False Negative Matches Research Articles

Seals from outer space - Population census of southern elephant seals using VHR satellite imagery

This work aims to assess the utility of World-View 3 satellite imagery of 31 cm resolution for conducting population censuses of southern elephant seals (SES). For the first time, we present a comparison of the results of image analyses of a 31 cm resolution satellite image and 1.39 cm resolution drone-based orthophoto of a SES breeding colony located at Patelnia Point (King George Island, breeding season 2019). The time distance separating both visualisations of the same area was 15 h 4 min, which allowed us to determine the female recognition from the VHR image with an error of 1.5–7.0%, depending on the density of females in the breeding formation. An important component of this error is false negative matches, which can have a significant impact when selecting the objects needed to train deep learning models. In addition, the pup recognition error was much higher and was 24.6–40.2%, which depended on the density of animals in harems, a large variation in the size of the pups and the diverse substrate on which they were deposited. Counting on VHR images was performed manually by eleven observers familiar with the morphological characteristics of SES. The resolution of the VHR photo allows the identification of females and males involved in breeding due to the clear dimorphism of their sizes. We recommend using VHR satellite imagery to determine the number of breeding formations and spatial relationships between them, as well as for counting females and males during the breeding haul-out. The resolution of satellite imagery available at this time is still insufficient to be used to determine breeding success. With increasing access to satellite resources and an ever-expanding database of VHR images, this is a promising tool to fill the gaps in knowledge about the global population of SESs.

Forensic personal identification utilizing part-to-part comparison of CT-derived 3D lumbar models

The objective of this project was to document the efficacy of part-to-part comparison of computed tomography (CT)-derived three-dimensional (3D) models of the lumbar spine in forensic personal identification. By testing the methodology, this study aimed to provide a new technique of quantifiable (through a percent match) positive identification that meets the explicit requirements of the Daubert ruling and the challenges set forth in the 2009 NAS report. Ante-mortem (AM) and simulated post-mortem (PM) models of the lumbar vertebrae (L1–L5) for 30 unique individuals were compared via part comparison analyses. The threshold of ±0.5mm with at least a 90% match was considered a positive identification. Using this threshold, the part comparison results had a perfect identification rate with no false positives and no false negative matches. A ROC curve was generated with a score of 1, signifying a “perfect” sensitivity and specificity, at a cut-off value of 65.5%. On average positive IDs had a 94.7% percent match within the established threshold, while negative IDs had an average of 21.4%. In looking at the impact of different components of the biological profile, age and sex of the unknown individual played a minimal role in the percent match for both a positive and a negative ID. Lumbar level also played a minor role in in both the positive and negative percent match. The real-world application of 3D part-to-part comparison on AM and simulated PM scans demonstrate the potential usefulness of this technology in forensic identification.

Bite Marks Analysis Using Computer Assisted Hand Tracing Overlay Method

Background : In resent years, crime rate has been increased. The aim of this study was to evaluate the computer assisted hand tracing overlay method for bite mark analysis. Methods: Impressions of both, maxillary as well as mandibular arches of 50 consenting volunteers were taken and dentition casts were prepared. Tracing by hand was manually done, and computer assisted overlay comparison was carried out. Results: Out of 2500 cross matches, expected result should have been 50 true positives and 2450 true negatives. In our study there were 38 true positive, 2406 true negatives, 44 false positive and 12 false negative matches in maxillary comparison, 44 true positive, 2424 true negatives, 26 false positive and 6 false negative matches in mandibular comparison and 31 true positive, 2446 true negatives, 4 false positive and 19 false negative matches when complete dentition (maxillary and mandibular) comparison was done. Hence this method showed significantly high false positive and true negative cases. Conclusion: We conclude that this computer assisted hand tracing overlay method for bite mark analysis helps in arriving at an exclusion rather than inclusion type of identification, owing to its high true negative cases.

A new method for assessing how sensitivity and specificity of linkage studies affects estimation.

BackgroundWhile the importance of record linkage is widely recognised, few studies have attempted to quantify how linkage errors may have impacted on their own findings and outcomes. Even where authors of linkage studies have attempted to estimate sensitivity and specificity based on subjects with known status, the effects of false negatives and positives on event rates and estimates of effect are not often described.MethodsWe present quantification of the effect of sensitivity and specificity of the linkage process on event rates and incidence, as well as the resultant effect on relative risks. Formulae to estimate the true number of events and estimated relative risk adjusted for given linkage sensitivity and specificity are then derived and applied to data from a prisoner mortality study. The implications of false positive and false negative matches are also discussed.DiscussionComparisons of the effect of sensitivity and specificity on incidence and relative risks indicate that it is more important for linkages to be highly specific than sensitive, particularly if true incidence rates are low. We would recommend that, where possible, some quantitative estimates of the sensitivity and specificity of the linkage process be performed, allowing the effect of these quantities on observed results to be assessed.

