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Full-Text Articles in Physical Sciences and Mathematics

Velocity Imaging For The Liquid–Gas Interface In The Near Field Of An Atomizing Spray: Proof Of Concept, David L. Sedarsky, Megan E. Paciaroni, Mark A. Linne, James R. Gord, Terrence R. Meyer Mar 2006

Velocity Imaging For The Liquid–Gas Interface In The Near Field Of An Atomizing Spray: Proof Of Concept, David L. Sedarsky, Megan E. Paciaroni, Mark A. Linne, James R. Gord, Terrence R. Meyer

Terrence R Meyer

We describe adaptation of ballistic imaging for the liquid core of an atomizing spray. To describe unambiguously the forces that act to break apart the liquid core in a spray, one must directly measure the force vectors themselves. It would be invaluable, therefore, to obtain velocity and acceleration data at the liquid-gas interface. We employ double-image ballistic imaging to extract velocity information through the application of image analysis algorithms. This method is shown to be effective for liquid phase droplet features within the resolution limit of the imaging system. In light of these results, it is clear that a three- …


Minimal Test Collections For Retrieval Evaluation, Ben Carterette, James Allan, Ramesh Sitaraman Jan 2006

Minimal Test Collections For Retrieval Evaluation, Ben Carterette, James Allan, Ramesh Sitaraman

Ramesh Sitaraman

Accurate estimation of information retrieval evaluation metrics such as average precision require large sets of relevance judgments. Building sets large enough for evaluation of real-world implementations is at best inefficient, at worst infeasible. In this work we link evaluation with test collection construction to gain an understanding of the minimal judging effort that must be done to have high confidence in the outcome of an evaluation. A new way of looking at average precision leads to a natural algorithm for selecting documents to judge and allows us to estimate the degree of confidence by defining a distribution over possible document …


A Hierarchical, Hmmbased Automatic Evaluation Of Ocr Accuracy For A Digital Library Of Books, Shaolei Feng, R. Manmatha Dec 2005

A Hierarchical, Hmmbased Automatic Evaluation Of Ocr Accuracy For A Digital Library Of Books, Shaolei Feng, R. Manmatha

R. Manmatha

A number of projects are creating searchable digital libraries of printed books. These include the Million Book Project, the Google Book project and similar efforts from Yahoo and Microsoft. Content-based on line book retrieval usually requires first converting printed text into machine readable (e.g. ASCII) text using an optical character recognition (OCR) engine and then doing full text search on the results. Many of these books are old and there are a variety of processing steps that are required to create an end to end system. Changing any step (including the scanning process) can affect OCR performance and hence a …