Application of digital interferogram evaluation techniques to the measurement of 3-D flow fields

A system for digitally evaluating interferograms, based on an image processing system connected to a host computer, was implemented. The system supports one- and two-dimensional interferogram evaluations. Interferograms are digitized, enhanced, and then segmented. The fringe coordinates are extracted, and the fringes are represented as polygonal data structures. Fringe numbering and fringe interpolation modules are implemented. The system supports editing and interactive features, as well as graphic visualization. An application of the system to the evaluation of double exposure interferograms from the transonic flow field around a helicopter blade and the reconstruction of the three dimensional flow field is given

Reconstruction of a three-dimensional, transonic rotor flow field from holographic interferogram data

Holographic interferometry and computerized aided tomography (CAT) are used to determine the transonic velocity field of a model rotor blade in hover. A pulsed ruby laser recorded 40 interferograms with a 2 ft dia view field near the model rotor blade tip operating at a tip Mach number of 0.90. After digitizing the interferograms and extracting the fringe order functions, the data are transferred to a CAT code. The CAT code then calculates the perturbation velocity in several planes above the blade surface. The values from the holography-CAT method compare favorably with previously obtained numerical computations in most locations near the blade tip. The results demonstrate the technique's potential for three dimensional transonic rotor flow studies

Transonic rotor flow-measurement technique using holographic interferometry

Holographic interferometry is used to record interferograms of the flow near a hovering transonic rotor blade. A pulsed ruby laser recorded 40 interferograms with a 2 ft dia. view field near the model rotor blade tip operating at a tip Mach number of 0.90. The experimental procedure is presented and example interferograms recorded in the rotor's tip path plane. In addition, a method currently being pursued to obtain quantitative flow information using computer assisted tomography (CAT) with the holographic interferogram data, is outlined

Topics in Data Stream Sampling and Insider Threat Detection

With the current explosion in the speed and volume of data, the conventional computation systems are not capable of dealing with large data efficiently. In this project, we do research in the data stream sampling methods and an application on insider threat detection. The goal of random sampling is to select a subset from the original population so that the subset can represent the whole population. In many real world applications, by sampling a subset from the original population, we can estimate the global statistical properties, such as mean, variance, probability distribution, etc. The goal of random sampling from a distributed stream is to select a subset from the union of the streams such that each element in the distributed stream is sampled with equal probability. In some cases, the “Heavy Hitters” dominate the random sample. The heavy hitters are the elements with high frequency. The distinct random sample can be applied so that the elements with low frequency can also be seen. Distinct sampling from a distributed stream is proposed to extract a subset from the unique set of the union of the distributed stream. In database query optimization, sampling unique subset from the population is an important task. Random sampling and distinct sampling are among the fundamental techniques and algorithms for large scale data analysis and the query enhancement over database systems. We propose algorithms, theoretical analysis, and experimental evaluations on random sampling and distinct sampling from a distributed stream. Nowadays, with more and more attacks on the computer systems, it is important to know how we protect our computer systems or classified information from hackers or attackers. Among all the attack or data breaches, more and more cases come from inside of an organization. It is called “Insider Threat.” In recent reports, malicious insiders are causing enormous damages in organizations. We propose two insider threat detection framework that monitors the system logs and detect anomaly behaviors. We propose a Scenario-based Insider Threat Detection method and a Session-based Insider Threat Detection. We implement our framework in Java, and present experimental evaluation on a synthetic dataset

A New Model of Interpreting Modified Strophic Design: Brahms’s Late Viennese Solo Lieder

The study of the interaction between musical and text-based elements in songs has received a great amount of attention in recent years. Although numerous previous researchers have contributed to the study of Brahms’s Lieder, more work remains to explore Brahms’s various compositional techniques of modification to reveal the music-text relationship and performance implications in his strophic songs. Since the majority of Brahms’s modified strophic songs were composed during his later Viennese period (1875–97), this dissertation offers a thorough analysis of Brahms’s late twenty-eight strophic solo Lieder and develops a new formal model to categorize them as one of four types of modified strophic form (hereafter MSF): Type-1 MSF: Slight Modifications; Type-2 MSF: Changes to Phrase Rhythm; Type-3 MSF: Changes of Key; and Type-4 MSF: Significant Modifications. This dissertation employs varied analytical methods and approaches (e.g., hypermetrical reconstructions and voice-leading reductions) to establish four primary strategies by which to interpret Brahms’s modified strophic design. To make the meaning of the poem more closely integrated with Brahms’s musical setting, I suggest that performers should display different emphases and interpretations to reflect Brahms’s changes to melody, accompaniment, phrase rhythm, and harmonization. Thus, my thorough analysis attempts to motivate researchers to rethink and connect Brahms’s solo Lieder with these four areas of music-theoretical attention—analysis and performance, rhythm and meter, large-scale organization, and music-text relations. This in-depth exploration into Brahms’s compositional tendencies during his later Viennese period will facilitate future research into additional solo modified strophic Lieder of both Brahms and his contemporaries