An evolutionary approach to the identification of Cellular Automata based on partial observations

In this paper we consider the identification problem of Cellular Automata (CAs). The problem is defined and solved in the context of partial observations with time gaps of unknown length, i.e. pre-recorded, partial configurations of the system at certain, unknown time steps. A solution method based on a modified variant of a Genetic Algorithm (GA) is proposed and illustrated with brief experimental results.Comment: IEEE CEC 201

A split-and-perturb decomposition of number-conserving cellular automata

This paper concerns $d$-dimensional cellular automata with the von Neumann neighborhood that conserve the sum of the states of all their cells. These automata, called number-conserving or density-conserving cellular automata, are of particular interest to mathematicians, computer scientists and physicists, as they can serve as models of physical phenomena obeying some conservation law. We propose a new approach to study such cellular automata that works in any dimension $d$ and for any set of states $Q$. Essentially, the local rule of a cellular automaton is decomposed into two parts: a split function and a perturbation. This decomposition is unique and, moreover, the set of all possible split functions has a very simple structure, while the set of all perturbations forms a linear space and is therefore very easy to describe in terms of its basis. We show how this approach allows to find all number-conserving cellular automata in many cases of $d$ and $Q$. In particular, we find all three-dimensional number-conserving CAs with three states, which until now was beyond the capabilities of computers

Number-conserving cellular automata with a von Neumann neighborhood of range one

We present necessary and sufficient conditions for a cellular automaton with a von Neumann neighborhood of range one to be number-conserving. The conditions are formulated for any dimension and for any set of states containing zero. The use of the geometric structure of the von Neumann neighborhood allows for computationally tractable conditions even in higher dimensions.Comment: 15 pages, 3 figure

New higher-derivative invariants in N=2 supergravity and the Gauss-Bonnet term

A new class of N=2 locally supersymmetric higher-derivative invariants is constructed based on logarithms of conformal primary chiral superfields. They characteristically involve a coupling to R_{\mu\nu}^2 - 1/3*R^2, which equals the non-conformal part of the Gauss-Bonnet term. Upon combining one such invariant with the known supersymmetric version of the square of the Weyl tensor, one obtains the supersymmetric extension of the Gauss-Bonnet term. The construction is carried out in the context of both conformal superspace and the superconformal multiplet calculus. The new class of supersymmetric invariants resolves two open questions. The first concerns the proper identification of the 4D supersymmetric invariants that arise from dimensional reduction of the 5D mixed gauge-gravitational Chern-Simons term. The second is why the pure Gauss-Bonnet term without supersymmetric completion has reproduced the correct result in calculations of the BPS black hole entropy in certain models.Comment: 45 pages; v2: version to appear in JHE

Electric quadrupole and magnetic dipole moments of odd nuclei near the magic ones in a self-consistent approach

We present a model which describes the properties of odd-even nuclei with one nucleon more, or less, with respect to the magic number. In addition to the effects related to the unpaired nucleon, we consider those produced by the excitation of the closed shell core. By using a single particle basis generated with Hartree-Fock calculations, we describe the polarization of the doubly magic-core with Random Phase Approximation collective wave functions. In every step of the calculation, and for all the nuclei considered, we use the same finite-range nucleon-nucleon interaction. We apply our model to the evaluation of electric quadrupole and magnetic dipole moments of odd-even nuclei around oxygen, calcium, zirconium, tin and lead isotopes. Our Random Phase Approximation description of the polarization of the core improves the agreement with experimental data with respect to the predictions of the independent particle model. We compare our results with those obtained in first-order perturbation theory, with those produced by Hartree-Fock-Bogolioubov calculations and with those generated within the Landau-Migdal theory of finite Fermi systems. The results of our universal, self-consistent, and parameter free approach have the same quality of those obtained with phenomenological approaches where the various terms of the nucleon-nucleon interaction are adapted to reproduce some specific experimental data. A critical discussion on the validity of the model is presented.Comment: 18 pages, 7 figures, 7 table

A dynamical systems approach to the discrimination of the modes of operation of cryptographic systems

