Article
Engineering, Marine
Yang Song, Xudong Xie, Yanhui Wang, Shaoqiong Yang, Wei Ma, Peng Wang
Summary: The paper proposes an energy consumption prediction model based on LSSVM and PSO algorithms, showing that the model with radial basis kernel function outperforms others. Moreover, with a large enough training sample size, the performance of the LSSVM-PSO model can be significantly improved.
Article
Automation & Control Systems
Wentao Zhao, Jiancheng Yu, Fumin Zhang, Yan Huang, Aiqun Zhang
Summary: A new heading angle control method is proposed for underwater gliders to follow a straight line sampling path relative to a dynamically moving mesoscale eddy, utilizing constant velocity and constant acceleration kinematic models for eddy center movements. Model parameters are identified from historical data, and a Kalman filter is developed for real-time estimation and prediction of eddy center movement. Comparative analysis based on historical data shows that the constant velocity model is preferred for glider heading control during eddy movement prediction, with simulation and field experiments confirming autonomous sampling path tracking capabilities with acceptable levels of tracking error.
CONTROL ENGINEERING PRACTICE
(2021)
Article
Automation & Control Systems
Lei Wan, Dongliang Zhang, Yanchao Sun, Hongde Qin, Yu Cao, Guofang Chen
Summary: This paper presents a fast fixed-time vertical plane motion controller for autonomous underwater gliders (AUGs) operating in shallow water. Various influencing factors are taken into account and corresponding solutions are proposed. Simulation results demonstrate the rapidity and effectiveness of the designed control method.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2022)
Article
Public, Environmental & Occupational Health
Xi Chen, Neil Bose, Mario Brito, Faisal Khan, Ting Zou
Summary: Autonomous underwater gliders (AUGs) are effective platforms for oceanic research and environmental monitoring. However, there is a risk of vehicle loss in complex underwater environments. This study proposes a copula-based approach for evaluating the risk of AUG loss, considering both dynamic environments and potential functional failures of the vehicle. The effectiveness of the method is demonstrated through a case study.
Article
Engineering, Marine
Tu Lv, Mingjun Zhang, Yujia Wang
Summary: This paper proposes a prediction-based region tracking control scheme for an autonomous underwater vehicle (AUV) to solve the problems of overshoot and high energy consumption. By predicting the future position of AUV and the outer boundary of the desired region, the controller is designed accordingly. Furthermore, an optimization scheme considering the desired region is proposed to address the output saturation issue.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Geological
Nathaniel Wagner, Micaela Largent, Jonathan P. Stewart, Christine Beyzaei, Debra Murphy, Jeremy Butkovich, John A. Egan
Summary: Old Bay Clays are overconsolidated silty clays of Pleistocene age found along the margins of San Francisco Bay. A recent project, Millennium Tower, induced primary consolidation followed by secondary compression in these materials. Testing showed that following soil unloading, the rate of secondary compression slows relative to the initial condition after primary consolidation.
JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING
(2021)
Article
Oceanography
Luc Rainville, Craig M. Lee, K. Arulananthan, S. U. P. Jinadasa, Harindra J. S. Fernando, W. N. C. Priyadarshani, Hemantha Wijesekera
Summary: This study presents sustained observations of the ocean around Sri Lanka using autonomous gliders. The observations reveal the complex and variable circulation patterns connecting the Bay of Bengal, Arabian Sea, and Indian Ocean. The results highlight the importance of both surface and subsurface flows in the water exchanges between the Arabian Sea and the Bay of Bengal, emphasizing the need for long-term observations to understand the circulation pathways and dynamics in this region.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Engineering, Marine
Haoliang Wang, Dan Wang, Fumin Zhang, Lu Liu, Tianlin Wang, Zhouhua Peng
Summary: This paper presents a self-triggered three-dimensional coordinated path following controller design method for networked under-actuated underwater gliders, which can handle internal model uncertainties and external ocean disturbances.
Article
Engineering, Multidisciplinary
Wen-Qing Zhang, Liang-Long Da, De-Yan Tian, Qin-Dong Sun, Wen-Long Wang, Wen-Jing Chen
Summary: This paper analyzes the characteristics of underactuation of underwater glider, establishes a complete 6DOF model, designs a nonlinear adaptive control strategy, and verifies the controller's performance in marine experiments. The stability range against the interference of sea currents is provided.
