Iraklis Giannakis

Iraklis Giannakis
University of Aberdeen | ABDN · School of Geosciences

Ph.D, M.Sc, B.S

About

74
Publications
15,712
Reads
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1,315
Citations
Citations since 2016
60 Research Items
1293 Citations
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
Additional affiliations
September 2018 - present
University of West London
Position
  • Module leadier "Calculus II", "Numerical Methods"
March 2018 - present
University of West London
Position
  • Research Associate
February 2017 - February 2018
The University of Edinburgh
Position
  • PostDoc Position
Education
March 2011 - March 2015
The University of Edinburgh
Field of study
  • Geophysics
September 2009 - September 2011
Aristotle University of Thessaloniki
Field of study
  • Geophysics
September 2003 - September 2009
Aristotle University of Thessaloniki
Field of study
  • School of Geology

Publications

Publications (74)
Article
A three-dimensional (3-D) finite-difference time-domain (FDTD) algorithm is used in order to simulate ground penetrating radar (GPR) for landmine detection. Two bowtie GPR transducers are chosen for the simulations and two widely employed antipersonnel (AP) landmines, namely PMA-1 and PMN are used. The validity of the modeled antennas and landmines...
Article
Finite-difference time-domain forward modeling of ground-penetrating radar (GPR) is becoming regularly used in model-based interpretation methods, such as full-waveform inversion (FWI) and machine learning schemes. Oversimplifications in such forward models can compromise the accuracy and realism with which real GPR responses can be simulated, whic...
Article
The simulation, or forward modeling, of ground penetrating radar (GPR) is becoming a more frequently used approach to facilitate the interpretation of complex real GPR data, and as an essential component of full-waveform inversion (FWI). However, general full-wave 3-D electromagnetic (EM) solvers, such as the ones based on the finite-difference tim...
Article
Full-waveform inversion (FWI) is considered one of the most promising interpretation tools for hydrogeological applications using ground-penetrating radar. However, FWI has had limited practical uptake for several reasons: large computational requirements, an inability to reconstruct loss mechanisms of soil, and the need for a good initial starting...
Article
Full-text available
Plain Language Summary The landing site of Chang’E‐4 is at the Von Kármán (VK) crater at the South Pole‐Aitken (SPA) basin. The SPA basin is the oldest and biggest basin on the Moon created at the early stages of its evolution by an impact that is, believed to have penetrated the lunar crust and uplifted materials from the top mantle. Understanding...
Article
Hyperbola fitting is a mainstream interpretation technique used in ground-penetrating radar (GPR) due to its simplicity and relatively low computational requirements. Conventional hyperbola fitting is based on the assumption that the investigated medium is a homogeneous half-space, and that the target is an ideal reflector with zero radius. However...
Conference Paper
There is a need to accurately simulate materials with complex electromagnetic properties when modelling Ground Penetrating Radar (GPR), as many objects encountered with GPR contain water, e.g. soils, curing concrete, and water-filled pipes. One of widely-used open-source software that simulates electromagnetic wave propagation is gprMax. It uses Ye...
Preprint
Full-text available
General full-wave electromagnetic solvers, such as those utilizing the finite-difference time-domain (FDTD) method, are computationally demanding for simulating practical GPR problems. We explore the performance of a near-real-time, forward modeling approach for GPR that is based on a machine learning (ML) architecture. To ease the process, we have...
Article
This paper proposes a nondestructive evaluation method based on deep learning using combined ground‐penetrating radar (GPR) and electromagnetic induction (EMI) data for autonomic and accurate estimation of the cover thickness and diameter of reinforcement bars. A real‐time object detection algorithm—You Only Look Once–version 3 (YOLO v3)—is adopted...
Article
Internal decays in trees can rapidly escalate into a full decomposition of the inner structural layer, i.e., the "heartwood" layer, due to the action of aggressive diseases and fungal infections. This process leads to the formation of big cavities and hollows, which remain surrounded by the sapwood layer only. Estimating the thickness of the sapwoo...
