Information Technology & Software

Integrated Planning for Telepresence With Time Delays

An artificial-intelligence assistant helps a human supervisor control a distant robot.

A conceptual “intelligent assistant” and an artificial-intelligence computer program that implements the intelligent assistant have been developed to improve control exerted by a human supervisor over a robot that is so distant that communication between the human and the robot involves significant signal-propagation delays. The goal of the effort is not only to help the human supervisor monitor and control the state of the robot, but also to improve the efficiency of the robot by allowing the supervisor to “work ahead.” The intelligent assistant is an integrated combination of an artificial-intelligence planner and a monitor of states of both the human supervisor and the remote robot. The novelty of the system lies in the way it uses the planner to reason about the states at both ends of the time delay.

Posted in: Briefs, Information Sciences, Artificial intelligence, Computer software and hardware, Human machine interface (HMI), Robotics

Gaussian and Lognormal Models of Hurricane Gust Factors

A document describes a tool that predicts the likelihood of land-falling tropical storms and hurricanes exceeding specified peak speeds, given the mean wind speed at various heights of up to 500 feet (150 meters) above ground level. Empirical models to calculate mean and standard deviation of the gust factor as a function of height and mean wind speed were developed in Excel based on data from previous hurricanes. Separate models were developed for Gaussian and offset lognormal distributions for the gust factor. Rather than forecasting a single, specific peak wind speed, this tool provides a probability of exceeding a specified value. This probability is provided as a function of height, allowing it to be applied at a height appropriate for tall structures.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Weather and climate

Aligning a Receiving Antenna Array To Reduce Interference

This arraying algorithm has potential utility in radio astronomy and radio communication.

A digital signal-processing algorithm has been devised as a means of aligning (as defined below) the outputs of multiple receiving radio antennas in a large array for the purpose of receiving a desired weak signal transmitted by a single distant source in the presence of an interfering signal that (1) originates at another source lying within the antenna beam and (2) occupies a frequency band significantly wider than that of the desired signal. In the original intended application of the algorithm, the desired weak signal is a spacecraft telemetry signal, the antennas are spacecraft-tracking antennas in NASA’s Deep Space Network, and the source of the wide-band interfering signal is typically a radio galaxy or a planet that lies along or near the line of sight to the spacecraft. The algorithm could also afford the ability to discriminate between desired narrow-band and nearby undesired wide-band sources in related applications that include satellite and terrestrial radio communications and radio astronomy.

Posted in: Briefs, Information Sciences, Mathematical models, Antennas

Algorithm for Detecting a Bright Spot in an Image

Corrections for background intensity and dark current are included.

An algorithm processes the pixel intensities of a digitized image to detect and locate a circular bright spot, the approximate size of which is known in advance. The algorithm is used to find images of the Sun in cameras aboard the Mars Exploration Rovers. (The images are used in estimating orientations of the Rovers relative to the direction to the Sun.) The algorithm can also be adapted to tracking of circular shaped bright targets in other diverse applications.

Posted in: Briefs, Information Sciences, Mathematical models, Imaging and visualization, Sun and solar

Extreme Programming: Maestro Style

Modifications have been made to suit a specific development environment.

“Extreme Programming: Maestro Style” is the name of a computer-programming methodology that has evolved as a custom version of a methodology, called “extreme programming” that has been practiced in the software industry since the late 1990s. The name of this version reflects its origin in the work of the Maestro team at NASA’s Jet Propulsion Laboratory that develops software for Mars exploration missions.

Posted in: Briefs, Information Sciences, Design processes, Computer software and hardware, Product development

Adaptive Behavior for Mobile Robots

A robotic system attempts to both preserve itself and progress toward a goal.

The term “System for Mobility and Access to Rough Terrain” (SMART) denotes a theoretical framework, a control architecture, and an algorithm that implements the framework and architecture, for enabling a land-mobile robot to adapt to changing conditions. SMART is intended to enable the robot to recognize adverse terrain conditions beyond its optimal operational envelope, and, in response, to intelligently reconfigure itself (e.g., adjust suspension heights or baseline distances between suspension points) or adapt its driving techniques (e.g., engage in a crabbing motion as a switchback technique for ascending steep terrain). Conceived for original application aboard Mars rovers and similar autonomous or semi-autonomous mobile robots used in exploration of remote planets, SMART could also be applied to autonomous terrestrial vehicles to be used for search, rescue, and/or exploration on rough terrain.

Posted in: Briefs, Information Sciences, Mathematical models, Adaptive control, Architecture, Terrain, Robotics

Protocol for Communication Networking for Formation Flying

This protocol provides for adaptation to changing formation geometry and communication requirements.

An application-layer protocol and a network architecture have been proposed for data communications among multiple autonomous spacecraft that are required to fly in a precise formation in order to perform scientific observations. The protocol could also be applied to other autonomous vehicles operating in formation, including robotic aircraft, robotic land vehicles, and robotic underwater vehicles.

Posted in: Briefs, Information Sciences, Architecture, Data exchange, Vehicle networking, Spacecraft

Planning Complex Sequences Using Compressed Representations

Computation time and memory needed to generate schedules are greatly reduced.

A method that notably includes the use of compressed representations interleaved with non-compressed (time-line) representations of a general scheduling problem has been conceived as a means of increasing, by orders of magnitude, the speeds of computations needed for scheduling complex sequences of activities that include cycles wherein subsets of the activities and/or sequences are repeated. The method was originally intended to be used in scheduling large campaigns of scientific observations by instruments aboard a spacecraft. A typical such campaign could include observations of millions of targets, many observations to be made during long repeated passes. The method would also be useful on Earth for scheduling complex sequences of activities that include cycles.

The method is best summarized in the context of the original intended application, wherein the scheduling problem is formulated as that of selecting, from a candidate set of observations, those observations that cover as many target points as possible without oversubscribing energy and memory budgets. Inasmuch as observation opportunities repeat, the theoretical framework for evaluation of candidate solutions includes a cycle bound.

Posted in: Briefs, Information Sciences, Mathematical models, Logistics, Test procedures

Self-Supervised Learning of Terrain Traversability From Proprioceptive Sensors

This system enables a vehicle to scan its surroundings and adapt to conditions by learning about them on the fly.

Robust and reliable autonomous navigation in unstructured, off-road terrain is a critical element in making unmanned ground vehicles a reality. Existing approaches tend to rely on evaluating the traversability of terrain based on fixed parameters obtained via testing in specific environments. This results in a system that handles the terrain well that it trained in, but is unable to process terrain outside its test parameters.

Posted in: Briefs, Information Sciences, Artificial intelligence, Sensors and actuators, Terrain, Autonomous vehicles

A Software Rejuvenation Framework for Distributed Computing

This framework supports graceful degradation of services at best possible performance levels.

A performability-oriented conceptual framework for software rejuvenation has been constructed as a means of increasing levels of reliability and performance in distributed stateful computing. As used here, “performability-oriented” signifies that the construction of the framework is guided by the concept of analyzing the ability of a given computing system to deliver services with gracefully degradable performance. The framework is especially intended to support applications that involve stateful replicas of server computers.

Posted in: Briefs, Information Sciences, Mathematical models, Architecture, Computer software and hardware, Performance upgrades

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