Adam and the Ants: On the Influence of the Optimization Algorithm on the Detectability of DNN Watermarks

As training Deep Neural Networks (DNNs) becomes more expensive, the interest in protecting the ownership of the models with watermarking techniques increases. Uchida et al. proposed a digital watermarking algorithm that embeds the secret message into the model coefficients. However, despite its appeal, in this paper, we show that its efficacy can be compromised by the optimization algorithm being used. In particular, we found through a theoretical analysis that, as opposed to Stochastic Gradient Descent (SGD), the update direction given by Adam optimization strongly depends on the sign of a combination of columns of the projection matrix used for watermarking. Consequently, as observed in the empirical results, this makes the coefficients move in unison giving rise to heavily spiked weight distributions that can be easily detected by adversaries. As a way to solve this problem, we propose a new method called Block-Orthonormal Projections (BOP) that allows one to combine watermarking with Adam optimization with a minor impact on the detectability of the watermark and an increased robustness.     

The heteroscorpionate ligand 2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1,1‐diphenylethanol and an easy preparation of its tungsten complex

The heteroscorpionate ligand 2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)‐1,1‐diphenylethanol, C₂₄H₂₆N₄O, features in the solid state an intramolecular O—H…N hydrogen bond. A heteroscorpionate tungsten complex, cis‐[2,2‐bis(3,5‐dimethylpyrazolyl)‐1,1‐diphenylethanolato]chloridodioxidotungsten(VI) tetrahydrofuran monosolvate, [W(C₂₄H₂₅N₄O)ClO₂]·C₄H₈O, was prepared by the simple mixing of solutions of the ligand and WOCl₄ in tetrahydrofuran. The tungsten complex was isolated after standing for several weeks. The complex exhibits a κ³N,N′,O‐coordination of the ligand. This simple synthetic procedure allows access to the cis isomer in high yield without additional purification steps. The Hirshfeld surface analysis shows a change of the intermolecular contacts due to the coordination of the WO₂Cl unit with the ligand molecule.     

Strongest postcondition semantics as the formal basis for reverse engineering

Reverse engineering of program code is the process of constructing a higher level abstraction of an implementation in order to facilitate the understanding of a system that may be in a “legacy” or “geriatric” state. Changing architectures and improvements in programming methods, including formal methods in software development and object-oriented programming, have prompted a need to reverse engineer and re-engineer program code. This paper describes the application of the strongest postcondition predicate transformer (sp) as the formal basis for the reverse engineering of imperative program code. This work is supported in part by the National Science Foundation grants CCR-9407318, CCR-9209873, and CDA-9312389. This author is supported in part by a NASA Graduate Student Researchers Program Fellowship.     

Physical Chemistry Online: Maximizing Your Potential

The Physical Chemistry On-Line (PCOL) consortium has developed and conducted a series of short-term projects for use in the physical chemistry curriculum. The projects involve faculty and students from geographically dispersed institutions, are short in duration (~4–6 weeks), and use email and the World Wide Web for communication and information distribution. They are designed to enhance physical chemistry at colleges and universities that may have limited resources available for physical chemistry by offering an alternate pedagogical approach. This paper will highlight the motivations of the participants, outline the specific projects used to date, and provide some evaluation of the pedagogical effectiveness of the approach.     

An improved crystal and molecular structure of guanidinium hydrogen oxalate monohydrate,C(NH 2)3HC2O4 · H2O

The title compound crystallizes in space groupP2₁/c witha = 6.6922 (25),b = 10.5468(8),c = 10.2125(19) Å, = 103.74(2) °, andZ = 4. The intensities were measured on an automated X-ray diffractometer, and the structure was refined to a finalR ₁ of 3.3% for 1106 reflections. The hydrogen bonding scheme is as reported by Adams (1978) with one additional bond found.