Limited Query Black-box Adversarial Attacks in the Real World
We study the creation of physical adversarial examples, which are robust to real-world transformations, using a limited number of queries to the target black-box neural networks. We observe that robust models tend to be especially susceptible to foreground manipulations, which motivates our novel Foreground attack. We demonstrate that gradient priors are a useful signal for black-box attacks and therefore introduce an improved version of the popular SimBA. We also propose an algorithm for transferable attacks that selects the most similar surrogates to the target model. Our black-box attacks outperform state-of-the-art approaches they are based on and support our belief that the concept of model similarity could be leveraged to build strong attacks in a limited-information setting.
Anti-bacterial Crab bio-bandages with Bio-dressings 2.0
Commercially available bandages such as hydrocolloid are neither biodegradable nor anti-bacterial. Chitin is known to be the second most naturally available polysaccharide which could be transformed to chitosan which is known to be anti-bacterial (Hasan, 2018) (Chao, 2019) and haemostatic (Okamoto, 2003) (Hu, 2018). Chitosan can be further converted to hydrogel which is bio-degradable and has good water absorbance. Anti-bacterial crab bio-bandages and crab bio-dressings should be bio-degradable as it took 42 days and a month for complete bio-degradation respectively, so they should be better than commercial bandages such as Nexcare Hydrocolloid as the disposal of anti-bacterial crab bio-bandages with bio-dressings would no longer pose burden to landfilling or threat to our environment. Anti-bacterial crab bio-bandages with bio-dressings are anti-bacterial with degree of deacetylation of DD% (measured using FTIR Spectrum II) 82.6% (due to the presence of chitosan) even without the application of other anti-bacterial agents and hence can provide complete protection of wounds from skin and soft tissues infections and haemostatic (due to the presence of chitosan). After testing and certification based on IS997:2004 and BS EN 13726-1, they should meet many requirements specified. Anti-bacterial crab bio-bandages should be eligible for marketing. Some results were as follows: 1.4 Anti-bacterial effect of crab hydrogels and roasted crab hydrogels Pure chitosan, crab chitosan, crab hydrogels and roasted crab hydrogels showed significant anti-bacterial effect. NO oral bacterial colonies were present in drinking water with crab hydrogels. Thus crab hydrogels could serve as effective anti-bacterial wound dressings. 1.6 Basing on IS997:2004 standard, the load per unit of area of anti-bacterial bio-bandages was 342g/m2 which met the minimum requirement of 36g/m2, the anti-bacterial bio-bandages had stronger tension strength (>20N both in dry and wet conditions) than commercial hydrocolloid. (2.7N dry 2.8N wet) which was comparable with that required (50-67N) and pH of about 7 which met the pH range of 4.5-8. 1.7 The FSA Free-Swell Absorbency of synthetic blood of crab hydrogel bio-dressings was 1.86g per 5cm x 5cm dressing which was much higher than that of commercial hydrocolloid (0.299g per 5cm x 5cm dressing) based on BS EN 13726-1.
What is the relationship between angular velocity and power efficiency of a twin blanded single rotor helicopter system, in hover?
A traditional helicopter requires 60 - 80% more power to hover than when in forward or lateral flight, making the manoeuvre extremely power inefficient. To maximise efficiency, industrially many properties of the helicopter and rotor have been changed and tested, for example: optimising blade shape, fuselage shape and changing weights of different helicopter components. This report in particular aims to find a relationship between power efficiency and angular velocity for a twin bladed hovering helicopter with a single rotor. The angular velocity of a blade measures the frequency of its revolution about a fixed point. A theoretical approach was first taken and then justified with empirical data. Firstly, a model for power efficiency was derived with William Froude’s momentum and blade element theory. The efficiency equations incorporated the thrust and power coefficients. Therefore, the research focused on determining values for these coefficients by manipulating equations, using industrial specifications and simulations from the XFOIL software. In order to validate the accuracy for such theoretically generated data, an experiment was conducted for a comparison. The theoretical and empirical data were concurrent, as they followed a similar trend and the empirical values overlapped within the theoretical error bars. The power efficiency for different angular velocities were then found by substituting values for the coefficients. The results demonstrated a positive relationship; where, as angular velocity increases, power efficiency increases too, then plateaus and repeats the same trend once again. The research raises many questions and could be extended by determining if a similar relationship exists for tri-copters and quadcopters.
