检索结果-内蒙古大学图书馆

Correction: Reverse engineering environmental metatranscriptomes clarifies best practices for eukaryotic assembly

BMC bioinformatics 2023年第1期24卷 185页

作者： Arianna I Krinos Natalie R Cohen Michael J Follows Harriet Alexander MIT-WHOI Joint Program in Oceanography and Applied Ocean Science and Engineering Cambridge and Woods Hole MA USA. akrinos@mit.edu. Department of Biology Woods Hole Oceanographic Institution Woods Hole MA USA. akrinos@mit.edu. Department of Earth Atmospheric and Planetary Science Massachusetts Institute of Technology Cambridge MA USA. akrinos@mit.edu. Skidaway Institute of Oceanography University of Georgia Savannah GA USA. Department of Earth Atmospheric and Planetary Science Massachusetts Institute of Technology Cambridge MA USA. Department of Biology Woods Hole Oceanographic Institution Woods Hole MA USA. halexander@whoi.edu.

来源：评论

学校读者我要写书评

暂无评论

Wireless Data Harvesting Using the AUV Sentry and whoi Optical Modem

Wireless Data Harvesting Using the AUV Sentry and WHOI Optic...

引用

Oceans MTS/IEEE Washington (Conference)

作者： Clifford Pontbriand Norm Farr Johanna Hansen James C. Kinsey Leo-Paul Pelletier Jonathan Ware Dehann Fourie Advanced Ocean Physics and Engineering Department Woods Hole Oceanographic Institution MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering CSAIL

ISBN: (纸本)9781467393744

The optical communications group at Woods Hole oceanographic Institution has demonstrated wireless optical transmission of data from a seafloor node to the Sentry AUV. This effort is based on the latest version of the optical modem under continual development at whoi, and it builds on fieldwork conducted in 2012 and 2013 during which we successfully transferred data from seafloor-deployed optical modem systems using a wire-lowered optical modem from a ship. While our previous work used a high-bandwidth optical modem for the data uplink and an acoustic modem "backlink" to control the file transfer, the optical modem described in this paper supports fully bidirectional optical communication - essentially subsea WiFi. A subordinate objective of our work was to literally map the operational space for an AUV-bottom node optical link. Armed with this spatial map, we can plan for future "connected" AUV operations in support of data mule, inspection, manipulation, and other underwater semi-autonomous tasks.

关键词： Underwater optical communications Freespace Optical modem Underwater wireless communications A UV Data mule

来源：评论

学校读者我要写书评

暂无评论

oceanographic pursuit: Networked control of multiple vehicles tracking dynamic ocean features

引用

Methods in Oceanography 2014年 10卷 21-43页

作者： Reed, Brooks Hover, Franz Massachusetts Institute of Technology Department of Mechanical Engineering Cambridge 02139 MA United States MIT-WHOI Joint Program Woods Hole Oceanographic Institution Woods Hole MA United States

We present an integrated framework for joint estimation and pursuit of dynamic features in the ocean, over large spatial scales and with multiple collaborating vehicles relying on limited communications. Our approach uses ocean model predictions to design closed-loop networked control at short time scales, and the primary innovation is to represent model uncertainty via a projection of ensemble forecasts into local linearized vehicle coordinates. Based on this projection, we identify a stochastic linear time-invariant model for estimation and control design. The methodology accurately decomposes spatial and temporal variations, exploits coupling between sites along the feature, and allows for advanced methods in communication-constrained control. Simulations with three example datasets successfully demonstrate the proof-of-concept. © 2014 The Authors.

关键词： Autonomous underwater vehicles Collaborative control Ensemble forecasts Feature tracking Linearization System identification

来源：评论

学校读者我要写书评

暂无评论

Temporal and spatial variability in vessel noise on tropical coral reefs

引用

Proceedings of Meetings on Acoustics 2016年第1期27卷

作者： Maxwell B. Kaplan T. Aran Mooney Marc O. Lammers Eden Zang 1Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program in Oceanography/Applied Ocean Science and Engineering Cambridge MA USA mkaplan@whoi.edu 2Biology Department Woods Hole Oceanographic Institution Woods Hole MA USA amooney@whoi.edu 3Hawaii Institute of Marine Biology Kaneohe HI Oceanwide Science Institute Honolulu HI USA lammers@hawaii.edu 4Oceanwide Science Institute Honolulu HI USA edenzang@***

