Events September 2023 OES Beacon

The Student Poster Competition at OCEANS 2023 Limerick

Dr. Shyam Madhusudhana, OES Student Poster Competition Chair
Photo credits: Nicholas Chotiros, Caoimhe Corrigan, and Manu Ignatius

…and so was the awards ceremony.
Poster sessions were well-attended on all days…

Col. Normal Miller conceived and brought to life the esteemed Student Poster Competition (SPC) during the 1989 Seattle OCEANS conference. Since its inception, the SPC has remained a prominent highlight of OCEANS conferences worldwide. Welcoming undergraduate and graduate students from esteemed institutions across the globe, the SPC stands tall as a flagship event of the esteemed MTS/OES OCEANS conferences. Each year, we witness a plethora of aspiring talents vying for a spot in the Competition. Through a stringent two-stage review process of their submitted abstracts, we handpick a select group of 15–20 students who demonstrate exceptional promise. These chosen candidates’ conference registration fees are waived, and they also receive financial support to aid their travel and accommodation expenses.

The success of the SPC would not be possible without the generous support of our sponsoring societies — OES and MTS. We extend our heartfelt gratitude to the Office of Naval Research—Global (ONR-G) for their unwavering financial backing, which has allowed us to continue nurturing the next generation of brilliant minds. The Schmidt Ocean Institute has generously continued their contribution of prize money for this edition of the SPC.

The Limerick OCEANS SPC received a whopping 83 abstracts. The Local Organizing Committee’s (LOC) SPC Chair, Petar Trslic, and Coordination Chair, Isela Ibrahimovic, bravely took on the gargantuan task of running the SPC successfully. Out of the submissions received, 14 abstracts were shortlisted for the final program. Of these, one participant could not attend due to visa issues. The poster sessions were very well attended, and the students seemed to have enjoyed their time at the conference. We had a panel of 7 judges who generously offered their time, speaking to each participant and scoring their posters. We are grateful for their support. The awards ceremony was held prior to the exhibitors’ luncheon on the final day of the conference. Participation certificates and winning prizes were handed out by the sponsoring societies’ Presidents — Christopher Whitt (OES) and Justin Manley (MTS).

The list of participants (including the prize winners), together with their affiliation, poster title and an abstract of their poster, are given below.

First prize (Norman Miller Award) (Certificate and $ 3000)

Amelia Ritger, University of California, Santa Barbara, USA

Developing Low-Cost, Simplified, and Open-Source Durafet-based pH Instrument Electronics

Abstract— Ocean acidification monitoring efforts are a crucial component of tracking the impacts of climate change in marine ecosystems. However, the high instrument cost presents a major barrier to the production of scientific knowledge and has resulted in a highly fragmented understanding of the global progression of acidification. Our project built upon an existing nearshore marine pH sensor design which utilizes a Durafet pH electrode. Our goal was to lower barriers to access by significantly lowering the cost of, and improving approachability to, the design and use of pH sensor electronics. We have created a more compact design using open-source components based on the popular and easy-to-use Arduino platform that eliminates over $900 from the cost of the sensor electronics. We demonstrate with lab and field testing that switching to Arduino-based sensor electronics maintains high data fidelity. Our design supports open science by allowing more individuals and research groups to engage in high-quality oceanographic research.

Second prize (Certificate and $ 2000)

Jared McFadden, Florida Atlantic University, USA

Design and Failure Analysis of Multi-Component Mooring Lines with Non-Linear Polymer Springs for Floating Offshore Wind Turbines

Abstract— Floating offshore wind turbines (FOWT) stationed in transition depths (50-80 m) offer easier access for installation and maintenance and broaden the spectrum of operational locations when compared to fixed bottom or deep-water structures. The fatigue performance and abrasion resistance of polyester makes it the preferred choice for taut leg systems because this mooring method uses the elastic characteristics of the rope to provide station keeping effects. Adding non-linear polymer springs to this mooring configuration helps reduce peak loads, platform surge, and increase fatigue life. This research studied the effects of changing line pretension, spring safe working load (force exerted at 50% elongation), and spring response curve on peak loads and platform surge first by modeling the system in OrcaFlex at yearly average and 50-year storm environmental conditions. The maximum tension load from the optimized mooring assembly was applied to a modeled section of the 8-strand multiplait rope in ANSYS Workbench to study deformation, stress, and fatigue life. The OrcaFlex simulations showed that a mooring line pretensioned at 1250 kN with a 4500 kN safe working load degressive spring was the optimal assembly. The peak tension of 3717 kN was applied to the section model in ANSYS and yielded a deformation of 0.268 m and maximum stress of 3.20e8 Pa at the inner radius of the weaving section of the rope. This research will

continue by analyzing the fatigue life performance of the rope section at the 50-year storm data to predict operational lifetime and at average conditions to validate the design with industry standards.