MATHEMATICAL PROBLEMS IN ENGINEERING
(2021)
Article
Veterinary Sciences
Rose Delima N'Guessan, Kathrin Heitz-Tokpa, Djedou Martin Amalaman, Sopi Mathilde Tetchi, Vessaly Kallo, Andree Prisca Ndjoug Ndour, Govella Nicodem, Issiaka Kone, Katharina Kreppel, Bassirou Bonfoh
Summary: Despite the fact that death from rabies is 100% preventable, canine rabies still causes a significant number of deaths worldwide, especially in Africa. In Cote d'Ivoire, the high drop-out rate of post-exposure prophylaxis (PEP) treatment among people exposed to dog bites remains a threat. A study conducted in the San-Pedro department of Cote d'Ivoire identified perception bias and low attendance at healthcare centers as key reasons for dropping out of treatment.
FRONTIERS IN VETERINARY SCIENCE
(2022)
Article
Engineering, Marine
Guanzhong Chen, Yue Shen, Nanzhu Qu, Dianrui Wang, Bo He
Summary: This paper proposes a control architecture of autonomous underwater vehicle (AUV) for coverage mission in irregular region (CMIR) with an improved task planner. Through simulation experiments and sea trials, the feasibility of the control architecture in actual marine environment has been validated.
Article
Remote Sensing
Leiyang Zhong, Ying Zhou, Song Gao, Zhaoyang Yu, Zhifeng Ma, Xiaoming Li, Yang Yue, Jizhe Xia
Summary: This study analyzes the impact of lockdown measures on population mobility using high spatiotemporal resolution mobile-phone location data. The study found that lockdown measures led to a general reduction in population mobility, but the structural changes in mobility varied significantly between the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) and the San Francisco Bay Area (SBA).
INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION
(2022)
Article
Marine & Freshwater Biology
Juan A. Jimenez-Rincon, Carlos J. Gonzalez, Alfredo Izquierdo, Oscar Alvarez
Summary: This study applies a two-dimensional, non-linear, finite difference, hydrodynamic model to investigate the changes in tidal current asymmetries along the San Pedro channel. The results show that after reconnecting the main channel to a previously desiccated tidal lagoon, the current asymmetries become stronger and directed towards ebb. The influence of upstream intertidal flats on tidal current asymmetries and residual currents is found to be more pronounced during spring tides.
ESTUARINE COASTAL AND SHELF SCIENCE
(2023)
Article
Engineering, Marine
Tao Chen, Xingru Qu, Zhao Zhang, Xiao Liang
Summary: This article presents a distributed cooperative path-maneuvering control approach for multiple autonomous underwater vehicles, using boustrophedon motions and trigonometric functions to generate parameterized paths, employing distributed maneuvering control laws for accuracy, and developing consensus protocols through graph theory to maintain formation configurations.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Civil
Floriana Petrone, Norman Abrahamson, David McCallen, Arben Pitarka, Arthur Rodgers
Summary: This study evaluates the first EQSIM ground-motion simulations generated for the San Francisco Bay Area and proposes a methodology for their evaluation. The objective is to enhance confidence in the simulated motions and offer physics-based interpretations to improve simulation models, while also exploring the implications of using simulated ground motions for site-specific structural assessments.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2021)
Article
Oceanography
Daniel L. Rudnick, Nikolaos D. Zarokanellos, Joaquin Tintore
Summary: A four-dimensional survey using underwater gliders has identified the pathways of subduction at the Almeria-Oran Front in the western Mediterranean Sea. The data collected by the gliders revealed a close relationship between the movement of the front and the vertical velocity, as well as a heat flux structure that would cause restratification of the front.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Oceanography
Maximo Garcia-Jove, Baptiste Mourre, Nikolaos D. Zarokanellos, Pierre F. J. Lermusiaux, Daniel L. Rudnick, Joaquin Tintore
Summary: This study analyzed the development of vertical velocities at the main fronts of the Alboran Sea using a high-resolution realistic simulation and glider observations. The Western Alboran Gyre Front was found to be amplified by an across-front ageostrophic circulation generated by the intensification of the front and along down-front winds. On the other hand, the Eastern Alboran Gyre Front exhibited a complex pattern of vertical velocities associated with frontal intensification, which resulted from a cold filament advected in the interior of the Mediterranean Sea. The processes responsible for the vertical velocities development were found to be different in the two fronts.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Oceanography