Virtual Tool Mark Generation for Efficient Striation Analysis,

This study introduces a tool mark analysis approach based upon 3D scans of screwdriver tip and marked plate surfaces at the micrometer scale from an optical microscope. An open-source 3D graphics software package is utilized to simulate the marking process as the projection of the tip's geometry in the direction of tool travel. The edge of this projection becomes a virtual tool mark that is compared to cross-sections of the marked plate geometry using the statistical likelihood algorithm introduced by Chumbley et al. In a study with both sides of six screwdriver tips and 34 corresponding marks, the method distinguished known matches from known nonmatches with zero false-positive matches and two false-negative matches. For matches, it could predict the correct marking angle within ±5-10°. Individual comparisons could be made in seconds on a desktop computer, suggesting that the method could save time for examiners.

Testing an alternative search algorithm for compound identification with the ‘Wiley Registry of Tandem Mass Spectral Data, MSforID’

A tandem mass spectral database system consists of a library of reference spectra and a search program. State-of-the-art search programs show a high tolerance for variability in compound-specific fragmentation patterns produced by collision-induced decomposition and enable sensitive and specific 'identity search'. In this communication, performance characteristics of two search algorithms combined with the 'Wiley Registry of Tandem Mass Spectral Data, MSforID' (Wiley Registry MSMS, John Wiley and Sons, Hoboken, NJ, USA) were evaluated. The search algorithms tested were the MSMS search algorithm implemented in the NIST MS Search program 2.0g (NIST, Gaithersburg, MD, USA) and the MSforID algorithm (John Wiley and Sons, Hoboken, NJ, USA). Sample spectra were acquired on different instruments and, thus, covered a broad range of possible experimental conditions or were generated in silico. For each algorithm, more than 30,000 matches were performed. Statistical evaluation of the library search results revealed that principally both search algorithms can be combined with the Wiley Registry MSMS to create a reliable identification tool. It appears, however, that a higher degree of spectral similarity is necessary to obtain a correct match with the NIST MS Search program. This characteristic of the NIST MS Search program has a positive effect on specificity as it helps to avoid false positive matches (type I errors), but reduces sensitivity. Thus, particularly with sample spectra acquired on instruments differing in their setup from tandem-in-space type fragmentation, a comparably higher number of false negative matches (type II errors) were observed by searching the Wiley Registry MSMS.

Codestream-Based Identification of JPEG 2000 Images with Different Coding Parameters

A method of identifying JPEG 2000 images with different coding parameters, such as code-block sizes, quantization-step sizes, and resolution levels, is presented. It does not produce false-negative matches regardless of different coding parameters (compression rate, code-block size, and discrete wavelet transform (DWT) resolutions levels) or quantization step sizes. This feature is not provided by conventional methods. Moreover, the proposed approach is fast because it uses the number of zero-bit-planes that can be extracted from the JPEG 2000 codestream by only parsing the header information without embedded block coding with optimized truncation (EBCOT) decoding. The experimental results revealed the effectiveness of image identification based on the new method.

An Empiric Modification to the Probabilistic Record Linkage Algorithm Using Frequency-Based Weight Scaling

ObjectiveTo incorporate value-based weight scaling into the Fellegi-Sunter (F–S) maximum likelihood linkage algorithm and evaluate the performance of the modified algorithm. BackgroundBecause healthcare data are fragmented across many healthcare systems, record linkage is a key component of fully functional health information exchanges. Probabilistic linkage methods produce more accurate, dynamic, and robust matching results than rule-based approaches, particularly when matching patient records that lack unique identifiers. Theoretically, the relative frequency of specific data elements can enhance the F–S method, including minimizing the false-positive or false-negative matches. However, to our knowledge, no frequency-based weight scaling modification to the F–S method has been implemented and specifically evaluated using real-world clinical data. MethodsThe authors implemented a value-based weight scaling modification using an information theoretical model, and formally evaluated the effectiveness of this modification by linking 51,361 records from Indiana statewide newborn screening data to 80,089 HL7 registration messages from the Indiana Network for Patient Care, an operational health information exchange. In addition to applying the weight scaling modification to all fields, we examined the effect of selectively scaling common or uncommon field-specific values. ResultsThe sensitivity, specificity, and positive predictive value for applying weight scaling to all field-specific values were 95.4, 98.8, and 99.9%, respectively. Compared with nonweight scaling, the modified F–S algorithm demonstrated a 10% increase in specificity with a 3% decrease in sensitivity. ConclusionBy eliminating false-positive matches, the value-based weight modification can enhance the specificity of the F–S method with minimal decrease in sensitivity.

Recommended Steps for a FASTA Search

INTRODUCTIONThe following strategy is recommended for searches with FASTA for finding the most homologous sequences in a database search while avoiding false-negative matches.

Application of Capture-Recapture Methods for Disease Monitoring: Potential Effects of Imperfect Record Linkage

Capture-recapture methods are increasingly employed to correct for underascertainment of cases in disease monitoring. Routine systems of disease monitoring, such as morbidity registries, are often prone to specific threats of validity, such as in imperfect diagnoses or imperfect record linkage. A quantitative assessment is given of the performance of the two-source capture-recapture method for disease monitoring in the presence of imperfect record linkage. The capture-recapture approach can eliminate underestimation of the number of eligible cases, which is typical for most disease monitoring systems, under certain conditions, including independence of sources of case ascertainment and perfect record linkage. Correction for underestimation remains less than perfect, however, in the case of false-positive matches, whereas application of capture-recapture methods leads to overestimation of case numbers in the presence of false-negative matches. A simple correction procedure to overcome potential overestimation by false-negative matches is outlined.