## Filter Results

Displaying Results 1 - 25 of 86

Publication Year: 2017, Page(s): 1
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• ### [Front cover]

Publication Year: 2017, Page(s): c1
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Publication Year: 2017, Page(s):1 - 7
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• ### Foreword of IWAGPR2017 - the 9th International Workshop on Advanced Ground Penetrating Radar

Publication Year: 2017, Page(s): 1
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• ### 3-D estimation of a foundation pile using polarization-sensitive directional borehole radar

Publication Year: 2017, Page(s):1 - 6
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In this paper, we present a method to estimate the inclination of a foundation pile using polarization-sensitive directional borehole radar. In this method, we estimate the polarization tilt angle of a reflected radar wave incident on a receiving directional antenna. From this we estimate the inclination of the foundation pile. Two experiments using the borehole radar were carried out at a field t... View full abstract»

• ### 3D step frequency GPR Asphalt pavement stripping detection: Case study evaluating filtering approaches

Publication Year: 2017, Page(s):1 - 7
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Stripping between hot mix asphalt layers can cause premature failure of pavements. Knowledge of the lateral location, depth and extent of stripping can affect the timing and type of pavement preservation, maintenance, or rehabilitation. Since subsurface stripping extent is important for maintaining the road network, Minnesota Department of Transportation (MnDOT) uses forensic measures such as cori... View full abstract»

• ### A concept of heterogeneous numerical model of concrete for GPR simulations

Publication Year: 2017, Page(s):1 - 4
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The Ground Penetrating Radar (GPR) method, which is increasingly being used in the non-destructive diagnostics of reinforced concrete structures, often needs more accurate interpretation tools for analysis of experimental data. Recently, there has been growing interest in developing of various numerical models for exhaustive understanding of GPR data. This paper presents the concept of a heterogen... View full abstract»

• ### A lossless earth Green's function representation between any two subsurface points from surface reflection GPR data

Publication Year: 2017, Page(s):1 - 4
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We present a three-dimensional scheme that can be used to compute the electromagnetic impulse response between any two subsurface points from surface reflection data measured at a single surface of a lossless medium. The scheme first computes a virtual vertical radar profile using the Marchenko scheme from which focusing wavefields are computed. With the aid of the Green's functions of the virtual... View full abstract»

• ### A micro-UAV-borne system for radar imaging: A feasibility study

Publication Year: 2017, Page(s):1 - 4
Cited by:  Papers (2)
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Radar mounted onboard micro-UAV is an early stage technology and its potentiality is far from being focused, even if radar sensors having costs compatible with micro-UAV are currently developed. As a contribution to this topic, this paper describes a radar-equipped hexacopter assembled thanks to complementary skills available at IREA and DII. In order to test the operation mode of the system as we... View full abstract»

• ### A numerical model for a GPR device with two receiving antennas

Publication Year: 2017, Page(s):1 - 5
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With the idea of having a GPR device both user-friendly and more accurate than existing systems, the LMDC has proposed a device including one emitting and two receiving antennas for the purpose of non-destructive studies in the context of civil engineering surveys. As a basis of inversion methods to retrieve relevant parameters of a reinforced concrete structure, we propose in this article a 3D nu... View full abstract»

• ### A physical modeling study to analyze the horizontal resolution limits of GPR reflection imaging

Publication Year: 2017, Page(s):1 - 5
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Physical modeling studies at the laboratory scale close the gap between computer simulations and field experiments. In ground-penetrating radar (GPR), such physical models are, for example, useful to study wave propagation phenomena, to evaluate mathematical models, and to develop tools for data analysis, processing, and interpretation. Here, we present an experiment, which has been designed to st... View full abstract»

• ### A simple analysis of dipole antenna radiation above a multilayered medium

Publication Year: 2017, Page(s):1 - 6
Cited by:  Papers (1)
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The paper deals with a simple model of a dipole antenna radiating above a layered medium. The frequency domain formulation is based on the integro-differential equation of the Pocklington type. The influence of the earth-air interface is taken into account via the simplified reflection coefficient arising from the Modified Image Theory (MIT). The Pocklington equation is solved via the Galerkin-Bub... View full abstract»

• ### A Sliced-3D FDTD approach as an alternative to 2D Ground Penetrating Radar modelling

Publication Year: 2017, Page(s):1 - 5
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Ground penetrating radar (GPR) is a powerful tool for characterisation of the subsurface in a range of applications. Finite-difference time-domain (FDTD) forward modelling is often used to gain a more quantitative understanding of the interaction between GPR systems and the region of interest. This can be undertaken in 2D, where simulations fail to model multiple polarisations and require a number... View full abstract»

• ### A variable reflector for measurement of bulk electrical properties of materials using GPR

Publication Year: 2017, Page(s):1 - 4
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A variable reflector controlled by a GPR provides an improved method to measure bulk electrical properties of materials. For sample measurements, the GPR is placed on one side of a sample and the variable reflector on the opposite side. GPR trace data are then acquired with the reflector in on' and off' states. By differencing these measurements, we improve the ability to detect the desired refl... View full abstract»

• ### Accessing a historic wall structure using GPR. The case of Heptapyrgion fortress Thessaloniki Greece

