Use of a digital tone extractor for real-time phase analysis

A digital tone extractor which monitors the phase integrity of a VLBI recording system in real time was developed. The digital tone extractor monitors phase calibrator tones injected at the antenna and tracks their phase as a function of time. It is capable of maintaining 0.001 cycle phase accuracy over the course of a VLBI experiment in accordance with the accuracy requirements of centimeter VLBI work. This real time VLBI system monitor is a safeguard against most instrumental breakdowns and operator errors

Techniques, based on extremal subspaces, for improved reconstruction of signals from samples

Extremal subspaces techniques for reconstruction of signal from sample

Automated Pilot Advisory System

An Automated Pilot Advisory System (APAS) was developed and operationally tested to demonstrate the concept that low cost automated systems can provide air traffic and aviation weather advisory information at high density uncontrolled airports. The system was designed to enhance the see and be seen rule of flight, and pilots who used the system preferred it over the self announcement system presently used at uncontrolled airports

Evaluation of Malware Target Recognition Deployed in a Cloud-Based Fileserver Environment

Cloud computing, or the migration of computing resources from the end user to remotely managed locations where they can be purchased on-demand, presents several new and unique security challenges. One of these challenges is how to efficiently detect malware amongst files that are possibly spread across multiple locations in the Internet over congested network connections. This research studies how such an environment will impact the performance of malware detection. A simplified cloud environment is created in which network conditions are fully controlled. This environment includes a fileserver, a detection server, the detection mechanism, and clean and malicious file sample sets. The performance of a novel malware detection algorithm called Malware Target Recognition (MaTR) is evaluated and compared with several commercial detection mechanisms at various levels of congestion. The research evaluates performance in terms of file response time and detection accuracy rates. Results show that there is no statistically significant difference in MaTR\u27s true mean response time when scanning clean files with low to moderate levels of congestion compared to the leading commercial response times with a 95% confidence level. MaTR demonstrates a slightly faster response time, by roughly 0.1s to 0.2s, at detecting malware than the leading commercial mechanisms\u27 response time at these congestion levels, but MaTR is also the only device that exhibits false positives with a 0.3% false positive rate. When exposed to high levels of congestion, MaTR\u27s response time is impacted by a factor of 88 to 817 for clean files and 227 to 334 for malicious files, losing its performance competitiveness with other leading detection mechanisms. MaTR\u27s true positive detection rates are extremely competitive at 99.1%

Validity of the Gor'kov expansion near the upper critical field in type II superconductors

We have examined the validity of the Gor'kov expansion in the strength of the order parameter of type II superconductors near the upper critical field. Although the degeneracy of the electron levels in a magnetic field gives non- perturbative terms in the solution to the Bogoliubov-de Gennes equations we find, contrary to recent claims, that these non-perturbative terms cancel in the expression for the thermodynamic potential, and that the traditional Gor'kov theory is correct sufficiently close to Hc2 at finite temperature. We have derived conditions for the validity of the Gor'kov theory which essentially state, that the change in the quasiparticle energies as compared to the normal state energies cannot be too large compared to the temperature.Comment: 5 pages, 3 figures. One reference adde

Welding high-strength aluminum alloys

Handbook has been published which integrates results of 19 research programs involving welding of high-strength aluminum alloys. Book introduces metallurgy and properties of aluminum alloys by discussing commercial alloys and heat treatments. Several current welding processes are reviewed such as gas tungsten-arc welding and gas metal-arc welding

Contribution Among Antitrust Defendants

This Recent Development argues that no single federal common law rule of contribution exists and that federal securities law decisions provide the best analogy from which to imply a right of contribution under the antitrust laws. Thus, the Recent Development proposes that the Supreme Court should fashion a rule permitting contribution among antitrust defendants