Explicit Evidence Systems with Common Knowledge

Justification logics are epistemic logics that explicitly include justifications for the agents' knowledge. We develop a multi-agent justification logic with evidence terms for individual agents as well as for common knowledge. We define a Kripke-style semantics that is similar to Fitting's semantics for the Logic of Proofs LP. We show the soundness, completeness, and finite model property of our multi-agent justification logic with respect to this Kripke-style semantics. We demonstrate that our logic is a conservative extension of Yavorskaya's minimal bimodal explicit evidence logic, which is a two-agent version of LP. We discuss the relationship of our logic to the multi-agent modal logic S4 with common knowledge. Finally, we give a brief analysis of the coordinated attack problem in the newly developed language of our logic

Cómo adaptar un modelo de aprendizaje profundo a un nuevo dominio: el caso de la extracción de relaciones biomédicas

In this article, we study the relation extraction problem from Natural Language Processing (NLP) implementing a domain adaptation setting without external resources. We trained a Deep Learning (DL) model for Relation Extraction (RE), which extracts semantic relations in the biomedical domain. However, can the model be applied to different domains? The model should be adaptable to automatically extract relationships across different domains using the DL network. Completely training DL models in a short time is impractical because the models should quickly adapt to different datasets in several domains without delay. Therefore, adaptation is crucial for intelligent systems, where changing factors and unanticipated perturbations are common. In this study, we present a detailed analysis of the problem, as well as preliminary experimentation, results, and their evaluation.En este trabajo estudiamos el problema de extracción de relaciones del Procesamiento de Lenguaje Natural (PLN). Realizamos una configuración para la adaptación de dominio sin recursos externos. De esta forma, entrenamos un modelo con aprendizaje profundo (DL) para la extracción de relaciones (RE). El modelo permite extraer relaciones semánticas para el dominio biomédico. Sin embargo, ¿El modelo puede ser aplicado a diferentes dominios? El modelo debería adaptarse automáticamente para la extracción de relaciones entre diferentes dominios usando la red de DL. Entrenar completamente modelos DL en una escala de tiempo corta no es práctico, deseamos que los modelos se adapten rápidamente de diferentes conjuntos de datos con varios dominios y sin demora. Así, la adaptación es crucial para los sistemas inteligentes que operan en el mundo real, donde los factores cambiantes y las perturbaciones imprevistas son habituales. En este artículo, presentamos un análisis detallado del problema, una experimentación preliminar, resultados y la discusión acerca de los resultados

How to Determine the Environmental Exposure of PAHs Originating from Biochar

Biochars are obtained by pyrolyzing biomass materials and are increasingly used within the agricultural sector. Owing to the production process, biochars can contain polycyclic aromatic hydrocarbons (PAHs) in the high mg/kg range, which makes the determination of the environmental exposure of PAHs originating from biochars relevant. However, PAH sorption to biochar is characterized by very high (10⁴–10⁶ L/kg) or extreme distribution coefficients (<i>K</i>_D) (>10⁶ L/kg), which makes the determination of exposure scientifically and technically challenging. Cyclodextrin extractions, sorptive bioaccessibility extractions, Tenax extractions, contaminant traps, and equilibrium sampling were assessed and selected methods used for the determination of bioavailability parameters for PAHs in two model biochars. Results showed that: (1) the <i>K</i>_D values of typically 10⁶–10⁹ L/kg made the biochars often act as sinks, rather than sources, of PAHs. (2) Equilibrium sampling yielded freely dissolved concentrations (pg–ng/L range) that were below or near environmental background levels. (3) None of the methods were found to be suitable for the direct measurement of the readily desorbing fractions of PAHs (i.e., bioacessibility) in the two biochars. (4) The contaminant-trap method yielded desorption-resistant PAH fractions of typically 90–100%, implying bioaccessibility in the high μg/kg to low mg/kg range

Environmental Exposure to Estrogenic and other Myco- and Phytotoxins

Zearalenone (ZON) is known as a very potent, naturally occurring estrogenic mycotoxin. It is one of the most prevalent mycotoxin produced as a secondary metabolite by Fusarium species growing on cereals such as wheat and corn. It has been studied extensively in food and feed products for decades but only rarely and somewhat by chance in the environment. We therefore elucidated its agro-environmental fate and behavior by conducting a series of field studies and monitoring campaigns. Specifically, ZON was investigated in plants, soils and drainage waters from wheat and corn fields artificially infected with Fusarium graminearum. In addition, manure, sewage sludge and surface waters were analyzed for ZON. Three main input pathways of ZON onto soil could be identified: i) wash-off from Fusarium-infected plants (in the order of 100 mg/ha), ii) plant debris remaining on the soil after harvest (up to few g/ha), and iii) manure application (in the order of 100 mg/ha). Our results show that these input sources altogether caused the presence of several g/ha of ZON in topsoil. Compared to this, ZON emission by drainage water from Fusarium-infected fields was generally low, with maximum concentrations of 35 ng/l and total amounts of a few mg/ha. Due to dilution, ZON concentrations dropped below environmental relevance in larger surface water bodies. However in small catchments dominated by runoff from agricultural land, ZON might substantially contribute to the estrogenicity of such waters. Apart from ZON, other natural toxins monitored in this study, such as the mycotoxin deoxynivalenol or the estrogenic phytoestrogen formononetin, emitted to and occurred in surface waters at considerably higher amounts. To date their ecotoxicological effects are largely unknown

