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Adaptive control systems - combined optimization and adaptive control, analysis-synthesis and passive adaptive systems, learning systems, and measurement adaptive systems
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This report refutes claims is that adaptive routing performs better than dimension-order routing. Simulation results are presented that show dimension-order routing achieves both higher throughput and lower latency than adaptive r...
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This report refutes claims is that adaptive routing performs better than dimension-order routing. Simulation results are presented that show dimension-order routing achieves both higher throughput and lower latency than adaptive routing. Specious claims for the advantages of adaptive routing are critiqued.
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The main objectives of this project were to develop real-time numerical algorithms for adaptive filtering, identification, and control. Derivation of mathematical theory to analyze and predict the performance of the adaptive algor...
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The main objectives of this project were to develop real-time numerical algorithms for adaptive filtering, identification, and control. Derivation of mathematical theory to analyze and predict the performance of the adaptive algorithms in the presence or unmodeled noise also was an important part of the project. Much of the research was aimed at supporting Airborne Laser-related research at the Air Force Research Laboratory. The algorithms developed were designed especially for the adaptive optics, adaptive image processing and target tracking, and blind identification and deconvolution.
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The objective of this study was to assess information technology tools to counter asymmetric threats when considered as complex adaptive systems (CASs). We focused primarily on the use of agent-based modeling and simulation techno...
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The objective of this study was to assess information technology tools to counter asymmetric threats when considered as complex adaptive systems (CASs). We focused primarily on the use of agent-based modeling and simulation technology. This report describes both agent-based modeling (ABM) and an agent- based model developed to explore the utility of ABM technology to counter asymmetric threats. We conclude that while terrorist groups considered qua systems are undoubtedly adaptive, it is not obvious that they are complex in the strict theoretical sense of that term. As a consequence, it is not clear that terrorist threats are amenable to the analytic techniques afforded by complexity theory. Moreover, while ABM technology may offer significant value in many fields, it is not at all clear that the technology offers tactical value to counter these growing asymmetric threats. We argue that human behavior is too complex and too poorly understood to be accurately modeled in anything but a simplified and unenlightening way using the technology and agent-based modeling techniques currently available particularly for tactical advantage. The real value potentially inestimable value lies in the systematic and methodical process of making explicit the assumptions regarding the fundamental factors governing agent behavior used in the models.
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Numerical simulations of aircraft landing on a carrier are difficult due to complex geometry and complex flow physics. The flowfield is very unsteady and chaotic and adequate mesh resolution is crucial to a successful simulation. ...
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Numerical simulations of aircraft landing on a carrier are difficult due to complex geometry and complex flow physics. The flowfield is very unsteady and chaotic and adequate mesh resolution is crucial to a successful simulation. The goal of the proposed research is to deliver enhanced mesh adaptation capabilities that account for the chaotic unsteady nature of the flowfield about an aircraft in the landing approach path. Similar work was published by Shipman, et. al. [Shipman, Arunajatesan, Cavallo, Polsky] The objectives of the research are to explore three distinct mesh adaptation methods to handle the dynamic aspect of this case. The three methods include a hierarchical-Cartesian hexahedral method, an all-tetrahedral mesh method and a physics-based point placement/meshless method. The hierarchical method will subdivide cube-shaped elements to resolve geometry and gradients of user-selected adaptation functions, such as pressure or Mach number. The tetrahedral method is a traditional unstructured mesh method that incorporates adaptation through node movement to resolve gradients of the adaptation function. The third method is a meshless method that uses a physics-based force model to move nodes around to resolve the geometry and flowfield. The initial phase of the research conducted the first year developed steady-state analysis procedures for each method, with appropriate mesh adaptation capabilities. A description of the steady-state version of the three computer codes (TetFlow, OctFlow and PointFlow) is described in this report. The outcome of the research will provide insight into efficient and robust approaches for adaptive meshing for dynamic simulation of aircraft landings in the presence of unsteady carrier flowfield. Research is conducted assuming inviscid flow, but approaches will be applicable to viscous simulations with modifications.
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This document summarizes the principles of adaptive control systems and suggests a number of possible uses of this new technology on acoustic tracking ranges. A bibliography of recent literature is included. (Author)
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Optimal waveforms for minimum mean square error range profile estimation are investigated. An idealized measurement and waveform adaptation process is developed that yields optimal scene and range specific waveforms. This process ...
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Optimal waveforms for minimum mean square error range profile estimation are investigated. An idealized measurement and waveform adaptation process is developed that yields optimal scene and range specific waveforms. This process is idealized in that during each cycle of the process, a large number of dwells are required. As part of our method, a modified version of the Adaptive Pulse Compression (APC) estimation method is used to estimate the range profile after each dwell cycle. The proposed method is analogous to the APC method in that it yields a set of range specific optimal waveforms, while the APC method yields a set of range specific optimal pulse compression filters. In certain scenarios, the measurement and waveform adaptation process yields range profile estimates that are significantly better than those derived by the APC method alone.
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The goal of this project is to develop state-of-the-art modeling technologies for accurate representation of the ocean system as it evolves in time and space. The proposed adaptive vertical coordinate system is one of the innovati...
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The goal of this project is to develop state-of-the-art modeling technologies for accurate representation of the ocean system as it evolves in time and space. The proposed adaptive vertical coordinate system is one of the innovative technologies and will be applied to the ONR-initiated Expert System for use in a variety of ocean-related areas, including coupled physical-biogeochemical studies, climate simulations using combined atmosphere and sea-ice models, and coastal ocean predictions.
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The tutorial described in this report was conducted at the Human-Computer Interaction International Augmented Cognition Conference in Creta Maris, Crete, Greece, in June 2014. The purpose of this tutorial was 3-fold: 1) familiariz...
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The tutorial described in this report was conducted at the Human-Computer Interaction International Augmented Cognition Conference in Creta Maris, Crete, Greece, in June 2014. The purpose of this tutorial was 3-fold: 1) familiarize participants with the fundamental principles of adaptive Intelligent Tutoring System (ITS) design; 2) illustrate how ITS design influences/enables self-regulated learning; and 3) discuss the need for standards for authoring of ITS, modeling of learners and experts, automated instructional strategies, and methods of analysis for ITS technologies.
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