54 research outputs found
Robust Detection of Moving Human Target Behind Wall via Impulse through-Wall Radar
Through-wall human target detection is highly desired in military applications. We have developed an impulse through-wall radar (TWR) to address this problem. In order to obtain a robust detection performance, firstly we adopt the exponential average background subtraction (EABS) method to mitigate clutters and improve the signal-to-clutter ratio (SCR). Then, different from the conventional constant false alarm rate (CFAR) methods that are applied along the fast-time dimension, we propose a new CFAR method along the slow-time dimension to resist the residual clutters in the clutter mitigation output because of timing jitters, based on the presence of a larger relative variation of human target moving in and out in comparison with that of residual clutters in the slow-time dimension. The proposed method effectively solves the false alarm issue caused by residual clutters in the conventional CFAR methods, and obtains robust detection performance. Finally, different through-wall experiments are provided to verify the proposed method.Defence Science Journal, 2013, 63(6), pp.636-642, DOI:http://dx.doi.org/10.14429/dsj.63.576
SD-MVS: Segmentation-Driven Deformation Multi-View Stereo with Spherical Refinement and EM optimization
In this paper, we introduce Segmentation-Driven Deformation Multi-View Stereo
(SD-MVS), a method that can effectively tackle challenges in 3D reconstruction
of textureless areas. We are the first to adopt the Segment Anything Model
(SAM) to distinguish semantic instances in scenes and further leverage these
constraints for pixelwise patch deformation on both matching cost and
propagation. Concurrently, we propose a unique refinement strategy that
combines spherical coordinates and gradient descent on normals and pixelwise
search interval on depths, significantly improving the completeness of
reconstructed 3D model. Furthermore, we adopt the Expectation-Maximization (EM)
algorithm to alternately optimize the aggregate matching cost and
hyperparameters, effectively mitigating the problem of parameters being
excessively dependent on empirical tuning. Evaluations on the ETH3D
high-resolution multi-view stereo benchmark and the Tanks and Temples dataset
demonstrate that our method can achieve state-of-the-art results with less time
consumption.Comment: 10 pages, 9 figures, published to AAAI202
Melatonin enhances the anti-tumor effect of fisetin by inhibiting COX-2/iNOS and NF-κB/p300 signaling pathways.
Melatonin is a hormone identified in plants and pineal glands of mammals and possesses diverse physiological functions. Fisetin is a bio-flavonoid widely found in plants and exerts antitumor activity in several types of human cancers. However, the combinational effect of melatonin and fisetin on antitumor activity, especially in melanoma treatment, remains unclear. Here, we tested the hypothesis that melatonin could enhance the antitumor activity of fisetin in melanoma cells and identified the underlying molecular mechanisms. The combinational treatment of melanoma cells with fisetin and melatonin significantly enhanced the inhibitions of cell viability, cell migration and clone formation, and the induction of apoptosis when compared with the treatment of fisetin alone. Moreover, such enhancement of antitumor effect by melatonin was found to be mediated through the modulation of the multiply signaling pathways in melanoma cells. The combinational treatment of fisetin with melatonin increased the cleavage of PARP proteins, triggered more release of cytochrome-c from the mitochondrial inter-membrane, enhanced the inhibition of COX-2 and iNOS expression, repressed the nuclear localization of p300 and NF-κB proteins, and abrogated the binding of NF-κB on COX-2 promoter. Thus, these results demonstrated that melatonin potentiated the anti-tumor effect of fisetin in melanoma cells by activating cytochrome-c-dependent apoptotic pathway and inhibiting COX-2/iNOS and NF-κB/p300 signaling pathways, and our study suggests the potential of such a combinational treatment of natural products in melanoma therapy
Deep Learning Application in Security and Privacy - Theory and Practice:A Position Paper
Technology is shaping our lives in a multitude of ways. This is fuelled by a
technology infrastructure, both legacy and state of the art, composed of a
heterogeneous group of hardware, software, services and organisations. Such
infrastructure faces a diverse range of challenges to its operations that
include security, privacy, resilience, and quality of services. Among these,
cybersecurity and privacy are taking the centre-stage, especially since the
General Data Protection Regulation (GDPR) came into effect. Traditional
security and privacy techniques are overstretched and adversarial actors have
evolved to design exploitation techniques that circumvent protection. With the
ever-increasing complexity of technology infrastructure, security and
privacy-preservation specialists have started to look for adaptable and
flexible protection methods that can evolve (potentially autonomously) as the
adversarial actor changes its techniques. For this, Artificial Intelligence
(AI), Machine Learning (ML) and Deep Learning (DL) were put forward as
saviours. In this paper, we look at the promises of AI, ML, and DL stated in
academic and industrial literature and evaluate how realistic they are. We also
put forward potential challenges a DL based security and privacy protection
technique has to overcome. Finally, we conclude the paper with a discussion on
what steps the DL and the security and privacy-preservation community have to
take to ensure that DL is not just going to be hype, but an opportunity to
build a secure, reliable, and trusted technology infrastructure on which we can
rely on for so much in our lives
Februus: Input Purification Defense Against Trojan Attacks on Deep Neural Network Systems
We propose Februus; a new idea to neutralize highly potent and insidious
Trojan attacks on Deep Neural Network (DNN) systems at run-time. In Trojan
attacks, an adversary activates a backdoor crafted in a deep neural network
model using a secret trigger, a Trojan, applied to any input to alter the
model's decision to a target prediction---a target determined by and only known
to the attacker. Februus sanitizes the incoming input by surgically removing
the potential trigger artifacts and restoring the input for the classification
task. Februus enables effective Trojan mitigation by sanitizing inputs with no
loss of performance for sanitized inputs, Trojaned or benign. Our extensive
evaluations on multiple infected models based on four popular datasets across
three contrasting vision applications and trigger types demonstrate the high
