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1. (2024) Coastal Pioneer Mid-Atlantic Bight Mobile Asset Autonomous Underwater Vehicles (CP16MOAS)

   https://doi.org/10.58046/ooi-cp16moas  

   NSF_Ocean_Observatories_Initiative (January 2024, US NSF Ocean Observatories Initiative)

   Coastal Autonomous Underwater Vehicles (AUVs) are Mobile Assets that survey the area in and around the array of moorings at the Coastal Pioneer MAB Array. Two Coastal AUVs (HII REMUS-600 AUVs) travel along transects across the shelf-break frontal system extending beyond the mooring array, covering an area approximately 1000 square kilometers in size centered on the array of moorings. The primary role of the AUVs is to resolve cross- and along-front “eddy fluxes” due to frontal instabilities, wind forcing, and mesoscale variability. These AUVs travel along saw-toothed transects, penetrating the sea surface and diving down to a maximum depth of 600 meters. 

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2. Conformal Wideband Microstrip Patch Antennas on Cylindrical Platforms

   Mitha, Tanzeela; Pour, Maria (November 2018, Progress in electromagnetics research)

   A conformal wideband antenna is investigated and compared with its planar counterpart. First, a planar U-slot patch with about 43% fractional impedance bandwidth is designed. Then, it is mounted on a conformal cylindrical structure. It is observed that the fractional impedance bandwidth of the resulting conformal antenna increases to 50%, when it is bent along the H-plane. It is also found that the cross polarization discrimination of the antenna is improved. The effects of the arc angle and radius of the cylinder on the impedance bandwidth and radiation characteristics of the antenna are extensively studied. The conformal antenna was fabricated on a thin film of Kapton and tested. The measured and simulated results closely resembled each other. 

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3. (2014) Coastal Pioneer New England Shelf Mobile Assets (CP05MOAS)

   https://doi.org/10.58046/ooi-cp05moas  

   NSF_Ocean_Observatories_Initiative (January 2014, US NSF Ocean Observatories Initiative)

   Two kinds of Mobile Assets survey the area in and around the array of moorings at the Coastal Pioneer Array – Coastal Gliders and Coastal Autonomous Underwater Vehicles (AUVs).\n\nAn array of 6 Coastal Gliders (Teledyne-Webb Slocum Gliders) sample large, mesoscale features through a broad region (130 x 185 km) of the outer continental shelf between the shelf break and the Gulf Stream. The role of these gliders in monitoring this broader area is to resolve rings, eddies and meanders from the Gulf Stream as they impinge on the shelf break front. These Teledyne-Webb Slocum Gliders fly through the water column along saw-tooth paths, penetrating the sea surface and diving down to a maximum depth of 1000 meters.\n\nAn array of two Coastal AUVs (REMUS-600 AUVs) travel along transects across the shelf-break frontal system extending beyond the mooring array, covering an area approximately 80 x 100 km in size centered on the array of moorings. The primary role of the AUVs is to resolve cross- and along-front “eddy fluxes” due to frontal instabilities, wind forcing, and mesoscale variability. These AUVs travel along saw-toothed transects, penetrating the sea surface and diving down to a maximum depth of 600 meters. 

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4. Reinforcement Learning-Based Multi-AUV Adaptive Trajectory Planning for Under-Ice Field Estimation

   https://doi.org/10.3390/s18113859  

   Wang, Chaofeng; Wei, Li; Wang, Zhaohui; Song, Min; Mahmoudian, Nina (November 2018, Sensors)

   This work studies online learning-based trajectory planning for multiple autonomous underwater vehicles (AUVs) to estimate a water parameter field of interest in the under-ice environment. A centralized system is considered, where several fixed access points on the ice layer are introduced as gateways for communications between the AUVs and a remote data fusion center. We model the water parameter field of interest as a Gaussian process with unknown hyper-parameters. The AUV trajectories for sampling are determined on an epoch-by-epoch basis. At the end of each epoch, the access points relay the observed field samples from all the AUVs to the fusion center, which computes the posterior distribution of the field based on the Gaussian process regression and estimates the field hyper-parameters. The optimal trajectories of all the AUVs in the next epoch are determined to maximize a long-term reward that is defined based on the field uncertainty reduction and the AUV mobility cost, subject to the kinematics constraint, the communication constraint and the sensing area constraint. We formulate the adaptive trajectory planning problem as a Markov decision process (MDP). A reinforcement learning-based online learning algorithm is designed to determine the optimal AUV trajectories in a constrained continuous space. Simulation results show that the proposed learning-based trajectory planning algorithm has performance similar to a benchmark method that assumes perfect knowledge of the field hyper-parameters. 

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5. Conformal geometry from entanglement

   https://doi.org/10.21468/SciPostPhys.18.3.102  

   Kim, Isaac H; Li, Xiang; Lin, Ting-Chun; McGreevy, John; Shi, Bowen (January 2025, SciPost Physics)

   In a physical system with conformal symmetry, observables depend on cross-ratios, measures of distance invariant under global conformal transformations (conformal geometry for short). We identify a quantum information-theoretic mechanism by which the conformal geometry emerges at the gapless edge of a 2+1D quantum many-body system with a bulk energy gap. We introduce a novel pair of information-theoretic quantities(\mathfrak{c}_{\textrm{tot}}, \eta) $({𝔠}_{\text{tot}},\eta )$that can be defined locally on the edge from the wavefunction of the many-body system, without prior knowledge of any distance measure. We posit that, for a topological groundstate, the quantity\mathfrak{c}_{\textrm{tot}} ${𝔠}_{\text{tot}}$is stationary under arbitrary variations of the quantum state, and study the logical consequences. We show that stationarity, modulo an entanglement-based assumption about the bulk, implies (i)\mathfrak{c}_{\textrm{tot}} ${𝔠}_{\text{tot}}$is a non-negative constant that can be interpreted as the total central charge of the edge theory. (ii)\eta $\eta$is a cross-ratio, obeying the full set of mathematical consistency rules, which further indicates the existence of a distance measure of the edge with global conformal invariance. Thus, the conformal geometry emerges from a simple assumption on groundstate entanglement. We show that stationarity of\mathfrak{c}_{\textrm{tot}} ${𝔠}_{\text{tot}}$is equivalent to a vector fixed-point equation involving\eta $\eta$, making our assumption locally checkable. We also derive similar results for 1+1D systems under a suitable set of assumptions. 

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