Dynamic Provenance for SPARQL Update

While the Semantic Web currently can exhibit provenance information by using the W3C PROV standards, there is a "missing link" in connecting PROV to storing and querying for dynamic changes to RDF graphs using SPARQL. Solving this problem would be required for such clear use-cases as the creation of version control systems for RDF. While some provenance models and annotation techniques for storing and querying provenance data originally developed with databases or workflows in mind transfer readily to RDF and SPARQL, these techniques do not readily adapt to describing changes in dynamic RDF datasets over time. In this paper we explore how to adapt the dynamic copy-paste provenance model of Buneman et al. [2] to RDF datasets that change over time in response to SPARQL updates, how to represent the resulting provenance records themselves as RDF in a manner compatible with W3C PROV, and how the provenance information can be defined by reinterpreting SPARQL updates. The primary contribution of this paper is a semantic framework that enables the semantics of SPARQL Update to be used as the basis for a 'cut-and-paste' provenance model in a principled manner.Comment: Pre-publication version of ISWC 2014 pape

Yang-Lee Theory for a Nonequilibrium Phase Transition

To analyze phase transitions in a nonequilibrium system we study its grand canonical partition function as a function of complex fugacity. Real and positive roots of the partition function mark phase transitions. This behavior, first found by Yang and Lee under general conditions for equilibrium systems, can also be applied to nonequilibrium phase transitions. We consider a one-dimensional diffusion model with periodic boundary conditions. Depending on the diffusion rates, we find real and positive roots and can distinguish two regions of analyticity, which can identified with two different phases. In a region of the parameter space both of these phases coexist. The condensation point can be computed with high accuracy.Comment: 4 pages, accepted for publication in Phys.Rev.Let

Dynamics of driven interfaces near isotropic percolation transition

We consider the dynamics and kinetic roughening of interfaces embedded in uniformly random media near percolation treshold. In particular, we study simple discrete ``forest fire'' lattice models through Monte Carlo simulations in two and three spatial dimensions. An interface generated in the models is found to display complex behavior. Away from the percolation transition, the interface is self-affine with asymptotic dynamics consistent with the Kardar-Parisi-Zhang universality class. However, in the vicinity of the percolation transition, there is a different behavior at earlier times. By scaling arguments we show that the global scaling exponents associated with the kinetic roughening of the interface can be obtained from the properties of the underlying percolation cluster. Our numerical results are in good agreement with theory. However, we demonstrate that at the depinning transition, the interface as defined in the models is no longer self-affine. Finally, we compare these results to those obtained from a more realistic reaction-diffusion model of slow combustion.Comment: 7 pages, 9 figures, to appear in Phys. Rev. E (1998

Anomalous Roughness in Dimer-Type Surface Growth

We point out how geometric features affect the scaling properties of non-equilibrium dynamic processes, by a model for surface growth where particles can deposit and evaporate only in dimer form, but dissociate on the surface. Pinning valleys (hill tops) develop spontaneously and the surface facets for all growth (evaporation) biases. More intriguingly, the scaling properties of the rough one dimensional equilibrium surface are anomalous. Its width, $W\sim L^\alpha$, diverges with system size $L$, as $\alpha={1/3}$ instead of the conventional universal value $\alpha={1/2}$. This originates from a topological non-local evenness constraint on the surface configurations.Comment: Published version in PR

Force distribution in a scalar model for non-cohesive granular material

We study a scalar lattice model for inter-grain forces in static, non-cohesive, granular materials, obtaining two primary results. (i) The applied stress as a function of overall strain shows a power law dependence with a nontrivial exponent, which moreover varies with system geometry. (ii) Probability distributions for forces on individual grains appear Gaussian at all stages of compression, showing no evidence of exponential tails. With regard to both results, we identify correlations responsible for deviations from previously suggested theories.Comment: 16 pages, 9 figures, Submitted to PR

Geospatial Approaches to Support Pelagic Conservation Planning and Adaptive Management

Place-based management in the open ocean faces unique challenges in delineating boundaries around temporally and spatially dynamic systems that span broad geographic scales and multiple management jurisdictions, especially in the \u27high seas\u27. Geospatial technologies are critical for the successful design of pelagic conservation areas, because they provide information on the spatially and temporally dynamic oceanographic features responsible for driving species distribution and abundance in the open ocean, the movements of protected species, and the spatial patterns of distribution of potential threats. Nevertheless, there are major challenges to implementing these geospatial approaches in the open ocean. This Theme Section seeks to bridge the gap between geospatial science and marine conservation by discussing the use of innovative approaches to support effective marine conservation planning strategies for pelagic ecosystems. We highlight the results of this collection of contributions in 3 main sections: (1) conceptual advances in pelagic conservation; (2) novel information technologies and methodologies; and (3) case studies in the California Current and Pacific Ocean

Height Fluctuations and Intermittency of V2O5V_2 O_5 Films by Atomic Force Microscopy

The spatial scaling law and intermittency of the $V_2 O_5$ surface roughness by atomic force microscopy has been investigated. The intermittency of the height fluctuations has been checked by two different methods, first, by measuring scaling exponent of q-th moment of height-difference fluctuations i.e. $C_q =$ and the second, by defining generating function $Z(q,N)$ and generalized multi-fractal dimension $D_q$. These methods predict that there is no intermittency in the height fluctuations. The observed roughness and dynamical exponents can be explained by the numerical simulation on the basis of forced Kuramoto-Sivashinsky equation.Comment: 6 pages (two columns), 11 eps. figures, late

Pinning-induced transition to disordered vortex phase in layered superconductors

Destruction of the vortex lattice by random point pinning is considered as a mechanism of the ``second peak'' transition observed experimentally in weakly coupled layered high temperature superconductors. The transition field separating the topologically ordered quasilattice from the amorphous vortex configuration is strongly influenced by the layered structure and by the nonlocal nature of the vortex tilt energy due to the magnetic interlayer coupling. We found three different regimes of transition depending on the relative strength of the Josephson and magnetic couplings. The regimes can be distinguished by the dependence of the transition fieldComment: 8 pages, 3 Postscript figures. Accepted to Phys. Rev.B. (regular article

Conservation Laws and Integrability of a One-dimensional Model of Diffusing Dimers

We study a model of assisted diffusion of hard-core particles on a line. The model shows strongly ergodicity breaking : configuration space breaks up into an exponentially large number of disconnected sectors. We determine this sector-decomposion exactly. Within each sector the model is reducible to the simple exclusion process, and is thus equivalent to the Heisenberg model and is fully integrable. We discuss additional symmetries of the equivalent quantum Hamiltonian which relate observables in different sectors. In some sectors, the long-time decay of correlation functions is qualitatively different from that of the simple exclusion process. These decays in different sectors are deduced from an exact mapping to a model of the diffusion of hard-core random walkers with conserved spins, and are also verified numerically. We also discuss some implications of the existence of an infinity of conservation laws for a hydrodynamic description.Comment: 39 pages, with 5 eps figures, to appear in J. Stat. Phys. (March 1997

Delocalization Transition of a Rough Adsorption-Reaction Interface

We introduce a new kinetic interface model suitable for simulating adsorption-reaction processes which take place preferentially at surface defects such as steps and vacancies. As the average interface velocity is taken to zero, the self- affine interface with Kardar-Parisi-Zhang like scaling behaviour undergoes a delocalization transition with critical exponents that fall into a novel universality class. As the critical point is approached, the interface becomes a multi-valued, multiply connected self-similar fractal set. The scaling behaviour and critical exponents of the relevant correlation functions are determined from Monte Carlo simulations and scaling arguments.Comment: 4 pages with 6 figures, new comment