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"Melman, Anna"
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Image data hiding schemes based on metaheuristic optimization: a review
The digital content exchange on the Internet is associated with information security risks. Hiding data in digital images is a promising direction in data protection and is an alternative to cryptographic methods. Steganography algorithms create covert communication channels and protect the confidentiality of messages embedded in cover images. Watermarking algorithms embed invisible marks in images for further image authentication and proof of the authorship. The main difficulty in the development of data hiding schemes is to achieve a balance between indicators of embedding quality, including imperceptibility, capacity, and robustness. An effective approach to solving this problem is the use of metaheuristic optimization algorithms, such as genetic algorithm, particle swarm optimization, artificial bee colony, and others. In this paper, we present an overview of data hiding techniques based on metaheuristic optimization. We review and analyze image steganography and image watermarking schemes over the past 6 years. We propose three levels of research classification: embedding purpose level, optimization purpose level, and level of metaheuristics. The results demonstrate the high relevance of using metaheuristic optimization in the development of new data hiding algorithms. Based on the results of the review, we formulate the main problems of this scientific field and suggest promising areas for further research.
Journal Article
An Authorship Protection Technology for Electronic Documents Based on Image Watermarking
In the field of information technology, information security technologies hold a special place. They ensure the security of the use of information technology. One of the urgent tasks is the protection of electronic documents during their transfer in information systems, including smart systems. This paper proposes a technology for protecting electronic documents containing digital images. The main idea is that the electronic document authorship can be protected by embedding digital watermarks in the images that are contained in this document. The paper considers three cases of using the proposed technology: full copying of an electronic document, copying of images contained in the document, and copying of text. It is shown that in all three cases, the authorship confirmation can be successfully implemented. Some areas of the proposed technology application are described, including augmented reality applications. Computational experiments are conducted with robust watermarking algorithms that can be used within the technology. A scenario of technology implementation is proposed which provides for the joint use of different class algorithms.
Journal Article
An adaptive algorithm for embedding information into compressed JPEG images using the QIM method
The widespread use of JPEG images makes them good covers for secret messages storing and transmitting. This paper proposes a new algorithm for embedding information in JPEG images based on the steganographic QIM method. The main problem of such embedding is the vulnerability to statistical steganalysis. To solve this problem, it is proposed to use a variable quantization step, which is adaptively selected for each block of the JPEG cover image. Experimental results show that the proposed approach successfully increases the security of embedding.
Paper
An authorship protection technology for electronic documents based on image watermarking
In the field of information technology, information security technologies hold a special place. They ensure the security of the use of information technology. One of the urgent tasks is the protection of electronic documents during their transfer in information systems. This paper proposes a technology for protecting electronic documents containing digital images. The main idea is that the electronic document authorship protection can be implemented by digital watermark embedding in the images that are contained in this document. The paper considers three cases of using the proposed technology: full copying of an electronic document, copying of images contained in the document, and copying of text. It is shown that in all three cases the authorship confirmation can be successfully implemented. Computational experiments are conducted with robust watermarking algorithms that can be used within the technology. A scenario of technology implementation is proposed, which provides for the joint use of different class algorithms.
Paper
On performance of PBFT for IoT-applications with constrained devices
Cyber-physical systems and the Internet of things (IoT) is becoming an integral part of the digital society. The use of IoT services improves human life in many ways. Protection against cyber threats is an important aspect of the functioning of IoT devices. Malicious activities lead to confidential data leakages and incorrect performance of devices are becoming critical. Therefore, development of effective solutions that can protect both IoT devices data and data exchange networks turns in to a real challenge. This study provides a critical analysis of the feasibility of using blockchain technology to protect constrained IoT devices data, justifies the choice of Practical Byzantine Fault Tolerance (PBFT) consensus algorithm for implementation on such devices, and simulates the main distributed ledger scenarios using PBFT. The simulation results demonstrate the efficiency of the blockchain technology for constrained devices and make it possible to evaluate the applicability limits of the chosen consensus algorithm.
Paper
Randomized Trial of Tenofovir With or Without Peginterferon Alfa Followed by Protocolized Treatment Withdrawal in Adults With Chronic Hepatitis B
Hepatitis B surface antigen (HBsAg) loss is associated with improved long-term outcomes of patients with chronic hepatitis B but is infrequently achieved with current monotherapies. We assessed whether combination strategies that included treatment withdrawal enhanced HBsAg loss.
A randomized (1:1) trial of tenofovir disoproxil fumarate (TDF) for 192 weeks with or without peginterferon (PegIFN) alfa-2a for the first 24 weeks, followed by withdrawal of TDF at week 192 with 48 weeks of off-treatment follow-up to week 240. The primary end point was HBsAg loss at week 240.
Of 201 participants (52% HBeAg positive, 12%/6% genotype A/A2, 7% cirrhosis) randomized to TDF + PegIFN (n = 102) or TDF alone (n = 99), 6 participants had lost HBsAg at the end of the treatment phase (week 192), 5 (5.3%) in the combination group, and 1 (1.0%) in the TDF alone group ( P = 0.09). By week 240, 9 participants had cleared HBsAg, 5.3% in combination, and 4.1% in monotherapy arms ( P = 0.73). HBsAg decline and loss occurred earlier with TDF + PegIFN than TDF, with a ≥1-logIU/mL qHBsAg decline by week 24 in 28% in TDF + PegIFN compared with 6% in TDF ( P = 0.04). HBsAg loss occurred in 7 of 12 (58%) with hepatitis B virus subgenotype A2 (all HBeAg positive) compared with only 2 of 189 (1%) with other hepatitis B virus genotypes and in 8 of 93 (8.6%) HBeAg positive vs 1 of 87 (1.1%) HBeAg negative.
