Inverse Methods to Improve Accuracy of Water Content Estimates from Multi-offset GPR

2018 ◽  
Vol 23 (3) ◽  
pp. 349-361
Author(s):  
Andrew D. Parsekian
Keyword(s):  
Water Content ◽  
Careful Analysis ◽  
Subsurface Water ◽  
Geologic Materials ◽  
Improve Accuracy ◽  
The Subject ◽  
Interval Velocities ◽  
Ground Penetrating ◽  
Radar Wave ◽  
The Impact

Ground penetrating radar (GPR) is a powerful hydrogeophysical tool for estimating porosity and water content of geologic materials using radar wave velocities and appropriate petrophysical relations. In substrates with more than one layer of interest, surface-based multi-offset measurements require careful analysis to accurately retrieve physical properties for each layer. Frequently, Dix inversion is used to calculate interval velocities, however the assumptions and limitations of this approach are widely known. In particular for survey geometries and targets encountered with GPR, the assumptions inherent to Dix inversion are readily violated, and therefore inverse modeling is required to avoid velocity error. While the impact on velocity incurred by violating the assumptions of Dix inversion is well understood, the effects on water content estimates have not been widely reported and are therefore the subject of this work. In a subsurface representative of an unsaturated zone overlying an aquifer, error in excess of 50% in water content due to violating the assumptions of Dix inversion is demonstrated. Examples are shown using raytracing inversion to solve for subsurface water content structure that avoids the errors inherent to Dix inversion. These results are intended to underscore the importance of minimizing assumptions and using more correct physics when analyzing multi-offset GPR data, particularly due to the large potential errors that may be encountered if water content estimation is the main objective.

scholarly journals Combined Use of 3D Metric Survey and GPR for the Diagnosis of the Trapezophoros with Two Griffins Attacking a Doe of Ascoli Satriano (Foggia, Italy)

Geosciences ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 307
Author(s):  
Marilena Cozzolino ◽  
Andrea Di Meo ◽  
Vincenzo Gentile ◽  
Paolo Mauriello ◽  
Enza Zullo
Keyword(s):  
Cultural Heritage ◽  
Ground Penetrating Radar ◽  
Visual Inspection ◽  
Careful Analysis ◽  
Preventive Strategies ◽  
State Of Health ◽  
Noninvasive Techniques ◽  
Combined Use ◽  
The Subject ◽  
Ground Penetrating

Protection and conservation are not feasible without a deeper knowledge of the cultural heritage of the subject of intervention. A careful analysis of documentation, a detailed visual inspection of surfaces, and a systematic diagnosis of the inner properties are the basis for planning preventive strategies of restoration. Digital noninvasive techniques represent an advantageous tool with useful outputs to estimate the state of health of cultural heritage in order to minimize the progress of degradation. This paper deals with a 3D metric survey through photogrammetry and ground-penetrating radar (GPR) tests applied to the study of the trapezophoros with two griffins attacking a doe of Ascoli Satriano, a masterpiece of ancient art that needs to be protected. This work provided information on both visible and hidden defects, such as numerous cracks that affect the sculpture.

scholarly journals The role of electrical conductivity in radarwave reflection

2020 ◽  
Author(s):  
Slawek M. Tulaczyk ◽  
Neil T. Foley
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Permittivity ◽  
Specular Reflection ◽  
A Priori ◽  
Normal Incidence ◽  
Radar Reflectivity ◽  
Geologic Materials ◽  
Wide Range ◽  
Radar Wave ◽  
The Impact

Abstract. We have examined a general expression giving the specular reflection coefficient for a radar wave approaching a reflecting interface with normal incidence. The reflecting interface separates two homogeneous media, the properties of which are fully described by three scalar quantities: dielectric permittivity, magnetic permeability, and electrical conductivity. The derived relationship indicates that electrical conductivity should not be neglected a priori in glaciological investigations of subglacial materials, and in GPR studies of saturated sediments and bedrock, even at the high end of typical linear radar frequencies used in such investigations (e.g., 100 MHz). Our own experience in resistivity surveying in Antarctica, combined with a literature review, suggests that a wide range of geologic materials can have electrical conductivity that is high enough to significantly impact the value of radar reflectivity. Furthermore, we have given two examples of prior studies in which inclusion of electrical conductivity in calculation of the radar bed reflectivity may provide an explanation for results that may be considered surprising if the impact of electrical conductivity on radar reflection is neglected. The commonly made assumption that only dielectric permittivity of the two media need to be considered in interpretation of radar reflectivity can lead to erroneous conclusions.

