This paper discusses problems about video security based on H.264 video compression encoding standard, puts forward a design scheme of encryption about video meeting. The video encryption system combines with AES (Advanced Encryption Standard) algorithm, H.264 and the chaos encryption. In this scheme, AES is used in encrypting DCT Coefficients and motion vector symbol sequence of H.264. The protection of video movement information and video texture information is achieved in this video encryption system. Chaos encryption technology is used to generate the video conference keys to ensure the unpredictability of the key. Experiments show that the system can achieve rapid video encryption computing and smooth video conferencing. It also can protect video data against wiretapping and attack, it improve the confidentiality of the communication, Group members can be safe and effective authentication services can be achieved.
The implement of two algorithm,Data Encryption Standard(DES) and Advanced Encryption Standard(AES) were discussed.Compared with DES,AES has more superiority in efficiency and security.
[Objective] The purpose was to discuss the acute toxicity effect of racemate of Peng-3 and its enantiomer on Daphina magna.[Method] The standard experiment animals Daphina magna was used to study the acute toxicity effect of O,O-dimethyl-1-(phenoxyacetoxy) ethylphosphonate on Daphina magna.[Result]The results showed that 48 h-LC50 of Rac-Peng3,Peng-3 pk1and Peng-3 pk2 for Daphnia magna were 0.274 1,0.368 5 and 0.262 3 mg/L,respectively.They were all high toxicity,but the difference of toxicity among them was not distinct.[Conclusion]This study will provide the scientific reference for the research on harm of aquatic organisms.
By analyzing positive effects brought by role exchange of teacher and students in the process of exploring study in higher vocational teaching,the essay seeks to find new methods in training creative men of caliber.
With the rapid popularization of the Internet age and development of the Internet in people's lives more and more important,we can say he has become a people without a good helper,but accompanied by the Internet security has become increasingly prominent.How to protect user data safety and security of the entire system has become the focus and core.This paper to the author's knowledge-based network,focuses on the defense to build a network security system of the research process.
Video-conference encryption based on H.264 was discussed.A scheme of encryption combined with Advanced Encryption Standard(AES),H.264 and the chaos encryption was put forward.The problem of user authentication,key generation,key distribution and video data security was solved and the experiment was carried out.
An dual-spectrum detection system is proposed on the requirement of UV detection,it can be used for ultraviolet and visi-ble image collection,registration and fusion based on DM642 as a core. The result indicates that this method is really effective in the UV signal detection and orientation.
Two failure mode,beam failure mode and column failure mode,of RC frame with specially-shaped column at elevated temperature,are studied at the basis of test.The structure characteristic of the deformation and inner force of the two types of failure mode are presented.Beam failure mode has the feature of ductility deformation,while column failure mode has brittle feature,which should be avoided in structure design.
This paper designs and implements a security video monitor system with H.264 encryption support. This System is based on DSP TMS320C6711 and ARM920T. This paper also puts forward a encryption scheme combining with AES (Advanced Encryption Standard) algorithm and H.264. It solves the problems of video data security and presents the experimental result of improved encryption algorithm.
Spectrometer adjustment is an important component of physics experiment in universities, which effectively improves experimental skills of students. Spectrometer is a sophisticated optical measuring instrument and some certain steps are needed in its adjustment. It takes a long time in the two steps: adjustment of the telescope to infinite distance, and adjustment of the light axes of telescope to be perpendicular to principal spinning axes. The difficulties and principles in the two steps are analyzed in this paper and an efficient adjustment method is suggested, which adjusts the telescope light axes and principal spinning axes at right angle through slant plane mirror. This method proves effective in practice.
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