A Robust User Authentication Technique in Online Examination

Currently user authentication and identity monitoring are required in various collaborative computer supported systems, such as online assessments and examinations. However, existing authentication methods such as passwords checking are less reliable. In addition, identity monitoring is hard to be realized effectively and efficiently for applications based on collaborative architecture. In this paper, we leverage keystroke dynamics to explore biometrics security and propose a user authentication framework based on edge computing architecture to address these issues. To support both static and continuous authentications with high accuracy and efficiency, dynamically improved keystroke profiles, Gaussian model based anomaly detector and keystroke stream processing are designed in the framework. The feasibility and effectiveness of the framework are verified by three representative public data sets and a real-world case study. The results show that the authentication can proceeds efficiently to enable an undisturbed and secure environment for online examinations.

UIPA: User authentication method based on user interface preferences for account recovery process

Motivation: Certain studies use short-TE MRS to estimate metabolites such as gamma-aminobutyric acid. The findings of such studies hinge on the correlation of this technique to the gold-standard edited MRS technique. Goal(s): We investigate how the false negative rate and false positive rate of studies vary as a function of correlation between short-TE and MEGA-edited metabolite estimates. Approach: Simulated data was used to numerically estimate the false positive and false negative rates, using parameters obtained from the literature. Results: We show that these studies can have largely inflated false positive and false negative rates as compared to their nominally designed values. Impact: The false negative and false positive rate can be markedly inflated when using short-TE MRS to estimate metabolites such as gamma-aminobutyric acid. This calls for increased caution in interpreting results, and the accommodation of these effects when designing statistical analyses.

Ranaviruses have been identified as the etiologic agent in many amphibian die-offs across the globe. Polymerase chain reaction (PCR) is commonly used to detect ranavirus infection in amphibian hosts, but the test results may vary between tissue samples obtained by lethal and non-lethal procedures. Testing liver samples for infection is a common lethal sampling technique to estimate ranavirus prevalence because the pathogen often targets this organ and the liver is easy to identify and collect. However, tail clips or swabs may be more practicable for ranavirus surveillance programs compared with collecting and euthanizing animals, especially for uncommon species. Using PCR results from liver samples for comparison, we defined false-positive test results as occurrences when a non-lethal technique indicated positive but the liver sample was negative. Similarly, we defined false-negative test results as occurrences when a non-lethal technique was negative but the liver sample was positive. Using these decision rules, we estimated false-negative and false-positive rates for tail clips and swabs. Our study was conducted in a controlled facility using American bullfrog Lithobates catesbeianus tadpoles; false-positive and false-negative rates were estimated after different periods of time following exposure to ranavirus. False-negative and false-positive rates were 20 and 6%, respectively, for tail samples, and 22 and 12%, respectively, for swabs. False-negative rates were constant over time, but false-positive rates decreased with post-exposure duration. Our results suggest that non-lethal sampling techniques can be useful for ranavirus surveillance, although the prevalence of infection may be underestimated when compared to results obtained with liver samples.

The Effect of Testing Reliability on Visual Field Sensitivity in Normal Eyes: The Singapore Chinese Eye Study

Machine learning and deep learning for user authentication and authorization in cybersecurity: A state-of-the-art review

To evaluate the false-negative and false-positive error rates both in a screening and a non-screening population. A total of 4192 prostatic biopsies were reported in a 6-year period by 15 consultant histopathologists, two of whom had an interest in uropathology and were deemed to be specialists (J.O. and C.S.). All biopsies were reviewed prior to the multidisciplinary team (MDT) meeting. The overall false-negative rate was 1.7% (screening 2.1%, non-screening 1.5%). The overall false-positive rate was 0.5% (screening 0.9%, non-screening 0.4%). These error rates varied among pathologists, with the false-negative rate ranging from 0% to 9.3%, and the false-positive rate ranging from 0% to 3.8%. The false-negative rate was three times greater than the false-positive rate, showing that detection of significant pathology is far greater in the negative biopsies. More errors occurred in the screening population than in the non-screening population. The consultants making the most errors were non-specialists, but the specialists also made false-negative errors, suggesting that just using specialist reporting alone would not have eradicated errors.