Ground Penetrating Radar for Water Content and Compaction Evaluation: A Laboratory Test on Construction Material

2020 ◽  
Vol 25 (2) ◽  
pp. 169-179
Author(s):  
Hashem Ranjy Roodposhti ◽  
Mohammad Kazem Hafizi ◽  
Mohammad Reza Soleymani Kermani
Keyword(s):  
Dielectric Constant ◽  
Water Content ◽  
Ground Penetrating Radar ◽  
Large Scale ◽  
Construction Material ◽  
Construction Materials ◽  
Dielectric Constants ◽  
Base Layer ◽  
Subsurface Water ◽  
Ground Penetrating

With the aid of ground penetrating radar (GPR), it is possible to evaluate physical properties of a constructed base layer in engineered structures (pavement, land consolidation projects, etc.) non-destructively, quickly, and accurately. High spatial variations of subsurface water content and deficient compaction can lead to unexpected damage and structural instability. In this research, we established a relationship between the dielectric constant, water content, and compaction, whereby, an interactive relationship between these parameters is presented. To achieve this, large-scale laboratory experiments were carried out on construction materials to simulate field conditions. According to USCS, the tested soil type was GW-GM (type E base layer according to Iran's highway specifications code). Furthermore, water content and compaction were changed between 4% -12.9% and 84.7% -94.9%, respectively. The travel-times in each test, including three profiles with more than 210 traces, are measured automatically. Additionally, the calculated dielectric constants were compared with the Topp and Roth equations. R-square and RMS error of the final interactive equation between dielectric constant and water content-compaction were 0.95 and 0.41, respectively. Moreover, the sensitivity analysis of the proposed interactive equation shows that changes in water content of soil have greater impact on dielectric constant than soil compaction changes. The data also indicate the importance of considering the compaction changes of soil to reduce the error in dielectric constant estimation.

Velocity variations and water content estimated from multi‐offset, ground‐penetrating radar

Geophysics ◽  
1996 ◽  
Vol 61 (3) ◽  
pp. 683-695 ◽  
Author(s):  
Robert J. Greaves ◽  
David P. Lesmes ◽  
Jung Mo Lee ◽  
M. Nafi Toksöz
Keyword(s):  
Water Content ◽  
Ground Penetrating Radar ◽  
Velocity Structure ◽  
Signal To Noise Ratio ◽  
Radar Data ◽  
Processing Technique ◽  
Subsurface Water ◽  
Velocity Analysis ◽  
Radar Velocity ◽  
Ground Penetrating

The common midpoint (CMP) processing technique has been shown to be effective in improving the results of ground‐penetrating radar (GPR) profiling. When radar data are collected with the CMP multioffset geometry, stacking increases the signal‐to‐noise ratio of subsurface radar reflections and results in an improved subsurface image. An important aspect of CMP processing is normal‐moveout velocity analysis. Our objectives are to show the effect of multiple velocity analyses on the stacked radar image and particularly, to demonstrate that this velocity information can also be used to determine subsurface water content. Most GPR surveys are very limited in spatial extent and assume that within the survey range, radar velocity structure in the shallow subsurface can be adequately approximated by a single velocity function in data processing. In this study, we show that variation in radar velocity can be quite significant and that the stacked profile improves as the number of velocity analysis locations is increased. Interval velocities can be calculated from the normal moveout velocities derived in the CMP velocity analysis. With some reasonable assumptions about subsurface conditions necessary for radar propagation, interval velocity can be converted to an estimate of volumetric water content. Therefore, by collecting GPR data in the multioffset CMP geometry, not only is the radar profile improved but it also allows for an interpretation of subsurface variation in water content. We show the application of these techniques to multioffset GPR data from the Chalk River test area operated by Atomic Energy of Canada Limited.

Managing Service Quality, Food Quality, Price Fairness and Customer Retention: A Holistic Perspective

2020 ◽  
Vol 2 (1) ◽  
pp. 1-5
Author(s):  
Ammar Ahmed ◽  
Rafat Naseer ◽  
Muhammad Asadullah ◽  
Hadia Khan
Keyword(s):  
Service Quality ◽  
Food Quality ◽  
Service Sector ◽  
Customer Retention ◽  
Price Fairness ◽  
Policy Makers ◽  
Restaurant Management ◽  
The Subject ◽  
Research Propositions ◽  
The Impact

In this competitive environment, organizations strive to satisfy their customer by providing best quality service at affordable and fair prices with a view to enhance their revenues. To achieve the objective of revenue maximization, organizations strive to identify the factors that help them in retaining their customers. Drawing from the signalling theory of marketing, the current study proposes a novel conceptual model representing the impact of service quality with food quality and price fairness on customer retention in restaurant sector of Pakistan. The paper underlines an important arena of knowledge for academicians as well as organizational scientists on the subject. On the basis of literature available on the variables understudy, the present study forwards eight research propositions worthy of urgent scholarly attention. The conceptualized model of the present article can also be viewed significant in unleashing further avenues for the restaurant management entities, policy makers and future researchers in the domain of managing in the service sector businesses.