HOST TARGET PROTEINS OF SPIKE PROTEIN OF SARS-COV-2
Coronavirus Disease 2019 (COVID-19) is a newly emerged infectious disease caused by the new severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV-2). In less than one year, the virus has spread around the entire world, killing millions of people and disrupting travel and business worldwide. During infection, the virus uses its Spike protein to dock onto the Ace2 protein on the surface of its human host cell. Spike is 1273 amino acids long and only a short fragment of Spike (319-541) is sufficient to bind Ace2. We hypothesized that the remaining protein sequences of Spike might have functions for viral replication beyond the binding of Ace2. We have performed Split-Ubiquitin protein-protein interaction screens to isolate human proteins by their ability to bind to Spike, and we have identified Annexin2A2 and Cytochrome b as novel human protein interaction partners of Spike. Annexin2A2 is involved in both endocytosis and exocytosis, and the protein interaction with Spike might help the virus to enter and exit its host cell. The presence of the mitochondrial Cytochrome b protein inside the cytosol promotes apoptosis, and the protein interaction with Spike could speed up sapoptosis of the infected human cell. The Nub cDNA libraries that we have generated also allowed us to screen for synthetic peptides that interact with Spike. We have isolated two synthetic peptides, FL1a and FL7a, derived from the non-coding parts of human mRNAs by their ability to interact with Spike. We found that both FL1a and FL7a interact with the C-terminal half of the Spike protein. We also found that FL7a is able to block the Spike-Spike self-interaction at the C-terminal half of the Spike protein and we think that this could block the reassembly of the Spike protein in the host cell during viral reassembly. We hope that those synthetic peptides could be used as drugs due to their ability to block protein-protein interactions of Spike with human host proteins that are essential for viral replication.
PVA unveiled the actual role of starch in the Briggs-Rauscher reaction
The Briggs Rauscher reaction (BR reaction) is one of the famous oscillating reactions; the aqueous mixture of KIO3, H2SO4, H2O2, C3H4O4, MnSO4, and starch exhibit color change between yellow and blue-purple repeatedly. The blue-purple color formation is due to the iodine test reaction caused by inclusions of polyiodides such as I3- and I5- in the helical structure of starch. Therefore, starch has been regarded as only an indicator in the BR reaction. But our seniors have found that the oscillation did not last without starch. They hypothesized that starch’s linear helical framework is necessary to elongate the lifetime of the oscillating reaction. If this hypothesis is correct, similar BR-type oscillations must be observed when other polymers with helical structures are used instead of starch. We found the literature which reports that polyvinyl alcohol (PVA) forms a helical structure and indicates the iodine test reaction. In our research, we studied the BR reactions using PVA, with different saponification degrees and viscosities. First, we studied the correlation between the structural features of PVA and the iodine color reaction by spectroscopic approach, exhibiting that PVA with low saponification form helical structures and show the iodine color reactions, which gives red color solutions. Second, we found that additions of the helical-structured PVA to the reaction solution instead of starch induces the BR-type oscillating reactions, while PVA without helical structure induces only a few numbers of oscillations. This is the world-first example of the oscillating reaction using PVA. The oscillation that lasted for 6 minutes with 23 oscillations was almost the same as that of the general BR reaction using starch. We concluded that the polymers with helical structures are intrinsic to elongate the lifetime of the BR reaction. Furthermore, we found that the addition of K3[Fe(CN)6], which has a high redox activity, in the reaction solution with PVA drastically elongated the lifetime (50 min) and increased the numbers of the oscillations (nearly 100 times). This result suggests that the oxidation-reduction reactions by the ferricyanide ion promotes the redox process of iodine and iodide ions.
Limited Query Black-box Adversarial Attacks in the Real World
We study the creation of physical adversarial examples, which are robust to real-world transformations, using a limited number of queries to the target black-box neural networks. We observe that robust models tend to be especially susceptible to foreground manipulations, which motivates our novel Foreground attack. We demonstrate that gradient priors are a useful signal for black-box attacks and therefore introduce an improved version of the popular SimBA. We also propose an algorithm for transferable attacks that selects the most similar surrogates to the target model. Our black-box attacks outperform state-of-the-art approaches they are based on and support our belief that the concept of model similarity could be leveraged to build strong attacks in a limited-information setting.