Binary Hypothesis Testing with Byzantine Sensors: Fundamental Trade-off Between Security and Efficiency

This paper studies binary hypothesis testing based on measurements from a set of sensors, a subset of which can be compromised by an attacker. The measurements from a compromised sensor can be manipulated arbitrarily by the adversary. The asymptotic exponential rate, with which the probability of error goes to zero, is adopted to indicate the detection performance of a detector. In practice, we expect the attack on sensors to be sporadic, and therefore the system may operate with all the sensors being benign for extended period of time. This motivates us to consider the trade-off between the detection performance of a detector, i.e., the probability of error, when the attacker is absent (defined as efficiency) and the worst-case detection performance when the attacker is present (defined as security). We first provide the fundamental limits of this trade-off, and then propose a detection strategy that achieves these limits. We then consider a special case, where there is no trade-off between security and efficiency. In other words, our detection strategy can achieve the maximal efficiency and the maximal security simultaneously. Two extensions of the secure hypothesis testing problem are also studied and fundamental limits and achievability results are provided: 1) a subset of sensors, namely "secure" sensors, are assumed to be equipped with better security countermeasures and hence are guaranteed to be benign, 2) detection performance with unknown number of compromised sensors. Numerical examples are given to illustrate the main results

Autonomous Ground Vehicle

WildCat is an autonomous ground vehicle (AGV). AGVs were first developed for military purposes: Intelligent Transportation Systems (ITS), Manufacturing, Search and Rescue operations, Mining, etc. WildCat will be entered in the Intelligent Ground Vehicle competition (IGVC) held in June 2016 at Oakland University in Rochester, Michigan. Teams from major universities not only in the U.S., but also India, France, the UK, China, and around the world will be competing. The IGVC offers a design experience that is at the very cutting edge of engineering education. It is multidisciplinary, theory-based, hands-on, team implemented, and outcome assessed competition. It encompasses the very latest technologies impacting industrial development and taps subjects of high interest to students. The objective of the competition is to challenge students to think creatively as a team about the evolving technologies of vehicle electronic controls, sensors, computer science, robotics, and system integration throughout the design, fabrication, and field testing of autonomous intelligent mobile robots. The vehicle will compete to: 1) autonomously navigate an outdoor obstacle course as quickly as possible, keeping within the speed limit and reaching all GPS waypoints, 2) complete a course with remote (user) control, and 3) have ingenuity and uniqueness in design

Kinetics and thermodynamics of electron transfer in Debye solvents: An analytical and nonperturbative reduced density matrix theory

A nonperturbative electron transfer rate theory is developed based on the reduced density matrix dynamics, which can be evaluated readily for the Debye solvent model without further approximation. Not only does it recover for reaction rates the celebrated Marcus' inversion and Kramers' turnover behaviors, the present theory also predicts for reaction thermodynamics, such as equilibrium Gibbs free-energy and entropy, some interesting solvent-dependent features that are calling for experimental verification. Moreover, a continued fraction Green's function formalism is also constructed, which can be used together with Dyson equation technique, for efficient evaluation of nonperturbative reduced density matrix dynamics.Comment: 8 pages, 5 figures. J. Phys. Chem. B, accepte

Time Circular Birefringence in Time-Dependent Magnetoelectric Media

Light traveling in time-dependent media has many extraordinary properties which can be utilized to convert frequency, achieve temporal cloaking, and simulate cosmological phenomena. In this paper, we focus on time-dependent axion-type magnetoelectric (ME) media, and prove that light in these media always has two degenerate modes with opposite circular polarizations corresponding to one wave vector $\mathbf{k}$, and name this effect "time circular birefringence" (TCB). By interchanging the status of space and time, the pair of TCB modes can appear simultaneously via "time refraction" and "time reflection" of a linear polarized incident wave at a time interface of ME media. The superposition of the two TCB modes causes the "time Faraday effect", namely the globally unified polarization axes rotate with time. A circularly polarized Gaussian pulse traversing a time interface is also studied. If the wave-vector spectrum of a pulse mainly concentrates in the non-traveling-wave band, the pulse will be trapped with nearly fixed center while its intensity will grow rapidly. In addition, we propose an experimental scheme of using molecular fluid with external time-varying electric and magnetic fields both parallel to the direction of light to realize these phenomena in practice.Comment: 17 pages, 6 figure