| 1. |
- He, Xingkang, et al.
(författare)
-
Secured Filters Based on Saturated Innovations
- 2022
-
Ingår i: Security and Resilience of Control Systems. - Cham : Springer Nature. ; , s. 3-29
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In this chapter, we study how to design secure centralized and distributed filters for linear time-invariant systems with bounded noise under false data injection attacks in sensor networks. An adversary is able to compromise a subset of sensors and manipulate the measurements arbitrarily. We provide two motivating examples for this problem setup from smart buildings and autonomous vehicles. Then we design a centralized filter based on a saturation method, which gives a small gain if the innovation is large enough, indicating the high likelihood of compromised measurements. The estimation error of the secure centralized filter is proved to be asymptotically upper-bounded. Moreover, a secure two-time-scale distributed filter is obtained by modifying the centralized filter and employing an estimate consensus approach. Boundedness of the estimation error of the distributed filter is proved. Numerical simulations are provided in the end to show the usefulness of the two filters.
|
|
| 2. |
- Hu, X., et al.
(författare)
-
Left-handed transmission line of low pass and its applications
- 2010
-
Ingår i: Metamaterials. - Boston, MA : Springer. - 9781441905727 ; , s. 357-364
-
Bokkapitel (refereegranskat)abstract
- We introduce a novel left-handed (LH) transmission line (TL), which is based on a structure of identical symmetrical lattice type. While all the LH-TLs reported previously are of high pass, the present LH-TL has a wide left-handed low-pass band. Compared with a conventional right-handed transmission line, this LH-TL has a phase shift difference of 180° independent of the frequency. We also analyze the effect of a non-ideal component in a practical case, i.e., when the inductance of the shorted line in the lattice section cannot be neglected. The dispersion relations between the practical case and the ideal case are given and compared. It is shown that the introduction of the inductance of the shorted line will not change the left-handedness and low-pass property of the LH-TL, but make the phase response vary slightly. In the application example of broadband 180° hybrid ring, the constant-phase-shift property of the proposed LH-TL is utilized. The broadband hybrid ring is shown to have a very high isolation and about 42% bandwidth ratio.
|
|
