Gabor Korvin - Academia.edu (original) (raw)

Papers by Gabor Korvin

Encyclopedia of earth sciences, Dec 5, 2020

Proceedings, May 4, 2010

s method is costly and time consuming.To correlate reservoir properties with the continuously rec... more s method is costly and time consuming.To correlate reservoir properties with the continuously recorded well log data geologists generally use linear or non-linear regressions. This talk reports a comparative study of two types of neural networks, a Multiple-Layer Perception MLP, and a General Regression Neural Network GRNN. The viability of these techniques are demonstrated on log data and seismic from a reservoir in south of Algeria. This study utilizes the basic logs (GR, DT, VSH, RHOB, LLD and NPHI and five attributes to predict porosity, permeability and lithofacies in cored and uncored wells. The agreement between the core data and the predicted values by neural networks demonstrate a successful implementation and validation of the network’s ability to map a complex non-linear relationship between well logs and permeability and porosity. Also the results show that the application of the General Regression Neural Network GRNN gives a relatively better performance than the Multiple-Layer Perception MLP.

Geoexploration, Jun 1, 1982

The paper is addressed to the following problem, frequently occurring in geophysics, rock physics... more The paper is addressed to the following problem, frequently occurring in geophysics, rock physics and solid state physics. Suppose we are given a composite material of volume V consisting of two phases of the respective volume fractions P, Q; P + Q = V, and suppose these constituents are uniformly distributed within the total volume. Suppose g is some physically measurable property that assumes the values g, and g,, respectively, for the two constituents, and a value 2 for the composite. Suppose, further, that the value of 2 is unambiguously determined by the volume fractions P, Q and the specific properties g,, g, :

Encyclopedia of earth sciences, 2023

Encyclopedia of earth sciences, 2023

Encyclopedia of earth sciences, 2023

Geophysics, Sep 1, 1981

In his recent paper Dr. Armstrong proposes a novel approach based on considerations of thermal co... more In his recent paper Dr. Armstrong proposes a novel approach based on considerations of thermal conduction and thermoelastic dissipation to explain the observed nearly constant Q behavior toward low frequencies in randomly heterogeneous solids. I feel, however, the fluctuation coefficient R defined by his equation (22) does have an inherent frequency dependence introduced through the f2(δi) factors so that the attenuation coefficient A might be a more complicated function of frequency than suggested by equation (24).

Springer eBooks, Dec 8, 2021

In the electronic acquisition of geoscientific data, and their subsequent digital processing, we ... more In the electronic acquisition of geoscientific data, and their subsequent digital processing, we frequently subject the data to Gain Control which is a nonlinear transformation to maintain an approximately stationary signal of a prescribed Root Mean Square (RMS) amplitude at its output, despite time-dependent slow variations of the signal amplitude level at the input. In simple terms, Gain Control reduces the signal if it is strong and amplifies it when it is weak. There are two ways to control signal amplitude, automatically or in a preset, programmed manner. Automatic Gain Control (AGC, also called Automatic Volume Control AVC, Automatic Level Control ALC, Time-Varying Gain TGC) is realized by an algorithm where the output energy level in a sliding time-window controls the gain applied to the input to keep it within prescribed limits. Programmed Gain Control (PGC) applies a gain which is a function of record time and was determined beforehand. In some AGC or PGC systems the gain can only vary by a factor of two (Binary Gain Control BGC). Gain Control (AGC or PGC) is an important step of data processing to improve the visibility of such data where propagation effects (such as attenuation or spherical divergence) have caused amplitude decay, and to assure approximate stationarity which is a prerequisite for statistical time-series analysis.

