Mitre Corporation

About: Mitre Corporation is a company organization based out in Bedford, Massachusetts, United States. It is known for research contribution in the topics: Air traffic control & National Airspace System. The organization has 4884 authors who have published 6053 publications receiving 124808 citations. The organization is also known as: Mitre & MITRE.

Security for object-oriented database systems

Abstract: A design approach for a secure multilevel object-oriented database system is proposed by which a multilevel object-oriented system can be implemented on a conventional mandatory security kernel. Each object is assigned a single security level that applies to all its contents (variables and methods). The informal security policy model includes properties such as compatibility of security level assignments with the class hierarchy. After discussing the essential features of a general object system model, and then extending the object model to incorporate mandatory label-based security, it is shown how typical database security and integrity policies can be supported by this model, with special attention to inference problems and integrity constraints. The representation of integrity constraints and classification constraints are illustrated. >

Nanowire nanocomputer as a finite-state machine

Abstract: Implementation of complex computer circuits assembled from the bottom up and integrated on the nanometer scale has long been a goal of electronics research. It requires a design and fabrication strategy that can address individual nanometer-scale electronic devices, while enabling large-scale assembly of those devices into highly organized, integrated computational circuits. We describe how such a strategy has led to the design, construction, and demonstration of a nanoelectronic finite-state machine. The system was fabricated using a design-oriented approach enabled by a deterministic, bottom-up assembly process that does not require individual nanowire registration. This methodology allowed construction of the nanoelectronic finite-state machine through modular design using a multitile architecture. Each tile/module consists of two interconnected crossbar nanowire arrays, with each cross-point consisting of a programmable nanowire transistor node. The nanoelectronic finite-state machine integrates 180 programmable nanowire transistor nodes in three tiles or six total crossbar arrays, and incorporates both sequential and arithmetic logic, with extensive intertile and intratile communication that exhibits rigorous input/output matching. Our system realizes the complete 2-bit logic flow and clocked control over state registration that are required for a finite-state machine or computer. The programmable multitile circuit was also reprogrammed to a functionally distinct 2-bit full adder with 32-set matched and complete logic output. These steps forward and the ability of our unique design-oriented deterministic methodology to yield more extensive multitile systems suggest that proposed general-purpose nanocomputers can be realized in the near future.

Generating summaries from event data

Abstract: Summarization entails analysis of source material, selection of key information, condensation of this, and generation of a compact summary form. While there have been many investigations into the automatic summarization of text, relatively little attention has been given to the summarization of information from structured information sources such as data or knowledge bases, despite this being a desirable capability for a number of application areas including report generation from databases (e.g. weather, financial, medical) and simulations (e.g. military, manufacturing, economic). After a brief introduction indicating the main elements of summarization and referring to some illustrative approaches to it, this article considers specific issues in the generation of text summaries of event data. It describes a system, SumGen, which selects key information from an event database by reasoning about event frequencies, frequencies of relations between events, and domain specific importance measures. The article describes how SumGen then aggregates similar information and plans a summary presentation tailored to a stereotypical user. Finally, the article evaluates SumGen performance, and also that of a much more limited second summariser, by assessesing information extraction by 22 human subjects from both source and summary texts. This evaluation shows that the use of SumGen reduces average sentence length by approx. 15%, document length by 70%, and time to perform information extraction by 58%.

An Adaptive, Distributed Airborne Tracking System (process the Right Tracks at the Right Time)

Abstract: This paper describes a United States Air Force Advanced Technology Demonstration (ATD) that applied value-based scheduling to produce an adaptive, distributed tracking component appropriate for consideration by the Airborne Warning and Control System (AWACS) program. This tracker was designed to evaluate application-specific Quality of Service (QoS) metrics to quantify its tracking services in a dynamic environment and to derive scheduling parameters directly from these QoS metrics to control tracker behavior. The prototype tracker was implemented on the MK7 operating system, which provided native value-based processor scheduling and a distributed thread programming abstraction. The prototype updates all of the tracked-object records when the system is not overloaded, and gracefully degrades when it is. The prototype has performed extremenly well during demonstrations to AWACS operator and tracking system designers. Quantitative results are presented.

Performance of adaptive matched filter receivers over fading multipath channels

Abstract: A unified discrete channel model from the information source up to the sampler was developed for fading multipath channels. Different methods for adaptive channel measurement was studied. The performance of a discrete matched filter using different adaptation techniques and working over a troposcatter channel is predicted. It is shown that the effects of channel measurement noise are less damaging for the decision-directed adaptation technique as compared to any kind of reference-directed adaptation. >