Denis Guilhot

Dr. Denis Guilhot

WorldSensing, C/ Viriat 47, 08014 Barcelona, Spain
orcid

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 September 2019 in Instruments
Verified
Journal Article
Open access
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DGDenis Guilhot
Denis Guilhot
PRPol Ribes-Pleguezuelo
Pol Ribes-Pleguezuelo
The registered history of laser technologies for space application starts with the first laser echoes reflected off the Moon in 1962. Since then, photonic technologies have become very prominent in most technical development. Their presence has also dramatically increased in space applications thanks to the many advantages they present over traditional equivalent devices, such as the immunity against electromagnetic interference, as well as their efficiency and low power consumption. Lasers are one of the key components in most of those applications. In this review, we present an overview of the main technologies involving lasers that are currently deployed in space, before reviewing the requirements for lasers to be reliable in that environment before discussing the advantages and drawbacks of replacing standard technologies by newly developed photonic laser-based devices.

14 July 2021 in Remote Sensing
Verified
Journal Article
Open access
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DGDenis Guilhot
Denis Guilhot
THToni M. del Hoyo
Toni M. del Hoyo
ABAndrea Bartoli
Andrea Bartoli
PRPooja Ramakrishnan
Pooja Ramakrishnan
GLGijs Leemans
Gijs Leemans
GMGintaris Maknavicius
Gintaris Maknavicius
Landslides, often a side effect of mining activities, pose a significant risk to humans and infrastructures such as urban areas, power lines, and dams. Operational ground motion monitoring can help detect the spatial pattern of surface changes and their evolution over time. In this technical note, a commercial, cost-effective method combining a network of geotechnical surface sensors with the InSAR data was reported for the first time to accurately monitor surface displacement. The correlation of both data sets is demonstrated in the Gediminas Castle testbed, where slope failure events were detected. Two specific events were analyzed, and possible causes proposed. The combination of techniques allows one to detect the precursors of the events and characterize the consequences of the failures in different areas in proximity to the castle walls, since the solution allows for the confirmation of long-term drifts and sudden movements in real time. The data from the in situ sensors were also used to refine the satellite data analysis. The results demonstrate that not all events pose a direct threat to the safety of the structure monitored.

1 May 2004 in Optics Letters
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Journal Article
Closed access
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DGDenis Guilhot
Denis Guilhot
GEG. D. Emmerson
G. D. Emmerson
CGC. B. E. Gawith
C. B. E. Gawith
SWS. P. Watts
S. P. Watts
DSD. P. Shepherd
D. P. Shepherd
PSP. G. R. Smith
P. G. R. Smith
A waveguide laser with a neodymium-doped silica core is fabricated on a silicon substrate by a combination of flame hydrolysis deposition, solution doping, and direct UV writing. The neodymium-ion concentration is estimated to be ∼8000 parts in 106. The propagation loss around 1.05 µm is <0.8 dB/cm. Lasing in the range 1048–1056 nm and 1356±1 nm is observed. A slope efficiency of 33% for a high-reflectivity output coupler and a threshold of 4 mW of absorbed power for a 25% output coupler are measured for the F43/2→I411/2 transition.

25 June 2018
Verified
Conference Paper
Open access
XMXavi Masip-Bruin
Xavi Masip-Bruin
EMEva Marín-Tordera
Eva Marín-Tordera
AJAna Juan-Ferrer
Ana Juan-Ferrer
AQAnna Queralt
Anna Queralt
AJAdmela Jukan
Admela Jukan
MCMatic Cankar
Matic Cankar

18 January 2019 in IEEE Transactions on Sustainable Computing
Verified
Journal Article
Closed access
PNPanagiota Nikolaou
Panagiota Nikolaou
YSYiannakis Sazeides
Yiannakis Sazeides
ALAlejandro Lampropulos
Alejandro Lampropulos
DGDenis Guilhot
Denis Guilhot
ABAndrea Bartoli
Andrea Bartoli
GKGeorgios Karakonstantis
Georgios Karakonstantis
We are witnessing an explosive growth in the number of Internet-connected devices and the emergence of several new classes of Internet of Things (IoT) applications that require rapid processing of an abundance of data. To overcome the resulting need for more network bandwidth and low network latency, a new paradigm has emerged that promotes the offering of Cloud services at the Edge, closer to users. However, the Edge is a highly constrained environment with limited power budget for servers per Edge installation which, in turn, limits the number of Internet-connected devices, such as sensors, that an installation can service. Consequently, the limited number of sensors leads to a reduction in the area coverage provided by them and puts in question the effectiveness for deploying IoT applications at the Edge. In this paper, we investigate the benefits of running an emerging security focused IoT application, (jamming detection), at the Edge vs. the Cloud by developing a Total Cost of Ownership (TCO) model, which considers the application's requirements as well as the Edge's constraints. For the first time, we build such a model based on realistic performance and energy-efficiency measurements obtained from commodity 64-bit ARM based micro-servers that are excellent candidates for supporting Cloud services at the Edge. Such servers represent the type of devices that can provide the right balance between power and performance, without requiring any complicate cooling and power supply infrastructure, which will not be available at the de-centralized deployments. Aiming at improving the energy efficiency, we exploit the pessimistic design margins adopted conventionally in such devices and investigate their operation under lower than nominal supply voltage and memory refresh-rate. Our results show that the jamming detection application deployed at an Edge environment is superior to a Cloud based solution by up to 2.13 times in terms of TCO. Moreover, when servers operate below nominal conditions, we can achieve up to 9 percent power savings which enables in several situations 100 percent gains in the TCO/area-coverage metric, i.e double area can be served with the same TCO.

19 April 2019 in Instruments
Verified
Journal Article
Open access
PDF file
PRPol Ribes-Pleguezuelo
Pol Ribes-Pleguezuelo
DGDenis Guilhot
Denis Guilhot
MBMarta Gilaberte Basset
Marta Gilaberte Basset
EBErik Beckert
Erik Beckert
RERamona Eberhardt
Ramona Eberhardt
ATAndreas Tünnermann
Andreas Tünnermann
1960 is the birth year of both the laser and the Mars exploration missions. Eleven years passed before the first successful landing on Mars, and another six before the first rover could explore the planet’s surface. In 2011, both technologies were reunited with the first laser landing on Mars as part of the ChemCam instrument, integrated inside the Curiosity Rover. In 2020, two more rovers with integrated lasers are expected to land on Mars: one through the National Aeronautics and Space Administration (NASA) Mars 2020 mission and another through the European Space Agency (ESA) ExoMars mission. The ExoMars mission laser is one of the components of the Raman Spectrometer instrument, which the Aerospace Technology National Institute of Spain (INTA) is responsible for. It uses as its excitation source a laser designed by Monocrom and manufactured in collaboration with the Fraunhofer Institute for Applied Optics and Precision Engineering (IOF). In this paper, we present for the first time the final flight module laser that has been installed in the rover’s onboard laboratory and validated to be shipped to Mars in 2020. Particular emphasis is given to mechanical considerations and assembly procedures, as the ExoMars laser assembly has required soldering techniques in contrast to the standard adhesive technologies used for most laser assembly processes in order to fulfill the environmental and optical requirements of the mission.