Nikolaos D. Zarokanellos, Daniel L. Rudnick, Maximo Garcia-Jove, Baptiste Mourre, Simon Ruiz, Ananda Pascual, Joaquin Tintore
Summary: Ocean fronts are important areas for supporting phytoplankton production and the transport of biogeochemical properties. This study used a combination of glider observations, remote sensing, and modeling simulations to study the Almeria-Oran front. The observations revealed spatial and temporal changes in the front and strong horizontal density gradients.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Oceanography
Julie Jakoboski, Robert E. E. Todd, W. Brechner Owens, Kristopher B. B. Karnauskas, Daniel L. L. Rudnick
Summary: The Galapagos Archipelago is influenced by the Pacific Equatorial Undercurrent (EUC) which results in instabilities that may impact the Galapagos Cold Pool. Observations have shown that these currents can result in opposite sign vorticity and various instabilities in the region.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Oceanography
Alexander L. Kurapov, Daniel L. Rudnick, Brandy T. Cervantes, Craig M. Risien
Summary: The measurable impact of the El Nino remote oceanic forcing mechanism along the US West Coast during the major heat wave period of 2014-2016 is analyzed using a regional ocean circulation model. The study shows that El Nino-related oceanic anomalies propagate along the coast and influence the variability off Oregon.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Oceanography
Eugenio Cutolo, Ananda Pascual, Simon Ruiz, T. M. Shaun Johnston, Mara Freilich, Amala Mahadevan, Andrey Shcherbina, Pierre-Marie Poulain, Tamay Ozgokmen, Luca R. Centurioni, Daniel L. Rudnick, Eric D'Asaro
Summary: Intensive hydrographic and horizontal velocity measurements in the Alboran Sea were used to study the three-dimensional dynamics of a frontal system. A multi-variate variational analysis method was applied to reconstruct the hydrographic fields, and the results showed that this method improved the understanding of (sub)-mesoscale frontal dynamics compared to classical optimal interpolation. The estimation of vertical velocity and the analysis of nutrient distribution further revealed the characteristics and motion of the frontal system.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Environmental Sciences
Andrew R. Thompson, Eric P. Bjorkstedt, Steven J. Bograd, Jennifer L. Fisher, Elliott L. Hazen, Andrew Leising, Jarrod A. Santora, Erin V. Satterthwaite, William J. Sydeman, Michaela Alksne, Toby D. Auth, Simone Baumann-Pickering, Noelle M. Bowlin, Brian J. Burke, Elizabeth A. Daly, Heidi Dewar, John C. Field, Newell T. Garfield, Ashlyn Giddings, Ralf Goericke, John Hildebrand, Cheryl A. Horton, Kym C. Jacobson, Michael G. Jacox, Jaime Jahncke, Michael Johns, Joshua Jones, Raphe M. Kudela, Sharon R. Melin, Cheryl A. Morgan, Catherine F. Nickels, Rachael A. Orben, Jessica M. Porquez, Elan J. Portner, Antonella Preti, Roxanne R. Robertson, Daniel L. Rudnick, Keith M. Sakuma, Isaac D. Schroeder, Owyn E. Snodgrass, Sarah Ann Thompson, Jennifer S. Trickey, Pete Warzybok, William Watson, Edward D. Weber
Summary: A La Nina occurred in the California Current Ecosystem in 2021, with many indicators resembling past La Ninas, but with some differences as well. Further study is needed to understand the effects of La Nina on this ecosystem.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Benjamin E. Werb, Daniel L. Rudnick
Summary: This analysis recalculates the empirical orthogonal functions (EOFs) and principal components (PCs) of sea surface temperature (SST) in the North Pacific from 1950 to 2021. It finds that the persistent marine heatwaves since 2014 have fundamentally changed the first EOF and PC of SST, which is known as the Pacific Decadal Oscillation (PDO). The study also shows that the second EOF of SST has changed in both spatial pattern and explained variance. Therefore, the PDO and other EOF-based metrics may not be as useful in the future due to ongoing climate change.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Engineering, Ocean
James N. Moum, Daniel L. Rudnick, Emily L. Shroyer, Kenneth G. Hughes, Benjamin D. Reineman, Kyle Grindley, Jeffrey T. Sherman, Pavan Vutukur, Craig Van Appledorn, Kerry Latham, Aurelie J. Moulin, T. M. Shaun Johnstonb
Summary: A new autonomous turbulence profiling float called Flippin' xSOLO (FxS) has been designed, built, and tested in field trials off Oregon. It is equipped with a full suite of turbulence sensors and can measure through the sea surface. FxS provides intensive profiling measurements of the upper ocean and estimates wave height spectra and significant wave height during surfacing. The inclusion of turbulence measurements on autonomous profilers improves our understanding of the ocean's interior.
JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY
(2023)
Article
Oceanography
Noel G. Brizuela, T. M. Shaun Johnston, Matthew H. Alford, Olivier Asselin, Daniel L. Rudnick, James N. Moum, Elizabeth J. Thompson, Shuguang Wang, Chia-Ying Lee
Summary: In this study, data from 6 profiling floats were used to reconstruct three-dimensional fields of temperature, salinity, and velocity around the fast-moving Super Typhoon Mangkhut. Observational estimates of vorticity and divergence matched the output from a 3D coupled model, and their relationship with vertical velocities was explained by a linear theoretical statement of inertial pumping. The vertical profiles of temperature and salinity showed gradual mixing of the upper ocean and the generation of near-inertial waves. Watermass transformation analyses indicated high diffusion coefficients above a certain depth up to 600 km behind the typhoon.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Engineering, Ocean
Alice S. Ren, Daniel L. Rudnick, Alistair Twombly
Summary: This study describes the drift characteristics of the Sea-Bird 63 dissolved oxygen optode sensors over a 5-year period. The sensors exhibited larger drift during 100-day deployments compared to 100-day storage periods. The sensor behavior was modeled and a correction procedure was proposed to improve the accuracy of the measurements.
JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY
(2023)
Article
Environmental Sciences
Robert E. Todd, Alice S. Ren
Summary: As the western boundary current of the North Atlantic, the Gulf Stream is crucial in the climate system. Recent research shows that from 2001 to 2023, the Gulf Stream west of 68 degrees W has experienced surface-intensified warming and a lateral shift towards its cooler side. These changes have resulted in increased stratification in the upper ocean.
NATURE CLIMATE CHANGE
(2023)
Article
Meteorology & Atmospheric Sciences
Kenneth G. Hughes, James N. Moum, Daniel L. Rudnick
Summary: Autonomous and expendable profiling-float arrays in the Argo Program require reliable data transmission from remote sites. To address the issue of limited satellite data transfer rates, a scheme for onboard data reduction is proposed and tested with turbulence data obtained with a modified SOLO-II profiling float.
Article
Oceanography
Harvey E. Seim, Dana Savidge, Magdalena Andres, John Bane, Catherine Edwards, Glen Gawarkiewicz, Ruoying He, Robert E. Todd, Michael Muglia, Joseph Zambon, Lu Han, Shun Mao
Summary: The Processes driving Exchange At Cape Hatteras (PEACH) program aims to study seawater exchanges between the continental shelf and the open ocean near Cape Hatteras, North Carolina. This research is motivated by the unique oceanography of the region and focuses on the roles of wind forcing, Gulf Stream forcing, and density gradients in driving exchange. Through observational efforts and modeling, the program has made findings on mean circulation, export from the shelf, Gulf Stream variability, and Hatteras Front position variability, with future analyses planned.
Article
Oceanography
Alice S. Ren, Daniel L. Rudnick
Summary: This study examines the across-shore propagation characteristics of subthermocline eddies (STEs) in the California Current System (CCS) using 13 years of sustained coastal glider measurements. The results show that anticyclonic STEs propagate with high salinity, high temperature, and low dissolved oxygen anomalies, indicating their role in transporting water masses from the coast to offshore. However, there is only weak correlation between STEs and sea surface height expression.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)