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Search Publications by: Craig M. Shakarji (Fed)

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Displaying 26 - 50 of 55

Evaluating CT for Metrology: The Influence of Material Thickness on Measurements

October 7, 2014
Author(s)
Joseph Schlecht, Eric Ferley, Shaun COUGHLIN , Steven D. Phillips, Vincent Lee, Craig M. Shakarji
X-ray imaging provides a non-destructive means to measure internal features of a workpiece, and CT offers unique capabilities for internal measurements in 3-D. However, due to the computational nature of CT and its indirect measurement process, assessing

An improved L1 based algorithm for standardized planar datum establishment

October 1, 2014
Author(s)
Craig M. Shakarji, Vijay Srinivasan
This paper has two major goals. First, we present an algorithm for establishing planar datums suitable for a default in tolerancing standards. The algorithm is based on a constrained minimization search based on the L_1 (L1) norm after forming a convex

Common-Path Method for Laser Tracker Ranging Calibration

March 31, 2014
Author(s)
Christopher J. Blackburn, Daniel S. Sawyer, Craig M. Shakarji
We present an alternative to the back-to-back method of testing laser tracker ranging systems. Our approach uses a common air path for both the measurement and reference laser beams. This technique allows for more accurate determination of the reference

Metrological challenges introduced by new tolerancing standards

February 13, 2014
Author(s)
Ed Morse, Yue Peng, Vijay Srinivasan, Craig M. Shakarji
The recent release of ISO has provided designers with a richer set of specification tools for the size of part features, so that various functional requirements can be captured with greater fidelity [2]. However, these tools also bring new challenges and

Metrological Challenges Introduced by New Tolerancing Standards

July 5, 2013
Author(s)
Ed Morse, Yue Peng, Vijay Srinivasan, Craig M. Shakarji
The recent release of ISO 14405-1 has provided designers with a richer set of specification tools for the size of part features, so that various functional requirements can be captured with greater fidelity. However, these tools also bring new challenges

Choosing test positions for laser tracker evaluation and future Standards development

July 15, 2010
Author(s)
Balasubramanian Muralikrishnan, Daniel S. Sawyer, Christopher J. Blackburn, Steven D. Phillips, Craig M. Shakarji, Ed Morse, Robert Bridges
A working group within the ISO TC 213 committee is developing a draft document [11] for evaluating the performance of laser trackers. The ASME B89.4.19 Standard [1] and the draft VDI/VDE 2617 part 10 [2] describe some useful tests that are incorporated

RECIST vs. Volume Measurement in Medical CT Using Ellipsoids of Known Size

April 12, 2010
Author(s)
Zachary H. Levine, Bruce R. Borchardt, Nolan J. Brandenburg, Charles W. Clark, Balasubramanian Muralikrishnan, Craig M. Shakarji, Joseph J. Chen, Eliot L. Siegel
(a) Purpose: We wanted to test the extent to which two common methods of determining the sizes of tumors would perform when compared to a statistically significant number of well-characterized reference objects. The size of the objects was chosen to

Dimensional measurement traceability of 3D imaging data

January 19, 2009
Author(s)
Steven D. Phillips, Craig M. Shakarji, Michael Krystek, K Summerhays
This paper discusses the concept of metrological traceability to the SI unit of length, the meter. We describe how metrological traceability is realized, give a recent example of the standardization of laser trackers, and discuss progress and challenges to

Calibration of a Computer Assisted Orthopedic Hip Surgery Phantom

November 4, 2008
Author(s)
Daniel S. Sawyer, Nicholas G. Dagalakis, Craig M. Shakarji, Yong Sik Kim
Orthopedic surgeons have identified a need for calibration artifacts (phantoms) to establish the traceability (to the SI unit of length) of measurements performed with Computer Assisted Orthopedic Surgery (CAOS) systems. These phantoms must be lightweight

Spot Weld Analysis with Two-Dimensional Ultrasonic Arrays

January 1, 2004
Author(s)
D A. Denisov, Craig M. Shakarji, R G. Maev, J M. Paille, B B. Lawford
This paper describes a threefold method of testing the performance of an array-based ultrasonic tool for nondestructive testing of spot welds. The tool is described in its capabilities, use, and advantages over existing counterparts. Performance testing is

Should You Be Concerned with Software Measurement Uncertainty?

August 1, 2003
Author(s)
Craig M. Shakarji, J D. Raffaldi
The contribution of software to the uncertainty of measurements is an important but often overlooked aspect of uncertainty evaluations. In coordinate metrology, software is often relied upon for complicated fitting of data, filtering, calibrations, and
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