Encyclopedia of earth sciences, 2023

Hamdard Islamicus, Dec 31, 2018

DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2019

Arabian Journal of Geosciences, Feb 12, 2013

Arabian journal for science and engineering, Apr 19, 2016

The Kozeny-Carman and Timur-type equations 1 connecting porosity and permeability contain rock-te... more The Kozeny-Carman and Timur-type equations 1 connecting porosity and permeability contain rock-textural 2 constants such as tortuosity and specific surface area. Some-3 times these are combined in single factors as Kozeny constant 4 or flow zone index. The partial differential equations of flow 5 in triple-porosity rocks contain transfer factors, interporos-6 ity flow shape factors between different kinds of pores, as 7 well as their individual storativities. Without knowing these 8 constants, no meaningful permeability prediction or flow 9 simulation is possible. The paper reviews the main ideas of 10 how to find such rock-textural properties directly from the 11 microscopic image.

Geophysical Journal International, Mar 1, 1990

The spatial distribution of the South Australian gravity station network (over 65 OOO stations) c... more The spatial distribution of the South Australian gravity station network (over 65 OOO stations) can be approximated by a fractal point set of correlation dimension 0, = 1.4. The fractality is established over more than 2 decades of distance. The fractal nature of the grid is possibly due to the multistage decisions involved in establishing a network; in each step, previously unexplored areas are dissected by geophysical traverses, as in the classical fractal fragmentation process. It is shown that we cannot observe the short-wavelength components of the gravity field if the dimension of the network is less than two and any attempt to interpolate onto a regular grid could lead to spurious anomalies due to aliasing.

Chaos Solitons & Fractals, Mar 15, 2003

Kybernetes, Feb 1, 2002

Pervasive complementarity among agents, variables and their relations is a strong manifestation o... more Pervasive complementarity among agents, variables and their relations is a strong manifestation of unity in the real world. It is explained in various ways within scientific systems and in alternative ways of viewing resource allocation from that in neoclassical economic theory and its various prototypes. Complementarity among goods, services and factors in neoclassical resource allocation is simply a localized phenomenon. Despite this, bundles of similar goods collect together to re-establish marginal substitution with other bundles. In systems science, the cessation of complementarity among variables causes the demise of process. Indeed, the most significant influence of economic complementarity is to be found in decision-making systems. Here strongly interactive ethical principles showing pervasive and strong complementarity reveal themselves. Hence a knowledge-induced scientific methodology emerges. Yet these scientific dynamic methods that are merely premised on time-phase, are found to be inadequate in explaining pervasive interactions. Instead, simulation methods reveal important and interesting results premised on the epistemological premise of systemic unity and interactions. We will examine these questions in this paper with respect to the optimal control problem of the calculus of variations, and for multi-objective decision problems.

Birkhäuser Basel eBooks, 1989

ABSTRACT Recent geophysical studies revealed that the Palaeozoic basement of the Gulf of Suez con... more ABSTRACT Recent geophysical studies revealed that the Palaeozoic basement of the Gulf of Suez consists of an enormous number of fault blocks whose network qualitavely resembles the contraction-crack polygons which can be found in nature in a wide variety of materials and on all scales (mud cracks, hardening concrete, age cracking in paintings,etc.). The fault network of the Gulf of Suez basement forms a rather uniformly spaced polygonal pattern, most of the blocks are four-sided, the lengths of block sides parallel with the Gulf of Suez axis are exponentially distributed. The power-law size distribution associated with the fractal (scale-free) fragmentation can be possibly ruled out.The paper calls attention to the necessity of calssifying the physical processes leading to fragmentations with exponential-, lognormal-, and power-law size distributions, respectively.

IEEE Geoscience and Remote Sensing Letters, Oct 1, 2005

This letter generalizes Pentland's result about the fractal dimension of the optical image of rou... more This letter generalizes Pentland's result about the fractal dimension of the optical image of rough natural surfaces, without imposing his requirement that the reflection is Lambertian. Instead, it is assumed that the reflectance coefficient is proportional to the focusing/defocusing due to local surface curvature. It will be proved for this case that the density distribution across the optical image inherits the fractal dimension of the mapped surface.

