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In this paper, the global dynamics of a periodic SEIR epidemic model is investigated. The basic reproductive number R0 is defined. It is proved that the disease-free equilibrium is globally stable if R0 < 1. The disease-free equilibrium is unstable and the disease remains endemic when R0 > 1. The existence of the periodic solution is investigated, and it is proved that the periodic model...
Although electronic documents have been greatly improved in the transferring speed and processing speed, it would also result that electronic documents information is disclosed, counterfeited, tampered, repudiated and so on. In order to solve the above problems and greatly improve the security of electronic documents, this paper researches a hybrid encryption technology, that is, encryption technology,...
Rural Information is an objective requirement of building new socialist countryside, a necessary prerequisite for the farmers' income increasing, agricultural efficiency, and rural development. Whether “Last mile” problem could well resolve is directly related to success or failure of information technology in rural areas. Resolving rural information “last mile” problem can help to narrow the urban-rural...
The electronic of government documents transmission and processing has greatly improved working efficiency. However, because the network has openness, connectivity and other features, resulting the network vulnerable to be attacked by hacker and viruses, and also resulting in information of electronic documents disclosure, counterfeiting, tampering, repudiation and many other issues. This paper firstly...
With the development of e-government, there is a serious lack of compound talents who both understand information technology and the government management, how to meet the market demands, how to lay a solid foundation for their future work is become a serious problem. In order to solve these problems, this paper first puts forward the necessity and urgency of teaching reform, then present the market...
Polarization space-borne sensor, just like POLDER (Polarization and Directionality of the Earth's Reflectances), is a new instrument devoted to the global observation of solar radiation reflected by the Earth surface-atmosphere system. It is necessary to acquire polarized information in retrieval of aerosol properties over land surface. Often the aerosol contribution is small compared to the surface,...
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