Mobile edge computing (MEC) can enhance application performance effectively by offloading computation tasks to the edge server hosting corresponding service via multi-access wireless networks. However, existing service placement policies are more based on the assumption that application services can be used without restrictions, while ignoring the constraints of software usage by license, which always limits user number, usage periods, etc. To address these challenges, in this paper, we introduce an architecture of digital twin-empowered MEC with good scalability and reliability, formulate an optimal problem by jointly optimizing task offloading and service placement, which takes into account the usage number limitation for one service at the same time. To tackle this mix integer non-linear programming problem (MINLP), we propose a DRL-based algorithm JTOSP to deal with high-dimensional input data from MEC system, and to cope with the stochastic nature in dynamic underlying network efficiently. Numerical experiments are conducted and the simulation results show that our algorithm outperform other algorithms and reduce energy consumption efficiently.

Most of intrusion detection systems nowadays are not really distributed systems which cannot detect the distributed or cooperative attacks effectively. In this paper, an agent-based distributed cooperative model (ADCM) is proposed, which implements cooperative intrusion detection through efficient, normative event messages exchange among logic detection domains (LDD). Some specific detection agents are also presented which are independent separately, while they can communicate and cooperate with one another to take actions. The ADCM improves the ability of error tolerance and cooperation without degradation of efficiency. Prototype of a distributed intrusion detection system based on ADCM and the extended intrusion detection message exchange format is completed, which proves to be powerful as expected in detecting intrusions.