Biometric-based authentication systems are becoming the preferred choice to replace password-based authentication systems. Among several variations of biometrics (e.g., face, eye, fingerprint), iris-based authentication is commonly used in every day applications. In iris-based authentication systems, iris images from legitimate users are captured and certain features are extracted to be used for matching during the authentication process. Literature works suggest that iris-based authentication systems can be subject to presentation attacks where an attacker obtains printed copy of the victim’s eye image and displays it in front of an authentication system to gain unauthorized access. Such attacks can be performed by displaying static eye images on mobile devices or iPad (known as screen attacks). As iris features are not changed, once an iris feature is compromised, it is hard to avoid this type of attack. Existing approaches relying on static features of the iris are not suitable to prevent presentation attacks. Feature from live Iris (or liveness detection) is a promising approach. Further, additional layer of security from iris feature can enable hardening the security of authentication system that existing works do not address. To address these limitations, this chapter introduces iris signature generation based on the area between the pupil and the cornea. Our approach relies on capturing iris images using near infrared light. We train two classifiers to capture the area between the pupil and the cornea. The image of iris is then stored in the database. This approach generates a QR code from the iris. The code acts as a password (additional layer of security) and a user is required to provide it during authentication. The approach has been tested using samples obtained from publicly available iris database. The initial results show that the proposed approach has lower false positive and false negative rates.

An Evaluation of Conventional Culture, invA PCR, and the Real-Time PCR iQ-Check Kit as Detection Tools for Salmonella in Naturally Contaminated Premarket and Retail Turkey

The influence of fatigue and related factors on automated perimetric testing was evaluated in both eyes of sixteen normal observers and sixteen patients with early-to-moderate visual field loss using a Digilab 750 automated perimeter and a customized test procedure. False positive rate, false negative rate, and detection sensitivity at 5,10,15, and 20 degrees eccentricity were measured in 1.5-rain intervals throughout a 21-min visual field examination. Half of the normal observers and patients with visual field loss were given a briefrest(1.5-min) midway through each visual field exam to determine whether this would reduce fatigue effects. Our findings revealed that patients displayed considerably higher average false positive and false negative rates than normal observers. However, neither the patients nor normal observers demonstrated any consistent changes in false positive rate or false negative rate as a function of testing duration. In contrast, both normal observers and patients showed an average decrease in sensitivity as a function of increasing test duration with the magnitude of the time-dependent sensitivity loss becoming greater with increasing stimulus eccentricity. Patients demonstrated a larger time-dependent sensitivity loss than normal observers, averaging ~4dB at 20 degrees eccentricity. The introduction of a brief pause midway through the test procedure appeared to reduce the time-dependent sensitivity loss for the second half of the test procedure, especially for greater eccentricities.

Several different types of detectors, software, and hardware designs are employed in instruments used to monitor radioactive content of freight shipments in order to detect illicit trafficking of nuclear materials. The instruments can be container monitors, hand-held radiation detectors, mobile analysis systems, or fixed radiation portal monitors. However, within the various groupings (e.g., portal monitors), all instruments are expected to solve the same problem, that is, to detect and identify any radioactive material present according to the prescribed investigative procedure or CONOPS. The best way to compare the performance of different instruments is with a numerical score or Figure of Merit (FOM). The FOM must quantify the performance of the instrument with respect to true positives (TP), false positives (FP), and false negatives (FN). The minimization of FN for certain radionuclides (e.g., uranium and plutonium or other Special Nuclear Material (SNM)) is more important than the minimization of FN for non-threat nuclides (e.g., low level NORM). In a similar way, the minimization of FP for SNM is more important than falsely reporting the common NORM nuclides which represent no threat. System performance depends on the measurement detail (e.g., transit speed through a portal, measurement time in general, amount and distribution of NORM), therefore the test conditions should also be included in the statement of the FOM. The FOM is expected to vary significantly with the above measurement details. A FOM has been developed based on the number of true positives (TP), the number of false important positives (FIP), the number of FP, the number of true positives for SNM (TPSNM), and the number of false positives for SNM (FPSNM). This formula rates the overall performance with extra weight given to FP and FN for SNM. Examples will be shown for testing of portal monitors.