Marginal Pinning of Quenched Random Polymers

An elastic string embedded in 3D space and subject to a short-range correlated random potential exhibits marginal pinning at high temperatures, with the pinning length $L_c(T)$ becoming exponentially sensitive to temperature. Using a functional renormalization group (FRG) approach we find $L_c(T) \propto \exp[(32/\pi)(T/T_{\rm dp})^3]$, with $T_{\rm dp}$ the depinning temperature. A slow decay of disorder correlations as it appears in the problem of flux line pinning in superconductors modifies this result, $\ln L_c(T)\propto T^{3/2}$.Comment: 4 pages, RevTeX, 1 figure inserte

Functional Renormalization Group and the Field Theory of Disordered Elastic Systems

We study elastic systems such as interfaces or lattices, pinned by quenched disorder. To escape triviality as a result of ``dimensional reduction'', we use the functional renormalization group. Difficulties arise in the calculation of the renormalization group functions beyond 1-loop order. Even worse, observables such as the 2-point correlation function exhibit the same problem already at 1-loop order. These difficulties are due to the non-analyticity of the renormalized disorder correlator at zero temperature, which is inherent to the physics beyond the Larkin length, characterized by many metastable states. As a result, 2-loop diagrams, which involve derivatives of the disorder correlator at the non-analytic point, are naively "ambiguous''. We examine several routes out of this dilemma, which lead to a unique renormalizable field-theory at 2-loop order. It is also the only theory consistent with the potentiality of the problem. The beta-function differs from previous work and the one at depinning by novel "anomalous terms''. For interfaces and random bond disorder we find a roughness exponent zeta = 0.20829804 epsilon + 0.006858 epsilon^2, epsilon = 4-d. For random field disorder we find zeta = epsilon/3 and compute universal amplitudes to order epsilon^2. For periodic systems we evaluate the universal amplitude of the 2-point function. We also clarify the dependence of universal amplitudes on the boundary conditions at large scale. All predictions are in good agreement with numerical and exact results, and an improvement over one loop. Finally we calculate higher correlation functions, which turn out to be equivalent to those at depinning to leading order in epsilon.Comment: 42 pages, 41 figure

How Information Technology Assimilation Promotes Exploratory and Exploitative Innovation in the Small- and Medium-Sized Firm Context: The Role of Contextual Ambidexterity and Knowledge Base

This research sheds new light on how information technology (IT) assimilation affects exploratory and exploitative innovation in the context of small- and medium-sized firms (SMEs). This contextualization is important in establishing the boundary conditions for the theory, as well as generating specific managerial insights for SME managers. A sample of 248 UK-based SMEs in the manufacturing industry demonstrates contextual ambidexterity (CA) mediates the relationship between IT assimilation and two types of innovation. This finding highlights that IT assimilation does not automatically promote innovation. Instead, IT assimilation represents a critical resource that enables the effective implementation of CA, which in turn affects innovation. This implies that SMEs cannot fully realize the potential of their IT assimilation and use it to enable innovation without implementing CA. Furthermore, this study differentiates between two different dimensions of knowledge base: knowledge breadth and knowledge depth. This study finds that knowledge breadth moderates the indirect IT assimilation-exploratory innovation relationship by influencing the effect of CA on exploratory innovation. Knowledge depth, on the other hand, moderates the indirect IT assimilation-exploitative innovation relationship by influencing the effect of CA on exploitative innovation. This finding implies that SMEs can benefit from their IT assimilation that enables them to engage in CA, which in turn allows them to perform innovation. However, it is apparent that the dimension of knowledge that SMEs hold internally can determine what types of innovation that they are able to perform

2-loop Functional Renormalization Group Theory of the Depinning Transition

We construct the field theory which describes the universal properties of the quasi-static isotropic depinning transition for interfaces and elastic periodic systems at zero temperature, taking properly into account the non-analytic form of the dynamical action. This cures the inability of the 1-loop flow-equations to distinguish between statics and quasi-static depinning, and thus to account for the irreversibility of the latter. We prove two-loop renormalizability, obtain the 2-loop beta-function and show the generation of "irreversible" anomalous terms, originating from the non-analytic nature of the theory, which cause the statics and driven dynamics to differ at 2-loop order. We obtain the roughness exponent zeta and dynamical exponent z to order epsilon^2. This allows to test several previous conjectures made on the basis of the 1-loop result. First it demonstrates that random-field disorder does indeed attract all disorder of shorter range. It also shows that the conjecture zeta=epsilon/3 is incorrect, and allows to compute the violations, as zeta=epsilon/3 (1 + 0.14331 epsilon), epsilon=4-d. This solves a longstanding discrepancy with simulations. For long-range elasticity it yields zeta=epsilon/3 (1 + 0.39735 epsilon), epsilon=2-d (vs. the standard prediction zeta=1/3 for d=1), in reasonable agreement with the most recent simulations. The high value of zeta approximately 0.5 found in experiments both on the contact line depinning of liquid Helium and on slow crack fronts is discussed.Comment: 32 pages, 17 figures, revtex