Information Science

Multi-Scale Model of Failure in a Composite Material

An adaptive concurrent multilevel computational model of failure in a heterogeneous-material structure has been developed. As used here, "concurrent" is a term of art characterizing a class of structural/material models that (1) incorporate submodels representing material substructures at different spatial scales from macroscopic to microscopic, (2) the equations of the various models are solved simultaneously, and (3) the solutions at the various scales are coupled. The present model applies, more specifically, to a unidirectionalfiber/ matrix composite material structure. The model can be used to simulate and analyze the initiation and growth of damage, starting from microstructural damage in the form of debonding at fiber/matrix interfaces.

Posted in: Briefs, Information Technology, Failure analysis, Simulation and modeling, Composite materials
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Two-Processor Autopilot System for a UAV

Atwo-processor autopilot control system for an unmanned aerial vehicle (UAV) has been proposed and partly developed. Relative to prior such systems, this would be a lightweight, inexpensive autopilot system offering enhanced computational power and flexibility that would enable the use of the system in a variety of advanced UAVs. The two-processor architecture represents a significant departure from most prior single-processor UAV-autopilot architectures. Moreover, because this particular two-processor architecture is an open one, based on the use of commercial- off-the-shelf (COTS) processors and other COTS electronic subsystems, the system could easily be upgraded to take advantage of available state-of-the-art equipment.

Posted in: Briefs, Information Technology, Architecture, Unmanned aerial vehicles
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Automatic Abstraction of Information From Digitized Images

A research effort now underway addresses fundamental mathematical issues involved in a methodology of creating flexible machine vision systems that would be able to modify their behaviors and evolve in particular environments so as to recognize anything that human operators have designated as being "interesting" in those environments. It is intended that a person who is not a programmer could train such a machine vision system by drawing lines around objects in a scene (see figure) or otherwise indicating example objects and that thereafter, the system would adapt and evolve the ability to recognize such objects automatically.

Posted in: Briefs, Information Technology, Imaging
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Data Fusion for Space Situational Awareness

Satellites greatly enhance US defense operations; however, these key assets are vulnerable to perils such as space weather and acts of aggression. Unfortunately, it is difficult to determine the cause of anomalies from the ground. What may first appear as a routine system glitch may, in fact, be something much more serious. Providing the ability to detect—and in some cases, predict—events via multiple data sources can be critical to mission success and the safeguarding of space assets. Threat analysts must be able both to distinguish external, man-made threats, natural threats, and environmental conditions from internal, satellite bus anomalies in real time and to subsequently perform mitigating actions.

Posted in: Briefs, Information Technology
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Intelligence Fusion System Tracks Mobile Targets

Current intelligence fusion systems are not accurately and quickly performing the intelligence, surveillance, and reconnaissance (ISR) fusion necessary for tracking moving targets that use camouflage, concealment, and deception to avoid detection. Combatant commanders require a more flexible and responsive capability to engage fleeting and mobile targets.

Posted in: Briefs, Information Technology
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A Concept for Information Extraction From Remote Wireless Sensor Networks

Recent advances in the development of microsensors, microprocessors, information fusion algorithms, and ad hoc networking have led to increasingly capable wireless sensor networks. These networks, when deployed to monitor an urban area, show great promise in enhancing warfighter situational awareness. However, delivering the sensor network's collected information back to the proper decision makers is one network capability that still requires improvement. To bridge this gap between the tactical operations center and multiple wireless sensor networks distributed across a city, engineers must create a system-of-systems architecture. This architecture must permit a warfighter to receive near-real-time sensor information from an out-of-theater operating post, whether a mile or an ocean away. Research accomplished in efforts such as the Defense Advanced Research Projects Agency's (DARPA) Information Exploitation Office sponsored Networked Embedded Systems Technology (NEST) program has provided information gathering algorithms for wireless sensor networks that are independent of the hardware platform on which they run. Nevertheless, these networks have no means for publishing the massive amounts of information to the Global Information Grid (GIG). To address this publication requirement, AFRL engineers have begun integrating NEST technologies with the Joint Battlespace Infosphere (JBI).1, 2 They recently developed a proof-of-concept demonstration of this idea for Scientific Advisory Board (SAB) review. In this demonstration, they integrated a tracking application developed for the NEST program with the AFRL developed JBI Reference Implementation and showcased the resultant capability to connect low-level information gatherers to high-level information distributors.

Posted in: Briefs, Information Technology
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Military Worth Analysis of New Concept Weapons

Weapon systems analysts traditionally conduct military worth analysis (MWA) to evaluate the warfighter payoff resulting either from the development and implementation of new assets or from the establishment of new concepts of employment for existing assets. Analysis scope ranges from the campaign level to the mission level and thus differs in magnitude, time frame, and level of detail (see Figure 1). While MWA can potentially evaluate hundreds of possible metrics, it typically includes parameters such as time to accomplish objectives, number of targets neutralized, amount of collateral damage, and volume of resources consumed (including dollars). As depicted in Figure 2, laboratory directors must consider both the analytically demonstrated payoff and the clear interest of the user community in making an informed investment decision; therefore, determining the MWA for a particular laboratory technology is vitally important.

