New cognitive deep-learning CAPTCHA

CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart), or HIP (Human Interactive Proof), has long been utilized to avoid bots manipulating web services. Over the years, various CAPTCHAs have been presented, primarily to enhance security and usability against new bots and cybercriminals carrying out destructive actions. Nevertheless, automated attacks supported by ML (Machine Learning), CNN (Convolutional Neural Network), and DNN (Deep Neural Network) have successfully broken all common conventional schemes, including text- and image-based CAPTCHAs. CNN/DNN have recently been shown to be extremely vulnerable to adversarial examples, which can consistently deceive neural networks by introducing noise that humans are incapable of detecting. In this study, the authors improve the security for CAPTCHA design by combining text-based, image-based, and cognitive CAPTCHA characteristics and applying adversarial examples and neural style transfer. Comprehend usability and security assessments are performed to evaluate the efficacy of the improvement in CAPTCHA. The results show that the proposed CAPTCHA outperforms standard CAPTCHAs in terms of security while remaining usable. Our work makes two major contributions: first, we show that the combination of deep learning and cognition can significantly improve the security of image-based and text-based CAPTCHAs; and second, we suggest a promising direction for designing CAPTCHAs with the concept of the proposed CAPTCHA.Web of Science234art. no. 233

Managing egress of crowd during infrastructure disruption

National Research Foundation (NRF) Singapore under Corp Lab @ University schem

Improvement of traditional shrimp culture in the Mekong Delta

Improvements to traditional brackishwater shrimp culture in the Mekong Delta, Vietnam are discussed. A technical support program has been implemented based on a so-called improved extensive shrimp culture method, as previously developed and tested by the Artermia and Shrimp Research and Development Center (ASRDC). The program focuses on: 1) the use of hatchery-produced postlarvae (of Penaeus monodon and P. merguinensis) nursed for three to four weeks, and 2) the application of low-cost pond management practices including predator control, supplementary feeding and frequent water renewal. A credit program, managed as a revolving fund was made available. A dialogue among participating farmers was encouraged through the organization of group meetings before and after each production cycle.Shrimp culture, Aquaculture development, Brackishwater aquaculture, Mekong Delta, Viet Nam,

Gain and Frequency-Selectivity Enhancement of Dual-Polarized Filtering IBFD Antenna Using PRS

A dual-polarized filtering Fabry–Perot antenna (FPA) with high selectivity and high isolation is proposed for in-band full-duplex (IBFD) applications. The proposed antenna utilizes a square patch as the feeding element, which is fed by a double differential-fed scheme for dual-polarized radiation with high isolation. The patch is loaded with a symmetrical cross-slot and four shorting pins for a broad passband filtering feature. To enhance broadside gain across a wide frequency range, the patch is incorporated with a partially reflecting surface (PRS), which is composed of two complementary cross-slot and patch arrays. Moreover, the frequency selectivity of PRS is exploited to improve the filtering characteristic. The double differential feeds are realized based on out-of-phase power dividers, which are combined with simple low-pass filters to further improve the out-of-band suppression. The final design was fabricated and measured. The measurement results show excellent results with a 10-dB return loss bandwidth of 21.5% (4.91–6.09 GHz), isolation of greater than 40 dB, peak gain of 13.7 dBi, out-of-band suppression level of better than 27 dB, and a cross-polarization level of less than −27 dB

HIV-Associated TB in An Giang Province, Vietnam, 2001–2004: Epidemiology and TB Treatment Outcomes

BACKGROUND: Mortality is high in HIV-infected TB patients, but few studies from Southeast Asia have documented the benefits of interventions, such as co-trimoxazole (CTX), in reducing mortality during TB treatment. To help guide policy in Vietnam, we studied the epidemiology of HIV-associated TB in one province and examined factors associated with outcomes, including the impact of CTX use. METHODOLOGY/PRINCIPAL FINDINGS: We retrospectively abstracted data for all HIV-infected persons diagnosed with TB from 2001-2004 in An Giang, a province in southern Vietnam in which TB patients receive HIV counseling and testing. We used standard WHO definitions to classify TB treatment outcomes. We conducted multivariate analysis to identify risk factors for the composite outcome of death, default, or treatment failure during TB treatment. From 2001-2004, 637 HIV-infected TB patients were diagnosed in An Giang. Of these, 501 (79%) were male, 321 (50%) were aged 25-34 years, and the most common self-reported HIV risk factor was sex with a commercial sex worker in 221 (35%). TB was classified as smear-positive in 531 (83%). During TB treatment, 167 (26%) patients died, 9 (1%) defaulted, and 6 (1%) failed treatment. Of 454 patients who took CTX, 116 (26%) had an unsuccessful outcome compared with 33 (70%) of 47 patients who did not take CTX (relative risk, 0.4; 95% confidence interval [CI], 0.3-0.5). Adjusting for male sex, rural residence, TB smear status and disease location, and the occurrence of adverse events during TB treatment in multivariate analysis, the benefit of CTX persisted (adjusted odds ratio for unsuccessful outcome 0.1; CI, 0.1-0.3). CONCLUSIONS/SIGNIFICANCE: In An Giang, Vietnam, HIV-associated TB was associated with poor TB treatment outcomes. Outcomes were significantly better in those taking CTX. This finding suggests that Vietnam should consider applying WHO recommendations to prescribe CTX to all HIV-infected TB patients

Bandwidth enhancement utilizing bias Circuit as parasitic elements in a reconfigurable circularly polarized antenna

A circularly polarized (CP) crossed-dipole antenna with switchable rotating sense is presented. The proposed design has two main attractive features. First, a wide overlapped CP bandwidth (BW) is realized for both operating states. Second, unlike existing designs targeting a similar functionality, no biasing wire through ground plane is required, which significantly reduces the design complexity. The proposed design employs parasitic elements for two different roles. For RF signal, these parasitic elements open an additional CP resonance band to enhance the axial-ratio (AR) BW. Additionally, through RF chokes, they provide a de path to bias the p-i-n diodes. An antenna prototype was experimentally demonstrated with the capability of switching between two CP rotating senses in a frequency range from 1.1 to 2.02 GHz, equivalent to 58.9%. The antenna also exhibits a wide -10 dB impedance BW of 53.3% (1.1-1.9 GHz) with a peak gain of around 9.1 dBi and front-to-back ratio of more than 15 dB