129 research outputs found
On the Effectiveness of Adversarial Samples against Ensemble Learning-based Windows PE Malware Detectors
Recently, there has been a growing focus and interest in applying machine
learning (ML) to the field of cybersecurity, particularly in malware detection
and prevention. Several research works on malware analysis have been proposed,
offering promising results for both academic and practical applications. In
these works, the use of Generative Adversarial Networks (GANs) or Reinforcement
Learning (RL) can aid malware creators in crafting metamorphic malware that
evades antivirus software. In this study, we propose a mutation system to
counteract ensemble learning-based detectors by combining GANs and an RL model,
overcoming the limitations of the MalGAN model. Our proposed FeaGAN model is
built based on MalGAN by incorporating an RL model called the Deep Q-network
anti-malware Engines Attacking Framework (DQEAF). The RL model addresses three
key challenges in performing adversarial attacks on Windows Portable Executable
malware, including format preservation, executability preservation, and
maliciousness preservation. In the FeaGAN model, ensemble learning is utilized
to enhance the malware detector's evasion ability, with the generated
adversarial patterns. The experimental results demonstrate that 100\% of the
selected mutant samples preserve the format of executable files, while certain
successes in both executability preservation and maliciousness preservation are
achieved, reaching a stable success rate
Experiment and FEM Modelling of Bond Behaviors between Pre-stressing Strands and UltraâHighâPerformance Concrete
The objective of this paper is to investigate the bond properties of prestressing strands embedded in UltraâHighâPerformance Concrete (UHPC).The UHPC was made in laboratory using local materials in Vietnam.Its mixture contains: silica aggregates, portland cement PC40, fly ash, silica fume, polycarboxylate superplasticizer and the micro steel fibers.The experimental process is realized on a pull-out test. The volume fraction of micro steel fibers in UHPC was 2%. The prestressing strand with diameters of 15.2mm was considered. The interface shear strength between strand and UHPC is identified based on the results of force and displacement obtained during the pull-out test. The Cohesive Zone Model (CZM) is implemented in finite element model to study this interface behavior. This model described by a piecewise linear elastic law. The CZMâs parameters are identified based on experimental results of pull-out test.The numerical studies are used the CZM in ANSYS software. Two numerical tests are realized and compared with experimental results: pull-out test and other test to verify the deflection of I girder due to prestressing force
Depth-dose distribution in potatoes with low-energy X-rays
Irradiation is known as a handful measure to inhibit potato sprouting, kill harmful bacteria, and increase preservation. The absorbed dose is one of the essential characteristics of the irradiation process. In this study, the depth-dose distributions in potatoes and polymethyl methacrylate were investigated under low-energy X-ray irradiation by using the Fricke dosimeter and Gafchromic film dosimeter. The dose rates required for the rays to penetrate in polymethyl methacrylate were compared with those in potatoes. Polymethyl methacrylate could be used as a phantom in measuring the depth dose delivered in potatoes. The difference in depth-dose distribution in potatoes between one-sided and double-sided irradiation was also investigated. The calculated dose uniformity ratio values are 5.8 and 1.9 for potatoes irradiating one-sided and double-sided
Generating and Reversing Chronic Wounds in Diabetic Mice by Manipulating Wound Redox Parameters
By 2025, more than 500âM people worldwide will suffer from diabetes; 125âM will develop foot ulcer(s) and 20âM will undergo an amputation, creating a major health problem. Understanding how these wounds become chronic will provide insights to reverse chronicity. We hypothesized that oxidative stress (OS) in wounds is a critical component for generation of chronicity. We used the db/db mouse model of impaired healing and inhibited, at time of injury, two major antioxidant enzymes, catalase and glutathione peroxidase, creating high OS in the wounds. This was necessary and sufficient to trigger wounds to become chronic. The wounds initially contained a polymicrobial community that with time selected for specific biofilm-forming bacteria. To reverse chronicity we treated the wounds with the antioxidants α-tocopherol and N-acetylcysteine and found that OS was highly reduced, biofilms had increased sensitivity to antibiotics, and granulation tissue was formed with proper collagen deposition and remodeling. We show for the first time generation of chronic wounds in which biofilm develops spontaneously, illustrating importance of early and continued redox imbalance coupled with the presence of biofilm in development of wound chronicity. This model will help decipher additional mechanisms and potentially better diagnosis of chronicity and treatment of human chronic wounds
