A high efficient biometrics approach for unconstrained iris segmentation and recognition

This dissertation develops an innovative approach towards less-constrained iris biometrics. Two major contributions are made in this research endeavor: (1) Designed an award-winning segmentation algorithm in the less-constrained environment where image acquisition is made of subjects on the move and taken under visible lighting conditions, and (2) Developed a pioneering iris biometrics method coupling segmentation and recognition of the iris based on video of moving persons under different acquisitions scenarios. The first part of the dissertation introduces a robust and fast segmentation approach using still images contained in the UBIRIS (version 2) noisy iris database. The results show accuracy estimated at 98% when using 500 randomly selected images from the UBIRIS.v2 partial database, and estimated at 97% in a Noisy Iris Challenge Evaluation (NICE.I) in an international competition that involved 97 participants worldwide involving 35 countries, ranking this research group in sixth position. This accuracy is achieved with a processing speed nearing real time. The second part of this dissertation presents an innovative segmentation and recognition approach using video-based iris images. Following the segmentation stage which delineates the iris region through a novel segmentation strategy, some pioneering experiments on the recognition stage of the less-constrained video iris biometrics have been accomplished. In the video-based and less-constrained iris recognition, the test or subject iris videos/images and the enrolled iris images are acquired with different acquisition systems. In the matching step, the verification/identification result was accomplished by comparing the similarity distance of encoded signature from test images with each of the signature dataset from the enrolled iris images. With the improvements gained, the results proved to be highly accurate under the unconstrained environment which is more challenging. This has led to a false acceptance rate (FAR) of 0% and a false rejection rate (FRR) of 17.64% for 85 tested users with 305 test images from the video, which shows great promise and high practical implications for iris biometrics research and system design.

True and false confessions to an intentional act: A novel experimental paradigm

Due to the powerful nature of confession evidence, it is imperative that we investigate the factors that affect the likelihood of obtaining true and false confessions. Previous research has been conducted with a paradigm limited to the study of false confessions to an act of negligence, thereby limiting the generalizability of the findings. The first goal of the current study was to introduce a novel paradigm involving a more serious, intentional act that can be used in the study of both true and false confessions. The second goal was to explore the effects of two police interrogation tactics, minimization and an offer of leniency, on true and false confession rates. ^ Three hundred and thirty-four undergraduates at a large southeastern university were recruited to participate in a study on problem-solving and decision-making. During the course of the laboratory experiment, participants were induced to intentionally break or not break an experimental rule, an act that was characterized as “cheating.” All participants (i.e., both innocent and guilty) were later accused of the act and interrogated. For half of the participants, the interrogator used minimization tactics, which involved downplaying the seriousness of the offense, expressing sympathy, and providing face-saving excuses, in order to encourage the participant to confess. An offer of leniency was also manipulated in which half the participants were offered a “deal” that involved the option of confessing and accepting a known punishment or not confessing and facing the threat of harsher punishment. Results indicated that guilty persons were more likely to confess than innocent persons, and that the use of minimization and an explicit offer of leniency increased both the true and false confession rates. Furthermore, a cumulative effect of techniques was observed, such that the diagnosticity of the interrogation (the ratio of true confessions to false confessions) decreased as the number of techniques used increased. Taken together, the results suggest that caution should be used when implementing these techniques in the interrogation room. ^

Relative importance of false positives in the selection process

This study investigated the role of contextual factors in personnel selection. Specifically, I explored if specific job factors such as the wage, training, available applicant pool and security concerns around a job, influenced personnel decisions. Additionally, I explored if the individual differences of decision makers played a role in how the previously mentioned job factors affected their decisions. A policy-capturing methodology was employed to determine the weight participants place on the job factors when selecting candidates for different jobs. Regression and correlational analyses were computed with the beta weights obtained from individual regression analyses. The results obtained from the two samples (student and general population) revealed that specific job characteristics did indeed influence personnel decisions. Participants were more concerned with making mistakes and thus less likely to accept candidates when selecting candidates for jobs having high salary and/or high training requirements.

Why Most Biomedical Findings Echoed by Newspapers Turn Out to be False: The Case of Attention Deficit Hyperactivity Disorder

Context: Because positive biomedical observations are more often published than those reporting no effect, initial observations are often refuted or attenuated by subsequent studies. Objective: To determine whether newspapers preferentially report on initial findings and whether they also report on subsequent studies. Methods: We focused on attention deficit hyperactivity disorder (ADHD). Using Factiva and PubMed databases, we identified 47 scientific publications on ADHD published in the 1990s and soon echoed by 347 newspapers articles. We selected the ten most echoed publications and collected all their relevant subsequent studies until 2011. We checked whether findings reported in each ‘‘top 10’’ publication were consistent with previous and subsequent observations. We also compared the newspaper coverage of the ‘‘top 10’’ publications to that of their related scientific studies. Results: Seven of the ‘‘top 10’’ publications were initial studies and the conclusions in six of them were either refuted or strongly attenuated subsequently. The seventh was not confirmed or refuted, but its main conclusion appears unlikely. Among the three ‘‘top 10’’ that were not initial studies, two were confirmed subsequently and the third was attenuated. The newspaper coverage of the ‘‘top 10’’ publications (223 articles) was much larger than that of the 67 related studies (57 articles). Moreover, only one of the latter newspaper articles reported that the corresponding ‘‘top 10’’ finding had been attenuated. The average impact factor of the scientific journals publishing studies echoed by newspapers (17.1 n = 56) was higher (p,0.0001) than that corresponding to related publications that were not echoed (6.4 n = 56). Conclusion: Because newspapers preferentially echo initial ADHD findings appearing in prominent journals, they report on uncertain findings that are often refuted or attenuated by subsequent studies. If this media reporting bias generalizes to health sciences, it represents a major cause of distortion in health science communication.