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7. Bullet ricochet mark plan-view morphology in concrete: an experimental assessment of five bullet types and two distances using machine learning.

Author

Eren, Metin I, Romans, Jay, Walker, Robert S, Buchanan, Briggs, and Key, Alastair

Subjects
MACHINE learning, BULLETS, INDEPENDENT variables, RANDOM forest algorithms, MORPHOLOGY
Abstract

Bullet ricochets are common occurrences during shooting incidents and can provide a wealth of information useful for shooting incident reconstruction. However, there have only been a small number of studies that have systematically investigated bullet ricochet impact site morphology. Here, this study reports on an experiment that examined the plan-view morphology of 297 ricochet impact sites in concrete that were produced by five different bullet types shot from two distances. This study used a random forest machine learning algorithm to classify bullet types with morphological dimensions of the ricochet mark (impact) with length and perimeter-to-area ratio emerging as the top predictor variables. The 0.22 LR leaves the most distinctive impact mark on the concrete, and overall, the classification accuracy using leave-one-out cross-validation is 62%, considerably higher than a random classification accuracy of 20%. Adding in distance to the model as a predictor increases the classification accuracy to 66%. These initial results are promising, in that they suggest that an unknown bullet type can potentially be determined, or at least probabilistically assessed, from the morphology of the ricochet impact site alone. However, the substantial amount of overlap this study documented among distinct bullet types' ricochet mark morphologies under highly controlled conditions and with machine learning suggests that the human identification of ricochet marks in real-world shooting incident reconstructions may be on occasion, or perhaps regularly, in error. Key points Bullet ricochet impact sites can help with shooting incident reconstruction. A random forest machine learning algorithm classified bullet type from ricochet morphology. Results suggest that unknown bullets can potentially be determined from ricochet impact site morphology. Human identification of bullet types from ricochet sites may be erroneous. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Sexual selection on male vocal fundamental frequency in humans and other anthropoids

Author

Puts, David A., Hill, Alexander K., Bailey, Drew H., Walker, Robert S., Rendall, Drew, Wheatley, John R., Welling, Lisa L. M., Dawood, Khytam, Cárdenas, Rodrigo, Burriss, Robert P., Jablonski, Nina G., Shriver, Mark D., Weiss, Daniel, Lameira, Adriano R., Apicella, Coren L., Owren, Michael J., Barelli, Claudia, Glenn, Mary E., and Ramos-Fernandez, Gabriel

Published
2016

12. Living with Kin in Lowland Horticultural Societies

Author

Walker, Robert S., Beckerman, Stephen, Flinn, Mark V., Gurven, Michael, von Rueden, Chris R., Kramer, Karen L., Greaves, Russell D., Córdoba, Lorena, Villar, Diego, Hagen, Edward H., Koster, Jeremy M., Sugiyama, Lawrence, Hunter, Tiffany E., and Hill, Kim R.

Published
2013
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23. OTA reconsidered

Author

WALKER, ROBERT S., GIBBONS, JOHN H., HERDMAN, ROGER, JONES, ANITA, PALMER, BOB, TEICH, AL, and GUSTON, DAVID H.

Published
2001

24. Budget battles

Author

GIBBONS, JOHN H., GOMORY, RALPH E., GRIFFITHS, PHILLIP A., PRESS, FRANK, METZGER, NORMAN, COOK-DEEGAN, ROBERT MULLAN, and WALKER, ROBERT S.

Published
1996

26. Trim the pork

Author

Walker, Robert S., Rosenzweig, Robert, and Martin, Paul C.

Subjects
Government contract, Research and development contracts, Government -- Economic aspects
Abstract

James Savage's article 'Where's the Pork?' (Issues, Spring 1993) is a timely commentary on the issue of academic pork barrel. His analysis of the various definitions of earmarking clearly and […]

Published
1993

30. The quest for knowledge versus the quest for votes

Author

Walker, Robert S.

Subjects
Science and state -- Analysis, Research -- Finance, Business, Computers, Electronics, Electronics and electrical industries
Abstract

The scientific community needs to develop a closer relationship with the US Congress to raise the level of awareness of legislators to science issues. Most legislators only have a general understanding of popular scientific issues. The scientific community, in developing contacts with legislators, has to convey to them the public benefits of fundamental research. However, it is important for scientists who are asking for government research funds to remember that Congress has to decide on issues based on priority and with regard to the general status of the nation.

Published
1997

31. The need for a Department of Science

Author

Walker, Robert S.

Subjects
Science and state -- Analysis
Abstract

Combining scattered federal research efforts in a single agency would enhance the visibility and the coherence of science programs. As chairman of the House Committee on Science, I have the […]

Published
1995

35. National Climate Program Act—Conference Report

Author

Teague, Olin E., Brown,, George E., Ambro, Jerome, Wirth, Timothy E., Walker, Robert S., Beilenson, Anthony C., Winn,, Larry, Cannon, Howard W., Magnuson, Warren G., Stevenson, Adlai E., Pearson, James B., and Schmitt, Harrison

Published
1978

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