Information Science

The Dataflow Interchange Format for Designing DSPs

The dataflow interchange format (DIF) is a conceptual framework for helping designers of digital signal-processing (DSP) systems to integrate diverse dataflow models, dataflow techniques, DSP-design software tools, DSP software libraries, and embedded processing platforms. Somewhat more specifically, the DIF is intended to afford a unique combination of capabilities for (1) developing dataflow models and techniques for exploring the complex design spaces for embedded DSP systems; (2) porting DSP designs across various software tools, libraries, and embedded processing platforms; and (3) synthesizing software implementations from high-level, dataflow-based program specifications.

Posted in: Briefs, Information Technology
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Thwarting Code-Injection Attacks Using SDT-Based ISR

An improved method has been devised for defending a server or other computer against a code-injection attack, in which an attacker exploits a hardware or software vulnerability to inject harmful or otherwise unwanted code into an application program that is being executed and then causes the injected code to be executed. The present improved defense method provides for a secure and efficient implementation of instruction-set randomization (ISR), incorporating several advances beyond related prior methods that utilize ISR.

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Some Advances in Digital-Image Forensics

A program of research in the forensic analysis of digital images has yielded several proposed techniques for automated image-data processing to answer questions concerning the source, authenticity, and integrity of a given image or set of images. The need for such techniques arises because the ease with which digital images can be created and altered without leaving obvious traces can give rise to doubts about their credibility, especially when they are used as legal evidence. Like other proposed techniques of image forensics, the techniques reported here are subject to limitations. Because none of the techniques by itself offers a definitive solution to the digital-image-verification problem, the research continues in an effort to propose new techniques and combine them with existing techniques to obtain more reliable decisions.

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Parametric Design of Three-Dimensional Hydrodynamic Shapes

A method of parametric design of bodies having arbitrary three- dimensional shapes has been invented. The method is intended mainly for use in the design, analysis, and manufacture of propeller and propulsor blades, submarine sails, ship hulls, rudders, control vanes, sonar domes, and other bodies for which hydrodynamic or aerodynamic properties are important considerations.

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Development of Adaptive and Reflective Middleware

A report describes Phase II of the Adaptive and Reflective Middleware Systems (ARMS) program, which was focused on developing an adaptive and reflective network Quality-of-Service (QoS) infrastructure for the Total Ship Computing Environment (TSCE). Conceived for the next generation of Navy surface ships, the TSCE is associated with a computing architecture characterized by modularity, extensibility, scalability, and amenability to upgrading of all software and hardware systems. A major feature of the ARMS approach is the use of a bandwidth broker that provides admission control and leverages differentiated-services and class-of-service functionalities of high end routers and switches in order to guarantee end-to-end QoS in a heterogeneous computing environment. Building upon the Phase I product, the Phase II development (1) provides continued assurance of network QoS for mission- critical tasks in the presence of single mode faults and such catastrophic faults as the loss of an entire data center, and (2) improves timely adaptation to network performance using probes and instrumentation to measure delay. The ARMS development also raises the level of abstraction in the use of model-driven development software tools for configuring, deploying, and achieving QoS in distributed real-time embedded systems.

This work was done by Balakrishnan Dasarathy of Telcordia Technologies, Inc. for the Defense Advanced Research Projects Agency.

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Multiscale Virtual Design and Testing of Materials

Progress has been made in research on several fronts in an effort to develop computational simulation capabilities for use in virtual design and testing of advanced structural materials. It is envisioned that the capabilities will be embodied in a coherent set of methods, software to implement the methods, and advances in the fundamental understanding of many issues in the thermomechanical performance of materials. It is further envisioned that the methods and software will be organized into a hierarchy (see figure) corresponding to a hierarchy of spatial scales from electronic through atomic, mesoscale, microstructural, and continuum to macrostructural, and that there will be seamless coupling of information from each scale to the next larger scale. A secondary objective of this research and development effort is to provide direct simulation output at each level of the hierarchy for investigating specific phenomena at the corresponding spatial scale. For the purposes of demonstrating the capabilities and providing specific focus for the overall research, it is intended to predict nano-, micro-, and macroscopic degradation of aluminum and titanium alloys under fatigue loading and in a corrosive (oxidative) environment and as a function of temperature.

Posted in: Briefs, Information Technology, Design processes, Simulation and modeling
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Autonomous Vehicles Would Learn by Mimicking Human Drivers

A program initiated by the Defense Advanced Research Projects Agency (DARPA) and now also pursued by other agencies called “Learning Applied to Ground Robots” (LAGR), is developing control algorithms that would enable a robotic land vehicle, robotic underwater crawler, or other similar autonomous mobile robot to traverse terrain safely. Among the algorithms needed are navigation algorithms for finding and then following a safe path across terrain from a starting or current position to a destination.

Posted in: Briefs, Information Technology, Vehicle drivers, Robotics, Autonomous vehicles
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Advances in Algorithms for CFD and Finite-Element Simulation

A program of research and development has resulted in some advances in algorithms for computational fluid dynamics (CFD), finite-element simulation of solid objects undergoing large deformations, and some related topics. The main advances are summarized as follows:

Posted in: Briefs, Information Technology, Computational fluid dynamics, Finite element analysis
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Shape-Based Recognition of 3D Objects in 2D Images

An object-recognition algorithm analyzes data from two-dimensional (2D) images to locate and identify possibly complexly shaped three-dimensional (3D) objects in possibly highly cluttered scenes depicted in the images. More specifically, the algorithm implements a relatively simple, effective, and fast process for recognizing 2D objects that may be partly occluded and that have shapes that can be modeled by use of sets of line segments (see figure). Because the algorithm tolerates a fair amount of perspective distortion, it is also applicable to 3D objects represented by sets of viewpoint- dependent 2D models.

Posted in: Briefs, Information Technology, Mathematical models, Imaging
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Application of CFD to a Slender-Bodied, Finned Projectile

In an application of computational fluid dynamics (CFD), flow fields about a slender-bodied finned projectile and the resulting aerodynamic forces and moments on the projectile were computed. The size and shape of the projectile (a blunt-nosed, ogivecylinder body, 316.7 mm long, 23.5 mm in diameter, with four tail fins) are representative of a preliminary design of a future air-defense projectile. The computations are exemplary of those needed for predicting aerodynamic performances in order to optimize designs of advanced projectiles, missiles, and rockets in general.

Posted in: Briefs, Information Technology, Computational fluid dynamics, Missiles
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