SIMPAL: A Compositional Reasoning Framework for Imperative Programs

The Static IMPerative AnaLyzer (SIMPAL) is a tool for performing compositional reasoning over software programs that utilize preexisting software components. SIMPAL features a specification language, called Limp, for modeling programs that utilize preexisting components. Limp is an extension of the Lustre synchronous data flow language. Limp extends Lustre by introducing control flow elements, global variables, and syntax specifying preconditions, postconditions, and global variable interactions of preexisting components. SIMPAL translates Limp programs to an equivalent Lustre representation which can be passed to the JKind model checking tool to perform assume-guarantee reasoning, reachability, and viability analyses. The feedback from these analyses can be used to refine the program to ensure the software functions as intended

ADGS-2100 Adaptive Display and Guidance System Window Manager Analysis

Recent advances in modeling languages have made it feasible to formally specify and analyze the behavior of large system components. Synchronous data flow languages, such as Lustre, SCR, and RSML-e are particularly well suited to this task, and commercial versions of these tools such as SCADE and Simulink are growing in popularity among designers of safety critical systems, largely due to their ability to automatically generate code from the models. At the same time, advances in formal analysis tools have made it practical to formally verify important properties of these models to ensure that design defects are identified and corrected early in the lifecycle. This report describes how these tools have been applied to the ADGS-2100 Adaptive Display and Guidance Window Manager being developed by Rockwell Collins Inc. This work demonstrates how formal methods can be easily and cost-efficiently used to remove defects early in the design cycle

Approximate and exact nodes of fermionic wavefunctions: coordinate transformations and topologies

A study of fermion nodes for spin-polarized states of a few-electron ions and molecules with $s,p,d$ one-particle orbitals is presented. We find exact nodes for some cases of two electron atomic and molecular states and also the first exact node for the three-electron atomic system in $^4S(p^3)$ state using appropriate coordinate maps and wavefunction symmetries. We analyze the cases of nodes for larger number of electrons in the Hartree-Fock approximation and for some cases we find transformations for projecting the high-dimensional node manifolds into 3D space. The node topologies and other properties are studied using these projections. We also propose a general coordinate transformation as an extension of Feynman-Cohen backflow coordinates to both simplify the nodal description and as a new variational freedom for quantum Monte Carlo trial wavefunctions.Comment: 7 pages, 7 figure

The Complexity of Computing Minimal Unidirectional Covering Sets

Given a binary dominance relation on a set of alternatives, a common thread in the social sciences is to identify subsets of alternatives that satisfy certain notions of stability. Examples can be found in areas as diverse as voting theory, game theory, and argumentation theory. Brandt and Fischer [BF08] proved that it is NP-hard to decide whether an alternative is contained in some inclusion-minimal upward or downward covering set. For both problems, we raise this lower bound to the Theta_{2}^{p} level of the polynomial hierarchy and provide a Sigma_{2}^{p} upper bound. Relatedly, we show that a variety of other natural problems regarding minimal or minimum-size covering sets are hard or complete for either of NP, coNP, and Theta_{2}^{p}. An important consequence of our results is that neither minimal upward nor minimal downward covering sets (even when guaranteed to exist) can be computed in polynomial time unless P=NP. This sharply contrasts with Brandt and Fischer's result that minimal bidirectional covering sets (i.e., sets that are both minimal upward and minimal downward covering sets) are polynomial-time computable.Comment: 27 pages, 7 figure

Caracterização de batata-doce de polpa roxa (ipomoea batatas (l.) lam.) em duas safras.

O objetivo desse trabalho foi a caracterização físico-química de um genótipo de batata-doce de polpa roxa (Ipomoea batatas (L.) Lam.) proveniente do banco de germoplasma da Embrapa Clima Temperado e produzido por um produtor local

Herança alimentar: investigação do uso e da variabilidade físico-química do butiá-da-serra (Butia eriospatha, Arecaceae).

Butia eriospatha é uma palmeira nativa vinculada a cultura do Sul do Brasil, que se encontra ameaçada de extinção. O objetivo deste trabalho foi investigar o conhecimento local e a variabilidade físico-química de B. eriospatha. Foi realizado levantamento etnobotânico através de entrevistas com questionários semi-estruturados nos municípios de Rio das Antas e Curitibanos (SC). Foram avaliados sólidos solúveis totais, pH, acidez titulável, vitamina C, cinzas e matéria seca de três genótipos de uma população natural de Ponte Alta do Norte, e três de Rio das Antas. Utilizou-se ANOVA, e teste de Tukey para comparação das médias dos genótipos. Todas as variáveis apresentaram diferença estatística, havendo também diferenças dentro das populações. Foram realizadas sete entrevistas, onde 13 usos foram mencionados, com sete menções de uso dos frutos, quatro das amêndoas, uma das folhas e uma das espatas. Foi constatada variabilidade entre os genótipos e versatilidade de usos para B. eriospatha

Downfolding from Ab Initio to Interacting Model Hamiltonians: Comprehensive Analysis and Benchmarking

Model Hamiltonians are regularly derived from first-principles data to describe correlated matter. However, the standard methods for this contain a number of largely unexplored approximations. For a strongly correlated impurity model system, here we carefully compare standard downfolding techniques with the best-possible ground-truth estimates for charge-neutral excited state energies and charge densities using state-of-the-art first-principles many-body wave function approaches. To this end, we use the vanadocene molecule and analyze all downfolding aspects, including the Hamiltonian form, target basis, double counting correction, and Coulomb interaction screening models. We find that the choice of target-space basis functions emerges as a key factor for the quality of the downfolded results, while orbital-dependent double counting correction diminishes the quality. Background screening to the Coulomb interaction matrix elements primarily affects crystal-field excitations. Our benchmark uncovers the relative importance of each downfolding step and offers insights into the potential accuracy of minimal downfolded model Hamiltonians.Comment: 15 pages (+8 pages Supplemental Material), 8 figure

Evaluation of bioactive compounds in two natural populations of Butia catarinensis Noblick & Lorenzi.

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