Low False Rate Research Articles

A hierarchical human detection system in (un)compressed domains

We propose a hierarchical retrieval system where shape, color and motion characteristics of the human body are captured in compressed and uncompressed domains. The proposed retrieval method provides human detection and activity recognition at different resolution levels from low complexity to low false rates and connects low level features to high level semantics by developing relational object and activity presentations. The available information of standard video compression algorithms are used in order to reduce the amount of time and storage needed for the information retrieval. The principal component analysis is used for activity recognition using MPEG motion vectors and results are presented for walking, kicking, and running to demonstrate that the classification among activities is clearly visible. For low resolution and monochrome images it is demonstrated that the structural information of human silhouettes can be captured from AC-DCT coefficients.

Event related brain potentials and illusory memories: the effects of differential encoding

This study investigates event related potentials (ERP) elicited by true and false recognition using words from different semantic categories. In Experiment 1, ERPs for true and false recognition were more positive than for correctly rejected NEW words starting around 300 ms after test word presentation (old/new ERP effects). ERP waveforms for true and false recognition revealed equal early (300–500 ms) fronto-medial old/new ERP effects, reflecting similar familiarity processes, but smaller parietal old/new ERP effects (500–700 ms) for false relative to true recognition, suggesting less active recollection. Interestingly, a subsequent performance based group comparison showed equivalent old/new ERP effects for true and false recognition for participants with high rates of false recognition. In contrast, false recognition failed to elicit an old/new ERP effect in a group with low false recognition rates. To examine whether this between group difference was driven by the differential use of information that studied words and semantically related non studied test words (LURE) have in common (conceptual similarity), we manipulated encoding strategy in Experiment 2. When encoding focused on conceptual similarity, comparable ERP-effects for true and false recognition were obtained, suggesting that both forms of recognition were equally based on familiarity and recollection processes. Conversely, when encoding was focused on item specific features, differences in brain activity for true and false recognition were obtained. The ERP data indicate that, in addition to the false recognition rate, strategic processes during encoding, such as processing conceptual features, are an important factor in determining electrophysiological differences between true and false recognition.

Prediction Accuracy and Financial Savings of Four Screening Tests for a Sequential Test of Clinical Performance

Background: Sequential testing of clinical performance is an effective strategy to reduce cost of testing. Purpose: To evaluate prediction accuracy and financial savings of 4 screening tests of clinical performance. Methods: Screening tests were created from a 13-case examination taken by 434 medical students at 4 schools. Regression analysis determined prediction accuracy for 2 test outcomes. Financial savings were computed from published estimates. Results: Zero false passes were obtained with the "Total Number of Cases Passed" screening test, but it saved only 27%. Sixty-two percent savings with 5% false passes occurred with the "Classification" screening test. The "Scale" and "Mini Test" screening tests would have excused 79% and 67% examinees with 5% and 1% false passes, respectively. Conclusions: Prediction accuracy varies with screening test and outcome measure. Sequential testing of clinical performance can save 40% to 60% with low false pass rates. However, programs need to consider loss of information for curriculum and individual feedback relative to financial savings.

Hyperglycosylated Human Chorionic Gonadotropin (Invasive Trophoblast Antigen) Immunoassay: A New Basis for Gestational Down Syndrome Screening

Serum human chorionic gonadotropin (hCG) and hCG free beta-subunit tests are used in combination with unconjugated estriol and alpha-fetoprotein in the triple screen test, and with the addition of inhibin-A in the quadruple marker test for detecting Down syndrome in the second trimester of pregnancy. These tests have a limited detection rate for Down syndrome: approximately 40% for hCG or free beta-subunit alone, approximately 60% for the triple screen test, and approximately 70% for the quadruple marker test, all at 5%, or a relatively high, false-positive rate. New tests are needed with higher detection and lower false rates. Hyperglycosylated hCG (also known as invasive trophoblast antigen or ITA) is a new test. It specifically detects a unique oligosaccharide variant of hCG associated with Down syndrome pregnancies. We evaluated this new Down syndrome-directed test in prenatal diagnosis. Hyperglycosylated hCG was measured in urine samples from women undergoing amniocentesis for advanced maternal age concerns at 14-22 weeks of gestation, 1448 with normal karyotype and 39 with Down syndrome fetuses. The median hyperglycosylated hCG value was 9.5-fold higher in Down syndrome cases (9.5 multiples of the normal karyotype median). The single test detected 80% of Down syndrome cases at a 5% false-positive rate. Urine hyperglycosylated hCG was combined with urine beta-core fragment (urine breakdown product of serum hCG free beta-subunit), serum alpha-fetoprotein, and maternal age-related risk. This urine-serum combination detected 96% of Down syndrome cases at a 5% false-positive rate, 94% of cases at a 3% false-positive rate, and 71% of cases at a 1% false-positive rate. These detection rates exceed those of any previously reported combination of biochemical markers. Hyperglycosylated hCG is a new base marker for Down syndrome screening in the second trimester of pregnancy. The measurement of hyperglycosylated hCG can fundamentally improve the performance of Down syndrome screening protocols.