Third prize (Certificate and $ 1000)

Patrick McGuire, Woods Hole Oceanographic Institution, USA

TideRider: A Low-Cost Coastal Profiling Float

Abstract— Coastal ecosystem stressors such as hypoxia, marine heatwaves and harmful algal blooms require new technologies to properly monitor and predict. Instrumented buoys, gliders, profiling floats, and shore stations are all applicable to the coastal domain, but all face certain limitations that prevent deployment in large numbers. We designed TideRider, easy to build, $1600 profiling floats intended primarily for coastal water quality monitoring.

TideRiders profile between the surface and seafloor, resting on the seafloor between profiles. By timing ascents and descents, it is possible to opportunistically harness ambient currents to move the devices in a controlled way, e.g., toward a waypoint, or to hold station as a “virtual mooring.” This capability was demonstrated in a series of field tests in summer 2022.

Gerard Batet, Universitat Politecnica de Catalunya, Spain

Engineering a testbed for bidirectional acoustic tag development

Abstract— Marine protected areas (MPAs) have been implemented to mitigate the effects of climate change and overfishing on various marine ecosystems. Nonetheless, these areas need monitoring to ensure their actual utility. Tools like acoustic tags are used to study the animals’ behavioural patterns and obtain valuable information to improve MPAs. Recently, new

architectures have been proposed to overcome the inherent limitations of off-the-shelf tags, for example, by implementing bidirectional communication capabilities with the newly developed open protocol from European Tracking Network. In this paper, the testbed topology and methodology used to develop these bidirectional acoustic tags are discussed alongside the laboratory results achieved.

Valerio Franchi, University of Girona, Spain

Distortion Correction of AUV-acquired Side-Scan Sonar Data

Abstract— Side scan sonars (SSS) are types of sonars that produce representations of the sea-bed by emitting and receiving acoustic fan-shaped pulses perpendicularly to the motion of the sensor in the water. Generally, SSS are deployed from a towed vehicle pulled from a boat at high speed to avoid oscillatory motions and thus achieve a clean and consistent sea-bed scan. Our approach targets the use of SSSs on small AUVs with limited computing power, and travelling at slow speeds, where the waterfall is directly used for real-time classfication. Due to the increased oscillatory motion, the SSS waterfall tends to have significant distortion, that will preclude the classifier from obtaining correct results. The algorithm described in this paper performs a geometric correction of the sonar scanlines by taking into account the AUV’s change in height, yaw and pitch to calculate correctly their positions on the seabed. The data is mapped into a 2D grid using the scanline intensities to form a mosaic, and the missing mosaic pixels are interpolated using a Gaussian-based kernel. The waterfall is recreated by considering a modified AUV trajectory with smooth changes in heading and a null pitch. The results show a significant improvement in the waterfall output, removing unwanted distortions and displaying the seabed structures with higher geometric consistency. In addition, the concentration of the ping data on the waterfall is constant all around, compared to the varying contribution density in the original one.

Donghyun Kim, Korea Advanced Institute of Science and Technology, Republic of Korea

Mission planning for collaborative operation of autonomous marine systems

Abstract— Autonomous systems consisting of multiple surface and underwater vehicles are capable of performing long-term, high level tasks through cooperation. However, achieving reliable autonomy under substantial uncertaies and environmental changes requires a system that can recognize the situation and make high-level decisions. This study presents a mission planner developed using Planning Domain Definition Language (PDDL) with a replanning structure that incorporates three methods to enhance both optimality and robustness. The planner employs three methods to achieve this: the greedy iterative method improves the planner’s optimality, the model adaptive reduces the gap between the environment and the model to increase operational performance, and the reserved enhances mission success rates by allowing the planner to adapt to changes in the environment. We demonstrate that the proposed mission planner can provide an efficient and stable plan to complete a mission.

Xi Lu, University of British Columbia, Canada

Transfer Learning of Image Classification Networks in Application to Dolphin Whistle Detection

Abstract— Dolphin whistle detection is an important and multi-purpose but time-consuming task. The ability to automate and streamline this process can be invaluable for future research in marine studies and other fields that aim to utilise these signals. When dealing with underwater acoustics, a large obstacle to overcome is the abundance of noise and interfering sounds, natural and anthropogenic alike. In this paper, we apply successful image classification networks to two separate datasets containing dolphin whistles with the goal of determining an effective method to conduct automated detection with minimal interference from a manual operator regardless of environment. We further investigate the impacts of shrinking the dataset size and performing parameter freezing on the networks at hand. Networks are assessed by their detection accuracy and achieve performances comparable to those in existing works, the best being 96.7%, thus proving the effectiveness of these pre-trained image classification models.

António Oliveira, Faculdade de Engenharia da Universidade do Porto, Portugal

Feature Extraction Towards Underwater SLAM using Imaging Sonar

Abstract— Blob features are particularly common in acoustic imagery, as isolated objects (e.g., moorings, mines, rocks) appear as blobs in the acquired images. This work focuses the application of the SIFT, SURF, KAZE and U-SURF feature extraction algorithms for blob feature tracking towards Simultaneous Localization and Mapping applications. We introduce a modified feature extraction and matching pipeline intended to improve feature detection and matching precision, tackling performance deterioration caused by the differences between optical and acoustic imagery. Experimental evaluation was undertaken resorting to datasets collected from a water tank structure.