Posted in: Briefs, Information Technology
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Developing Condition-Based Maintenance

Like any manufacturing equipment, semiconductor fabrication systems have a finite lifetime. Technicians normally perform maintenance on these hardware systems according to preset schedules and regardless of actual need, which results in unnecessary equipment downtime and needless costs incurred as a result of lost production time and additional maintenance labor. AFRL scientists teamed with researchers from the University of New Mexico (UNM) to examine the feasibility of establishing prognostics for such expensive and valuable machinery and to devise a mechanism for scheduling equipment maintenance based on needs rather than calendar cycles. This so-called condition-based maintenance has the potential to increase equipment availability, improve productivity, enhance safety, and reduce expenses. The ultimate objective of the AFRL/UNM collaboration is to develop a data-driven prognostic system that provides advanced warning of failures, faults, and other error events that occur in complex systems.

Posted in: Briefs, Information Technology
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Response Surface Mapping Technique Aids Warfighters

When weaponeering a target, military planners pinpoint a detonation location that will result in the desired damage to the entire target, or even a particular area within the target. The warfighter then selects the most suitable delivery platform— aircraft, weapon, guidance package, release altitude, and speed— for inflicting the appropriate damage to the target. Determining the proper combination of variables capable of producing the desired effect on a hardened target requires the warfighter to understand the penetration dynamics of the weapon; it also relies on the individual's ability to adjust the variables within his or her control, as necessary. For a scenario in which the destruction of a specific target is often coupled with the mitigation of collateral damage, it is imperative that the warfighter make proper decisions regarding weapons selections. AFRL scientists, collaborating with other Department of Defense agencies, applied innovative data mining and visualization methods to aid warfighter efficiency and effectiveness in making these choices.

Posted in: Briefs, Information Technology, Cartography, Data acquisition and handling, Imaging, Terrain, Military vehicles and equipment
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Coordination of Autonomous Unmanned Air Vehicles

Future autonomous unmanned air vehicles (UAV) will need to work in teams to share information and coordinate activities in much the same way as current manned air systems. Funded by AFRL, Professor Hugh Durrant-Whyte and his research staff (see Figure 1) at the Australian Research Council's Center of Excellence for Autonomous Systems have been developing mathematical models and simulation studies to understand—and ultimately provide— this future UAV capability.

The team's research focuses on coordination and cooperation for teams of autonomous UAVs engaged in information gathering and data fusion tasks, including cooperative tracking, ground picture compilation, area exploration, and target search. The underlying mathematical model for coordination and cooperation employs quantitative probabilistic and information-theoretic models of platform and sensor abilities. This information-theoretic approach builds on established principles for distributed data fusion in sensor networks, extending these ideas to problems in the distributed control of sensing resources. The researchers have made substantial progress towards formulating, solving, and demonstrating these methods for multi-UAV systems. In particular, they have developed distributed algorithms that enable UAV team-based search and exploration operations. These search and exploration algorithms can incorporate realistic constraints on platforms and sensors—a priori constraints from the environment and weak information from external sources. To date, Prof Durrant-Whyte's research team has successfully demonstrated these algorithms on a flight simulator of midlevel fidelity (see Figure 2).

Recently, the team presented its findings to AFRL researchers at Wright- Patterson Air Force Base (AFB), Ohio, and Eglin AFB, Florida. Based on the promising results of this research effort, AFRL is funding two additional projects to further explore the mathematical aspects of the technology and facilitate real-world application through demonstrations. The first round of demonstrations will involve high-fidelity, hardware-in-the-loop simulations, culminating in a large-scale demonstration involving a UAV fleet operated by the University of Sydney (see Figure 3). AFRL's two research projects will provide significant scientific and technical advancement in the cooperative control of autonomous systems.

The availability of autonomous UAV teams capable of complex cooperative behavior will enable warfighters to execute highly complex missions effectively and safely removed from harms way (i.e., remotely). In addition to providing these advantages, the UAV technology's imaging and atmospheric sampling capabilities have the potential to support both homeland security emergency scenarios and real-time forest fire monitoring tasks.

Dr. Tae-Woo Park, of the Air Force Research Laboratory's Air Force Office of Scientific Research, and Prof Hugh Durrant-Whyte, of the University of Sydney (Australian Research Council Federation Fellow), wrote this article. For more information, contact TECH CONNECT at (800) 203-6451 or place a request at http://www.afrl.af.mil/techconn/index.htm. Reference document OSR-H-05-06.

Posted in: Briefs, Information Technology, Mathematical models, Simulation and modeling, Unmanned aerial vehicles
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