7,449 research outputs found
Formal proof of the AVM-1 microprocessor using the concept of generic interpreters
A microprocessor designated AVM-1 was designed to demonstrate the use of generic interpreters in verifying hierarchically decomposed microprocessor specifications. This report is intended to document the high-order language (HOL) code verifying AVM-1. The organization of the proof is discussed and some technical details concerning the execution of the proof scripts in HOL are presented. The proof scripts used to verify AVM-1 are also presented
The formal verification of generic interpreters
The task assignment 3 of the design and validation of digital flight control systems suitable for fly-by-wire applications is studied. Task 3 is associated with formal verification of embedded systems. In particular, results are presented that provide a methodological approach to microprocessor verification. A hierarchical decomposition strategy for specifying microprocessors is also presented. A theory of generic interpreters is presented that can be used to model microprocessor behavior. The generic interpreter theory abstracts away the details of instruction functionality, leaving a general model of what an interpreter does
Environmental modeling and recognition for an autonomous land vehicle
An architecture for object modeling and recognition for an autonomous land vehicle is presented. Examples of objects of interest include terrain features, fields, roads, horizon features, trees, etc. The architecture is organized around a set of data bases for generic object models and perceptual structures, temporary memory for the instantiation of object and relational hypotheses, and a long term memory for storing stable hypotheses that are affixed to the terrain representation. Multiple inference processes operate over these databases. Researchers describe these particular components: the perceptual structure database, the grouping processes that operate over this, schemas, and the long term terrain database. A processing example that matches predictions from the long term terrain model to imagery, extracts significant perceptual structures for consideration as potential landmarks, and extracts a relational structure to update the long term terrain database is given
Towards composition of verified hardware devices
Computers are being used where no affordable level of testing is adequate. Safety and life critical systems must find a replacement for exhaustive testing to guarantee their correctness. Through a mathematical proof, hardware verification research has focused on device verification and has largely ignored system composition verification. To address these deficiencies, we examine how the current hardware verification methodology can be extended to verify complete systems
Early Modern Russian Letters
Early Modern Russian Letters: Texts and Contexts brings together twenty essays by Marcus C. Levitt, a leading scholar of eighteenth-century Russian literature. The essays address a spectrum of works and issues that shaped the development of modern Russian literature, from authorship and philosophy to gender and religion in Russian Enlightenment culture. The first part of the collection explores the career and works of Alexander Sumarokov, who played a formative role in literary life of his day. In the essays of the second part Levitt argues that the Enlightenment’s privileging of vision played an especially important role in eighteenth-century Russian self-image, and that its “occularcentrism” was profoundly shaped by Orthodox religious views. Early Modern Russian Letters offers a series of original and provocative explorations of a vital but little studied period
ELSA: An Integrated, Semi-Automated Nebular Abundance Package
We present ELSA, a new modular software package, written in C, to analyze and
manage spectroscopic data from emission-line objects. In addition to
calculating plasma diagnostics and abundances from nebular emission lines, the
software provides a number of convenient features including the ability to
ingest logs produced by IRAF's splot task, to semi-automatically merge spectra
in different wavelength ranges, and to automatically generate various data
tables in machine-readable or LaTeX format. ELSA features a highly
sophisticated interstellar reddening correction scheme that takes into account
temperature and density effects as well as He II contamination of the hydrogen
Balmer lines. Abundance calculations are performed using a 5-level atom
approximation with recent atomic data, based on R. Henry's ABUN program.
Improvements planned in the near future include use of a three-region
ionization model, similar to IRAF's nebular package, error propagation, and the
addition of ultraviolet and infrared line analysis capability. Detailed
documentation for all aspects of ELSA are available at
http://www.williams.edu/Astronomy/research/PN .Comment: 2 pages, contributed paper, IAU Symp. 234, Planetary Nebulae in Our
Galaxy and Beyon
Early Modern Russian Letters
Early Modern Russian Letters: Texts and Contexts brings together twenty essays by Marcus C. Levitt, a leading scholar of eighteenth-century Russian literature. The essays address a spectrum of works and issues that shaped the development of modern Russian literature, from authorship and philosophy to gender and religion in Russian Enlightenment culture. The first part of the collection explores the career and works of Alexander Sumarokov, who played a formative role in literary life of his day. In the essays of the second part Levitt argues that the Enlightenment’s privileging of vision played an especially important role in eighteenth-century Russian self-image, and that its “occularcentrism” was profoundly shaped by Orthodox religious views. Early Modern Russian Letters offers a series of original and provocative explorations of a vital but little studied period
Study of fault-tolerant software technology
Presented is an overview of the current state of the art of fault-tolerant software and an analysis of quantitative techniques and models developed to assess its impact. It examines research efforts as well as experience gained from commercial application of these techniques. The paper also addresses the computer architecture and design implications on hardware, operating systems and programming languages (including Ada) of using fault-tolerant software in real-time aerospace applications. It concludes that fault-tolerant software has progressed beyond the pure research state. The paper also finds that, although not perfectly matched, newer architectural and language capabilities provide many of the notations and functions needed to effectively and efficiently implement software fault-tolerance
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