PegIFN combined TDF followed by protocolized TDF withdrawal led to earlier but not higher percentages of HBsAg clearance. Pretreatment HBeAg positivity and subgenotype A2 were strongly associated with HBsAg clearance.
Journal Article
Hepatic Steatosis and Steatohepatitis in a Large North American Cohort of Adults With Chronic Hepatitis B
Fatty liver disease (FLD) influences liver disease progression and liver cancer risk. We investigated the impact of FLD on liver disease severity in a large North American cohort with chronic hepatitis B virus (HBV).
Liver biopsies from 420 hepatitis B surface antigen-positive adults enrolled in the Hepatitis B Research Network and who were not on HBV therapy in the previous month were evaluated for inflammation and fibrosis. Steatohepatitis was based on steatosis, hepatocyte ballooning ± Mallory-Denk bodies, and perisinusoidal fibrosis. Models evaluated factors associated with steatohepatitis, and the associations of steatohepatitis with fibrosis, and longitudinal alanine aminotransferase, aspartate aminotransferase, and Fibrosis-4.
The median age was 42 years, 62.5% were male, and 79.5% were Asian. One hundred thirty-two (31.4%) patients had FLD (77 [18.3%] steatosis only, 55 [13.1%] steatohepatitis). Older age, overweight/obesity, and diabetes were associated with steatohepatitis. Steatohepatitis (vs no FLD) was associated with 1.68 times higher risk of advanced fibrosis at baseline (95% confidence interval, 1.12-2.51), and there was an indication of higher incident cirrhosis rate during follow-up. Steatohepatitis vs no FLD was also independently associated with, on average, 1.39 times higher alanine aminotransferase (P < 0.01) and 1.25 times higher Fibrosis-4 (P = 0.04) across 4 years.
Coexisting steatosis occurred in nearly a third of adults (13% had steatohepatitis) with chronic HBV in this North American cohort who underwent liver biopsies. Steatohepatitis was associated with advanced fibrosis and higher biochemical measures of hepatic inflammation over time. Therefore, in addition to viral suppression, screening for and managing metabolic abnormalities is important to prevent disease progression in HBV.
Journal Article
Effects of Perfluorinated Alkyl Substances (PFAS) on Amphibian Body and Liver Conditions: Is Lipid Metabolism Being Perturbed throughout Metamorphosis?
Per- and polyfluoroalkyl substances (PFAS) may interact with peroxisome proliferator activated receptors (PPARs) and alter lipid homeostasis. Using Xenopus laevis, we investigated the effect of PFAS on (a) lipid homeostasis and whether this correlated to changes in body and hepatic condition; (b) the expression of hepatic genes regulated by PPAR; and (c) the hepatic lipidome. We chronically exposed tadpoles to 0.5 µg/L of either PFOS, PFHxS, PFOA, PFHxA, a binary mixture of PFOS and PFHxS (0.5 µg/L of each), or a control, from NF stage 52 through metamorphic climax. Growth, development, and survival were not affected, but we detected a sex-specific decrease in body condition at NF 66 (6.8%) and in hepatic condition (16.6%) across metamorphic climax for male tadpoles exposed to PFOS. We observed weak evidence for the transient downregulation of apolipoprotein-V (apoa5) at NF 62 in tadpoles exposed to PFHxA. Acyl-CoA oxidase 1 (acox1) was downregulated only in males exposed to PFHxS (Ln(Fold Change) = −0.54). We detected PFAS-specific downregulation of structural glycerophospholipids, while semi-quantitative profiling detected the upregulation in numerous glycerophospholipids, sphingomyelins, and diglycerides. Overall, our findings indicate that PFAS can induce sex-specific effects that change across larval development and metamorphosis. We demonstrate that PFAS alter lipid metabolism at environmentally relevant concentrations through divergent mechanisms that may not be related to PPARs, with an absence of effects on body condition, demonstrating the need for more molecular studies to elucidate mechanisms of PFAS-induced lipid dysregulation in amphibians and in other taxa.
Journal Article
Patient Knowledge, Beliefs and Barriers to Hepatitis B Care: Results of a Multicenter, Multiethnic Patient Survey
BackgroundA greater understanding of the determinants of health behavior among those with and at-risk of chronic hepatitis B virus (HBV) infection is needed for effective design and implementation of public health initiatives.AimsTo determine factors associated with (1) willingness to accept HBV antiviral treatment and (2) satisfaction with provider communication regarding HBV care in a diverse cohort of HBV-infected patients.MethodsUsing a multifaceted model of health behavior, the Health Behavior Framework, we conducted a comprehensive assessment of knowledge, attitudes, beliefs, and barriers to HBV care.ResultsWe enrolled 510 patients, with mean age 46 years; 53.1% men; and 71.6% Asian or Hawaiian/Pacific Islander. Patients were knowledgeable about HBV infection, but one-fifth did not think that HBV was a treatable disease; over a quarter felt it was so common among family and friends that it did not concern them, and less than half of patients believed they were likely to have liver problems or transmit HBV to others during their lifetime. Perceived susceptibility to disease risk was the only independent predictor of willingness to accept HBV treatment (β = 0.23, p = 0.0005), and contrary to expectations, having a doctor that speaks the same language was predictive of lower patient satisfaction with provider communication about their HBV care (β = − 0.65, p < 0.0001).ConclusionsPatients with greater perceived susceptibility to the health consequences of HBV infection are more likely to accept treatment, and patient–provider language concordance impacts patient satisfaction with communication regarding HBV care in an unexpected direction.
Journal Article