Faster Query Answering in Probabilistic Databases using Read-Once Functions

A boolean expression is in read-once form if each of its variables appears exactly once. When the variables denote independent events in a probability space, the probability of the event denoted by the whole expression in read-once form can be computed in polynomial time (whereas the general problem for arbitrary expressions is #P-complete). Known approaches to checking read-once property seem to require putting these expressions in disjunctive normal form. In this paper, we tell a better story for a large subclass of boolean event expressions: those that are generated by conjunctive queries without self-joins and on tuple-independent probabilistic databases. We first show that given a tuple-independent representation and the provenance graph of an SPJ query plan without self-joins, we can, without using the DNF of a result event expression, efficiently compute its co-occurrence graph. From this, the read-once form can already, if it exists, be computed efficiently using existing techniques. Our second and key contribution is a complete, efficient, and simple to implement algorithm for computing the read-once forms (whenever they exist) directly, using a new concept, that of co-table graph, which can be significantly smaller than the co-occurrence graph.Comment: Accepted in ICDT 201

Faster query answering in probalistic databases using read-once functions

A boolean expression is in read-once form if each of its variables appears exactly once. When the variables denote independent events in a probability space, the probability of the event denoted by the whole expression in read-once form can be computed in polynomial time (whereas the general problem for arbitrary expressions is #P-complete). Known approaches to checking read-once property seem to require putting these expressions in disjunctive normal form. In this paper, we tell a better story for a large subclass of boolean event expressions: those that are generated by conjunctive queries without self-joins and on tuple-independent probabilistic databases. We first show that given a tuple-independent representation and the provenance graph of an SPJ query plan without self-joins, we can, without using the DNF of a result event expression, efficiently compute its co-occurrence graph. From this, the read-once form can already, if it exists, be computed efficiently using existing techniques. Our second and key contribution is a complete, efficient, and simple to implement algorithm for computing the read-once forms (whenever they exist) directly, using a new concept, that of co-table graph, which can be significantly smaller than the cooccurrence graph

High-efficiency orange and yellow organic light-emitting devices using platinum(II) complexes containing extended π -conjugated cyclometalated ligands as dopant materials

Two luminescent platinum(II) complexes 1 and 2 containing extended π -conjugated cyclometalated ligands have been used as dopant materials for the construction of two high-efficiency organic light-emitting devices I and II. Device I (containing dopant 1) emits orange emission and exhibits a maximum external quantum efficiency of 12.4%, a maximum luminous efficiency of 32.3 cdA, and a maximum power efficiency of 11.2 lmW. Device II (containing dopant 2) emits yellow light and exhibits a maximum external quantum efficiency of 16.1%, a maximum luminous efficiency of 51.8 cdA, and a maximum power efficiency of 23.2 lmW. © 2007 American Institute of Physics.published_or_final_versio

Luminescent and structural properties of ZnO nanorods prepared under different conditions

Author name used in this publication: C. Surya2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Reconfigurable Surfaces Using Fringing Electric Fields from Nanostructured Electrodes in Nematic Liquid Crystals

Liquid crystals with a varying phase profile enable reconfigurable and intelligent devices to be designed, which are capable of manipulating incident electromagnetic fields in display, telecommunications as well as wearable applications. The active control of defects in these devices is becoming more important, especially since the electrodes used to manipulate them are shrinking to nanometer length scales. In this paper, a simple subwavelength, 1D, interdigitated metal electrode structure that can be reconfigured using nematic liquid crystals aligned in the homeotropic, planar, and hybrid methods are demonstrated. Accurate electro-optic modeling of the directors and the defects are shown, which are induced by the fringing electric fields. Applied voltages result in liquid crystal reorientation near the bottom surface, such that defects are induced between the electrodes. The height of the electrodes does not affect the lateral position of these defects. Rather, this can be achieved by increasing the biasing voltage on the top electrode, which also leads to greater splay-bend in the bulk of the material. These results therefore aim to generalize the control of defects in complex anisotropic nematic liquid crystals using simple interdigitated structures for a range of reconfigurable intelligent surface applications

