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Ensemble

Ensemble tools for different missions share a common look and feel, easing the transition of personnel between projects. NASA’s Jet Propulsion Laboratory, Pasadena, California Success in mission operations relies on achieving consensus amongst a wide variety of personnel with diverse backgrounds and education. Previously, NASA missions relied on disparate tools with a variety of inconsistent interfaces. These tools greatly influence how members of the mission communicate with each other, increasing confusion and reducing consensus. Ensemble provides a shared interface that helps scientists and engineers of differing disciplines to collaborate effectively. Within a single tool, Ensemble allows scientists and engineers to efficiently discuss objectives and understand the tradeoffs between exploration and discovery.

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SIVO-PyD: A Python Distribution for Scientific Computing Visualization

Goddard Space Flight Center, Greenbelt, Maryland SIVO-PyD gathers and automatically installs (in various computing platforms) a collection of Python-related packages for scientific computing and visualization. All of the packages in distribution are accessible within the Python framework. The distribution is self-contained and can be extended with minimal work.

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Spherical Empirical Mode Decomposition

Goddard Space Flight Center, Greenbelt, Maryland The spherical empirical mode decomposition algorithm is an adaptation in the spherical space of the 2D empirical mode decomposition in Euclidian space. This algorithm is a signal analysis method for any spherical data, such as orbital measurements. The two primary advantages of this innovation are the absence of edge effects in the results, and the computational efficiency of the processing.

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Database Design for Storing Software Entity Metadata, User Identification, and License Terms

NASA’s Jet Propulsion Laboratory, Pasadena, California The NASA Space Telecommunications Radio System (STRS) specification cites a plan for an application repository, similar to an “app store,” but with a wide variety of licensing restrictions on access to different applications, and even different parts of an application package (for instance, wide access to descriptive documentation but limited access to source code). A method is needed to coordinate application artifact storage, license terms, and user access rights.

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Development of Free Molecule Flow Equations from a Transient, Asymmetric Source

Molecular flow model is explored as a tool to describe an unusual variety of plume interaction issues. Goddard Space Flight Center, Greenbelt, Maryland The analysis and simulation of gases expanding from sources such as rocket nozzles into vacuum, or the effects plumes from these sources create when they interact with solid surfaces, present a considerable challenge to the scientific and engineering communities. As a plume expands into vacuum, density levels, and hence collision rates, decrease rapidly by many orders of magnitude. The main difficulty lies in accurately describing a flow field extending from continuum flow at the nozzle exit, through the transition regime, and reaching free molecule behavior within a relatively short distance downstream. For thrusters, flow at the nozzle exit is usually characterized by high exit velocities and relatively high Mach numbers. Even in regions where significant intermolecular collision rates occur, relative velocity levels are low, and little thermal scattering occurs normal to the mainly radial streamlines. Such observations lead one to consider describing the expansion under certain circumstances using free molecule theory.

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Formal Validation of Model-Based Fault Management Design Solutions

A number of advantages of modeling fault protection logical design, executing the model, and running a model checker are identified. NASA’s Jet Propulsion Laboratory, Pasadena, California Model-Based System Engineering is becoming widely adopted at JPL and in industry because model-centric systems introduce improved methods of system engineering. As systems with ever-increasing complexity are developed at JPL, model-centric engineering be comes essential for design, test, and validation. Validation of FP designs is historically problematic, with many examples of inadequate resources (people, time, and budget) and/or unexpected problems. Many factors contribute to these issues, but the problem can be traced to a lack of appreciation of system complexity. When considering a system, there are significantly more ways the system can fail (contingency paths) than ways it can succeed (nominal paths). As NASA continues to develop more complex and capable spacecraft, the behavior state space will increase, stressing the ability of teams to properly understand system behavior.

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Fast Block Transforms on Large Binary Datasets in the Cloud Using Hadoop Streaming

NASA’s Jet Propulsion Laboratory, Pasadena, California A software framework on top of Hadoop Streaming enables both the processing of binary data in the cloud, and the freedom for the developer to implement his or her mapper and reducer programs in any language, rather than re-implementing existing solutions in Java, or repackaging existing binary data into a text format. Binary data is partitioned into chunks that are kept in a persistent data storage medium. A textual list of filenames for these chunks is piped into a Hadoop Streaming mapper program, which then reads the corresponding files, computes block transforms locally, and writes the results back to persistent data storage. The mapper program is stored on all compute nodes, and the filenames are distributed in parallel across the cluster, so that the workload is evenly distributed and the end-to-end block transform speedup is roughly given by the number of nodes in the cluster.

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