614 research outputs found

    An experiment with RTEMS

    Get PDF
    The Real-Time Executive for Multiprocessor Systems (RTEMS) is an open source real-time executive used in many embedded systems. This report describes our effort to gain hands-on experience with RTEMS and provides instructions on how to build and use RTEMS in two different operating environments.Approved for public release; distribution is unlimited

    Automated Mobile System for Accurate Outdoor Tree Crop Enumeration Using an Uncalibrated Camera.

    Get PDF
    This paper demonstrates an automated computer vision system for outdoor tree crop enumeration in a seedling nursery. The complete system incorporates both hardware components (including an embedded microcontroller, an odometry encoder, and an uncalibrated digital color camera) and software algorithms (including microcontroller algorithms and the proposed algorithm for tree crop enumeration) required to obtain robust performance in a natural outdoor environment. The enumeration system uses a three-step image analysis process based upon: (1) an orthographic plant projection method integrating a perspective transform with automatic parameter estimation; (2) a plant counting method based on projection histograms; and (3) a double-counting avoidance method based on a homography transform. Experimental results demonstrate the ability to count large numbers of plants automatically with no human effort. Results show that, for tree seedlings having a height up to 40 cm and a within-row tree spacing of approximately 10 cm, the algorithms successfully estimated the number of plants with an average accuracy of 95.2% for trees within a single image and 98% for counting of the whole plant population in a large sequence of images

    MYSEA Testbed

    Get PDF
    The technical vision of the emerging net-centric Global Information Grid (GIG) encompasses support for high assurance authentication and multilevel security (MLS) as well as flexible, dynamic security policies. The GIG is intended to address the inefficient exchange of information in current military and intelligence operations that utilize a variety of specialized (so-called "stove-piped") systems. In this context, secure information access problems are exacerbated by the need to share information from networks at different classifications (e.g., Unclassified, Secret, and Top Secret) and within multinational coalitions in episodic, ad hoc situations. These challenges provide the impetus for the creation of the Monterey Security Architecture (MYSEA) Testbed. The purpose of this Testbed is to support research in high assurance multilevel security (MLS) [1, 2] and dynamic security, two areas that are critical to the realization of the GIG's assured information sharing vision.Approved for public release; distribution is unlimited

    Impacts of State Reopening Policy on Human Mobility

    Get PDF
    This study quantifies the effect of state reopening policies on daily mobility, travel, and mixing behavior during the COVID-19 pandemic. We harness cell device signal data to examine the effects of the timing and pace of reopening plans in different states. We quantify the increase in mobility patterns during the reopening phase by a broad range of cell-device-based metrics. Soon (four days) after reopening, we observe a 6% to 8% mobility increase. In addition, we find that temperature and precipitation are strongly associated with increased mobility across counties. The mobility measures that reflect visits to a greater variety of locations responds the most to reopening policies, while total time in vs. outside the house remains unchanged. The largest increases in mobility occur in states that were late adopters of closure measures, suggesting that closure policies may have represented more of a binding constraint in those states. Together, these four observations provide an assessment of the extent to which people in the U.S. are resuming movement and physical proximity as the COVID-19 pandemic continues

    A Linux Implementation of Temporal Access Controls

    Full text link
    Abstract — Control of access to information based upon temporal attributes can add another dimension to access control. To demonstrate the feasibility of operating system-level support for temporal access controls, the Time Interval File Protection System (TIFPS), a prototype of the Time In-terval Access Control (TIAC) model, has been implemented by modifying Linux extended attributes to include temporal metadata associated both with files and users. The Linux Security Module was used to provide hooks for temporal ac-cess control logic. In addition, a set of utilities was modified to be TIFPS-aware. These tools permit users to view and manage the temporal attributes associated with their files and directories. Functional, performance, and concurrency testing were conducted. The ability of TIFPS to grant or revoke access in the future, as well to limit access to specific time intervals enhances traditional information control and sharing. I

    An Experiment with CC Version 3.0 Migration

    Get PDF
    7th International Common Criteria Conference Lanzarote, Spain September 19-21, 200

    CAFE simulation of columnar-to-equiaxed transition in Al-7wt%Si alloys directionally solidified under microgravity

    No full text
    International audienceA two-dimensional multi-scale cellular automaton - finite element (CAFE) model is used to simulate grain structure evolution and microsegregation formation during solidification of refined Al-7wt%Si alloys under microgravity. The CAFE simulations are first qualitatively compared with the benchmark experimental data under microgravity. Qualitative agreement is obtained for the position of columnar to equiaxed transition (CET) and the CET transition mode (sharp or progressive). Further comparisons of the distributions of grain elongation factor and equivalent diameter are conducted and reveal a fair quantitative agreement
    • …
    corecore