Publication Year: 2017, Page(s):1 - 6
Cited by:  Papers (1)
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In this work we study part of the Northern wall structure of the Heptapyrgion fortress of Thessaloniki (UNESCO monument) that was identified to face moisture and structural problems. Moisture damage is a critical issue in the preservation and integrity of historic walls, thus it is necessary to detect it and to develop restoration plans. Heptapyrgion is one of the most important monuments in Thess... View full abstract»

• ### Accuracy evaluation of traffic-speed coreless GPR techniques in pavement layer thickness estimation

Publication Year: 2017, Page(s):1 - 6
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Ground Penetrating Radar traffic-speed surveys enable the collection of useful data about the condition of the road, in particular giving information about the thickness of pavement materials. Having a reliable and accurate method to “self-calibrate” the GPR data, and thus avoiding the necessity to collect cores, would transform the GPR method into a fully traffic-speed technique that provides a c... View full abstract»

• ### An approximated imaging approach for GPR surveys with antennas far from the interface

Publication Year: 2017, Page(s):1 - 5
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GPR systems for remote surveys, i.e. working with antennas not in contact with the medium under test, are becoming more and more widespread. This kind of systems entails several advantages but complicate the imaging in a not negligible way. Indeed, the wave propagation cannot be properly modeled anymore as occurring into a homogeneous medium and the presence of the air-medium interface has to be t... View full abstract»

• ### An Investigation into the railway ballast grading using GPR and image analysis

Publication Year: 2017, Page(s):1 - 4
Cited by:  Papers (1)
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This study reports on an investigation into the grain size distribution of the railway ballast using ground-penetrating radar (GPR) and image analysis. The proposed approach relies on the hypothesis that the dimension (grading) of the ballast aggregates can influence the back-reflected spectrum received by the use of GPR. This assumption was confirmed by the finite difference time-domain (FDTD) si... View full abstract»

• ### An Ultrawideband Antipodal Vivaldi Antenna for borehole radar application

Publication Year: 2017, Page(s):1 - 5
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An Ultrawideband Antipodal Vivaldi Antenna with compact structure for borehole radar application is reported in this paper. The antenna is embedded in a cylindrical fiber-reinforced plastic (FRP) structure, operating in the frequency range from 600 MHz to more than 4 GHz. A metal reflector is attached to the cylindrical FRP to improve the direction of the antenna especially in low frequency. The s... View full abstract»

• ### Application of Ground penetrating radar for investigating sediment-filled surface karst features (Krk Island, Croatia)

Publication Year: 2017, Page(s):1 - 6
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Ground penetrating radar (GPR) has been widely used in the last decade for investigating various issues in karst environments. Valley-like depressions and other sediment-filled irregular features on karst surface in the south-eastern part of Krk Island, Croatia, were noticed but their genetic mechanism could not be clarified only by geomorphological field observations and the analysis of orthophot... View full abstract»

• ### Automated data extraction from synthetic and real radargrams of district heating pipelines

Publication Year: 2017, Page(s):1 - 5
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The main goal of this paper is to investigate the performance of an algorithm for point extraction from hyperbolic reflections in synthetic and real Ground-Penetrating Radar (GPR) data. The real radargrams that we considered contain hyperbolic reflections due to the presence, in the surveyed area, of district heating pipelines DN250 (250mm inner diameter pipe). These are buried 88 cm deep in a soi... View full abstract»

• ### Characterization of potentially active faults in the southern Upper Rhine Graben using GPR

Publication Year: 2017, Page(s):1 - 6
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The Upper Rhine Graben (URG) is one of the tectonically most active regions in Europe. It is delimited by faults to both sites, which are supposed to be active especially at the eastern side. This area includes a series of critical facilities, e.g. the nuclear power plant Fessenheim, located in direct vicinity of active faults. For risk assessment, the long-term deformation rate within the eastern... View full abstract»

• ### Characterization of seasonal variation of the active layer above permafrost with reverse time migration of GPR profiles near the Qinghai-Tibet Highway

Publication Year: 2017, Page(s):1 - 5
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The permafrost on the Qinghai-Tibet Plateau (QTP) is critically sensitive to temperature changes. The balance of heat transfer between the land and the atmosphere in permafrost regions were disturbed by the construction of man-made infrastructures, such as the Qinghai-Tibet Highway (QTH), the towers of power lines and telecommunications. Obviously, the characteristics of permafrost have been alter... View full abstract»

• ### Combined GPR and ultrasonic tomography measurements for the evaluation of a new concrete pavement

Publication Year: 2017, Page(s):1 - 6
| | PDF (586 KB) | HTML

Ground Penetrating Radar and Ultrasonic Tomography are two nondestructive techniques that are particularly well suited for the inspection of concrete pavements using electromagnetic and ultrasonic sound waves, respectively. In this study, both methods were used for the evaluation of a newly laid concrete pavement. The positions of the dowels in the transverse joints and the thickness of the paveme... View full abstract»

• ### Comparing the measured and modelled response of bespoke antennas using gprMax

Publication Year: 2017, Page(s):1 - 6
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The simulation software gprMax uses the Finite Difference Time Domain (FDTD) method to model propagating electromagnetic (EM) waves primarily for the purpose of ground-penetrating radar (GPR). This open source tool provides a means to investigate the optimal specifications for ground-coupled and air-launched antennas prior to construction. In order for this modelling capability to be fully exploit... View full abstract»