Evidence of signatures associated with cryptographic modes of operation is established. Motivated by some analogies between cryptographic and dynamical systems, in particular with chaos theory, we propose an algorithm based on Lyapunov exponents of discrete dynamical systems to estimate the divergence among ciphertexts as the encryption algorithm is applied iteratively. The results allow to distinguish among six modes of operation, namely ECB, CBC, OFB, CFB, CTR and PCBC using DES, IDEA, TEA and XTEA block ciphers of 64 bits, as well as AES, RC6, Twofish, Seed, Serpent and Camellia block ciphers of 128 bits. Furthermore, the proposed methodology enables a classification of modes of operation of cryptographic systems according to their strength.Comment: 14 pages, 10 figure

Attrition-enhanced total resolution leads to homochiral families of amino acid derivatives

The total resolution of five structurally similar racemizable amino acid derivatives, three of which have racemic crystal structures, was performed simultaneously. By enantioselective incorporation in an amino acid derivative that forms a conglomerate the other four were deracemized on attrition-induced grinding. The outcome of the resolution was random (R) or (S), but all compounds had the same absolute configuration and high enantiomeric purities.

Effect of induction of subacute ruminal acidosis on milk fat profile and rumen parameters

High-concentrate diets can lead to subacute ruminal acidosis and are known to result in changes of the ruminal fermentation pattern and mammary secretion of fatty acids. The objective of this paper is to describe modifications in milk fatty acid proportions, particularly odd- and branched-chain fatty acids and rumen biohydrogenation intermediates, associated with rumen parameters during a 6-wk subacute ruminal acidosis induction protocol with 12 ruminally fistulated multiparous cows. The protocol involved a weekly gradual replacement of a standard dairy concentrate with a wheat-based concentrate (610 g of wheat/kg of concentrate) during the first 5 wk and an increase in the total amount of concentrate in wk 6. Before the end of induction wk 6, cows were switched to a control diet because 7 cows showed signs of sickness. The pH was measured continuously by an indwelling pH probe. Milk and rumen samples were taken on d 2 and 7 of each week. Data were analyzed using a linear mixed model and by principal component analysis. A pH decrease occurred after the first concentrate switch but rumen parameters returned to the original values and remained stable until wk 5. In wk 5 and 6, rumen pH values were indicative of increasing acidotic conditions. After switching to the control diet in wk 6; rumen pH values rapidly achieved normal values. Odd- and branched-chain fatty acids and C18:1 trans-10 increased with increasing amount of concentrate in the diet, whereas C18:1 trans-11 decreased. Four fatty acids [C18:1 trans-10, C15:0 and C17:0+C17:1 cis-9 (negative loadings), and iso C14:0 (positive loading)] largely correlated with the first principal component (PC1); with cows spread along the PC1 axis. The first 4 wk of the induction experiment showed variation across the second principal component (PC2) only, with high loadings of anteiso C13:0 (negative loading) and C18:2 cis-9,trans-11 and C18:1 trans-11 (positive loadings). Weeks 5 and 6 deviated from PC2 and tended toward the negative PC1 axis. A discriminant analysis using a stepwise approach indicated the main fatty acids discriminating between the control and acidotic samples as iso C13:0, iso C16:0, and C18:2 cis-9. trans-11 rather than milk fat content. or C18:1 trans-10; which have been used before as indicators of acidosis. This shows that specific milk fatty acids have potential in discriminating acidotic cases

A Parametric Analysis of Prospect Theory's Functionals for the General Population

This paper presents the results of an experiment that completely measures the utility function and probability weighting function for different positive and negative monetary outcomes, using a representative sample of N = 1935 from the general public. The results confirm earlier findings in the lab, suggesting that utility is less pronounced than what is found in classical measurements where expected utility is assumed. Utility for losses is found to be convex, consistent with diminishing sensitivity, and the obtained loss aversion coefficient of 1.6 is moderate but in agreement with contemporary evidence. The estimated probability weighing functions have an inverse-S shape and they imply pessimism in both domains. These results show that probability weighting is also an important phenomenon in the general population. Women and lower educated individuals are found to be more risk averse, in agreement with common findings. Unlike previous studies that ascribed gender differences in risk attitudes solely to differences in the degree utility curvature, however, our results show that this finding is primarily driven by loss aversion and, for women, also by a more pessimistic psychological response towards the probability of obtaining the best possible outcome.loss aversion, utility for gains and losses, prospect theory, subjective probability weighting