Information Technology & Software

v-Anomica: A Fast Support Vector-Based Novelty Detection Technique

Ames Research Center, Moffett Field, California

Outlier or anomaly detection refers to the task of identifying abnormal or inconsistent patterns from a dataset. While they may seem to be undesirable entities, identifying them has many potential applications in fraud and intrusion detection, medical research, and safety-critical vehicle health management. Outliers can be detected using supervised, semi-supervised, or unsupervised techniques. Unsupervised techniques do not require labeled instances for detecting outliers. Supervised techniques require labeled instances of both normal and abnormal operation data for first building a model (e.g., a classifier), and then testing if an unknown data point is a normal one or an outlier. The model can be probabilistic such as Bayesian inference or deterministic such as decision trees, Support Vector Machines (SVMs), and neural networks. Semi-supervised techniques only require labeled instances of normal data. Hence, they are more widely applicable than the fully supervised ones. These techniques build models of normal data and then flag outliers that do not fit the model.

Posted in: Briefs, Electronics & Computers, Software, Analysis methodologies, Safety critical systems, Vehicle health management, Data management
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Self-Stabilizing Distributed Clock Synch ronization Protocol for Arbitrary Digraphs

Langley Research Center, Hampton, Virginia

A report describes a self-stabilizing distributed clock synchronization protocol in the absence of faults in the system. It is focused on the distributed clock synchronization of an arbitrary, non-partitioned digraph ranging from fully connected to 1-connected networks of nodes, while allowing for differences in the network elements. The protocol does not rely on assumptions about the initial state of the system, other than the presence of at least one node, and no central clock or a centrally generated signal, pulse, or message is used.

Posted in: Briefs, Electronics & Computers, Software, Simulation and modeling, Communication protocols
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Precision Navigation Strategies for Primitive Solar-System-Body Sample Return Missions

Goddard Space Flight Center, Greenbelt, Maryland

This project investigated advanced navigation strategies required to approach, perform proximity operations, and return a sample from an asteroid or comet. An optimized navigation strategy for a notional mission to a near-Earth asteroid was developed to serve as a baseline for future missions and mission proposals. Essential simulation and analysis software enhancements were developed and implemented in the Orbit De ter mination Toolbox (ODTBX), an open-source, early mission navigation analysis tool suite built on a flexible architecture. The development efforts of this project resulted in the first fully open-source tool suite with the capabilities of performing primitive body navigation simulation and analyses.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software, Computer software and hardware, Spacecraft guidance
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Orbit Determination Toolbox 2012a (v5.0)

Goddard Space Flight Center, Greenbelt, Maryland

The Orbit Determination Toolbox (ODTBX) 2012a (v5.0) is an advanced mission simulation and analysis tool used for concept exploration, proposal, early design phase, or rapid design center environments: the emphasis is on flexibility, but it has enough fidelity to produce credible results. ODTBX v5.0 includes multiple feature additions, enhancements, and bug fixes from the prior release (v4.5). The primary user interface and supporting functions are written in Matlab and Java.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software, Computer software and hardware, Spacecraft guidance
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Design and Construction of Protograph-Based LDPC Codes

This innovation can be used in magnetic tape recording and other channels with finite-state representation.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Writing (recording) to a storage device and reading from it can be considered as a noisy channel. A storage device such as magnetic recoding and optical recording can be modeled as a partial response channel. Partial-response techniques are a special case of precoding technique where the intersymbol interference is forced to some known pattern. Thus, read-back data from storage devices may have intersymbol interference.

Posted in: Briefs, Electronics & Computers, Information Sciences, Software, Optics, Data management, Storage
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Spitzer Integrated Resource Planning and Scheduling System (SIRPASS)

NASA’s Jet Propulsion Laboratory, Pasadena, California

This decision support system provides an integrated platform for assessing the quality of Spitzer scheduling options. The application aids in scheduling instrument selection, assigns schedule times to specific observation requests, and generates stored sequence products destined for execution on the Spitzer Space Telescope.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software, Computer software and hardware, Spacecraft
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Tracking a Scene on Earth from Space Using the Adaptive Cross-Correlation Algorithm

NASA’s Jet Propulsion Laboratory, Pasadena, California

A software program enables a user to track a scene or a spot on Earth from space (such as from the ISS) using an innovative algorithm. This robust and highly accurate software allows a scene to be tracked that can be not only the shifted version of a previous scene, but can also be a distorted one.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software, Mathematical models, Computer software and hardware, Imaging and visualization
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Automated Scheduling of Personnel to Staff Operations for the Mars Science Laboratory

NASA’s Jet Propulsion Laboratory, Pasadena, California

The task of producing Mars Science Laboratory (MSL) personnel schedules is daunting. Through automation, the labor and number of mistakes made are reduced when compared to the manual process. This software not only allows for common constraints to be expressed, but also for these to be gracefully descoped in case a solution cannot be found, thus making this unique in the personnel scheduling arena.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software, Computer software and hardware
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Area Coverage Path Planning Using Divided Grid-Graphs

NASA’s Jet Propulsion Laboratory, Pasadena, California

Planning area coverage observations is a challenge in an architecture with a framing imager affixed to a bus that can be moved, and a mirror or other device that allows for small, but fast, observation of adjacent areas along the boresight of a telescope. The telescope boresight can slew slowly while the mirror system maintains pointing on a specific field of view. This allows the continuous gathering of data (much like push - broom instruments) without the need to slew or settle. Since the telescope field of view is much larger than the imager field of view, the areas to be imaged can be divided into quarters.

Posted in: Briefs, TSP, Electronics & Computers, Information Sciences, Software, Architecture, Imaging and visualization, Data acquisition, Data acquisition (obsolete)
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Shape Sensing Using Multicore Fiber Optic Cable and Parametric Curve Solutions

Langley Research Center, Hampton, Virginia

Apaper reports a method of converting distributed curvature measurements into a three-dimensional shape by combining elastic rod theory and differential geometry to arrive at a three-dimensional solution of the Frenet-Serret formulas. A new method of calculating the shape of a multicore fiber optic cable is presented. The method utilizes discrete strain measurements obtained in each core to create a continuous representation of fiber curvature and torsion. The Frenet-Serret equations are then solved using these representations to obtain fiber shape. Shape measurements were found to have, at most, 7.2% error. The primary source of error is most likely externally induced twisting in the fiber.

Posted in: Briefs, Electronics & Computers, Software, Optics
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