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Framework for Flexible Security in Group Communications

The Antigone software system defines a framework for the flexible definition and implementation of security policies in group communication systems. Antigone does not dictate the available security policies, but provides high-level mechanisms for implementing them. A central element of the Antigone architecture is a suite of such mechanisms comprising micro-protocols that provide the basic services needed by secure groups. Policies are implemented through the composition and configuration of these mechanisms. Mechanisms are composed in different ways to address new requirements and environ-mental constraints. The Antigone framework provides an easy-to-use application programming interface (API), from which secure group application programs can be built. Written entirely in the C++ programming language, the system consists of over 18,000 lines of source code and has been ported to several versions of Linux, FreeBSD, and SunOS. Information for accessing recent versions of the source code and related documentation is available at http://antigone.eecs.umich.edu.

Posted in: Software, Briefs

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Integrated Modeling Environment

The Integrated Modeling Environment (IME) is a software system that establishes a centralized Web-based interface for integrating people (who may be geographically dispersed), processes, and data involved in a common engineering project. The IME includes software tools for life-cycle management, configuration management, visualization, and collaboration. It enables organized, efficient communication of engineering analyses and the statuses thereof. Key functions performed by use of the IME include creation, further development, and management of modeling analyses over their entire life cycles; publishing model and analysis information for availability and reuse throughout the user community; and managing legacy information without regard to original formats, database organizations, or computing platforms. The use of the IME creates an archive of analysis results, plus documentation that identifies the assumptions and data elements used for each analysis. This archive is configured to enable reuse of previous analysis results, and tracing of types and versions of software used for each step of each analysis. The IME utilizes a customized version of a commercial product-life-cycle-management application program that provides rich capabilities for managing configurations, workflows, data, and access through a single Web-based environment.

Posted in: Software, Briefs

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Modified Recursive Hierarchical Segmentation of Data

An algorithm and a computer program that implements the algorithm that performs recursive hierarchical segmentation (RHSEG) of data have been developed. While the current implementation is for two-dimensional data having spatial characteristics (e.g., image, spectral, or spectral-image data), the generalized algorithm also applies to three-dimensional or higher dimensional data and also to data with no spatial characteristics. The algorithm and software are modified versions of a prior RHSEG algorithm and software, the outputs of which often contain processing window artifacts including, for example, spurious segmentation-image regions along the boundaries of processing-window edges. The modification consists of the addition of an efficient subroutine through which pairs of regions are identified that may contain pixels that are actually more similar to other regions in the pair. Once these pairs of regions are identified, pixels in one region that are more similar to pixels in the other region are reassigned to the other region. The subroutine is computationally efficient because it focuses only on those regions that could potentially contribute to the processing-window artifacts. In addition, any adverse effect of the subroutine on the computational efficiency of the algorithm is minimized by executing the subroutine at a point in the algorithm such that switching of pixels between regions that are subsequently merged is avoided.

Posted in: Software, Briefs

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Software for Collaborative Use of Large Interactive Displays

The MERBoard Collaborative Workspace, which is currently being deployed to support the Mars Exploration Rover (MER) Missions, is the first instantiation of a new computing architecture designed to support collaborative and group computing using computing devices situated in NASA mission operations rooms. It is a software system for generation of large-screen interactive displays by multiple users. The architecture provides a platform and applications programming interface (API) for the development of collaborative applications for NASA mission operations. The standard deployment configuration provides an integrated whiteboard, Web browser, remote viewing and control for collaboration over distance, and personal and group storage spaces that provide ubiquitous access and sharing of data. Customization for specific domains is provided through plug-ins. For the MER mission, plug-ins include a flow-charting tool for strategic rover operations and mission planning, 3D visualization of the Martian terrain, a data navigator to navigate the mission database, and situational awareness tools. The MERBoard software is designed to run on large plasma displays with touch-screen overlays, thus providing an immersive and interactive environment for teams to view, annotate, and share data. The MERBoard overcomes the obstacles to communication, retention, and collaborative modification of information in diverse forms that can include text, data (including images) from scientific instruments, handwritten notes, hand drawings, and computer graphics. The MERBoard provides a unifying interface for the integration of heterogeneous applications, and provides those applications with a consistent model for saving and retrieving data. All applications may be viewed and controlled from any location that has a MERBoard. A personal client provides integration of a user’s personal computing environment with the MERBoard environment.

Posted in: Software, Briefs

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FETs Based on Doped Polyaniline/Polyethylene Oxide Fibers

Advantages include tailorability of electronic properties and low power demands. A family of experimental highly miniaturized field-effect transistors (FETs) is based on exploitation of the electrical properties of nanofibers of polyaniline/ polyethylene oxide (PANi/PEO) doped with camphorsulfonic acid. These polymer-based FETs have the potential for becoming building blocks of relatively inexpensive, low-voltage, high-speed logic circuits that could supplant complementary metal oxide/semiconductor (CMOS) logic circuits.

Posted in: Semiconductors & ICs, Briefs

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Theodolite Ring Lights

These lights facilitate the use of spherical tooling balls as position references. Theodolite ring lights have been invented to ease a difficulty encountered in the well-established opticalmetrology practice of using highly reflective spherical tooling balls as position references. As described in more detail below, a theodolite ring light is attached to a theodolite or telescope and used to generate a visible target on a tooling ball.

Posted in: Physical Sciences, Briefs

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Stable Satellite Orbits for Global Coverage of the Moon

A document proposes a constellation of spacecraft to be placed in orbit around the Moon to provide navigation and communication services with global coverage required for exploration of the Moon. There would be six spacecraft in inclined elliptical orbits: three in each of two orthogonal orbital planes, suggestive of a linked-chain configuration. The orbits have been chosen to (1) provide 99.999-percent global coverage for ten years and (2) to be stable under perturbation by Earth gravitation and solar-radiation pressure, so that no deterministic firing of thrusters would be needed to maintain the orbits. However, a minor amount of orbit control might be needed to correct for such unmodeled effects as outgassing of the spacecraft.

Posted in: Mechanical Components, Briefs

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