Pollen and seed morphology of cleome species (Cleomaceae) in Vietnam
Cleomaceae is a family that includes 18 genera distributed worldwide in tropical and temperate regions. Cleome L. is the largest genus having 207 species, widely distributed in tropical and subtropical regions (POWO 2019). In Vietnam, the genus is represented by four species Cleome rutidosperma DC., C. houtteana Schltdl., C. viscosa L. and C. gynandra L. The present study documents the pollen and seed characteristics of all four species of Cleome in Vietnam, and the data obtained using light microscope and scanning electron microscope are analyzed considering their importance in taxonomic delimitation and understanding their phylogenetic relationship. The results indicated a close relationship between different pollen and aperture types. The striking differences between the pollen shapes among different species of Cleome could be useful in taxonomic and evolutionary studies. Similarly, seed shape and surface characters provided important clues for their delimitation. Based on the pollen and seed morphological characteristics, a taxonomic key has been provided for easy identification of the Cleome species in Vietnam
The Role of Bacterial Biofilms in Chronic Infections
Biofilm is the virulence factor that is responsible for chronic infection in diseases such as Cystic Fibrosis (CF) and chronic wounds. In this thesis, we examine the role of AlgX, a required protein for alginate biosynthesis in P. aeruginosa. We show that the absence of AlgX resulted in the loss of mucoidy and in silico studies demonstrated that AlgX binds alginate. Alanine mutations demonstrated that K396, T398, W400, and R406 are important for alginate binding. Alginate rescue assays confirm the importance of these amino acid residues for alginate biosynthesis and acetylation. This is the first functional demonstration of AlgX role in alginate biofilm biosynthesis and acetylation.Biofilm-producing bacteria and redox imbalance are the leading factors that turn acute wounds into chronic wounds. We demonstrated that LIGHT-/- mouse wounds contain elevated levels of reactive oxygen species (ROS). To see whether chronic wounds can be generated, we increased the redox imbalance in the LIGHT-/- wounds and infecting the wounds with biofilm-forming bacteria. We demonstrated that by using these conditions, we could induce chronic wounds in the LIGHT-/- mouse model 100% of the time. These wounds do not re-epithelialize, contain high bacterial burden, and sustained multi-species bacterial infections that are biofilm-forming and antibiotic-resistant.We also demonstrated that increasing the redox imbalance was sufficient to turn db/db wounds into chronic wounds. These wounds sustained spontaneous biofilm- producing bacterial infections. To verify that redox imbalance is critical for chronicity, we treated chronic wounds with antioxidants and found that oxidative stress was highly reduced, biofilm production was decreased, and bacteria became more sensitive to antibiotics. This is the first demonstration that chronic wounds can be generated and reversed by manipulating the wound's redox microenvironment in an animal model.Norspermidine has been shown to negatively affect the structure of extracellular polymeric substances (EPS). Using the bacteria that colonized db/db chronic wounds, we demonstrated that 2 mM norspermidine reduces the amount of adherent biofilms produced by exudate bacterial communities. Furthermore, application of norspermidine increases the bactericidal effect of gentamicin. We believe that norspermidine could be used in combination with bactericidal antibiotics to control biofilm infection in dermal chronic wounds
The Vietnamese Polyfunctional Marker MĂ as a Generalized Linker: A Multilevel Approach
The main aim of this paper is to illustrate the notions of polyfunctionality and transcategoriality as described in Robert (2003, 2004) through the case study of the marker mĂ in modern Vietnamese. We lay out a multilevel analysis to account for its flexible categorial status. It will be proposed that mĂ is best treated as a Generalized Linker whose basic function consists in connecting two constituents of different types. We show that the transcategorial behavior of this morpheme results from its ability to operate on different levels: phrase level (relativizer, verbal conjunction), clause level (correlative conjunction), and sentence level (attitudinal sentence-final particle, discourse connector). In our account, the uses of mĂ at the sentence level and the weakening of its core function are the byproduct of some form of ellipsis targeting one of the two constituents connected by mĂ
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