2,840 research outputs found
Quantum Key Distribution
This chapter describes the application of lasers, specifically diode lasers,
in the area of quantum key distribution (QKD). First, we motivate the
distribution of cryptographic keys based on quantum physical properties of
light, give a brief introduction to QKD assuming the reader has no or very
little knowledge about cryptography, and briefly present the state-of-the-art
of QKD. In the second half of the chapter we describe, as an example of a
real-world QKD system, the system deployed between the University of Calgary
and SAIT Polytechnic. We conclude the chapter with a brief discussion of
quantum networks and future steps.Comment: 20 pages, 12 figure
Statistical Watermarking for Networked Control Systems
Watermarking can detect sensor attacks in control systems by injecting a
private signal into the control, whereby attacks are identified by checking the
statistics of the sensor measurements and private signal. However, past
approaches assume full state measurements or a centralized controller, which is
not found in networked LTI systems with subcontrollers. Since generally the
entire system is neither controllable nor observable by a single subcontroller,
communication of sensor measurements is required to ensure closed-loop
stability. The possibility of attacking the communication channel has not been
explicitly considered by previous watermarking schemes, and requires a new
design. In this paper, we derive a statistical watermarking test that can
detect both sensor and communication attacks. A unique (compared to the
non-networked case) aspect of the implementing this test is the state-feedback
controller must be designed so that the closed-loop system is controllable by
each sub-controller, and we provide two approaches to design such a controller
using Heymann's lemma and a multi-input generalization of Heymann's lemma. The
usefulness of our approach is demonstrated with a simulation of detecting
attacks in a platoon of autonomous vehicles. Our test allows each vehicle to
independently detect attacks on both the communication channel between vehicles
and on the sensor measurements
First experiences with Personal Networks as an enabling platform for service providers
By developing demonstrators and performing small-scale user trials, we found various opportunities and pitfalls for deploying personal networks (PNs) on a commercial basis. The demonstrators were created using as many as possible legacy devices and proven technologies. They deal with applications in the health sector, home services, tourism, and the transportation sector. This paper describes the various architectures and our experiences with the end users and the technology. We conclude that context awareness, service discovery, and content management are very important in PNs and that a personal network provider role is necessary to realize these functions under the assumptions we made. The PNPay Travel demonstrator suggests that PN service platforms provide an opportunity to develop true trans-sector services
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