检索结果-内蒙古大学图书馆

oceanS

作者： Chase Pixa Kevin Manganini Alyson Myers Anna PM Michel MIT-WHOI Joint Program in Applied Ocean Science and Engineering Cambridge USA Applied Ocean Physics and Engineering Woods Hole Oceanographic Institution USA Fearless Fund Washington D.C. USA

Since 2011, Sargassum, a free-floating macroalgae, has been causing significant ecological and economic damage to coastal regions in the Northern Equatorial Atlantic due to its voluminous blooms. To better understand the fate and effects of Sargassum, approaches are needed to track its transport. Here we developed a low-cost drifter, designed to entangle with Sargassum, to aid in its tracking providing in situ movement data to ground-truth models and supplementing gaps in satellite imaging. The results of 27 drifter designs and five days of field trials are presented. The successful entanglement and tracking with the Sargassum demonstrated here can guide future studies to further our understanding of the movement of Sargassum in the great Atlantic Sargassum belt (GASB).

关键词：

来源：评论

学校读者我要写书评

暂无评论

The Ceres Human Exploration and Transit Architecture (CHEATA): A Mission Architecture for Small Bodies Exploration 73

The Ceres Human Exploration and Transit Architecture (CHEATA...

引用

73rd International Astronautical Congress, IAC 2022

作者： Todd, Jessica Gentgen, Chloe Porter, Allison Bellisle, Rachel Martell, Benjamin Hoffman, Jeffrey Department of Aeronautics and Astronautics Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering Woods Hole Oceanographic Institution Woods HoleMA United States Harvard-MIT Health Sciences and Technology Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States

The Ceres Human Exploration and Transit Architecture (CHEATA) is a conceptual mission developed to enable human exploration of Ceres and other small bodies in the asteroid belt. These small bodies present tempting targets for future human exploration, providing insight into the evolution of our solar system, potentially containing environments of interest to astrobiologists, and acting as water- and mineral-rich stepping stones for outer solar system exploration. Minimizing radiation exposure and mission duration while maximizing surface science operations on the surface of Ceres was the critical driving requirement for this design reference mission. Key elements of the design include (1) a low gravity hopping vehicle using vacuum retro-propulsion and LOX/Methane propellant, taking advantage of the low gravity environment for regional exploration and surface operations on Ceres, (2) a bimodal nuclear thermal propulsion (NTP) system that utilizes liquid hydrogen and a reusable CERMET core, and (3) an active high-temperature superconducting magnet system, complemented by a passive high-density polyethylene system, to mitigate crew exposure to galactic cosmic radiation and solar energetic particle events. A transit habitat vehicle is assembled in cislunar space and used to ferry astronauts to Ceres orbit. The study also details breakdowns of the human countermeasures employed to address the effects of microgravity and isolation. The CHEATA mission concept was initially presented at the IEEE Aerospace Conference in 2022. The mission architecture has been updated to now include the design of additional spacecraft and habitation subsystems. These include the design of an Environmental Control and Life Support System, secondary propulsion for corrections, small maneuvers, and attitude control, but also more in-depth power and thermal management systems. The propellant storage was refined with the inclusion of zero boil-off technology for the Liquid Hydrogen tanks. A detail

关键词： Liquefied gases

来源：评论

学校读者我要写书评

暂无评论

Multi-Robot Distributed Semantic Mapping in Unfamiliar Environments through Online Matching of Learned Representations

Multi-Robot Distributed Semantic Mapping in Unfamiliar Envir...

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： Stewart Jamieson Kaveh Fathian Kasra Khosoussi Jonathan P. How Yogesh Girdhar MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering Massachusetts Institute of Technology (MIT) Woods Hole Oceanographic Institution (WHOI)

We present a solution to multi-robot distributed semantic mapping of novel and unfamiliar environments. Most state-of-the-art semantic mapping systems are based on supervised learning algorithms that cannot classify novel observations online. While unsupervised learning algorithms can invent labels for novel observations, approaches to detect when multiple robots have independently developed their own labels for the same new class are prone to erroneous or inconsistent matches. These issues worsen as the number of robots in the system increases and prevent fusing the local maps produced by each robot into a consistent global map, which is crucial for cooperative planning and joint mission summarization. Our proposed solution overcomes these obstacles by having each robot learn an unsupervised semantic scene model online and use a multiway matching algorithm to identify consistent sets of matches between learned semantic labels belonging to different robots. Compared to the state of the art, the proposed solution produces 20-60% higher quality global maps that do not degrade even as many more local maps are fused.