Las matemáticas a través de la robótica y programación en educación infantil

Una de las tendencias de la innovación educativa hoy en día, es la inclusión de la robótica y los inicios de la programación en las aulas, incluso desde Educación Infantil. Después de indagar en las posibilidades y los beneficios para el aprendizaje de nuestros alumnos y alumnas, se ha planteado una propuesta didáctica de iniciación a estas nuevas disciplinas, en la que se van a destacar los contenidos matemáticos que aparecen en la misma. En esta adaptación de la escuela a la realidad social, además de formación al profesorado y aparatos electrónicos, hay que plantearse cómo aprovechar el contexto, aunque sea adverso. Esta propuesta puede implementarse en cualquier aula de infantil. <br /

Nanocomposite field effect transistors based on zinc oxide/polymer blends

The authors have examined the field effect behavior of nanocomposite field effect transistors containing ZnO (zinc oxide) tetrapods or nanocrystals dispersed in a polymer matrix of poly[2-methoxy,5-(2-ethylhexyloxy)-1,4- phenylenevinylene] (MEH-PPV). The electrical characteristics of ZnO tetrapods/MEH-PPV composite devices exhibit an increase in hole mobility up to three orders of magnitude higher than the polymer MEH-PPV device. © 2007 American Institute of Physics.published_or_final_versio

Magnetic properties of Mn doped ZnO tetrapod structures

Author name used in this publication: C. Surya2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

High genomic diversity and heterogenous origins of pathogenic and antibiotic-resistant Escherichia coli in household settings represent a challenge to reducing transmission in low-income settings

Escherichia coli; is present in multiple hosts and environmental compartments as a normal inhabitant, temporary or persistent colonizer, and as a pathogen. Transmission of; E. coli; between hosts and with the environment is considered to occur more often in areas with poor sanitation. We performed whole-genome comparative analyses on 60; E. coli; isolates from soils and fecal sources (cattle, chickens, and humans) in households in rural Bangladesh. Isolates from household soils were in multiple branches of the reconstructed phylogeny, intermixed with isolates from fecal sources. Pairwise differences between all strain pairs were large (minimum, 189 single nucleotide polymorphisms [SNPs]), suggesting high diversity and heterogeneous origins of the isolates. The presence of multiple virulence and antibiotic resistance genes is indicative of the risk that; E. coli; from soil and feces represent for the transmission of variants that pose potential harm to people. Analysis of the accessory genomes of the Bangladeshi; E. coli; relative to; E. coli; genomes available in NCBI identified a common pool of accessory genes shared among; E. coli; isolates in this geographic area. Together, these findings indicate that in rural Bangladesh, a high level of; E. coli; in soil is likely driven by contributions from multiple and diverse; E. coli; sources (human and animal) that share an accessory gene pool relatively unique to previously published; E. coli; genomes. Thus, interventions to reduce environmental pathogen or antimicrobial resistance transmission should adopt integrated One Health approaches that consider heterogeneous origins and high diversity to improve effectiveness and reduce prevalence and transmission.; IMPORTANCE; Escherichia coli; is reported in high levels in household soil in low-income settings. When; E. coli; reaches a soil environment, different mechanisms, including survival, clonal expansion, and genetic exchange, have the potential to either maintain or generate; E. coli; variants with capabilities of causing harm to people. In this study, we used whole-genome sequencing to identify that; E. coli; isolates collected from rural Bangladeshi household soils, including pathogenic and antibiotic-resistant variants, are diverse and likely originated from multiple diverse sources. In addition, we observed specialization of the accessory genome of this Bangladeshi; E. coli; compared to; E. coli; genomes available in current sequence databases. Thus, to address the high level of pathogenic and antibiotic-resistant; E. coli; transmission in low-income settings, interventions should focus on addressing the heterogeneous origins and high diversity