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An Examination Of Multi-Tier Designs For Legacy Data Access, Michael L. Acker Dec 1997

An Examination Of Multi-Tier Designs For Legacy Data Access, Michael L. Acker

Theses and Dissertations

This work examines the application of Java and the Common Object Request Broker Architecture (CORBA) to support access to remote databases via the Internet. The research applies these software technologies to assist an Air Force distance learning provider in improving the capabilities of its World Wide Web-based correspondence system. An analysis of the distance learning provider's operation revealed a strong dependency on a non-collocated legacy relational database. This dependency limits the distance learning provider's future web-based capabilities. A recommendation to improve operation by data replication is proposed, and the implementation details are provided for two alternative test systems that support …


Developing A Corpus Specific Stoplist Using Quantitative Comparison, Craig N. Berg Dec 1997

Developing A Corpus Specific Stoplist Using Quantitative Comparison, Craig N. Berg

Theses and Dissertations

We have become overwhelmed with electronic information and it seems our situation is not going to improve. It is becoming increasingly common for people to work with information on a daily basis. We seem to spend more and more time looking for information, and it is taking longer because more information is available. This thesis will look at how we can provide faster access to the information we want to find. Today's requirements are closely related to searching for information using queries. At the heart of the query process is the removal of search terms having little or no significance …


A Representational Approach To Knowledge And Multiple Skill Levels For Broad Classes Of Computer Generated Forces, Larry J. Hutson Dec 1997

A Representational Approach To Knowledge And Multiple Skill Levels For Broad Classes Of Computer Generated Forces, Larry J. Hutson

Theses and Dissertations

Current computer generated forces (CGFs) in the 'synthetic battlespace', a training arena used by the military, exhibit several deficiencies. Human actors within the battlespace rapidly identify these CGFs and defeat them using unrealistic and potentially fatal tactics, reducing the overall effectiveness of this training arena. Simulators attached to the synthetic battlespace host local threat systems, leading to training inconsistencies when different simulators display the same threat at different levels of fidelity. Finally, current CGFs are engineered 'from the ground up', often without exploiting commonalities with other existing CGFs, increasing development (and ultimately training) costs. This thesis addresses these issues by …


Speaker Verification In The Presence Of Channel Mismatch Using Gaussian Mixture Models, Robert B. Reid Dec 1997

Speaker Verification In The Presence Of Channel Mismatch Using Gaussian Mixture Models, Robert B. Reid

Theses and Dissertations

A channel compensation method is sought for use in speaker identification (ID) and verification applications under matched and mismatched training and testing conditions. This work expands on previous work on matched conditions by investigating three techniques on matched and mismatched conditions using the TIMIT and NTIMIT speech databases. First, previous results on 168 speakers are reproduced for matched conditions using Gaussian mixture models (GMM) and mel-frequency cepstral coefficients. Next, cepstral mean subtraction with band limiting (CMSBL) is investigated. The third method, developed in this thesis uses a modified Wiener filtering approach to channel compensation. New GMMs are created for each …


A Performance Analysis Of The Faugeras Color Space As A Component Of Color Histogram-Based Image Retrieval, Chad A. Vander Meer Dec 1997

A Performance Analysis Of The Faugeras Color Space As A Component Of Color Histogram-Based Image Retrieval, Chad A. Vander Meer

Theses and Dissertations

The use of color histograms for image retrieval from databases has been implemented in many variations. Selecting the appropriate color space for similarity comparisons is an important part of a color histogram technique. This paper serves to introduce and evaluate the performance of a color space through the use of color histograms. Performance is evaluated by correlating the similarity results obtained from various color feature vector techniques (including color histgramming) to those gathered through a human perceptual test. The perceptual test required 36 human subjects to evaluate the similarity of 10 military aircraft images. The same 10 images were also …


A Validation Of The Parameterized Real-Time Ionospheric Specification Model (Prism) Version 1.7b, Shawn D. Filby Nov 1997

A Validation Of The Parameterized Real-Time Ionospheric Specification Model (Prism) Version 1.7b, Shawn D. Filby

Theses and Dissertations

The most current version of the Parameterized Real-time Ionospheric Specification Model (PRISM), version 1.7b, was validated using Digital Ionospheric Sounding System (DISS) measurements of F2 layer critical frequency (foF2) and F2 peak electron density height (hmF2) as the "ground truth." PRISM was executed, first, with no real-time input parameter and, second, with Global Positioning System (GPS) Total Electron Content (TEC) measurements as the sole real-time parameter. Hourly values of hmF2 and foF2 over 123 days in 1994-1996 (solar minimum conditions) and covering three seasons (equinox, summer solstice, and winter solstice) were compared for Wallops Island, Virginia, and Point Arguello, California, …