The Fundamental Importance of Adversarial Examples to Machine Learning

Many new products nowadays were made possible by advances in machine learning, in particular image recognition and automatic speech recognition. Examples are spam filters, virtual personal assistants, traffic prediction in GPS devices, or face recognition. Real-world machine learning applications see more widespread use and enjoy ever increasing accuracy on common benchmark datasets.  Unfortunately, it has been observed that virtually all models return incorrect results if data is fed to the model that is not from common benchmark datasets, data that was purposefully but imperceptibly altered, and plain garbage data. In this blog post I will talk about the purposeful, imperceptible input modifications, so-called adversarial examples. I will present possible kinds of modifications in computer vision and requirements for successful attacks before discussing attempts to improve models. Finally, I will make two predictions about the future of machine learning models. The appendix contains remarks about the misinterpretation of the largest eigenvalue of a weight matrix; the modulus of this value is almost meaningless without considering the smallest eigenvalues, too.

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Faster RANLUX Pseudo-Random Number Generators

RANLUX denotes a class of high-quality pseudo-random number generators (PRNGs) with long periods, solid theoretical foundations, and uses in computational physics. These generators are built on top of add-with-carry and subtract-with-borrow PRNGs which allow customization through three user-provided parameters yet there are only two variants in use today working internally with 24-bit and 48-bit arithmetic; this comes at a cost because modern computers do not possess instructions for 24-bit or 48-bit arithmetic. In this blog post I will present the theory behind RANLUX PRNGs, a list of possible parameters for 16-, 32-, and 64-bit RANLUX generators, criteria for selecting generators as well as benchmarks comparing the most competitive RANLUX variants with the RANLUX generators in the C++11 standard library, the Mersenne Twister, and xoshiro128+.

Some of the new RANLUX flavors are easily implemented in C++11 (sometimes in only two lines of code), they are  faster than the existing RANLUX flavors, they retain all desirable properties of a RANLUX generator, and they pass all DieHarder and TestU01 BigCrush PRNG tests.

The programs used to compute the RANLUX parameters are called ranlux-tools. They are free software under the terms of the Mozilla Public License 2.0 and can be found online:

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