PDF files are adopted for launching cyberattacks because of their popularity and the increasing number of relative vulnerabilities. Machine learning algorithms are developed to detect the maliciousness of PDF files. A...
PDF files are adopted for launching cyberattacks because of their popularity and the increasing number of relative vulnerabilities. Machine learning algorithms are developed to detect the maliciousness of PDF files. As the exploits of new vulnerabilities occur, the assumption that the training data and the test data share the same distribution does not hold and the ability of origin model to detect exploits of new vulnerabilities weakens gradually. In a real environment, it is very difficult to obtain numerous samples of exploits with the same CVE. and the machine learning models are difficult to be improved by retraining. Virtual sample generation could be used to generate sufficient virtual samples by small sample sets to improve the generalization of the existing model. A new VSG algorithm based on prior knowledge is proposed in this paper, which performs better than other VSG algorithms in improving the detection on exploits of new vulnerabilities.
The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interactio...
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The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of −2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of −2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.
Aiming at the problem of insufficient defense ability of fingerprint detection, the anti-reconnaissance model of host fingerprint based on virtual node is proposed. The model constructs periodically reconfigurable vir...
Aiming at the problem of insufficient defense ability of fingerprint detection, the anti-reconnaissance model of host fingerprint based on virtual node is proposed. The model constructs periodically reconfigurable virtual nodes, dynamically camouflages the fingerprint information of the host to deceive the detector, and redirect attack traffic targeting virtual nodes to honeypots that can capture and analyze attack behavior. Honeypot, as an active defense technology, can effectively improve the model's defense capabilities. This paper introduces probabilistic models for the defense model to provide a deeper understanding of the theoretical effect their parameters have for cybersecurity, which quantifies the impact of different parameters on the probability of attack success, such as the number of probes, number of honeypot mapping rules, the virtual node deception rate, the honeypot detection rate and allowable losses. Furthermore, our prototype system using Software Defined Network (SDN) and Data Plane Development Kit (DPDK) verifies the effectiveness of the model against reconnaissance.
The atmospheric quality plays an important role in the air shower observation by the Wide Field-of-view Cherenkov Telescope Array (WFCTA) of LHAASO. A YAG imaging lidar system was developed to continuously monitor the...
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In order to satisfy the requirement of service presenters’ credibility for recommendation system, this paper puts forward a method based on the analysis of the presenters’ reputation record to find the credible pres...
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Matrix completion is widely used in machine learning, engineering control, image processing, and recommendation systems. Currently, a popular algorithm for matrix completion is Singular Value Threshold (SVT). In this ...
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The accurate and reliable description of measurement devices is a central problem in both observing uniquely nonclassical behaviors and realizing quantum technologies from powerful computing to precision metrology. To...
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The accurate and reliable description of measurement devices is a central problem in both observing uniquely nonclassical behaviors and realizing quantum technologies from powerful computing to precision metrology. To date quantum tomography is the prevalent tool to characterize quantum detectors. However, such a characterization relies on accurately characterized probe states, rendering reliability of the characterization lost in circular argument. Here we report a self-characterization method of quantum measurements based on reconstructing the response range—the entirety of attainable measurement outcomes, eliminating the reliance on known states. We characterize two representative measurements implemented with photonic setups and obtain fidelities above 99.99% with the conventional tomographic reconstructions. This initiates range-based techniques in characterizing quantum systems and foreshadows novel device-independent protocols of quantum information applications.
Galactic diffuse gamma ray emission (GDE) is introduced by the galactic cosmic rays interacting with the interstellar medium (ISM) and/or radiation fields (ISRF). Studying galactic diffuse TeV γ-ray emission would he...
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Cosmic rays are high-energy charged particles that come from outer space. They play an important role in the evolution of our Galaxy. Gamma-ray emission produced by cosmic rays is a direct probe of cosmic rays and the...
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The Wide Field-of-view Cherenkov Telescope Array (WFCTA) of Large High Altitude Air Shower Observatory (LHAASO) is designed to measure the Cherenkov and fluorescent light created in the extensive air showers by cosmic...
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