Patryk Olszewski, Aalborg University Esbjerg, Denmark

On Cathodic Protection Monitoring and Inspection of Seabed Pipelines

Abstract— Cathodic Protection (CP), alongside coating, is the primary prevention technique against corrosion of seabed pipelines. This system requires a regular monitoring that ensures its proper functioning. This study presents a review of existing, widely used methods for CP surveillance. Additionally, an optimal and robust surveillance method, based on testing stations using Wireless Sensor Network (WSN) mediated by an Autonomous Underwater Vehicle (AUV), is described. The description involves powering of the test station, its communication with the AUV as well as the navigation requirements for pipe following of the vehicle.

Jingyu Song, University of Michigan, USA

Uncertainty-Aware Acoustic Localization and Mapping for Underwater Robots

Abstract— For underwater vehicles, robotic applications have the added difficulty of operating in highly unstructured and dynamic environments. Environmental effects impact not only the dynamics and controls of the robot but also the perception and sensing modalities. Acoustic sensors, which inherently use mechanically vibrated signals for measuring range or velocity, are

particularly prone to the effects that such dynamic environments induce. This paper presents an uncertainty-aware localization and mapping framework that accounts for induced disturbances in acoustic sensing modalities for underwater robots operating near the surface in dynamic wave conditions. For the state estimation task, the uncertainty is accounted for as the added noise caused by the environmental disturbance. The mapping method uses an adaptive kernel-based method to propagate measurement and pose uncertainty into an occupancy map. Experiments are carried out in a wave tank environment to perform qualitative and quantitative evaluations of the proposed method. More details about this project can be found at

Simone Tani, Università di Pisa, Italy

Comparison of Monocular and Stereo Vision approaches for Structure Inspection using Autonomous Underwater Vehicles

Abstract— Periodical inspections are a fundamental operation to monitor the status of underwater structures and to assess their need for proper maintenance or repair interventions. Autonomous Underwater Vehicles (AUVs) could represent a viable option to carry out underwater inspection tasks, potentially bringing benefits in terms of safety for human operators and quality of the collected data. Aiming at developing a fully autonomous vision-based inspection strategy, this paper proposes a comparative analysis between monocular and stereo vision approaches for estimating the lateral velocity of an AUV and its orientation with respect to a target surface. The proposed analysis is performed by exploiting a dataset of real underwater images, collected during at-sea experiments in which the Zeno AUV was remotely driven to carry out a pier inspection. Specifically, the performance of the two solutions in terms of estimation of the robot lateral velocity is assessed by considering doppler velocity log measurements as benchmark. Instead, the accuracy of the estimation of the vehicle orientation with respect to the target is evaluated by taking into account both geographical information of the pier and AUV attitude observations. The comparison suggests that stereo vision provides better performance for estimating the relative orientation between the AUV and the target; on the contrary, the monocular approach produces more reliable lateral velocity estimates. The results obtained prove the suitability of the two vision-based strategies for inspection applications in a real underwater scenario, thus suggesting a possible implementation onboard the reference vehicle.

Edoardo Topini, University of Florence, Italy

The RUVIFIST project: preliminary experimental results with a Reconfigurable Underwater Vehicle for Inspection, Free Floating Intervention, and Survey Tasks

Abstract— The development of vehicles incorporating both the Autonomous Underwater Vehicle (AUV) and the Remotely Operated Vehicles (ROV) intervention functionalities can be considered one of the most investigated tasks of the underwater industry and the scientific community. A feasible solution can be the development of Autonomous Underwater Reconfigurable Vehicles (AURVs), i.e. vehicles that can change their current configuration depending on the demanded task. Driven by these considerations, an innovative AURV has been developed by the Department of Industrial Engineering of the University of Florence (DIEF), Italy, capable of efficiently reconfiguring its shape according to the task at hand. In particular, the RUVIFIST (Reconfigurable Underwater Vehicle for Inspection, Free-floating Intervention and Survey Tasks) vehicle has been provided with two extreme configurations: a slender (“survey”) configuration for long navigation tasks and a stocky (“hovering”) configuration designed for challenging goals as intervention operations. Consequently, this work presents the results obtained during several experimental campaigns conducted to accurately test the vehicle reconfigurable system and how the standard Guidance, Navigation and Control (GNC) strategies must be adapted for AURVs.

Laurent Verrier, Exail, France

Simulations and Experiments with a 1D Interferometric Doppler Velocity Sonar

Abstract— The Interferometric DVL (InDVL) is a new instrument designed to be free from acoustic bias. The InDVL combines pulse-to-pulse phase comparison, used by all wideband Doppler sonars, with element-to-element phase comparison generally used for direction finding. The most general InDVL receiver array design consists of a 3D ultrashort baseline, with four hydrophones in a tetrahedral configuration allowing the synthesis of three orthogonal baselines. In this paper we study the performance of a much simpler system consisting of a single baseline and present both Monte Carlo simulations and preliminary experimental results using a COTS sonar of opportunity, which is a dual Mills cross scientific echo sounder used for fishery research and obstacle avoidance.