Relationships between age and visual field (VF) reliability indices were investigated using a large real-world dataset (42,421 VF data points from 11,525 eyes of 5930 subjects). All VFs tested and stored at Shimane University Hospital between 1988 and 2019 were exported. Correlations between age, mean deviation (MD), pattern standard deviation (PSD), and reliability indices including fixation losses (FLs), false negatives (FNs), and false positives (FPs) were analyzed. The mean ± standard deviation age was 65.0 ± 15.1 years; MD—−6.9 ± 8.1 decibels (dB); PSD—6.3 ± 4.6 dB; FL—8.6 ± 11.7%; FN—5.3 ± 8.3%; and FP—2.6 ± 5.0%. Univariate analyses showed strong associations between age and FNs (correlation coefficient, ρ = 0.20, p < 0.0001) and MD (ρ = −0.21, p < 0.0001). All FLs, FNs, and FPs were lowest during the third decade (20–29 years) of life. FLs were elevated consistently after that decade, and FNs were elevated sharply after the seventh decade. FPs were relatively stable after the fourth decade (30–39 years). Mixed-effect regression analyses in subjects 40 years and older showed that older age was associated with worse FLs (p < 0.0001) and FNs (p < 0.0001) but not FPs (p = 0.4126). Aging affects FLs and FNs with different modes but had minimal effects on FPs. Decreased VF sensitivity, deteriorated macular function, and technical difficulties with testing may be mechanisms of age-related changes in FLs and FNs.

How do we make the best choice in assays used to monitor HLA antibodies in renal recipients awaiting transplant? A comparison of flowpra beads with luminex single-antigen beads

This study aimed to compare the results of the IMO vifa 24plus(1-2) and HFA 24-2 visual field tests. We included 52 patients (104 eyes) with glaucoma who visited Chukyo Eye Clinic between June 2023 and March 2024. On the same day, the HFA 24-2 test using the Swedish Interactive Threshold Algorithm Standard and the IMO vifa 24plus(1-2) test using the Ambient Interactive Zippy Estimated strategy were performed. A Wilcoxon signed-rank test was used to compare fixation, false positives, false negatives, and total test time for both eyes between the HFA and IMO vifa tests. Only eyes with reliable test results were selected, and the visual field index (VFI), mean deviation (MD), and pattern standard deviation (PSD) were examined using Spearman's rank correlation coefficient and the Wilcoxon signed-rank test. The test times for the HFA 24-2 and IMO vifa 24plus(1-2) were 716.83±118.80 and 628.75±142.70 s, respectively, with the IMO vifa being significantly shorter (P<0.001). For fixation, the results were 15.85±16.57% and 11.09±15.20%, with significantly better fixation in the IMO vifa (P<0.0001). False positives and negatives were 4.52±5.19 / 4.14±6.85% and 4.97±7.99 / 5.47±7.86%, respectively, with no significant differences, though the IMO vifa showed a slightly higher trend (P=0.980, 0.056). In eyes with reliable results, the HFA 24-2 and IMO vifa 24plus(1-2) outcomes were as follows: MD (-6.45±7.23, -6.85±7.35, P=0.724), PSD (7.13±4.75, 7.49±4.87, P=0.061), VFI (80.86±21.61, 80.86±21.74, P=0.644). The Spearman rank correlation coefficients between the HFA 24-2 and IMO vifa 24plus(1-2) were MD: 0.938, PSD: 0.949, VFI: 0.932 (all P<0.001). The IMO vifa demonstrates a very high correlation with HFA and allows for a shorter examination time. Fixation errors are significantly improved compared to HFA, while there is no significant difference in false positives or false negatives.

In many online examinations, physical invigilation is often replaced with traditional authentication approaches for student identification. Secure and usable authentication approaches are important for high stake online examinations. A Profile Based Authentication Framework (PBAF) was developed and implemented in a real online learning course embedded with summative online examination. Based on users' experience of using the PBAF in an online course, online questionnaires were used to collect participants' feedback on effectiveness, layout and appearance, user satisfaction, distraction and privacy concerns. Based on overall findings of the quantitative analysis, there was a positive feedback on the use of a hybrid approach utilizing image and text based challenge questions for better usability. However, the number of questions presented during learning and examination processes were reported to be too many and caused distraction. Participants expressed a degree of concern on sharing personal and academic information with little or no privacy concern on using favorite questions (p < 0.01).