Preprint
Full-text available
There is a need to accurately simulate materials with complex electromagnetic properties when modelling Ground Penetrating Radar (GPR), as many objects encountered with GPR contain water, e.g. soils, curing concrete, and water-filled pipes. One of widely-used open-source software that simulates electromagnetic wave propagation is gprMax. It uses Ye...
Article
Full-text available
Estimating the permittivity of heterogeneous mixtures based on the permittivity of their components is of high importance with many applications in ground penetrating radar (GPR) and in electrodynamics-based sensing in general. Complex Refractive Index Model (CRIM) is the most mainstream approach for estimating the bulk permittivity of heterogeneou...
Article
Full-text available
The preservation of natural assets is nowadays an essential commitment. In this regard, root systems are endangered by fungal diseases which can undermine the health and stability of trees. Within this framework, ground penetrating radar (GPR) is emerging as a reliable non-destructive method for root investigation. A coherent GPR-based root-detecti...
Article
In oil drilling, mud filtrate penetrates into porous formations and alters the compositions and properties of the pore fluids. This disturbs the logging signals and brings errors to reservoir evaluation. Drilling and logging engineers therefore deem mud invasion as undesired, and attempt to eliminate its impacts. However, the mud-contaminated forma...
Article
Modern socioeconomic factors such as global timber trade and international travelling have contributed to the rapid increase of Emerging Infectious Diseases (EIDs) of trees with devastating effects to the European forests and woodlands. To that extent, numerous non-destructive methodologies have been suggested as diagnostic tools in order to effect...
Conference Paper
Full-text available
Street trees are widely recognised to be an essential asset for the urban environment, as they bring several environmental, social and economic benefits [1]. However, the conflicting coexistence of tree root systems with the built environment, and especially with road infrastructures, is often cause of extensive damage, such as the uplifting and cr...
Conference Paper
Full-text available
Non-destructive testing (NDT) for health monitoring of trees is a suitable candidate for detecting signs of early decay [1]. Recent developments [2,3,4] have highlighted that ground-penetrating radar (GPR) has the potential to provide with a robust and accurate detection tool with minimum computational and operational requirements in the field. In...
Conference Paper
Full-text available
The danger related to the structural stability of hollowed trees is a matter of wide discussion among the scientific community. Hollow cores in trees can extend to more than 50% of the total diameter [1] and, while the presence of a hollow tree might appear dramatic in terms of public safety, it is not always a cause of concern. It is known that ho...
Article
The importance of street trees in the urban environment is widely recognised. Nevertheless, the absence of proper urban planning, combined with lack of resources and methodologies for road maintenance, have made the interaction between trees and the urban environment as a priority task to pursue. The uncontrolled development of tree roots can cause...
Article
Full-text available
In this paper, we have presented a methodology combining ground penetrating radar (GPR) and a low-cost GPS receiver for three-dimensional detection of tree roots. This research aims to provide an effective and affordable testing tool to assess the root system of a number of trees. For this purpose, a low-cost GPS receiver was used, which recorded t...
Article
Ground penetrating radar (GPR) is a well-established tool for detecting and locating reinforcing bars (rebars) in concrete structures. However, using GPR to quantify the diameter of rebars is a challenging problem that current processing approaches fail to tackle. To that extent, we have developed a novel machine learning framework that can estimat...
Article
Ash dieback, acute oak decline (AOD) and Xylella Fastidiosa are Emerging Infectious Diseases (EIDs) that have spread rapidly in European forests during the last decade. Quarantine measurements have mostly failed to repress the outbreaks and millions of trees have already been infected. Identifying infected trees in a non-destructive manner is of hi...
