A review of signal processing algorithms employing Wi-Fi signals for positioning and recognition of human activities is presented. The principles of how channel state information (CSI) is used and how the Wi-Fi sensing systems operate are reviewed. It provides a brief introduction to the algorithms that perform signal processing, feature extraction and recognitions, including location, activity recognition, physiological signal detection and personal identification. Challenges and future trends of Wi-Fi sensing are also discussed in the end.

Currently, Infrastructure as a Service(IaaS) and Platform as a Service(PaaS) platforms play a role as a cloud operating system(COS).They are separated from each other in resource management, which may cause inconsistent resource status and result in the decrease of performance. Moreover, heterogeneous resources are not managed well in existing cloud computing platforms. Referring to the theory of operating system, we propose a unified architecture model of cloud operating system, which has six layers corresponding to the layered architecture of legacy operating system. Based on this architecture, a new cloud operating system called Hua-Cloud Computing System(HCOS) is realized. In HCOS, the hybrid resources are managed in a unified way. This method improves the unified scheduling capability of heterogeneous resources and eliminates the problem of resource status inconsistency. The main characteristics of HCOS are introduced and two typical applications are illustrated in this paper.

In the new era of railways, infrastructure, trains and travelers will be interconnected. In order to realize a seamless high-data rate wireless connectivity, up to dozens of GHz bandwidth is required. This motivates the exploration of the underutilized millimeter wave (mmWave) as well as the largely unexplored THz band. In this paper, we first identify relevant communication scenarios for railway applications. Then the specific challenges and estimates of the bandwidth requirements for high-data rate railway connectivity in these communication scenarios are described. Finally, we outline the major challenges on propagation channel modeling and provide a technical route for further studies.

As the information network plays a more and more important role globally, the traditional network theories and technologies , especially those related to network security, can no longer meet the network development requirements . Offering the system with secure and trusted services has become a new focus in network res earch . This paper first discusses the meaning of and aspects involved in the trusted network. According to this paper, the trusted network should be a network where the network s and users behaviors and their results are always predicted and manageable . The trustworthiness of a network mainly involves three aspects : service provider, information transmission and terminal user. This paper also analyzes the trusted network in terms of trusted model for network/user behaviors , architecture of trusted network, s ervice survivability and network manageability, which is designed to give ideas on solving the problems that may be faced in developing the trusted network.