QEBA: Query-Efficient Boundary-Based Blackbox Attack

Machine learning (ML), especially deep neural networks (DNNs) have been widely used in various applications, including several safety-critical ones (e.g. autonomous driving). As a result, recent research about adversarial examples has raised great concerns. Such adversarial attacks can be achieved by adding a small magnitude of perturbation to the input to mislead model prediction. While several whitebox attacks have demonstrated their effectiveness, which assume that the attackers have full access to the machine learning models; blackbox attacks are more realistic in practice. In this paper, we propose a Query-Efficient Boundary-based blackbox Attack (QEBA) based only on model's final prediction labels. We theoretically show why previous boundary-based attack with gradient estimation on the whole gradient space is not efficient in terms of query numbers, and provide optimality analysis for our dimension reduction-based gradient estimation. On the other hand, we conducted extensive experiments on ImageNet and CelebA datasets to evaluate QEBA. We show that compared with the state-of-the-art blackbox attacks, QEBA is able to use a smaller number of queries to achieve a lower magnitude of perturbation with 100% attack success rate. We also show case studies of attacks on real-world APIs including MEGVII Face++ and Microsoft Azure.Comment: Accepted by CVPR 202

Microscopic Particle Manipulation via Optoelectronic Devices

The optoelectronic tweezers (or optically induced dielectrophoresis (DEP)) have showed the ability to parallelly position a large number of colloidal microparticles without any template. The microparticles can be trapped and driven by the dielectrophoretic forces induced by the optical micropatterns in OET devices. In this chapter, the design and fabrication of flat optoelectronic devices (FOD) and hybrid optoelectronic device (HOD) are described. In the typical FOD, the manipulation modes including filtering, transporting, concentrating and focusing controlling regimes are experimentally demonstrated and analyzed. The controllable rotation of self-assembled microparticle chains in FOD has also been investigated, and a method incorporating the optically induced electrorotation (OER) and AC electroosmotic (ACEO) effects is numerically and experimentally implemented for manipulating microparticle chains. Based on the above research of FOD, a hybrid DEP microdevice HOD is conceptually and experimentally proposed. The HOD integrates with metallic microelectrode layer and the underneath photoconductive layer with projected optical virtual electrodes. FOD and HOD hybrid device enables the active driving, large-scale patterning and local position adjustment of microparticles. These techniques make up the shortcoming of low flexibility of traditional metallic microelectrodes and integrate the merits of both the metal electrode-induced and microimage-induced DEP techniques

Regulation of cell death by transfer RNA.

SIGNIFICANCE: Both transfer RNA (tRNA) and cytochrome c are essential molecules for the survival of cells. tRNA decodes mRNA codons into amino-acid-building blocks in protein in all organisms, whereas cytochrome c functions in the electron transport chain that powers ATP synthesis in mitochondrion-containing eukaryotes. Additionally, in vertebrates, cytochrome c that is released from mitochondria is a potent inducer of apoptosis, activating apoptotic proteins (caspases) in the cytoplasm to dismantle cells. A better understanding of both tRNA and cytochrome c is essential for an insight into the regulation of cell life and death. RECENT ADVANCES: A recent study showed that the mitochondrion-released cytochrome c can be removed from the cell-death pathway by tRNA molecules. The direct binding of cytochrome c by tRNA provides a mechanism for tRNA to regulate cell death, beyond its role in gene expression. CRITICAL ISSUES: The nature of the tRNA-cytochrome c binding interaction remains unknown. The questions of how this interaction affects tRNA function, cellular metabolism, and apoptotic sensitivity are unanswered. FUTURE DIRECTIONS: Investigations into the critical issues raised above will improve the understanding of tRNA in the fundamental processes of cell death and metabolism. Such knowledge will inform therapies in cell death-related diseases

How do auditors perceive and respond to client firms’ technological peer pressure? Evidence from going-concern opinions

We examine how the technological aspect of competition (or technological peer pressure) affects the likelihood that auditors issue going-concern opinions. We find that a client firm’s technological peer pressure increases the likelihood that the firm receives a going-concern opinion. This finding is consistent with the notion that the perceived auditor business risk increases with client technological peer pressure so that auditors are more likely to issue going-concern opinions to such clients. Further evidence shows that this positive effect is more pronounced for client firms with greater innovation originality, that are financially constrained, and for auditors facing higher litigation risk. We also find that technological peer pressure reduces the probability of both Type I and Type II misclassifications when auditors exert more effort. Additional analyses show that client firms’ technological peer pressure positively affects the likelihood of using auditors specialized in auditing R&D. Taken together, our study implies that auditors exert more effort to increase audit quality in response to the higher auditor business risk induced by clients’ technological peer pressure, instead of simply being conservative

Resveratrol protects the retina from I/R injury by inhibiting RGCS apoptosis, glial activation and expression of inflammatory factors