Coral reef soundscapes are dynamic, demonstrating amplitude and spectral variability across timescales from seconds to seasons. Some of this variability can result from spatiotemporally heterogeneous patterns of human activity. To characterize this variability and the extent to which anthropogenic sound can modify the biological soundscape, seven Hawaiian reefs were equipped with acoustic recorders operating on a 10% duty cycle for 16 months. Spatially, vessel activity was acoustically detected unevenly across reefs; for example, vessels were acoustically present almost every day at a popular snorkeling reef but were rare in a protected area closed to boats, which indicates that exposure of reef fauna to vessel noise will vary by reef. Temporally, vessel activity was most likely to occur during daylight hours, which is consistent with patterns of human activity. This heterogeneity in exposure could have implications for physiology and behavior and underscores the need for long-term acoustic monitoring alongside more targeted studies investigating the potential for effects of noise on aquatic organisms.

关键词：

来源：评论

学校读者我要写书评

暂无评论

APPROXIMATE LEAST SQUARES PARAMETER ESTIMATION WITH STRUCTURED OBSERVATIONS

APPROXIMATE LEAST SQUARES PARAMETER ESTIMATION WITH STRUCTUR...

引用

IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Atulya Yellepeddi James C. Preisig Electrical Eng./Applied Ocean Physics and Eng. MIT-WHOI Joint Program Applied Ocean Physics and Engineering Woods Hole Oceanographic Institution

ISBN: (纸本)9781479928941

The solution of inverse problems where the parameter being estimated has a known structure has been widely studied. In this work, we consider the situation where it is not appropriate to assume a structure for the parameter, but the observations on which the estimate are based are structured;specifically, when the observations are parametrized by a decomposable graphical model. This translates to structured sparsity of the inverse covariance matrix for Gaussian distributed observation vectors. We present an approximate least squares method which takes advantage of the structure to reduce the complexity of least squares. The approximate least squares method can be implemented recursively for even lower complexity. It is shown that the proposed method is asymptotically equivalent to least squares parameter estimation for a large number of observations. The properties of the algorithm are verified by simulation.

关键词： Least squares method variance covariance matrix Asymptotically equivalent Inverse method Parameter estimation Approximate

来源：评论

学校读者我要写书评

暂无评论

Tracking Ocean Fronts with Multiple Vehicles and Mixed Communication Losses

Tracking Ocean Fronts with Multiple Vehicles and Mixed Commu...

引用

IEEE/RSJ International Conference on Intelligent Robots and Systems

作者： Brooks L. Reed Franz S. Hover the MIT/WHOI Joint Program in Oceanographic Engineering MIT Department of Mechanical Engineering

ISBN: (纸本)9781467363563

We make two contributions toward integrated monitoring over large spatial scales, with multiple collaborating vehicles. Our focus is dynamic ocean features such as fronts and plumes. To support strong networked-control designs, we first develop a clean linear time-invariant framework for tracking features, that directly couples the global structure of the process to vehicle positioning. To address the packet loss inherent in underwater acoustic communications, we then extend the synthesis technique of Imer et al. [1] to the case where measurements and control commands suffer loss with differing statistics among the multiple channels. Simulations show that the integrated feedback system achieves good performance in front tracking.

关键词： Tracking Ocean Fronts Multiple Vehicles Mixed Communication Losses

来源：评论

学校读者我要写书评

暂无评论

DESIGN OF DECISION DEVICE FOR THE ADAPTATION OF DECISION DIRECTED EQUALIZERS

DESIGN OF DECISION DEVICE FOR THE ADAPTATION OF DECISION DIR...

引用

IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： Atulya Yellepeddi James C. Preisig Electrical Eng./Applied Ocean Physics and Eng. MIT-WHOI Joint Program Applied Ocean Physics and Engineering Woods Hole Oceanographic Institution

ISBN: (纸本)9781479903573

Adaptation of the coefficients of an equalizer usually takes place in the decision directed mode. The decision used for adaptation has a profound influence on the performance of the equalizer. In this work, we consider the influence of the probabilistic model used by a soft information decision device on the performance of the equalizer. It is shown that the equalizer output is distributed as a Gaussian Mixture, and these statistics are used to form a soft-decision device. We show that this is very near optimal in the sense of the Recursive Expected Least Squares algorithm introduced in prior work. Sub-optimal decision devices that are often more practical are also introduced and the loss of performance as a result of using these is considered.

