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Engineering Aviation Security Environments—Reduction of False Alarms in Computed Tomography-Based Screening of Checked Baggage (2013) / Chapter Skim
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D--Statistical Approaches to Reducing the Probability of False Alarms While Improving the Probability of Detection
Pages 81-85

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 81...
... The main assumption is that each time the bag passes through the CT scanner, it provides a different scan. This is reasonable because the bag almost certainly will get positioned somewhat differently at each pass because of the bumps on the conveyor belt.
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From page 82...
... Hypothesis 2: The bag is a threat. Given: Y, the number of times out of N the bag is declared a threat by the CT scanner Statistical Model It is obvious that (a)
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From page 83...
... 2 Ian Hacking, The Logic of Statistical Inference, Cambridge University Press, Cambridge, U.K., 1965; Richard M Royall, Statistical Evidence: A Likelihood Paradigm, Capman and Hall, New York, 1997; Mark L
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From page 84...
... The difference between the evidential approach and the NP approach is this: In the evidential paradigm the cut-off point is determined a priori and the error probabilities are calculated afterwards, whereas in the NP approach, the error probabilities are fixed a priori and the cut-off points are determined afterwards. In this particular situation, the author does not see any difference between following the NP approach or the evidential approach.
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From page 85...
... However, there are limits as to how much CT scanning technology and the feature detection algorithms can increase the probability of detection. The repeated scanning approach takes the current technology and significantly increases the probability of detection and decreases the probability of false alarm without requiring significant technological breakthroughs.
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Key Terms

  • evidential approach
  • false alarm
  • statistical inference
  • false positive
  • hand inspection

  • decision rule
  • threat exists
  • false positives
  • typical entry
  • error probabilities

  • versus simple
  • detection probability
  • correct detection
  • simple versus
  • duxbury press

  • true threat
  • five scans
  • feature recognition
  • feature detection
  • misleading evidence

  • detection depends
  • human screeners
  • significant technological
  • significantly increases
  • data support

  • conditional probability
  • repeated scanning
  • alarm rate
  • cited approximate
  • multiple scans


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