Conference Paper
The importance of street trees in the urban environment is widely recognised. They provide several environmental, economic and social benefits, increasing the liveability of cities and improving people health. Nevertheless, the absence of proper urban planning, combined with the deficiency of resources and methodologies for road maintenance, have l...
Conference Paper
Estimating the root density of mature trees is of high importance as the root system is a robust indicator of both the health status and the structural integrity of a tree. With this in mind, a multi-stage data processing scheme is proposed using Ground Penetrating Radar (GPR) to achieve an effective estimation of the root density of trees. The pro...
Conference Paper
A variety of tree species, such as ash and oak trees, are nowadays under serious threat in the United Kingdom and European territories as a result of the action of aggressive fungal diseases. To this effect, Ground Penetrating Radar (GPR) is an effective geophysical tool capable of collecting information on the internal structure of trees. Neverthe...
Conference Paper
Full-text available
Invasive fungi diseases are considered one the biggest threats for the ash and oak forests in United Kingdom. To that extend, Ground Penetrating Radar (GPR) can provide a powerful diagnostic tool for assessing the health status of tree trunks based on their internal dielectric distribution. GPR acquisitions in tree-trunks is a unique problem that c...
Article
Full-text available
Aggressive fungal and insect attacks have reached an alarming level, threatening a variety of tree species, such as ash and oak trees, in the United Kingdom and beyond. In this context, Ground Penetrating Radar (GPR) has proven to be an effective non-invasive tool, capable of generating information about the inner structure of tree trunks in terms...
Conference Paper
Full-text available
Emerging infectious diseases (EIDs) of trees have rapidly increase during the last 20 years due to modern socio-economic factors such as global timber trade and international travelling [1], [2]. Currently, the most dominant EIDs affecting the European forests are the ash dieback [1], the Xylella Fastidiosa [3] and the acute oak decline (AOD) [4]....
Article
Ground penetrating radar (GPR) is traditionally applied to smooth surfaces in which the assumption of half-space is an adequate approximation that does not deviate much from reality. Nonetheless, using GPR for internal structure characterization of tree trunks requires measurements on an irregularly shaped closed curve. A typical hyperbola fitting...
Article
Self‐potential (SP) is a passive geophysical method that can be applied in a straightforward manner with minimum requirements in the field. Nonetheless, interpretation of SP data is particularly challenging due to the inherited non‐uniqueness present in all potential methods. Incorporating information regarding the target of interest can facilitate...
Conference Paper
Full-text available
Management and conservation of natural heritage are becoming increasingly important as health of ancient trees is threatened by the presence of unknown and aggressive pathogens [1]. In this regard, root systems are threatened by fungal infections inducing rotting of roots and eventually leading to death of trees. These infections may easily spread...
Conference Paper
Full-text available
Evaluating and assessing the internal structure of tree-trunks is of great importance both for industrial as well as environmental purposes [1]. Non-destructive geophysical techniques with minimum intrusion can assist on tree monitoring by providing fast and cheap tools for assessing the internal structure of tree trunks. In the current work we eva...
Article
Full-text available
The Finite-Difference Time-Domain (FDTD) method is a popular numerical modelling technique in computational electromagnetics. The volumetric nature of the FDTD technique means simulations often require extensive computational resources (both processing time and memory). The simulation of Ground Penetrating Radar (GPR) is one such challenge, where t...
Conference Paper
This study presents recent advances achieved in the use of ground penetrating radar (GPR) for the health monitoring of tree root systems. The main objectives of the research were to provide an effective and high-resolution mapping of the root systems belonging to different species of matured trees, as well as to investigate areas of roots interconn...
Article
Full-text available
gprMax is open source software that simulates electromagnetic wave propagation, using the Finite-Difference Time-Domain (FDTD) method, for the numerical modelling of Ground Penetrating Radar (GPR). gprMax was originally developed in 1996 when numerical modelling using the FDTD method and, in general, the numerical modelling of GPR were in their inf...