关键词： Equalizers adaptive signal processing adaptive equalizers time-varying channels

来源：评论

学校读者我要写书评

暂无评论

Experiments in dynamic control of autonomous marine vehicles using acoustic modems

Experiments in dynamic control of autonomous marine vehicles...

引用

IEEE International Conference on Robotics and Automation (ICRA)

作者： Eric Gilbertson Brooks L. Reed Josh Leighton Mei Yi Cheung Franz S. Hover Department of Mechanical Engineering Massachusetts Institute of Technology USA WHOI Joint Program in Oceanographic Engineering Massachusetts Institute of Technology USA

ISBN: (纸本)9781467356404

Marine robots are an increasingly attractive means for observing and monitoring in the ocean, but underwater acoustic communication (“acomms”) remains a major challenge, especially for real-time control. Packet loss occurs widely, bit rates are low, and there are significant delays. We consider here strategies for feedback control with acomms links in either the sensor-controller channel, or the controller-actuator channel. On the controller-actuator side we implement sparse packetized predictive control (S-PPC), which simultaneously addresses packet-loss and the data rate limit. For the sensor-controller channel we study a modified information filter (MIF) in a Linear Quadratic Gaussian (LQG) control scheme. Field experiments were carried out with both approaches, regulating crosstrack error in a robotic kayak using acomms. Outcomes with both the S-PPC and MIF LQG confirm that good performance is achievable.

关键词： Acoustics Packet loss Sensors Delays Vehicles Trajectory

来源：评论

学校读者我要写书评

暂无评论

Robust Minimum Energy Wireless Routing for Underwater Acoustic Communication Networks

Robust Minimum Energy Wireless Routing for Underwater Acoust...

引用

Institute of Electrical and Electronics Engineers Globecom Workshops

作者： Brooks L. Reed Milica Stojanovic Urbashi mitra Franz S. Hover MIT/WHOI Joint Program in Oceanographic Engineering Northeastern University Department of Electrical Engineering University of Southern California Department of Electrical Engineering and Computer Science MIT Department of Mechanical Engineering

ISBN: (纸本)9781467349420

Marine robots are an increasingly attractive means for observing and monitoring the ocean, but underwater acoustic communications remain a major challenge. The channel exhibits long delay spreads with frequency-dependent attenuation;moreover, it is time-varying. We consider the minimum energy wireless transmission problem [MET], augmented by the practical condition that constraints on link power must be satisfied in probability. For this, we formulate the robust counterpart of the multicommodity mixed-integer linear programming (MDLP) model from Haugland and Yuan [1], and derive scaled power levels that account for uncertainty. Our main result is that the deterministic formulation with these scaled power levels recovers exactly the optimal robust solution in the absence of correlations, and therefore allows for efficient solution via MILP. This approach achieves significant power improvements over heuristics, and naturally lends itself to vehicle networks.

关键词： underwater acoustic communication Energy sources networks(communications) wireless power level Power (Psychology) mobile data link protocol Heuristics Vehicle Network Network routing

来源：评论

学校读者我要写书评

暂无评论

Soft-adaptive turbo equalization: Using soft information in adaptation

Soft-adaptive turbo equalization: Using soft information in ...

引用

Asilomar Conference on Signals, Systems & Computers

作者： Atulya Yellepeddi James C. Preisig Electrical Engineering/Applied Ocean Science and Engineering WHOI Joint Program MIT USA Applied Ocean Science and Engineering Woods Hole Oceanographic Institution Woods Hole MA USA

ISBN: (纸本)9781467350501

Turbo equalizers have been exploited for underwater wireless communication due to their excellent practical performance. As the equalizer is adaptive, it is possible to take advantage of the soft information available from the decoder in the adaptation process. In this paper, we consider a method to do this and compare it with the use of soft information in feedback, which is a method that has been considered in the past. Data from the KAM11 experiment demonstrates that using soft information in adaptation can improve performance over using it only in feedback. We also consider combining these different approaches and how this affects performance.

关键词： Using how this soft information Equalizers Worm gears Turbo CARRIER SYSTEM Feedback Equalization decoders

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：