Encyclopedia of earth sciences, Dec 5, 2020

Proceedings, May 4, 2010

s method is costly and time consuming.To correlate reservoir properties with the continuously rec... more s method is costly and time consuming.To correlate reservoir properties with the continuously recorded well log data geologists generally use linear or non-linear regressions. This talk reports a comparative study of two types of neural networks, a Multiple-Layer Perception MLP, and a General Regression Neural Network GRNN. The viability of these techniques are demonstrated on log data and seismic from a reservoir in south of Algeria. This study utilizes the basic logs (GR, DT, VSH, RHOB, LLD and NPHI and five attributes to predict porosity, permeability and lithofacies in cored and uncored wells. The agreement between the core data and the predicted values by neural networks demonstrate a successful implementation and validation of the network’s ability to map a complex non-linear relationship between well logs and permeability and porosity. Also the results show that the application of the General Regression Neural Network GRNN gives a relatively better performance than the Multiple-Layer Perception MLP.

Geoexploration, Jun 1, 1982

The paper is addressed to the following problem, frequently occurring in geophysics, rock physics... more The paper is addressed to the following problem, frequently occurring in geophysics, rock physics and solid state physics. Suppose we are given a composite material of volume V consisting of two phases of the respective volume fractions P, Q; P + Q = V, and suppose these constituents are uniformly distributed within the total volume. Suppose g is some physically measurable property that assumes the values g, and g,, respectively, for the two constituents, and a value 2 for the composite. Suppose, further, that the value of 2 is unambiguously determined by the volume fractions P, Q and the specific properties g,, g, :

Encyclopedia of earth sciences, 2023

Encyclopedia of earth sciences, 2023

Encyclopedia of earth sciences, 2023

Geophysics, Sep 1, 1981

In his recent paper Dr. Armstrong proposes a novel approach based on considerations of thermal co... more In his recent paper Dr. Armstrong proposes a novel approach based on considerations of thermal conduction and thermoelastic dissipation to explain the observed nearly constant Q behavior toward low frequencies in randomly heterogeneous solids. I feel, however, the fluctuation coefficient R defined by his equation (22) does have an inherent frequency dependence introduced through the f2(δi) factors so that the attenuation coefficient A might be a more complicated function of frequency than suggested by equation (24).

Springer eBooks, Dec 8, 2021

In the electronic acquisition of geoscientific data, and their subsequent digital processing, we ... more In the electronic acquisition of geoscientific data, and their subsequent digital processing, we frequently subject the data to Gain Control which is a nonlinear transformation to maintain an approximately stationary signal of a prescribed Root Mean Square (RMS) amplitude at its output, despite time-dependent slow variations of the signal amplitude level at the input. In simple terms, Gain Control reduces the signal if it is strong and amplifies it when it is weak. There are two ways to control signal amplitude, automatically or in a preset, programmed manner. Automatic Gain Control (AGC, also called Automatic Volume Control AVC, Automatic Level Control ALC, Time-Varying Gain TGC) is realized by an algorithm where the output energy level in a sliding time-window controls the gain applied to the input to keep it within prescribed limits. Programmed Gain Control (PGC) applies a gain which is a function of record time and was determined beforehand. In some AGC or PGC systems the gain can only vary by a factor of two (Binary Gain Control BGC). Gain Control (AGC or PGC) is an important step of data processing to improve the visibility of such data where propagation effects (such as attenuation or spherical divergence) have caused amplitude decay, and to assure approximate stationarity which is a prerequisite for statistical time-series analysis.

Encyclopedia of earth sciences, 2023

Hamdard Islamicus, Dec 31, 2018

DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2019

Arabian Journal of Geosciences, Feb 12, 2013

Arabian journal for science and engineering, Apr 19, 2016

The Kozeny-Carman and Timur-type equations 1 connecting porosity and permeability contain rock-te... more The Kozeny-Carman and Timur-type equations 1 connecting porosity and permeability contain rock-textural 2 constants such as tortuosity and specific surface area. Some-3 times these are combined in single factors as Kozeny constant 4 or flow zone index. The partial differential equations of flow 5 in triple-porosity rocks contain transfer factors, interporos-6 ity flow shape factors between different kinds of pores, as 7 well as their individual storativities. Without knowing these 8 constants, no meaningful permeability prediction or flow 9 simulation is possible. The paper reviews the main ideas of 10 how to find such rock-textural properties directly from the 11 microscopic image.

