Software

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.

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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.

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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.

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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.

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Statistical Evaluation of Utilization of the ISS

PayLoad Utilization Modeler (PLUM) is a statistical-modeling computer program used to evaluate the effectiveness of utilization of the International Space Station (ISS) in terms of the number of research facilities that can be operated within a specified interval of time. PLUM is designed to balance the requirements of research facilities aboard the ISS against the resources available on the ISS. PLUM comprises three parts: an interface for the entry of data on constraints and on required and available resources, a database that stores these data as well as the program output, and a modeler. The modeler comprises two subparts: one that generates tens of thousands of random combinations of research facilities and another that calculates the usage of resources for each of those combinations. The results of these calculations are used to generate graphical and tabular reports to determine which facilities are most likely to be operable on the ISS, to identify which ISS resources are inadequate to satisfy the demands upon them, and to generate other data useful in allocation of and planning of resources.

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Shuttle Data Center File- Processing Tool in Java

A Java-language computer program has been written to facilitate mining of data in files in the Shuttle Data Center (SDC) archives. This program can be executed on a variety of workstations or via Web-browser programs. This program is partly similar to prior C-language programs used for the same purpose, while differing from those programs in that it exploits the platform neutrality of Java in implementing several features that are important for analysis of large sets of time-series data. The program supports regular expression queries of SDC archive files, reads the files, interleaves the time-stamped samples according to a chosen output, then transforms the results into that format. A user can choose among a variety of output file formats that are useful for diverse purposes, including plotting, Markov modeling, multivariate density estimation, and wavelet multiresolution analysis, as well as for playback of data in support of simulation and testing.

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X-Windows PVT Widget Class

The X-Windows Process Validation Table (PVT) Widget Class (“Class” is used here in the object oriented programming sense of the word) was devised to simplify the task of implementing network registration services for Information Sharing Protocol (ISP) graphical user interface (GUI) computer programs. Heretofore, ISP PVT programming tasks have required many method calls to identify, query, and interpret the connections and messages exchanged between a client and a PVT server. Normally, programmers have utilized direct access to UNIX socket libraries to implement the PVT protocol queries, necessitating the use of many lines of source code to perform frequent tasks. Now, the X-Windows PVT Widget Class encapsulates ISP client server network registration management tasks within the framework of an X Windows widget. Use of the widget framework enables an X Windows GUI program to interact with PVT services in an abstract way and in the same manner as that of other graphical widgets, making it easier to program PVT clients. Wrapping the PVT services inside the widget framework enables a programmer to treat a PVT server interface as though it were a GUI. Moreover, an alternate subclass could implement another service in a widget of the same type.

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