关键词： Conferences Semantics Supervised learning Buildings Bandwidth Path planning Classification algorithms

来源：评论

学校读者我要写书评

暂无评论

Distributed Certifiably Correct Range-Aided SLAM

arXiv

引用

arXiv 2025年

作者： Thoms, Alexander Papalia, Alan Velasquez, Jared Rosen, David M. Narasimhan, Sriram Sensing and Robotics for Infrastructure Laboratory University of California Los Angeles Los Angeles United States The Massachusetts Institute of Technology The MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering Woods Hole CambridgeMA United States Robust Autonomy Lab Northeastern University BostonMA United States

Reliable simultaneous localization and mapping (SLAM) algorithms are necessary for safety-critical autonomous navigation. In the communication-constrained multi-agent setting, navigation systems increasingly use point-to-point range sensors as they afford measurements with low bandwidth requirements and known data association. The state estimation problem for these systems takes the form of range-aided (RA) SLAM. However, distributed algorithms for solving the RA-SLAM problem lack formal guarantees on the quality of the returned estimate. To this end, we present the first distributed algorithm for RA-SLAM that can efficiently recover certifiably globally optimal solutions. Our algorithm, distributed certifiably correct RA-SLAM (DCORA), achieves this via the Riemannian Staircase method, where computational procedures developed for distributed certifiably correct pose graph optimization are generalized to the RA-SLAM problem. We demonstrate DCORA’s efficacy on real-world multi-agent datasets by achieving absolute trajectory errors comparable to those of a state-of-the-art centralized certifiably correct RA-SLAM algorithm. Additionally, we perform a parametric study on the structure of the RA-SLAM problem using synthetic data, revealing how common parameters affect DCORA’s performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Navigation systems

来源：评论

学校读者我要写书评

暂无评论

Multi-robot distributed semantic mapping in unfamiliar environments through online matching of learned representations

arXiv

引用

arXiv 2021年

作者： Jamieson, Stewart Fathian, Kaveh Khosoussi, Kasra How, Jonathan P. Girdhar, Yogesh The MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering United States United States United States

关键词： Industrial robots

来源：评论

学校读者我要写书评

暂无评论

Glacial isostatic adjustment shifted early Holocene river hydrology in Maine, USA

引用

Geology 2025年第5期53卷 446-450页

作者： Sanborn, Lily H. Pico, Tamara Donnelly, Jeffrey P. Perron, J. Taylor Massachusetts Institute of Technology Woods Hole Oceanographic Institution Joint Program in Oceanography/Applied Ocean Science and Engineering Cambridge 02139 Woods HoleMA02543 United States Earth & Planetary Sciences Department University of California Santa Cruz Santa CruzCA95064 United States Department of Geology & Geophysics Woods Hole Oceanographic Institution Woods HoleMA02543 United States Department of Earth Atmospheric & Planetary Sciences Massachusetts Institute of Technology CambridgeMA02139 United States

Glacial isostatic adjustment produces crustal deformation capable of altering the slope of the landscape and diverting surface water drainage, thereby modulating the hydraulic conditions that govern river evolution. These effects can be especially important near the margins of ice sheets. In Maine, USA, post-glacial changes in sedimentation within major river systems have been interpreted as the result of regional tilting and drainage rerouting due to glacial isostatic adjustment. In this study, we model isostatic adjustment driven by retreat of the Laurentide Ice Sheet, quantify the associated tilting and drainage rerouting, and explore how these changes impacted sediment transport in Maine’s rivers. Through an analysis of changes to river slope and drainage area produced by glacial isostatic adjustment, we show that ice sheet retreat altered the median sediment grain size that rivers could entrain. We also find support for previous estimates of the timing and direction of drainage reversal at Moosehead Lake, Maine’s largest lake. Our results suggest that the history of sedimentation in Maine’s rivers reflects time-dependent effects of glacial isostatic adjustment that are superimposed on any changes in runoff associated with deglaciation. Further, our case study demonstrates that isostatic adjustment affects alluvial channel evolution and sediment delivery to the coastline for several millennia after an ice sheet retreats. © 2025 Geological Society of America.

关键词： Glacial geology

来源：评论

学校读者我要写书评

暂无评论

Tracking Sargassum in the Caribbean: The Deployment and Validation of a Low-Cost Surface Drifter

SSRN

引用

SSRN 2023年

作者： Pixa, Chase Manganini, Kevin Myers, Alyson Michel, Anna P.M. Department of Applied Ocean Physics and Engineering Woods Hole Oceanographic Institution 266 Woods Hole Road Woods HoleMA02543 United States Department of Mechanical Engineering Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering Cambridge and Woods Hole MA United States Fearless Fund 3029 Woodland Drive NW WashingtonDC20008 United States

Sargassum blooms have been causing significant ecological and economic damage to coastal regions in the Northern Equatorial Atlantic since 2011. To better understand the movement and effects of this macroalgae, there is a need to track its transport. In this study, a low-cost drifter was deployed, designed to entangle with Sargassum and aid in its tracking. The design was based on the results of twenty-seven drifter designs and five days of field trials. The tracking data was validated using gridded wind and current products, as well as high resolution satellite imagery. The successful entanglement and tracking with the Sargassum demonstrated in this study can provide in situ movement data to ground-truth models and supplement gaps in satellite imaging. The results can guide future studies and further our understanding of its movement in the great Atlantic Sargassum belt (GASB). © 2023, The Authors. All rights reserved.