Geophysical Journal International, Mar 1, 1990

The spatial distribution of the South Australian gravity station network (over 65 OOO stations) c... more The spatial distribution of the South Australian gravity station network (over 65 OOO stations) can be approximated by a fractal point set of correlation dimension 0, = 1.4. The fractality is established over more than 2 decades of distance. The fractal nature of the grid is possibly due to the multistage decisions involved in establishing a network; in each step, previously unexplored areas are dissected by geophysical traverses, as in the classical fractal fragmentation process. It is shown that we cannot observe the short-wavelength components of the gravity field if the dimension of the network is less than two and any attempt to interpolate onto a regular grid could lead to spurious anomalies due to aliasing.

Chaos Solitons & Fractals, Mar 15, 2003

Kybernetes, Feb 1, 2002

Pervasive complementarity among agents, variables and their relations is a strong manifestation o... more Pervasive complementarity among agents, variables and their relations is a strong manifestation of unity in the real world. It is explained in various ways within scientific systems and in alternative ways of viewing resource allocation from that in neoclassical economic theory and its various prototypes. Complementarity among goods, services and factors in neoclassical resource allocation is simply a localized phenomenon. Despite this, bundles of similar goods collect together to re-establish marginal substitution with other bundles. In systems science, the cessation of complementarity among variables causes the demise of process. Indeed, the most significant influence of economic complementarity is to be found in decision-making systems. Here strongly interactive ethical principles showing pervasive and strong complementarity reveal themselves. Hence a knowledge-induced scientific methodology emerges. Yet these scientific dynamic methods that are merely premised on time-phase, are found to be inadequate in explaining pervasive interactions. Instead, simulation methods reveal important and interesting results premised on the epistemological premise of systemic unity and interactions. We will examine these questions in this paper with respect to the optimal control problem of the calculus of variations, and for multi-objective decision problems.

Birkhäuser Basel eBooks, 1989

ABSTRACT Recent geophysical studies revealed that the Palaeozoic basement of the Gulf of Suez con... more ABSTRACT Recent geophysical studies revealed that the Palaeozoic basement of the Gulf of Suez consists of an enormous number of fault blocks whose network qualitavely resembles the contraction-crack polygons which can be found in nature in a wide variety of materials and on all scales (mud cracks, hardening concrete, age cracking in paintings,etc.). The fault network of the Gulf of Suez basement forms a rather uniformly spaced polygonal pattern, most of the blocks are four-sided, the lengths of block sides parallel with the Gulf of Suez axis are exponentially distributed. The power-law size distribution associated with the fractal (scale-free) fragmentation can be possibly ruled out.The paper calls attention to the necessity of calssifying the physical processes leading to fragmentations with exponential-, lognormal-, and power-law size distributions, respectively.

IEEE Geoscience and Remote Sensing Letters, Oct 1, 2005

This letter generalizes Pentland's result about the fractal dimension of the optical image of rou... more This letter generalizes Pentland's result about the fractal dimension of the optical image of rough natural surfaces, without imposing his requirement that the reflection is Lambertian. Instead, it is assumed that the reflectance coefficient is proportional to the focusing/defocusing due to local surface curvature. It will be proved for this case that the density distribution across the optical image inherits the fractal dimension of the mapped surface.