Thesis
Full-text available
Ground-Penetrating Radar (GPR) is a popular non-destructive geophysical technique with a wide range of diverse applications. Civil engineering, hydrogeophysics, forensic, glacier geology, human detection and borehole geology are some of the fields in which GPR has been applied with successful or promising results. One of the most mainstream applica...
Article
A regression model is developed in order to estimate in real time the signal-to-clutter ratio (SCR) for landmine detection using ground-penetrating radar. Artificial neural networks are employed in order to express SCR with respect to the soil's properties, the depth of the target, and the central frequency of the pulse. The SCR is synthetically ev...
Conference Paper
Full-text available
Ground penetrating radar (GPR) is a very common technique for exploring the subsurface. Lately, a different use of GPR has emerged from the need to search for and rescue victims in collapsed buildings and/or rock falls. Since the employment of ultra-wideband (UWB) radar devices is still a very new technique for rescue teams, many technology changes...
Poster
Full-text available
A regression model using ANN is developed in or- der to model and predict (in real time) SCR for a wide range of diverse scenarios. Resolving the pre- sent feature space requires an equally distributed and adequately large training set. The latter is syn- thetically generated using FDTD. Fractal correlated noise is chosen for modelling both the soi...
Conference Paper
Full-text available
Understanding how energy is transmitted and received by Ground Penetrating Radar antennas is crucial to many areas of the industry: antenna design, data processing and inversion algorithms, usage of antennas in GPR surveys, and interpretation of GPR responses. The radiation characteristics of antennas are usually investigated by studying the radiat...
Conference Paper
A numerical modelling case study is presented aim- ing to investigate aspects of the applicability of artificial neural networks (ANN) to the problem of landmine detection using ground penetrating radar (GPR). An essential requirement of ANN and machine learning in general, is a coherent training set. A good training set should include data from as...
Conference Paper
Full-text available
gprMax is a freely-available set of electromagnetic wave simulation tools based on the Finite-Difference Time- Domain (FDTD) numerical method. gprMax was originally written in the mid-1990s and has primarily been used to simulate Ground Penetrating Radar (GPR). Current computing resources offer the opportunity to build detailed and complex FDTD mod...
Article
A performance enhancing modification to the convolutional perfectly matched layer (CPML) technique for implementing the complex frequency shifted perfectly matched layer (CFS-PML) absorbing boundary condition is presented. By adopting this modification an apparent discrepancy in the time synchronisation between the CPML and the main FDTD algorithm...
Conference Paper
Full-text available
A modelling framework for realistic ground penetrating radar simulation in complex environments is presented. This approach incorporates detailed models of ground penetrating radar transducers as well as realistic descriptions of the underlying media and targets. The simulation of air-coupled horn antennas is presented and their performance is eval...
Conference Paper
A finite-difference time-domain (FDTD) algorithm is used to model and study the performance of ground penetrating radar (GPR) for anti-personnel (AP) landmine detection. A novel algorithm is proposed which creates the geometry of the vegetation for both grass and roots. Soil's inhomogeneities as well as the rough surface are simulated using fractal...
Data
Full-text available
Air coupled antennas like horn antennas have been extensively used for pavement evaluation using Ground Penetrating Radar (GPR). The main reasons for that are : -Low spatial resolution -Capable to detect thin layers -Safely operates in highway speeds because it doesn't need to be close to the ground -Easy to manufacture A high frequency 2.6 GH...
Article
Full-text available
Two novel methods for implementing recursively the convolution between the electric field and a time dependent electric susceptibility function in the finite-difference time domain (FDTD) method are presented. Both resulting algorithms are straightforward to implement and employ an inclusive susceptibility function which holds as special cases the...
Conference Paper
In this work a new geophysical methodology is presented which is able to detect any displacements of buried electrodes that are permanently installed in boreholes. These displacements can seriously affect the quality of the measurements and the subsequent resistivity inversion image. The exact knowledge of the electrode displacements will either he...