关键词： Costs

来源：评论

学校读者我要写书评

暂无评论

Nitrous Oxide Distributions in the Oxygenated Water Column of the Sargasso Sea

引用

Atmosphere 2023年第3期61卷 173-185页

作者： Annaliese C. S. Meyer Jay T. Cullen Damian S. Grundle 1 Earth Atmospheric and Planetary Sciences Massachusetts Institute of Technology Cambridge MA USA2 Marine Chemistry and Geochemistry Woods Hole Oceanographic Institution Falmouth MA USA3 Bermuda Institute of Ocean Sciences St. George’s Bermuda4 Chemical Oceanography MIT-WHOI Joint Program in Oceanography Falmouth MA USA 5 School of Earth and Ocean Sciences University of Victoria Victoria Canada 3 Bermuda Institute of Ocean Sciences St. George’s Bermuda6 School of Ocean Futures and School of Earth and Space Exploration Arizona State University Tempe AZ USA

ABSTRACTThis study presents dissolved nitrous oxide (N2O) concentrations in the water column at the Bermuda Atlantic Time-series Study (BATS) station and uses a subset of these measurements to estimate air-to-sea flux for four specific time points between September 2018 and June 2019. N2O concentrations at BATS were in the range of 4.0 nmol L−1–16.9 nmol L−1, with vertical profiles which were the mirror inverse of dissolved oxygen. Regardless of season, N2O concentration maxima were found within the oxygen minimum zone (OMZ). The highest maximum N2O values were observed in November and lowest in October. As the water column at BATS remains consistently at dissolved oxygen concentrations greater than 140 µmol L−1, and therefore aerobic, we assume that the bulk of N2O production occurs through nitrification. A nitrification source is supported by a correlation between excess N2O (ΔN2O) below the mixed layer, apparent oxygen utilization (AOU) and nitrate concentrations. We estimate a pooled average yield of 0.027% to 0.038% N2O from nitrification at BATS. Finally, estimates of air–sea exchange of N2O using regional average monthly wind speeds indicated that this region acts as a weak source or a sink of atmospheric N2O, and varies between ***[Traduit par la rédaction] Cette étude présente les concentrations d’oxyde de diazote (N2O) dissous dans la colonne d’eau à la station BATS (Bermuda Atlantic Time-series Study) et emploie un sous-ensemble de ces mesures pour estimer le flux air-mer pour quatre points temporels spécifiques entre septembre 2018 et juin 2019. Les concentrations de N2O à la station BATS étaient comprises entre 4,0 nmol L−1et 16,9 nmol L−1, avec des profils verticaux qui étaient l’inverse de l’oxygène dissous. Quelle que soit la saison, les concentrations maximales de N2O se trouvaient dans la zone de minimum d’oxygène. Les valeurs maximales de N2O les plus élevées ont été observées en novembre et les plus faibles en octobre. Comme la colonne

关键词： nitrous oxide Bermuda Atlantic Time Series air–sea gas exchange greenhouse gas nitrification cavity ring down spectrometer

来源：评论

学校读者我要写书评

暂无评论

Enabling Under-Ice Geochemical Observations with a Size, Weight, and Power-Constrained Robot

arXiv

引用

arXiv 2022年

作者： Horowitz, Jess Preston, Victoria Michel, Anna P.M. Mechanical Engineering Massachusetts Institute of Technology Cambridge United States MIT-WHOI Joint Program Massachussetts Institute of Technology Cambridge United States Applied Ocean Physics and Engineering Woods Hole Oceanographic Institution Woods Hole United States

Estimates of greenhouse gas emissions from Arctic estuarine environments are dominated by in situ summer-time ice-free dissolved gas measurements due to the logistical ease of performing field observations in these conditions. Recent evidence in coastal Arctic environments, however, has demonstrated that dissolved methane (CH4) and carbon dioxide (CO2) are strongly seasonally variable, and at least one significant gas ventilation event occurs during the spring freshet. Whether the Arctic serves as a source or sink of greenhouse emissions has significant implications on modeling climate change and its feedback mechanisms. To enable higher resolution spatiotemporal measurements of dissolved gases in typically undersampled conditions, remotely operated vehicles (ROVs) can be used to extract near continuous water samples below ice before and during the spring freshet. Here, we present a size, weight, and power-constrained (SWAP) underwater vehicle (UV) and novel geochemical sampling system suitable for taking under-ice geochemical observations and demonstrate the proposed system in a field-analog setting for Arctic estuarine studies. Copyright © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide

来源：评论

学校读者我要写书评

暂无评论

Corrigendum to “Lipid composition, caloric content, and novel oxidation products from microbial communities within seasonal pack ice cores” [Geochimica et Cosmochimica Acta 368 (2024) 12–23]

引用

Geochimica et Cosmochimica Acta 2024年 382卷 161-161页

作者： Henry C. Holm Helen F. Fredricks Shavonna M. Bent Daniel P. Lowenstein Kharis R. Schrage Benjamin A.S. Van Mooy Marine Chemistry and Geochemistry Department Woods Hole Oceanographic Institution Woods Hole MA 02543 USA MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering Cambridge MA 02139 USA

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：