efficacy of Februus. We dramatically reduced attack success rates from 100% to
near 0% for all cases (achieving 0% on multiple cases) and evaluated the
generalizability of Februus to defend against complex adaptive attacks;
notably, we realized the first defense against the advanced partial Trojan
attack. To the best of our knowledge, Februus is the first backdoor defense
method for operation at run-time capable of sanitizing Trojaned inputs without
requiring anomaly detection methods, model retraining or costly labeled data.Comment: 16 pages, to appear in the 36th Annual Computer Security Applications
Conference (ACSAC 2020
Towards interpreting recurrent neural networks through probabilistic abstraction
National Research Foundation (NRF) Singapore under its AI Singapore Programm
Quantitative Identification of Water Sources of Coalbed Methane Wells, Based on the Hydrogen and Oxygen Isotopes of Produced Water—A Case of the Zhijin Block, South China
The quantitative identification of water sources is an important prerequisite for objectively evaluating the degree of aquifer interference and predicting the production potential of coalbed methane (CBM) wells. However, this issue has not been solved yet, and water sources are far from being completely understood. Stable water isotopes are important carriers of water source information, which can be used to identify the water sources for CBM wells. Taking the Zhijin block in the Western Guizhou Province as an example, the produced water samples were collected from CBM wells. The relationships between the stable isotopic compositions of the produced water samples and the production data were quantitatively analyzed. The following main conclusions were obtained. (1) The δD and δ18O values of the produced water samples were between −73.37‰ and −27.56‰ (average −56.30‰) and between −11.04‰ and −5.93‰ (average −9.23‰), respectively. The water samples have D-drift characteristics, showing the dual properties of atmospheric precipitation genesis and water–rock interaction modification of the produced water. An index d was constructed to enable the quantitative characterization of the degree of D-drift of the produced water. (2) The stable isotopic compositions of produced water showed the control of the water sources on the CBM productivity. The probability of being susceptible to aquifer interference increased with the increasing span of the producing seam combination, reflected in the lowering δD and δ18O values and the decreasing gas productivity. (3) Three types of water, namely, static water, dynamic water, and mixed water, were identified. The characteristic values of the isotopic compositions of the static and dynamic water were determined. Accordingly, a quantitative identification method for the produced water sources was constructed, based on their stable isotopic compositions. The identification results have a clear correlation with the gas production, and the output of the static water contributes to the efficient CBM production. The method for the quantitative identification of the water sources proposed in this study, can help to improve the CBM development efficiency and optimize the drainage technology
Quantitative Identification of Water Sources of Coalbed Methane Wells, Based on the Hydrogen and Oxygen Isotopes of Produced Water—A Case of the Zhijin Block, South China
The quantitative identification of water sources is an important prerequisite for objectively evaluating the degree of aquifer interference and predicting the production potential of coalbed methane (CBM) wells. However, this issue has not been solved yet, and water sources are far from being completely understood. Stable water isotopes are important carriers of water source information, which can be used to identify the water sources for CBM wells. Taking the Zhijin block in the Western Guizhou Province as an example, the produced water samples were collected from CBM wells. The relationships between the stable isotopic compositions of the produced water samples and the production data were quantitatively analyzed. The following main conclusions were obtained. (1) The δD and δ18O values of the produced water samples were between −73.37‰ and −27.56‰ (average −56.30‰) and between −11.04‰ and −5.93‰ (average −9.23‰), respectively. The water samples have D-drift characteristics, showing the dual properties of atmospheric precipitation genesis and water–rock interaction modification of the produced water. An index d was constructed to enable the quantitative characterization of the degree of D-drift of the produced water. (2) The stable isotopic compositions of produced water showed the control of the water sources on the CBM productivity. The probability of being susceptible to aquifer interference increased with the increasing span of the producing seam combination, reflected in the lowering δD and δ18O values and the decreasing gas productivity. (3) Three types of water, namely, static water, dynamic water, and mixed water, were identified. The characteristic values of the isotopic compositions of the static and dynamic water were determined. Accordingly, a quantitative identification method for the produced water sources was constructed, based on their stable isotopic compositions. The identification results have a clear correlation with the gas production, and the output of the static water contributes to the efficient CBM production. The method for the quantitative identification of the water sources proposed in this study, can help to improve the CBM development efficiency and optimize the drainage technology
SD-MVS: Segmentation-Driven Deformation Multi-View Stereo with Spherical Refinement and EM Optimization
In this paper, we introduce Segmentation-Driven Deformation Multi-View Stereo (SD-MVS), a method that can effectively tackle challenges in 3D reconstruction of textureless areas. We are the first to adopt the Segment Anything Model (SAM) to distinguish semantic instances in scenes and further leverage these constraints for pixelwise patch deformation on both matching cost and propagation. Concurrently, we propose a unique refinement strategy that combines spherical coordinates and gradient descent on normals and pixelwise search interval on depths, significantly improving the completeness of reconstructed 3D model. Furthermore, we adopt the Expectation-Maximization (EM) algorithm to alternately optimize the aggregate matching cost and hyperparameters, effectively mitigating the problem of parameters being excessively dependent on empirical tuning. Evaluations on the ETH3D high-resolution multi-view stereo benchmark and the Tanks and Temples dataset demonstrate that our method can achieve state-of-the-art results with less time consumption
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