Exploiting Resolution-based Representations for MaxSAT Solving

Most recent MaxSAT algorithms rely on a succession of calls to a SAT solver in order to find an optimal solution. In particular, several algorithms take advantage of the ability of SAT solvers to identify unsatisfiable subformulas. Usually, these MaxSAT algorithms perform better when small unsatisfiable subformulas are found early. However, this is not the case in many problem instances, since the whole formula is given to the SAT solver in each call. In this paper, we propose to partition the MaxSAT formula using a resolution-based graph representation. Partitions are then iteratively joined by using a proximity measure extracted from the graph representation of the formula. The algorithm ends when only one partition remains and the optimal solution is found. Experimental results show that this new approach further enhances a state of the art MaxSAT solver to optimally solve a larger set of industrial problem instances

Neotropical Cerambycidae (Coleoptera) primarily in the Canadian Museum of Nature, Ottawa. I. Falsamblesthiini (Lamiinae)

The following new species are described: Nyctonympha andersoni, sp. n., and N. howdenarum, sp. n., both from Colombia; N. genieri, sp. n., from Ecuador; N. taeniata, sp. n., from Trinidad; Falsamblesthis microps, sp. n., from Venezuela; Bactriola circundata, sp. n., from Brazil (Rio de Janeiro); B. maculata, sp. n., from Venezuela and Ecuador; and B. falsa, sp. n., from Brazil (Minas Gerais to Rio Grande do Sul). A redescription of Bactriola vittulata Bates, 1886, herein designated as the type species of the genus, is provided. Accurate data on the occurrence of Saepiseuthes chilensis Thomson, 1868, in Chile are given. Keys to the species of Bactriola Bates, 1886 and Nyctonympha Thomson, 1868 are added

Large-Eddy Simulation closures of passive scalar turbulence: a systematic approach

The issue of the parameterization of small scale (``subgrid'') turbulence is addressed in the context of passive scalar transport. We focus on the Kraichnan advection model which lends itself to the analytical investigation of the closure problem. We derive systematically the dynamical equations which rule the evolution of the coarse-grained scalar field. At the lowest-order approximation in $l/r$, $l$ being the characteristic scale of the filter defining the coarse-grained scalar field and $r$ the inertial range separation, we recover the classical eddy-diffusivity parameterization of small scales. At the next-leading order a dynamical closure is obtained. The latter outperforms the classical model and is therefore a natural candidate for subgrid modelling of scalar transport in generic turbulent flows.Comment: 10 LaTex pages, 1 PS figure. Changes: comments added below previous (3.10); Previous (3.16) has been corrected; Minor changes in the conclusion

Large model footing tests on a sandy clay till

Imperial Users onl

Note on improvement precision of recursive function simulation in floating point standard

An improvement on precision of recursive function simulation in IEEE floating point standard is presented. It is shown that the average of rounding towards negative infinite and rounding towards positive infinite yields a better result than the usual standard rounding to the nearest in the simulation of recursive functions. In general, the method improves one digit of precision and it has also been useful to avoid divergence from a correct stationary regime in the logistic map. Numerical studies are presented to illustrate the method.Comment: DINCON 2017 - Conferencia Brasileira de Dinamica, Controle e Aplicacoes - Sao Jose do Rio Preto - Brazil. 8 page

Multicolored Temperley-Lieb lattice models. The ground state

Using inversion relation, we calculate the ground state energy for the lattice integrable models, based on a recently obtained baxterization of non trivial multicolored generalization of Temperley-Lieb algebras. The simplest vertex and IRF models are analyzed and found to have a mass gap.Comment: 15 pages 2 figure

Emergence of Hierarchy on a Network of Complementary Agents

Complementarity is one of the main features underlying the interactions in biological and biochemical systems. Inspired by those systems we propose a model for the dynamical evolution of a system composed by agents that interact due to their complementary attributes rather than their similarities. Each agent is represented by a bit-string and has an activity associated to it; the coupling among complementary peers depends on their activity. The connectivity of the system changes in time respecting the constraint of complementarity. We observe the formation of a network of active agents whose stability depends on the rate at which activity diffuses in the system. The model exhibits a non-equilibrium phase transition between the ordered phase, where a stable network is generated, and a disordered phase characterized by the absence of correlation among the agents. The ordered phase exhibits multi-modal distributions of connectivity and activity, indicating a hierarchy of interaction among different populations characterized by different degrees of activity. This model may be used to study the hierarchy observed in social organizations as well as in business and other networks.Comment: 13 pages, 4 figures, submitte