So-called Physical Unclonable Functions are an emerging, new cryptographic and security primitive. They can potentially replace secret binary keys in vulnerable hardware systems and have other security advantages. In this paper, we deal with the cryptanalysis of this new primitive by use of machine learning methods. In particular, we investigate to what extent the security of circuit-based PUFs...

A theory of generalized gradients for a general class of functions is developed, as well as a corresponding theory of normals to arbitrary closed sets. It is shown how these concepts subsume the usual gradients and normals of smooth functions and manifolds, and the subdifferentials and normals of convex analysis. A theorem is proved concerning the differentiability properties of a function of t...

Color gradients in elliptical galaxies in distant clusters (z = 0.37 − 0.56) are examined by using the archival deep imaging data of Wide Field Planetary Camera 2 (WFPC2) on-board the Hubble Space Telescope (HST). Obtained color gradients are compared with the two model gradients to examine the origin of the color gradients. In one model, a color gradient is assumed to be caused by a metallicit...

We present a model-free reinforcement learning method for partially observable Markov decision problems. Our method estimates a likelihood gradient by sampling directly in parameter space, which leads to lower variance gradient estimates than obtained by regular policy gradient methods. We show that for several complex control tasks, including robust standing with a humanoid robot, this method ...

Chemical vapor deposition (CVD) co-polymerization was used to fabricate polymer coatings, which comprise of reactive surface composition gradients. Two functionalized derivatives of [2.2]paracyclophane were fed into a two-source CVD system at a 180 ° angle, then copolymerized and deposited as a polymer gradient. Infrared and X-ray photoelectron spectroscopy (XPS) confirmed the compositional cha...

We propose expected policy gradients (EPG), which unify stochastic policy gradients (SPG) and deterministic policy gradients (DPG) for reinforcement learning. Inspired by expected sarsa, EPG integrates across the action when estimating the gradient, instead of relying only on the action in the sampled trajectory. We establish a new general policy gradient theorem, of which the stochastic and de...

We describe a method to exploit the mass-transfer limitations of microcontact printing for the fabrication of surfaces with well-defined, arbitrarily shaped composition variations. An analysis of the transport processes reveals that the printing of hexadecanethiol (HDT) from poly(dimethylsiloxane) is purely diffusion-controlled. Stamps with geometries that enhance surface-normal diffusion paths...

OBSTRUCTION to left ventricular outflow has been considered a characteristic and functionally important feature of "hypertrophic subaortic stenosis." The presence of obstruction has been inferred from the finding of a pressure gradient within the left ventricle during catheterization of the left heart in certain patients with idiopathic left ventricular hypertrophy. Indeed, the disease was not ...

The longstanding problem of Brownian transport in a heterogeneous quasi one-dimensional medium with space-dependent self-diffusion coefficient is addressed in the overdamped (zero mass) limit. A satisfactory mesoscopic description is obtained in the Langevin equation formalism by introducing an appropriate drift term, which depends on the system macroscopic observables, namely the diffuser conc...

A useful question to ask of an image is whether it contains one or more instances of a certain object: a person, a face, a car, and so forth. Algorithms that answer this question are called object detectors. They often work by asking the same question in turn of every possible rectangle in the image that might possibly tightly bound one of the instances of interest. For instance, when detecting...