Purpose: To study the protective effect of resveratrol against retinal injury induced by ischemiareperfusion (I/R), and the underlying mechanism  action.Methods: Retinal I/R injury was established in 72 healthy male SD rats. The rats were assigned to 3 groups: control, model and resveratrol groups, with 24 rats in each group. Pathological changes in retina were determined using H&E staining. Retinal ganglion cells (RGCs) were counted usingfluorescence gold retrograde staining. Western blotting was used to assay the expressions of caspase- 3, Bax, Bcl-2, GFAP, COX-2 and iNOS. The expressions of COX-2 and iNOS were measured by immunofluorescence.Results: The retina in the control group was dense and ordered, and its morphology was normal. In contrast, the retina in the model group was thinner, with loose cells and disordered structure. In the resveratrol group, the retina was thicker, the structure was orderly, and the cells were dense. Relative to control, the population of RGCs in model rat retina was significantly reduced, and the expressions of Bcl-2, Bax, caspase-3, GFAP, COX-2 and iNOS were significantly upregulated (p < 0.05). In the resveratrol group, the number of RGCs in the retina was markedly elevated, relative to model rats, and the expressions of Bcl-2, Bax, caspase-3, GFAP, COX-2 and iNOS were significantly decreased (p < 0.05).Conclusion: Resveratrol protects the retina from I/R injury in rats by inhibiting RGCs apoptosis, glial activation and expressions of inflammatory factors. Thus, this compound may be potentially suitable for the management of retina damage. Keywords: Resveratrol, RGCs apoptosis, Glial activation, Inflammatory factors, I/R injur

Molecular Basis and Consequences of the Cytochrome c-tRNA Interaction.

The intrinsic apoptosis pathway occurs through the release of mitochondrial cytochrome c to the cytosol, where it promotes activation of the caspase family of proteases. The observation that tRNA binds to cytochrome c revealed a previously unexpected mode of apoptotic regulation. However, the molecular characteristics of this interaction, and its impact on each interaction partner, are not well understood. Using a novel fluorescence assay, we show here that cytochrome c binds to tRNA with an affinity comparable with other tRNA-protein binding interactions and with a molecular ratio of ∼3:1. Cytochrome c recognizes the tertiary structural features of tRNA, particularly in the core region. This binding is independent of the charging state of tRNA but is regulated by the redox state of cytochrome c. Compared with reduced cytochrome c, oxidized cytochrome c binds to tRNA with a weaker affinity, which correlates with its stronger pro-apoptotic activity. tRNA binding both facilitates cytochrome c reduction and inhibits the peroxidase activity of cytochrome c, which is involved in its release from mitochondria. Together, these findings provide new insights into the cytochrome c-tRNA interaction and apoptotic regulation

FOCUSING ON CENTRALITY MEASURE IN EMERGENCY MEDICAL SERVICES

Emergency Medical Services (EMS) attracted many researchers because the demand of EMS was increasing over time. One of the major concerns of EMS is the response time and ambulance despatching is one of the vital factors which affects the response time. This paper focuses on the problem of ambulance despatching when many emergency calls emerge in a short time, which exists under the condition of catastrophic natural or manmade disasters. We modify a new method for ambulance despatching by centrality measure, this method constructs a nearest-neighbor coupled emergency call network and then prioritize those calls by the score of fitness, where the score of fitness considers two factors: centralized measure a call by the emergency call network and the closest policy which means despatching to the closest call site. This method is testified by a series of simulation experiments on the real topology road network of Hong Kong Island which contains 8 hospitals. These analyses demonstrate the real situation and proof the potential of centrality measure in reducing response time of EMS

Comparison between transgenic maize with exotic betaine aldehyde dehydrogenase (BADH) gene and its untransformed counterpart

We investigated the performance of a transgenic maize (Zea mays L) line with an exotic betaine aldehyde dehydrogenase (BADH) gene and its untransformed counterpart under drought and normal water conditions. Membrane permeability, osmoprotectant contents, and antioxidant enzyme activities of the maize lines as well as plant height and biomass were compared. The results showed that, under drought stress, compared with the untransgenic line, the contents of glycine betaine (GB), soluble sugars, soluble proteins and proline of the trans- genic line were significantly higher, so was the peroxidase (POD) activity; the contents of superoxide anion free radical, malondialdehyde (MDA) and the electrical conductivity of the transgenic line were lower; plant height and the biomass of the transgenic line were significantly higher. Under normal water conditions, the contents of soluble protein and MDA content of the transgenic line were significantly lower; but it was not the case for the content of superoxide anion free radical, electrical conductivity and superoxide dismutase (SOD) activity. No significant difference was observed in GB content and, the plant height and the biomass between the 2 lines. We conclude that the transgenic maize with exotic BADH gene was superior over its untransformed counterpart under drought stress and they performed similarly under normal water conditions