Test method for establishing the cumulative probability of detection for a scanning surveillance radar

1998 ◽  
Author(s):  
Mark S. Clinard
Keyword(s):  
Probability Of Detection ◽  
Test Method ◽  
Cumulative Probability

scholarly journals Multiple Step Interlaced Beam Scan to Minimize the Deviation of Radar Detection Performance

2020 ◽  
Vol 20 (2) ◽  
pp. 125-130
Author(s):  
Ji Hwan Yoon ◽  
Yeonhee Park ◽  
Ji Eun Roh ◽  
Sung Chul Park
Keyword(s):  
Figure Of Merit ◽  
Detection Performance ◽  
Probability Of Detection ◽  
Line Of Sight ◽  
Cumulative Probability ◽  
Search Volume ◽  
Optimal Values ◽  
Fixed Beam ◽  
Beam Lattice ◽  
Multiple Step

For detection of targets, a radar conventionally scans a specified search volume with a fixed beam lattice of a specified beam spacing. With the fixed beam lattice, the detection performance of the radar within a unit beam lattice changes depending on the line-of-sight angle to a target. In this paper, multiple step interlaced scan is proposed to minimize the deviation of the detection performance due to the change of the target line-of-sight angle. As a figure of merit for the detection performance, the cumulative probability of detection is analyzed for various values of the interlaced scan step with different beam overlap ratios, and the optimal values of the steps to minimize the deviation of the cumulative probability of detection are derived.

EVALUATION OF THE ACCURACY OF VOLUMETRIC LEAK DETECTION METHODS FOR UNDERGROUND STORAGE TANKS CONTAINING GASOLINE1

1989 ◽  
Vol 1989 (1) ◽  
pp. 27-35
Author(s):  
Joseph W. Maresca ◽  
James W. Starr ◽  
Robert D. Roach ◽  
John S. Farlow
Keyword(s):  
Data Analysis ◽  
False Alarm ◽  
Leak Detection ◽  
Test Methods ◽  
Probability Of Detection ◽  
Test Method ◽  
Underground Storage ◽  
Storage Tanks ◽  
Test Protocol ◽  
Probability Of False Alarm

ABSTRACT A United States Environmental Protection Agency (EPA) research program evaluated the current performance of commercially available volumetric test methods for the detection of small leaks in underground gasoline storage tanks. The evaluations were performed at the EPA Risk Reduction Engineering Laboratory's Underground Storage Tank Test Apparatus in Edison, New Jersey. The methodology used for evaluation made it possible to determine and resolve most of the technological and engineering issues associated with volumetric leak detection, as well as to define the current practice of commercially available test methods. The approach used (1) experimentally validated models of the important sources of ambient noise that affect volume changes in nonleaking and leaking tanks, (2) a large data base of product-temperature changes that result from the delivery of product to a tank at a different temperature than the product in the tank, and (3) a mathematical model of each test method to estimate the performance of that method. The test-method model includes the instrumentation noise, the configuration of the sensors, the test protocol, the data analysis algorithms, and the detection criterion. Twenty-five commercially available volumetric leak detection systems were evaluated. The leak rate measurable by these systems ranged from 0.26 to 6.78 L/h (0.07 to 1.79 gal/h), with a probability of detection of 0.95 and a probability of false alarm of 0.05. Five methods achieved a performance between 0.19 L/h (0.05 gal/h) and 0.57 L/h (0.15 gal/h). Only one method was able to detect leaks less than 0.57 L/h (0.15 gal/h) if the probability of detection was increased to 0.99 and the probability of false alarm was decreased to 0.01. The measurable leak rates ranged from 0.45 to 12.94 L/h (0.12 to 3.42 gal/h) with these more stringent detection and false alarm parameters. The performance of the methods evaluated was primarily limited by test protocol, operational sensor configuration, data analysis, and calibration, rather than by hardware. The experimental analysis and model calculations suggested that substantial performance improvements can be realized by making procedural changes. With modifications, it is estimated that more than 60 percent of the methods should be able to achieve a probability of detection of 0.99 and a probability of false alarm of 0.01 for leak rates between 0.19 L/h (0.05 gal/h) and 0.56 L/h (0.15 gal/h), and 100 percent should be able to achieve this performance for leak rates of approximately 0.76 L/h (0.20 gal/h).

Impact of Multiple On-Board Inspections on Cumulative Probability of Detection

2005 ◽  
Author(s):  
Brian D. Shook ◽  
Harry R. Millwater ◽  
Michael P. Enright ◽  
Stephen J. Hudak ◽  
William L. Francis
Keyword(s):  
Correlation Coefficient ◽  
Critical Issue ◽  
Step Function ◽  
Probability Of Detection ◽  
Cumulative Probability ◽  
Test Case ◽  
Dramatic Improvement ◽  
Material Defects ◽  
Significant Difference ◽  
Stress Spectrum

