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  • Analysis of ERS use cases for iRODs

    Abstract: The purpose of this paper is to discuss the challenges inherent with High Performance Computing (HPC) data storage access and management, the capabilities of iRODS, and the analysis of several Engineered Resilient Systems (ERS) use cases relating iRODS capabilities to the teams’ stated needs. Specifically, these teams are the ERS Data Analytics group (specifically their research on rotorcraft maintenance in conjunction with the U. S. Army Aviation and Missile Research Development and Engineering Center [AMRDEC]), the ERS Environmental Simulation research team, the ERS Sensor Systems research team, and the HPC/Scientific computing group representing the “General HPC User.”
  • PUBLICATION NOTICE: Evaluating Parametric Probability Density Functions for Urban Acoustic Noise

    Abstract: This paper evaluates the suitability of three parametric probability density functions for characterizing urban acoustic noise. For that purpose, the sound levels in one-third-octave bands (6.3 Hz-20 kHz) were measured every 0.5 seconds for 5 minutes (for a total of 600 measurements) at 38 locations in Boston, USA. The probability density functions for this dataset were approximated using histograms and the log-normal, generalized gamma, and compound gamma distributions. Maximizing the log-likelihood for each distribution yielded their parameters. The suitability of each distribution was evaluated using the Kullback-Leibler divergence with the histogram approximation as the reference. Overall, the compound gamma distribution was the most accurate followed by the log-normal and then the generalized gamma distributions. Nonetheless, the simplicity of the two-parameter log-normal distribution might be preferred over the three-parameter compound the distributions of its parameters across all locations and frequencies were also approximated parametrically, which provided satisfactory agreement.
  • PUBLICATION NOTICE: Sensor and Environment Physics in the Virtual Autonomous Navigation Environment (VANE)

    Abstract: This report documents the physics models that are implemented in the Virtual Autonomous Navigation Environment (VANE), a sensor simulator that uses physics-based ray tracing to simulate common robotic sensors such as cameras, LiDAR, GPS, and automotive RADAR. The report will provide information about the underlying assumptions and implementation details regarding the physics models used in VANE simulations. These include surface reflectance and texture models, atmospheric models, weather effects, and sensor properties. The purpose of this report is to provide information for VANE users, developers, and analysts who would like to use the VANE for sensor simulations.
  • PUBLICATION NOTICE: Preliminary Measurements on the Geography of Urban VHF Radio-Frequency Noise

    Abstract: Radio-frequency (RF) noise has typically been measured at a handful of fixed, representative locations within the urban environment (Achatz, Lo, Papazian, Dalke, & Hufford, 1998; Achatz & Dalke, 2001; Dalke, Achatz, Lo, Papazian, & Hufford, 1997; Wepman & Sanders, 2011; Wagstaff & Merricks, 2005; Spaulding & Disney, 1974). In this work, we discuss the development of a mobile RF noise measurement system and the necessary geospatial and statistical post-processing techniques required to characterize the variations in noise on the street-scale in the VHF sections (60 – 300 MHz) of the spectrum. We discuss the design of our mobile noise measurement system, with special focus on the choice and calibration of preselection filters and preamplifiers necessary to reliably measure low RF noise levels while avoiding intermodulation distortion problems that arise in an environment with many strong emitters. Additionally, we describe post-processing techniques developed to reliably merge and interpolate the RF data with geolocation data which are collected on two very different (microsecond and multisecond, respectively) timescales. We use a preliminary urban dataset from Boston, MA to show that the geo-statistical properties of RF noise power can vary appreciably over street-scale distances, and that these spatial variations are repeatable over tactically relevant times.
  • PUBLICATION NOTICE: On the Use of CSHORE for Beach-fx

    Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents and documents a series of MATLAB and Python scripts that prepare, run, and process CSHORE files for use in Beach-fx. CSHORE (Johnson et al. 2012) is a one-dimensional cross-shore profile evolution model that predicts storm-induced beach profile change. Beach-fx (Gravens et al. 2007) is an engineering-economic model that computes the evolution and economic benefits associated with beach renourishment projects and requires profile erosion estimates. Historically, the crossshore profile response model SBEACH (Larson et al. 1990) has been implemented in the creation of Beach-fx studies although the Beach-fx model was designed to allow alternative profile response models, such as CSHORE, to be used.
  • PUBLICATION NOTICE: Computer-Based Calibration and Uncertainty Analysis of GenCade: Description and Proof of Concept

    Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides a description of a methodology for the computer-based calibration or Parameter Estimation (PE) and corresponding Uncertainty Analysis (UA) for the shoreline change model GenCade developed by the US Army Corps of Engineers. This work demonstrates the suitability and benefits of applying the proposed PE and UA methods to GenCade studies using an idealized case as well as a simple field study as a proof of concept. This document is primarily for engineers and decision-makers interested in the implementation of PE and UA in one-line shoreline change models such as GenCade.
  • PUBLICATION NOTICE: Contribution of Two Eroding Banks to Multipurpose Pool Sedimentation at a Midwestern Reservoir

    Abstract: This US Army Corps of Engineers (USACE) National Regional Sediment Management Technical Note (RSM-TN) documents the sediment contribution of two eroding banks to multipurpose pool sedimentation at Kanopolis Lake, KS. The analysis is based on a 2009 LIDAR and an August 2019 unmanned aircraft systems (UAS)-based structure from motion survey.
  • PUBLICATION NOTICE: Isarithmic mapping of radio-frequency noise in the urban environment

    Abstract: Radio-frequency (RF) background noise is a spatially-varying and critical parameter for predicting radio communication system and electromagnetic sensor performance in urban environments. Previous studies have measured urban RF noise at fixed, representative locations. The Cold Regions Research and Engineering Laboratory (CRREL) has developed a tunable system for conducting mobile RF noise measurements in the VHF and UHF and shown that urban RF noise characteristics vary significantly and repeatably at a scale of tens of meters (Haedrich & Breton, 2019). CRREL also found high-powered regions in Boston, MA that are persistent over time. However, since previous studies conducted stationary measurements or measurements along linear transects, little is known about the 2-dimensional topography of urban noise and the spatial distribution and characteristics of these high-powered regions. In this paper, we present the results of a dense, block-grid survey of downtown Boston, MA at 142 and 246.5 MHz with measurements taken every meter along each street. We present isarithmic maps of median noise power and describe the spatial distribution, shape and other characteristics of the high-powered regions. We compare the rate of noise power decay around high-powered regions to losses predicted by a power law model of path loss.
  • PUBLICATION NOTICE: Seasonal Effects on Vehicle Mobility: High-Latitude Case Study

    Abstract: Seasonality plays a key role in altering the terrain of many military operating environments. Since seasonality has such a large impact on the terrain, it needs to be properly accounted for in vehicle dynamics models. This work outlines a variety of static and dynamic seasonal terrain conditions and their impacts on vehicle mobility in an austere region of Europe. Overall the vehicles performed the best in the dry season condition. The thaw season condition had the most drastic impact on mobility with all but the heavy tracked vehicle being almost completely NOGO in the region. Overall, the heavy tracked vehicle had the best performance in all terrain conditions. These results highlight the importance of incorporating seasonal impacts on terrain into NRMM or any vehicle dynamics model. Future work will focus on collecting more data to improve the empirical relationships between vehicles and seasonal terrain conditions, thereby allowing for more accurate speed predictions.
  • PUBLICATION NOTICE: Insights: An Update of the USACE Data Strategy Initiative; November 2019 Edition

    Abstract: The Data25 strategy was advanced in FY19 by the U.S. Army Corps of Engineers’ Chief Information Officer (USACE CIO) by funding pilots to show the power of data analytics on real USACE operations. This report details pilots that were conducted in three of USACEs Business Lines; Dredging, Hydropower, and Military Construction. The purposes for each of these pilots are listed below. 1. Enterprise value: Demonstrates the power of data analytics and its ability to generate business value by improving decision-making across the organization. 2. Technology value: Helps the CIO understand how cloud technology could support the overall data strategy. 3. Business value: Provides examples of data analytics in action. This view helps the Business Lines, Divisions, and Districts understand what it takes to supplement decision-making with insights generated from data. The main purpose of the pilots was to provide a glimpse of what could be gained from data analytics. From the initial business questions, the pilot Business Lines are seeking to use data to improve decisions through the automation of business processes, more rapid decision cycles, and the layering of previously siloed data on their own to reveal new insights.