Solow economy model

2019 ◽  
pp. 150-157
Author(s):  
Oleksandr Synenko ◽  
Kateryna Yarema ◽  
Yuliia Bezsmertna
Keyword(s):  
Economic Growth ◽  
Regression Analysis ◽  
Solow Model ◽  
Economy Model ◽  
Accelerated Depreciation ◽  
Basic Parameters ◽  
The Subject ◽  
Investment Process ◽  
The Impact ◽  
Model Algorithm

The subject of the research is the approach to the possibility of using the Solow model to perform the regression analysis on the example of the Ukrainian economy model. The purpose of writing this article is to investigate the notion of regres- sion analysis, Solow’s economy model, algorithm for performing regression analy- sis on the example of Ukraine’s economy model. This model can be adapted for the economy of enterprises. Methodology. The research methodology is system-struc- tural and comparative analyzes (to study the structure of GDP); monograph (when studying methods of regression analysis on the example of the Ukrainian economy); economic analysis (when assessing the impact of factors on Ukraine’s GDP). The scientific novelty consists the features of the use of the Solow model on the ex- ample of Ukrainian economy are determined. An algorithm for calculating the basic parameters of a model using the Excel application package is disclosed. The main recommendations on the development of the national economy and economic growth through the use of macroeconomic instruments are given. Conclusions. The use of the Solow model enables forecasting and analysis. The results obtained re- vealed the problem of low resource return of capital as a resource, along with the means of macroeconomic regulation of the investment process, using which can improve the situation. A special place in these funds belongs to the accelerated depreciation and interest rate policies.

Assessment of small businesses activities in Ukraine

2019 ◽  
pp. 40-47
Author(s):  
Igor Ponomarenko ◽  
Kateryna Volovnenko
Keyword(s):  
Comparative Analysis ◽  
Statistical Analysis ◽  
Small Business ◽  
Small Businesses ◽  
Government Agencies ◽  
Small Enterprises ◽  
The Subject ◽  
Business Entities ◽  
The Impact ◽  
Micro Enterprises

The subject of the research is a set of approaches to the statistical analysis ofthe activities of small business entities in Ukraine, including micro-enterprises. The purpose of writing this article is to study of the features of functioningof small business entities in Ukraine. Methodology. The research methodology isto use a system-structural and comparative analysis (to study the change in thenumber of small enterprises by major components); monographic (when studyingmethods of statistical analysis of small businesses); economic analysis (when assessing the impact of small business entities on socio-economic phenomena andprocesses in Ukraine). The scientific novelty consists to determine the features ofthe functioning of small businesses in Ukraine in modern conditions. The influenceof the activities of the main socio-economic and political indicators on the activities of small enterprises in recent periods of time has been identified. It has beenestablished that there is flexibility in the development of strategies by small businesses in conditions of significant competition, which makes it possible to quicklyrespond to changing situations in specific markets. Conclusions. The use of acomprehensive statistical analysis of small businesses functioning in Ukraine willallow government agencies to develop a set of measures to optimize the activitiesof these enterprises, which ultimately will positively affect the strengthening oftheir competitiveness and will contribute to the growth of the national economicsystem.

Analysis of Subsurface Water Content with Integrated Techniques.

10.3383/1.1.8 ◽  
2008 ◽  
Vol 1 (1) ◽  
pp. 109-123 ◽  
Author(s):  
G. LEUCCI ◽  
R. CATALDO ◽  
G. DE NUNZIO
Keyword(s):  
Water Content ◽  
Subsurface Water

Le potentiel théâtral chez David Foenkinos. Analyse du roman, du scénario et du film La Délicatesse

2020 ◽  
Vol 65 (2) ◽  
pp. 297-319
Author(s):  
Aluaș Alina
Keyword(s):  
Text Processing ◽  
Careful Analysis ◽  
The Novel ◽  
Work Analysis ◽  
Personal Myth ◽  
The Subject

"The Theatrical Potential in David Foenkinos’ Work. Analysis of the Novel, the Scenario and the Film “La Délicatesse”. Our interest, especially when it comes to the subject of literature, is to show the manner in which the text processing done by the author (script writer/director) brings to light the guidelines of the novelistic text’s semantics, which under careful analysis reveals a kind of personal myth of the novelist. The skewed, syncopated, interrupted writing which disrupts the chronotope serves the needs of the script as well as the director’s selective vision. Unconsciously, the novel seems to follow the structure of the theatrical model. These traits can also be found in the cinematographic structure of the film. Keywords: love, eroticism, delicacy, theatricality, scenario, film. "

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