS attributes, a prestack data enhancement technique by means of partial CRS stacks, a tomographic tool also based on CRS attributes, and a subsequent time or depth migration algorithm. This quick and stable processing workflow allows to produce data of enhanced quality for reliable post- and prestack depth migrations, suppress multiple reflections in the data, and generates a velocity model for an initial depth migration. The CRS stack theory will be reviewed in the first chapter of the thesis. Afterwards, the newly developed multiple attenuation tool will be discussed in detail. Additionally, it will be also shown how the prestack data enhancement tool can be incorporated into the CRS workflow and how it serves as an interface for achieving the data condition requirements of other non CRS related methods. Furthermore, NIP-wave tomography will be discussed and compared to another tomographic tool in a complex geological setting. To illustrate the potential of this workflow, results of an imaging project on a marine industry data set from the Eastern Mediteranean / Levantine basin will be presented throughout the thesis. The results are satisfying and allowed a detailed geologic interpretation based on depth migrated sections of the data set, which is presented in the last chapter
Doświadczenia z reform fiskalnych w okresie tworzenia Unii Gospodarczej i Walutowej
No full textThe author analyzes the experience of fiscal reforms carried out in the European Union after the adoption of the Maastricht Treaty in 1992. The treaty provides for what are called convergence criteria for countries aspiring to join the eurozone. After the treaty was signed a period of fiscal adjustments began in Europe. In the following years, individual countries pursued different strategies and attained different results in the process. The article aspires to be a source of information for those seeking to develop an optimal reform strategy for Poland—now that the Polish government has clearly stated that Poland should become part of the euro zone in the future. Using statistical data, Gajewski discusses how the convergence criteria adopted in the Maastricht Treaty (reference values for the deficit and public debt) influence fiscal policy in terms of the effectiveness of the strategy for adjusting government revenue and expenditure. It turns out that the fiscal convergence criterion could increase the pro-cyclical aspect of fiscal policy in the period directly preceding the launch of the third stage of the Economic and Monetary Union and in the first few years of the system’s functioning, Gajewski says. His research confirms earlier findings that effectively bringing down the deficit below the reference level requires focusing one’s efforts on the expenditure rather than revenue side of the budget. This may be because limiting expenditure calls for more comprehensive reforms covering structural changes and increased effectiveness of available resources. According to Gajewski, countries that have met the fiscal criterion by limiting expenditure generally took longer to meet this criterion and had a higher budget balance on average, during the period of the eurozone’s functioning, than countries that focused their strategies on the revenue side of the budget and stopgap measures. The author concludesthat the adopted strategy for public finance consolidation had far-reaching consequences for the competitiveness of individual countries and may have been one of the main causes behind the crisis, which hit the eurozone in 2008
Nierównowaga finansów publicznych w krajach Unii Europejskiej
No full textThe article aims to estimate the current level of public finance sustainability in the European Union, taking into account the starting fiscal position, the possibility of withdrawing fiscal impulses, the future costs of population aging, and possible financial market responses. The author achieves this objective by using an indicator method similar to that used by the European Commission. However, this method has been modified by diversifying projected GDP growth rates and public debt interest rates, Gajewski says. The assumption is that the interest rate may vary depending on the response of financial markets to the debt-to-GDP ratio. The author demonstrates that almost all EU countries have lost their medium- and long-term fiscal sustainability. Greece and Ireland appear to be the worst off among the analyzed countries, Gajewski says. Both these economies suffer from a high structural budget deficit and potentially high costs of population aging. Most other countries will also be forced to make strong fiscal adjustments to achieve primary surpluses far exceeding those in the period before the financial crisis. The calculations also show that Sweden, Estonia and Bulgaria boast the highest levels of public finance sustainability in the European Union, the author concludes
The Economic Effects of Regional Policy
No full textThe author analyses the relationship between regional disparities and economic efficiency. He also examines the efficiency of regional policy tools in the context of regional disproportions and economic efficiency. In the first part of the paper, the author discusses the main areas of controversy concerned with the regional distribution of business activity and its influence on economic growth. Then, using a graphic model to present the theory of endogenous growth and the New Economic Geography-and additionally considering social capital-Gajewski analyzes the economic effects of interregional transfers, subsidies for enterprises, investment in transport infrastructure and innovation policy. The author concludes that regional policy measures designed to support the regional diffusion of innovation and reduce its costs are the most effective instrument of regional policy, from the perspective of economic efficiency and the need to level out regional differences. Subsidies to enterprises seem to be the least beneficial, if not harmful, regional policy tool, Gajewski says. His research findings indicate that the use of various other regional policy instruments leads to an “equity-efficiency tradeoff,” or a conflict between economic and social objectives
Public Finance Sustainability in European Union Countries
No full textThe article aims to estimate the current level of public finance sustainability in the European Union, taking into account the starting fiscal position, the possibility of withdrawing fiscal impulses, the future costs of population aging, and possible financial market responses. The author achieves this objective by using an indicator method similar to that used by the European Commission. However, this method has been modified by diversifying projected GDP growth rates and public debt interest rates, Gajewski says. The assumption is that the interest rate may vary depending on the response of financial markets to the debt-to-GDP ratio. The author demonstrates that almost all EU countries have lost their medium- and long-term fiscal sustainability. Greece and Ireland appear to be the worst off among the analyzed countries, Gajewski says. Both these economies suffer from a high structural budget deficit and potentially high costs of population aging. Most other countries will also be forced to make strong fiscal adjustments to achieve primary surpluses far exceeding those in the period before the financial crisis. The calculations also show that Sweden, Estonia and Bulgaria boast the highest levels of public finance sustainability in the European Union, the author concludes
Ekonomiczne efekty polityki regionalnej
No full textThe author analyses the relationship between regional disparities and economic efficiency. He also examines the efficiency of regional policy tools in the context of regional disproportions and economic efficiency. In the first part of the paper, the author discusses the main areas of controversy concerned with the regional distribution of business activity and its influence on economic growth. Then, using a graphic model to present the theory of endogenous growth and the New Economic Geography—and additionally considering social capital—Gajewski analyzes the economic effects of interregional transfers, subsidies for enterprises, investment in transport infrastructure and innovation policy. The author concludes that regional policy measures designed to support the regional diffusion of innovation and reduce its costs are the most effective instrument of regional policy, from the perspective of economic efficiency and the need to level out regional differences. Subsidies to enterprises seem to be the least beneficial, if not harmful, regional policy tool, Gajewski says. His research findings indicate that the use of various other regional policy instruments leads to an “equity-efficiency tradeoff,” or a conflict between economic and social objectives
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