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Liveness detection technology has become an important application in daily life, and it is used in scenarios including mobile phone face unlock, face payment, and remote authentication. However, if attackers use fake video generation technology to generate realistic face-swapping videos to attack the living body detection system in the above scenarios, it will pose a huge threat to the security of these scenarios. Aiming at this problem, four state-of-the-art Deepfake technologies were used to generate a large number of face-changing pictures and videos as test samples, and use these samples to test the online API interfaces of commercial live detection platforms such as Baidu and Tencent. The test results show that the detection success rate of Deepfake images is generally very low by the major commercial live detection platforms currently used, and they are more sensitive to the quality of images, and the false detection rate of real images is also high. The main reason for the analysis may be that these platforms were mainly designed for traditional living detection attack methods such as printing photo attacks, screen remake attacks, and silicone mask attacks, and did not integrate advanced face-changing detection technology into their liveness detection. In the algorithm, these platforms cannot effectively deal with Deepfake attacks. Therefore, an integrated live detection method Integranet was proposed, which was obtained by integrating four detection algorithms for different image features. It could effectively detect traditional attack methods such as printed photos and screen remakes. It could also effectively detect against advanced Deepfake attacks. The detection effect of Integranet was verified on the test data set. The results show that the detection success rate of Deepfake images by proposed Integranet detection method is at least 35% higher than that of major commercial live detection platforms.

In this paper, we calculated the different forms of BaTiO3/BiCoO3 composite structure, predicting their visible light absorption performance based on the electronic structure using the first principles calculations. Firstly, six possible compounds that come from BaTiO3 and BiCoO3 were constructed. By calculating the different antiferromagnetic (AFM) structures of strip, columnar, and layered composite structures, it is found that the ground state of the composite structure changes to G‐type AFM structure from C‐type AFM structure of pure BiCoO3 under the influence of BaTiO3. Energy band calculations show that band gaps of three composite structures are smaller than those of pure BaTiO3 and pure BiCoO3. Furthermore, density of states analysis shows that the conduction band minimum (CBM) and valence band maximum (VBM) of three composite structures are mainly from the contribution of Co 3d and O 2p. For the characteristic that CBM and VBM of materials come from different atoms, it would reduce the recombination opportunities of electrons and holes and is conducive to the increase of photoelectric conversion efficiency under visible light irradiation. The calculation of optical properties shows that optical absorption coefficients of three composite structures are much larger than that of BaTiO3, especially the layered composite structure. There is a high absorption peak near 500 nm of the solar spectral irradiation maximum, which is significantly important to improve the optical energy conversion efficiency of the composite materials. The work provides an effective way for the application of wide band gap ferroelectric materials in ferroelectric photovoltaic. [ABSTRACT FROM AUTHOR]

In this paper, we calculated the different forms of BaTiO3/BiCoO3 composite structure, predicting their visible light absorption performance based on the electronic structure using the first principles calculations. Firstly, six possible compounds that come from BaTiO3 and BiCoO3 were constructed. By calculating the different antiferromagnetic (AFM) structures of strip, columnar, and layered composite structures, it is found that the ground state of the composite structure changes to G‐type AFM structure from C‐type AFM structure of pure BiCoO3 under the influence of BaTiO3. Energy band calculations show that band gaps of three composite structures are smaller than those of pure BaTiO3 and pure BiCoO3. Furthermore, density of states analysis shows that the conduction band minimum (CBM) and valence band maximum (VBM) of three composite structures are mainly from the contribution of Co 3d and O 2p. For the characteristic that CBM and VBM of materials come from different atoms, it would reduce the recombination opportunities of electrons and holes and is conducive to the increase of photoelectric conversion efficiency under visible light irradiation. The calculation of optical properties shows that optical absorption coefficients of three composite structures are much larger than that of BaTiO3, especially the layered composite structure. There is a high absorption peak near 500 nm of the solar spectral irradiation maximum, which is significantly important to improve the optical energy conversion efficiency of the composite materials. The work provides an effective way for the application of wide band gap ferroelectric materials in ferroelectric photovoltaic. [ABSTRACT FROM AUTHOR]