The impending application of on-board sensors for detecting and sizing material defects and evaluating their consequences will lead to improved forecasting of readiness, as well as improved safety, retirement-for-cause, and management of assets. This research looks at the consequences of multiple, i.e., continual, on-board inspections on the cumulative probability of detection (CPOD) of the system; that is the probability of detecting a defect considering all previous inspections. In particular, modeling and simulation of the CPOD is examined as a function of the degree of correlation between subsequent inspections. A surface crack in a turbine disk is used as a test case with loading from a typical stress spectrum from a fighter engine. The analysis indicates that a significant difference in detectability is achieved through multiple inspections depending upon the degree of correlation between inspections, with statistically independent inspections exhibiting a “dramatically” improved CPOD over dependent inspections. In particular, if each inspection is statistically independent 1) it is the left tail of the parent POD that defines the CPOD, 2) for the same median value, a higher coefficient of variation of the parent POD generates a significantly more effective CPOD, and 3) if enough inspections are performed, the CPOD curve becomes a step function at the first non-zero value in the parent POD curve, thereby giving orders-of-magnitude improvement in detectibility over the parent POD. The critical issue of statistical independence of multiple inspections is investigated by examining the CPOD as a function of correlation between inspections. The results indicate that the effectiveness of continual inspections on the CPOD varies from a correlation coefficient of zero (independent), which gives a dramatic improvement compared to the parent POD, to a correlation coefficient of one (dependent), which reverts to the parent POD. In summary, the correlation between inspections is a critical component that determines the effectiveness of continual inspections.

Computer Aided Design of Ultrasonic Test by Numerical Simulation

2021 ◽  
Vol 1164 ◽  
pp. 97-104
Author(s):  
Réka Erdei ◽  
Zoltán Bézi ◽  
Csaba Takács
Keyword(s):  
Computer Aided Design ◽  
Grain Orientation ◽  
Ultrasonic Test ◽  
Probability Of Detection ◽  
Test Method ◽  
Dissimilar Metal ◽  
Computer Aided ◽  
Aided Design ◽  
The Given ◽  
Sophisticated Technology

Ultrasonic tests of dissimilar metal welds require extremely sophisticated technology. The complexity of the test is caused by the grain orientation and difficult accessibility of the weld and it is therefore necessary to redound the examinations by simulation. This study details some application possibilities of CIVA software and presents an example of the evaluation of the procedure used for the given test method with probability of detection curves.

Cumulative Detection Probability as a Basis for Pressure Vessel Inspection Intervals

1995 ◽  
Vol 117 (4) ◽  
pp. 399-403 ◽  
Author(s):  
G. Garic
Keyword(s):  
Fracture Mechanics ◽  
Pressure Vessel ◽  
Detection Probability ◽  
Flaw Detection ◽  
Probability Of Detection ◽  
Acceptable Level ◽  
Cumulative Probability ◽  
Failure Risk ◽  
Flaw Detection Probability

This work discusses use of the cumulative flaw detection probability as the basis for establishing pressure vessel inspection intervals. The method is based on the accumulated probability of detecting a flaw over several inspections. It explicitly incorporates a user decision as to the acceptable level of failure risk. A four-step approach is outlined including fracture mechanics flaw growth calculations with probabilistic treatment of detection probability. It is concluded that (a) inspection intervals based on the cumulative probability of detection provide significant advantages over traditional cycle-based methods, (b) pressure vessel recertification inspections should rely on high percentage inspections conducted on a relatively infrequent basis.

Detection of Salmonella species in a Variety of Foods by the DuPont™ BAX® System Real-Time PCR Assay for Salmonella: First Action 2013.02

2014 ◽  
Vol 97 (3) ◽  
pp. 868-875 ◽  
Author(s):  
F Morgan Wallace ◽  
Bridget Andaloro ◽  
Dawn Fallon ◽  
Nisha Corrigan ◽  
Stephen Varkey ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Orange Juice ◽  
Collaborative Study ◽  
Reference Method ◽  
Probability Of Detection ◽  
Test Method ◽  
Pcr Assay ◽  
Test Portion ◽  
Significant Difference

Abstract A multilaboratory study was conducted to evaluate the ability of the DuPont™ BAX® System Real-Time PCR Assay for Salmonella to detect the target species in a variety of foods and environmental surfaces. Internal validation studies were performed by DuPont Nutrition & Health on 24 different sample types to demonstrate the reliability of the test method among a wide variety of sample types. Two of these matrixes—pork and turkey frankfurters and pasteurized, not-from-concentrate orange juice without pulp—were each evaluated in 14 independent laboratories as part of the collaborative study to demonstrate repeatability and reproducibility of the internal laboratory results independent of the end user. Frankfurter samples were evaluated against the U. S. Department of Agriculture, Food Safety and Inspection Service reference method as a paired study, while orange juice samples were evaluated against the U. S. Food and Drug Administration reference method as an unpaired study, using a proprietary media for the test method. Samples tested in this study were artificially inoculated with a Salmonella strain at levels expected to produce low (0.2–2.0 CFU/test portion) or high (5 CFU/test portion) spike levels on the day of analysis. For each matrix, the collaborative study failed to show a statistically significant difference between the candidate method and the reference method using the probability of detection statistical model.

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