Coastal Ocean Modeling and Observation Program: Real-time Adaptive Sampling Networks

1999 ◽  
Author(s):  
Scott M. Glenn ◽  
Dale B. Haidvogel ◽  
Oscar M. Schofield
Keyword(s):  
Real Time ◽  
Adaptive Sampling ◽  
Coastal Ocean ◽  
Ocean Modeling ◽  
Observation Program

Coastal Ocean Modeling and Observation Program

2002 ◽  
Author(s):  
Scott Glenn ◽  
Dale Haidvogel ◽  
Oscar Schofield ◽  
John Wilkin
Keyword(s):  
Coastal Ocean ◽  
Ocean Modeling ◽  
Observation Program

scholarly journals Coastal Ocean Modeling: Processes and Real-Time Systems

Oceanography ◽  
2000 ◽  
Vol 13 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Dale Haidvogel ◽  
Blanton ◽  
Kindle ◽  
Lynch
Keyword(s):  
Real Time ◽  
Coastal Ocean ◽  
Modeling Processes ◽  
Ocean Modeling ◽  
Real Time Systems ◽  
Time Systems

Coastal Ocean Modeling and Observation Program (COMOP-II)

2001 ◽  
Author(s):  
Scott M. Glenn ◽  
Dale B. Haidvogel ◽  
Oscar M. Schofield ◽  
John Wilkin
Keyword(s):  
Coastal Ocean ◽  
Ocean Modeling ◽  
Observation Program

scholarly journals Networked Acoustic Modems for Real-Time Data Telemetry from Distributed Subsurface Instruments in the Coastal Ocean: Application to Array of Bottom-Mounted ADCPs

2005 ◽  
Vol 22 (6) ◽  
pp. 704-720 ◽  
Author(s):  
Daniel L. Codiga ◽  
Joseph A. Rice ◽  
Paul A. Baxley ◽  
David Hebert
Keyword(s):  
New York ◽  
Real Time ◽  
Adaptive Sampling ◽  
Coastal Ocean ◽  
Network Control ◽  
Wireless Data ◽  
Time Data ◽  
Strong Winds ◽  
Handshake Protocol ◽  
Acoustic Modem

Abstract Through the winter and spring of 2002, networked acoustic modems demonstrated real-time wireless data telemetry from an array of bottom-mounted acoustic Doppler current profilers (ADCPs) on the inner continental shelf 20–60 m deep off of Montauk Point, New York. To achieve typical temporal and spatial sampling needs for data assimilative numerical modeling, the array spanned 10 km × 10 km and transmitted data each ∼2 h. Network nodes included five sensors, each an ADCP with acoustic modem housed in a trawl-resistant bottom frame; five repeaters that are individual acoustic modems on near-bottom taut-wire moorings; and two gateways, each a buoy with a subsurface acoustic modem and topside cellular modem allowing for two-way communication with the shore. Deliveries from an ADCP adjacent to the gateway buoy were more than 97% successful through both winter and spring. Deliveries from ADCPs 5 km from the gateway averaged 25% (86%) reliability in winter (spring). Winter performance degrades because of upward-refracting sound speed profiles that limit direct acoustic paths, and strong winds that disrupt sea surface reflectivity and increase ambient noise. Reliability improved up to 36% due to the receive-all gateway mode, and more than doubled for certain node pairs due to a handshake protocol incorporating an automatic repeat request. Shore-based network control demonstrated adaptive sampling by changing ADCP vertical and temporal resolution, and network data path rerouting in response to unplanned events, such as trawling impacts. Networked acoustic modems are well suited for coastal ocean-observing systems, particularly at sites such as this where seafloor cables and surface buoys are vulnerable to fishing and shipping activities.

Real-time subsurface scattering with single pass variance-guided adaptive importance sampling

2020 ◽  
Vol 3 (1) ◽  
pp. 1-21
Author(s):  
Tiantian Xie ◽  
Marc Olano ◽  
Brian Karis ◽  
Krzysztof Narkowicz
Keyword(s):  
Real Time ◽  
Adaptive Sampling ◽  
Monte Carlo Sampling ◽  
Diffusion Profile ◽  
Correct Result ◽  
Subsurface Scattering ◽  
Stochastic Sampling ◽  
Light Gradient ◽  
Temporal Variance ◽  
Importance Function

In real-time applications, it is difficult to simulate realistic subsurface scattering with differing degrees translucency. Burley's reflectance approximation by empirically fitting the diffusion profile as a whole makes it possible to achieve realistic looking subsurface scattering for different translucent materials in screen space. However, achieving a physically correct result requires real-time Monte Carlo sampling of the analytic importance function per pixel per frame, which seems prohibitive to achieve. In this paper, we propose an approximation of the importance function that can be evaluated in real-time. Since subsurface scattering is more pronounced in certain regions (e.g., with light gradient change), we propose an adaptive sampling method based on temporal variance to lower the required number of samples. We propose a one phase adaptive sampling pass that is unbiased, and able to adapt to scene changes due to motion and lighting. To further improve the quality, we explore temporal reuse with a guiding pass prior to the final temporal anti-aliasing (TAA) phase that further improves the quality. Our local guiding pass does not constrain the TAA implementation, and only requires one additional texture to be passed between frames. Our proposed variance-guided algorithm has the potential to make stochastic sampling algorithm effective for real-time rendering.

scholarly journals Irregular Morphing for Real-Time Rendering of Large Terrain

2016 ◽  
Vol XLI-B3 ◽  
pp. 755-762 ◽  
Author(s):  
Sid'Ali Kalem ◽  
Assia Kourgli
Keyword(s):  
Real Time ◽  
Adaptive Sampling ◽  
Approximation Error ◽  
Surface Characteristics ◽  
Remote Visualization ◽  
Terrain Rendering ◽  
Real Time Processing ◽  
Tile Size ◽  
Multi Resolution Analysis ◽  
Screen Space

The following paper proposes an alternative approach to the real-time adaptive triangulation problem. A new region-based multi-resolution approach for terrain rendering is described which improves on-the-fly the distribution of the density of triangles inside the tile after selecting appropriate Level-Of-Detail by an adaptive sampling. This proposed approach organizes the heightmap into a QuadTree of tiles that are processed independently. This technique combines the benefits of both Triangular Irregular Network approach and region-based multi-resolution approach by improving the distribution of the density of triangles inside the tile. Our technique morphs the initial regular grid of the tile to deformed grid in order to minimize approximation error. The proposed technique strives to combine large tile size and real-time processing while guaranteeing an upper bound on the screen space error. Thus, this approach adapts terrain rendering process to local surface characteristics and enables on-the-fly handling of large amount of terrain data. Morphing is based-on the multi-resolution wavelet analysis. The use of the D2WT multi-resolution analysis of the terrain height-map speeds up processing and permits to satisfy an interactive terrain rendering. Tests and experiments demonstrate that Haar B-Spline wavelet, well known for its properties of localization and its compact support, is suitable for fast and accurate redistribution. Such technique could be exploited in client-server architecture for supporting interactive high-quality remote visualization of very large terrain.

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