National Security Agency

About: National Security Agency is a government organization based out in Fort George Meade, Maryland, United States. It is known for research contribution in the topics: Signal & Encryption. The organization has 393 authors who have published 485 publications receiving 15916 citations. The organization is also known as: NSA & N.S.A..

Cyber Buzz: Examining Virality Characteristics of Cybersecurity Content In Social Networks:

Abstract: The Internet is a rich environment for information to spread rapidly and widely. The ability of cybersecurity content to achieve virality in social networks can be useful for measuring security awa...

Promoting Ada at the National Security Agency

Abstract: Similar to the barriers faced by Ada proponents in commercial industry and other branches of the Department of Defense, we have faced many difficulties in adopting Ada at the National Security Agency (NSA). The difficulties encountered when introducing Ada, though often proclaimed to be tec~lcal problems, actually stem more from people’s unfavorable perceptions of the language. Hidden behind technical excuses, the negative attitudes towards Ada are a resistive barrier to the spread of Ada’s use. This paper identifies some of the technical and attitudinal barriers that exist at NSA, attempts to explain why they exist, introduces some methods being used to diminish or eliminate the barriers, and discusses previous and current Ada development projects. Introduction The introduction of Ada at the National Security Agency (NSA), just as witMn most of the software development world, has been slow and faced its share of obstacles. From the mountains to the molehills, we have had to tackle the common excuses and genuine problems posed by developers and managers alike. From the C fanatics to the “old dogs”, Ada has faced opposition. To overcome some of the obstacles and opposition, we formulated a two-part strategy -identify the barriers and deal with them the best way possible. After asking numerous questions (regarding the lack of Ada development efforts at NSA) and receiving many unjustifiable answers, we determined that the barriers stem more from the attitudes people have formed towards Ada than from actual technical problems they encountered using Ada. The technical barriers were already being addressed, the impact of adverse attitudes or how to handle them had not been adequately 1991 ACM 0-89791445-7191 I1OOO-0191

Device for securing a door

Abstract: A device for securing a door includes an elongated flat rigid member. A first segment is connected to a second segment by a transition segment perpendicular to the first and second segments. The first segment forms an aperture to admit a restraining device. The device also includes a first blocking member having two apertures and configured to engage the first member such that the restraining device restrains the first blocking member relative to the flat rigid member. The device also includes a second blocking member configured to lockably engage the second segment, thereby securing the device relative to a frame of the door with the first and second segments on opposite sides of the frame. When the device is secured and the door closed, and the first blocking member restrained relative to the flat rigid member, the door is blocked from being opened by the first and second blocking members.

Toward Automating the Discovery of Decreasing Measures

Abstract: An often neglected part of proof automation is simply admitting recursive function definitions into a constructive logic. Since function termination in general is undecidable, current generation theorem provers are quick to involve the human. There is, however, a substantial subset of the class of recursive functions for which termination arguments can be provided automatically. In particular, when the ordinal measure used to justify termination is less than $$\omega^{\omega}$$ , we provide algorithms and proofs that guarantee optimum results, given the capability of existing proof libraries on the theorem-proving system.

Estimation of the continuously varying Doppler effect

Abstract: There are many applications for which it is important to resolve the location and motion of a target position. For the static situation in which a target transmitter and several receivers are not in motion, the target may be completely resolved by triangulation using relative time delays estimated by several receivers at known locations. These delays are normally estimated from the location of peaks in the magnitude of the cross-correlation function. For active radars, a transmitted signal is reflected by the target, and range and radial velocity are estimated from the delay and Doppler effects on the received signal. In this process, Doppler effects are conventionally modeled as a shift in frequency, and delay and Doppler are estimated from a cross-ambiguity function (CAF) in which delay and Doppler frequency shift are assumed to be independent and approximately constant. Delay and Doppler are jointly estimated as the location of the peak magnitude of the CAF plane. We present methods for accurately estimating delay for the static case and delay and the time-varying Doppler effects for non-static models, such as the radar model.