Digital Signal Processing for Optical Particle Counters in Order to Improve the Signal-to-Noise Ratio

ABSTRACT Especially In clean technology optical particle counters with high flow rates, low detection limits with respect to particle size and a low false count rate are needed. The lower detection limit and the false count rate can be reduced if the SNR can be increased. In this paper, we present a method to increase the SNR for any given optical particle counter using electronics means. First, the process of signal formation is investigated and the quantities determining the signal are described. The task is then to extract the particle pulses from the mixture of signals. Current methods for signal detection are briefly described. Using the signal theory, a correlation receiver is designed which provides a maximum SNR at the filter exit. This receiver has built-in digital technology. It offers the possibility of on-line filtering of particle signals. The results show a distinct improvement of the SNR. The actual value is different for each individual optical particle counter. In the case of the clean ro...

The Credibility of Drug Tests: A Multi-Stage Bayesian Analysis

The authors show that even when drug tests are extremely accurate by conventional measures, under some circumstances they will yield a high “false accusation rate” (that is, a high percentage of those testing positive for drugs will not have drugs in their systems). For example, if a drug-testing process that produces only one false positive per 2,000 drug-free specimens, and no false negatives, is administered to a population in which 0.1% of the people use the targeted drugs, one-third of those identified as drug users will be falsely accused. The authors propose a multi-stage Bayesian algorithm—an approach commonly used in management science but novel to industrial relations—that assures that a drug-testing process will have a low enough false accusation rate to provide credible evidence of drug use. They also identify other types of employee evaluations to which Bayesian modeling could be applied.

Improved salvage of complicated microvascular transplants monitored with quantitative fluorometry.

Quantitative fluorometry has been used to monitor circulation in transplanted toes and cutaneous flaps in our unit since 1982. Analysis of 177 uncomplicated transplants monitored by quantitative fluorometry shows that this technique has low false indication rates for arterial occlusion (0.6 percent of patients) and venous occlusion (6.2 percent of patients). None of these patients was reexplored because of a false monitor reading, and except for single abnormal sequences, monitoring appropriately indicated intact circulation throughout the postoperative period. Quantitative fluorometry has correctly indicated vascular complications in 21 (91.3 percent) of 23 transplants over an 8-year period. The salvage rate (85.7 percent) of the fluorescein-monitored reexplored transplants was significantly higher than the salvage rates of similar reexplored transplants not monitored with fluorescein and of reexplored muscle flaps (which cannot be monitored with the fluorometer used at this unit). These clinical data indicate that quantitative fluorometry is a valid and useful postoperative monitor for transplanted toes and cutaneous flaps.

An evaluation of some design metrics

The paper attempts to evaluate some software design metrics, using data from a communications system. The design metrics investigated were based on the information flow metrics proposed by Henry and Kafura, and the problems they encountered are discussed. The slightly simpler metrics used in this study are described. The ability of the design metrics to identify change-prone, error-prone and complex programs was contrasted with that of simple code metrics. Although one of the design metrics (informational fan-out) was able to identify change-prone, fault-prone and complex programs, code metrics (i.e. lines of code and number of branches) were better. In this context ‘better’ means correctly identifying a larger proportion of change-prone, error-prone and/or complex programs, while maintaining a relatively low false identification rate (i.e. incorrectly identifying a program which did not in fact exhibit any undesirable features).

Face recognition, pose and ecological validity

AbstractThis paper describes five experiments with two main aims; first, to assess the effects of variations in photographic facial pose on recognizability. A second, more fundamental aim was to examine the reliability of laboratory findings relevant to face recognition, in more ecologically valid settings, and to develop a methodology to further this aim. In Experiment 1 best performance was achieved with provision of three facial poses, namely full‐face, three‐quarter and profile views. With a single pose a three‐quarter view was the most helpful. Experiments 2 and 3 attempted to evaluate these findings in a real‐life setting using the general public or paid volunteers who attempted to identify a live target in a town centre from a previously presented photograph. The general public produced a very poor response, and the volunteers produced a low detection and high false recognition rate. Experiment 4 increased constraints on the experimental environment and produced a reasonable hit rate, but no effects of pose. Experiment 5 was a laboratory study where the presentation of a live target preceded photographic recognition. Effects of pose reappeared in line with results of Experiment 1. These results underline the danger involved in making practical recommendations arising from purely laboratory based research.