Engineering topics

Grossman, Robert L.

Publications and source records attributed to Grossman, Robert L..

9 records

NASA NTRS2016

The Matsu Wheel: A Cloud-Based Framework for Efficient Analysis and Reanalysis of Earth Satellite Imagery

Project Matsu is a collaboration between the Open Commons Consortium and NASA focused on developing open source technology for cloud-based processing of Earth satellite imagery with practical applications to aid in natural disaster detection and relief. Project Matsu has developed an open source cloud-based infrastructure to process, analyze, and reanalyze large collections of hyperspectral satellite image data using OpenStack, Hadoop, MapReduce and related technologies. We describe a framework for efficient analysis of large amounts of data called the Matsu "Wheel." The Matsu Wheel is currently used to process incoming hyperspectral satellite data produced daily by NASA's Earth Observing-1 (EO-1) satellite. The framework allows batches of analytics, scanning for new data, to be applied to data as it flows in. In the Matsu Wheel, the data only need to be accessed and preprocessed once, regardless of the number or types of analytics, which can easily be slotted into the existing framework. The Matsu Wheel system provides a significantly more efficient use of computational resources over alternative methods when the data are large, have high-volume throughput, may require heavy preprocessing, and are typically used for many types of analysis. We also describe our preliminary Wheel analytics, including an anomaly detector for rare spectral signatures or thermal anomalies in hyperspectral data and a land cover classifier that can be used for water and flood detection. Each of these analytics can generate visual reports accessible via the web for the public and interested decision makers. The result products of the analytics are also made accessible through an Open Geospatial Compliant (OGC)-compliant Web Map Service (WMS) for further distribution. The Matsu Wheel allows many shared data services to be performed together to efficiently use resources for processing hyperspectral satellite image data and other, e.g., large environmental datasets that may be analyzed for many purposes.

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NASA NTRS1996

A Note on Interfacing Object Warehouses and Mass Storage Systems for Data Mining Applications

Data mining is the automatic discovery of patterns, associations, and anomalies in data sets. Data mining requires numerically and statistically intensive queries. Our assumption is that data mining requires a specialized data management infrastructure to support the aforementioned intensive queries, but because of the sizes of data involved, this infrastructure is layered over a hierarchical storage system. In this paper, we discuss the architecture of a system which is layered for modularity, but exploits specialized lightweight services to maintain efficiency. Rather than use a full functioned database for example, we use light weight object services specialized for data mining. We propose using information repositories between layers so that components on either side of the layer can access information in the repositories to assist in making decisions about data layout, the caching and migration of data, the scheduling of queries, and related matters.

Grossman, Robert L.↗

NASA NTRS1993

Path planning by querying persistent stores of trajectory segments

We introduce an algorithm for path planning (long duration) paths of dynamical systems, given a persistent object store containing suitable collections of short duration trajectory segments. We also describe experimental results from a proof-of-concept implementation of the algorithm. The basic idea is to interpret a path planning algorithm as a suitable query on a persistent object store consisting of short duration trajectory segments. The query returns a concatenation of short duration trajectory segments which is close to the desired path. The needed short duration segments are computed by using a divide and conquer algorithm to break up the original path into shorter paths; each shorter path is then matched to a nearby trajectory segment which is part of the persistent object store by using a suitable index function.

Grossman, Robert L.↗

NASA NTRS1992

Convective boundary layer budgets of moisture and sensible heat over an unstressed prairie

An evaluation of convective boundary layer budgets of sensible heat and moisture were examined for two days over the unstressed vegetation of the tallgrass Konza National Prairie. In addition to the budget evaluation the study had these goals: to estimate the area-average surface fluxes and compare them to independent, ground-based measurements, to estimate the near surface evaporative fraction, and to compare different evaluations of the ratio of surface to inversion fluxes, i.e., the entrainment parameter. The budget analyses indicate that vertical and horizontal advection were significant terms in the budget and cannot be ignored.

Grossman, Robert L.↗

NASA NTRS1992

Sampling errors in the vertical fluxes of potential temperature and moisture measured by aircraft during FIFE

This paper contributes to understanding the particular problems encountered during FIFE 87 as a result of utilizing relatively short (15 km) averaging lengths for the flux estimates. The implications of employing data that had been high-pass filtered with a five-km cutoff wavelength for flux estimates are also investigated. It is found that a 15-km run length is just adequate for low-level flux estimates as long as the runs are crosswind.

Grossman, Robert L.↗

NASA NTRS1990

The distribution of deep convection over ocean and land during the Asian summer monsoon

The characteristics of the convection over the summer monsoon are investigated using the highly reflective cloud (HRC) data set (which is a subjective-analyzed daily index of organized deep convection, at one degree resolution, for years between 1971 and 1988 of the polar-orbiting satellite imagery). The results of the analysis are used to obtain the geographical distribution of HRCs for the climatological mean summer monsoon season and its four component months and to examine the intraseasonal variation of convection over selected areas. The model results of Webster and Chou (1980) are tested by comparing the relative frequency of occurrence of HRC for continental areas, coastal zones, and open ocean.

Grossman, Robert L.↗

NASA NTRS1990

Air-sea interaction during an extreme cold air outbreak from the eastern coast of the United States

An aircraft investigation of boundary layer mean and turbulent structure is reported, and the Lagrangian budgets of temperature and moisture in the subcloud layer following a streamline during an extreme cold air outbreak are evaluated. The maximum sea-air temperature difference was 23 K. Two aircraft were used: the NCAR Electra, which measured turbulent fluxes and investigated subcloud layer conditions, and the NASA Electra, which measured the height of cloud tops using lidar. A stratocumulus overcast was found from about 60 km offshore to the Gulf Stream core with cloud top rising downstream. East of the Gulf Stream cumulus congestus and snow showers were observed. Cloud base decreased downstream and numerous steam plumes filled the subcloud layer. Temperature cross sections show most warming, and moistening of the subcloud layer occurred before the Gulf Stream core. Windspeeds increased downstream and maxima were observed near cloud top (inversion) and in the subcloud layer. Lagrangian budgets showed most warming, and moistening of the layer between 70 m and about 100 m below mean cloud base was due to turbulent flux divergence.

Grossman, Robert L.↗

NASA NTRS1990

Temporal variation of heat and moisture flux divergence in the FIFE atmospheric boundary layer during spring

A one-day investigation of the atmospheric boundary layer (ABL) is reported in which an aircraft monitors the temporal and spatial variations of heat and moisture turbulent-flux divergences. Incoming solar radiation is similar over natural prairie land and agriculturally developed land although the heat and moisture values show significant differences over the surfaces. Other temporal variations are noted which demonstrate that ABL transport of sensible and latent heat is affected by complex variables even under simple synoptic conditions.

Grossman, Robert L.↗

NASA NTRS1988

Boundary layer warming by condensation - Air-sea interaction during an extreme cold air outbreak from the eastern coast of the United States

Studies on an intense cold air outbreak that took place after a cold air cyclogenesis on January 27, 1986 are reviewed. Particular attention is given to data obtained during a multiaircraft research mission carried out on January 28, 1986 as part of the Genesis of Atlantic Lows Experiment. It was found that condensation heating of the subcloud layer air was comparable to heating by turbulent flux divergence.

Grossman, Robert L.↗