In geoscientific signal processing, a digital filter is a system 8 (usually a time-invariant, lin... more In geoscientific signal processing, a digital filter is a system 8 (usually a time-invariant, linear operator realized by a com-9 puter program) that performs mathematical operations on a 10 sampled, discrete-time signal to reduce certain aspects and/or 11 enhance certain other aspects of that signal. The term "digi-12 tal" is meant in contrast with the other major type of filters, the 13 analog filter, which is used during signal-recording and is 14 typically realized by an electronic circuit operating on

Unpublished, 2022

In this study I discuss twenty-three Arabic motifs in Borges’s texts and trace them back to their... more In this study I discuss twenty-three Arabic motifs in Borges’s texts and trace them back to their most
likely sources. Borges did not know Arabic, and gained his knowledge of the Orient from secondary
sources, books by Burton, Lane, Palacios and others. In many cases Borges playfully changed these
Arabic motifs, or invented new ones. In the rare occasions when he gave his sources, these were as
fantastic as the stories themselves: references to non-existing tomes by non-existing scholars, to an
odd book of Burton (instead of the correct one by Lane), or to an out-of-context citation from Gibbon.
I succeeded in locating the sources of most of these motifs, and proved for a few others that they are
inventions of Borges. I could not find the source of one poem. For one motif (“Iskander’s mirror”) I
could only show that it is well-documented in Oriental literature, but I could not find any likely source
where Borges could have learned about it.

Unpublished, 2020

In India, Urdu ghazals are published in Dēvanāgarī, transliterated from Perso-Arabic nastaliq scr... more In India, Urdu ghazals are published in Dēvanāgarī, transliterated from Perso-Arabic nastaliq script. This paper studies the accuracy of these transliterations, by comparing 152 poems (2734 lines) from seven poets, including Jaipur-based Urdu poet Parsā Kaūsarī Jaipūri (1922-1999) whose hitherto unknown Urdu manuscript containing his Collected Poems is introduced and described. Word-byword comparison detected that in 113 out of 2734 lines the original and transliterated texts slightly differed. As the Hindi and Urdu languages are almost identical in their vocabulary and grammar, rewriting an Urdu nastaliq text in to Dēvanāgarī is a special case of domestication , that is a strategy of making the target text closely conform to the pronunciation, orthography and grammar of the Hindi language. For the lay reader such "Urduin-Dēvanāgarī" reproductions of the Urdu ghazals are useful, satisfactory and preserve their esthetic value, but to avoid loss of information from the source text, it is recommended that definitive, scientific editions of Urdu ghazals should always be published in both scripts en face, with the rare Urdu words explained in footnotes.

Never published or presented at conference

Applying a fractal model for the interpretation of a well-pressure curve

Australian linguist Jane Simpson (2000) proved that the Afghan camel drivers had become an active... more Australian linguist Jane Simpson (2000) proved that the Afghan camel drivers had become an active vector in the diffusion of Pidgin English among Aboriginal people. The present paper claims, that along the camel tracks the Afghans also distributed the most precious jewels of their cargo: their Islamic faith and a personal example of Muslim life style. They were no just transporters of railway sleepers and wool, but also "Islam-carriers", a vector-of historic significance-in the diffusion of Islam to Indigenous Australia. They were so successful, that it is worthwhile to compare their role in spreading Islam with another success story of faith propagation, that of the Jesuit missionaries in China (1580s to 1770s).

We study the convergence of certain subseries of the harmonic series corresponding to increasing ... more We study the convergence of certain subseries of the harmonic series corresponding to increasing sequences of integers whose digits in a certain base are not uniformly distributed. We also discuss the case of irregular sequences, where the frequency distribution of some of the digits does not exist. Examples are given for irregular sequences where the corresponding harmonic subseries is convergent, or divergent, respectively. 2000 Mathematical Subject Classification: 11K36

We present a conjecture about the asymptotic representation of certain series. The conjecture imp... more We present a conjecture about the asymptotic representation of certain series. The conjecture implies the Riemann hypothesis and it would also indicate the simplicity of the non-trivial zeros of the zeta-function 2000 Mathematics Subject Classification: 11M06, 11M26, 11M36, 11M99.